Master Investment Portfolio N-CSR Certified annual shareholder report (management investment company)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMN-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT

COMPANIES

Investment Company Act file number:811-07332 and811-08162

Name of Fund:   BlackRock Funds III

BlackRock Cash Funds: Institutional

BlackRock Cash Funds: Treasury

BlackRock LifePath® Dynamic Retirement Fund

BlackRock LifePath® Dynamic 2025 Fund

BlackRock LifePath® Dynamic 2030 Fund

BlackRock LifePath® Dynamic 2035 Fund

BlackRock LifePath® Dynamic 2040 Fund

BlackRock LifePath® Dynamic 2045 Fund

BlackRock LifePath® Dynamic 2050 Fund

BlackRock LifePath® Dynamic 2055 Fund

BlackRock LifePath® Dynamic 2060 Fund

BlackRock LifePath® Dynamic 2065 Fund

iShares MSCI Total International Index Fund

iShares Russell 1000Large-Cap Index Fund

iShares S&P 500 Index Fund

iShares U.S. Aggregate Bond Index Fund

Master Investment Portfolio

Active Stock Master Portfolio

International Tilts Master Portfolio

Large Cap Index Master Portfolio

LifePath® Dynamic Retirement Master Portfolio

LifePath® Dynamic 2025 Master Portfolio

LifePath® Dynamic 2030 Master Portfolio

LifePath® Dynamic 2035 Master Portfolio

LifePath® Dynamic 2040 Master Portfolio

LifePath® Dynamic 2045 Master Portfolio

LifePath® Dynamic 2050 Master Portfolio

LifePath® Dynamic 2055 Master Portfolio

LifePath® Dynamic 2060 Master Portfolio

LifePath® Dynamic 2065 Master Portfolio

Money Market Master Portfolio

S&P 500 Index Master Portfolio

Total International ex U.S. Index Master Portfolio

Treasury Money Market Master Portfolio

U.S. Total Bond Index Master Portfolio

Fund Address:    100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: John M. Perlowski, Chief Executive Officer, BlackRock Funds III and Master Investment Portfolio, 55 East 52^nd Street, New York, NY 10055

Registrants’ telephone number, including area code: (800)537-4942

Date of fiscal year end: 12/31/2019

Date of reporting period: 12/31/2019

Item 1 – Report to Stockholders

2

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· BlackRock Cash Funds: Institutional

· BlackRock Cash Funds: Treasury

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of each Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call(888) 204-3956 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Money Market Overview		4
Fund Information		5
Disclosure of Expenses		5
Fund Financial Statements:
Statements of Assets and Liabilities		6
Statements of Operations		7
Statements of Changes in Net Assets		8
Fund Financial Highlights		9
Fund Notes to Financial Statements		12
Fund Report of Independent Registered Public Accounting Firm		16
Important Tax Information		16
Master Portfolio Information		17
Master Portfolio Financial Statements:
Schedules of Investments		18
Statements of Assets and Liabilities		28
Statements of Operations		29
Statements of Changes in Net Assets		30
Master Portfolio Financial Highlights		31
Master Portfolio Notes to Financial Statements		33
Master Portfolio Report of Independent Registered Public Accounting Firm		37
Trustee and Officer Information		38
Additional Information		42
Glossary of Terms Used in this Report		43
Important Fund Information		43

3

Money Market Overview  For the 12-Month Period Ended December 31, 2019

2019 is officially in the books — as the year progressed, investors witnessed a pivot from the Fed hiking rates in 2018 to delivering 0.25% cuts in July, September and October to the Federal Funds target rate, which ended the year in a range of 1.50%-1.75%. Prompting these cuts, in our view, were concerns about slowing global growth amid uncertainties associated with geopolitical events, including U.S.-China trade tensions, and muted inflation. We believe such concerns were also reflected in the slope of the U.S. Treasury yield curve between three months and 10 years, which was periodically inverted during 2019. However, even as the U.S. economy began to exhibit signs of softness, a strong labor market and rising consumer spending helped keep the economic expansion intact, with the support of the Fed’s more accommodative policy. The future path for the Federal Funds rate looks to be stable for the foreseeable future as the Fed has acknowledged, in our opinion, a relatively high bar for further policy action.

Another notable event this year was the bout of temporary excessive volatility in the repurchase agreement (“repo”) market inmid-September, which was due in part to a prior contraction in excess reserves in the banking system and outsized deposit flow activity related to corporate tax payments and the settlement of Treasury obligations. This situation prompted the Fed to inject a substantial amount of liquidity into the financial system during the balance of the year. Specifically, the Fed conducted regular overnight and term repo operations (known as temporary open market operations), and also began purchasing Treasury bills beginning at a rate of $60 billion per month in order to support the flow of funds and help maintain control over short-term interest rates. The dislocations in the repo market highlighted, in our opinion, the need for the Fed to determine the appropriate level of excess reserves in the post financial crisis regulatory environment.

In July, the U.S. debt ceiling was again suspended, and net new Treasury bill issuance exceeded $250 billion in 2019. That said, the expanded footprint by the Fed in the Treasury bill market, in our view, contributed to a reduction in investable supply available to the public and, in part, caused a contraction in the relative value of such instruments during the latter part of the year.

Another important development in 2019 included the government-sponsored agencies, having been guided by regulatory agencies, issuing floating rate notes indexed to the Secured Overnight Financing Rate (“SOFR”), a broad measure of the cost of borrowing cash overnight collateralized by Treasury securities, and the reference rate generally expected to replace the London Interbank Offered Rate (“LIBOR”). In addition to the agency notes referenced to SOFR, some large financial institutions also issued certificates of deposit and commercial paper linked to this index, and demand for such obligations was generally strong. Sticking on the topic of demand, asset flows into money market mutual funds and short duration bond funds were strong while primary market investment grade issuance was reportedly down rather markedly. This technical backdrop supported spreads in credit instruments during the year, and we believe this dynamic should continue to play out in 2020. Similar to 2018, we witnessed seasonal spread widening of the three-month LIBOR overnight-indexed swap spread, a general proxy for bank funding stress. In our opinion, issuers appeared willing to pay up in terms of additional yield spread to secure their funding needs over stress periods such as corporate tax payment days and balance sheet reporting dates, including most importantly year end, as investors paid close attention to the funding markets for clues to monetary system pressures.

With the market pricing in little action for further interest rate cuts, the Fed providing liquidity to the market during stress periods, assets continuing to flow into money market funds, and tentative optimism over the near-term outlook for global trade, we consider 2019 historic in many ways.

Looking ahead, as of the end of December, futures contracts were priced for less than one rate cut during 2020, with recent Fed comments reinforcing that policy is in a good place. We believe this market pricing to be slightly overdone, and we do not expect a further cut to the federal funds rate at this time — barring any adverse economic events.

In our opinion, we expect publicly available investable Treasury bill supply will remain negative into the first few months of 2020 as the Fed is expected to remain an active buyer of Treasury bills and potentially Treasury coupons in 2020. We also expect that investment grade corporate bond issuance will be flat to down for the year ahead as issuers may have already taken advantage of aflat-to-inverted yield curve in 2019. Finally, we look for the three-month LIBOR overnight-indexed swap spread to return to the historical average range of around 0.19%-0.25% as credit instruments, in our view, appear more attractive relative to short-dated Treasuries. Furthermore, we expect LIBOR to reset lower over the turn of the new year.

Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Information  as of December 31, 2019

BlackRock Cash Funds: Institutional

BlackRock Cash Funds: Institutional’s (the “Fund”) investment objective is to seek a high level of income consistent with liquidity and the preservation of capital.

	7-Day SEC Yield			7-Day Yield
SL Agency		1.87	%		1.87	%

BlackRock Cash Funds: Treasury

BlackRock Cash Funds: Treasury’s (the “Fund”) investment objective is to seek current income consistent with liquidity and stability of principal.

	7-Day SEC Yield			7-Day Yield
Institutional		1.52	%		1.52	%
SL Agency		1.55			1.55

The7-Day SEC Yields may differ from the7-Day Yields shown due to the fact that the7-Day SEC Yields exclude distributed capital gains.

Past performance is not indicative of future results.

Disclosure of Expenses

Shareholders of the Funds may incur the following charges: (a) transactional expenses; and (b) operating expenses, including administration fees, service and distribution fees, and other fund expenses. The expense examples shown below (which are based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019) are intended to assist shareholders both in calculating expenses based on an investment in each Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense examples provide information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their Fund and share class under the heading entitled “Expenses Paid During the Period.”

The expense examples also provide information about hypothetical account values and hypothetical expenses based on a Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in these Funds and other funds, compare the 5% hypothetical examples with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense examples are intended to highlight shareholders’ ongoing costs only and do not reflect any transactional expenses, such as sales charges, if any. Therefore, the hypothetical examples are useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

Expense Examples

	Actual						Hypothetical (b)
BlackRock Cash Funds: Institutional	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
SL Agency	$	1,000.00	$	1,010.80	$	0.46	$	1,000.00	$	1,024.75	$	0.46		0.09	%
BlackRock Cash Funds: Treasury
Institutional	$	1,000.00	$	1,009.50	$	0.61	$	1,000.00	$	1,024.60	$	0.61		0.12	%
SL Agency		1,000.00		1,009.70		0.46		1,000.00		1,024.75		0.46		0.09

^(a)  For each class of a Fund, expenses are equal to the annualized net expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect theone-half year period shown). Because each Fund invests all of its assets in its corresponding Master Portfolio, the expense examples reflect the net expenses of both the Fund and the Master Portfolio in which it invests.

^(b)  Hypothetical 5% annual return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

FUND INFORMATION / DISCLOSUREOF EXPENSES 5

Statements of Assets and Liabilities

December 31, 2019

	BlackRock Cash Funds: Institutional		BlackRock Cash Funds: Treasury
ASSETS
Investments at value — from the applicable Master Portfolio(a)	$	54,443,685,717	$	12,444,049,436
LIABILITIES
Payables:
Administration fees		1,049,241		398,902
Income dividend distributions		84,806,557		10,239,751
Other accrued expenses		10,992		10,998
Total liabilities		85,866,790		10,649,651
NET ASSETS	$	54,357,818,927	$	12,433,399,785
NET ASSETS CONSIST OF
Paid-in capital	$	54,340,060,752	$	12,431,933,855
Accumulated earnings		17,758,175		1,465,930
NET ASSETS	$	54,357,818,927	$	12,433,399,785
Institutional:
Net assets	$	—	$	1,813,190,758
Shares outstanding(b)		—		1,812,977,156
Net asset value	$	—	$	1.00
SL Agency:
Net assets	$	54,357,818,927	$	10,620,209,027
Shares outstanding(b)		54,334,687,432		10,618,956,701
Net asset value	$	1.0004	$	1.00

^(a)  Money Market Master Portfolio and Treasury Money Market Master Portfolio (each, a “Master Portfolio”), respectively.

^(b)  Unlimited number of shares authorized, no par value.

See notes to financial statements.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Operations

Year Ended December 31, 2019

	BlackRock Cash Funds: Institutional			BlackRock Cash Funds: Treasury
INVESTMENT INCOME
Net investment income allocated from the applicable Master Portfolio:
Interest — unaffiliated	$	1,254,372,445		$	200,666,792
Expenses		(51,790,348	)		(9,354,314	)
Fees waived		15,929,900			2,920,982
Total investment income		1,218,511,997			194,233,460
FUND EXPENSES
Administration — class specific		10,210,480			2,278,056
Professional		10,975			11,003
Miscellaneous		11,249			3,500
Total expenses		10,232,704			2,292,559
Less fees waived and/or reimbursed by the Administrator		(10,975	)		(11,003	)
Total expenses after fees waived and/or reimbursed		10,221,729			2,281,556
Net investment income		1,208,290,268			191,951,904
REALIZED AND UNREALIZED GAIN (LOSS) ALLOCATED FROM THE MASTER PORTFOLIOS
Net realized gain from investments		658,671			1,024,511
Net change in unrealized appreciation (depreciation) on investments		14,197,832			—
Net realized and unrealized gain		14,856,503			1,024,511
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	1,223,146,771		$	192,976,415

See notes to financial statements.

FINANCIAL STATEMENTS 7

Statements of Changes in Net Assets

	BlackRock Cash Funds: Institutional						BlackRock Cash Funds: Treasury
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	1,208,290,268		$	1,050,588,852		$	191,951,904		$	107,354,661
Net realized gain		658,671			2,218,840			1,024,511			134,531
Net change in unrealized appreciation (depreciation)		14,197,832			(1,677,441	)		—			—
Net increase in net assets resulting from operations		1,223,146,771			1,051,130,251			192,976,415			107,489,192
DISTRIBUTIONS TO SHAREHOLDERS(a)
Institutional		—			—			(30,289,823	)		(15,006,463	)
SL Agency		(1,208,290,268	)		(1,050,588,852	)		(161,662,081	)		(92,348,198	)
Decrease in net assets resulting from distributions to shareholders		(1,208,290,268	)		(1,050,588,852	)		(191,951,904	)		(107,354,661	)
CAPITAL SHARE TRANSACTIONS
Net increase (decrease) in net assets derived from capital share transactions		7,104,807,686			(8,828,149,128	)		5,850,717,969			1,909,166,929
NET ASSETS
Total increase (decrease) in net assets		7,119,664,189			(8,827,607,729	)		5,851,742,480			1,909,301,460
Beginning of year		47,238,154,738			56,065,762,467			6,581,657,305			4,672,355,845
End of year	$	54,357,818,927		$	47,238,154,738		$	12,433,399,785		$	6,581,657,305

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights

(For a share outstanding throughout each period)

	BlackRock Cash Funds: Institutional
	SL Agency
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	1.0001		$	1.0001		$	1.0002		$	1.00		$	1.00
Net investment income		0.0238			0.0206			0.0121			0.0058			0.0019
Net realized and unrealized gain (loss)		0.0003			0.0000	(a)		(0.0001	)		0.0003			0.0000	(a)
Net increase from investment operations		0.0241			0.0206			0.0120			0.0061			0.0019
Distributions(b)
From net investment income		(0.0238	)		(0.0206	)		(0.0121	)		(0.0058	)		(0.0019	)
From net realized gain		—			—			(0.0000	)(c)		(0.0001	)		(0.0000	)(c)
Total distributions		(0.0238	)		(0.0206	)		(0.0121	)		(0.0059	)		(0.0019	)
Net asset value, end of year	$	1.0004		$	1.0001		$	1.0001		$	1.0002		$	1.00
Total Return(d)
Based on net asset value		2.43	%		2.08	%		1.21	%		0.61	%		0.19	%
Ratios to Average Net Assets(e)(f)
Total expenses		0.09	%		0.09	%		0.09	%		0.09	%		0.09	%
Total expenses after fees waived and/or reimbursed		0.09	%		0.09	%		0.09	%		0.09	%		0.09	%
Net investment income		2.36	%		2.05	%		1.23	%		0.58	%		0.19	%
Supplemental Data
Net assets, end of year (000)	$	54,357,819		$	47,238,155		$	56,065,762		$	41,189,027		$	40,443,595

^(a)  Amount is less than $0.00005 per share.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.00005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived, the expense ratios were as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Expense ratios		0.03	%		0.03	%		0.03	%		0.03	%		0.03	%

See notes to financial statements.

FINANCIAL HIGHLIGHTS 9

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Cash Funds: Treasury
	Institutional
	Year Ended December 31,									Period from 06/06/16 (a) to 12/31/16			Period from 01/01/15 to 12/31/15 (b)
	2019			2018			2017
Net asset value, beginning of period	$	1.00		$	1.00		$	1.00		$	1.00		$	1.00
Net investment income		0.0210			0.0175			0.0079			0.0015			0.0000	(c)
Net realized gain		0.0000	(c)		0.0000	(c)		0.0000	(c)		0.0001			0.0000	(c)
Net increase from investment operations		0.0210			0.0175			0.0079			0.0016			0.0000
Distributions(d)
From net investment income		(0.0210	)		(0.0175	)		(0.0079	)		(0.0015	)		(0.0000	)(e)
From net realized gain		(0.0000	)(e)		—			(0.0000	)(e)		(0.0001	)		(0.0000	)(e)
Total distributions		(0.0210	)		(0.0175	)		(0.0079	)		(0.0016	)		(0.0000	)
Net asset value, end of period	$	1.00		$	1.00		$	1.00		$	1.00		$	1.00
Total Return(f)
Based on net asset value		2.12	%		1.76	%		0.79	%		0.16	%(g)		0.00	%
Ratios to Average Net Assets(h)(i)
Total expenses		0.12	%		0.12	%		0.12	%		0.12	%(j)		0.12	%
Total expenses after fees waived and/or reimbursed		0.12	%		0.12	%		0.12	%		0.12	%(j)		0.11	%
Net investment income		2.06	%		1.76	%		0.93	%		0.29	%(j)		0.01	%
Supplemental Data
Net assets, end of period (000)	$	1,813,191		$	1,182,627		$	467,589		$	80,257		$	—	(b)

^(a)  Recommencement of operations.

^(b)  There were no Institutional shares outstanding as of the year ended December 31, 2015.

^(c)  Amount is less than $0.00005 per share.

^(d)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(e)  Amount is greater than $(0.00005) per share.

^(f)  Where applicable, assumes the reinvestment of distributions.

^(g)  Aggregate total return.

^(h)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

⁽ⁱ⁾  Includes the Fund’s share of the Master Portfolio’s allocated fees waived, the expense ratios were as follows:

	Year Ended December 31,									Period from 06/06/16 (a) to 12/31/16			Period from 01/01/15 to 12/31/15 (b)
	2019			2018			2017
Expense ratios		0.03	%		0.03	%		0.03	%		0.03	%		0.03	%

^(j)  Annualized.

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Cash Funds: Treasury (continued)
	SL Agency
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	1.00		$	1.00		$	1.00		$	1.00		$	1.00
Net investment income		0.0213			0.0178			0.0082			0.0029			0.0003
Net realized gain		0.0000	(a)		0.0000	(a)		0.0000	(a)		0.0001			0.0000	(a)
Net increase from investment operations		0.0213			0.0178			0.0082			0.0030			0.0003
Distributions(b)
From net investment income		(0.0213	)		(0.0178	)		(0.0082	)		(0.0029	)		(0.0003	)
From net realized gain		(0.0000	)(c)		—			(0.0000	)(c)		(0.0001	)		(0.0000	)(c)
Total distributions		(0.0213	)		(0.0178	)		(0.0082	)		(0.0030	)		(0.0003	)
Net asset value, end of year	$	1.00		$	1.00		$	1.00		$	1.00		$	1.00
Total Return(d)
Based on net asset value		2.15	%		1.79	%		0.82	%		0.30	%		0.03	%
Ratios to Average Net Assets(e)(f)
Total expenses		0.09	%		0.09	%		0.09	%		0.09	%		0.09	%
Total expenses after fees waived and/or reimbursed		0.09	%		0.09	%		0.09	%		0.09	%		0.09	%
Net investment income		2.10	%		1.78	%		0.85	%		0.29	%		0.03	%
Supplemental Data
Net assets, end of year (000)	$	10,620,209		$	5,399,030		$	4,204,767		$	3,570,576		$	2,154,574

^(a)  Amount is less than $0.00005 per share.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.00005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived, the expense ratios were as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Expense ratios		0.03	%		0.03	%		0.03	%		0.03	%		0.03	%

See notes to financial statements.

FINANCIAL HIGHLIGHTS 11

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. The following, each of which is a series of the Trust, are referred to herein collectively as the “Funds” or individually as a “Fund”:

Fund Name	Herein Referred To As	Diversification Classification
BlackRock Cash Funds: Institutional	Institutional	Diversified
BlackRock Cash Funds: Treasury	Treasury	Diversified

Each Fund seeks to achieve its investment objective by investing all of its assets in a corresponding series of Master Investment Portfolio (“MIP”): Money Market Master Portfolio and Treasury Money Market Master Portfolio (each, a “Master Portfolio” and together, the “Master Portfolios”). MIP is an affiliate of the Trust. Each Master Portfolio has the same investment objective and strategies as its corresponding Fund. The value of each Fund’s investment in its corresponding Master Portfolio reflects the Fund’s proportionate interest in the net assets of the Master Portfolio. The performance of each Fund is directly affected by the performance of the Master Portfolios. At December 31, 2019, the percentage of each Master Portfolio owned by its corresponding Fund was 100% for Institutional and 91% for Treasury. The financial statements of the Master Portfolios, including the Schedules of Investments, are included elsewhere in this report and should be read in conjunction with the Funds’ financial statements.

Institutional only offers SL Agency share class and is only available for certain eligible investors. Treasury offers multiple classes of shares. Institutional, Select, SL Agency, Capital, Premium and Trust Shares are sold without a sales charge and only to certain eligible investors. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, and differ principally with respect to administration fees. The Board of Trustees of the Trust and Board of Directors of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

Treasury operates as a “government money market fund” under Rule2a-7 under the 1940 Act. The Fund is not subject to liquidity fees or temporary suspensions of redemptions due to declines in the Fund’s weekly liquid assets.

With respect to Institutional, the Board is permitted to impose a liquidity fee of up to 2% on the value redeemed or temporarily restrict redemptions from Institutional for up to 10 business days during a 90 day period, in the event that Institutional’s weekly liquid assets fall below certain thresholds.

The Funds, together with certain other affiliated registered investment companies are included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. Each Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from the Master Portfolios are accounted for on a trade date basis. The Funds record their proportionate share of the Master Portfolios’ income, expenses and realized and unrealized gains and losses on a daily basis. In addition, the Funds accrue their own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions from net investment income are declared daily and paid monthly. Distributions of capital gains are distributed at least annually and are recorded on theex-dividend dates. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

Liquidity Fees: Any liquidity fees imposed on the value of shares redeemed in the event that Institutional’s weekly liquid assets fall below certain thresholds are recorded aspaid-in-capital. The liquidity fees are collected and retained by Institutional for the benefit of Institutional’s remaining shareholders.

Indemnifications:In the normal course of business, a Fund enters into contracts that contain a variety of representations that provide general indemnification. A Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against a Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to a Fund or its classes are charged to that Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by the BlackRock Advisors, LLC (the “Administrator”), are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the Funds and other shared expenses prorated to the Funds are allocated daily to each class based on their relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies:Each Fund’s policy is to value its financial instruments at fair value. Each Fund records its investment in the Master Portfolio at fair value based on the Funds’ proportionate interest in the net assets of the Master Portfolio. Valuation of securities held by the Master Portfolio is discussed in Note 3 of the Master Portfolios’ Notes to Financial Statements, which are included elsewhere in this report.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration:The Trust, on behalf of the Funds, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL, has agreed to bear all of the Funds’ ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Funds. BAL is entitled to receive for these administrative services an annual fee based on the average daily net assets of each Fund as follows:

	Institutional			Treasury
Capital		N/A			0.07	(a)
Institutional		N/A			0.05
Premium		N/A			0.10	(a)
Select		N/A			0.15	(a)
SL Agency		0.02	%		0.02
Trust		N/A			0.38	(a)

^(a)  No shares outstanding as of December 31, 2019.

From time to time, BAL may waive such fees in whole or in part. Any such waiver will reduce the expenses of the Funds and, accordingly, have a favorable impact on their performance. BAL may delegate certain of its administration duties tosub-administrators.

For the year ended December 31, 2019, the following table shows the class specific administration fees borne directly by each class of each Fund:

	Institutional		Treasury
Capital		N/A	$	—	(a)
Institutional		N/A		735,070
Premium		N/A		—	(a)
Select		N/A		—	(a)
SL Agency	$	10,210,480		1,542,986
Trust		N/A		—	(a)
	$	10,210,480	$	2,278,056

^(a)  No shares outstanding as of December 31, 2019.

As of December 31, 2019, the only investors for the SL Agency Shares of Institutional are investment companies for which (i) BFA, BlackRock Institutional Trust Company, N.A. (“BTC”), or an affiliate provides investment advisory or administration services, or (ii) BTC acts as securities lending agent and which have directed BTC on their behalf to invest securities lending cash collateral in SL Agency Shares of Institutional. Affiliated shareholders in the SL Agency Shares of the Funds represent a significant portion of the outstanding shares and net assets of Institutional and Treasury.

Distribution Fees:The Trust, on behalf of the Funds, entered into a Distribution Agreement and a Distribution Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Shareholders of Capital, Institutional, Premium, Select, SL Agency and Trust Shares of the Funds do not pay any fees for distribution services.

Expense Waivers and Reimbursements:BAL contractually agreed to waive a portion of its administration fees equal to the annual rate of 0.02% of Select Shares average daily net assets through April 30, 2020.

The fees and expenses of the Funds’ Independent Trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Trust’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Funds. BAL has contractually agreed to reimburse the Funds or provide an offsetting credit against the administration fees paid by the Funds in an amount equal to these independent expenses through April 30, 2020. For the year ended December 31, 2019, the amounts waived and/or reimbursed were as follows:

Institutional	$	10,975
Treasury		11,033

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), each Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by each Fund’s investment policies and restrictions. Each Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Funds did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock or its affiliates.

NOTESTO FINANCIAL STATEMENTS 13

Notes to Financial Statements  (continued)

5. INCOME TAX INFORMATION

It is each Fund’s policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

Each Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on each Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on each Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Funds as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Funds’ financial statements.

The tax character of distributions paid was as follows:

	Institutional		Treasury
Ordinary income
12/31/19	$	1,208,290,268	$	191,951,904
12/31/18		1,050,588,852		107,354,661
12/31/19	$	1,208,290,268	$	191,951,904
12/31/18	$	1,050,588,852	$	107,354,661

As of December 31, 2019, the tax components of accumulated earnings were as follows:

	Institutional		Treasury
Undistributed ordinary income	$	4,174,593	$	1,459,632
Net unrealized gains (losses)		13,583,582		—
Undistributed capital gains		—		6,298
	$	17,758,175	$	1,465,930

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class of Institutional were as follows:

	Year Ended 12/31/19					Year Ended 12/31/18
Institutional	Shares			Amount		Shares			Amount
SL Agency
Shares sold		235,025,468,617		$	235,125,900,276		203,052,501,589		$	203,087,934,988
Shares issued in reinvestment of distributions		—			—		—			—
Shares redeemed		(227,923,910,156	)		(228,021,092,590)		(211,878,989,332	)		(211,916,084,116	)
Net increase (decrease)		7,101,558,461		$	7,104,807,686		(8,826,487,743	)	$	(8,828,149,128	)
Total Net Increase (Decrease)		7,101,558,461		$	7,104,807,686		(8,826,487,743	)	$	(8,828,149,128	)

The number of shares sold, reinvested and redeemed corresponds to the net proceeds from the sale of shares, reinvestment of all distributions and cost of shares redeemed, respectively, since shares are sold and redeemed at $1.00 per share for Treasury.

Transactions in capital shares for each class of Treasury were as follows:

Treasury	Year Ended 12/31/19			Year Ended 12/31/18
Institutional
Shares sold		9,317,651,619			5,279,725,471
Shares issued in reinvestment of distributions		14,519,118			8,579,680
Shares redeemed		(8,701,741,219	)		(4,573,315,565	)
Net increase		630,429,518			714,989,586
SL Agency
Shares sold		199,887,588,923			116,642,630,716
Shares issued in reinvestment of distributions		6,379,009			2,789,720
Shares redeemed		(194,673,679,481	)		(115,451,243,093	)
Net increase		5,220,288,451			1,194,177,343
Total Net Increase		5,850,717,969			1,909,166,929

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

7. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Funds through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 15

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of

BlackRock Funds III and Shareholders of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Treasury

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities of BlackRock Cash Funds: Institutional and BlackRock Cash Funds: Treasury (two of the series constituting BlackRock Funds III, hereafter collectively referred to as the “Funds”) as of December 31, 2019, the related statements of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the periods indicated therein (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Funds as of December 31, 2019, the results of each of their operations for the year then ended, the changes in each of their net assets for each of the two years in the period ended December 31, 2019 and each of the financial highlights for each of the periods indicated therein in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinions

These financial statements are the responsibility of the Funds’ management. Our responsibility is to express an opinion on the Funds’ financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Funds in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolios. We believe that our audits provide a reasonable basis for our opinions.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 14, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

Important Tax Information  (Unaudited)

The following information is provided with respect to the ordinary income distributions paid by Institutional and Treasury for the taxable year ended December 31, 2019:

Interest-Related Dividends and Qualified Short-Term Capital Gains for Non-U.S. Residents (a)
	Months Paid
	January — December 2019
Institutional	85.35%
Treasury	100.00
Federal Obligation Interest (b)
Institutional	0.86%
Treasury	46.02

^(a)  Represents the portion of the taxable ordinary dividends eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations.

^(b)  The law varies in each state as to whether and what percentage of dividend income attributable to Federal obligations is exempt from state income tax. We recommend that you consult your tax advisor to determine if any of the dividends you received is exempt from state income taxes.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Master Portfolio Information  as of December 31, 2019

Portfolio Composition

Money Market Master Portfolio	Percent of Net Assets
Certificates of Deposit		33	%
Repurchase Agreements		29
Commercial Paper		23
Time Deposits		8
U.S. Treasury Obligations		4
Municipal Bonds		2
Corporate Bonds		1
Other Assets and Liabilities		—	(a)

^(a)  Represents less than 1%.

Treasury Money Market Master Portfolio	Percent of Net Assets
Repurchase Agreements		53	%
U.S. Treasury Obligations		48
Other Assets and Liabilities		(1	)

MASTER PORTFOLIO INFORMATION 17

Schedule of Investments December 31, 2019 Money Market Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Certificates of Deposit — 33.2%
Domestic — 3.0%
Bank of America NA, 1.83%, 03/16/20(a)		USD   236,000	$	236,000,000
Goldman Sachs Bank USA(b):
(SOFR + 0.25%), 1.79%, 06/11/20		100,000		99,924,466
(SOFR + 0.25%), 1.79%, 06/25/20		46,000		46,001,019
(SOFR + 0.25%), 1.79%, 06/29/20		174,000		173,999,783
(SOFR + 0.40%), 1.93%, 11/05/20		50,000		49,991,172
HSBC Bank USA NA(b):
(3 mo. LIBOR US + 0.12%), 2.04%, 08/26/20		101,500		101,512,733
(3 mo. LIBOR US + 0.22%), 2.13%, 12/04/20		155,000		155,000,000
Wells Fargo Bank NA(b):
(3 mo. LIBOR US + 0.21%), 2.24%, 02/07/20		278,500		278,562,651
(1 mo. LIBOR US + 0.22%), 1.96%, 07/15/20		484,500		484,562,496
Total Domestic — 3.0% (Cost — $1,625,500,000)				1,625,554,320
Euro — 3.0%
Bank of Montreal, London:
0.01%, 01/02/20		400,000		400,000,000
2.00%, 01/06/20		200,000		200,000,000
Credit Industriel et Commercial, London:
0.01%, 02/10/20		250,000		249,553,785
0.01%, 03/13/20		400,000		398,633,100
Nationwide Building Society, 2.01%, 01/07/20		345,000		345,000,000
Sumitomo Trust & Banking Co. Ltd., London, 2.18%, 03/26/20(c)		65,000		64,703,997
Total Euro — 3.0% (Cost — $1,657,044,589)				1,657,890,882
Yankee(d) — 27.2%
Australia & New Zealand Banking Group Ltd., New York, 2.70%, 03/31/20		109,250		109,469,679
Banco Santander SA, New York:
(1 mo. LIBOR US + 0.24%), 1.95%, 01/06/20(b)		200,000		200,014,032
1.91%, 02/14/20		250,000		250,046,967
Bank of Montreal, Chicago:
2.10%, 01/03/20		110,000		110,004,644
(1 mo. LIBOR US + 0.42%), 2.16%, 01/17/20(b)		349,000		349,078,874
(Fed Funds Rate + 0.35%), 1.90%, 08/05/20(b)		100,000		100,034,952
(3 mo. LIBOR US + 0.14%), 2.04%, 11/18/20(b)		75,000		75,027,746
(3 mo. LIBOR US + 0.13%), 2.03%, 01/04/21(b)		150,000		149,998,599
Barclays Bank PLC, New York:
2.10%, 05/01/20		394,100		394,341,477
2.05%, 06/22/20		322,000		322,134,119
Bayerische Landesbank, New York:
2.00%, 01/02/20		400,000		399,999,040
2.12%, 02/19/20		250,000		250,088,455
BNP Paribas SA, New York(b):
(3 mo. LIBOR US + 0.20%), 2.21%, 10/09/20		327,750		327,824,301
(3 mo. LIBOR US + 0.19%), 2.19%, 10/16/20		200,000		200,030,918
Credit Agricole CIB, New York:
2.76%, 03/18/20		244,750		245,197,166
(3 mo. LIBOR US + 0.13%), 2.04%, 03/20/20(b)		306,500		306,577,354
(1 mo. LIBOR US + 0.25%), 2.05%, 05/29/20(b)		200,000		200,016,706
Credit Industriel et Commercial, New York, (3 mo. LIBOR US + 0.14%), 2.04%, 12/04/20(b)		246,000		246,000,000
Credit Suisse AG, New York:
(SOFR + 0.38%), 1.92%, 03/06/20(b)		59,000		59,021,105
2.70%, 05/01/20		308,500		309,248,264
(SOFR + 0.37%), 1.91%, 05/22/20(b)		150,000		150,046,152
(SOFR + 0.26%), 1.80%, 06/12/20(b)		62,000		61,977,745
(SOFR + 0.30%), 1.84%, 06/19/20		125,000		125,005,726

Security	Par (000)		Value
Yankee(d) (continued)
Credit Suisse AG, New York (continued):
(SOFR + 0.48%), 2.02%, 10/02/20(b)		USD   200,000	$	200,105,846
(3 mo. LIBOR US + 0.23%), 2.12%, 12/30/20(b)		200,000		199,998,686
Landesbank Baden-Wurttemberg, New York, 2.00%, 01/02/20		500,000		499,999,080
Lloyds Bank Corporate Markets PLC, New York:
2.30%, 01/21/20		200,000		200,058,938
(3 mo. LIBOR US + 0.17%), 2.17%, 04/17/20(b)		171,500		171,534,194
(3 mo. LIBOR US + 0.17%), 2.17%, 04/30/20(b)		250,000		250,000,000
2.00%, 05/01/20		142,000		142,053,754
(3 mo. LIBOR US + 0.14%), 2.05%, 05/06/20(b)		150,000		150,000,000
Mitsubishi UFJ Trust & Banking Corp., New York, (3 mo. LIBOR US + 0.08%), 2.00%, 05/27/20(b)		98,000		98,011,308
Mizuho Bank Ltd., New York, (3 mo. LIBOR US + 0.10%), 2.04%, 10/01/20(b)		300,000		300,000,000
MUFG Bank Ltd., New York:
(3 mo. LIBOR US + 0.18%), 2.09%, 02/24/20(b)		351,000		351,078,687
2.72%, 02/24/20		419,500		420,064,546
(3 mo. LIBOR US + 0.18%), 2.10%, 02/27/20(b)		250,000		250,059,355
2.66%, 04/23/20		196,750		197,214,546
(3 mo. LIBOR US + 0.14%), 2.04%, 05/11/20(b)		168,000		168,053,369
1.95%, 10/15/20		100,000		100,049,963
Natixis SA, New York:
2.72%, 04/03/20		368,500		369,197,935
(1 mo. LIBOR US + 0.26%), 2.00%, 05/15/20(b)		144,000		144,035,089
(1 mo. LIBOR US + 0.26%), 1.97%, 05/29/20(b)		400,000		400,117,680
Nordea Bank AB, New York, 2.35%, 06/03/20		247,000		247,522,464
Nordea Bank Abp, New York(b):
(3 mo. LIBOR US + 0.14%), 2.10%, 09/28/20		300,000		300,087,915
(3 mo. LIBOR US + 0.16%), 2.16%, 10/16/20		70,000		70,027,116
Norinchukin Bank, New York:
2.27%, 01/21/20		230,000		230,065,212
2.20%, 01/29/20		125,000		125,035,358
1.94%, 04/29/20		125,000		125,018,046
Oversea-Chinese Banking Corp. Ltd., New York, 1.95%, 04/16/20		100,000		100,003,266
Skandinaviska Enskilda Banken AB, New York(b):
(3 mo. LIBOR US + 0.15%), 2.24%, 10/02/20		25,000		25,009,275
(3 mo. LIBOR US + 0.15%), 2.24%, 10/05/20		200,000		200,075,224
Standard Chartered Bank, New York:
1.94%, 02/18/20		190,000		190,028,245
(Fed Funds Rate + 0.35%), 1.90%, 02/21/20(b)		145,000		145,014,928
1.99%, 05/01/20		264,000		264,083,046
Sumitomo Mitsui Banking Corp, New York, (3 mo. LIBOR US + 0.07%), 2.03%, 06/30/20(b)		367,500		367,499,761
Sumitomo Mitsui Trust Bank Ltd., New York(b):
(3 mo. LIBOR US + 0.24%), 2.24%, 01/15/20		418,000		418,028,658
(3 mo. LIBOR US + 0.19%), 2.10%, 02/25/20		525,000		525,127,643
(3 mo. LIBOR US + 0.20%), 2.10%, 05/18/20		245,000		245,137,124
(3 mo. LIBOR US + 0.17%), 2.11%, 07/27/20		151,400		151,433,774
Svenska Handelsbanken, New York, (3 mo. LIBOR US + 0.15%), 2.24%, 10/02/20(b)		200,000		200,074,196
Toronto-Dominion Bank, New York:
(Fed Funds Rate + 0.30%), 1.85%, 02/27/20(b)		204,000		204,011,351
2.17%, 07/29/20		265,000		265,434,237
(Fed Funds Rate + 0.35%), 1.90%, 08/06/20(b)		50,000		50,011,656
(3 mo. LIBOR US + 0.19%), 2.14%, 09/28/20(b)		589,000		589,428,786
Westpac Banking Corp., New York, (3 mo. LIBOR US + 0.15%), 2.04%, 12/09/20(b)		200,000		200,017,886
Total Yankee — 27.2% (Cost — $14,784,026,078)				14,790,992,164
Total Certificates of Deposit — 33.2% (Cost — $18,066,570,667)				18,074,437,366

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Money Market Master Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Commercial Paper — 23.3%
Alpine Securitization LLC, (1 mo. LIBOR US + 0.17%), 1.96%, 06/25/20(b)(e)		$	55,250	$	55,249,976
Antalis SA, 2.29%, 01/22/20(c)			97,000		96,892,530
Atlantic Asset Securitization LLC, 2.06%, 01/17/20(c)			100,000		99,916,936
Banco Santander SA, 1.98%, 06/26/20(c)			248,500		246,240,432
Banque ET Caisse, 2.22%, 04/14/20(c)			100,000		99,477,917
Bennington Sark Cap Co., 2.00%, 01/02/20(c)			883,000		882,910,181
BPCE(c):
1.94%, 07/31/20			197,000		194,750,424
2.04%, 12/23/20			456,250		447,493,294
Canadian Imperial Bank of Commerce:
2.00%, 01/02/20(c)			290,000		289,972,804
(1 mo. LIBOR US + 0.25%), 2.05%, 12/31/20(b)			100,000		100,000,000
Cancara Asset Securitisation LLC, 1.95%, 06/09/20(c)	��		65,600		65,063,118
Chesham Finance Ltd., 1.60%, 01/07/20(c)			250,000		249,944,445
Collateralized Commercial Paper Co. LLC, 2.00%, 01/06/20(c)			175,000		174,949,075
Collateralized Commercial Paper Flex Co. LLC, (3 mo. LIBOR US + 0.27%), 2.28%, 01/10/20(b)(e)			173,000		173,000,000
Commonwealth Bank of Australia, (3 mo. LIBOR US + 0.15%), 2.09%, 09/21/20(b)(e)			248,000		248,000,000
Crown Point Capital Co. LLC(b)(e):
(1 mo. LIBOR US + 0.25%), 1.96%, 02/06/20			570,000		570,000,000
(1 mo. LIBOR US + 0.38%), 2.18%, 08/28/20			90,000		90,055,239
Enbridge, Inc., 2.21%, 01/30/20(c)			252,000		251,571,600
Exelon Generation Co. LLC, 1.85%, 01/06/20(c)			70,000		69,976,958
Glencove Funding LLC,(1-Week LIBOR + 0.12%), 1.72%, 06/11/20(b)(e)			225,000		225,000,000
HSBC Bank PLC(b)(e):
(3 mo. LIBOR US + 0.09%), 1.98%, 05/07/20			100,000		100,013,497
(1 mo. LIBOR US + 0.38%), 2.17%, 09/21/20			142,000		142,050,995
(1 mo. LIBOR US + 0.40%), 2.11%, 10/06/20			233,000		233,085,061
(3 mo. LIBOR US + 0.24%), 2.27%, 10/06/20			50,000		50,041,262
(3 mo. LIBOR US + 0.23%), 2.23%, 10/13/20			284,000		284,218,214
(3 mo. LIBOR US + 0.19%), 2.10%, 12/01/20			400,000		400,143,272
ING US Funding LLC(b)(e):
(3 mo. LIBOR US + 0.09%), 2.19%, 04/01/20			278,000		278,027,283
(3 mo. LIBOR US + 0.17%), 2.10%, 09/23/20			441,000		441,031,139
(3 mo. LIBOR US + 0.20%), 2.17%, 10/19/20			274,000		274,064,417
Kells Funding LLC, 2.06%, 03/04/20(c)			96,000		95,691,947
Landesbank Baden-Wurttemberg, New York, 1.95%, 01/03/20(c)			107,800		107,786,183
Lexington Parker Capital Co. LLC, 2.00%, 01/02/20(c)			330,000		329,968,082
Macquarie Bank Ltd.(b)(e):
(3 mo. LIBOR US + 0.12%), 2.01%, 05/07/20			131,000		131,031,241
(3 mo. LIBOR US + 0.13%), 2.03%, 05/08/20			200,000		200,000,000
(3 mo. LIBOR US + 0.20%), 2.10%, 12/04/20			248,000		248,000,000
National Security Clearing Corp., 3.09%, 01/02/20(c)			250,000		249,978,903
Nationwide Building Society(c):
2.02%, 04/01/20(e)			169,000		168,162,135
1.96%, 05/26/20			100,000		99,200,483
Nissan Motor Acceptance Corp., 2.00%, 01/07/20(c)			242,000		241,914,359
Nordea Bank AB(c):
2.68%, 04/27/20			131,000		130,227,100
2.68%, 04/29/20			300,000		298,200,000
Oversea-Chinese Banking Corp. Ltd., 1.94%, 10/19/20(c)			171,000		168,422,479
Ridgefield Funding Co. LLC(c):
2.05%, 02/20/20			237,000		236,378,863
2.07%, 02/24/20			35,382		35,281,997
Royal Bank of Canada(b)(e):
(3 mo. LIBOR US + 0.21%), 2.25%, 01/07/20			96,000		96,002,564
(SOFR + 0.51%), 2.05%, 01/09/20			283,500		283,535,508
(Fed Funds Rate + 0.30%), 1.85%, 03/16/20			125,000		125,012,539

Security	Par (000)		Value
Commercial Paper (continued)
Royal Bank of Canada (continued):
(Fed Funds Rate + 0.28%), 1.83%, 06/12/20	$	438,000	$	438,018,322
Shell International Finance BV(c):
2.09%, 06/25/20		40,750		40,389,363
2.09%, 06/30/20		43,000		42,608,482
Toyota Credit Canada, Inc.(b):
(1 mo. LIBOR US + 0.17%), 1.87%, 02/20/20		50,000		50,000,000
(1 mo. LIBOR US + 0.17%), 1.87%, 02/28/20		100,000		100,000,000
Toyota Motor Credit Corp.(b):
(3 mo. LIBOR US + 0.03%), 2.03%, 01/07/20		41,500		41,500,050
(3 mo. LIBOR US + 0.03%), 2.03%, 01/08/20		200,000		200,000,000
(1 mo. LIBOR US + 0.17%), 1.87%, 02/27/20		231,000		231,043,899
(1 mo. LIBOR US + 0.21%), 1.92%, 05/05/20		46,000		46,000,000
UBS AG:
2.32%, 04/24/20(c)		241,500		240,092,089
(3 mo. LIBOR US + 0.09%), 2.00%, 05/28/20(b)(e)		200,000		200,000,000
VW Credit, Inc., 1.97%, 01/07/20(c)		193,000		192,931,699
Westpac Banking Corp.(b)(e):
(3 mo. LIBOR US + 0.15%), 2.16%, 01/10/20		224,000		224,007,439
(Fed Funds Rate + 0.26%), 1.81%, 06/08/20		182,000		182,007,471
(3 mo. LIBOR US + 0.15%), 2.04%, 11/25/20		400,000		400,141,196
Total Commercial Paper — 23.3% (Cost — $12,703,402,535)				12,706,674,462
Corporate Bonds — 1.0%
Auto Components — 0.2%
American Honda Finance Corp, (3 mo. LIBOR US + 0.09%), 1.99%, 05/13/20(b)		131,000		131,008,715
Banks — 0.1%
Citibank NA, 2.10%, 06/12/20		64,805		64,837,058
Capital Markets — 0.2%
CPPIB Capital, Inc, (SOFR + 0.32%), 1.86%, 12/10/20(b)(e)		92,750		92,760,816
Consumer Finance — 0.2%
Caterpillar Financial Services Corp, (3 mo. LIBOR US + 0.10%), 2.00%, 06/19/20(b)		79,000		79,007,198
Diversified Financial Services — 0.1%
UBS AG, Stamford, 2.35%, 03/26/20		50,000		50,055,017
Industrial Conglomerates — 0.2%
Siemens Financieringsmaatschappij NV, (3 mo. LIBOR US + 0.34%), 2.23%, 03/16/20(b)(e)		108,145		108,194,972
Total Corporate Bonds — 1.0% (Cost — $525,678,003)				525,863,776
Municipal Bonds — 1.6%
Delaware — 0.0%
Rib Floater Trust Various States, RB, Series19-W, 2.15%, 02/04/20(e)(f)		17,095		17,095,000
Florida — 0.1%
Taxable Municipal Funding Trust, RB, VRDN, 1.71%, 01/07/20(e)(f)		30,480		30,480,000
Maine — 0.1%
Maine State Housing Authority, Refunding RB, VRDN, 1.71%, 01/07/20(f)		51,000		51,000,000
Minnesota — 0.1%
Taxable Municipal Funding Trust, RB, VRDN, 2.15%, 01/07/20(e)(f)		33,995		33,995,000

SCHEDULES OF INVESTMENTS 19

Schedule of Investments  (continued) December 31, 2019 Money Market Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
New Hampshire — 0.0%
New Hampshire Business Finance Authority, RB, DrawDown-CJ FMB, Series A, 1.92%, 01/07/20(e)(f)	$	12,500	$	12,500,000
New Jersey — 0.5%
Taxable Municipal Funding Trust, Refunding RB, VRDN(e)(f):
1.71%, 01/07/20		17,470		17,470,000
Taxable, Series2019-014, 2.15%, 01/07/20		242,515		242,515,000
				259,985,000
New York — 0.7%
Jets Stadium Development LLC(e)(f):
1.85%, 01/07/20		39,855		39,855,000
1.85%, 01/07/20		29,600		29,600,000
VRDN, SeriesA-4B, 1.85%, 01/07/20		2,500		2,500,000
Jets Stadium Finance Secured, 1.85%, 01/07/20(e)(f)		121,295		121,295,000
Rib Floater Trust Various States, RB, VRDN, 2.15%, 02/04/20(e)(f)		18,705		18,705,000
Taxable Municipal Funding Trust, RB(e)(f):
(AGM), VRDN, 1.71%, 01/07/20		33,080		33,080,000
VRDN, 2.15%, 02/04/20		61,585		61,585,000
VRDN, 2.15%, 02/04/20		6,300		6,300,000
VRDN, 2.15%, 01/07/20		70,915		70,915,000
Taxable Municipal Funding Trust, Refunding RB, VRDN, Taxable, Series2019-008, 2.15%, 01/07/20(e)(f):		7,140		7,140,000
				390,975,000
Texas — 0.0%
Taxable Municipal Funding Trust, RB, Series2018-001, 1.71%, 01/07/20(e)(f):		18,880		18,880,000
West Virginia — 0.1%
Taxable Municipal Funding Trust, RB, VRDN, 1.71%, 01/07/20(e)(f):		47,840		47,840,000
Total Municipal Bonds — 1.6% (Cost — $862,750,000)				862,750,000
Time Deposits — 7.7%
Bank of Nova Scotia:
1.70%, 01/02/20		1,000,000		1,000,000,000
1.60%, 01/07/20		275,000		275,000,000
Credit Agricole CIB, New York:
1.53%, 01/02/20		126,000		126,000,000
1.75%, 01/03/20		550,000		550,000,000
Landesbank Hessen-Thueringen Girozentrale, 1.55%, 01/02/20		84,000		84,000,000
Mizuho Bank Ltd., New York, 1.58%, 01/02/20		880,000		880,000,000
National Bank of Canada, 1.70%, 01/03/20		300,000		300,000,000
Natixis, SA, 1.53%, 01/02/20		100,000		100,000,000
Royal Bank of Canada, New York:
1.45%, 01/02/20		126,000		126,000,000
1.55%, 01/02/20		775,000		775,000,000
Total Time Deposits — 7.7% (Cost — $4,216,000,000)				4,216,000,000
U.S. Treasury Obligations — 3.8%
U.S. Treasury Bills(c):
1.61%, 01/21/20		250,000		249,806,680
1.87%, 03/12/20		270,000		269,218,536
U.S. Treasury Notes(b):
(3 mo.Treasury money market yield + 0.22%), 1.75%, 07/31/21		280,000		280,119,826

Security	Par (000)		Value
U.S. Treasury Obligations (continued)
(3 mo.Treasury money market yield + 0.30%), 1.83%, 10/31/21	$	1,276,000	$	1,278,260,141
Total U.S. Treasury Obligations — 3.8% (Cost — $2,075,146,000)				2,077,405,183
Total Repurchase Agreements — 29.0% (Cost — $15,777,500,751)				15,777,500,751
Total Investments — 99.6% (Cost — $54,227,047,956)*				54,240,631,538
Other Assets Less Liabilities — 0.4%				203,054,179
Net Assets — 100.0%			$	54,443,685,717

* Cost for U.S. federal income tax purposes.

^(a)  Variable or floating rate security, which interest rate adjusts periodically based on changes in current interest rates and prepayments on the underlying pool of assets. Rate shown is the rate in effect as of period end.

^(b)  Variable rate security. Rate shown is the rate in effect as of period end.

^(c)  Rates are discount rates or a range of discount rates as of period end.

^(d)  Issuer is a U.S. branch of a foreign domiciled bank.

^(e)  Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

^(f)  Variable rate security. Rate as of period end and maturity is the date the principal owed can be recovered through demand.

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Money Market Master Portfolio

Repurchase Agreements

	Repurchase Agreements													Collateral
Counterparty	Coupon Rate			Purchase Date		Maturity Date		Par (000)		At Value (000)		Proceeds Including Interest		Position	Original Par		Position Received At Value
Barclays Capital, Inc.		1.66	%(a)		12/31/19		01/02/20	$	144,000	$	144,000	$	44,013,280	Corporate Debt/Obligation, 0.00% to 9.00%, due 1/07/21 to 6/01/67	$	137,855,000	$	151,200,585
		1.69	(a)		12/31/19		01/02/20		109,000		109,000		109,010,234	Corporate Debt/Obligation, 2.13% to 7.50%, due 11/03/20 to 12/31/49		105,307,573		114,450,000
		1.89	(a)		12/31/19		01/02/20		137,000		137,000		137,014,385	Corporate Debt/Obligation, 2.89% to 9.38%, due 4/15/20 to 3/01/50		157,149,205		153,356,543
		1.99	(a)		12/31/19		04/04/20		135,000		135,000		135,708,938	Corporate Debt/Obligation, 2.60% to 5.75%, due 9/01/20 to 9/23/49		132,441,332		141,750,000
Total Barclays Capital, Inc.										$	525,000						$	560,757,128
BNP Paribas Securities Corp.		1.64	(a)		12/31/19		01/02/20		355,000		355,000		355,032,344	U.S. Treasury Obligation, 0.00% to 7.88%, due 2/07/20 to 2/25/68		373,632,033		372,024,147
		2.21	(a)		12/31/19		04/04/20		100,000		100,000		100,583,194	Corporate Debt/Obligation, 2.08% to 11.50%, due 7/16/20 to 12/31/49		109,063,726		112,698,330
Total BNP Paribas Securities Corp.										$	455,000						$	484,722,477
Citigroup Global Markets, Inc.		1.55	(b)		12/31/19		01/02/20		13,000		13,000		13,001,119	U.S. Treasury Obligation, 0.63% to 3.63%, due 2/15/43 to 8/15/44		10,870,429		13,295,954
		1.57			12/31/19		01/02/20		97,000		97,000		97,008,461	U.S. Government Sponsored Agency Obligation, 0.00% to 8.00%, due 2/15/28 to 1/25/41		321,543,576		100,078,043
		1.59	(a)		12/31/19		01/02/20		100,000		100,000		100,008,833	U.S. Treasury Obligation, 0.00% to 2.88%, due 1/02/20 to 8/15/28		99,783,000		103,045,911
		2.30	(a)		12/31/19		04/01/20		209,000		209,000		210,228,456	Corporate Debt/Obligation, 0.00% to 7.20%, due 1/17/20 to 12/01/96		1,213,075,614		220,571,231
Total Citigroup Global Markets, Inc.										$	419,000						$	436,991,139
Credit Agricole Corp.(g)		1.55	(b)		12/31/19		01/02/20		189,000		189,000		189,016,275	U.S. Treasury Obligation, 1.25% to 2.25%, due 3/31/21 to 11/15/27		190,940,872		192,780,019
Credit Suisse Securities (USA) LLC		2.21	(a)		12/31/19		02/04/20		100,000		100,000		100,214,861	Corporate Debt/Obligation, 1.03% to 10.88%, due 8/15/20 to 10/25/59		300,875,650		108,302,266
		2.21	(a)		12/31/19		02/04/20		482,000		482,000		483,035,631	Corporate Debt/Obligation, 0.00% to 14.54%, due 8/15/20 to 10/25/59		9,608,191,365		555,687,897
Total Credit Suisse Securities (USA) LLC										$	582,000						$	663,990,163
Deutsche Bank Securities, Inc.		1.46			12/31/19		01/02/20		115,000		115,000		115,009,328	U.S. Treasury Obligation, 0.00%, due 2/15/31		145,331,600		117,300,041
		1.57			12/31/19		01/02/20		1,300,000		1,300,000		1,300,113,389	U.S. Government Sponsored Agency Obligation, 0.13% to 4.50%, due 4/15/20 to 1/01/50		1,512,074,758		1,337,132,375
Total Deutsche Bank Securities, Inc.										$	1,415,000						$	1,454,432,416
Federal Reserve Bank of New York		1.45			12/31/19		01/02/20		1,600,000		1,600,000		1,600,128,889	U.S. Treasury Obligation, 2.25% to 2.75%, due 4/30/23 to 11/15/27		1,542,019,900		1,600,128,982

SCHEDULES OF INVESTMENTS 21

Schedule of Investments  (continued) December 31, 2019 Money Market Master Portfolio

Repurchase Agreements (continued)

	Repurchase Agreements													Collateral
Counterparty	Coupon Rate			Purchase Date		Maturity Date		Par (000)		At Value (000)		Proceeds Including Interest		Position	Original Par		Position Received At Value
HSBC Securities (USA), Inc.		1.66	%(a)		12/31/19		01/02/20	$	67,000	$	67,000	$	67,006,179	Corporate Debt/Obligation, 0.13% to 6.90%, due 2/14/20 to 1/15/87	$	68,785,927	$	70,264,128
		1.74	(a)		12/31/19		01/02/20		89,500		89,500		89,508,652	Corporate Debt/Obligation, 2.22% to 7.30%, due 4/15/23 to 12/31/49		96,007,252		98,106,478
Total HSBC Securities (USA), Inc.										$	156,500						$	168,370,606
J.P. Morgan Securities LLC		1.55			12/31/19		01/02/20		502,000		502,000		502,043,228	U.S. Treasury Obligation, 0.13% to 3.00%, due 1/15/23 to 2/15/47		453,230,800		512,040,097
		1.57			12/31/19		01/02/20		435,000		435,000		435,037,942	U.S. Government Sponsored Agency Obligation, 2.50% to 7.00%, due 10/20/24 to 9/01/69		1,008,758,307		443,700,000
		1.58			12/31/19		01/02/20		74,448		74,448		74,455,064	U.S. Treasury Obligation, 1.88%, due 7/31/26		75,000,000		75,937,500
		1.58			12/31/19		01/02/20		874,088		874,088		874,164,766	U.S. Treasury Obligation, 2.88%, due 8/15/28		817,017,000		891,569,801
		1.58			12/31/19		01/02/20		270,010		270,010		270,033,872	U.S. Treasury Obligation, 2.13%, due 5/31/26		269,350,000		275,410,375
		1.58			12/31/19		01/02/20		24,663		24,663		24,665,155	U.S. Treasury Obligation, 1.88%, due 6/30/26		25,000,000		25,156,250
		1.58			12/31/19		01/02/20		580,335		580,335		580,386,437	U.S. Treasury Obligation, 3.13%, due 11/15/28		535,089,000		591,942,206
		1.58			12/31/19		01/02/20		9,033		9,033		9,033,881	U.S. Treasury Obligation, 2.13%, due 5/15/25		9,000,000		9,213,750
		1.58			12/31/19		01/02/20		395,221		395,221		395,255,280	U.S. Treasury Obligation, 3.00%, due 10/31/25		375,000,000		403,125,000
		1.58			12/31/19		01/02/20		26,287		26,287		26,289,072	U.S. Treasury Obligation, 2.88%, due 7/31/25		25,000,000		26,812,500
		1.58			12/31/19		01/02/20		656,693		656,693		656,750,290	U.S. Treasury Obligation, 2.63%, due 12/31/25		637,930,000		669,826,500
		1.58			12/31/19		01/02/20		221,769		221,769		221,788,094	U.S. Treasury Obligation, 2.63%, due 1/31/26		213,400,000		226,204,000
		1.58			12/31/19		01/02/20		33,572		33,572		33,574,822	U.S. Treasury Obligation, 2.88%, due 5/31/25		32,229,000		34,243,313
		1.58			12/31/19		01/02/20		129,602		129,602		129,612,939	U.S. Treasury Obligation, 1.63%, due 9/30/26		133,025,000		132,193,594
		1.58			12/31/19		01/02/20		431,280		431,280		431,318,028	U.S. Treasury Obligation, 1.63%, due 5/15/26		443,230,000		439,905,775
		1.64	(a)		12/31/19		01/02/20		285,000		285,000		285,025,967	U.S. Government Sponsored Agency Obligation, 0.00% to 7.50%, due 6/02/20 to 6/16/61		5,907,672,708		297,322,915
		1.66	(a)		12/31/19		01/02/20		116,000		116,000		116,010,698	Corporate Debt/Obligation, 0.00% to 7.00%, due 1/09/20 to 9/16/58		3,898,908,581		120,978,710
		1.72	(a)		12/31/19		01/02/20		90,000		90,000		90,008,600	Corporate Debt/Obligation, 0.08% to 7.93%, due 12/21/30 to 12/16/72		841,433,328		96,300,000
		1.89	(a)		12/31/19		01/02/20		90,000		90,000		90,009,450	Corporate Debt/Obligation, 1.00% to 11.00%, due 5/15/21 to 12/31/2500		523,109,875		97,260,995
		3.25			12/27/19		01/02/20		180,075		180,075		180,173,004	U.S. Treasury Obligation, 3.00%, due 11/15/44		162,726,000		183,676,973
		3.25			12/27/19		01/02/20		125,766		125,766		125,834,055	U.S. Treasury Obligation, 2.13%, due 9/30/24		125,000,000		128,281,250
		3.25			12/27/19		01/02/20		351,437		351,437		351,627,597	U.S. Treasury Obligation, 2.25%, due 12/31/24		348,875,000		358,465,980
		3.25			12/27/19		01/02/20		42,722		42,722		42,744,709	U.S. Treasury Obligation, 2.50%, due 2/15/45		41,900,000		43,576,000

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Money Market Master Portfolio

Repurchase Agreements (continued)

	Repurchase Agreements													Collateral
Counterparty	Coupon Rate			Purchase Date		Maturity Date		Par (000)		At Value (000)		Proceeds Including Interest		Position	Original Par		Position Received At Value
J.P. Morgan Securities LLC		1.76	%(a)		12/31/19		01/07/20	$	498,000	$	498,000	$	498,170,427	U.S. Government Sponsored Agency Obligation, 0.04% to 7.00%, due 8/25/22 to 9/16/61	$	2,695,946,129	$	509,805,563
		1.84	(a)		12/31/19		01/07/20		755,000		755,000		755,270,122	Corporate Debt/Obligation, 0.00% to 9.75%, due 5/15/20 to 12/17/59		3,118,665,470		811,860,801
		2.21	(a)		12/31/19		03/31/20		175,000		175,000		175,977,618	Corporate Debt/Obligation, 0.00% to 7.50%, due 9/15/20 to 11/15/61		356,960,625		189,006,132
		2.26	(a)		12/31/19		03/31/20		320,000		320,000		321,828,089	Corporate Debt/Obligation, 0.00% to 8.09%, due 3/18/21 to 3/01/78		779,663,772		344,775,558
		2.31	(a)		12/31/19		03/31/20		205,000		205,000		206,197,029	Corporate Debt/Obligation, 2.30% to 8.43%, due 11/02/20 to 6/25/59		270,313,540		220,728,784
Total J.P. Morgan Securities LLC										$	7,898,001						$	8,159,320,322
Merrill Lynch, Pierce, Fenner & Smith, Inc.		1.45			12/31/19		01/02/20		300,000		300,000		300,024,167	U.S. Treasury Obligation, 2.00%, due 4/30/24		300,861,100		306,000,003
		1.55			12/31/19		01/02/20		400,000		400,000		400,034,444	U.S. Treasury Obligation, 1.25% to 2.63%, due 10/31/21 to 12/31/25		402,336,600		408,000,036
		1.57			12/31/19		01/02/20		120,000		120,000		120,010,467	U.S. Government Sponsored Agency Obligation, 2.75% to 3.00%, due 1/25/43 to 2/20/46		127,630,397		126,000,000
		1.64	(a)		12/31/19		01/02/20		115,000		115,000		115,010,478	U.S. Government Sponsored Agency Obligation, 3.00%, due 1/01/50		116,470,507		118,450,001
		1.94	(a)		12/31/19		02/04/20		65,000		65,000		65,122,597	Corporate Debt/Obligation, 3.25% to 7.38%, due 3/15/24 to 6/25/48		58,766,121		68,250,000
		2.24	(a)		12/31/19		03/05/20		240,000		240,000		240,970,667	Corporate Debt/Obligation, 5.54% to 7.49%, due 4/25/28 to 4/25/49		287,062,356		288,000,001
Total Merrill Lynch, Pierce, Fenner & Smith, Inc.										$	1,240,000						$	1,314,700,041
Mizuho Security USA, Inc.		1.69	(a)		12/31/19		01/02/20		45,000		45,000		45,004,225	Corporate Debt/Obligation, 2.45% to 4.00%, due 6/01/34 to 9/15/69		46,325,643		48,150,001
		1.84	(a)		12/31/19		01/02/20		30,000		30,000		30,003,067	Corporate Debt/Obligation, 4.00%, due 6/15/35		29,247,079		32,100,001
		2.35	(a)		12/31/19		02/04/20		44,000		44,000		44,100,528	Corporate Debt/Obligation, 3.79% to 5.16%, due 4/10/28 to 9/15/58		46,624,935		47,080,001
Total Mizuho Security USA, Inc.										$	119,000						$	127,330,003
TD Securities (USA) LLC		1.66	(a)		12/31/19		01/02/20		75,000		75,000		75,006,917	Corporate Debt/Obligation, 1.65% to 5.40%, due 3/22/21 to 1/15/49		76,450,125		78,750,573
Wells Fargo Securities LLC		1.57			12/31/19		01/02/20		75,000		75,000		75,006,542	U.S. Government Sponsored Agency Obligation, 2.50% to 5.00%, due 1/01/32 to 3/01/49		102,748,097		77,250,000

SCHEDULES OF INVESTMENTS 23

Schedule of Investments  (continued) December 31, 2019 Money Market Master Portfolio

Repurchase Agreements (continued)

	Repurchase Agreements													Collateral
Counterparty	Coupon Rate			Purchase Date		Maturity Date		Par (000)		At Value (000)		Proceeds Including Interest		Position	Original Par		Position Received At Value
Wells Fargo Securities LLC		1.64	%		12/31/19		01/02/20	$	200,000	$	200,000	$	200,018,222	U.S. Treasury Obligation, 0.00%, due 1/06/20	$	210,225,486	$	210,000,000
		1.64	(a)		12/31/19		01/02/20		100,000		100,000		100,009,111	Corporate Debt/Obligation, 0.00%, due 1/30/20		105,243,275		105,000,000
		1.66	(a)		12/31/19		01/02/20		530,000		530,000		530,048,878	Corporate Debt/Obligation, 0.00% to 6.46%, due 2/24/20 to 5/15/62		725,037,470		559,654,023
		1.69			12/26/19		01/02/20		70,000		70,000		70,023,003	Corporate Debt/Obligation, 0.00%, due 1/27/20		72,717,103		72,342,296
		1.69			12/27/19		01/03/20		71,000		71,000		71,023,331	Corporate Debt/Obligation, 0.00%, due 1/21/20		74,717,968		74,478,346
		2.13			12/20/19		03/20/20		58,000		58,000		58,312,282	Corporate Debt/Obligation, 2.75%, due 3/15/23		58,507,577		60,900,001
Total Wells Fargo Securities LLC										$	1,104,000						$	1,159,624,666
										$	15,777,501						$	16,342,156,538

^(a)  Variable rate security. Rate as of period end and maturity is the date the principal owed can be recovered through demand.

^(b)  Traded in a joint account.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments. For information about the Master Portfolio’s policy regarding valuation of investments, refer to the Notes to Financial Statements.

The following table summarizes the Master Portfolio’s investments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Short-Term Securities(a)	$	—	$	54,240,631,538	$	—	$	54,240,631,538

^(a)  See above Schedule of Investments for values in each security type.

See notes to financial statements.

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 Treasury Money Market Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
U.S. Treasury Obligations — 47.8%
U.S. Treasury Bills(a):
1.87%, 01/02/20	$	50,610	$	50,610,000
1.56%, 01/07/20		138,290		138,254,736
1.77%, 01/09/20		243,780		243,686,194
2.03%, 01/23/20		117,305		117,163,083
1.77%, 01/30/20		276,755		276,368,175
1.89%, 02/20/20		107,580		107,304,968
1.58%, 02/25/20		211,710		211,208,598
1.89%, 02/27/20		475,885		474,498,588
1.56%, 03/12/20		14,260		14,216,970
1.91%, 03/26/20		99,500		99,063,029
1.56%, 04/02/20		85,055		84,723,498
1.66%, 04/16/20		41,690		41,491,139
1.98%, 04/23/20		395,265		392,875,002
1.65%, 04/30/20		125,000		124,329,167
1.57%, 05/07/20		105,210		104,640,273
1.59%, 05/14/20		113,050		112,397,764
1.61%, 05/28/20		225,000		223,546,453
1.60%, 06/25/20		230,000		228,244,180
1.79%, 09/10/20		25,295		24,985,684
U.S. Treasury Notes:
1.25% - 2.00%, 01/31/20(b)		834,190		834,169,855
1.25% - 1.38%, 02/29/20		138,445		138,272,787
1.38%, 03/31/20		16,790		16,762,654
1.13% - 2.38%, 04/30/20		150,435		150,395,931
(3 mo. Treasury money market yield + 0.03%), 1.56%, 04/30/20(c)		146,470		146,475,245
1.50% - 3.50%, 05/15/20		54,890		54,898,256
1.38% - 1.50%, 05/31/20		42,985		42,929,473
1.63%, 06/30/20		2,480		2,477,160

Security	Par (000)		Value
U.S. Treasury Obligations (continued)
(3 mo. Treasury money market yield + 0.04%), 1.57%, 07/31/20(c)	$	250,395	$	250,281,645
1.38% - 2.63%, 08/31/20		87,230		87,213,015
2.75%, 09/30/20		75,000		75,621,746
1.63%, 10/15/20		136,130		136,139,630
(3 mo. Treasury money market yield + 0.05%), 1.57%, 10/31/20(c)		50,000		49,956,639
2.63%, 11/15/20		360,055		363,163,616
1.63% - 2.00%, 11/30/20		100,990		101,266,525
2.38% - 2.50%, 12/31/20		25,220		25,419,714
(3 mo. Treasury money market yield + 0.12%), 1.64%, 01/31/21(c)		301,250		301,128,748
(3 mo. Treasury money market yield + 0.14%), 1.66%, 04/30/21(c)		183,440		183,427,687
(3 mo. Treasury money market yield + 0.22%), 1.75%, 07/31/21(c)		495,000		494,882,452
(3 mo. Treasury money market yield + 0.30%), 1.83%, 10/31/21(c)		33,945		33,981,966
Total U.S. Treasury Obligations — 47.8% (Cost — $6,558,472,245)				6,558,472,245
Total Repurchase Agreements — 52.7% (Cost — $7,214,989,999)				7,214,989,999
Total Investments — 100.5% (Cost — $13,773,462,244*)				13,773,462,244
Liabilities in Excess of Other Assets — (0.5)%				(74,212,970	)
Net Assets — 100.0%			$	13,699,249,274

* Cost for U.S. federal income tax purposes.

^(a)  Rates are discount rates or a range of discount rates as of period end.

^(b)  Variable or floating rate security, which interest rate adjusts periodically based on changes in current interest rates and prepayments on the underlying pool of assets. Rate shown is the rate in effect as of period end.

^(c)  Variable rate security. Rate shown is the rate in effect as of period end.

Repurchase Agreements

	Repurchase Agreements													Collateral
Counterparty	Coupon Rate			Purchase Date		Maturity Date		Par (000)		At Value (000)		Proceeds Including Interest		Position	Original Par		Position Received At Value
Bank of Nova Scotia		1.55	%		12/31/19		01/02/20	$	140,989	$	140,989	$	141,001,141	U.S. Treasury Obligation, 0.13% to 4.25%, due 4/15/20 to 2/15/49	$	128,653,900	$	143,821,204
Barclays Capital, Inc.		1.55			12/31/19		01/02/20		50,000		50,000		50,004,306	U.S. Treasury Obligation, 2.13%, due 5/31/26		49,912,600		51,000,089
BNP Paribas Securities Corp.		1.56			12/31/19		01/02/20		50,000		50,000		50,004,333	U.S. Treasury Obligation, 0.00% to 2.50%, due 2/27/20 to 8/15/48		45,148,237		51,000,000
Citigroup Global Markets, Inc.		1.55	(a)		12/31/19		01/02/20		262,000		262,000		262,022,561	U.S. Treasury Obligation, 0.63% to 3.63%, due 2/15/43 to 8/15/44		219,080,971		267,964,599
		1.55			12/31/19		01/02/20		265,000		265,000		265,022,819	U.S. Treasury Obligation, 3.00% to 3.38%, due 8/15/48 to 11/15/48		221,485,300		270,300,062
Total Citigroup Global Markets, Inc.										$	527,000						$	538,264,661
Credit Agricole Corp.(c)		1.55	(a)		12/31/19		01/02/20		411,000		411,000		411,035,392	U.S. Treasury Obligation, 1.25% to 2.25%, due 3/31/21 to 11/15/27		415,220,629		419,220,041
Fixed Income Clearing Corporation — SSB		3.50			12/03/19		01/02/20		50,000		50,000		50,145,833	U.S. Treasury Obligation, 3.50%, due 01/02/20		46,460,000		51,002,487

SCHEDULES OF INVESTMENTS 25

Schedule of Investments  (continued) December 31, 2019 Treasury Money Market Master Portfolio

Repurchase Agreements (continued)

	Repurchase Agreements													Collateral
Counterparty	Coupon Rate			Purchase Date		Maturity Date		Par (000)		At Value (000)		Proceeds Including Interest		Position	Original Par		Position Received At Value
HSBC Securities (USA), Inc.		1.55	%		12/31/19		01/02/20	$	169,000	$	169,000	$	169,014,553	U.S. Treasury Obligation, 0.00% to 2.75%, due 2/29/20 to 8/15/43	$	175,220,800	$	172,380,043
.		1.55	(b)		12/31/19		01/02/20		225,000		225,000		225,019,375	U.S. Treasury Obligation, 1.57% to 2.75%, due 7/31/20 to 2/15/45		226,970,700		229,500,013
Total HSBC Securities (USA), Inc.										$	394,000						$	401,880,056
J.P. Morgan Securities LLC		1.55			12/31/19		01/02/20		1,075,000		1,075,000		1,075,092,569	U.S. Treasury Obligation, 0.00% to 7.50%, due 4/30/20 to 11/15/49		1,059,584,100		1,096,500,093
		1.58			12/31/19		01/02/20		216,661		216,661		216,679,864	U.S. Treasury Obligation, 2.25%, due 8/15/27		212,750,000		220,994,063
		1.58			12/31/19		01/02/20		247,508		247,508		247,529,814	U.S. Treasury Obligation, 2.75%, due 2/15/28		234,300,000		252,458,250
		1.58			12/31/19		01/02/20		376,643		376,643		376,676,098	U.S. Treasury Obligation, 1.88%, due 3/31/22		379,902,000		384,175,898
		1.58			12/31/19		01/02/20		686,684		686,684		686,743,915	U.S. Treasury Obligation, 2.25%, due 11/15/27		677,550,000		700,417,313
		1.58			12/31/19		01/02/20		204,412		204,412		204,429,708	U.S. Treasury Obligation, 2.38%, due 5/15/27		200,000,000		208,500,000
		1.58			12/31/19		01/02/20		304,798		304,798		304,824,794	U.S. Treasury Obligation, 2.88%, due 5/15/28		287,200,000		310,894,000
		1.58			12/31/19		01/02/20		103,560		103,560		103,568,465	U.S. Treasury Obligation, 2.88%, due 5/31/25		99,417,000		105,630,563
		1.58			12/31/19		01/02/20		84,735		84,735		84,742,732	U.S. Treasury Obligation, 1.83%, due 10/31/21		86,000,000		86,430,000
		3.20			11/27/19		01/02/20		50,000		50,000		50,160,306	U.S. Treasury Obligation, 3.00%, due 11/15/44		45,183,000		51,000,311
		3.30			12/03/19		01/02/20		50,000		50,000		50,137,806	U.S. Treasury Obligation, 3.00%, due 11/15/44		45,183,000		51,000,311
		3.50			12/17/19		01/02/20		50,000		50,000		50,078,083	U.S. Treasury Obligation, 3.00%, due 11/15/44		45,183,000		51,000,311
Total J.P. Morgan Securities LLC										$	3,450,001						$	3,519,001,113
Merrill Lynch, Pierce, Fenner & Smith, Inc.		1.55			12/31/19		01/02/20		17,000		17,000		17,001,464	U.S. Treasury Obligation, 1.88% to 2.00%, due 5/31/22 to 10/31/22		17,170,200		17,340,071
Mufg Securities Americas Inc.		1.55			12/31/19		01/02/20		211,000		211,000		211,018,169	U.S. Treasury Obligation, 1.25% to 3.75%, due 8/31/20 to 8/15/41		211,169,100		215,220,039
Natixis SA		1.55	%		12/31/19		01/02/20		575,000		575,000		575,049,514	U.S. Treasury Obligation, 0.13% to 6.38%, due 7/15/20 to 2/15/49		538,674,100		586,500,079
		1.55	(b)		12/31/19		01/02/20		290,000		290,000		290,024,972	U.S. Treasury Obligation, 0.75% to 6.38%, due 5/15/21 to 2/15/46		228,046,100		295,800,007
Total Natixis SA										$	865,000						$	882,300,086
SG Americas Securities LLC		1.55			12/31/19		01/02/20		430,000		430,000		430,037,028	U.S. Treasury Obligation, 0.00%, due 5/15/23		557,044,812		438,600,000
TD Securities (USA) LLC		1.55			12/31/19		01/02/20		190,000		190,000		190,016,361	U.S. Treasury Obligation, 1.75% to 2.13%, due 11/30/24 to 12/31/26		191,644,800		193,800,058
Wells Fargo Securities LLC		1.55			12/31/19		01/02/20		429,000		429,000		429,036,942	U.S. Treasury Obligation, 0.13% to 2.88%, due 4/15/22 to 1/31/26		411,764,600		437,580,041
Total										$	7,214,990						$	7,360,029,946

^(a)  Traded in a joint account.

^(b)  Variable rate security. Rate as of period end and maturity is the date the principal owed can be recovered through demand.

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Treasury Money Market Master Portfolio

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments. For information about the Master Portfolio’s policy regarding valuation of investments, refer to the Notes to Financial Statements.

The following table summarizes the Master Portfolio’s investments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Short-Term Securities(a)	$	—	$	13,773,462,244	$	—	$	13,773,462,244

^(a)  See above Schedule of Investments for values in each security type.

See notes to financial statements.

SCHEDULES OF INVESTMENTS 27

Statements of Assets and Liabilities

December 31, 2019

	Money Market Master Portfolio		Treasury Money Market Master Portfolio
ASSETS
Investments at value — unaffiliated(a)	$	38,463,130,787	$	6,558,472,245
Repurchase agreements at value(b)		15,777,500,751		7,214,989,999
Cash		101,546,825		44,769
Receivables:
Investments sold — unaffiliated		—		5,887,297
Interest — unaffiliated		105,245,492		11,724,302
Total assets		54,447,423,855		13,791,118,612
LIABILITIES
Payables:
Investments purchased		—		90,614,058
Investment advisory fees		3,534,719		1,176,477
Trustees’ fees		103,017		48,208
Other accrued expenses		100,402		30,595
Total liabilities		3,738,138		91,869,338
NET ASSETS	$	54,443,685,717	$	13,699,249,274
NET ASSETS CONSIST OF
Investors’ capital	$	54,430,102,135	$	13,699,249,274
Net unrealized appreciation (depreciation)		13,583,582		—
NET ASSETS	$	54,443,685,717	$	13,699,249,274
(a) Investments at cost — unaffiliated	$	38,449,547,205	$	6,558,472,245
(b) Repurchase agreements at cost — unaffiliated	$	15,777,500,751	$	7,214,989,999

See notes to financial statements.

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Operations

Year Ended December 31, 2019

	Money Market Master Portfolio			Treasury Money Market Master Portfolio
INVESTMENT INCOME
Interest — unaffiliated	$	1,254,372,445		$	237,062,858
EXPENSES
Investment advisory		51,229,211			10,816,874
Independent Trustees		420,426			150,003
Professional		140,711			40,504
Total expenses		51,790,348			11,007,381
Less fees waived and/or reimbursed by the Manager		(15,929,900	)		(3,435,569	)
Total expenses after fees waived and/or reimbursed		35,860,448			7,571,812
Net investment income		1,218,511,997			229,491,046
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain from investments		658,671			1,208,116
Net change in unrealized appreciation (depreciation) on investments		14,197,832			—
Net realized and unrealized gain		14,856,503			1,208,116
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	1,233,368,500		$	230,699,162

See notes to financial statements.

FINANCIAL STATEMENTS 29

Statements of Changes in Net Assets

	Money Market Master Portfolio						Treasury Money Market Master Portfolio
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	1,218,511,997		$	1,060,900,668		$	229,491,046		$	152,172,022
Net realized gain		658,671			2,218,840			1,208,116			181,799
Net change in unrealized appreciation (depreciation)		14,197,832			(1,677,441	)		—			—
Net increase in net assets resulting from operations		1,233,368,500			1,061,442,067			230,699,162			152,353,821
CAPITAL TRANSACTIONS
Proceeds from contributions		235,125,900,281			203,087,934,988			215,732,811,573			130,455,316,898
Value of withdrawals		(229,255,796,451	)		(212,943,735,070	)		(210,316,698,539	)		(131,903,567,464	)
Net increase (decrease) in net assets derived from capital transactions		5,870,103,830			(9,855,800,082	)		5,416,113,034			(1,448,250,566	)
NET ASSETS
Total increase (decrease) in net assets		7,103,472,330			(8,794,358,015	)		5,646,812,196			(1,295,896,745	)
Beginning of year		47,340,213,387			56,134,571,402			8,052,437,078			9,348,333,823
End of year	$	54,443,685,717		$	47,340,213,387		$	13,699,249,274		$	8,052,437,078

See notes to financial statements.

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights

	Money Market Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		2.45	%		2.10	%		1.23	%		0.63	%		0.21	%
Ratios to Average Net Assets
Total expenses		0.10	%		0.10	%		0.10	%		0.10	%		0.10	%
Total expenses after fees waived and/or reimbursed		0.07	%		0.07	%		0.07	%		0.07	%		0.07	%
Net investment income		2.38	%		2.06	%		1.25	%		0.60	%		0.21	%
Supplemental Data
Net assets, end of year (000)	$	54,443,686		$	47,340,213		$	56,134,571		$	41,223,924		$	43,289,154

See notes to financial statements.

FINANCIAL HIGHLIGHTS 31

Financial Highlights  (continued)

	Treasury Money Market Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		2.17	%		1.81	%		0.84	%		0.32	%		0.03	%
Ratios to Average Net Assets
Total expenses		0.10	%		0.10	%		0.10	%		0.10	%		0.10	%
Total expenses after fees waived and/or reimbursed		0.07	%		0.07	%		0.07	%		0.07	%		0.07	%
Net investment income		2.12	%		1.76	%		0.87	%		0.31	%		0.04	%
Supplemental Data
Net assets, end of year (000)	$	13,699,249		$	8,052,437		$	9,348,334		$	6,067,065		$	3,450,181

See notes to financial statements.

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. The financial statements and these accompanying notes relate to two series of MIP. Money Market Master Portfolio and Treasury Money Market Master Portfolio (each, a “ Master Portfolio” and together, the “Master Portfolios”). Each Master Portfolio is classified as diversified.

Treasury Money Market Master Portfolio operates as a “government money market fund” under Rule2a-7 under the 1940 Act. The Master Portfolio is not subject to liquidity fees or temporary suspensions of redemptions due to declines in the Master Portfolio’s weekly liquid assets.

BlackRock Cash Funds: Institutional, the sole feeder fund into Money Market Master Portfolio, prices and transacts its shares at a NAV per share calculated to four decimal places, reflecting market-based values of its portfolio holdings (i.e., at a “floating” NAV).

With respect to Money Market Master Portfolio, the Board of Trustees of MIP (the “Board”) is permitted to impose a liquidity fee of up to 2% of the value of shares redeemed or temporarily restrict redemptions from Money Market Master Portfolio for up to 10 business days during a 90 day period, in the event that such Money Market Master Portfolio’s weekly liquid assets fall below certain thresholds.

The Master Portfolios, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, are included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. Each Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Interest income, including amortization and accretion of premiums and discounts on debt securities, is recognized on an accrual basis.

Liquidity Fees:Any liquidity fees imposed on the value of shares redeemed in the event that the Money Market Master Portfolio’s weekly liquid assets fall below certain thresholds are recorded aspaid-in-capital. The liquidity fees are collected and retained by the Money Market Master Portfolio for the benefit of the Money Market Master Portfolio’s remaining shareholders.

Indemnifications:In the normal course of business, a Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. A Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against a Master Portfolio, which cannot be predicted with any certainty.

Other:Expenses directly related to a Master Portfolio are charged to that Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies (Money Market Master Portfolio): The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the New York Stock Exchange (“NYSE”) (generally 3:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board. The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Investment Valuation Policies(Treasury Money Market Master Portfolio): U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio’s investments are valued under the amortized cost method which approximates current market value in accordance with Rule2a-7 under the 1940 Act. Under this method, investments are valued at cost when purchased and, thereafter, a constant proportionate accretion of discounts and amortization of premiums are recorded until the maturity of the security. The Master Portfolio seeks to maintain the NAV per share of its feeder funds at $1.00, although there is no assurance that it will be able to do so on a continuing basis.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of the Money Market Master Portfolio’s assets and liabilities:

• Fixed-income securities for which market quotations are readily available are generally valued using the last available bid prices or current market quotations provided by independent dealers or third party pricing services. Floating rate loan interests are valued at the mean of the bid prices from one or more independent brokers or dealers as obtained from a third party pricing service. Pricing services generally value fixed-income securities assuming orderly transactions of an institutional round lot size, but a fund may hold or transact in such securities in smaller, odd lot sizes. Odd lots may trade at lower prices than institutional round lots. The pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values, including transaction data (e.g., recent representative bids and offers), credit quality information, perceived market movements, news, and other relevant information. Certain fixed-income

NOTESTO FINANCIAL STATEMENTS 33

Notes to Financial Statements  (continued)

securities, including asset-backed and mortgage related securities may be valued based on valuation models that consider the estimated cash flows of each tranche of the entity, establish a benchmark yield and develop an estimated tranche specific spread to the benchmark yield based on the unique attributes of the tranche. The amortized cost method of valuation may be used with respect to debt obligations with sixty days or less remaining to maturity unless the Manager determines such method does not represent fair value.

• Investments are valued on the basis of prices provided by dealers or pricing services. In determining the value of a particular investment, pricing services may use certain information with respect to transactions in such investments, quotations from dealers, pricing matrixes, market transactions in comparable investments and information with respect to various relationships between investments.

• Municipal investments (including commitments to purchase such investments on a “when-issued” basis) are valued on the basis of prices provided by dealers or pricing services. In determining the value of a particular investment, pricing services may use certain information with respect to transactions in such investments, quotations from dealers, pricing matrixes, market transactions in comparable investments and information with respect to various relationships between investments.

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that each Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. The categorization of a value determined for investments is based on the pricing transparency of the investments and is not necessarily an indication of the risks associated with investing in those securities.

4. SECURITIES AND OTHER INVESTMENTS

Repurchase Agreements: Repurchase agreements are commitments to purchase a security from a counterparty who agrees to repurchase the same security at a mutually agreed upon date and price. On a daily basis, the counterparty is required to maintain eligible collateral subject to the agreement and in value no less than the agreed upon repurchase amount. Repurchase agreements may be traded bilaterally, in atri-party arrangement or may be centrally cleared through a sponsoring agent. Subject to the custodial undertaking associated with atri-party repurchase arrangement and for centrally cleared repurchase agreements, a third party custodian maintains accounts to hold collateral for a fund and its counterparties. Typically, a fund and counterparty are not permitted to sell,re-pledge or use the collateral absent a default by the counterparty or a fund, respectively. A fund, along with other registered investment companies advised by the Manager, may transfer uninvested cash into a single joint trading account which is then invested in one or more repurchase agreements.

In the event the counterparty defaults and the fair value of the collateral declines, a fund could experience losses, delays and costs in liquidating the collateral.

Repurchase agreements are entered into by a fund under Master Repurchase Agreements (each, an “MRA”). The MRA permits a fund, under certain circumstances including an event of default (such as bankruptcy or insolvency), to offset payables and/or receivables with collateral held by and/or posted to the counterparty. As a result, one single net payment is created. Bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of the MRA counterparty’s bankruptcy or insolvency. Based on the terms of the MRA, a fund receives securities as collateral with a market value in excess of the repurchase price at maturity. Upon a bankruptcy or insolvency of the MRA counterparty, a fund would recognize a liability with respect to such excess collateral. The liability reflects a fund’s obligation under bankruptcy law to return the excess to the counterparty.

5. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory:MIP, on behalf of the Master Portfolios, entered into an Investment Advisory Agreement with the Manager, the Master Portfolios’ investment adviser and an indirect, wholly-owned subsidiary of BlackRock, Inc. (“BlackRock”), to provide investment advisory services. The Manager is responsible for the management of each Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of each Master Portfolio.

For such services, each Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.10% of the average daily value of each Master Portfolio’s net assets.

Administration: MIP, on behalf of the Master Portfolios, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the Master Portfolios’ ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Master Portfolios.

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

BAL is not entitled to compensation for providing administration services to the Master Portfolios, for so long as BAL is entitled to compensation for providing administration services to corresponding feeder funds that invest substantially all of their assets in the Master Portfolios, or BAL (or an affiliate) receives investment advisory fees from the Master Portfolios.

Expense Waivers and Reimbursements: The Manager contractually agreed to waive a portion of its investment advisory fees equal to the annual rate of 0.03% of the average daily value of each Master Portfolio’s net assets through April 30, 2020. These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. For the year ended December 31, 2019, the amounts waived were as follows:

Money Market Master Portfolio	$	15,368,763
Treasury Money Market Master Portfolio		3,245,062

The Manager has also voluntarily agreed to waive a portion of their respective investment advisory fees to enable the feeders that invest in the Master Portfolios to maintain minimum levels of daily net investment income if applicable. The Manager may discontinue the voluntary waiver at any time. For the year ended December 31, 2019, there were no fees waived and/or reimbursed by the Manager under this agreement.

The fees and expenses of MIP’s Trustees who are not “interested persons” of MIP, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Master Portfolios’ independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Master Portfolios. BAL has contractually agreed to reimburse the Master Portfolios or provide an offsetting credit against the administration fees paid by the Master Portfolios in an amount equal to these independent expenses through April 30, 2020. These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. For the year ended December 31, 2019, the amounts waived were as follows:

Money Market Master Portfolio	$	561,137
Treasury Money Market Master Portfolio		190,507

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), each Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by each Master Portfolio’s investment policies and restrictions. Each Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolios did not participate in the Interfund Lending Program.

Trustees and Officers:Certain Trustees and/or officers of MIP are directors and/or officers of BlackRock or its affiliates.

Other Transactions:The Master Portfolios may purchase securities from, or sell securities to, an affiliated fund provided the affiliation is due solely to having a common investment adviser, common officers, or common trustees. For the year ended December 31, 2019, the purchase and sale transactions and any net realized gains (losses) with an affiliated fund in compliance with Rule17a-7 under the 1940 Act were as follows:

	Purchases		Sales		Realized Gain (Loss)
Money Market Master Portfolio	$	—	$	120,731,729	$	—

6. INCOME TAX INFORMATION

Treasury Money Market Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended. Treasury Money Market Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Treasury Money Market Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

Money Market Master Portfolio is disregarded as an entity separate from its owner for tax purposes. As such, the owner of the Master Portfolio is treated as the owner of the net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so the owner of the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

NOTESTO FINANCIAL STATEMENTS 35

Notes to Financial Statements  (continued)

7. PRINCIPAL RISKS

Many municipalities insure repayment of their bonds, which may reduce the potential for loss due to credit risk. The market value of these bonds may fluctuate for other reasons, including market perception of the value of such insurance, and there is no guarantee that the insurer will meet its obligation.

Inventories of municipal bonds held by brokers and dealers may decrease, which would lessen their ability to make a market in these securities. Such a reduction in market making capacity could potentially decrease a Master Portfolio’s ability to buy or sell bonds. As a result, a Master Portfolio may sell a security at a lower price, sell other securities to raise cash, or give up an investment opportunity, any of which could have a negative impact on performance. If a Master Portfolio needed to sell large blocks of bonds, those sales could further reduce the bonds’ prices and impact performance.

In the normal course of business, certain Master Portfolios invest in securities or other instruments and may enter into certain transactions, and such activities subject each Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. Each Master Portfolio’s prospectus provides details of the risks to which each Master Portfolio is subject.

Certain obligations held by the Money Market Master Portfolio have a credit enhancement or liquidity feature that may, under certain circumstances, provide for repayment of principal and interest on the obligation when due. These enhancements, which may include letters of credit,stand-by bond purchase agreements and/or third party insurance, are issued by financial institutions. The value of the obligations may be affected by changes in creditworthiness of the entities that provide the credit enhancements or liquidity features. The Money Market Master Portfolio monitors its exposure by reviewing the creditworthiness of the issuers, as well as the financial institutions issuing the credit enhancements and by limiting the amount of holdings with credit enhancements from one financial institution.

Certain affiliates indirectly invest in the Master Portfolios through the SL Agency Shares of BlackRock Cash Funds. As of period end, these affiliated investors represent a significant portion of the net assets of Money Market Master Portfolio and Treasury Money Market Master Portfolio.

Counterparty Credit Risk:The Master Portfolios may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolios manage counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Master Portfolios to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolios’ exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statements of Assets and Liabilities, less any collateral held by the Master Portfolios.

8. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolios through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of

Master Investment Portfolio and Investors of Money Market Master Portfolio and Treasury Money Market Master Portfolio

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities, including the schedules of investments, of Money Market Master Portfolio and Treasury Money Market Master Portfolio (two of the series constituting Master Investment Portfolio, hereafter collectively referred to as the “Master Portfolios”) as of December 31, 2019, the related statements of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Master Portfolios as of December 31, 2019, the results of each of their operations for the year then ended, the changes in each of their net assets for each of the two years in the period ended December 31, 2019 and each of the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinions

These financial statements are the responsibility of the Master Portfolios’ management. Our responsibility is to express an opinion on the Master Portfolios’ financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolios in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinions.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 14, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

REPORTOF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM 37

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019 and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

TRUSTEEAND OFFICER INFORMATION 39

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment  Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015); President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate. (c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015. (d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex. (e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge by calling(800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Administrator

BlackRock Advisors LLC

Wilmington, DE 19809

Custodian and Accounting Agent

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

State Street Bank and Trust Company

North Quincy, MA 02171

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Distributor

BlackRock Investments, LLC

New York, NY 10022

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

TRUSTEEAND OFFICER INFORMATION 41

Additional Information

General Information

Householding

The Funds will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Transfer Agent at (888) 204-3956.

Availability of Quarterly Schedule of Investments

The Funds/Master Portfolios file their complete schedule of portfolio holdings with the SEC each month on Forms N-MFP. The Funds’/Master Portfolios’ reports on Forms N-MFP are available on the SEC’s website at sec.gov. Each Fund/Master Portfolio makes portfolio holdings available to shareholders/interest holders on its website at blackrock.com.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Funds/Master Portfolios use to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling (800) 626-1960; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Funds/Master Portfolios voted proxies relating to securities held in the Funds’/Master Portfolios’ portfolios during the most recent12-month period ended June 30 is available upon request and without charge (1) atblackrock.com, or by calling (800) 626-1960; and (2) on the SEC’s website at sec.gov.

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding theirnon-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personalnon-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose tonon-affiliated third parties anynon-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. Thesenon-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access tonon-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect thenon-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Glossary of Terms Used in this Report

Portfolio Abbreviations
AGM	Assured Guaranty Municipal Corp.
LIBOR	London Inter-bank Offered Rate
RB	Revenue Bonds
SOFR	Secured Overnight Financing Rate
VRDN	Variable Rate Demand Notes

Important Fund Information

The following applies to BlackRock Cash Funds: Institutional and its corresponding Master Portfolio: This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund’s current prospectus. You could lose money by investing in the Fund. Because the share price of the Fund will fluctuate, when you sell your shares they may be worth more or less than what you originally paid for them. The Fund may impose a fee upon sale of your shares or may temporarily suspend your ability to sell shares if the Fund’s liquidity falls below required minimums because of market conditions or other factors. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund’s sponsor has no legal obligation to provide financial support to the Fund at any time. Performance data quoted represents past performance and does not guarantee future results. Total return information assumes reinvestment of all distributions. Current performance may be higher or lower than the performance data quoted. For current month-end performance information, call(800) 626-1960. The Fund’s current 7-day yield more closely reflects the current earnings of the Fund than the total returns quoted. Statements and other information herein are as dated and are subject to change.

The following applies to BlackRock Cash Funds: Treasury and its corresponding Master Portfolio: This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund’s current prospectus. You could lose money by investing in the Fund. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the Fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund’s sponsor has no legal obligation to provide financial support to the Fund at any time. Performance data quoted represents past performance and does not guarantee future results. Total return information assumes reinvestment of all distributions. Current performance may be higher or lower than the performance data quoted. For current month-end performance information, call(800) 626-1960. The Fund’s current7-day yield more closely reflects the current earnings of the Fund than the total returns quoted. Statements and other information herein are as dated and are subject to change.

GLOSSARYOF TERMS USEDINTHIS REPORT / IMPORTANT FUND INFORMATION 43

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

MMF3-12/19-AR

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· BlackRock LifePath^® Dynamic Retirement Fund

· BlackRock LifePath^® Dynamic 2030 Fund

· BlackRock LifePath^® Dynamic 2040 Fund

· BlackRock LifePath^® Dynamic 2050 Fund

· BlackRock LifePath^® Dynamic 2060 Fund

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of each Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call(800) 441-7762 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: (i) accessing the BlackRock website at www.blackrock.com/edelivery and logging into your accounts, if you hold accounts directly with BlackRock, or (ii) contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summaries		4
About Fund Performance		16
Disclosure of Expenses		17
Derivative Financial Instruments		18
Fund Financial Statements:
Statements of Assets and Liabilities		19
Statements of Operations		20
Statements of Changes in Net Assets		21
Fund Financial Highlights		24
Fund Notes to Financial Statements		49
Fund Report of Independent Registered Public Accounting Firm		57
Important Tax Information		57
Master Portfolio Information		58
Master Portfolio Financial Statements:
Schedules of Investments		60
Statements of Assets and Liabilities		75
Statements of Operations		76
Statements of Changes in Net Assets		77
Master Portfolio Financial Highlights		80
Master Portfolio Notes to Financial Statements		85
Master Portfolio Report of Independent Registered Public Accounting Firm		94
Statement Regarding Liquidity Risk Management Program		95
Trustee and Officer Information		96
Additional Information		100
Glossary of Terms Used in this Report		101

3

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic Funds

Portfolio Management Commentary

How did each Fund perform?

The BlackRock LifePath^® Dynamic Funds with target dates of 2030, 2040, 2050 and 2060 and the BlackRock LifePath^® Dynamic Retirement Fund (together, the “LifePath Dynamic Funds”) invest in their respective LifePath^® Dynamic Master Portfolio.

For the12-month period ended December 31, 2019, the BlackRock LifePath^® Dynamic Retirement Fund and the LifePath Dynamic Funds with target dates of 2030 and 2040 outperformed their respective custom benchmarks, with the exception of the Investor C Shares, which underperformed their respective custom benchmarks. For the same period, the LifePath Dynamic Funds with target dates of 2050 and 2060 each underperformed their respective custom benchmarks. The returns for the LifePath Dynamic Funds include fund expenses. The custom benchmarks have no expenses associated with performance.

What factors influenced performance?

BlackRock Advantage Emerging Markets Fund (an equity strategy) and BlackRock Tactical Opportunities Fund (a global tactical asset allocation strategy) detracted from the LifePath Dynamic Funds’ returns as they lagged their respective benchmarks. In terms of macro themes, active currency positioning weighed on returns over the period, and an underweight to U.S.10- and30-year bond futures also modestly detracted.

At an investment strategy level, underlying actively managed strategies were generally the largest positive contributors to active returns, while macro themes also contributed in the nearer-dated vintages. Specifically, CoreAlpha Bond Master Portfolio (a domestic fixed-income strategy), Active Stock Master Portfolio (a diversified equity strategy) and active real estate strategies contributed to returns. With regard to the LifePath Dynamic Funds’ macro themes, an overweight to U.S. equities was the largest contributor to returns for the period.

As part of their investment strategy, the LifePath Dynamic Funds may use derivatives to achieve exposure to a market or to manage risk. At times during the period, the LifePath Dynamic Funds had elevated cash positions that were primarily due to collateral posted against these derivatives. The LifePath Dynamic Funds’ cash balances had no material impact on their respective performance.

Describe recent portfolio activity.

Each LifePath Dynamic Fund has its own time horizon, which affects its acceptable level of risk and, in turn, the strategic allocation of its holdings across asset classes. On a quarterly basis, the strategic allocation of each LifePath Dynamic Fund is systematically adjusted to reflect the shareholders’ remaining investment time horizon.

The LifePath Dynamic Funds entered the period with tactical overweights to U.S. and Japanese equities as expressions of the investment adviser’s macro theme of Global Reflation. As markets rebounded strongly from December 2018 lows, the investment adviser reduced holdings in some of the domestic exposure and all the Japanese exposure. Concurrently, the investment adviser introduced an overweight tofar-dated U.S. bonds (via30-year bond futures) as part of a new theme called U.S. Macro Moderation. This exposure was maintained through the first three quarters of 2019, based on the investment adviser’s belief that the U.S. economy was in a state of relative moderation with limited risk of overheating or falling into deep recession.

As pricing moved in line with expectations, the LifePath Dynamic Funds’ overweight tofar-dated U.S. bonds was removed early in the fourth quarter of 2019. The LifePath Dynamic Funds maintained an overweight to U.S. equities throughout the period and introduced underweights to U.S.10-year and U.S.30-year bond futures in April and May 2019, respectively, as expressions of Global Reflation. This fixed-income positioning reflected the investment adviser’s view that despite the notable slowing in global activity data and dovish shift in global central bank tones, price levels for U.S. bonds had risen to levels inconsistent with fundamentals. These three positions were maintained for the rest of the period, although they were trimmed in the fourth quarter. The LifePath Dynamic Funds entered the period with an overweight to the euro, which was increased near the middle of the period, before being modestly trimmed in the latter half of the period as pricing moved in line with expectations. September’s European Central Bank (“ECB”) policy meeting gave the investment adviser increased conviction that the ECB was reaching the limits of both its willingness and its ability to proactively ease policy. Even as challenges to financial stability linger, the investment adviser expects trends in growth, inflation and policy between the Eurozone and the United States to converge over the coming months, and as such expect this to be supportive of a euro overweight position. The LifePath Dynamic Funds closed an overweight to the Australian dollar toward the middle of the period. With an escalation in global trade tensions weighing on the export-oriented economy, expectations of a rate cut from the Reserve Bank of Australia increased, leaving the theme with limited upside potential.

Describe portfolio positioning at period end.

At period end, each of the LifePath Dynamic Funds was invested according to its respective strategic allocation benchmark within tolerance limits.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic Funds

Glide Path Evolution

Under normal circumstances, the asset allocation of each LifePath Dynamic Fund will change over time according to a “glide path” as each LifePath Dynamic Fund approaches its respective target date. The glide path represents the shifting of asset classes over time. Each LifePath Dynamic Fund’s asset mix becomes more conservative — prior to retirement — as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of each LifePath Dynamic Fund, which may be a primary source of income after retirement. As each LifePath Dynamic Fund approaches its target date, its asset allocation will shift so that it invests a greater percentage of its assets in fixed-income funds. The asset allocation targets are established by the portfolio managers. The investment team, including the portfolio managers, meets regularly to assess market conditions, review the asset allocation targets of each LifePath Dynamic Fund, and determine whether any changes are required to enable each LifePath Dynamic Fund to achieve its investment objective. Because the BlackRock LifePath^® Dynamic Retirement Fund is in its most conservative phase, its allocation generally does not become more conservative over time, although its allocation may change to maintain its risk profile.

Although the asset allocation targets listed for the glide path are general, long-term targets, BlackRock Fund Advisors (“BFA” or the “Manager”) may adjust the allocation to equity and fixed-income in each LifePath Dynamic Fund, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of each LifePath Dynamic Fund. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect the LifePath Dynamic Fund or achieve its investment objective.

FUND SUMMARY 5

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic Retirement Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic Retirement Fund (“LifePath Dynamic Retirement Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic Retirement Fund will be broadly diversified across global asset classes.

At a meeting held on May 15, 2019, the Board of Trustees of BlackRock Funds III, on behalf of the LifePath Dynamic Fund, approved a reorganization (the “Reorganization”) of BlackRock LifePath^® Dynamic 2020 Fund (the “Target Fund”), with and into the LifePath Dynamic Fund. Shareholders of the Target Fund or LifePath Dynamic Fund were not required to approve the Reorganization. The Reorganization closed on November 18, 2019.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(b)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic Retirement Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
01/01/09 to 12/31/09		52.9	%		9.1	%		N/A			1.6	%		10.8	%		N/A			N/A			4.7	%		18.7	%		2.2	%
01/01/10 to 12/31/10		52.9			9.1			N/A			1.1			10.8			N/A			N/A			5.0			18.9			2.2
01/01/11 to 12/31/11		52.9			9.1			N/A			0.8			11.3			8.6	%		1.7	%		2.8			11.6			1.2
01/01/12 to 12/31/12		52.9			9.1			1.0	%		0.3			11.3			21.2			4.2			N/A			N/A			N/A
01/01/13 to 12/31/13		52.9			9.1			3.7			0.1			10.1			19.7			4.4			N/A			N/A			N/A
01/01/14 to 12/31/14		52.6			9.0			3.8			0.2			10.2			19.9			4.3			N/A			N/A			N/A
01/01/15 to 12/31/15		51.1			8.8			3.8			0.5			11.0			21.0			3.8			N/A			N/A			N/A
01/01/16 to 12/31/16		51.1			8.8			3.7			0.5			11.3			20.9			3.7			N/A			N/A			N/A
01/01/17 to 12/31/17		51.2			8.8			3.7			0.5			11.3			20.3			4.2			N/A			N/A			N/A
01/01/18 to 12/31/18		51.2			8.8			N/A			0.5			13.7			21.8			4.0			N/A			N/A			N/A
01/01/19 to 12/31/19		52.0			8.0			N/A			2.3			12.3			22.1			3.3			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 16 for descriptions of the indexes.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic Retirement Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
				1 Year						5 Years						10 Years
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		4.73	%		16.91	%		N/A			5.57	%		N/A			6.07	%		N/A
Investor A		4.59			16.56			10.44	%		5.30			4.17	%		5.81			5.24	%
Investor C		4.16			15.54			14.54			4.47			4.47			4.94			4.94
Class K		4.84			17.07			N/A			5.80			N/A			6.38			N/A
Class R		4.39			16.24			N/A			5.06			N/A			5.51			N/A
LifePath Dynamic Retirement Fund Custom Benchmark		5.08			16.06			N/A			5.29			N/A			6.20			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.75			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.36			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			8.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			5.21			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			13.54			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			11.83			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 16 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes. LifePath Dynamic Retirement Fund’s returns prior to March 31, 2018 are the returns of LifePath Dynamic Retirement Fund when its assets could be allocated to underlying funds that invest primarily in commodities. LifePath Dynamic Retirement Fund’s returns between December 14, 2015 and November 7, 2016 are the returns of LifePath Dynamic Retirement Fund when it incorporated different allocations in its glidepath and had a different investment strategy. LifePath Dynamic Retirement Fund’s returns prior to December 14, 2015 are the returns of LifePath Dynamic Retirement Fund under a different investment strategy. LifePath Dynamic Retirement Fund’s returns prior to November 28, 2014 are the returns of LifePath Dynamic Retirement Fund when it had a different target asset allocation.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 7

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2030 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2030 Fund (“LifePath Dynamic 2030 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2030 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(b)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2030 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
01/01/09 to 12/31/09		21.0	%		3.1	%		N/A			7.0	%		21.0	%		N/A			N/A			6.6	%		38.2	%		3.1	%
01/01/10 to 12/31/10		22.0			3.2			N/A			6.3			20.7			N/A			N/A			6.4			38.6			2.8
01/01/11 to 12/31/11		23.5			3.4			N/A			6.0			20.9			17.0	%		1.3	%		3.7			22.6			1.6
01/01/12 to 12/31/12		25.8			3.8			1.0	%		6.0			20.2			40.2			3.0			N/A			N/A			N/A
01/01/13 to 12/31/13		27.6			4.0			3.9			5.7			19.3			36.6			2.9			N/A			N/A			N/A
01/01/14 to 12/31/14		27.5			4.0			3.9			6.1			19.8			35.8			2.9			N/A			N/A			N/A
01/01/15 to 12/31/15		21.8			3.4			3.9			7.7			22.2			38.5			2.5			N/A			N/A			N/A
01/01/16 to 12/31/16		24.5			3.6			3.9			7.6			21.9			36.0			2.5			N/A			N/A			N/A
01/01/17 to 12/31/17		25.9			4.0			3.9			7.4			21.4			35.0			2.4			N/A			N/A			N/A
01/01/18 to 12/31/18		27.1			4.2			N/A			7.5			22.5			36.2			2.5			N/A			N/A			N/A
01/01/19 to 12/31/19		27.0			6.0			N/A			3.1			25.2			36.0			2.7			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 16 for descriptions of the indexes.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2030 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
				1 Year						5 Years						10 Years
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		6.71	%		22.07	%		N/A			7.36	%		N/A			7.93	%		N/A
Investor A		6.57			21.72			15.33	%		7.10			5.95	%		7.66			7.08	%
Investor C		6.11			20.76			19.76			6.23			6.23			6.75			6.75
Class K		6.77			22.27			N/A			7.61			N/A			8.26			N/A
Class R		6.39			21.44			N/A			6.86			N/A			7.32			N/A
LifePath Dynamic 2030 Fund Custom Benchmark		6.94			21.16			N/A			6.96			N/A			8.14			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.75			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.36			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			8.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			5.21			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			13.54			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			11.83			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 16 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes. LifePath Dynamic 2030 Fund’s returns prior to March 31, 2018 are the returns of LifePath Dynamic 2030 Fund when its assets could be allocated to underlying funds that invest primarily in commodities. LifePath Dynamic 2030 Fund’s returns between December 14, 2015 and November 7, 2016 are the returns of LifePath Dynamic 2030 Fund when it incorporated different allocations in its glidepath and had a different investment strategy. LifePath Dynamic 2030 Fund’s returns prior to December 14, 2015 are the returns of LifePath Dynamic 2030 Fund under a different investment strategy. LifePath Dynamic 2030 Fund’s returns prior to November 28, 2014 are the returns of LifePath Dynamic 2030 Fund when it had a different glidepath and target asset allocation.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 9

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2040 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2040 Fund (“LifePath Dynamic 2040 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2040 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(b)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2040 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
01/01/09 to 12/31/09		10.4	%		1.1	%		N/A			8.8	%		24.5	%		N/A			N/A			7.2	%		44.6	%		3.4	%
01/01/10 to 12/31/10		11.2			1.1			N/A			8.1			24.2			N/A			N/A			6.9			45.5			3.0
01/01/11 to 12/31/11		12.7			1.3			N/A			7.9			24.5			20.1	%		1.2	%		4.0			26.6			1.7
01/01/12 to 12/31/12		15.3			1.6			1.0	%		8.2			23.7			47.7			2.5			N/A			N/A			N/A
01/01/13 to 12/31/13		17.3			1.7			3.9			8.1			23.1			43.6			2.3			N/A			N/A			N/A
01/01/14 to 12/31/14		16.1			1.6			3.9			9.0			24.2			42.9			2.3			N/A			N/A			N/A
01/01/15 to 12/31/15		5.7			0.7			4.1			12.1			28.1			47.3			2.0			N/A			N/A			N/A
01/01/16 to 12/31/16		8.4			0.9			4.1			12.1			28.0			44.0			2.5			N/A			N/A			N/A
01/01/17 to 12/31/17		9.2			1.2			4.1			12.3			27.6			44.5			1.2			N/A			N/A			N/A
01/01/18 to 12/31/18		10.3			1.4			N/A			12.8			28.2			46.0			1.3			N/A			N/A			N/A
01/01/19 to 12/31/19		8.4			3.0			N/A			4.2			35.2			47.0			2.2			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 16 for descriptions of the indexes.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2040 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
				1 Year						5 Years						10 Years
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		8.10	%		25.72	%		N/A			8.30	%		N/A			8.78	%		N/A
Investor A		7.86			25.29			18.71	%		8.01			6.86	%		8.50			7.91	%
Investor C		7.50			24.35			23.35			7.17			7.17			7.57			7.57
Class K		8.17			25.96			N/A			8.54			N/A			9.11			N/A
Class R		7.82			25.10			N/A			7.79			N/A			8.14			N/A
LifePath Dynamic 2040 Fund Custom Benchmark		8.43			25.01			N/A			8.01			N/A			9.09			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.75			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.36			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			8.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			5.21			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			13.54			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			11.83			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 16 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes. LifePath Dynamic 2040 Fund’s returns prior to March 31, 2018 are the returns of LifePath Dynamic 2040 Fund when its assets could be allocated to underlying funds that invest primarily in commodities. LifePath Dynamic 2040 Fund’s returns between December 14, 2015 and November 7, 2016 are the returns of LifePath Dynamic 2040 Fund when it incorporated different allocations in its glidepath and had a different investment strategy. LifePath Dynamic 2040 Fund’s returns prior to December 14, 2015 are the returns of LifePath Dynamic 2040 Fund under a different investment strategy. LifePath Dynamic 2040 Fund’s returns prior to November 28, 2014 are the returns of LifePath Dynamic 2040 Fund when it had a different glidepath and target asset allocation.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 11

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2050 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2050 Fund (“LifePath Dynamic 2050 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2050 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(b)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2050 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
01/01/09 to 12/31/09		1.0	%		N/A			N/A			9.1	%		28.3	%		N/A			N/A			9.5	%		47.5	%		4.6	%
01/01/10 to 12/31/10		1.1			N/A			N/A			9.8			27.4			N/A			N/A			7.6			50.7			3.4
01/01/11 to 12/31/11		2.7			N/A			N/A			9.7			27.6			22.8	%		1.1	%		4.4			29.9			1.8
01/01/12 to 12/31/12		5.9			N/A			1.0	%		10.2			26.8			54.0			2.1			N/A			N/A			N/A
01/01/13 to 12/31/13		8.2			N/A			4.0			10.1			26.3			49.6			1.8			N/A			N/A			N/A
01/01/14 to 12/31/14		8.2			N/A			3.9			11.0			27.3			47.8			1.8			N/A			N/A			N/A
01/01/15 to 12/31/15		1.0			N/A			4.2			13.7			29.9			49.2			2.0			N/A			N/A			N/A
01/01/16 to 12/31/16		1.0			N/A			4.4			14.1			30.3			48.4			1.8			N/A			N/A			N/A
01/01/17 to 12/31/17		1.0			N/A			4.3			15.3			30.9			47.5			1.0			N/A			N/A			N/A
01/01/18 to 12/31/18		1.2			N/A			N/A			16.0			31.7			50.1			1.0			N/A			N/A			N/A
01/01/19 to 12/31/19		1.0			0.4	%		N/A			4.8			39.9			52.0			1.9			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 16 for descriptions of the indexes.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2050 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
				1 Year						5 Years						10 Years
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		8.49	%		26.38	%		N/A			8.49	%		N/A			9.20	%		N/A
Investor A		8.37			26.11			19.49	%		8.23			7.07	%		8.93			8.34	%
Investor C		7.92			25.10			24.10			7.37			7.37			7.98			7.98
Class K		8.63			26.67			N/A			8.74			N/A			9.52			N/A
Class R		8.29			25.92			N/A			8.00			N/A			8.57			N/A
LifePath Dynamic 2050 Fund Custom Benchmark		9.08			26.88			N/A			8.41			N/A			9.63			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.75			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.36			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			8.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			5.21			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			13.54			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			11.83			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 16 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes. LifePath Dynamic 2050 Fund’s returns prior to March 31, 2018 are the returns of LifePath Dynamic 2050 Fund when its assets could be allocated to underlying funds that invest primarily in commodities. LifePath Dynamic 2050 Fund’s returns between December 14, 2015 and November 7, 2016 are the returns of LifePath Dynamic 2050 Fund when it incorporated different allocations in its glidepath and had a different investment strategy. LifePath Dynamic 2050 Fund’s returns prior to December 14, 2015 are the returns of LifePath Dynamic 2050 Fund under a different investment strategy. LifePath Dynamic 2050 Fund’s returns prior to November 28, 2014 are the returns of LifePath Dynamic 2050 Fund when it had a different glidepath and target asset allocation.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 13

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2060 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2060 Fund (“LifePath Dynamic 2060 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2060 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(b)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2060 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

^(c)  Commencement of operations.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index
05/31/17(a) to 12/31/17		1.0	%		N/A			4.3	%		15.3	%		30.9	%		47.5	%		1.0	%
01/01/18 to 12/31/18		1.0			N/A			N/A			16.1			31.8			50.1			1.0
01/01/19 to 12/31/19		1.0			0.1	%		N/A			4.8			40.1			52.0			2.0

^(a)  Commencement of operations.

See “About Fund Performance” on page 16 for descriptions of the indexes.

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2060 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
				1 Year						Since Inception (b)
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		8.54	%		26.47	%		N/A			10.36	%		N/A
Investor A		8.34			26.20			19.58	%		10.09			7.82	%
Investor C		7.95			25.09			24.09			9.20			9.20
Class K		8.62			26.74			N/A			10.58			N/A
Class R		8.32			25.92			N/A			9.87			N/A
LifePath Dynamic 2060 Fund Custom Benchmark		9.11			26.95			N/A			10.51			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.74			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			3.14			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			7.99			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			6.02			N/A
Russell 1000® Index		10.59			31.43			N/A			14.00			N/A
Russell 2000® Index		7.30			25.52			N/A			9.41			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 16 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes. LifePath Dynamic 2060 Fund’s returns prior to March 31, 2018 are the returns of LifePath Dynamic 2060 Fund when its assets could be allocated to underlying funds that invest primarily in commodities.

^(b)  The LifePath Dynamic Fund commenced operations on May 31, 2017.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 15

About Fund Performance

Institutional and Class K Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors.

Investor A Shares are subject to a maximum initial sales charge(front-end load) of 5.25% and a service fee of 0.25% per year (but no distribution fee). Certain redemptions of these shares may be subject to a contingent deferred sales charge (“CDSC”) where no initial sales charge was paid at the time of purchase. These shares are generally available through financial intermediaries.

Investor C Shares are subject to a 1.00% CDSC if redeemed within one year of purchase. In addition, these shares are subject to a distribution fee of 0.75% per year and a service fee of 0.25% per year. These shares are generally available through financial intermediaries. These shares automatically convert to Investor A Shares after approximately ten years. Except with respect to LifePath Dynamic 2060 Fund, Investor C Shares performance shown prior to the Investor C Shares inception date of May 3, 2010 is that of Institutional Shares (which have no distribution or service fees) and was restated to reflect Investor C Shares fees.

Class R Shares are not subject to any sales charge. These shares are subject to a distribution fee of 0.25% per year and a service fee of 0.25% per year. These shares are available only to certain employer-sponsored retirement plans. Except with respect to LifePath Dynamic 2060 Fund, Class R Shares performance shown prior to the Class R Shares inception date of May 3, 2010 is that of Institutional Shares (which have no distribution or service fees) and was restated to reflect Class R Shares fees.

Performance information reflects past performance and does not guarantee future results. Current performance may be lower or higher than the performance data quoted. Refer toblackrock.com to obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Figures shown in the performance tables on the previous pages assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend date. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of service, distribution and transfer agency fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (“BAL” or the “Administrator”), each LifePath Dynamic Fund’s administrator, has contractually agreed to waive and/or reimburse a portion of each LifePath Dynamic Fund’s expenses. Without such waiver and/or reimbursement, each LifePath Dynamic Fund’s performance would have been lower. With respect to each Fund’s contractual waiver, the Administrator is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See Note 4 of the Notes to Financial Statements for additional information on waivers and/or reimbursements.

The LifePath Dynamic Funds’ custom benchmarks are hypothetical representations of the performance of the respective LifePath Dynamic Fund’s asset classes according to their weightings as of the most recent quarter-end. The weightings of the various indexes that are included in the LifePath Dynamic Funds’ custom benchmarks are adjusted quarterly to reflect the LifePath Dynamic Funds’ changing asset allocations over time. As of December 31, 2019, the following indexes are used to calculate the LifePath Dynamic Funds’ custom benchmarks: Bloomberg Barclays U.S. Aggregate Bond Index, Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L), FTSE EPRA Nareit Developed Index, MSCI ACWI ex USA IMI Index, Russell 1000^® Index and Russell 2000^® Index, as applicable.

The Bloomberg Barclays U.S. Aggregate Bond Index is a widely recognized unmanaged market-weighted index, comprised of investment-grade corporate bonds rated BBB or better, mortgages and U.S. Treasury and U.S. Government agency issues with at least one year to maturity. The Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L) is an unmanaged index that measures the performance of the inflation-protected public obligations of the U.S. Treasury. The FTSE EPRA Nareit Developed Index is a global market capitalization weighted index composed of listed real estate securities from developed market countries in North America, Europe, and Asia. The MSCI ACWI ex USA IMI Index is a free float-adjusted market capitalization weighted index that measures the equity market performance of the developed (excluding the U.S.) and emerging investable market universe. The Russell 1000^® Index is an index that measures the performance of the large-cap segment of the U.S. equity universe. It is a subset of the Russell 3000^® Index and includes approximately 1,000 of the largest securities based on a combination of their market capitalization and current index membership. The Russell 1000^® Index represents approximately 92% of the total market capitalization of the Russell 3000^® Index. The Russell 2000^® Index is an unmanaged index that is a subset of the Russell 3000^® Index representing approximately 10% of the total market capitalization of that index. It includes approximately 2000 of the smallest securities based on a combination of their market cap and current index membership.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Disclosure of Expenses

Shareholders of each LifePath Dynamic Fund may incur the following charges: (a) transactional expenses, such as sales charges; and (b) operating expenses, including administration fees, service and distribution fees, including 12b-1 fees, acquired fund fees and expenses, and other fund expenses. The expense examples shown below (which are based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019) are intended to assist shareholders both in calculating expenses based on an investment in each LifePath Dynamic Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense examples provide information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their LifePath Dynamic Fund and share class under the heading entitled “Expenses Paid During the Period.”

The expense examples also provide information about hypothetical account values and hypothetical expenses based on a LifePath Dynamic Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in a LifePath Dynamic Fund and other funds, compare the 5% hypothetical examples with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense examples are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical examples are useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

Expense Examples

	Actual						Hypothetical (b)
	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
LifePath Dynamic Retirement Fund
Institutional	$	1,000.00	$	1,047.30	$	2.79	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,045.90		4.02		1,000.00		1,021.27		3.97		0.78
Investor C		1,000.00		1,041.60		8.03		1,000.00		1,017.34		7.93		1.56
Class K		1,000.00		1,048.40		1.70		1,000.00		1,023.54		1.68		0.33
Class R		1,000.00		1,043.90		5.10		1,000.00		1,020.21		5.04		0.99
LifePath Dynamic 2030 Fund
Institutional	$	1,000.00	$	1,067.10	$	2.81	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,065.70		4.11		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,061.10		8.26		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,067.70		1.82		1,000.00		1,023.44		1.79		0.35
Class R		1,000.00		1,063.90		5.20		1,000.00		1,020.16		5.09		1.00
LifePath Dynamic 2040 Fund
Institutional	$	1,000.00	$	1,081.00	$	2.83	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,078.60		4.14		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,075.00		8.32		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,081.70		1.78		1,000.00		1,023.49		1.73		0.34
Class R		1,000.00		1,078.20		5.24		1,000.00		1,020.16		5.09		1.00
LifePath Dynamic 2050 Fund
Institutional	$	1,000.00	$	1,084.90	$	2.84	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,083.70		4.15		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,079.20		8.33		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,086.30		1.79		1,000.00		1,023.49		1.73		0.34
Class R		1,000.00		1,082.90		5.25		1,000.00		1,020.16		5.09		1.00
LifePath Dynamic 2060 Fund
Institutional	$	1,000.00	$	1,085.40	$	2.84	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,083.40		4.15		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,079.50		8.44		1,000.00		1,017.09		8.19		1.61
Class K		1,000.00		1,086.20		1.89		1,000.00		1,023.39		1.84		0.36
Class R		1,000.00		1,083.20		5.20		1,000.00		1,020.21		5.04		0.99

^(a)  For each class of the LifePath Dynamic Funds, expenses are equal to the annualized net expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period shown). Because each LifePath Dynamic Fund invests all of its assets in a LifePath Dynamic Master Portfolio, the expense examples reflect the net expenses of both the LifePath Dynamic Fund and the LifePath Dynamic Master Portfolio in which it invests.

^(b)  Hypothetical 5% annual return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

DISCLOSURE OF EXPENSES 17

Derivative Financial Instruments

The LifePath Dynamic Master Portfolios may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The LifePath Dynamic Master Portfolios’ successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation a LifePath Dynamic Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The LifePath Dynamic Master Portfolios’ investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Assets and Liabilities

December 31, 2019

	BlackRock LifePath Dynamic Retirement Fund		BlackRock LifePath Dynamic 2030 Fund		BlackRock LifePath Dynamic 2040 Fund		BlackRock LifePath Dynamic 2050 Fund		BlackRock LifePath Dynamic 2060 Fund
ASSETS
Investments at value — from the applicable LifePath Dynamic Master Portfolio	$	408,508,193	$	350,827,109	$	289,474,849	$	113,818,194	$	4,285,474
Receivables:
Capital shares sold		392,908		751,934		583,514		479,675		3,820
Withdrawals from the LifePath Dynamic Master Portfolio		3,578,186		1,701,113		1,762,152		952,725		—
Prepaid expenses		—		—		—		—		632
Total assets		412,479,287		353,280,156		291,820,515		115,250,594		4,289,926
LIABILITIES
Payables:
Administration fees		215,046		183,133		149,497		58,671		—
Capital gains distributions		96,333		318,806		322,319		127,179		23,780
Capital shares redeemed		3,971,094		2,453,047		2,345,666		1,432,400		—
Contributions to the LifePath Dynamic Master Portfolio		—		—		—		—		3,820
Income dividend distributions		63,358		73,507		71,802		31,002		22,757
Professional fees		20,617		11,007		11,002		11,004		10,993
Service and distribution fees		56,587		50,427		41,281		18,742		177
Total liabilities		4,423,035		3,089,927		2,941,567		1,678,998		61,527
NET ASSETS	$	408,056,252	$	350,190,229	$	288,878,948	$	113,571,596	$	4,228,399
NET ASSETS CONSIST OF
Paid-in capital	$	301,184,954	$	320,978,236	$	223,128,625	$	91,924,742	$	3,823,364
Accumulated earnings		106,871,298		29,211,993		65,750,323		21,646,854		405,035
NET ASSETS	$	408,056,252	$	350,190,229	$	288,878,948	$	113,571,596	$	4,228,399
NET ASSET VALUE
Institutional
Net assets	$	99,249,012	$	73,529,998	$	60,508,460	$	16,870,031	$	236,623
Shares outstanding(a)		8,993,923		5,388,381		3,514,717		827,277		20,627
Net asset value	$	11.04	$	13.65	$	17.22	$	20.39	$	11.47
Investor A
Net assets	$	234,757,219	$	212,100,301	$	173,102,939	$	75,985,618	$	389,938
Shares outstanding(a)		24,515,825		16,295,895		11,208,551		3,740,690		34,022
Net asset value	$	9.58	$	13.02	$	15.44	$	20.31	$	11.46
Investor C
Net assets	$	3,846,438	$	3,745,629	$	3,275,879	$	1,774,294	$	32,860
Shares outstanding(a)		353,884		280,781		193,994		88,616		2,869
Net asset value	$	10.87	$	13.34	$	16.89	$	20.02	$	11.45
Class K
Net assets	$	64,912,912	$	56,168,281	$	47,987,029	$	16,383,278	$	3,384,022
Shares outstanding(a)		5,907,680		4,125,404		2,771,140		800,620		294,755
Net asset value	$	10.99	$	13.62	$	17.32	$	20.46	$	11.48
				��
Class R
Net assets	$	5,290,671	$	4,646,020	$	4,004,641	$	2,558,375	$	184,956
Shares outstanding(a)		484,766		345,163		235,317		126,490		16,137
Net asset value	$	10.91	$	13.46	$	17.02	$	20.23	$	11.46

^(a)  Unlimited number of shares authorized, no par value.

See notes to financial statements.

FINANCIAL STATEMENTS 19

Statements of Operations

Year Ended December 31, 2019

	BlackRock LifePath Dynamic Retirement Fund			BlackRock LifePath Dynamic 2030 Fund			BlackRock LifePath Dynamic 2040 Fund			BlackRock LifePath Dynamic 2050 Fund			BlackRock LifePath Dynamic 2060 Fund
INVESTMENT INCOME
Net investment income allocated from the applicable LifePath Dynamic Master Portfolio:
Dividends — affiliated	$	2,597,163		$	5,865,075		$	5,814,217		$	2,361,673		$	66,117
Interest — affiliated		2,492,411			2,942,446			1,001,227			165,374			4,349
Dividends — unaffiliated		4,876			302,607			394,145			174,671			5,812
Securities lending income — affiliated — net		5,928			19,704			20,632			10,126			—
Foreign taxes withheld		(1,619	)		(26,446	)		(36,781	)		(15,511	)		(414	)
Expenses		(931,741	)		(2,041,505	)		(1,697,797	)		(673,237	)		(42,764	)
Fees waived		615,805			1,361,335			1,154,375			463,682			37,240
Total investment income		4,782,823			8,423,216			6,650,018			2,486,778			70,340
FUND EXPENSES
Administration — class specific		511,026			1,093,849			886,226			347,385			4,758
Reorganization costs		20,750			—			—			—			—
Service and distribution — class specific		247,560			608,194			489,252			220,913			902
Professional		11,001			11,000			11,000			11,000			10,981
Miscellaneous		1,142			2,143			543			400			57
			��
Total expenses		791,479			1,715,186			1,387,021			579,698			16,698
Less fees waived and/or reimbursed by the Administrator/Manager		(31,751	)		(11,000	)		(11,000	)		(11,000	)		(10,981	)
Total expenses after fees waived and/or reimbursed		759,728			1,704,186			1,376,021			568,698			5,717
Net investment income		4,023,095			6,719,030			5,273,997			1,918,080			64,623
REALIZED AND UNREALIZED GAIN ALLOCATED FROM THE APPLICABLE LIFEPATH DYNAMIC MASTER PORTFOLIO
Net realized gain from investments, futures contracts, forward foreign currency exchange contracts, foreign currency transactions and payment from affiliate		7,324,884			23,238,353			22,572,490			8,239,144			153,586
Net change in unrealized appreciation (depreciation) on investments, futures contracts, forward foreign currency exchange contracts and foreign currency translations		12,174,336			35,508,869			33,542,118			13,666,366			449,266
Net realized and unrealized gain		19,499,220			58,747,222			56,114,608			21,905,510			602,852
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	23,522,315		$	65,466,252		$	61,388,605		$	23,823,590		$	667,475

See notes to financial statements.

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	BlackRock LifePath Dynamic Retirement Fund						BlackRock LifePath Dynamic 2030 Fund
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	4,023,095		$	2,702,904		$	6,719,030		$	6,847,085
Net realized gain		7,324,884			3,307,468			23,238,353			19,220,309
Net change in unrealized appreciation (depreciation)		12,174,336			(9,880,327	)		35,508,869			(44,082,511	)
Net increase (decrease) in net assets resulting from operations		23,522,315			(3,869,955	)		65,466,252			(18,015,117	)
DISTRIBUTIONS(a)
Institutional		(1,832,284	)		(2,406,882	)		(4,440,293	)		(8,118,699	)
Investor A		(4,663,112	)		(6,584,642	)		(13,286,373	)		(27,107,204	)
Investor C		(53,190	)		(57,097	)		(196,209	)		(446,801	)
Class K		(1,145,772	)		(1,355,265	)		(3,252,332	)		(3,444,124	)
Class R		(87,526	)		(89,635	)		(251,450	)		(293,206	)
Decrease in net assets resulting from distributions to shareholders		(7,781,884	)		(10,493,521	)		(21,426,657	)		(39,410,034	)
CAPITAL SHARE TRANSACTIONS
Net increase (decrease) in net assets derived from capital share transactions		284,854,744			(16,360,203	)		(461,025	)		(31,919,120	)
NET ASSETS
Total increase (decrease) in net assets		300,595,175			(30,723,679	)		43,578,570			(89,344,271	)
Beginning of year		107,461,077			138,184,756			306,611,659			395,955,930
End of year	$	408,056,252		$	107,461,077		$	350,190,229		$	306,611,659

^(a) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 21

Statements of Changes in Net Assets  (continued)

	BlackRock LifePath Dynamic 2040 Fund						BlackRock LifePath Dynamic 2050 Fund
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	5,273,997		$	5,150,084		$	1,918,080		$	1,599,726
Net realized gain		22,572,490			17,885,075			8,239,144			6,552,689
Net change in unrealized appreciation (depreciation)		33,542,118			(43,537,526	)		13,666,366			(16,388,946	)
Net increase (decrease) in net assets resulting from operations		61,388,605			(20,502,367	)		23,823,590			(8,236,531	)
DISTRIBUTIONS(a)
Institutional		(3,800,345	)		(6,790,780	)		(968,990	)		(1,828,736	)
Investor A		(12,069,597	)		(24,073,191	)		(4,381,579	)		(9,761,167	)
Investor C		(178,940	)		(308,963	)		(89,702	)		(168,958	)
Class K		(2,914,363	)		(3,709,835	)		(867,152	)		(614,153	)
Class R		(233,267	)		(277,484	)		(139,113	)		(222,605	)
Decrease in net assets resulting from distributions to shareholders		(19,196,512	)		(35,160,253	)		(6,446,536	)		(12,595,619	)
CAPITAL SHARE TRANSACTIONS
Net increase (decrease) in net assets derived from capital share transactions		(2,960,737	)		(12,925,013	)		7,213,616			(11,756,039	)
NET ASSETS
Total increase (decrease) in net assets		39,231,356			(68,587,633	)		24,590,670			(32,588,189	)
Beginning of year		249,647,592			318,235,225			88,980,926			121,569,115
End of year	$	288,878,948		$	249,647,592		$	113,571,596		$	88,980,926

^(a) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets  (continued)

	BlackRock LifePath Dynamic 2060 Fund
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	64,623		$	43,578
Net realized gain		153,586			6,701
Net change in unrealized appreciation (depreciation)		449,266			(246,243	)
Net increase (decrease) in net assets resulting from operations		667,475			(195,964	)
DISTRIBUTIONS(a)
Institutional		(5,909	)		(1,528	)
Investor A		(8,512	)		(4,804	)
Investor C		(653	)		(1,642	)
Class K		(91,308	)		(152,339	)
Class R		(3,748	)		(1,407	)
Decrease in net assets resulting from distributions to shareholders		(110,130	)		(161,720	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		1,671,724			135,001
NET ASSETS
Total increase (decrease) in net assets		2,229,069			(222,683	)
Beginning of year		1,999,330			2,222,013
End of year	$	4,228,399		$	1,999,330

^(a) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 23

Financial Highlights

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic Retirement Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.69		$	11.00		$	10.78		$	10.33		$	11.07
Net investment income(a)		0.28			0.25			0.19			0.18			0.16
Net realized and unrealized gain (loss)		1.35			(0.64	)		1.05			0.43			(0.33	)
Net increase (decrease) from investment operations		1.63			(0.39	)		1.24			0.61			(0.17	)
Distributions(b)
From net investment income		(0.19	)		(0.27	)		(0.15	)		(0.16	)		(0.20	)
From net realized gain		(0.09	)		(0.65	)		(0.87	)		(0.00	)(c)		(0.36	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.28	)		(0.92	)		(1.02	)		(0.16	)		(0.57	)
Net asset value, end of year	$	11.04		$	9.69		$	11.00		$	10.78		$	10.33
Total Return(d)
Based on net asset value		16.91	%		(3.68	)%		11.68	%		5.91	%		(1.52	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.57	%		0.58	%		0.57	%		0.58	%		0.75	%
Total expenses after fees waived and/or reimbursed		0.55	%		0.57	%		0.56	%		0.58	%		0.70	%
Net investment income		2.61	%		2.26	%		1.66	%		1.66	%		1.48	%
Supplemental Data
Net assets, end of year (000)	$	99,249		$	25,343		$	38,119		$	60,166		$	141,034
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(g)		35	%		38	%		6	%		37	%		21	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.39	%		0.37	%		0.38	%		0.35	%		0.31	%
Investments in underlying funds		0.08	%		0.09	%		0.12	%		0.10	%		0.09	%

^(g) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic Retirement Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	8.45		$	9.72		$	9.64		$	9.25		$	9.99
Net investment income(a)		0.23			0.20			0.14			0.14			0.12
Net realized and unrealized gain (loss)		1.16			(0.57	)		0.94			0.39			(0.30	)
Net increase (decrease) from investment operations		1.39			(0.37	)		1.08			0.53			(0.18	)
Distributions(b)
From net investment income		(0.17	)		(0.25	)		(0.13	)		(0.14	)		(0.19	)
From net realized gain		(0.09	)		(0.65	)		(0.87	)		(0.00	)(c)		(0.36	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.26	)		(0.90	)		(1.00	)		(0.14	)		(0.56	)
Net asset value, end of year	$	9.58		$	8.45		$	9.72		$	9.64		$	9.25
Total Return(d)
Based on net asset value		16.56	%		(3.93	)%		11.40	%		5.78	%		(1.89	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.82	%		0.83	%		0.82	%		0.84	%		1.00	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.82	%		0.82	%		0.83	%		0.95	%
Net investment income		2.43	%		2.05	%		1.46	%		1.49	%		1.25	%
Supplemental Data
Net assets, end of year (000)	$	234,757		$	65,509		$	81,900		$	81,929		$	102,207
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(g)		35	%		38	%		6	%		37	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Amount is greater than $(0.005) per share.

^(d) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.39	%		0.37	%		0.37	%		0.35	%		0.31	%
Investments in underlying funds		0.08	%		0.09	%		0.12	%		0.10	%		0.09	%

^(g) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 25

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic Retirement Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.57		$	10.87		$	10.67		$	10.22		$	10.97
Net investment income(a)		0.18			0.13			0.07			0.07			0.06
Net realized and unrealized gain (loss)		1.30			(0.63	)		1.03			0.44			(0.34	)
Net increase (decrease) from investment operations		1.48			(0.50	)		1.10			0.51			(0.28	)
Distributions(b)
From net investment income		(0.09	)		(0.15	)		(0.04	)		(0.06	)		(0.10	)
From net realized gain		(0.09	)		(0.65	)		(0.86	)		(0.00	)(c)		(0.36	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.18	)		(0.80	)		(0.90	)		(0.06	)		(0.47	)
Net asset value, end of year	$	10.87		$	9.57		$	10.87		$	10.67		$	10.22
Total Return(d)
Based on net asset value		15.54	%		(4.67	)%		10.47	%		4.97	%		(2.56	)%
Ratios to Average Net Assets(e)(f)
Total expenses		1.62	%		1.63	%		1.62	%		1.63	%		1.76	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.62	%		1.62	%		1.63	%		1.70	%
Net investment income		1.66	%		1.20	%		0.65	%		0.66	%		0.56	%
Supplemental Data
Net assets, end of year (000)	$	3,846		$	672		$	1,034		$	1,068		$	1,573
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(g)		35	%		38	%		6	%		37	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Amount is greater than $(0.005) per share.

^(d) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.39	%		0.37	%		0.38	%		0.35	%		0.31	%
Investments in underlying funds		0.08	%		0.09	%		0.12	%		0.10	%		0.09	%

^(g) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic Retirement Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.65		$	10.96		$	10.75		$	10.30		$	11.05
Net investment income(a)		0.32			0.27			0.22			0.21			0.21
Net realized and unrealized gain (loss)		1.32			(0.64	)		1.03			0.43			(0.35	)
Net increase (decrease) from investment operations		1.64			(0.37	)		1.25			0.64			(0.14	)
Distributions(b)
From net investment income		(0.21	)		(0.29	)		(0.17	)		(0.19	)		(0.24	)
From net realized gain		(0.09	)		(0.65	)		(0.87	)		(0.00	)(c)		(0.36	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.30	)		(0.94	)		(1.04	)		(0.19	)		(0.61	)
Net asset value, end of year	$	10.99		$	9.65		$	10.96		$	10.75		$	10.30
Total Return(d)
Based on net asset value		17.07	%		(3.47	)%		11.87	%		6.20	%		(1.28	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.37	%		0.38	%		0.37	%		0.39	%		0.42	%
Total expenses after fees waived and/or reimbursed		0.35	%		0.37	%		0.36	%		0.38	%		0.42	%
Net investment income		2.99	%		2.54	%		1.93	%		2.02	%		1.96	%
Supplemental Data
Net assets, end of year (000)	$	64,913		$	14,901		$	15,965		$	11,571		$	8,577
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(g)		35	%		38	%		6	%		37	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Amount is greater than $(0.005) per share.

^(d) Where applicable, assumes the reinvestment of distributions.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.39	%		0.37	%		0.38	%		0.34	%		0.30	%
Investments in underlying funds		0.08	%		0.09	%		0.12	%		0.10	%		0.09	%

^(g) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 27

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic Retirement Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.60		$	10.91		$	10.71		$	10.26		$	11.01
Net investment income(a)		0.23			0.20			0.14			0.15			0.10
Net realized and unrealized gain (loss)		1.32			(0.64	)		1.03			0.42			(0.33	)
Net increase (decrease) from investment operations		1.55			(0.44	)		1.17			0.57			(0.23	)
Distributions(b)
From net investment income		(0.15	)		(0.22	)		(0.10	)		(0.12	)		(0.15	)
From net realized gain		(0.09	)		(0.65	)		(0.87	)		(0.00	)(c)		(0.36	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.24	)		(0.87	)		(0.97	)		(0.12	)		(0.52	)
Net asset value, end of year	$	10.91		$	9.60		$	10.91		$	10.71		$	10.26
Total Return(d)
Based on net asset value		16.24	%		(4.11	)%		11.11	%		5.59	%		(2.10	)%
Ratios to Average Net Assets(e)(f)
Total expenses		1.02	%		1.03	%		1.02	%		1.04	%		1.25	%
Total expenses after fees waived and/or reimbursed		1.00	%		1.02	%		1.02	%		1.04	%		1.19	%
Net investment income		2.19	%		1.87	%		1.27	%		1.40	%		0.99	%
Supplemental Data
Net assets, end of year (000)	$	5,291		$	1,036		$	1,167		$	928		$	656
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(g)		35	%		38	%		6	%		37	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Amount is greater than $(0.005) per share.

^(d) Where applicable, assumes the reinvestment of distributions.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.39	%		0.37	%		0.38	%		0.35	%		0.31	%
Investments in underlying funds		0.08	%		0.09	%		0.12	%		0.10	%		0.09	%

^(g) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2030 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.90		$	14.26		$	13.79		$	13.20		$	14.71
Net investment income(a)		0.29			0.29			0.24			0.23			0.22
Net realized and unrealized gain (loss)		2.32			(1.04	)		2.13			0.72			(0.51	)
Net increase (decrease) from investment operations		2.61			(0.75	)		2.37			0.95			(0.29	)
Distributions(b)
From net investment income		(0.30	)		(0.31	)		(0.25	)		(0.25	)		(0.25	)
From net realized gain		(0.56	)		(1.30	)		(1.65	)		(0.11	)		(0.96	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.86	)		(1.61	)		(1.90	)		(0.36	)		(1.22	)
Net asset value, end of year	$	13.65		$	11.90		$	14.26		$	13.79		$	13.20
Total Return(c)
Based on net asset value		22.07	%		(5.48	)%		17.67	%		7.24	%		(2.05	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.56	%		0.56	%		0.55	%		0.56	%		0.70	%
Total expenses after fees waived and/or reimbursed		0.55	%		0.56	%		0.55	%		0.56	%		0.70	%
Net investment income		2.18	%		2.01	%		1.64	%		1.73	%		1.46	%
Supplemental Data
Net assets, end of year (000)	$	73,530		$	59,749		$	90,086		$	141,217		$	222,491
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		32	%		29	%		21	%		61	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.41	%		0.39	%		0.39	%		0.37	%		0.37	%
Investments in underlying funds		0.10	%		0.11	%		0.14	%		0.12	%		0.14	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 29

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2030 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.39		$	13.72		$	13.33		$	12.78		$	14.28
Net investment income(a)		0.24			0.25			0.20			0.20			0.18
Net realized and unrealized gain (loss)		2.22			(1.00	)		2.06			0.68			(0.49	)
Net increase (decrease) from investment operations		2.46			(0.75	)		2.26			0.88			(0.31	)
Distributions(b)
From net investment income		(0.27	)		(0.28	)		(0.22	)		(0.22	)		(0.22	)
From net realized gain		(0.56	)		(1.30	)		(1.65	)		(0.11	)		(0.96	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.83	)		(1.58	)		(1.87	)		(0.33	)		(1.19	)
Net asset value, end of year	$	13.02		$	11.39		$	13.72		$	13.33		$	12.78
Total Return(c)
Based on net asset value		21.72	%		(5.69	)%		17.43	%		6.93	%		(2.25	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.81	%		0.81	%		0.80	%		0.81	%		0.95	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.81	%		0.80	%		0.81	%		0.95	%
Net investment income		1.89	%		1.80	%		1.44	%		1.53	%		1.28	%
Supplemental Data
Net assets, end of year (000)	$	212,100		$	212,050		$	265,932		$	271,354		$	298,579
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		32	%		29	%		21	%		61	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.41	%		0.39	%		0.39	%		0.37	%		0.36	%
Investments in underlying funds		0.10	%		0.11	%		0.14	%		0.12	%		0.14	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2030 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.65		$	14.01		$	13.58		$	13.01		$	14.52
Net investment income(a)		0.14			0.15			0.10			0.10			0.08
Net realized and unrealized gain (loss)		2.27			(1.04	)		2.08			0.69			(0.51	)
Net increase (decrease) from investment operations		2.41			(0.89	)		2.18			0.79			(0.43	)
Distributions(b)
From net investment income		(0.16	)		(0.17	)		(0.10	)		(0.11	)		(0.11	)
From net realized gain		(0.56	)		(1.30	)		(1.65	)		(0.11	)		(0.96	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.72	)		(1.47	)		(1.75	)		(0.22	)		(1.08	)
Net asset value, end of year	$	13.34		$	11.65		$	14.01		$	13.58		$	13.01
Total Return(c)
Based on net asset value		20.76	%		(6.53	)%		16.48	%		6.12	%		(3.01	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.61	%		1.61	%		1.60	%		1.61	%		1.71	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.61	%		1.60	%		1.61	%		1.71	%
Net investment income		1.08	%		1.05	%		0.67	%		0.74	%		0.56	%
Supplemental Data
Net assets, end of year (000)	$	3,746		$	4,117		$	3,888		$	3,217		$	3,173
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		32	%		29	%		21	%		61	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.41	%		0.37	%		0.38	%		0.35	%		0.31	%
Investments in underlying funds		0.10	%		0.09	%		0.12	%		0.10	%		0.09	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 31

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2030 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.88		$	14.24		$	13.77		$	13.19		$	14.70
Net investment income(a)		0.34			0.32			0.28			0.28			0.29
Net realized and unrealized gain (loss)		2.29			(1.04	)		2.12			0.69			(0.52	)
Net increase (decrease) from investment operations		2.63			(0.72	)		2.40			0.97			(0.23	)
Distributions(b)
From net investment income		(0.33	)		(0.34	)		(0.28	)		(0.28	)		(0.31	)
From net realized gain		(0.56	)		(1.30	)		(1.65	)		(0.11	)		(0.96	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.89	)		(1.64	)		(1.93	)		(0.39	)		(1.28	)
Net asset value, end of year	$	13.62		$	11.88		$	14.24		$	13.77		$	13.19
Total Return(c)
Based on net asset value		22.27	%		(5.28	)%		17.96	%		7.42	%		(1.66	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.36	%		0.36	%		0.35	%		0.36	%		0.37	%
Total expenses after fees waived and/or reimbursed		0.36	%		0.36	%		0.35	%		0.36	%		0.37	%
Net investment income		2.52	%		2.27	%		1.91	%		2.04	%		2.01	%
Supplemental Data
Net assets, end of year (000)	$	56,168		$	28,121		$	33,881		$	29,419		$	16,171
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		32	%		29	%		21	%		61	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.41	%		0.39	%		0.39	%		0.37	%		0.36	%
Investments in underlying funds		0.10	%		0.11	%		0.14	%		0.12	%		0.14	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2030 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.76		$	14.12		$	13.67		$	13.09		$	14.60
Net investment income(a)		0.24			0.24			0.18			0.17			0.15
Net realized and unrealized gain (loss)		2.27			(1.05	)		2.10			0.71			(0.50	)
Net increase (decrease) from investment operations		2.51			(0.81	)		2.28			0.88			(0.35	)
Distributions(b)
From net investment income		(0.25	)		(0.25	)		(0.18	)		(0.19	)		(0.19	)
From net realized gain		(0.56	)		(1.30	)		(1.65	)		(0.11	)		(0.96	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.81	)		(1.55	)		(1.83	)		(0.30	)		(1.16	)
Net asset value, end of year	$	13.46		$	11.76		$	14.12		$	13.67		$	13.09
Total Return(c)
Based on net asset value		21.44	%		(5.92	)%		17.16	%		6.74	%		(2.50	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.01	%		1.01	%		1.00	%		1.01	%		1.20	%
Total expenses after fees waived and/or reimbursed		1.01	%		1.01	%		0.99	%		1.01	%		1.20	%
Net investment income		1.78	%		1.70	%		1.21	%		1.30	%		1.07	%
Supplemental Data
Net assets, end of year (000)	$	4,646		$	2,575		$	2,169		$	2,751		$	3,178
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		32	%		29	%		21	%		61	%		21	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.41	%		0.39	%		0.39	%		0.37	%		0.36	%
Investments in underlying funds		0.10	%		0.14	%		0.14	%		0.12	%		0.14	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 33

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2040 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	14.62		$	18.04		$	17.15		$	16.24		$	18.37
Net investment income(a)		0.35			0.34			0.29			0.29			0.27
Net realized and unrealized gain (loss)		3.39			(1.65	)		3.27			1.00			(0.67	)
Net increase (decrease) from investment operations		3.74			(1.31	)		3.56			1.29			(0.40	)
Distributions(b)
From net investment income		(0.37	)		(0.33	)		(0.36	)		(0.32	)		(0.30	)
From net realized gain		(0.77	)		(1.78	)		(2.31	)		(0.06	)		(1.43	)
Total distributions		(1.14	)		(2.11	)		(2.67	)		(0.38	)		(1.73	)
Net asset value, end of year	$	17.22		$	14.62		$	18.04		$	17.15		$	16.24
Total Return(c)
Based on net asset value		25.72	%		(7.49	)%		21.44	%		7.97	%		(2.29	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.55	%		0.55	%		0.54	%		0.54	%		0.67	%
Total expenses after fees waived and/or reimbursed		0.55	%		0.55	%		0.54	%		0.54	%		0.67	%
Net investment income		2.10	%		1.87	%		1.57	%		1.74	%		1.46	%
Supplemental Data
Net assets, end of year (000)	$	60,508		$	48,056		$	67,358		$	121,623		$	186,357
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		35	%		39	%		30	%		77	%		19	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.42	%		0.40	%		0.41	%		0.38	%		0.39	%
Investments in underlying funds		0.12	%		0.13	%		0.16	%		0.14	%		0.17	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2040 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	13.22		$	16.53		$	15.91		$	15.10		$	17.22
Net investment income(a)		0.27			0.27			0.24			0.24			0.23
Net realized and unrealized gain (loss)		3.06			(1.50	)		3.01			0.92			(0.65	)
Net increase (decrease) from investment operations		3.33			(1.23	)		3.25			1.16			(0.42	)
Distributions(b)
From net investment income		(0.34	)		(0.30	)		(0.32	)		(0.29	)		(0.27	)
From net realized gain		(0.77	)		(1.78	)		(2.31	)		(0.06	)		(1.43	)
Total distributions		(1.11	)		(2.08	)		(2.63	)		(0.35	)		(1.70	)
Net asset value, end of year	$	15.44		$	13.22		$	16.53		$	15.91		$	15.10
Total Return(c)
Based on net asset value		25.29	%		(7.70	)%		21.17	%		7.69	%		(2.57	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.80	%		0.80	%		0.79	%		0.79	%		0.93	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.80	%		0.79	%		0.79	%		0.92	%
Net investment income		1.81	%		1.66	%		1.41	%		1.55	%		1.31	%
Supplemental Data
Net assets, end of year (000)	$	173,103		$	168,678		$	204,321		$	201,118		$	221,048
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		35	%		39	%		30	%		77	%		19	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.42	%		0.40	%		0.41	%		0.38	%		0.38	%
Investments in underlying funds		0.12	%		0.13	%		0.16	%		0.14	%		0.17	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 35

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2040 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	14.37		$	17.77		$	16.93		$	16.05		$	18.19
Net investment income(a)		0.17			0.15			0.11			0.13			0.11
Net realized and unrealized gain (loss)		3.32			(1.62	)		3.21			0.96			(0.69	)
Net increase (decrease) from investment operations		3.49			(1.47	)		3.32			1.09			(0.58	)
Distributions(b)
From net investment income		(0.20	)		(0.15	)		(0.17	)		(0.15	)		(0.13	)
From net realized gain		(0.77	)		(1.78	)		(2.31	)		(0.06	)		(1.43	)
Total distributions		(0.97	)		(1.93	)		(2.48	)		(0.21	)		(1.56	)
Net asset value, end of year	$	16.89		$	14.37		$	17.77		$	16.93		$	16.05
Total Return(c)
Based on net asset value		24.35	%		(8.47	)%		20.21	%		6.82	%		(3.28	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.60	%		1.60	%		1.59	%		1.60	%		1.68	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.60	%		1.59	%		1.59	%		1.68	%
Net investment income		1.05	%		0.86	%		0.62	%		0.78	%		0.61	%
Supplemental Data
Net assets, end of year (000)	$	3,276		$	2,541		$	3,017		$	2,567		$	2,492
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		35	%		39	%		30	%		77	%		19	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.42	%		0.40	%		0.41	%		0.38	%		0.38	%
Investments in underlying funds		0.12	%		0.13	%		0.16	%		0.14	%		0.17	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2040 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	14.70		$	18.13		$	17.23		$	16.32		$	18.47
Net investment income(a)		0.41			0.38			0.35			0.34			0.40
Net realized and unrealized gain (loss)		3.38			(1.66	)		3.26			0.99			(0.75	)
Net increase (decrease) from investment operations		3.79			(1.28	)		3.61			1.33			(0.35	)
Distributions(b)
From net investment income		(0.40	)		(0.37	)		(0.40	)		(0.36	)		(0.37	)
From net realized gain		(0.77	)		(1.78	)		(2.31	)		(0.06	)		(1.43	)
Total distributions		(1.17	)		(2.15	)		(2.71	)		(0.42	)		(1.80	)
Net asset value, end of year	$	17.32		$	14.70		$	18.13		$	17.23		$	16.32
Total Return(c)
Based on net asset value		25.96	%		(7.31	)%		21.66	%		8.19	%		(1.98	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.35	%		0.35	%		0.34	%		0.34	%		0.36	%
Total expenses after fees waived and/or reimbursed		0.35	%		0.35	%		0.34	%		0.34	%		0.35	%
Net investment income		2.42	%		2.09	%		1.87	%		2.07	%		2.21	%
Supplemental Data
Net assets, end of year (000)	$	47,987		$	28,294		$	40,407		$	33,644		$	14,470
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		35	%		39	%		30	%		77	%		19	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.42	%		0.40	%		0.41	%		0.38	%		0.38	%
Investments in underlying funds		0.12	%		0.13	%		0.16	%		0.14	%		0.17	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 37

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2040 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	14.48		$	17.89		$	17.04		$	16.15		$	18.29
Net investment income(a)		0.28			0.25			0.22			0.23			0.21
Net realized and unrealized gain (loss)		3.34			(1.63	)		3.22			0.98			(0.69	)
Net increase (decrease) from investment operations		3.62			(1.38	)		3.44			1.21			(0.48	)
Distributions(b)
From net investment income		(0.31	)		(0.25	)		(0.28	)		(0.26	)		(0.23	)
From net realized gain		(0.77	)		(1.78	)		(2.31	)		(0.06	)		(1.43	)
Total distributions		(1.08	)		(2.03	)		(2.59	)		(0.32	)		(1.66	)
Net asset value, end of year	$	17.02		$	14.48		$	17.89		$	17.04		$	16.15
Total Return(c)
Based on net asset value		25.10	%		(7.92	)%		20.86	%		7.50	%		(2.75	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.01	%		1.00	%		0.99	%		1.00	%		1.17	%
Total expenses after fees waived and/or reimbursed		1.00	%		1.00	%		0.99	%		0.99	%		1.17	%
Net investment income		1.70	%		1.41	%		1.22	%		1.40	%		1.13	%
Supplemental Data
Net assets, end of year (000)	$	4,005		$	2,078		$	3,132		$	2,190		$	1,389
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		35	%		39	%		30	%		77	%		19	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.42	%		0.40	%		0.41	%		0.38	%		0.38	%
Investments in underlying funds		0.12	%		0.13	%		0.16	%		0.14	%		0.17	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2050 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	17.13		$	21.54		$	18.58		$	17.53		$	19.59
Net investment income(a)		0.41			0.36			0.33			0.31			0.28
Net realized and unrealized gain (loss)		4.09			(2.07	)		3.89			1.12			(0.74	)
Net increase (decrease) from investment operations		4.50			(1.71	)		4.22			1.43			(0.46	)
Distributions(b)
From net investment income		(0.42	)		(0.42	)		(0.40	)		(0.38	)		(0.30	)
From net realized gain		(0.82	)		(2.28	)		(0.86	)		—			(1.30	)
Total distributions		(1.24	)		(2.70	)		(1.26	)		(0.38	)		(1.60	)
Net asset value, end of year	$	20.39		$	17.13		$	21.54		$	18.58		$	17.53
Total Return(c)
Based on net asset value		26.38	%		(8.27	)%		22.85	%		8.19	%		(2.46	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.56	%		0.56	%		0.54	%		0.55	%		0.66	%
Total expenses after fees waived and/or reimbursed		0.55	%		0.55	%		0.53	%		0.54	%		0.65	%
Net investment income		2.07	%		1.68	%		1.59	%		1.71	%		1.42	%
Supplemental Data
Net assets, end of year (000)	$	16,870		$	11,376		$	18,804		$	31,857		$	40,444
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		42	%		43	%		35	%		70	%		36	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.42	%		0.42	%		0.40	%		0.42	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.15	%		0.19	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, LargeCap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 39

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2050 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	17.06		$	21.47		$	18.54		$	17.49		$	19.56
Net investment income(a)		0.34			0.31			0.29			0.27			0.27
Net realized and unrealized gain (loss)		4.10			(2.07	)		3.86			1.11			(0.77	)
Net increase (decrease) from investment operations		4.44			(1.76	)		4.15			1.38			(0.50	)
Distributions(b)
From net investment income		(0.37	)		(0.37	)		(0.36	)		(0.33	)		(0.27	)
From net realized gain		(0.82	)		(2.28	)		(0.86	)		—			(1.30	)
Total distributions		(1.19	)		(2.65	)		(1.22	)		(0.33	)		(1.57	)
Net asset value, end of year	$	20.31		$	17.06		$	21.47		$	18.54		$	17.49
Total Return(c)
Based on net asset value		26.11	%		(8.51	)%		22.48	%		7.95	%		(2.65	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.81	%		0.81	%		0.79	%		0.80	%		0.92	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.80	%		0.78	%		0.79	%		0.91	%
Net investment income		1.76	%		1.47	%		1.43	%		1.51	%		1.38	%
Supplemental Data
Net assets, end of year (000)	$	75,986		$	70,181		$	82,949		$	69,168		$	70,473
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		42	%		43	%		35	%		70	%		36	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.42	%		0.42	%		0.40	%		0.40	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.15	%		0.19	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, LargeCap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2050 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	16.86		$	21.26		$	18.38		$	17.35		$	19.43
Net investment income(a)		0.20			0.14			0.14			0.13			0.13
Net realized and unrealized gain (loss)		4.02			(2.05	)		3.81			1.09			(0.77	)
Net increase (decrease) from investment operations		4.22			(1.91	)		3.95			1.22			(0.64	)
Distributions(b)
From net investment income		(0.24	)		(0.21	)		(0.21	)		(0.19	)		(0.14	)
From net realized gain		(0.82	)		(2.28	)		(0.86	)		—			(1.30	)
Total distributions		(1.06	)		(2.49	)		(1.07	)		(0.19	)		(1.44	)
Net asset value, end of year	$	20.02		$	16.86		$	21.26		$	18.38		$	17.35
Total Return(c)
Based on net asset value		25.10	%		(9.25	)%		21.53	%		7.08	%		(3.41	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.61	%		1.61	%		1.59	%		1.60	%		1.68	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.60	%		1.58	%		1.59	%		1.67	%
Net investment income		1.01	%		0.68	%		0.66	%		0.72	%		0.66	%
Supplemental Data
Net assets, end of year (000)	$	1,774		$	1,299		$	1,211		$	744		$	717
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		42	%		43	%		35	%		70	%		36	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.42	%		0.42	%		0.40	%		0.40	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.15	%		0.19	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, LargeCap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 41

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2050 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	17.18		$	21.59		$	18.63		$	17.58		$	19.66
Net investment income(a)		0.50			0.37			0.39			0.36			0.39
Net realized and unrealized gain (loss)		4.06			(2.05	)		3.88			1.11			(0.78	)
Net increase (decrease) from investment operations		4.56			(1.68	)		4.27			1.47			(0.39	)
Distributions(b)
From net investment income		(0.46	)		(0.45	)		(0.45	)		(0.42	)		(0.39	)
From net realized gain		(0.82	)		(2.28	)		(0.86	)		—			(1.30	)
Total distributions		(1.28	)		(2.73	)		(1.31	)		(0.42	)		(1.69	)
Net asset value, end of year	$	20.46		$	17.18		$	21.59		$	18.63		$	17.58
Total Return(c)
Based on net asset value		26.67	%		(8.11	)%		23.07	%		8.43	%		(2.10	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.36	%		0.36	%		0.34	%		0.34	%		0.34	%
Total expenses after fees waived and/or reimbursed		0.35	%		0.35	%		0.33	%		0.33	%		0.33	%
Net investment income		2.54	%		1.69	%		1.89	%		2.00	%		2.01	%
Supplemental Data
Net assets, end of year (000)	$	16,383		$	4,504		$	17,057		$	13,388		$	1,647
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		42	%		43	%		35	%		70	%		36	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.42	%		0.42	%		0.40	%		0.40	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.15	%		0.19	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, LargeCap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2050 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	17.00		$	21.42		$	18.50		$	17.45		$	19.53
Net investment income(a)		0.31			0.27			0.25			0.23			0.23
Net realized and unrealized gain (loss)		4.08			(2.08	)		3.85			1.11			(0.78	)
Net increase (decrease) from investment operations		4.39			(1.81	)		4.10			1.34			(0.55	)
Distributions(b)
From net investment income		(0.34	)		(0.33	)		(0.32	)		(0.29	)		(0.23	)
From net realized gain		(0.82	)		(2.28	)		(0.86	)		—			(1.30	)
Total distributions		(1.16	)		(2.61	)		(1.18	)		(0.29	)		(1.53	)
Net asset value, end of year	$	20.23		$	17.00		$	21.42		$	18.50		$	17.45
Total Return(c)
Based on net asset value		25.92	%		(8.74	)%		22.24	%		7.75	%		(2.92	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.01	%		1.01	%		0.99	%		1.00	%		1.17	%
Total expenses after fees waived and/or reimbursed		1.00	%		1.00	%		0.98	%		0.99	%		1.16	%
Net investment income		1.57	%		1.29	%		1.22	%		1.31	%		1.20	%
Supplemental Data
Net assets, end of year (000)	$	2,558		$	1,620		$	1,548		$	1,324		$	1,550
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		42	%		43	%		35	%		70	%		36	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c) Where applicable, assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.42	%		0.42	%		0.40	%		0.40	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.15	%		0.19	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, LargeCap Index Master Portfolio, Master SmallCap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 43

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2060 Fund
	Institutional
	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Net asset value, beginning of period	$	9.34		$	11.02		$	10.00
Net investment income(b)		0.26			0.19			0.13
Net realized and unrealized gain (loss)		2.20			(1.13	)		1.04
Net increase (decrease) from investment operations		2.46			(0.94	)		1.17
Distributions(c)
From net investment income		(0.21	)		(0.24	)		(0.15	)
From net realized gain		(0.12	)		(0.50	)		—
Total distributions		(0.33	)		(0.74	)		(0.15	)
Net asset value, end of period	$	11.47		$	9.34		$	11.02
Total Return(d)
Based on net asset value		26.47	%(e)		(8.64	)%		11.71	%(f)
Ratios to Average Net Assets(g)(h)
Total expenses		0.92	%		1.10	%		1.03	%(i)(j)
Total expenses after fees waived and/or reimbursed		0.54	%		0.55	%		0.56	%(i)
Net investment income		2.39	%		1.73	%		2.07	%(i)
Supplemental Data
Net assets, end of period (000)	$	237		$	19		$	27
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(k)		44	%		58	%		35	%

^(a) Commencement of operations.

^(b) Based on average shares outstanding.

^(c) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d) Where applicable, assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which impacted the Fund’s total return. Excluding the payment from an affiliate, the Fund’s total return is 26.36%.

^(f) Aggregate total return.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(h)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Allocated fees waived		1.37	%		1.50	%		1.88	%
Investments in underlying funds		0.13	%		0.14	%		0.23	%

⁽ⁱ⁾  Annualized.

^(j)  Audit costs were not annualized in the calculation of the expense ratio. If these expenses were annualized, the total expenses would have been 1.37%.

^(k)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2060 Fund (continued)
	Investor A
	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Net asset value, beginning of period	$	9.33		$	11.02		$	10.00
Net investment income(b)		0.23			0.17			0.11
Net realized and unrealized gain (loss)		2.21			(1.13	)		1.04
Net increase (decrease) from investment operations		2.44			(0.96	)		1.15
Distributions(c)
From net investment income		(0.19	)		(0.23	)		(0.13	)
From net realized gain		(0.12	)		(0.50	)		—
Total distributions		(0.31	)		(0.73	)		(0.13	)
Net asset value, end of period	$	11.46		$	9.33		$	11.02
Total Return(d)
Based on net asset value		26.20	%(e)		(8.90	)%		11.56	%(f)
Ratios to Average Net Assets(g)(h)
Total expenses		1.17	%		1.36	%		1.29	%(i)(j)
Total expenses after fees waived and/or reimbursed		0.79	%		0.80	%		0.82	%(i)
Net investment income		2.11	%		1.61	%		1.76	%(i)
Supplemental Data
Net assets, end of period (000)	$	390		$	75		$	28
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(k)		44	%		58	%		35	%

^(a) Commencement of operations.

^(b) Based on average shares outstanding.

^(c) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which impacted the Fund’s total return. Excluding the payment from an affiliate, the Fund’s total return is 26.09%.

^(f) Aggregate total return.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(h)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Allocated fees waived		1.37	%		1.50	%		1.88	%
Investments in underlying funds		0.13	%		0.14	%		0.23	%

⁽ⁱ⁾  Annualized.

^(j)  Audit costs were not annualized in the calculation of the expense ratio. If these expenses were annualized, the total expenses would have been 1.62%.

^(k)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 45

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2060 Fund (continued)
	Investor C
	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Net asset value, beginning of period	$	9.34		$	11.02		$	10.00
Net investment income(b)		0.11			0.08			0.06
Net realized and unrealized gain (loss)		2.23			(1.13	)		1.05
Net increase (decrease) from investment operations		2.34			(1.05	)		1.11
Distributions(c)
From net investment income		(0.11	)		(0.13	)		(0.09	)
From net realized gain		(0.12	)		(0.50	)		—
Total distributions		(0.23	)		(0.63	)		(0.09	)
Net asset value, end of period	$	11.45		$	9.34		$	11.02
Total Return(d)
Based on net asset value		25.09	%(e)		(9.60	)%		11.07	%(f)
Ratios to Average Net Assets(g)(h)
Total expenses		2.03	%		2.16	%		2.08	%(i)(j)
Total expenses after fees waived and/or reimbursed		1.61	%		1.60	%		1.61	%(i)
Net investment income		1.07	%		0.71	%		0.94	%(i)
Supplemental Data
Net assets, end of period (000)	$	33		$	25		$	28
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(k)		44	%		58	%		35	%

^(a) Commencement of operations.

^(b) Based on average shares outstanding.

^(c) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d) Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which had no impact on the Fund’s total return.

^(f) Aggregate total return.

^(g) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(h) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Allocated fees waived		1.37	%		1.50	%		1.88	%
Investments in underlying funds		0.13	%		0.14	%		0.23	%

⁽ⁱ⁾ Annualized.

^(j) Audit costs were not annualized in the calculation of the expense ratio. If these expenses were annualized, the total expenses would have been 2.41%.

^(k) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2060 Fund (continued)
	Class K
	Year Ended December 31,						Period from 05/31/2017 (a) to 12/31/17
	2019			2018
Net asset value, beginning of period	$	9.34		$	11.02		$	10.00
Net investment income(b)		0.26			0.22			0.13
Net realized and unrealized gain (loss)		2.23			(1.13	)		1.05
Net increase (decrease) from investment operations		2.49			(0.91	)		1.18
Distributions(c)
From net investment income		(0.23	)		(0.27	)		(0.16	)
From net realized gain		(0.12	)		(0.50	)		—
Total distributions		(0.35	)		(0.77	)		(0.16	)
Net asset value, end of period	$	11.48		$	9.34		$	11.02
Total Return(d)
Based on net asset value		26.74	%(e)		(8.45	)%		11.82	%(f)
Ratios to Average Net Assets(g)(h)
Total expenses		0.77	%		0.90	%(h)		0.82	%(i)(j)
Total expenses after fees waived and/or reimbursed		0.36	%		0.35	%(h)		0.35	%(i)
Net investment income		2.40	%		1.96	%(h)		2.11	%(i)
Supplemental Data
Net assets, end of period (000)	$	3,384		$	1,862		$	2,116
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(k)		44	%		58	%		35	%

^(a) Commencement of operations.

^(b) Based on average shares outstanding.

^(c) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d) Where applicable, assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which impacted the Fund’s total return. Excluding the payment from an affiliate, the Fund’s total return is 26.64%.

^(f) Aggregate total return.

^(g) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(h) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,						Period from 05/31/2017 (a) to 12/31/17
	2019			2018
Allocated fees waived		1.37	%		1.50	%		1.88	%
Investments in underlying funds		0.13	%		0.14	%		0.23	%

⁽ⁱ⁾ Annualized.

^(j) Audit costs were not annualized in the calculation of the expense ratio. If these expenses were annualized, the total expenses would have been 1.15%.

^(k) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 47

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2060 Fund (continued)
	Class R
	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Net asset value, beginning of period	$	9.34		$	11.02		$	10.00
Net investment income(b)		0.40			0.15			0.10
Net realized and unrealized gain (loss)		2.02			(1.13	)		1.04
Net increase (decrease) from investment operations		2.42			(0.98	)		1.14
Distributions(c)
From net investment income		(0.18	)		(0.20	)		(0.12	)
From net realized gain		(0.12	)		(0.50	)		—
Total distributions		(0.30	)		(0.70	)		(0.12	)
Net asset value, end of period	$	11.46		$	9.34		$	11.02
Total Return(d)
Based on net asset value		25.92	%(e)		(9.05	)%		11.40	%(f)
Ratios to Average Net Assets(g)(h)
Total expenses		1.37	%		1.55	%		1.49	%(i)(j)
Total expenses after fees waived and/or reimbursed		0.99	%		1.00	%		1.01	%(i)
Net investment income		3.67	%		1.30	%		1.55	%(i)
Supplemental Data
Net assets, end of period (000)	$	185		$	19		$	22
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(k)		44	%		58	%		35	%

^(a) Commencement of operations.

^(b) Based on average shares outstanding.

^(c) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d) Where applicable, assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which impacted the Fund’s total return. Excluding the payment from an affiliate, the Fund’s total return is 25.81%.

^(f) Aggregate total return.

^(g) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(h) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Allocated fees waived		1.37	%		1.50	%		1.88	%
Investments in underlying funds		0.13	%		0.14	%		0.23	%

⁽ⁱ⁾ Annualized.

^(j) Audit costs were not annualized in the calculation of the expense ratio. If these expenses were annualized, the total expenses would have been 1.82%.

^(k) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

48 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. The following, each of which is a series of the Trust, are referred to herein collectively as the “LifePath Dynamic Funds” or individually as a “LifePath Dynamic Fund”:

Fund Name	Herein Referred To As	Diversification Classification
BlackRock LifePath® Dynamic Retirement Fund	LifePath Dynamic Retirement Fund	Diversified
BlackRock LifePath® Dynamic 2030 Fund	LifePath Dynamic 2030 Fund	Diversified
BlackRock LifePath® Dynamic 2040 Fund	LifePath Dynamic 2040 Fund	Diversified
BlackRock LifePath® Dynamic 2050 Fund	LifePath Dynamic 2050 Fund	Diversified
BlackRock LifePath® Dynamic 2060 Fund	LifePath Dynamic 2060 Fund	Diversified

Each LifePath Dynamic Fund seeks to achieve its investment objective by investing all of its assets in a corresponding series of Master Investment Portfolio (“MIP”): LifePath^® Dynamic Retirement Master Portfolio, LifePath^® Dynamic 2030 Master Portfolio, LifePath^® Dynamic 2040 Master Portfolio, LifePath^® Dynamic 2050 Master Portfolio and LifePath^® Dynamic 2060 Master Portfolio (each, a “LifePath Dynamic Master Portfolio” and together, the “LifePath Dynamic Master Portfolios”). MIP is an affiliate of the Trust. Each LifePath Dynamic Master Portfolio has the same investment objective and strategies as its corresponding LifePath Dynamic Fund. The value of each LifePath Dynamic Fund’s investment in its corresponding LifePath Dynamic Master Portfolio reflects the LifePath Dynamic Fund’s proportionate interest in the net assets of the LifePath Dynamic Master Portfolio. The performance of each LifePath Dynamic Fund is directly affected by the performance of the LifePath Dynamic Master Portfolios. At December 31, 2019, the percentage of each LifePath Dynamic Master Portfolio owned by the corresponding LifePath Dynamic Fund was approximately 100% for each of the LifePath Dynamic Funds, respectively. The financial statements of the LifePath Dynamic Master Portfolios, including the Schedules of Investments, are included elsewhere in this report and should be read in conjunction with the LifePath Dynamic Funds’ financial statements.

Each LifePath Dynamic Fund offers multiple classes of shares. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that certain classes bear expenses related to the shareholder servicing and distribution of such shares. Institutional and Class K Shares are sold without a sales charge and only to certain eligible investors. Investor A and Investor C Shares are generally available through financial intermediaries. Class R Shares are sold without a sales charge and only to certain employer-sponsored retirement plans. Investor A, Investor C, and Class R Shares bear certain expenses related to shareholder servicing of such shares, and Investor C and Class R Shares also bear certain expenses related to the distribution of such shares. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures (except that Investor C shareholders may vote on material changes to the Investor A Shares distribution and service plan). The Board of Trustees of the Trust and Board of Trustees of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

Share Class	Initial Sales Charge	CDSC			Conversion Privilege
Institutional, Class K and Class R Shares	No		No		None
Investor A Shares	Yes		No	(a)	None
Investor C Shares	No		Yes	(b)	To Investor A Shares after approximately 10 years

^(a)  Investor A Shares may be subject to a contingent deferred sales charge (“CDSC”) for certain redemptions where no initial sales charge was paid at the time of purchase.

^(b) A CDSC of 1.00% is assessed on certain redemptions of Investor C Shares made within one year after purchase.

The LifePath Dynamic Funds, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, are included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

On November 12-13, 2019, the Board approved a proposal pursuant to which each LifePath Dynamic Fund will cease to invest in its corresponding LifePath Dynamic Master Portfolio as part of a “master-feeder” structure and instead operate as a stand-alone fund. In connection with this change, the Trust, on behalf of each LifePath Dynamic Fund, will enter into a management agreement with BFA, the terms of which will be substantially the same as the current management agreement between BFA and each corresponding LifePath Dynamic Master Portfolio, including the management fee rate. The change into a stand-alone structure will not create a taxable event for the LifePath Dynamic Funds or their shareholders. These changes are expected to be effective on or about March 9, 2020.

Reorganization: The Board of the Trust approved the reorganization of the BlackRock LifePath^® Dynamic 2020 Fund (the “Target Fund” or “LifePath Dynamic 2020 Fund”) into LifePath Dynamic Retirement Fund. As a result, LifePath Dynamic Retirement Fund acquired substantially all of the assets and assumed substantially all of the liabilities of the Target Fund in exchange for an equal aggregate value of newly-issued shares of LifePath Dynamic Retirement Fund.

Each shareholder of the Target Fund received shares of LifePath Dynamic Retirement Fund in an amount equal to the aggregate net asset value (“NAV”) of such shareholder’s Target Fund shares, as determined at the close of business on November 15, 2019, less the costs of the Target Fund’s reorganization.

NOTESTO FINANCIAL STATEMENTS 49

Notes to Financial Statements  (continued)

The reorganization was accomplished by atax-free exchange of shares of LifePath Dynamic Retirement Fund in the following amounts and at the following conversion ratios:

Target Fund’s Share Class	Shares Prior to Reorganization	Conversion Ratio	LifePath Dynamic Retirement Fund’s Share Class	Shares of the LifePath Dynamic Retirement Fund
Institutional	2,487,549	1.36476524	Institutional	3,394,920
Investor A	12,752,524	1.42279915	Investor A	18,144,280
Investor C	226,655	1.36270095	Investor C	308,863
Class K	2,538,644	1.36311365	Class K	3,460,460
Class R	205,044	1.36914646	Class R	280,735

The Target Fund’s net assets and composition of net assets on November 15, 2019, the valuation date of the reorganization were as follows:

	Target Fund
Net assets	$	255,264,099
Paid-in-capital		180,125,770
Accumulated earnings		75,138,329

For financial reporting purposes, assets received and shares issued by LifePath Dynamic Retirement Fund were recorded at fair value. However, the cost basis of the investments received from the Target Fund was carried forward to align ongoing reporting of LifePath Dynamic Retirement Fund’s realized and unrealized gains and losses with amounts distributable to shareholders for tax purposes.

The net assets of LifePath Dynamic Retirement Fund before the reorganization were $147,849,209. The aggregate net assets of LifePath Dynamic Retirement Fund immediately after the reorganization amounted to $403,113,308. The Target Fund’s fair value and cost of investments prior to the reorganization was as follows:

Target Fund	Fair Value of Investments
LifePath® Dynamic 2020 Fund	$	255,395,569

The purpose of these transactions was to combine two funds managed by the Manager with substantially similar (but not identical) investment objectives, investment policies, strategies, risks and restrictions. The reorganization was atax-free event and was effective on November 18, 2019.

Assuming the reorganization had been completed on January 1, 2019, the beginning of the fiscal reporting period of LifePath Dynamic Retirement Fund, the pro forma results of operations for the year ended December 31, 2019, are as follows:

• Net investment income: $7,845,164

• Net realized and change in unrealized gain on investments: $72,886,892

• Net increase in net assets resulting from operations: $80,732,056

Because the combined investment portfolios have been managed as a single integrated portfolio since the reorganization was completed, it is not practicable to separate the amounts of revenue and earnings of the Target Fund that have been included in LifePath Dynamic Retirement Fund’s Statements of Operations since November 18, 2019.

The Manager reimbursed the LifePath Dynamic Retirement Fund $20,750, which is included in fees waived and/or reimbursed by the Administrator/Manager in the Statements of Operations.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. Each LifePath Dynamic Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from each LifePath Dynamic Master Portfolio are accounted for on a trade date basis. Each LifePath Dynamic Fund records its proportionate share of LifePath Dynamic Master Portfolio’s income, expenses and realized and unrealized gains and losses on a daily basis. Realized and unrealized gains and losses are adjusted utilizing partnership tax allocation rules. In addition, the LifePath Dynamic Funds accrue their own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions from net investment income are declared and paid quarterly. Distributions of capital gains are recorded on theex-dividend date and made at least annually. The portion of distributions, if any, that exceeds a fund’s current and accumulated earnings and profits, as measured on a tax basis, constitute anon-taxable return of capital. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

50 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Indemnifications:In the normal course of business, a LifePath Dynamic Fund enters into contracts that contain a variety of representations that provide general indemnification. A LifePath Dynamic Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against a LifePath Dynamic Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to a LifePath Dynamic Fund or its classes are charged to that LifePath Dynamic Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the LifePath Dynamic Funds and other shared expenses prorated to the LifePath Dynamic Funds are allocated daily to each class based on their relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: Each LifePath Dynamic Fund’s policy is to value its financial instruments at fair value. Each LifePath Dynamic Fund records its investment in its corresponding LifePath Dynamic Master Portfolio at fair value based on each LifePath Dynamic Fund’s proportionate interest in the net assets of its corresponding LifePath Dynamic Master Portfolio. Valuation of securities held by the LifePath Dynamic Master Portfolios is discussed in Note 3 of the LifePath Dynamic Master Portfolios’ Notes to Financial Statements, which are included elsewhere in this report.

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration: The Trust, on behalf of the LifePath Dynamic Funds, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL” or the “Administrator”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the LifePath Dynamic Funds’ ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the LifePath Dynamic Funds. BAL is entitled to receive for these administrative services an annual fee of 0.35% based on the average daily net assets of each LifePath Dynamic Funds’ Institutional and Investor A Shares, 0.40% of the average daily net assets of Investor C Shares, 0.15% of the average daily net assets of Class K Shares and 0.30% of the average daily net assets of Class R Shares.

From time to time, BAL may waive such fees in whole or in part. Any such waiver will reduce the expenses of the LifePath Dynamic Funds and, accordingly, have a favorable impact on its performance. BAL may delegate certain of its administration duties tosub-administrators.

For the year ended December 31, 2019, the following table shows the class specific administration fees borne directly by each share class of each LifePath Dynamic Fund:

	Institutional		Investor A		Investor C		Class K		Class R		Total
LifePath Dynamic Retirement Fund		153,781		315,110		4,430		30,894		6,811		511,026
LifePath Dynamic 2030 Fund		240,801		771,468		15,785		55,310		10,485		1,093,849
LifePath Dynamic 2040 Fund		192,215		623,999		11,641		49,836		8,535		886,226
LifePath Dynamic 2050 Fund		50,672		273,014		6,063		11,308		6,328		347,385
LifePath Dynamic 2060 Fund		391		600		117		3,541		109		4,758

Service and Distribution Fees: The Trust, on behalf of the LifePath Dynamic Funds, entered into a Distribution Agreement and a Distribution and Service Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Pursuant to the Distribution and Service Plan and in accordance with Rule12b-1 under the 1940 Act, each LifePath Dynamic Fund pays BRIL ongoing service and distribution fees. The fees are accrued daily and paid monthly at annual rates based upon the average daily net assets of the relevant share class of each LifePath Dynamic Fund as follows:

	Service Fees			Distribution Fees
Investor A		0.25	%		—	%
Investor C		0.25			0.75
Class R		0.25			0.25

BRIL and broker-dealers, pursuant tosub-agreements with BRIL, provide shareholder servicing and distribution services to the LifePath Dynamic Funds. The ongoing service and/or distribution fee compensates/reimburses BRIL and each broker-dealer for providing shareholder servicing and/or distribution related services to shareholders.

For the year ended December 31, 2019, the following table shows the class specific service and distribution fees borne directly by each share class of each LifePath Dynamic Fund:

Service and Distribution Fees	Investor A		Investor C		Class R		Total
LifePath Dynamic Retirement Fund		225,103		11,077		11,380		247,560
LifePath Dynamic 2030 Fund		551,140		39,475		17,579		608,194
LifePath Dynamic 2040 Fund		445,806		29,124		14,322		489,252
LifePath Dynamic 2050 Fund		195,138		15,177		10,598		220,913
LifePath Dynamic 2060 Fund		428		292		182		902

Other Fees: For the year ended December 31, 2019, affiliates earned underwriting discounts, direct commissions and dealer concessions on sales of each LifePath Dynamic Fund’s Investor A Shares as follows:

	LifePath Dynamic Retirement Fund		LifePath Dynamic 2030 Fund		LifePath Dynamic 2040 Fund		LifePath Dynamic 2050 Fund		LifePath Dynamic 2060 Fund
Investor A	$	896	$	1,654	$	1,503	$	390	$	129

NOTESTO FINANCIAL STATEMENTS 51

Notes to Financial Statements  (continued)

For the year ended December 31, 2019, affiliates received CDSCs as follows:

	LifePath Dynamic Retirement Fund		LifePath Dynamic 2030 Fund		LifePath Dynamic 2040 Fund		LifePath Dynamic 2050 Fund		LifePath Dynamic 2060 Fund
Investor C	$	2	$	114	$	5	$	83	$	—

Expense Limitations, Waivers and Reimbursements:The fees and expenses of the Trust’s trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the LifePath Dynamic Funds’ independent registered public accounting firm (together, the “independent expenses”) are paid directly by the LifePath Dynamic Funds. BAL has contractually agreed to reimburse the LifePath Dynamic Funds or provide an offsetting credit against the administration fees paid by the LifePath Dynamic Funds in an amount equal to these independent expenses through April 30, 2029 for each LifePath Dynamic Fund other than the LifePath Dynamic Retirement Fund (for which the contractual arrangement is in effect through April 30, 2030). These amounts are included in fees waived and/or reimbursed by the Administrator/Manager in the Statements of Operations. For the year ended December 31, 2019, the LifePath Dynamic Funds waived the following amounts:

	Amounts Waived
LifePath Dynamic Retirement Fund	$	11,001
LifePath Dynamic 2030 Fund		11,000
LifePath Dynamic 2040 Fund		11,000
LifePath Dynamic 2050 Fund		11,000
LifePath Dynamic 2060 Fund		10,981

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), each LifePath Dynamic Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by each LifePath Dynamic Fund’s investment policies and restrictions. Each LifePath Dynamic Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the LifePath Dynamic Funds did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the LifePath Dynamic Funds are directors and/or officers of BlackRock, Inc. or its affiliates.

5. INCOME TAX INFORMATION

It is each LifePath Dynamic Fund’s policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

Each LifePath Dynamic Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on each LifePath Dynamic Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019 except for LifePath Dynamic 2060 Fund, which remains open for the period ended December 31, 2017 through the year ended December 31, 2019. The statutes of limitations on each LifePath Dynamic Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the LifePath Dynamic Funds as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the LifePath Dynamic Funds’ financial statements.

The tax character of distributions paid was as follows:

	LifePath Dynamic Retirement Fund		LifePath Dynamic 2030 Fund		LifePath Dynamic 2040 Fund		LifePath Dynamic 2050 Fund		LifePath Dynamic 2060 Fund
Ordinary income
12/31/19	$	4,972,523	$	10,145,955	$	7,378,388	$	2,117,634	$	66,758
12/31/18		5,599,775		22,280,914		19,166,944		6,643,719		111,385
Long-term capital gains
12/31/19		2,809,361		11,280,702		11,818,124		4,328,902		43,372
12/31/18		4,893,746		17,129,120		15,993,309		5,951,900		50,335
12/31/19	$	7,781,884	$	21,426,657	$	19,196,512	$	6,446,536	$	110,130
12/31/18	$	10,493,521	$	39,410,034	$	35,160,253	$	12,595,619	$	161,720

52 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

As of period end, the tax components of accumulated earnings (loss) were as follows:

	LifePath Dynamic Retirement Fund		LifePath Dynamic 2030 Fund		LifePath Dynamic 2040 Fund		LifePath Dynamic 2050 Fund		LifePath Dynamic 2060 Fund
Undistributed ordinary income	$	1,544,335	$	2,365,609	$	2,347,361	$	918,961	$	1,820
Undistributed long-term capital gains		1,411,916		2,059,455		2,002,590		725,240		34,726
Net unrealized gains (losses)(a)		103,915,047		24,786,929		61,400,372		20,002,653		368,489
	$	106,871,298	$	29,211,993	$	65,750,323	$	21,646,854	$	405,035

^(a)  The difference between book-basis andtax-basis net unrealized gains were attributable primarily to the timing and recognition of partnership income.

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic Retirement Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		3,863,406		$	41,070,163			2,866,473		$	31,024,293
Shares issued in reinvestment of distributions		167,180			1,831,558			239,094			2,405,195
Shares issued resulting from reorganization		3,394,920			37,345,777			—			—
Shares redeemed		(1,046,012	)		(10,953,828	)		(3,956,542	)		(43,163,858	)
Net increase (decrease)		6,379,494		$	69,293,670			(850,975	)	$	(9,734,370	)
Investor A
Shares sold and automatic conversion of shares		987,245		$	9,095,344			894,821		$	8,574,231
Shares issued in reinvestment of distributions		480,070			4,663,053			751,052			6,584,641
Shares issued resulting from reorganization		18,144,280			173,602,186			—			—
Shares redeemed		(2,848,090	)		(26,762,487	)		(2,322,442	)		(22,315,745	)
Net increase (decrease)		16,763,505		$	160,598,096			(676,569	)	$	(7,156,873	)
Investor C
Shares sold		14,242		$	150,018			33,013		$	355,463
Shares issued in reinvestment of distributions		4,903			53,190			5,764			56,977
Shares issued resulting from reorganization		308,863			3,346,906			—			—
Shares redeemed and automatic conversion of shares		(44,329	)		(474,374	)		(63,695	)		(685,852	)
Net increase (decrease)		283,679		$	3,075,740			(24,918	)	$	(273,412	)
Class K
Shares sold		1,693,814		$	18,113,468			454,171		$	4,912,038
Shares issued in reinvestment of distributions		104,860			1,145,771			135,646			1,355,266
Shares issued resulting from reorganization		3,460,460			37,915,971			—			—
Shares redeemed		(895,505	)		(9,335,172	)		(502,455	)		(5,464,385	)
Net increase		4,363,629		$	47,840,038			87,362		$	802,919
Class R
Shares sold		234,424		$	2,490,823			58,956		$	635,653
Shares issued in reinvestment of distributions		8,070			87,526			9,034			89,585
Shares issued resulting from reorganization		280,735			3,053,259			—			—
Shares redeemed		(146,362	)		(1,584,408	)		(67,070	)		(723,705	)
Net increase		376,867		$	4,047,200			920		$	1,533
Total Net Increase (Decrease)		28,167,174		$	284,854,744			(1,464,180	)	$	(16,360,203	)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2030 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		1,142,794		$	14,866,930			1,415,872		$	20,180,716
Shares issued in reinvestment of distributions		319,164			4,437,150			646,592			8,092,824
Shares redeemed		(1,092,964	)		(14,418,701	)		(3,358,711	)		(47,018,732	)
Net increase (decrease)		368,994		$	4,885,379			(1,296,247	)	$	(18,745,192	)

NOTESTO FINANCIAL STATEMENTS 53

Notes to Financial Statements  (continued)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2030 Fund	Shares			Amount			Shares			Amount
Investor A
Shares sold and automatic conversion of shares		1,485,272		$	18,789,169			1,005,027		$	13,682,162
Shares issued in reinvestment of distributions		1,011,486			13,286,087			2,277,646			27,106,662
Shares redeemed		(4,821,546	)		(61,812,220	)		(4,043,458	)		(54,971,534	)
Net decrease		(2,324,788	)	$	(29,736,964	)		(760,785	)	$	(14,182,710	)
Investor C
Shares sold		85,912		$	1,117,954			98,595		$	1,338,702
Shares issued in reinvestment of distributions		14,678			195,494			36,989			445,397
Shares redeemed and automatic conversion of shares		(173,128	)		(2,232,664	)		(59,841	)		(831,518	)
Net increase (decrease)		(72,538	)	$	(919,216	)		75,743		$	952,581
Class K
Shares sold		2,347,274		$	31,269,292			623,568		$	8,810,189
Shares issued in reinvestment of distributions		239,426			3,252,332			278,123			3,444,124
Shares redeemed		(828,822	)		(10,903,875	)		(913,582	)		(13,052,294	)
Net increase (decrease)		1,757,878		$	23,617,749			(11,891	)	$	(797,981	)
Class R
Shares sold		311,393		$	4,143,690			90,948		$	1,251,160
Shares issued in reinvestment of distributions		18,720			251,388			24,097			293,087
Shares redeemed		(203,907	)		(2,703,051	)		(49,651	)		(690,065	)
Net increase		126,206		$	1,692,027			65,394		$	854,182
Total Net Decrease		(144,248	)	$	(461,025	)		(1,927,786	)	$	(31,919,120	)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2040 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		586,053		$	9,610,563			736,859		$	13,313,279
Shares issued in reinvestment of distributions		221,734			3,800,103			441,045			6,790,331
Shares redeemed		(579,744	)		(9,404,448	)		(1,624,875	)		(28,589,557	)
Net increase (decrease)		228,043		$	4,006,218			(446,971	)	$	(8,485,947	)
Investor A
Shares sold and automatic conversion of shares		946,617		$	14,240,480			932,113		$	15,239,536
Shares issued in reinvestment of distributions		784,498			12,069,407			1,734,381			24,072,835
Shares redeemed		(3,286,059	)		(49,628,617	)		(2,265,572	)		(36,934,464	)
Net increase (decrease)		(1,554,944	)	$	(23,318,730	)		400,922		$	2,377,907
Investor C
Shares sold		45,702		$	695,462			43,535		$	769,794
Shares issued in reinvestment of distributions		7,369			178,593			20,621			307,900
Shares redeemed and automatic conversion of shares		(35,941	)		(583,383	)		(57,089	)		(1,002,122	)
Net increase		17,130		$	290,672			7,067		$	75,572
Class K
Shares sold		1,265,420		$	21,335,365			578,699		$	10,437,852
Shares issued in reinvestment of distributions		168,918			2,914,364			240,641			3,709,834
Shares redeemed		(587,810	)		(9,775,123	)		(1,123,506	)		(20,424,291	)
Net increase (decrease)		846,528		$	14,474,606			(304,166	)	$	(6,276,605	)
Class R
Shares sold		245,587		$	4,035,332			68,773		$	1,204,701
Shares issued in reinvestment of distributions		8,406			232,497			18,201			277,328
Shares redeemed		(162,180	)		(2,681,332	)		(118,530	)		(2,097,969	)
Net increase (decrease)		91,813		$	1,586,497			(31,556	)	$	(615,940	)
Total Net Decrease		(371,430	)	$	(2,960,737	)		(374,704	)	$	(12,925,013	)

54 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2050 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		255,731		$	4,925,072			283,749		$	6,079,668
Shares issued in reinvestment of distributions		47,746			968,338			100,332			1,827,322
Shares redeemed		(140,480	)		(2,701,199	)		(592,884	)		(12,398,432	)
Net increase (decrease)		162,997		$	3,192,211			(208,803	)	$	(4,491,442	)
Investor A
Shares sold and automatic conversion of shares		579,158		$	11,247,472			441,499		$	9,429,787
Shares issued in reinvestment of distributions		216,845			4,381,579			544,631			9,761,145
Shares redeemed		(1,169,044	)		(23,085,853	)		(735,442	)		(15,732,745	)
Net increase (decrease)		(373,041	)	$	(7,456,802	)		250,688		$	3,458,187
Investor C
Shares sold		28,365		$	546,659			31,288		$	658,114
Shares issued in reinvestment of distributions		4,490			89,702			9,619			168,958
Shares redeemed and automatic conversion of shares		(21,314	)		(408,361	)		(20,782	)		(439,221	)
Net increase		11,541		$	228,000			20,125		$	387,851
Class K
Shares sold		587,117		$	11,539,516			133,927		$	2,888,969
Shares issued in reinvestment of distributions		42,498			867,152			34,151			614,153
Shares redeemed		(91,192	)		(1,785,230	)		(696,001	)		(15,056,171	)
Net increase (decrease)		538,423		$	10,621,438			(527,923	)	$	(11,553,049	)
Class R
Shares sold		125,657		$	2,481,279			45,804		$	967,469
Shares issued in reinvestment of distributions		6,906			139,113			12,473			222,600
Shares redeemed		(101,357	)		(1,991,623	)		(35,285	)		(747,655	)
Net increase		31,206		$	628,769			22,992		$	442,414
Total Net Increase (Decrease)		371,126		$	7,213,616			(442,921	)	$	(11,756,039	)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2060 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		30,550		$	331,568			113		$	1,272
Shares issued in reinvestment of distributions		463			5,243			3			32
Shares redeemed		(12,433	)		(134,847	)		(542	)		(6,118	)
Net increase (decrease)		18,580		$	201,964			(426	)	$	(4,814	)
Investor A
Shares sold and automatic conversion of shares		25,986		$	278,403			5,197		$	57,903
Shares issued in reinvestment of distributions		695			7,898			354			3,346
Shares redeemed		(695	)		(7,596	)		(94	)		(927	)
Net increase		25,986		$	278,705			5,457		$	60,322
Investor C
Shares sold		215		$	2,327			96		$	1,000
Shares issued in reinvestment of distributions		17			193			39			372
Shares redeemed and automatic conversion of shares		(1	)		(15	)		(11	)		(103	)
Net increase		231		$	2,505			124		$	1,269
Class K
Shares sold		98,722		$	1,063,779			7,352		$	79,112
Shares issued in reinvestment of distributions		2,151			24,617			449			4,279
Shares redeemed		(5,436	)		(59,386	)		(493	)		(5,174	)
Net increase		95,437		$	1,029,010			7,308		$	78,217

NOTESTO FINANCIAL STATEMENTS 55

Notes to Financial Statements  (continued)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2060 Fund	Shares			Amount			Shares		Amount
Class R
Shares sold		15,961		$	180,750			—	$	—
Shares issued in reinvestment of distributions		276			3,157			1		7
Shares redeemed		(2,111	)		(24,367	)		—		—
Net increase		14,126		$	159,540			1	$	7
Total Net Increase		154,360		$	1,671,724			12,464	$	135,001

As of December 31, 2019, shares of the LifePath Dynamic Funds owned by BlackRock HoldCo 2, Inc., an affiliate of the LifePath Dynamic Funds, were as follows:

	LifePath Dynamic 2060 Fund
Institutional		2,000
Investor A		2,000
Investor C		2,000
Class K		192,000
Class R		2,000

8. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the LifePath Dynamic Funds through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

56 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm BlackRock Funds III

To the Board of Trustees of

BlackRock Funds III and Shareholders of BlackRock LifePath^® Dynamic Retirement Fund, BlackRock LifePath^® Dynamic 2030 Fund, BlackRock LifePath^® Dynamic 2040 Fund, BlackRock LifePath^® Dynamic 2050 Fund and BlackRock LifePath^® Dynamic 2060 Fund

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities of BlackRock LifePath^® Dynamic Retirement Fund, BlackRock LifePath^® Dynamic 2030 Fund, BlackRock LifePath^® Dynamic 2040 Fund, BlackRock LifePath^® Dynamic 2050 Fund and BlackRock LifePath^® Dynamic 2060 Fund (five of the series constituting BlackRock Funds III, hereafter collectively referred to as the “Funds”) as of December 31, 2019, the related statements of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the periods indicated therein (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Funds as of December 31, 2019, the results of each of their operations for the year then ended, the changes in each of their net assets for each of the two years in the period ended December 31, 2019 and each of the financial highlights for each of the periods indicated therein in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinions

These financial statements are the responsibility of the Funds’ management. Our responsibility is to express an opinion on the Funds’ financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Funds in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolios. We believe that our audits provide a reasonable basis for our opinions.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

Important Tax Information  (unaudited)

The following information is provided with respect to the ordinary income distributions paid during the tax year ended December 31, 2018.

	Payable Dates	LifePath Dynamic Retirement Fund			LifePath Dynamic 2020 Fund (a)			LifePath Dynamic 2030 Fund			LifePath Dynamic 2040 Fund			LifePath Dynamic 2050 Fund			LifePath Dynamic 2060 Fund
Qualified Dividend Income for Individuals(b)	Quarterly		26.84	%		19.06	%		40.00	%		58.13	%		85.77	%		78.10	%
Qualified Business Income(b)			0.16			0.48			3.55			6.75			10.59			7.53
Dividends Qualifying for the Dividend Received Deduction for Corporations(b)	Quarterly		8.56			7.15			12.61			17.49			24.62			21.31
Federal Obligation Interest(c)	Quarterly		6.65			5.27			4.53			3.60			3.23			2.36
Interest Related Dividends and Short-Term Capital Gains forNon-U.S. Residents(d)	Quarterly		58.88			72.04			50.29			29.91			12.17			6.50

^(a)  Effective November 18, 2019, LifePath^® Dynamic 2020 Fund reorganized into LifePath Dynamic Retirement Fund.

^(b)  The LifePath Dynamic Funds hereby designate the percentages indicated above or the maximum amount allowable by law.

^(c)  The law varies in each state as to whether and what percentage of dividend income attributable to federal obligations is exempt from state income tax. We recommend that you consult your tax advisor to determine if any portion of the dividends you received is exempt from state income taxes.

^(d)  Represents the portion of the taxable ordinary income dividends eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations.

Additionally, the LifePath Dynamic Funds distributed long-term capital gains per share to shareholders of record as follows:

	Record Dates	LifePath Dynamic Retirement Fund		LifePath Dynamic 2020 Fund (a)		LifePath Dynamic 2030 Fund		LifePath Dynamic 2040 Fund		LifePath Dynamic 2050 Fund		LifePath Dynamic 2060 Fund
Long-Term Capital Gains Per Share	11/12/2019	$	—	$	0.4764330	$	—	$	—	$	—	$	—
	12/30/2019		0.070219		—		0.446555		0.693051		0.806609		0.118900

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM / IMPORTANT TAX INFORMATION 57

Master Portfolio Information  as of December 31, 2019

LifePath^® Dynamic Retirement Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Fixed Income Funds		55	%
Equity Funds		37
Short-Term Securities		9
Liabilities in Excess of Other Assets		(1	)

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
CoreAlpha Bond Master Portfolio		39	%
Active Stock Master Portfolio		22
iShares TIPS Bond ETF		8
Master Total Return Portfolio		8
International Tilts Master Portfolio		5
BlackRock Advantage Emerging Markets Fund — Class K		3
BlackRock Tactical Opportunities Fund — Class K		3
iShares Developed Real Estate Index Fund — Class K		2
iShares MSCI EAFESmall-Cap ETF		1

LifePath^® Dynamic 2030 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		61	%
Fixed Income Funds		31
Short-Term Securities		8

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		36	%
CoreAlpha Bond Master Portfolio		21
International Master Portfolio		11
BlackRock Advantage Emerging Markets Fund — Class K		6
iShares TIPS Bond ETF		6
Master Total Return Portfolio		4
iShares Developed Real Estate Index Fund — Class K		3
BlackRock Tactical Opportunities Fund — Class K		3
iShares MSCI EAFESmall-Cap ETF		3

LifePath^® Dynamic 2040 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		82	%
Fixed Income Funds		11
Short-Term Securities		8
Liabilities in Excess of Other Assets		(1	)

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		47	%
International Tilts Master Portfolio		15
BlackRock Advantage Emerging Markets Fund — Class K		9
CoreAlpha Bond Master Portfolio		7
iShares Developed Real Estate Index Fund — Class K		4
iShares MSCI EAFESmall-Cap ETF		4
iShares TIPS Bond ETF		3
BlackRock Tactical Opportunities Fund — Class K		3
Master Total Return Portfolio		1

The LifePath Dynamic Master Portfolios’ allocations and holdings listed above are current as of the report date. However, the LifePath Dynamic Master Portfolios are regularly monitored and their composition may vary throughout various periods.

58 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Master Portfolio Information  as of December 31, 2019 (continued)

LifePath^® Dynamic 2050 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		89	%
Short-Term Securities		12
Fixed Income Funds		1
Liabilities in Excess of Other Assets		(2	)

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		52	%
International Tilts Master Portfolio		18
BlackRock Advantage Emerging Markets Fund — Class K		10
iShares Developed Real Estate Index Fund — Class K		5
iShares MSCI EAFESmall-Cap ETF		4
CoreAlpha Bond Master Portfolio		1

LifePath^® Dynamic 2060 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		94	%
Short-Term Securities		5
Fixed Income Funds		1

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		52	%
International Tilts Master Portfolio		19
BlackRock Advantage Emerging Markets Fund — Class K		10
iShares Developed Real Estate Index Fund — Class K		5
iShares MSCI EAFESmall-Cap ETF		4
iShares MSCI Canada ETF		3
iShares Russell 2000 ETF		2
CoreAlpha Bond Master Portfolio		1

The LifePath Dynamic Master Portfolios’ allocations and holdings listed above are current as of the report date. However, the LifePath Dynamic Master Portfolios are regularly monitored and their composition may vary throughout various periods.

MASTER PORTFOLIO INFORMATION 59

Schedule of Investments December 31, 2019 LifePath Dynamic Retirement Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d) — 100.9%
Equity Funds — 36.9%
Active Stock Master Portfolio	$	90,865,442	$	90,865,442
BlackRock Advantage Emerging Markets Fund — Class K		1,182,456		12,900,594
BlackRock Tactical Opportunities Fund — Class K		921,851		12,380,456
International Tilts Master Portfolio	$	20,140,491		20,140,491
iShares Developed Real Estate Index Fund — Class K		828,024		9,091,707
iShares MSCI EAFESmall-Cap ETF(a)		83,346		5,190,789
				150,569,479
Fixed Income Funds — 55.2%
CoreAlpha Bond Master Portfolio	$	160,689,142		160,689,142
iShares TIPS Bond ETF		281,657		32,832,756
Master Total Return Portfolio	$	31,906,371		31,906,371
				225,428,269

Security	Shares		Value
Short-Term Securities — 8.8%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(b)(c)		252,847	$	252,948
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(c)		35,793,498		35,793,498
				36,046,446
Total Affiliated Investment Companies — 100.9% (Cost — $318,350,676)				412,044,194
Liabilities in Excess of Other Assets — (0.9)%				(3,522,634	)
Net Assets — 100.0%			$	408,521,560

^(a)  Security, or a portion of the security, is on loan.

^(b)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(c)  Annualized7-day yield as of period end.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties		Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased			Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss)	(a)		Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio	$	26,264,955	$	64,600,487	(b)	$	—		$	90,865,442	$	90,865,442	$	658,366		$	4,370,424		$	6,855,495
BlackRock Advantage Emerging Markets Fund — Class K		392,861		1,011,259			(221,664	)		1,182,456		12,900,594		287,315			(113,099	)		1,075,150
BlackRock Cash Funds: Institutional, SL Agency Shares		1,293,646		—			(1,040,799	)(b)		252,847		252,948		5,929	(c)		187			1
BlackRock Cash Funds: Treasury, SL Agency Shares		3,984,522		31,808,976	(b)		—			35,793,498		35,793,498		187,537			—			—
BlackRock Tactical Opportunities Fund — Class K		259,496		695,228			(32,873	)		921,851		12,380,456		408,216			8,319			(364,738	)
CoreAlpha Bond Master Portfolio	$	44,525,554	$	116,163,588	(b)	$	—		$	160,689,142		160,689,142		1,842,961			750,998			783,614
International Tilts Master Portfolio	$	7,798,563	$	12,341,928	(b)	$	—		$	20,140,491		20,140,491		259,796			476,903			2,492,794
iShares Developed Real Estate Index Fund — Class K		—		831,759			(3,735	)		828,024		9,091,707		354,026			(336	)		(212,801	)
iShares Edge MSCI Multifactor International ETF(d)		46,405		13,064			(59,469	)		—		—		24,168			74,826			38,627
iShares Edge MSCI Multifactor USA ETF(d)		15,620		30,123			(45,743	)		—		—		11,969			117,024			(11,444	)
iShares International Developed Real Estate ETF(d)		—		18,763			(18,763	)		—		—		3,786			(3,550	)		—
iShares MSCI EAFESmall-Cap ETF		24,473		63,927			(5,054	)		83,346		5,190,789		127,249			(25,564	)		423,293
iShares TIPS Bond ETF		85,948		215,274			(19,565	)		281,657		32,832,756		215,490			64,182			690,321
iShares U.S. Real Estate ETF(d)		—		9,011			(9,011	)		—		—		—			(809	)		—
Master Total Return Portfolio	$	6,685,677	$	25,220,694	(b)	$	—		$	31,906,371		31,906,371		465,200			187,677			(1,188,220	)
												$412,044,194	$	4,852,008		$	5,907,182		$	10,582,092

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/investment value purchased (sold).

^(c)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

60 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic Retirement Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		23		03/19/20	$	3,586	$	17,195
10-Year U.S. Treasury Note		38		03/20/20		4,880		(42,313	)
E-Mini MSCI EAFE Index		92		03/20/20		9,368		249,479
Russell 2000E-Mini Index		166		03/20/20		13,866		285,249
S&P 500E-Mini Index		19		03/20/20		3,070		87,756
								597,366
Short Contracts
U.S. Treasury Ultra Bond		23		03/20/20		4,178		134,368
							$	731,734

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	3,836,636	USD	2,894,357	Morgan Stanley & Co. International PLC		03/18/20	$	60,986
EUR	19,614,880	USD	21,861,568	Bank of America N.A.		03/18/20		243,778
	Net unrealized appreciation						$	304,764

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instrument
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	639,679	$	—	$	134,368	$	—	$	774,047
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		304,764		—		—		304,764
	$	—	$	—	$	639,679	$	304,764	$	134,368	$	—	$	1,078,811
Liabilities — Derivative Financial Instrument
Futures contracts
Unrealized depreciation on futures contracts(a)	$	—	$	—	$	—	$	—	$	42,313	$	—	$	42,313

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	1,656,921	$	—		$	36,475	$	—	$	1,693,396
Forward foreign currency exchange contracts		—		—		—		(436,137	)		—		—		(436,137	)
	$	—	$	—	$	1,656,921	$	(436,137	)	$	36,475	$	—	$	1,257,259
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	1,135,662	$	—		$	26,480	$	—	$	1,162,142
Forward foreign currency exchange contracts		—		—		—		401,980			—		—		401,980
	$	—	$	—	$	1,135,662	$	401,980		$	26,480	$	—	$	1,564,122

SCHEDULES OF INVESTMENTS 61

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic Retirement Master Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	17,499,138
Average notional value of contracts — short	$	3,538,125
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	2,021,639
Average amounts sold — USD	$	14,145,827

For more information about the LifePath Dynamic Master Portfolio’s Investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	99,089		$	10,181
Forward foreign currency exchange contracts		304,764			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	403,853		$	10,181
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(99,089	)		(10,181	)
Total derivative assets and liabilities subject to an MNA	$	304,764		$	—

The following table presents the LifePath Dynamic Master Portfolio‘s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)(b)
Bank of America N.A.	$	243,778	$	—	$	—	$	—	$	243,778
Morgan Stanley & Co. International PLC		60,986		—		—		—		60,986
	$	304,764	$	—	$	—	$	—	$	304,764

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1			Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investment Companies
Equity Funds	$	39,563,546		$	—	$	—	$	39,563,546
Fixed Income Funds		32,832,756			—		—		32,832,756
Short-Term Securities		36,046,446			—		—		36,046,446
Subtotal	$	108,442,748		$	—	$	—	$	108,442,748
Investments Valued at NAV(a)									303,601,446
Total Investments								$	412,044,194
Derivative Financial Instruments(b)
Assets:
Equity contracts	$	639,679		$	—	$	—	$	639,679
Forward foreign currency contracts		—			304,764		—		304,764
Interest rate contracts		134,368			—		—		134,368
Liabilities:
Interest rate contracts		(42,313	)		—		—		(42,313	)
	$	731,734		$	304,764	$		$	1,036,498

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

62 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 LifePath Dynamic 2030 Master Portfolio (Percentages shown are based on Net Assets)

Security	Investment Value		Value
Affiliated Investment Companies(d) — 99.9%
Equity Funds — 61.4%
Active Stock Master Portfolio	$	125,478,627	$	125,478,627
BlackRock Advantage Emerging Markets Fund — Class K		2,044,794		22,308,701
BlackRock Tactical Opportunities Fund — Class K		788,141		10,584,730
International Tilts Master Portfolio	$	37,353,587		37,353,587
iShares Developed Real Estate Index Fund — Class K		990,451		10,875,154
iShares MSCI EAFESmall-Cap ETF(a)		144,419		8,994,415
				215,595,214
Fixed Income Funds — 30.8%
CoreAlpha Bond Master Portfolio	$	72,562,515		72,562,515
iShares TIPS Bond ETF(a)		184,763		21,537,823
Master Total Return Portfolio	$	13,956,441		13,956,441
				108,056,779

Security	Investment Value		Value
Short-Term Securities — 7.7%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(b)(c)	$	1,083,754	$	1,084,188
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(b)		25,813,659		25,813,659
				26,897,847
Total Affiliated Investment Companies — 99.9% (Cost — $320,913,529)				350,549,840
Other Assets Less Liabilities — 0.1%				291,762
Net Assets — 100.0%			$	350,841,602

^(a)  Security, or a portion of the security, is on loan.

^(b)  Annualized7-day yield as of period end.

^(c)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties		Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased			Shares/ Investment Value Sold			Shares/ Investment Value at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss)	(a)		Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio	$	116,921,680	$	8,556,947	(b)	$	—		$	125,478,627	$	125,478,627	$	2,247,992		$	12,642,750		$	18,986,434
BlackRock Advantage Emerging Markets Fund — Class K		1,841,392		694,056			(490,654	)		2,044,794		22,308,701		505,151			(249,507	)		3,160,089
BlackRock Cash Funds: Institutional, SL Agency Shares		7,025,957		—			(5,942,203	)(b)		1,083,754		1,084,188		19,704	(c)		4,859			—
BlackRock Cash Funds: Treasury, SL Agency Shares		927,237		24,886,422	(b)		—			25,813,659		25,813,659		259,146			—			—
BlackRock Tactical Opportunities Fund — Class K		745,753		103,602			(61,214	)		788,141		10,584,730		343,416			13,639			(158,906	)
CoreAlpha Bond Master Portfolio	$	64,489,702	$	8,072,813	(b)	$	—		$	72,562,515		72,562,515		2,036,075			1,839,600			(1,012,625	)
International Tilts Master Portfolio	$	33,994,754	$	3,358,833	(b)	$	—		$	37,353,587		37,353,587		1,165,977			1,078,449			10,458,745
iShares Developed Real Estate Index Fund — Class K		—		1,366,863			(376,412	)		990,451		10,875,154		470,267			(5,178	)		(232,953	)
iShares Edge MSCI Multifactor International ETF		278,178		—			(278,178	)		—		—		113,832			734,761			(168,724	)
iShares Edge MSCI Multifactor USA ETF		142,679		16,341			(159,020	)		—		—		49,273			587,137			(29,917	)
iShares MSCI EAFESmall-Cap ETF		132,778		16,613			(4,972	)		144,419		8,994,415		305,391			(21,169	)		1,471,194
iShares TIPS Bond ETF		120,087		85,090			(20,414	)		184,763		21,537,823		314,731			22,479			941,233
Master Total Return Portfolio	$	10,741,999	$	3,214,442	(b)	$	—		$	13,956,441		13,956,441		474,074			284,526			(793,502	)
											$	350,549,840	$	8,305,029		$	16,932,346		$	32,621,068

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/ investment value purchased (sold).

^(c)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

SCHEDULES OF INVESTMENTS 63

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2030 Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		39		03/19/20	$	6,081	$	29,156
E-Mini MSCI EAFE Index		126		03/20/20		12,830		341,678
Russell 2000E-Mini Index		116		03/20/20		9,689		199,330
S&P 500E-Mini Index		17		03/20/20		2,746		78,519
								648,683
Short Contracts
10-Year U.S. Treasury Note		32		03/20/20		4,110		35,956
U.S. Treasury Ultra Bond		20		03/20/20		3,633		116,842
								152,798
							$	801,481

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	7,030,413	USD	5,303,789	Morgan Stanley & Co. International PLC		03/18/20	$	111,706
EUR	631,000	USD	703,989	Bank of America N.A.		03/18/20		7,128
EUR	16,185,713	USD	18,038,977	Deutsche Bank AG		03/18/20		201,807
	Net unrealized appreciation						$	320,641

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instrument
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	648,683	$	—		$	152,798	$	—	$	801,481
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		320,641			—		—		320,641
	$	—	$	—	$	648,683	$	320,641		$	152,798	$	—	$	1,122,122
									��

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts			Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	3,425,587	$	—		$	487,881		$	—	$	3,913,468
Forward foreign currency exchange contracts		—		—		—		(1,093,641	)		—			—		(1,093,641	)
	$	—	$	—	$	3,425,587	$	(1,093,641	)	$	487,881		$	—	$	2,819,827
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	1,692,277	$	—		$	(26,820	)	$	—	$	1,665,457
Forward foreign currency exchange contracts		—		—				658,514			—			—		658,514
	$	—	$	—	$	1,692,277	$	658,514		$	(26,820	)	$	—	$	2,323,971

64 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2030 Master Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	35,246,607
Average notional value of contracts — short	$	9,996,844
Forward foreign currency exchange contracts:
Average USD amounts purchased	$	8,074,860
Average USD amounts sold	$	30,442,292

For more information about the LifePath Dynamic Master Portfolio’s Investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	110,190		$	10,211
Forward foreign currency exchange contracts		320,641			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	430,831		$	10,211
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(110,190	)		(10,211	)
Total derivative assets and liabilities subject to an MNA	$	320,641		$	—

The following table presents the LifePath Dynamic Master Portfolio‘s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty		Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets	(a)(b)
Bank of America N.A.	$	7,128	$	—	$	—	$	—	$	7,128
Deutsche Bank AG		201,807		—		—		—		201,807
Morgan Stanley & Co. International PLC		111,706		—		—		—		111,706
	$	320,641	$	—	$	—	$	—	$	320,641

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investments Companies
Equity Funds	$	52,763,000	$	—	$	—	$	52,763,000
Fixed Income Funds		21,537,823		—		—		21,537,823
Short-Term Securities		26,897,847		—		—		26,897,847
Subtotal	$	101,198,670	$	—	$	—	$	101,198,670
Investments Valued at NAV(a)								249,351,170
Total Investments							$	350,549,840
Derivative Financial Instruments(b)
Assets:
Equity contracts	$	648,683	$	—	$	—	$	648,683
Forward foreign currency contracts		—		320,641		—		320,641
Interest rate contracts		152,798		—		—		152,798
	$	801,481	$	320,641	$	—	$	1,122,122

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore and have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

SCHEDULES OF INVESTMENTS 65

Schedule of Investments December 31, 2019 LifePath Dynamic 2040 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d) — 100.8%
Equity Funds — 81.9%
Active Stock Master Portfolio	$	136,236,751	$	136,236,751
BlackRock Advantage Emerging Markets Fund — Class K		2,388,194		26,055,202
BlackRock Tactical Opportunities Fund — Class K		652,282		8,760,150
International Tilts Master Portfolio	$	43,485,982		43,485,982
iShares Developed Real Estate Index Fund — Class K		1,110,007		12,187,882
iShares MSCI EAFESmall-Cap ETF(a)		166,112		10,345,455
				237,071,422
Fixed Income Funds — 10.9%
CoreAlpha Bond Master Portfolio	$	18,948,856		18,948,856
iShares TIPS Bond ETF		76,765		8,948,496
Master Total Return Portfolio	$	3,560,921		3,560,921
				31,458,273

Security	Shares		Value
Short-Term Securities — 8.0%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(b)(c)		3,670,132	$	3,671,600
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(c)		19,567,093		19,567,093
				23,238,693
Total Affiliated Investment Companies — 100.8% (Cost — $248,170,295)				291,768,388
Liabilities in Excess of Other Assets — (0.8)%				(2,278,385	)
Net Assets — 100.0%			$	289,490,003

^(a)  Security, or a portion of the security, is on loan.

^(b)  Security was purchased with the cash collateral from loaned securities.

^(c)  Annualized7-day yield as of period end.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased			Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio	$	113,277,653	$	22,959,098	(b)	$	—		$	136,236,751	$	136,236,751	$	2,245,908		$	11,752,906		$	17,335,596
BlackRock Advantage Emerging Markets Fund — Class K		1,896,578		864,439			(372,823	)		2,388,194		26,055,202		585,782			(230,840	)		3,304,943
BlackRock Cash Funds: Institutional, SL Agency Shares		8,282,344		—			(4,612,212	)(b)		3,670,132		3,671,600		20,633	(c)		3,500			—
BlackRock Cash Funds: Treasury, SL Agency Shares		4,091,592		15,475,501	(b)		—			19,567,093		19,567,093		231,344			—			—
BlackRock Tactical Opportunities Fund — Class K		607,477		102,176			(57,371	)		652,282		8,760,150		283,911			10,495			(133,172	)
CoreAlpha Bond Master Portfolio	$	16,279,448	$	2,669,408	(b)	$	—		$	18,948,856		18,948,856		512,303			504,094			(808,319	)
International Tilts Master Portfolio	$	34,811,321	$	8,674,661	(b)	$	—		$	43,485,982		43,485,982		1,240,879			1,113,602			9,928,925
iShares Developed Real Estate Index Fund — Class K		—		1,719,542			(609,535	)		1,110,007		12,187,882		527,310			(7,989	)		(255,271	)
iShares Edge MSCI Multifactor International ETF(d)		287,336		—			(287,336	)		—		—		117,002			748,905			(187,855	)
iShares Edge MSCI Multifactor USA ETF(d)		242,674		7,861			(250,535	)		—		—		71,763			1,402,501			(396,162	)
iShares MSCI EAFESmall-Cap ETF		141,321		32,904			(8,113	)		166,112		10,345,455		340,639			(34,777	)		1,642,926
iShares TIPS Bond ETF		32,193		51,569			(6,997	)		76,765		8,948,496		111,572			9,903			279,136
Master Total Return Portfolio	$	2,502,333	$	1,058,588	(b)	$	—		$	3,560,921		3,560,921		132,128			87,212			17,994
											$	291,768, 388	$	6,421,174		$	15,359,512		$	30,728,741

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net of shares/investment value purchased (sold).

^(c)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

66 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2040 Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		53		03/19/20	$	8,264	$	39,623
E-Mini MSCI EAFE Index		137		03/20/20		13,950		352,487
Russell 2000E-Mini Index		77		03/20/20		6,432		132,314
S&P 500E-Mini Index		14		03/20/20		2,262		64,662
								589,086
Short Contracts
10-Year U.S. Treasury Note		66		03/20/20		8,476		72,279
U.S. Treasury Ultra Bond		16		03/20/20		2,907		93,473
								165,752
							$	754,838

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	8,015,278	USD	6,046,724	Morgan Stanley & Co. International PLC		03/18/20	$	127,409
EUR	224,589	USD	250,313	Bank of America N.A.		03/18/20		2,791
EUR	770,000	USD	859,067	Bank of America N.A.		03/18/20		8,698
EUR	12,885,730	USD	14,360,760	Bank of America N.A.		03/18/20		161,049
	Net unrealized appreciation						$	299,947

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	589,086	$	—	$	165,752	$	—	$	754,838
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		299,947		—		—		299,947
	$	—	$	—	$	589,086	$	299,947	$	165,752	$	—	$	1,054,785

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts			Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	3,100,333	$	—		$	370,686		$	—	$	3,471,019
Forward foreign currency exchange contracts		—		—		—		(911,714	)		—			—		(911,714	)
	$	—	$	—	$	3,100,333	$	(911,714	)	$	370,686		$	—	$	2,559,305
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	1,415,759	$	—		$	(2,462	)	$	—	$	1,413,297
Forward foreign currency exchange contracts		—		—		—		604,664			—			—		604,664
	$	—	$	—	$	1,415,759	$	604,664		$	(2,462	)	$	—	$	2,017,961

SCHEDULES OF INVESTMENTS 67

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2040 Master Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	33,750,027
Average notional value of contracts — short	$	11,741,188
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	9,034,346
Average amounts sold — in USD	$	27,861,476

For more information about the LifePath Dynamic Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	105,841		$	13,834
Forward foreign currency exchange contracts		299,947			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	405,788		$	13,834
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(105,841	)		(13,834	)
Total derivative assets and liabilities subject to an MNA	$	299,947		$	—

The following table presents the LifePath Dynamic Master Portfolio’s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)(b)
Bank of America N.A.	$	172,538	$	—	$	—	$	—	$	172,538
Morgan Stanley & Co. International PLC		127,409		—		—		—		127,409
	$	299,947	$	—	$	—	$	—	$	299,947

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investment Companies
Equity Funds	$	57,348,689	$	—	$	—	$	57,348,689
Fixed Income Funds		8,948,496		—		—		8,948,496
Short-Term Securities		23,238,693		—		—		23,238,693
Subtotal	$	89,535,878	$	—	$	—	$	89,535,878
Investments Valued at NAV(a)								202,232,510
Total Investments							$	291,768,388
Derivative Financial Instruments(b)
Assets:
Forward foreign currency contracts	$	—	$	299,947	$	—	$	299,947
Interest rate contracts		165,752		—		—		165,752
Equity contracts		589,086		—		—		589,086
	$	754,838	$	299,947	$	—	$	1,054,785

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

68 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 LifePath Dynamic 2050 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d) — 102.3%
Equity Funds — 89.3%
Active Stock Master Portfolio	$	59,597,236	$	59,597,236
BlackRock Advantage Emerging Markets Fund — Class K		1,068,663		11,659,112
International Tilts Master Portfolio	$	20,296,393		20,296,393
iShares Developed Real Estate Index Fund — Class K		494,249		5,426,849
iShares MSCI EAFESmall-Cap ETF(a)		74,791		4,657,983
				101,637,573
Fixed Income Funds — 1.1%
CoreAlpha Bond Master Portfolio	$	882,431		882,431
iShares TIPS Bond ETF		3,279		382,233
Master Total Return Portfolio	$	10		133
				1,264,797

Security	Shares		Value
Short-Term Securities — 11.9%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(b)(c)		2,902,014	$	2,903,175
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(c)		10,682,760		10,682,760
				13,585,935
Total Affiliated Investment Companies — 102.3% (Cost — $90,671,865)				116,488,305
Liabilities in Excess of Other Assets — (2.3)%				(2,654,797	)
Net Assets — 100.0%			$	113,833,508

^(a)  Security, or a portion of the security, is on loan.

^(b)  Security was purchased with the cash collateral from loaned securities.

^(c)  Annualized7-day yield as of period end.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased			Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio	$	42,401,895	$	17,195,341	(b)	$	—		$	59,597,236	$	59,597,236	$	915,997		$	4,294,520		$	7,202,786
BlackRock Advantage Emerging Markets Fund — Class K		780,716		458,648			(170,701	)		1,068,663		11,659,112		260,485			(86,370	)		1,442,742
BlackRock Cash Funds: Institutional, SL Agency Shares		2,695,486		206,528	(b)		—			2,902,014		2,903,175		10,127	(c)		1,133			—
BlackRock Cash Funds: Treasury, SL Agency Shares		576,483		10,106,277	(b)		—			10,682,760		10,682,760		119,810			—			—
CoreAlpha Bond Master Portfolio	$	1,274,579	$	—		$	(392,148	)(b)	$	882,431		882,431		36,969			40,665			(79,699	)
International Tilts Master Portfolio	$	14,660,636	$	5,635,757	(b)	$	—		$	20,296,393		20,296,393		544,318			529,626			4,066,673
iShares Developed Real Estate Index Fund — Class K		—		767,477			(273,228	)		494,249		5,426,849		235,195			(540	)		(113,832	)
iShares Edge MSCI Multifactor International ETF(d)		122,251		1,146			(123,397	)		—		—		65,356			329,556			(98,647	)
iShares Edge MSCI Multifactor USA ETF(d)		127,245		374			(127,619	)		—		—		43,921			737,511			(214,998	)
iShares MSCI EAFESmall-Cap ETF		49,839		27,395			(2,443	)		74,791		4,657,983		148,813			(6,827	)		670,044
iShares TIPS Bond ETF		—		3,279			—			3,279		382,233		3,825			—			3,935
Master Total Return Portfolio	$	—	$	10	(b)	$	—		$	10		133		1			—			—
											$	116,488,305	$	2,384,817		$	5,839,274		$	12,879,004

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net of shares/investment value purchased (sold).

^(c)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

SCHEDULES OF INVESTMENTS 69

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2050 Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		20		03/19/20	$	3,119	$	14,952
10-Year U.S. Treasury Note		1		03/20/20		128		(1,054	)
E-Mini MSCI EAFE Index		58		03/20/20		5,906		146,412
Russell 2000E-Mini Index		27		03/20/20		2,255		46,396
							$	206,706

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	3,979,020	USD	3,001,799	Morgan Stanley & Co. International PLC		03/18/20	$	63,222
EUR	145,003	USD	161,601	Bank of America N.A.		03/18/20		1,812
EUR	350,000	USD	390,485	Bank of America N.A.		03/18/20		3,954
EUR	4,981,172	USD	5,551,715	Bank of America N.A.		03/18/20		61,907
	Net unrealized appreciation						$	130,895

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on future contracts(a)	$	—	$	—	$	207,760	$	—	$	—	$	—	$	207,760
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		130,895		—		—		130,895
	$	—	$	—	$	207,760	$	130,895	$	—	$	—	$	338,655
Liabilities — Derivative Financial Instruments
Futures contracts
Unrealized depreciation on future contracts(a)	$	—	$	—	$	—	$	—	$	1,054	$	—	$	1,054

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts			Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	681,542	$	—		$	(904	)	$	—	$	680,638
Forward foreign currency exchange contracts		—		—		—		(333,486	)		—			—		(333,486	)
	$	—	$	—	$	681,542	$	(333,486	)	$	(904	)	$	—	$	347,152
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	254,658	$	—		$	(1054	)	$	—	$	253,604
Forward foreign currency exchange contracts		—		—		—		247,280			—			—		247,280
	$	—	$	—	$	254,658	$	247,280		$	(1054	)	$	—	$	500,884

70 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2050 Master Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	8,623,154
Average notional value of contracts — short	$	106,418
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	3,646,349
Average amounts sold — in USD	$	11,052,887

For more information about the LifePath Dynamic Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	30,489		$	5,348
Forward foreign currency exchange contracts		130,895			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	161,384		$	5,348
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(30,489	)		(5,348	)
Total derivative assets and liabilities subject to an MNA	$	130,895		$	—

The following table presents the LifePath Dynamic Master Portfolio’s derivative assets by counterparty net of amounts available for offset under a MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets (a)(b)
Bank of America N.A.	$	67,673	$	—	$	—	$	—	$	67,673
Morgan Stanley & Co. International PLC		63,222		—		—		—		63,222
	$	130,895	$	—	$	—	$	—	$	130,895

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1			Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investment Companies
Equity Funds	$	21,743,944		$	—	$	—	$	21,743,944
Fixed Income Funds		382,233			—		—		382,233
Short-Term Securities		13,585,935			—		—		13,585,935
Subtotal	$	35,712,112		$	—	$	—	$	35,712,112
Investments Valued at NAV(a)									80,776,193
Total Investments								$	116,488,305
Derivative Financial Instruments(b)
Assets:
Forward foreign currency contracts	$	—		$	130,895	$	—	$	130,895
Interest rate contracts		207,760			—		—		207,760
Liabilities:
Interest rate contracts		(1,054	)		—		—		(1,054	)
	$	206,706		$	130,895	$	—	$	337,601

^(a) Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

SCHEDULES OF INVESTMENTS 71

Schedule of Investments December 31, 2019 LifePath Dynamic 2060 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(b) — 99.8%
Equity Funds — 94.0%
Active Stock Master Portfolio	$	2,237,253	$	2,237,253
BlackRock Advantage Emerging Markets Fund — Class K		40,417		440,954
International Tilts Master Portfolio	$	797,387		797,387
iShares Developed Real Estate Index Fund — Class K		17,965		197,252
iShares MSCI Canada ETF		3,747		111,998
iShares MSCI EAFESmall-Cap ETF		2,705		168,467
iShares Russell 2000 ETF		514		85,154
				4,038,465
Fixed Income Funds — 0.9%
CoreAlpha Bond Master Portfolio	$	37,326		37,326
iShares TIPS Bond ETF		26		3,031
Master Total Return Portfolio	$	10		133
				40,490

Security	Shares		Value
Short-Term Securities — 4.9%
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(a)		211,018	$	211,018
Total Affiliated Investment Companies — 99.8% (Cost — $3,903,909)				4,289,973
Other Assets Less Liabilities — 0.2%				8,519
Net Assets — 100.0%			$	4,298,492

^(a)  Annualized7-day yield as of period end.

^(b)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Lifepath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the Lifepath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased			Shares/ Investment Value Sold			Shares/ Investment Value at 12/31/19		Value at 12/31/19		Income		Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio	$	953,734	$	1,283,519	(b)	$	—		$	2,237,253	$	2,237,253	$	23,528	$	93,189		$	231,572
BlackRock Advantage Emerging Markets Fund — Class K		18,738		24,242			(2,563	)		40,417		440,954		7,504		(1,399	)		43,954
BlackRock Cash Funds: Treasury, SL Agency Shares		21,770		189,248	(b)		—			211,018		211,018		1,916		—			—
CoreAlpha Bond Master Portfolio	$	24,059	$	13,267	(b)	$	—		$	37,326		37,326		823		540			462
International Tilts Master Portfolio	$	362,496	$	434,891	(b)	$	—		$	797,387		797,387		13,962		13,223			102,756
iShares Developed Real Estate Index Fund — Class K		—		23,551			(5,586	)		17,965		197,252		8,300		(56	)		(4,652	)
iShares Edge MSCI Multifactor International ETF(c)		2,725		224			(2,949	)		—		—		1,431		(3,016	)		8,076
iShares Edge MSCI Multifactor USA ETF(c)		3,935		190			(4,125	)		—		—		1,314		10,900			3,892
iShares International Developed Real Estate ETF(c)		—		1,580			(1,580	)		—		—		326		(412	)		—
iShares MSCI Canada ETF		1,571		2,388			(212	)		3,747		111,998		1,820		(829	)		11,371
iShares MSCI EAFESmall-Cap ETF		1,115		1,649			(59	)		2,705		168,467		4,680		(799	)		20,025
iShares Russell 2000 ETF		266		352			(104	)		514		85,154		796		(806	)		12,034
iShares TIPS Bond ETF		—		26			—			26		3,031		10		—			11
iShares U.S. Real Estate ETF		—		750			(750	)		—		—		—		(67	)		—
Master Total Return Portfolio	$	—	$	10	(b)	$	—		$	10		133		1		—			—
											$	4,289,973	$	66,411	$	110,468		$	429,501

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/ investment value purchased (sold).

^(c)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
E-Mini MSCI EAFE Index		2		03/20/20	$	204	$	5,423

72 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2060 Master Portfolio

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	2,304	USD	1,738	Morgan Stanley & Co. International PLC		03/18/20	$	37
EUR	168,461	USD	187,757	Bank of America N.A.		03/18/20		2,094
EUR	27,125	USD	30,231	Deutsche Bank AG		03/18/20		338
EUR	10,000	USD	11,157	Standard Chartered Bank		03/18/20		113
	Net unrealized appreciation						$	2,582

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instrument
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	5,423	$	—	$	—	$	—	$	5,423
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		2,582		—		—		2,582
	$	—	$	—	$	5,423	$	2,582	$	—	$	—	$	8,005

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	6,390	$	—		$	—	$	—	$	6,390
Forward foreign currency exchange contracts		—		—		—		(8,706	)		—		—		(8,706	)
	$	—	$	—	$	6,390	$	(8,706	)	$	—	$	—	$	(2,316	)
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	5,423	$	—		$	—	$	—	$	5,423
Forward foreign currency exchange contracts		—		—				5,129			—		—		5,129
	$	—	$	—	$	5,423	$	5,129		$	—	$	—	$	10,552

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts long	$	122,725
Forward foreign currency exchange contracts:
Average USD amounts purchased	$	83,091
Average USD amounts sold	$	240,598

For more information about the LifePath Dynamic Master Portfolio’s Investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements

SCHEDULES OF INVESTMENTS 73

Schedule of Investments  (continued) December 31, 2019 LifePath Dynamic 2060 Master Portfolio

Derivative Financial Instruments — Offsetting as of Period End

The LifePath Dynamic Master Portfolio’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	1,020		$	—
Forward foreign currency exchange contracts		2,582			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	3,602		$	—
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(1,020	)		—
Total derivative assets and liabilities subject to an MNA	$	2,582		$	—

The following table presents the Fund’s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)(b)
Bank of America N.A.	$	2,094	$	—	$	—	$	—	$	2,094
Deutsche Bank AG		338		—		—		—		338
Morgan Stanley & Co. International PLC		37		—		—		—		37
Standard Chartered Bank		113		—		—		—		113
	$	2,582	$	—	$	—	$	—	$	2,582

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investments Companies
Equity Funds	$	1,003,825	$	—	$	—	$	1,003,825
Fixed Income Funds		3,031		—		—		3,031
Short-Term Securities		211,018		—		—		211,018
Subtotal	$	1,217,874	$	—	$	—	$	1,217,874
Investments Valued at NAV(a)								3,072,099
Total Investments							$	4,289,973
Derivative Financial Instruments(b)
Assets:
Forward foreign currency contracts	$	—	$	2,582	$	—	$	2,582
Equity contracts		5,423		—		—		5,423
	$	5,423	$	2,582	$	—	$	8,005

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

74 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Assets and Liabilities

December 31, 2019

	LifePath Dynamic Retirement Master Portfolio		LifePath Dynamic 2030 Master Portfolio		LifePath Dynamic 2040 Master Portfolio		LifePath Dynamic 2050 Master Portfolio		LifePath Dynamic 2060 Master Portfolio
ASSETS
Investments at value — affiliated(a)(b)	$	412,044,194	$	350,549,840	$	291,768,388	$	116,488,305	$	4,289,973
Cash		—		—		—		—		1,754
Cash pledged for futures contracts		1,242,000		1,375,000		1,357,000		441,000		10,000
Foreign currency at value(c)		674,431		846,310		845,078		325,765		94
Receivables:
Investments sold		2,918,608		4,496,042		1,890,666		537,611		24,036
Securities lending income — affiliated		869		1,008		1,663		1,095		—
Contributions from investors		—		—		—		—		3,820
Dividends — affiliated		49,579		32,699		24,933		13,083		283
Variation margin on futures contracts		99,089		110,190		105,841		30,489		1,020
Unrealized appreciation on forward foreign currency exchange contracts		304,764		320,641		299,947		130,895		2,582
Prepaid expenses		—		—		—		—		4,014
Total assets		417,333,534		357,731,730		296,293,516		117,968,243		4,337,576
LIABILITIES
Cash collateral on securities loaned at value		253,000		1,084,850		3,671,599		2,903,175		—
Payables:
Investments purchased		4,912,948		4,053,469		1,319,883		251,620		21,372
Investment advisory fees		23,809		21,286		17,119		3,900		308
Trustees’ fees		4,674		3,301		3,061		2,476		2,101
Professional fees		29,176		15,898		15,865		15,491		15,303
Variation margin on futures contracts		10,181		10,211		13,834		5,348		—
Withdrawals to investors		3,578,186		1,701,113		1,762,152		952,725		—
Total liabilities		8,811,974		6,890,128		6,803,513		4,134,735		39,084
NET ASSETS	$	408,521,560	$	350,841,602	$	289,490,003	$	113,833,508	$	4,298,492
NET ASSETS CONSIST OF
Investors’ capital	$	314,828,042	$	320,067,772	$	244,821,745	$	87,673,683	$	3,904,410
Net unrealized appreciation		93,693,518		30,773,830		44,668,258		26,159,825		394,082
NET ASSETS	$	408,521,560	$	350,841,602	$	289,490,003	$	113,833,508	$	4,298,492
(a) Investments at cost — affiliated	$	318,350,676	$	320,913,529	$	248,170,295	$	90,671,865	$	3,903,909
(b) Securities loaned at value	$	249,120	$	1,061,914	$	3,615,291	$	2,858,652	$	—
(c) Foreign currency at cost	$	660,842	$	831,765	$	830,836	$	320,500	$	93

See notes to financial statements.

FINANCIAL STATEMENTS 75

Statements of Operations

Year Ended December 31, 2019

	LifePath Dynamic Retirement Master Portfolio			LifePath Dynamic 2030 Master Portfolio			LifePath Dynamic 2040 Master Portfolio			LifePath Dynamic 2050 Master Portfolio			LifePath Dynamic 2060 Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	1,619,756		$	2,361,207		$	2,269,323		$	877,405		$	28,097
Dividends — unaffiliated		5,185			302,704			394,168			165,499			5,933
Securities lending income — affiliated — net		5,929			19,704			20,633			10,127			—
Foreign taxes withheld		(1,619	)		(26,447	)		(36,783	)		(15,514	)		(416	)
Net investment income allocated from the applicable Underlying Master Portfolios:
Interest — affiliated		2,492,423			2,942,573			1,001,277			174,709			4,357
Dividends — affiliated		977,447			3,504,011			3,545,188			1,484,465			38,207
Expenses		(350,361	)		(841,088	)		(713,407	)		(282,324	)		(7,371	)
Fees waived		106,814			318,622			298,160			120,435			3,121
Total investment income		4,855,574			8,581,286			6,778,559			2,534,802			71,928
EXPENSES
Investment advisory		553,328			1,168,697			953,787			363,240			9,553
Professional		15,584			16,174			16,001			15,577			15,305
Trustees		12,545			15,627			14,688			12,186			10,726
Total expenses		581,457			1,200,498			984,476			391,003			35,584
Less fees waived and/or reimbursed by the Manager		(509,041	)		(1,042,766	)		(856,273	)		(343,308	)		(34,286	)
Total expenses after fees waived and/or reimbursed		72,416			157,732			128,203			47,695			1,298
Net investment income		4,783,158			8,423,554			6,650,356			2,487,107			70,630
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Allocation from the applicable Underlying Master Portfolios from investments, futures, forward foreign currency exchange contracts and foreign currency transactions		5,786,002			15,845,325			13,457,814			4,864,811			106,952
Futures contracts		1,693,396			3,913,468			3,471,019			680,638			6,390
Forward foreign currency exchange contracts		(436,137	)		(1,093,641	)		(911,714	)		(333,486	)		(8,706	)
Foreign currency transactions		6,361			29,793			3,897			(3,925	)		(231	)
Investments — unaffiliated		154,848			3,457,207			4,650,851			2,057,647			44,005
Investments — affiliated		121,180			1,087,021			1,901,698			974,463			3,516
Payment from affiliate(a)		—			—			—			—			2,603
		7,325,650			23,239,173			22,573,565			8,240,148			154,529
Net change in unrealized appreciation (depreciation) on:
Allocation from the applicable Underlying Master Portfolios from investments, futures, forward foreign currency exchange contracts and foreign currency transactions		8,943,683			27,639,052			26,474,196			11,189,760			334,790
Futures contracts		1,162,142			1,665,457			1,413,297			253,604			5,423
Forward foreign currency exchange contracts		401,980			658,514			604,664			247,280			5,129
Foreign currency translations		13,502			6,283			15,076			3,827			(32	)
Investments — unaffiliated		15,522			559,043			782,061			284,559			10,765
Investments — affiliated		1,638,409			4,982,016			4,254,545			1,689,244			94,711
		12,175,238			35,510,365			33,543,839			13,668,274			450,786
Net realized and unrealized gain		19,500,888			58,749,538			56,117,404			21,908,422			605,315
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	24,284,046		$	67,173,092		$	62,767,760		$	24,395,529		$	675,945

^(a)  Includes a payment by an affiliate of $2,603 to compensate for a trade operating event.

See notes to financial statements.

76 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	LifePath Dynamic Retirement Master Portfolio						LifePath Dynamic 2030 Master Portfolio
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	4,783,158		$	3,306,592		$	8,423,554		$	8,727,235
Net realized gain		7,325,650			3,307,624			23,239,173			19,220,681
Net change in unrealized appreciation (depreciation)		12,175,238			(9,881,188	)		35,510,365			(44,083,828	)
Net increase (decrease) in net assets resulting from operations		24,284,046			(3,266,972	)		67,173,092			(16,135,912	)
CAPITAL TRANSACTIONS
Proceeds from contributions		326,183,915			45,501,676			70,186,697			45,262,945
Value of withdrawals		(49,589,761	)		(73,015,545	)		(93,945,766	)		(118,606,130	)
Net increase (decrease) in net assets derived from capital transactions		276,594,154			(27,513,869	)		(23,759,069	)		(73,343,185	)
NET ASSETS
Total increase (decrease) in net assets		300,878,200			(30,780,841	)		43,414,023			(89,479,097	)
Beginning of year		107,643,360			138,424,201			307,427,579			396,906,676
End of year	$	408,521,560		$	107,643,360		$	350,841,602		$	307,427,579

See notes to financial statements.

FINANCIAL STATEMENTS 77

Statements of Changes in Net Assets  (continued)

	LifePath Dynamic 2040 Master Portfolio						LifePath Dynamic 2050 Master Portfolio
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	6,650,356		$	6,646,019		$	2,487,107		$	2,179,736
Net realized gain		22,573,565			17,885,406			8,240,148			6,553,196
Net change in unrealized appreciation (depreciation)		33,543,839			(43,539,079	)		13,668,274			(16,390,777	)
Net increase (decrease) in net assets resulting from operations		62,767,760			(19,007,654	)		24,395,529			(7,657,845	)
CAPITAL TRANSACTIONS
Proceeds from contributions		49,917,186			40,965,197			30,739,999			20,024,006
Value of withdrawals		(73,367,892	)		(90,655,654	)		(30,540,395	)		(44,881,949	)
Net increase (decrease) in net assets derived from capital transactions		(23,450,706	)		(49,690,457	)		199,604			(24,857,943	)
NET ASSETS
Total increase (decrease) in net assets		39,317,054			(68,698,111	)		24,595,133			(32,515,788	)
Beginning of year		250,172,949			318,871,060			89,238,375			121,754,163
End of year	$	289,490,003		$	250,172,949		$	113,833,508		$	89,238,375

See notes to financial statements.

78 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets  (continued)

	LifePath Dynamic 2060 Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	70,630		$	48,027
Net realized gain		154,529			7,257
Net change in unrealized appreciation (depreciation)		450,786			(247,964	)
Net increase (decrease) in net assets resulting from operations		675,945			(192,680	)
CAPITAL TRANSACTIONS
Proceeds from contributions		1,856,825			139,290
Value of withdrawals		(361,963	)		(81,792	)
Net increase in net assets derived from capital transactions		1,494,862			57,498
NET ASSETS
Total increase (decrease) in net assets		2,170,807			(135,182	)
Beginning of year		2,127,685			2,262,867
End of year	$	4,298,492		$	2,127,685

See notes to financial statements.

FINANCIAL STATEMENTS 79

Financial Highlights

	LifePath Dynamic Retirement Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		17.32	%		(3.35	)%		12.06	%		6.28	%		(1.02	)%
Ratios to Average Net Assets(a)
Total expenses		0.52	%		0.54	%		0.54	%		0.54	%		0.54	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.22	%		0.21	%		0.23	%		0.26	%
Net investment income		3.03	%		2.65	%		2.05	%		2.06	%		1.88	%
Supplemental Data
Net assets, end of year (000)	$	408,522		$	107,643		$	138,424		$	155,750		$	254,167
Portfolio turnover rate(b)		35	%		38	%		6	%		37	%		21	%

^(a)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019

	Range of Periods
Large Cap Index Master Portfolio		2015
Master Small Cap Index Series		2015 — 2018
Master Total Return Portfolio		2016 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.07	%		0.05	%		0.06	%		0.04	%		0.03	%
Investments in underlying funds		0.08	%		0.09	%		0.12	%		0.10	%		0.09	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2018

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares exchange-traded funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

80 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

	LifePath Dynamic 2030 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		22.50	%		(5.15	)%		18.08	%		7.61	%		(1.55	)%
Ratios to Average Net Assets(a)
Total expenses		0.52	%		0.52	%		0.50	%		0.52	%		0.52	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.21	%		0.20	%		0.21	%		0.21	%
Net investment income		2.52	%		2.40	%		2.04	%		2.11	%		1.93	%
Supplemental Data
Net assets, end of year (000)	$	350,842		$	307,428		$	396,907		$	448,317		$	543,847
Portfolio turnover rate(b)		32	%		29	%		21	%		61	%		21	%

^(a)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019

	Range of Periods
Large Cap Index Master Portfolio		2015 — 2015
Master Small Cap Index Series		2015 — 2018
Master Total Return Portfolio		2016 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.10	%		0.08	%		0.08	%		0.06	%		0.05	%
Investments in underlying funds		0.10	%		0.11	%		0.14	%		0.12	%		0.14	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2018

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares exchange-traded funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 81

Financial Highlights  (continued)

	LifePath Dynamic 2040 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		26.15	%		(7.16	)%		21.86	%		8.35	%		(1.79	)%
Ratios to Average Net Assets(a)
Total expenses		0.51	%		0.51	%		0.50	%		0.50	%		0.50	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.20	%		0.19	%		0.19	%		0.18	%
Net investment income		2.44	%		2.25	%		1.99	%		2.13	%		1.94	%
Supplemental Data
Net assets, end of year (000)	$	289,490		$	250,173		$	318,871		$	361,343		$	425,956
Portfolio turnover rate(b)		35	%		39	%		30	%		77	%		19	%

^(a)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019

	Range of Periods
Large Cap Index Master Portfolio		2015
Master Small Cap Index Series		2015 — 2018
Master Total Return Portfolio		2015 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.11	%		0.09	%		0.10	%		0.07	%		0.06	%
Investments in underlying funds		0.12	%		0.13	%		0.16	%		0.14	%		0.17	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2018

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares exchange-traded funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

82 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

	LifePath Dynamic 2050 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		26.82	%		(7.95	)%		23.28	%		8.57	%		(1.96	)%
Ratios to Average Net Assets(a)
Total expenses		0.53	%		0.53	%		0.51	%		0.51	%		0.51	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.20	%		0.18	%		0.19	%		0.17	%
Net investment income		2.39	%		2.05	%		2.02	%		2.09	%		1.94	%
Supplemental Data
Net assets, end of year (000)	$	113,834		$	89,238		$	121,754		$	116,568		$	114,904
Portfolio turnover rate(b)		42	%		43	%		35	%		70	%		36	%

^(a)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019

	Range of Periods
Large Cap Index Master Portfolio		2015
Master Small Cap Index Series		2015 — 2018
Master Total Return Portfolio		2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.12	%		0.09	%		0.09	%		0.07	%		0.07	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.19	%		0.17	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2018

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares exchange-traded funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b) Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 83

Financial Highlights  (continued)

	LifePath Dynamic 2060 Master Portfolio
	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Total Return
Total return		26.91	%(b)		(8.32	)%		11.93	%(c)
Ratios to Average Net Assets(d)
Total expenses		1.46	%		1.62	%		1.54	%(e)(f)
Total expenses after fees waived and/or reimbursed		0.20	%		0.19	%		0.20	%(e)
Net investment income		2.58	%		2.11	%		2.27	%(e)
Supplemental Data
Net assets, end of period (000)	$	4,298		$	2,128		$	2,263
Portfolio turnover rate(g)		44	%		58	%		35	%

^(a)  Commencement of operations.

^(b)  Includes payment received from an affiliate, which impacted the Fund’s total return. Excluding the payment from an affiliate, the Fund’s total return is 26.80%.

^(c)  Aggregate total return.

^(d)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2017 — 2019
CoreAlpha Bond Master Portfolio		2017 — 2019

	Range of Periods
International Tilts Master Portfolio		2017 — 2019
Master Total Return Portfolio		2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,						Period from 05/31/17 (a) to 12/31/17
	2019			2018
Allocated fees waived		0.11	%		0.08	%		0.09	%
Investments in underlying funds		0.13	%		0.14	%		0.23	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Treasury		2017 — 2019
BlackRock Commodity Strategies Fund		2017 — 2019

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2017 — 2019
iShares exchange-traded funds		2017 — 2019

^(e)  Annualized.

^(f)  Audit costs were not annualized in the calculation of the expense ratios. If these expenses were annualized, the total expenses would have been 2.00%.

^(g)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

84 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. The financial statements and these accompanying notes relate to five series of MIP: LifePath^® Dynamic Retirement Master Portfolio, LifePath^® Dynamic 2030 Master Portfolio, LifePath^® Dynamic 2040 Master Portfolio, LifePath^® Dynamic 2050 Master Portfolio and LifePath^® Dynamic 2060 Master Portfolio (each, a “LifePath Dynamic Master Portfolio” and together, the “LifePath Dynamic Master Portfolios”). Each LifePath Dynamic Master Portfolio is classified as diversified.

As of period end, the investment of LifePath Dynamic Retirement Master Portfolio, LifePath Dynamic 2030 Master Portfolio, LifePath Dynamic 2040 Master Portfolio, LifePath Dynamic 2050 Master Portfolio and LifePath Dynamic 2060 Master Portfolio in Active Stock Master Portfolio represented 22.2%, 35.8%, 47.1%, 52.4% and 52.0%, respectively, of net assets. The investment of LifePath Dynamic Retirement Master Portfolio, LifePath Dynamic 2030 Master Portfolio, LifePath Dynamic 2040 Master Portfolio, LifePath Dynamic 2050 Master Portfolio and LifePath Dynamic 2060 Master Portfolio in CoreAlpha Bond Master Portfolio represented 39.3%, 20.7%, 6.5%, 0.8% and 0.9%, respectively, of net assets. As such, financial statements of the Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio, including the Schedules of Investments, should be read in conjunction with each respective LifePath Dynamic Master Portfolio’s financial statements. Active Stock Master Portfolio’s and CoreAlpha Bond Master Portfolio’s financial statements are available, without charge, on the U.S. Securities and Exchange Commission’s (“SEC’s”) website at sec.gov.

The LifePath Dynamic Master Portfolios will generally invest in other registered investment companies (each, an “Underlying Fund” and collectively, the “Underlying Funds”) that are managed by subsidiaries of BlackRock, Inc. (“BlackRock”) and its affiliates, which are affiliates of the LifePath Dynamic Master Portfolios. The LifePath Dynamic Master Portfolios may also invest in other master portfolios (“Underlying Master Portfolios”) that are managed by subsidiaries of BlackRock.

The value of a LifePath Dynamic Master Portfolio’s investment in each of Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio reflects that LifePath Dynamic Master Portfolio’s proportionate interest in the net assets of that Underlying Master Portfolio. As of period end, the LifePath Dynamic Master Portfolios held interests in Underlying Master Portfolios as follows:

	Active Stock Master Portfolio			CoreAlpha Bond Master Portfolio			International Tilts Master Portfolio			Master Total Return Portfolio
LifePath Dynamic Retirement Master Portfolio		17.9	%		8.3	%		11.4	%		0.19	%
LifePath Dynamic 2030 Master Portfolio		24.7			3.7			21.2			0.08
LifePath Dynamic 2040 Master Portfolio		26.9			1.0			24.7			0.02
LifePath Dynamic 2050 Master Portfolio		11.8			0.0			11.5			0.0
LifePath Dynamic 2060 Master Portfolio		0.4			0.0			0.5			0.0

The LifePath Dynamic Master Portfolios, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, are included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

On November 12-13, 2019, the Board of Trustees of MIP (the “Board”) approved a proposal pursuant to which each “feeder” fund will cease to invest in its corresponding LifePath Dynamic Master Portfolio as part of a “master-feeder” structure and instead each “feeder” fund will operate as a stand-alone fund. These changes are expected to be effective on or about March 9, 2020.

Reorganization: The Board of Trustees of MIP approved the reorganization of LifePath Dynamic 2020 Master Portfolio (the “Target Master Portfolio”) into LifePath Dynamic Retirement Master Portfolio. As a result, the LifePath Dynamic Retirement Master Portfolio acquired substantially all of the assets and assumed substantially all of the liabilities of the Target Master Portfolio in exchange for an equal aggregate value of newly-issued interests of the LifePath Dynamic Retirement Master Portfolio.

On November 18, 2019, all of the portfolio securities previously held by the Target Master Portfolio were subsequently contributed to the LifePath Dynamic Retirement Master Portfolio in exchange for an investment in LifePath Dynamic Retirement Master Portfolio.

For financial reporting purposes, assets received by LifePath Dynamic Retirement Master Portfolio were recorded at fair value. However, the cost basis of the investments received from the Target Master Portfolio was carried forward to align ongoing reporting of the LifePath Dynamic Retirement Master Portfolio’s realized and unrealized gains and losses with amounts distributable to shareholders of BlackRock LifePath Dynamic Retirement Fund for tax purposes.

The Target Master Portfolio’s net assets and composition of net assets on November 15, 2019, the valuation date of the reorganization were as follows:

	Target Master Portfolio
Net assets	$	255,409,896
Investors’ Capital		201,044,365
Net Unrealized Appreciation		54,365,531

The net assets of LifePath Dynamic Retirement Master Portfolio before the reorganization were $147,936,865. The aggregate net assets of LifePath Dynamic Retirement Master Portfolio immediately after the reorganization amounted to $403,346,761. The Target Master Portfolio’s fair value and cost of investments and derivative financial instruments prior to the reorganization were as follows:

Target Master Portfolio	Fair Value of Investments		Cost of Investments
LifePath Dynamic 2020 Master Portfolio	$	231,779,407	$	177,413,876

NOTESTO FINANCIAL STATEMENTS 85

Notes to Financial Statements  (continued)

The purpose of these transactions was to combine two funds managed by the Manager with substantially similar (but not identical) investment objectives, investment policies, strategies, risks and restrictions. The reorganization was atax-free event and was effective on November 18, 2019.

Assuming the reorganization had been completed on January 1, 2019, the beginning of the fiscal reporting period of the LifePath Dynamic Retirement Master Portfolio, the pro forma results of operations for the year ended December 31, 2019, are as follows:

• Net investment income: $9,865,049

• Net realized and change in unrealized gain on investments: $46,792,653

• Net increase in net assets resulting from operations: $56,657,702

Because the combined investment portfolios have been managed as a single integrated portfolio since the reorganization was completed, it is not practicable to separate the amounts of revenue and earnings of the Target Master Portfolio that have been included in LifePath Dynamic Retirement Master Portfolio’s Statements of Operations since November 18, 2019.

Reorganization costs incurred by LifePath Dynamic Retirement Master Portfolio in connection with the reorganization were expensed by LifePath Dynamic Retirement Master Portfolio.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. Each LifePath Dynamic Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the LifePath Dynamic Master Portfolios are informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain.

Each LifePath Dynamic Master Portfolio records daily its proportionate share of the Underlying Master Portfolios’ income, expenses and realized and unrealized gains and losses.

Foreign Currency Translation:Each LifePath Dynamic Master Portfolio’s books and records are maintained in U.S. dollars. Securities and other assets and liabilities denominated in foreign currencies are translated into U.S. dollars using exchange rates determined as of the close of trading on the New York Stock Exchange (“NYSE”). Purchases and sales of investments are recorded at the rates of exchange prevailing on the respective dates of such transactions. Generally, when the U.S. dollar rises in value against a foreign currency, the investments denominated in that currency will lose value; the opposite effect occurs if the U.S. dollar falls in relative value.

Each LifePath Dynamic Master Portfolio does not isolate the portion of the results of operations arising as a result of changes in the exchange rates from the changes in the market prices of investments held or sold for financial reporting purposes. Accordingly, the effects of changes in exchange rates on investments are not segregated in the Statements of Operations from the effects of changes in market prices of those investments, but are included as a component of net realized and unrealized gain (loss) from investments. Each LifePath Dynamic Master Portfolio reports realized currency gains (losses) on foreign currency related transactions as components of net realized gain (loss) for financial reporting purposes, whereas such components are generally treated as ordinary income for U.S. federal income tax purposes.

Segregation and Collateralization:In cases where a LifePath Dynamic Master Portfolio enters into certain investments (e.g., futures contracts and forward foreign currency exchange contracts) that would be treated as “senior securities” for 1940 Act purposes, a LifePath Dynamic Master Portfolio may segregate or designate on its books and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment or borrowings to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the LifePath Dynamic Master Portfolios may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, a LifePath Dynamic Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. A LifePath Dynamic Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against a LifePath Dynamic Master Portfolio, which cannot be predicted with any certainty.

Other:Expenses directly related to a LifePath Dynamic Master Portfolio are charged to that LifePath Dynamic Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies:The LifePath Dynamic Master Portfolios’ investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the NYSE (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the LifePath Dynamic Master Portfolios would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The LifePath Dynamic Master

86 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Portfolios determine the fair values of their financial instruments using various independent dealers or pricing services under policies approved by the Board. The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies:The following methods and inputs are used to establish the fair value of each LifePath Dynamic Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

Generally, trading in foreign instruments is substantially completed each day at various times prior to the close of trading on the NYSE. Occasionally, events affecting the values of such instruments may occur between the foreign market close and the close of trading on the NYSE that may not be reflected in the computation of the LifePath Dynamic Master Portfolios’ net assets. Each business day, the LifePath Dynamic Master Portfolios use a pricing service to assist with the valuation of certain foreign exchange-traded equity securities and foreign exchange-traded andover-the-counter (“OTC”) options (the “Systematic Fair Value Price”). Using current market factors, the Systematic Fair Value Price is designed to value such foreign securities and foreign options at fair value as of the close of trading on the NYSE, which follows the close of the local markets.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

• Forward foreign currency exchange contracts are valued at the mean between the bid and ask prices and are determined as of the close of trading on the NYSE based on that day’s prevailing forward exchange rate for the underlying currencies. Interpolated values are derived when the settlement date of the contract is an interim date for which quotations are not available.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that each LifePath Dynamic Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

Fair Value Hierarchy:Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that each LifePath Dynamic Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

As of December 31, 2019, certain investments of the LifePath Dynamic Master Portfolios were valued using NAV as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

4. SECURITIES AND OTHER INVESTMENTS

Securities Lending:Certain LifePath Dynamic Master Portfolios may lend their securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the LifePath Dynamic Master Portfolios collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by each LifePath Dynamic Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at

NOTESTO FINANCIAL STATEMENTS 87

Notes to Financial Statements  (continued)

a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the LifePath Dynamic Master Portfolio and any additional required collateral is delivered to the LifePath Dynamic Master Portfolio, or excess collateral returned by the LifePath Dynamic Master Portfolio, on the next business day. During the term of the loan, the LifePath Dynamic Master Portfolios are entitled to all distributions made on or in respect of the loaned securities, but do not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as investment companies in the LifePath Dynamic Master Portfolios’ Schedules of Investments, and the value of any related collateral are shown separately in the Statements of Assets and Liabilities as a component of investments at value — unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedules of Investments.

Securities lending transactions are entered into by the LifePath Dynamic Master Portfolios under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the LifePath Dynamic Master Portfolios, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and a LifePath Dynamic Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the LifePath Dynamic Master Portfolios’ securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
LifePath Dynamic Retirement Master Portfolio
Morgan Stanley & Co. LLC	$	180,612	$	(180,612	)	$	—
Scotia Capital (USA), Inc.		68,508		(68,508	)		—
	$	249,120	$	(249,120	)	$	—
LifePath Dynamic 2030 Master Portfolio
Bank of America N.A.	$	862,618	$	(862,618	)	$	—
Scotia Capital (USA), Inc.		105,876		(105,876	)		—
Virtu Americas, LLC		37,368		(37,368	)		—
Wells Fargo Securities, LLC		56,052		(56,052	)		—
	$	1,061,914	$	(1,061,914	)	$	—
LifePath Dynamic 2040 Master Portfolio
Bank of America N.A.	$	3,615,291	$	(3,615,291	)	$	—
LifePath Dynamic 2050 Master Portfolio
Bank of America N.A.	$	2,858,652	$	(2,858,652	)	$	—

^(a)  Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by each LifePath Dynamic Master Portfolio is disclosed in the LifePath Dynamic Master Portfolio‘s Statements of Assets and Liabilities.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the LifePath Dynamic Master Portfolios benefit from a borrower default indemnity provided by BlackRock.BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. Each LifePath Dynamic Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the LifePath Dynamic Master Portfolios.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The LifePath Dynamic Master Portfolios engage in various portfolio investment strategies using derivative contracts both to increase the returns of the LifePath Dynamic Master Portfolios and/or to manage their exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedules of Investments. These contracts may be transacted on an exchange or OTC.

Futures Contracts:Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

Futures contracts are agreements between the LifePath Dynamic Master Portfolios and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the LifePath Dynamic Master Portfolios are required to deposit initial

88 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statements of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedules of Investments and cash deposited, if any, are shown as cash pledged for futures contracts in the Statements of Assets and Liabilities. Pursuant to the contract, the LifePath Dynamic Master Portfolios agree to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statements of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statements of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

Forward Foreign Currency Exchange Contracts:Forward foreign currency exchange contracts are entered into to gain or reduce exposure to foreign currencies (foreign currency exchange rate risk).

A forward foreign currency exchange contract is an agreement between two parties to buy and sell a currency at a set exchange rate on a specified date. These contracts help to manage the overall exposure to the currencies in which some of the investments held by the LifePath Dynamic Master Portfolios are denominated and in some cases, may be used to obtain exposure to a particular market.

The contract ismarked-to-market daily and the change in market value is recorded as unrealized appreciation (depreciation) in the Statements of Assets and Liabilities. When a contract is closed, a realized gain or loss is recorded in the Statements of Operations equal to the difference between the value at the time it was opened and the value at the time it was closed.Non-deliverable forward foreign currency exchange contracts are settled with the counterparty in cash without the delivery of foreign currency. The use of forward foreign currency exchange contracts involves the risk that the value of a forward foreign currency exchange contract changes unfavorably due to movements in the value of the referenced foreign currencies, and such value may exceed the amounts reflected in the Statements of Assets and Liabilities. Cash amounts pledged for forward foreign currency exchange contracts are considered restricted and are included in cash pledged as collateral for OTC derivatives in the Statements of Assets and Liabilities.

Master Netting Arrangements: In order to define their contractual rights and to secure rights that will help mitigate their counterparty risk, the LifePath Dynamic Master Portfolios may enter into an International Swaps and Derivatives Association, Inc. Master Agreement (“ISDA Master Agreement”) or similar agreement with their counterparties. An ISDA Master Agreement is a bilateral agreement between each LifePath Dynamic Master Portfolio and a counterparty that governs certain OTC derivatives and typically contains, among other things, collateral posting terms and netting provisions in the event of a default and/or termination event. Under an ISDA Master Agreement, each LifePath Dynamic Master Portfolio may, under certain circumstances, offset with the counterparty certain derivative financial instruments’ payables and/or receivables with collateral held and/or posted and create one single net payment. The provisions of the ISDA Master Agreement typically permit a single net payment in the event of default including the bankruptcy or insolvency of the counterparty. Bankruptcy or insolvency laws of a particular jurisdiction may restrict or prohibit the right of offset in bankruptcy, insolvency or other events.

Collateral Requirements:For derivatives traded under an ISDA Master Agreement, the collateral requirements are typically calculated by netting themark-to-market amount for each transaction under such agreement and comparing that amount to the value of any collateral currently pledged by the LifePath Dynamic Master Portfolio and the counterparty.

Cash collateral that has been pledged to cover obligations of the LifePath Dynamic Master Portfolios and cash collateral received from the counterparty, if any, is reported separately in the Statements of Assets and Liabilities as cash pledged as collateral and cash received as collateral, respectively.Non-cash collateral pledged by the LifePath Dynamic Master Portfolios, if any, is noted in the Schedules of Investments. Generally, the amount of collateral due from or to a counterparty is subject to a certain minimum transfer amount threshold before a transfer is required, which is determined at the close of business of the LifePath Dynamic Master Portfolios. Any additional required collateral is delivered to/pledged by the LifePath Dynamic Master Portfolios on the next business day. Typically, the counterparty is not permitted to sell,re-pledge or use cash andnon-cash collateral it receives. A LifePath Dynamic Master Portfolio generally agrees not to usenon-cash collateral that it receives but may, absent default or certain other circumstances defined in the underlying ISDA Master Agreement, be permitted to use cash collateral received. In such cases, interest may be paid pursuant to the collateral arrangement with the counterparty. To the extent amounts due to the LifePath Dynamic Master Portfolios from their counterparties are not fully collateralized, they bear the risk of loss from counterpartynon-performance. Likewise, to the extent the LifePath Dynamic Master Portfolios have delivered collateral to a counterparty and stand ready to perform under the terms of their agreement with such counterparty, they bear the risk of loss from a counterparty in the amount of the value of the collateral in the event the counterparty fails to return such collateral. Based on the terms of agreements, collateral may not be required for all derivative contracts.

For financial reporting purposes, the LifePath Dynamic Master Portfolios do not offset derivative assets and derivative liabilities that are subject to netting arrangements, if any, in the Statements of Assets and Liabilities.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the LifePath Dynamic Master Portfolios, entered into an Investment Advisory Agreement with the Manager, the LifePath Dynamic Master Portfolios’ investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of each LifePath Dynamic Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of each LifePath Dynamic Master Portfolio.

For such services, each LifePath Dynamic Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.35% of the average daily value of each LifePath Dynamic Master Portfolio’s net assets.

NOTESTO FINANCIAL STATEMENTS 89

Notes to Financial Statements  (continued)

With respect to each LifePath Dynamic Master Portfolio, the Manager entered into separatesub-advisory agreements with BlackRock International Limited (“BIL”) and BlackRock (Singapore) Limited (“BRS”) (collectively, the“Sub-Advisers”), each an affiliate of the Manager. The Manager pays eachSub-Adviser for services it provides for that portion of each LifePath Dynamic Master Portfolio for which it acts assub-adviser, a monthly fee that is equal to a percentage of the investment advisory fees paid by each LifePath Dynamic Master Portfolio to the Manager.

Administration:MIP, on behalf of the LifePath Dynamic Master Portfolios, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the LifePath Dynamic Master Portfolios’ ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the LifePath Dynamic Master Portfolios. BAL may delegate certain of its administration duties tosub-administrators.

BAL is not entitled to compensation for providing administrative services to the LifePath Dynamic Master Portfolios, for so long as BAL (or an affiliate) is entitled to compensation for providing administrative services to corresponding feeder funds that invest substantially all of their assets in the LifePath Dynamic Master Portfolios, or BAL (or an affiliate) receives investment advisory fees from the LifePath Dynamic Master Portfolios.

Expense Limitations and Waivers: BFA, with respect to each LifePath Dynamic Master Portfolio, has contractually agreed to waive 0.30% of its investment advisory fees through April 30, 2020 for each LifePath Dynamic Master Portfolio other than the LifePath Dynamic Retirement Master Portfolio (for which the contractual waiver is in effect through April 30, 2021). These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. For the year ended December 31, 2019, the amounts waived and/or reimbursed were as follows:

	Amounts Waived
LifePath Dynamic Retirement Master Portfolio	$	474,281
LifePath Dynamic 2030 Master Portfolio		1,001,741
LifePath Dynamic 2040 Master Portfolio		817,531
LifePath Dynamic 2050 Master Portfolio		311,349
LifePath Dynamic 2060 Master Portfolio		8,188

With respect to each LifePath Dynamic Master Portfolio, the Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees each LifePath Dynamic Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). However, the Manager does not waive its investment advisory fees by the amount of investment advisory fees paid in connection with each LifePath Dynamic Master Portfolio’s investments in other affiliated investment companies, if any. For the year ended December 31, 2019, the amounts waived were as follows:

	Amounts Waived
LifePath Dynamic Retirement Master Portfolio	$	6,631
LifePath Dynamic 2030 Master Portfolio		9,224
LifePath Dynamic 2040 Master Portfolio		8,053
LifePath Dynamic 2050 Master Portfolio		4,196
LifePath Dynamic 2060 Master Portfolio		67

The fees and expenses of MIP’s trustees who are not “interested persons” of MIP, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and MIP’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the LifePath Dynamic Master Portfolios. BAL and BFA have contractually agreed to reimburse the LifePath Dynamic Master Portfolios or provide an offsetting credit against the investment advisory fees paid by the LifePath Dynamic Master Portfolios in an amount equal to these independent expenses through April 30, 2029 for each LifePath Dynamic Master Portfolio other than the LifePath Dynamic Retirement Master Portfolio (for which the contractual arrangement is in effect through April 30, 2030). If the LifePath Dynamic Master Portfolios do not pay administration fees, BAL and BFA agree to cap the expenses of each LifePath Dynamic Master Portfolio at the rate at which it pays an investment advisory fee to BFA. These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. For the year ended December 31, 2019, the amounts waived were as follows:

	Amounts Waived
LifePath Dynamic Retirement Master Portfolio	$	28,129
LifePath Dynamic 2030 Master Portfolio		31,801
LifePath Dynamic 2040 Master Portfolio		30,689
LifePath Dynamic 2050 Master Portfolio		27,763
LifePath Dynamic 2060 Master Portfolio		26,031

Securities Lending: The U.S. Securities and Exchange Commission (“SEC”) has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the LifePath Dynamic Master Portfolios, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The LifePath Dynamic Master Portfolios are responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the LifePath Dynamic Master Portfolios bear to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a90-day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

90 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. Each LifePath Dynamic Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, each LifePath Dynamic Master Portfolio retains 82% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, each LifePath Dynamic Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 85% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by each LifePath Dynamic Master Portfolio is shown as securities lending income — affiliated — net in the Statements of Operations. For the year ended December 31, 2019, each LifePath Dynamic Master Portfolio paid BTC the following amounts for securities lending agent services:

	LifePath Dynamic Retirement Master Portfolio		LifePath Dynamic 2030 Master Portfolio		LifePath Dynamic 2040 Master Portfolio		LifePath Dynamic 2050 Master Portfolio		LifePath Dynamic 2060 Master Portfolio
Amount	$	1,226	$	3,725	$	3,831	$	1,869	$	—

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, each LifePath Dynamic Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by each LifePath Dynamic Master Portfolio’s investment policies and restrictions. Each LifePath Dynamic Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the LifePath Dynamic Master Portfolios did not participate in the Interfund Lending Program.

Trustees and Officers: Certain trustees and/or officers of MIP are directors and/or officers of BlackRock or its affiliates.

Each LifePath Dynamic Master Portfolio may invest its positive cash balances in certain money market funds managed by the Manager or an affiliate. The income earned on these temporary cash investments is shown as income-affiliated in the Statements of Operations.

Other Transactions: During the year ended December 31, 2019, LifePath Dynamic 2060 Master Portfolio received a reimbursement of $2,603 from an affiliate, which is included in payment from affiliate in the Statements of Operations, related to an operating event.

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments in the Underlying Funds and Underlying Master Portfolios, and excluding short-term securities, were as follows:

	LifePath Dynamic Retirement Master Portfolio		LifePath Dynamic 2030 Master Portfolio		LifePath Dynamic 2040 Master Portfolio		LifePath Dynamic 2050 Master Portfolio		LifePath Dynamic 2060 Master Portfolio
Purchases	$	73,117,367	$	102,261,929	$	91,765,479	$	40,570,243	$	2,481,827
Sales		53,596,780		144,068,770		126,405,271		47,416,345		1,161,812

8. INCOME TAX INFORMATION

Each LifePath Dynamic Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the LifePath Dynamic Master Portfolios is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the LifePath Dynamic Master Portfolios. Therefore, no U.S. federal income tax provision is required. It is intended that the LifePath Dynamic Master Portfolios’ assets will be managed so an investor in the LifePath Dynamic Master Portfolios can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

Each LifePath Dynamic Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on each LifePath Dynamic Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019 except for LifePath Dynamic 2060 Master Portfolio, which remains open for the period ended December 31, 2017 through the year ended December 31, 2019. The statutes of limitations on each LifePath Dynamic Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

NOTESTO FINANCIAL STATEMENTS 91

Notes to Financial Statements  (continued)

Management has analyzed tax laws and regulations and their application to the LifePath Dynamic Master Portfolios as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the LifePath Dynamic Master Portfolios’ financial statements.

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

	LifePath Dynamic Retirement Master Portfolio			LifePath Dynamic 2030 Master Portfolio			LifePath Dynamic 2040 Master Portfolio			LifePath Dynamic 2050 Master Portfolio			LifePath Dynamic 2060 Master Portfolio
Tax cost	$	319,362,495		$	318,785,567		$	246,561,954		$	97,716,908		$	3,921,373
Gross unrealized appreciation	$	93,108,010		$	46,435,224		$	49,989,188		$	18,901,265		$	373,247
Gross unrealized depreciation		(409,116	)		(14,639,425	)		(4,742,512	)		(114,887	)		(4,653	)
Net unrealized appreciation	$	92,698,894		$	31,795,799		$	45,246,676		$	18,786,378		$	368,594

9. BANK BORROWINGS

MIP, on behalf of the LifePath Dynamic Master Portfolios, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the LifePath Dynamic Master Portfolios may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the LifePath Dynamic Master Portfolios, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statements of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the LifePath Dynamic Master Portfolios did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, certain LifePath Dynamic Master Portfolios invest in securities or other instruments and may enter into certain transactions, and such activities subject each LifePath Dynamic Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. Each LifePath Dynamic Master Portfolio’s prospectus provides details of the risks to which each LifePath Dynamic Master Portfolio is subject.

The LifePath Dynamic Master Portfolios may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk:The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. A LifePath Dynamic Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that a LifePath Dynamic Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. A LifePath Dynamic Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause each LifePath Dynamic Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of a LifePath Dynamic Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which a LifePath Dynamic Master Portfolio invests.

Counterparty Credit Risk:The LifePath Dynamic Master Portfolios may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The LifePath Dynamic Master Portfolios manage counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the LifePath Dynamic Master Portfolios to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the LifePath Dynamic Master Portfolios’ exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statements of Assets and Liabilities, less any collateral held by the LifePath Dynamic Master Portfolios.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

A LifePath Dynamic Master Portfolio’s risk of loss from counterparty credit risk on OTC derivatives is generally limited to the aggregate unrealized gain less the value of any collateral held by such LifePath Dynamic Master Portfolio.

92 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

With exchange-traded futures, there is less counterparty credit risk to the LifePath Dynamic Master Portfolios since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, a LifePath Dynamic Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the LifePath Dynamic Master Portfolios.

Concentration Risk: Certain Funds invest a significant portion of their assets in fixed-income securities and/or use derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Funds may be subject to a greater risk of rising interest rates due to the current period of historically low rates.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the LifePath Dynamic Master Portfolios through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 93

Report of Independent Registered Public Accounting Firm Master Investment Portfolio

To the Board of Trustees of

Master Investment Portfolio and Investors of LifePath^® Dynamic Retirement Master Portfolio, LifePath^® Dynamic 2030 Master Portfolio, LifePath^® Dynamic 2040 Master Portfolio, LifePath^® Dynamic 2050 Master Portfolio and LifePath^® Dynamic 2060 Master Portfolio

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities, including the schedules of investments, of LifePath^® Dynamic Retirement Master Portfolio, LifePath^® Dynamic 2030 Master Portfolio, LifePath^® Dynamic 2040 Master Portfolio, LifePath^® Dynamic 2050 Master Portfolio and LifePath^® Dynamic 2060 Master Portfolio (five of the series constituting Master Investment Portfolio, hereafter collectively referred to as the “Master Portfolios”) as of December 31, 2019, the related statements of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the periods indicated therein (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Master Portfolios as of December 31, 2019, the results of each of their operations for the year then ended, the changes in each of their net assets for each of the two years in the period ended December 31, 2019 and each of the financial highlights for each of the periods indicated therein in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinions

These financial statements are the responsibility of the Master Portfolios’ management. Our responsibility is to express an opinion on the Master Portfolios’ financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolios in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, administrator of the Master Portfolios, transfer agents and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinions.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

94 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of BlackRock Funds III, on behalf of BlackRock LifePath^® Dynamic Retirement Fund, BlackRock LifePath^® Dynamic 2030 Fund, BlackRock LifePath^® Dynamic 2040 Fund, BlackRock LifePath^® Dynamic 2050 Fund and BlackRock LifePath^® Dynamic 2060 Fund, and MIP, on behalf of LifePath^® Dynamic Retirement Master Portfolio, LifePath^® Dynamic 2030 Master Portfolio, LifePath^® Dynamic 2040 Master Portfolio, LifePath^® Dynamic 2050 Master Portfolio, and LifePath^® Dynamic 2060 Master Portfolio, met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the Program’s liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements: The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

STATEMENT REGARDING LIQUIDITY RISK MANAGEMENT PROGRAM 95

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None

96 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.

TRUSTEEAND OFFICER INFORMATION 97

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None
Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”)  Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015) President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate.
(c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015.
(d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex.
(e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

98 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge by calling(800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Sub-Advisers

BlackRock International Limited

Edinburgh EH3 8BL, United Kingdom

BlackRock (Singapore) Limited

079912 Singapore

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Distributor

BlackRock Investments, LLC

New York, NY 10022

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

TRUSTEEAND OFFICER INFORMATION 99

Additional Information

General Information

Householding

The LifePath Dynamic Funds will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the LifePath Dynamic Funds at (800) 441-7762.

Availability of Quarterly Schedule of Investments

The LifePath Dynamic Funds/LifePath Dynamic Master Portfolios file their complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information on Form N-Q. The LifePath Dynamic Funds’/LifePath Dynamic Master Portfolios’ Forms N-PORT and N-Q are available on the SEC’s website at sec.gov. The LifePath Dynamic Funds’/LifePath Dynamic Master Portfolios’ FormsN-Q may also be obtained upon request and without charge by calling (800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the LifePath Dynamic Funds/LifePath Dynamic Master Portfolios use to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling (800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the LifePath Dynamic Funds/LifePath Dynamic Master Portfolios voted proxies relating to securities held in the LifePath Dynamic Funds’/LifePath Dynamic Master Portfolios’ portfolios during the most recent 12-month period ended June 30 is available upon request and without charge (1) atblackrock.com; or by calling (800) 441-7762 and (2) on the SEC’s website at sec.gov.

BlackRock’s Mutual Fund Family

BlackRock offers a diverse lineup of open-end mutual funds crossing all investment styles and managed by experts in equity, fixed-income and tax-exempt investing. Visitblackrock.com for more information.

Shareholder Privileges

Account Information

Call us at (800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visitblackrock.com for more information.

Automatic Investment Plans

Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.

Systematic Withdrawal Plans

Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.

Retirement Plans

Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.

100 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information  (continued)

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding their non-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal non-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose to non-affiliated third parties any non-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. These non-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to non-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the non-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

Glossary of Terms Used in this Report

Currency
CAD	Canadian Dollar
EUR	Euro
USD	United States Dollar
Portfolio Abbreviations
ETF	Exchange-Traded Fund
MSCI	Morgan Stanley Capital International
S&P	Standard and Poor’s

ADDITIONAL INFORMATION 101

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of a LifePath Dynamic Fund unless preceded or accompanied by the LifePath Dynamic Funds’ current prospectus. Past performance results shown in this report should not be considered a representation of future performance. Investment returns and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Statements and other information herein are as dated and are subject to change.

LifePath-12/19-AR

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· BlackRock LifePath^® Dynamic 2025 Fund

· BlackRock LifePath^® Dynamic 2035 Fund

· BlackRock LifePath^® Dynamic 2045 Fund

· BlackRock LifePath^® Dynamic 2055 Fund

· BlackRock LifePath^® Dynamic 2065 Fund

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of each Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call(800) 441-7762 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: (i) accessing the BlackRock website at blackrock.com/edelivery and logging into your accounts, if you hold accounts directly with BlackRock, or (ii) contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summaries		4
About Fund Performance		15
Disclosure of Expenses		16
Derivative Financial Instruments		17
Fund Financial Statements:
Statements of Assets and Liabilities		18
Statements of Operations		19
Statements of Changes in Net Assets		20
Fund Financial Highlights		23
Fund Notes to Financial Statements		48
Fund Report of Independent Registered Public Accounting Firm		55
Important Tax Information		56
Master Portfolio Information		57
Master Portfolio Financial Statements:
Schedules of Investments		59
Statements of Assets and Liabilities		76
Statements of Operations		77
Statements of Changes in Net Assets		78
Master Portfolio Financial Highlights		81
Master Portfolio Notes to Financial Statements		86
Master Portfolio Report of Independent Registered Public Accounting Firm		94
Disclosure of Investment Advisory Agreement		95
Statement Regarding Liquidity Risk Management Program		98
Trustee and Officer Information		99
Additional Information		103
Glossary of Terms Used in this Report		104

3

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic Funds

Portfolio Management Commentary

How did each Fund perform?

The BlackRock LifePath^® Dynamic Funds with target dates of 2025, 2035, 2045, 2055 and 2065 (together, the “LifePath Dynamic Funds”) invest in their respective LifePath^® Dynamic Master Portfolio.

For the12-month period ended December 31, 2019, the LifePath Dynamic Funds with target dates of 2025 and 2035 outperformed their respective custom benchmarks with the exception of LifePath Dynamic 2025 Fund’s Investor C and Class R Shares, which underperformed, and LifePath Dynamic 2035 Fund’s Investor C Shares, which underperformed, and Class R Shares, which performed in line. For the same period, the Class K Shares of the LifePath Dynamic 2045 Fund outperformed its respective custom benchmark, while Institutional Shares, performed in line, and Investor A and Class R Shares, underperformed. The LifePath Dynamic 2055 Fund underperformed its respective custom benchmark for the same period, while the LifePath Dynamic 2065 Fund underperformed its respective custom benchmark for the period since inception (October 30, 2019) through December 31, 2019. The returns for the LifePath Dynamic Funds include fund expenses. The custom benchmarks have no expenses associated with performance.

What factors influenced performance?

BlackRock Advantage Emerging Markets Fund (an equity strategy) and BlackRock Tactical Opportunities Fund (a global tactical asset allocation strategy) detracted from the LifePath Dynamic Funds’ returns as they lagged their respective benchmarks. In terms of macro themes, active currency positioning weighed on returns over the period, and an underweight to U.S.10- and30-year bond futures also modestly detracted.

At an investment strategy level, underlying actively managed strategies were generally the largest positive contributors to active returns, while macro themes also contributed in the nearer-dated vintages. Specifically, CoreAlpha Bond Master Portfolio (a domestic fixed-income strategy), Active Stock Master Portfolio (a diversified equity strategy) and active real estate strategies contributed to returns. With regard to the LifePath Dynamic Funds’ macro themes, an overweight to U.S. equities was the largest contributor to returns for the period.

As part of their investment strategy, the LifePath Dynamic Funds may use derivatives to achieve exposure to a market or to manage risk. At times during the period, the LifePath Dynamic Funds had elevated cash positions that were primarily due to collateral posted against these derivatives. The LifePath Dynamic Funds’ cash balances had no material impact on their respective performance.

Describe recent portfolio activity.

Each LifePath Dynamic Fund has its own time horizon, which affects its acceptable level of risk and, in turn, the strategic allocation of its holdings across asset classes. On a quarterly basis, the strategic allocation of each LifePath Dynamic Fund is systematically adjusted to reflect the shareholders’ remaining investment time horizon.

The LifePath Dynamic Funds entered the period with tactical overweights to U.S. and Japanese equities as expressions of the investment adviser’s macro theme of Global Reflation. As markets rebounded strongly from December 2018 lows, the investment adviser reduced holdings in some of the domestic exposure and all the Japanese exposure. Concurrently, the investment adviser introduced an overweight tofar-dated U.S. bonds (via30-year bond futures) as part of a new theme called U.S. Macro Moderation. This exposure was maintained through the first three quarters of 2019, based on the investment adviser’s belief that the U.S. economy was in a state of relative moderation with limited risk of overheating or falling into deep recession.

As pricing moved in line with expectations, the LifePath Dynamic Funds’ overweight tofar-dated U.S. bonds was removed early in the fourth quarter of 2019. The LifePath Dynamic Funds maintained an overweight to U.S. equities throughout the period and introduced underweights to U.S.10-year and U.S.30-year bond futures in April and May 2019, respectively, as expressions of Global Reflation. This fixed-income positioning reflected the investment adviser’s view that despite the notable slowing in global activity data and dovish shift in global central bank tones, price levels for U.S. bonds had risen to levels inconsistent with fundamentals. These three positions were maintained for the rest of the period, although they were trimmed in the fourth quarter. The LifePath Dynamic Funds entered the period with an overweight to the euro, which was increased near the middle of the period, before being modestly trimmed in the latter half of the period as pricing moved in line with expectations. September’s European Central Bank (“ECB”) policy meeting gave the investment adviser increased conviction that the ECB was reaching the limits of both its willingness and its ability to proactively ease policy. Even as challenges to financial stability linger, the investment adviser expects trends in growth, inflation and policy between the Eurozone and the United States to converge over the coming months, and as such expect this to be supportive of a euro overweight position. The LifePath Dynamic Funds closed an overweight to the Australian dollar toward the middle of the period. With an escalation in global trade tensions weighing on the export-oriented economy, expectations of a rate cut from the Reserve Bank of Australia increased, leaving the theme with limited upside potential.

Describe portfolio positioning at period end.

At period end, each of the LifePath Dynamic Funds was invested according to its respective strategic allocation benchmark within tolerance limits.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic Funds

Glide Path Evolution

Under normal circumstances, the asset allocation of each LifePath Dynamic Fund will change over time according to a “glide path” as each LifePath Dynamic Fund approaches its respective target date. The glide path represents the shifting of asset classes over time. Each LifePath Dynamic Fund’s asset mix becomes more conservative — prior to retirement — as time elapses. This reflects the need for reduced investment risks as retirement approaches and the need for lower volatility of each LifePath Dynamic Fund, which may be a primary source of income after retirement. As each LifePath Dynamic Fund approaches its target date, its asset allocation will shift so that it invests a greater percentage of its assets in fixed-income funds. The asset allocation targets are established by the portfolio managers. The investment team, including the portfolio managers, meets regularly to assess market conditions, review the asset allocation targets of each LifePath Dynamic Fund, and determine whether any changes are required to enable each LifePath Dynamic Fund to achieve its investment objective.

Although the asset allocation targets listed for the glide path are general, long-term targets, BlackRock Fund Advisors (“BFA” or the “Manager”) may adjust the allocation to equity and fixed-income in each LifePath Dynamic Fund, based on an assessment of the current market conditions and the potential contribution of each asset class to the expected risk and return characteristics of each LifePath Dynamic Fund. In general, the adjustments will be limited to +/- 10% relative to the target allocations. BFA may determine, in light of market conditions or other factors, that a greater variation is warranted to protect the LifePath Dynamic Fund or achieve its investment objective.

FUND SUMMARY 5

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2025 Fund

Investment Objective

The investment objective ofBlackRock LifePath Dynamic 2025 Fund (“LifePath^® Dynamic 2025 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2025 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Commencement of operations.

^(b)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(c)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2025 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
06/30/10 to 12/31/10		28.5	%		4.4	%		N/A			4.9	%		18.8	%		N/A			N/A			5.9	%		34.9	%		2.6	%
01/01/11 to 12/31/11		29.8			4.6			N/A			4.8			18.9			15.2	%		1.4	%		3.5			20.3			1.5
01/01/12 to 12/31/12		31.9			5.0			1.0	%		4.7			18.2			35.9			3.3			N/A			N/A			N/A
01/01/13 to 12/31/13		33.7			5.2			3.8			4.3			17.1			32.6			3.3			N/A			N/A			N/A
01/01/14 to 12/31/14		34.3			5.3			3.8			4.5			17.3			31.5			3.3			N/A			N/A			N/A
01/01/15 to 12/31/15		31.0			5.0			3.8			5.3			18.8			33.1			3.0			N/A			N/A			N/A
01/01/16 to 12/31/16		32.4			5.2			3.8			5.2			18.5			31.9			2.9			N/A			N/A			N/A
01/01/17 to 12/31/17		34.9			5.7			3.8			4.7			18.0			29.8			3.1			N/A			N/A			N/A
01/01/18 to 12/31/18		36.5			5.9			N/A			4.5			19.3			30.7			3.1			N/A			N/A			N/A
01/01/19 to 12/31/19		38.1			7.1			N/A			2.5			19.5			29.8			3.0			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 15 for descriptions of the indexes.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2025 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)(b)
				1 Year						5 Years						Since Inception (c)
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		5.64	%		19.46	%		N/A			6.61	%		N/A			8.35	%		N/A
Investor A		5.55			19.16			12.90	%		6.36			5.22	%		8.08			7.47	%
Investor C		5.05			18.25			17.25			5.53			5.53			7.25			7.25
Class K		5.73			19.72			N/A			6.87			N/A			8.58			N/A
Class R		5.34			18.91			N/A			6.14			N/A			7.83			N/A
LifePath® Dynamic 2025 Fund Custom Benchmark		6.09			19.02			N/A			6.36			N/A			8.31			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.38			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.07			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			9.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			6.71			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			15.10			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			12.71			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 15 for a detailed description of share classes, including any related sales charges and fees.

^(b)  Effective November 7, 2016, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a Global Tactical Asset Allocation into its glidepath, (ii) increase the flexibility of its equity allocations and (iii) diversify its fixed-income strategies. Performance for the periods shown between December 14, 2015 and November 7, 2016 is based on the prior investment strategy. Effective December 14, 2015, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a dynamic glidepath and (ii) invest directly in securities and derivatives, as well as in underlying funds. Performance for the periods shown prior to December 14, 2015 is based on the prior investment strategy. Effective November 28, 2014, the Fund changed its glide path and target asset allocation to target higher levels of equity exposure for LifePath Dynamic Fund throughout the glide path. Performance for the periods shown prior to November 28, 2014 is based on the prior glide path and target asset allocation.

^(c) The LifePath Dynamic Fund commenced operations on June 30, 2010.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 7

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2035 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2035 Fund (“LifePath Dynamic 2035 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2035 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Commencement of operations.

^(b)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(c)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2035 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
06/30/10 to 12/31/10		16.6	%		2.2	%		N/A			6.8	%		22.7	%		N/A			N/A			6.4	%		42.5	%		2.8	%
01/01/11 to 12/31/11		17.8			2.3			N/A			7.0			22.8			18.6	%		1.2	%		3.9			24.7			1.7
01/01/12 to 12/31/12		20.3			2.6			1.0	%		7.2			21.1			44.1			2.7			N/A			N/A			N/A
01/01/13 to 12/31/13		22.1			2.9			3.9			6.9			21.3			40.3			2.6			N/A			N/A			N/A
01/01/14 to 12/31/14		21.4			2.8			3.9			7.6			22.2			39.6			2.5			N/A			N/A			N/A
01/01/15 to 12/31/15		13.2			1.9			3.9			9.8			25.4			43.6			2.2			N/A			N/A			N/A
01/01/16 to 12/31/16		14.7			2.2			3.9			9.9			25.1			42.1			2.1			N/A			N/A			N/A
01/01/17 to 12/31/17		17.1			2.5			4.0			10.0			24.6			40.1			1.7			N/A			N/A			N/A
01/01/18 to 12/31/18		18.4			2.7			N/A			10.3			25.5			41.3			1.8			N/A			N/A			N/A
01/01/19 to 12/31/19		17.1			4.6			N/A			3.7			30.4			41.8			2.4			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 15 for descriptions of the indexes.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2035 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)(b)
				1 Year						5 Years						Since Inception (c)
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		7.31	%		23.66	%		N/A			7.81	%		N/A			9.69	%		N/A
Investor A		7.12			23.37			16.89	%		7.55			6.40	%		9.42			8.80	%
Investor C		6.77			22.43			21.43			6.70			6.70			8.57			8.57
Class K		7.40			23.92			N/A			8.05			N/A			10.05			N/A
Class R		7.09			23.15			N/A			7.32			N/A			9.17			N/A
LifePath® Dynamic 2035 Fund Custom Benchmark		7.72			23.18			N/A			7.53			N/A			9.64			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.38			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.07			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			9.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			6.71			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			15.10			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			12.71			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 15 for a detailed description of share classes, including any related sales charges and fees.

^(b)  Effective November 7, 2016, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a Global Tactical Asset Allocation into its glidepath, (ii) increase the flexibility of its equity allocations and (iii) diversify its fixed-income strategies. Performance for the periods shown between December 14, 2015 and November 7, 2016 is based on the prior investment strategy. Effective December 14, 2015, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a dynamic glidepath and (ii) invest directly in securities and derivatives, as well as in underlying funds. Performance for the periods shown prior to December 14, 2015 is based on the prior investment strategy. Effective November 28, 2014, the Fund changed its glide path and target asset allocation to target higher levels of equity exposure for LifePath Dynamic Fund throughout the glide path. Performance for the periods shown prior to November 28, 2014 is based on the prior glide path and target asset allocation.

^(c)  The LifePath Dynamic Fund commenced operations on June 30, 2010.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 9

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2045 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2045 Fund (“LifePath Dynamic 2045 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2045 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Commencement of operations.

^(b)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(c)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2045 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
06/30/10 to 12/31/10		6.8	%		N/A			N/A			8.5	%		25.9	%		N/A			N/A			6.8	%		49.0	%		3.0	%
01/01/11 to 12/31/11		8.2			N/A			N/A			8.7			26.1			21.5	%		1.1	%		4.2			28.4			1.8
01/01/12 to 12/31/12		11.2			N/A			1.0	%		9.2			25.3			51.0			2.3			N/A			N/A			N/A
01/01/13 to 12/31/13		13.5			N/A			3.9			9.1			24.8			46.7			2.0			N/A			N/A			N/A
01/01/14 to 12/31/14		12.5			N/A			3.9			10.1			25.9			45.6			2.0			N/A			N/A			N/A
01/01/15 to 12/31/15		1.8			0.2	%		4.2			13.4			29.6			48.8			2.0			N/A			N/A			N/A
01/01/16 to 12/31/16		2.3			0.2			4.3			13.6			29.8			47.8			1.8			N/A			N/A			N/A
01/01/17 to 12/31/17		3.4			0.3			4.3			14.4			29.9			46.7			1.0			N/A			N/A			N/A
01/01/18 to 12/31/18		4.0			0.4			N/A			15.0			30.6			48.9			1.1			N/A			N/A			N/A
01/01/19 to 12/31/19		3.0			1.4			N/A			4.6			38.5			50.5			2.0			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 15 for descriptions of the indexes.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2045 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)(b)
				1 Year						5 Years						Since Inception (c)
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		8.23	%		26.38	%		N/A			8.42	%		N/A			10.65	%		N/A
Investor A		8.10			26.05			19.43	%		8.16			7.00	%		10.38			9.76	%
Investor C		7.69			25.07			24.07			7.31			7.31			9.53			9.53
Class K		8.39			26.67			N/A			8.69			N/A			10.97			N/A
Class R		8.00			25.83			N/A			7.94			N/A			10.13			N/A
LifePath® Dynamic 2045 Fund Custom Benchmark		8.89			26.33			N/A			8.30			N/A			10.64			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.38			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.07			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			9.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			6.71			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			15.10			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			12.71			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 15 for a detailed description of share classes, including any related sales charges and fees.

^(b) Effective November 7, 2016, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a Global Tactical Asset Allocation into its glidepath, (ii) increase the flexibility of its equity allocations and (iii) diversify its fixed-income strategies. Performance for the periods shown between December 14, 2015 and November 7, 2016 is based on the prior investment strategy. Effective December 14, 2015, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a dynamic glidepath and (ii) invest directly in securities and derivatives, as well as in underlying funds. Performance for the periods shown prior to December 14, 2015 is based on the prior investment strategy. Effective November 28, 2014, the Fund changed its glide path and target asset allocation to target higher levels of equity exposure for LifePath Dynamic Fund throughout the glide path. Performance for the periods shown prior to November 28, 2014 is based on the prior glide path and target asset allocation.

^(c)  The LifePath Dynamic Fund commenced operations on June 30, 2010.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 11

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2055 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2055 Fund (“LifePath Dynamic 2055 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2055 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Commencement of operations.

^(b)  Assuming maximum sales charges, transaction costs and other operating expenses, including advisory fees, if any. Institutional Shares do not have a sales charge.

^(c)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2055 Fund Custom Benchmark”) comprised of the indexes indicated below, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index			Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)			Bloomberg Commodity Index (a)			FTSE EPRA Nareit Developed Index			MSCI ACWI ex USA IMI Index			Russell 1000® Index			Russell 2000® Index			S&P MidCap 400® Index			S&P 500® Index			S&P SmallCap 600® Index
06/30/10 to 12/31/10		1.0	%		N/A			N/A			9.0	%		28.2	%		N/A			N/A			8.1	%		50.1	%		3.6	%
01/01/11 to 12/31/11		1.0			N/A			N/A			9.7			28.8			22.0	%		2.0	%		4.9			29.5			2.1
01/01/12 to 12/31/12		1.3			N/A			1.0	%		11.3			28.6			54.5			3.3			N/A			N/A			N/A
01/01/13 to 12/31/13		3.1			N/A			4.1			11.5			27.8			51.7			1.8			N/A			N/A			N/A
01/01/14 to 12/31/14		4.0			N/A			4.0			12.2			28.6			49.4			1.8			N/A			N/A			N/A
01/01/15 to 12/31/15		1.0			N/A			4.2			13.7			29.9			49.2			2.0			N/A			N/A			N/A
01/01/16 to 12/31/16		1.0			N/A			4.4			14.1			30.4			48.3			1.8			N/A			N/A			N/A
01/01/17 to 12/31/17		1.0			N/A			4.3			15.3			30.9			47.5			1.0			N/A			N/A			N/A
01/01/18 to 12/31/18		1.0			N/A			N/A			16.1			31.8			50.1			1.0			N/A			N/A			N/A
01/01/19 to 12/31/19		0.8			0.2	%		N/A			4.8			40.2			52.0			2.0			N/A			N/A			N/A

^(a)  Prior to July 1, 2014, the Bloomberg Commodity Index was known as the Dow Jones-UBS Commodity Index.

See “About Fund Performance” on page 15 for descriptions of the indexes.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) BlackRock LifePath^® Dynamic 2055 Fund

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)(b)
				1 Year						5 Years						Since Inception (c)
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		8.58	%		26.48	%		N/A			8.41	%		N/A			10.98	%		N/A
Investor A		8.47			26.12			19.50	%		8.15			6.99	%		10.70			10.07	%
Investor C		8.03			25.17			24.17			7.28			7.28			9.85			9.85
Class K		8.78			26.75			N/A			8.67			N/A			11.33			N/A
Class R		8.37			25.89			N/A			7.90			N/A			10.44			N/A
LifePath® Dynamic 2055 Fund Custom Benchmark		9.11			26.95			N/A			8.41			N/A			11.09			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		2.45			8.72			N/A			3.05			N/A			3.38			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		2.15			8.43			N/A			2.62			N/A			3.07			N/A
FTSE EPRA Nareit Developed Index		6.46			21.91			N/A			5.56			N/A			9.37			N/A
MSCI ACWI ex USA IMI Index		7.33			21.63			N/A			5.71			N/A			6.71			N/A
Russell 1000® Index		10.59			31.43			N/A			11.48			N/A			15.10			N/A
Russell 2000® Index		7.30			25.52			N/A			8.23			N/A			12.71			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 15 for a detailed description of share classes, including any related sales charges and fees.

^(b)  Effective November 7, 2016, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a Global Tactical Asset Allocation into its glidepath, (ii) increase the flexibility of its equity allocations and (iii) diversify its fixed-income strategies. Performance for the periods shown between December 14, 2015 and November 7, 2016 is based on the prior investment strategy. Effective December 14, 2015, LifePath Dynamic Fund changed its investment strategy to (i) incorporate a dynamic glidepath and (ii) invest directly in securities and derivatives, as well as in underlying funds. Performance for the periods shown prior to December 14, 2015 is based on the prior investment strategy. Performance for the periods shown prior to November 28, 2014 is based on the prior glide path and target asset allocation.

^(c)  The LifePath Dynamic Fund commenced operations on June 30, 2010.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

FUND SUMMARY 13

Fund Summary  as of December 31, 2019 BlackRock LifePath^® Dynamic 2065 Fund

Investment Objective

The investment objective ofBlackRock LifePath^® Dynamic 2065 Fund (“LifePath Dynamic 2065 Fund” or the “LifePath Dynamic Fund”) is to seek to provide for retirement outcomes based on quantitatively measured risk. In pursuit of this objective, LifePath Dynamic 2065 Fund will be broadly diversified across global asset classes, with asset allocations becoming more conservative over time.

The LifePath Dynamic Fund’s custom benchmark consists of the following:

Period	Bloomberg Barclays U.S. Aggregate Bond Index		Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L)		FTSE EPRA Nareit Developed Index		MSCI ACWI ex USA IMI Index		Russell 1000® Index		Russell 2000® Index
10/30/19 to 12/31/19		1.0		0.0		4.8		40.2		52.0		2.0

See “About Fund Performance” on page 15 for descriptions of the indexes.

Performance Summary for the Period Ended December 31, 2019

	Total Returns (a)(b)
	Since Inception (c)
	w/o sales charge			w/sales charge
Institutional		5.36	%		N/A
Investor A		5.32			(0.21	)%
Investor C		5.18			4.18
Class K		5.49			N/A
Class R		5.28			N/A
LifePath® Dynamic 2065 Fund Custom Benchmark		5.69			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		0.41			N/A
Bloomberg Barclays U.S. TIPS Index (Series L)		1.08			N/A
FTSE EPRA Nareit Developed Index		(0.52	)		N/A
MSCI ACWI ex USA IMI Index		5.56			N/A
Russell 1000® Index		6.42			N/A
Russell 2000® Index		6.42			N/A

^(a)  Assuming maximum sales charges, if any. Aggregate total returns with and without sales charges reflect reductions for distributions and service fees. See “About Fund Performance” on page 15 for a detailed description of share classes, including any related sales charges and fees.

^(b)  The LifePath Dynamic Fund compares its performance to that of a customized weighted index (the “LifePath Dynamic 2065 Fund Custom Benchmark”) comprised of the indexes indicated above, which reflects the investment adviser’s changes to the benchmark’s weightings over time. The investment adviser adjusts the weightings of these indexes periodically based upon its evaluation and adjustment of the LifePath Dynamic Fund’s asset allocation strategy. The weightings are presented annually but they are adjusted quarterly.

^(c)  The LifePath Dynamic Fund commenced operations on October 30, 2019.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

About Fund Performance

Institutional and Class K Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors.

Investor A Shares are subject to a maximum initial sales charge (front-end load) of 5.25% and a service fee of 0.25% per year (but no distribution fee). Certain redemptions of these shares may be subject to a contingent deferred sales charge (“CDSC”) where no initial sales charge was paid at the time of purchase. These shares are generally available through financial intermediaries.

Investor C Shares are subject to a 1.00% CDSC if redeemed within one year of purchase. In addition, these shares are subject to a distribution fee of 0.75% per year and a service fee of 0.25% per year. These shares are generally available through financial intermediaries. These shares automatically convert to Investor A Shares after approximately ten years.

Class R Shares are not subject to any sales charge. These shares are subject to a distribution fee of 0.25% per year and a service fee of 0.25% per year. These shares are available only to certain employer-sponsored retirement plans.

Performance information reflects past performance and does not guarantee future results. Current performance may be lower or higher than the performance data quoted. Refer toblackrock.com to obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on LifePath Dynamic Fund distributions or the redemption of LifePath Dynamic Fund shares. Figures shown in each of the performance tables on the previous pages assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend date. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of service, distribution and transfer agency fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (“BAL” or the “Administrator”), each LifePath Dynamic Fund’s administrator, has contractually agreed to waive and/or reimburse a portion of each LifePath Dynamic Fund’s expenses. Without such waiver and/or reimbursement, each LifePath Dynamic Fund’s performance would have been lower. With respect to each Fund’s contractual waiver, the Administrator is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See Note 4 of the Notes to Financial Statements for additional information on waivers and/or reimbursements.

The LifePath Dynamic Funds’ custom benchmarks are hypothetical representations of the performance of the respective LifePath Dynamic Fund’s asset classes according to their weightings as of the most recent quarter-end. The weightings of the various indexes that are included in the LifePath Dynamic Funds’ custom benchmarks are adjusted quarterly to reflect the LifePath Dynamic Funds’ changing asset allocations over time. As of December 31, 2019, the following indexes are used to calculate the LifePath Dynamic Funds’ custom benchmarks: Bloomberg Barclays U.S. Aggregate Bond Index, Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L), FTSE EPRA Nareit Developed Index, MSCI ACWI ex USA IMI Index, Russell 1000^® Index and Russell 2000^® Index, as applicable.

The Bloomberg Barclays U.S. Aggregate Bond Index is a widely recognized unmanaged market-weighted index, comprised of investment-grade corporate bonds rated BBB or better, mortgages and U.S. Treasury and U.S. Government agency issues with at least one year to maturity. The Bloomberg Barclays U.S. Treasury Inflation Protected Securities (TIPS) Index (Series L) is an unmanaged index that measures the performance of the inflation-protected public obligations of the U.S. Treasury. The FTSE EPRA Nareit Developed Index is a global market capitalization weighted index composed of listed real estate securities from developed market countries in North America, Europe and Asia. The MSCI ACWI ex USA IMI Index is a free float-adjusted market capitalization weighted index that measures the equity market performance of the developed (excluding the U.S.) and emerging investable market universe. The Russell 1000^® Index is an index that measures the performance of the large-cap segment of the U.S. equity universe. It is a subset of the Russell 3000^® Index and includes approximately 1,000 of the largest securities based on a combination of their market capitalization and current index membership. The Russell 1000^® Index represents approximately 92% of the total market capitalization of the Russell 3000^® Index. The Russell 2000^® Index is an unmanaged index that is a subset of the Russell 3000^® Index representing approximately 10% of the total market capitalization of that index. It includes approximately 2000 of the smallest securities based on a combination of their market cap and current index membership.

ABOUT FUND PERFORMANCE 15

Disclosure of Expenses

Shareholders of each LifePath^® Dynamic Fund may incur the following charges: (a) transactional expenses, such as sales charges; and (b) operating expenses, including administration fees, service and distribution fees, including 12b-1 fees, acquired fund fees and expenses, and other fund expenses. The expense examples shown below (which are based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019, except with respect to LifePath^® Dynamic 2065 Fund’s Shares which are based on a hypothetical investment of $1,000 on October 30, 2019 (commencement of operations) and held through December 31, 2019) are intended to assist shareholders both in calculating expenses based on an investment in each LifePath^® Dynamic Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense examples provide information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their LifePath^® Dynamic Fund and share class under the heading entitled “Expenses Paid During the Period.”

The expense examples also provide information about hypothetical account values and hypothetical expenses based on a LifePath^® Dynamic Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in a LifePath^® Dynamic Fund and other funds, compare the 5% hypothetical examples with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense examples are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical examples are useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

Expense Examples

	Actual						Hypothetical (b)
	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
LifePath® Dynamic 2025 Fund
Institutional	$	1,000.00	$	1,056.40	$	2.80	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,055.50		4.09		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,050.50		8.22		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,057.30		1.81		1,000.00		1,023.44		1.79		0.35
Class R		1,000.00		1,053.40		5.18		1,000.00		1,020.16		5.09		1.00
LifePath® Dynamic 2035 Fund
Institutional	$	1,000.00	$	1,073.10	$	2.82	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,071.20		4.12		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,067.70		8.29		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,074.00		1.78		1,000.00		1,023.49		1.73		0.34
Class R		1,000.00		1,070.90		5.17		1,000.00		1,020.12		5.04		0.99
LifePath® Dynamic 2045 Fund
Institutional	$	1,000.00	$	1,082.30	$	2.83	$	1,000.00	$	1,022.48	$	2.75		0.54	%
Investor A		1,000.00		1,081.00		4.20		1,000.00		1,021.17		4.08		0.80
Investor C		1,000.00		1,076.90		8.32		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,083.90		1.73		1,000.00		1,023.54		1.68		0.33
Class R		1,000.00		1,080.00		5.24		1,000.00		1,020.16		5.09		1.00
LifePath® Dynamic 2055 Fund
Institutional	$	1,000.00	$	1,085.80	$	2.79	$	1,000.00	$	1,022.53	$	2.70		0.53	%
Investor A		1,000.00		1,084.70		4.15		1,000.00		1,021.22		4.02		0.79
Investor C		1,000.00		1,080.30		8.34		1,000.00		1,017.19		8.08		1.59
Class K		1,000.00		1,087.80		1.74		1,000.00		1,023.54		1.68		0.33
Class R		1,000.00		1,083.70		5.20		1,000.00		1,020.21		5.04		0.99
LifePath® Dynamic 2065 Fund
Institutional	$	1,000.00	$	1,053.60	$	0.98	$	1,000.00	$	1,023.19	$	2.04		0.56	%
Investor A		1,000.00		1,053.20		1.41		1,000.00		1,021.12		4.13		0.81
Investor C		1,000.00		1,058.10		2.81		1,000.00		1,017.09		8.19		1.61
Class K		1,000.00		1,054.90		0.63		1,000.00		1,023.39		1.84		0.36
Class R		1,000.00		1,052.80		1.76		1,000.00		1,020.11		5.14		1.01

^(a)  Expenses for each LifePath^® Dynamic Fund are equal to the annualized expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period shown), except LifePath Dynamic 2065 Fund which is multiplied by 62/365 (to reflect the period since inception date of October 30, 2019). Because each LifePath^® Dynamic Fund invests all of its assets in a LifePath^® Dynamic Master Portfolio, the expense examples reflect the net expenses of both the LifePath^® Dynamic Fund and the LifePath^® Dynamic Master Portfolio in which it invests.

^(b)  Hypothetical 5% return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Derivative Financial Instruments

The LifePath^® Dynamic Master Portfolios may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The LifePath^® Dynamic Master Portfolios’ successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation a LifePath^® Dynamic Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The LifePath^® Dynamic Master Portfolios’ investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.

DERIVATIVE FINANCIAL INSTRUMENTS 17

Statements of Assets and Liabilities

December 31, 2019

	BlackRock LifePath Dynamic 2025 Fund		BlackRock LifePath Dynamic 2035 Fund		BlackRock LifePath Dynamic 2045 Fund		BlackRock LifePath Dynamic 2055 Fund		BlackRock LifePath Dynamic 2065 Fund
ASSETS
Investments at value — from the applicable LifePath Dynamic Master Portfolio	$	69,400,926	$	69,357,383	$	50,475,083	$	27,464,171	$	4,218,303
Receivables:
Capital shares sold		321,994		384,869		361,876		135,016		—
Withdrawals from the Master Portfolio		2,934,225		1,010,443		145,041		230,046		—
Prepaid expenses		—		—		—		—		9,235
Total assets		72,657,145		70,752,695		50,982,000		27,829,233		4,227,538
LIABILITIES
Payables:
Administration fees		27,628		28,399		—		11,227		—
Capital gains distributions		178,058		166,561		154,439		66,784		—
Capital shares redeemed		3,256,219		1,395,312		506,917		365,062		—
Income dividend distributions		44,711		47,132		43,264		20,719		25,978
Professional fees		11,010		11,013		30,609		11,005		10,989
Service and distribution fees		10,872		11,252		7,212		4,779		597
Total liabilities		3,528,498		1,659,669		742,441		479,576		37,564
NET ASSETS	$	69,128,647	$	69,093,026	$	50,239,559	$	27,349,657	$	4,189,974
NET ASSETS CONSIST OF
Paid-in capital	$	63,649,870	$	62,564,386	$	44,738,696	$	24,333,248	$	4,000,000
Accumulated earnings		5,478,777		6,528,640		5,500,863		3,016,409		189,974
NET ASSETS	$	69,128,647	$	69,093,026	$	50,239,559	$	27,349,657	$	4,189,974
NET ASSET VALUE
Institutional
Net assets	$	2,907,979	$	4,003,611	$	4,656,350	$	3,461,278	$	418,999
Shares outstanding(a)		216,618		279,227		304,113		217,660		40,000
Net asset value	$	13.42	$	14.34	$	15.31	$	15.90	$	10.47
Investor A
Net assets	$	23,298,349	$	28,656,161	$	18,811,040	$	13,347,174	$	418,993
Shares outstanding(a)		1,752,914		2,008,164		1,231,546		843,606		40,000
Net asset value	$	13.29	$	14.27	$	15.27	$	15.82	$	10.47
Investor C
Net assets	$	3,416,166	$	3,172,888	$	1,732,352	$	1,212,390	$	418,978
Shares outstanding(a)		258,720		224,902		115,218		77,815		40,000
Net asset value	$	13.20	$	14.11	$	15.04	$	15.58	$	10.47
Class K
Net assets	$	34,027,347	$	27,719,565	$	20,936,164	$	7,240,331	$	2,514,014
Shares outstanding(a)		2,561,958		1,907,711		1,352,596		449,248		240,000
Net asset value	$	13.28	$	14.53	$	15.48	$	16.12	$	10.48
Class R
Net assets	$	5,478,806	$	5,540,801	$	4,103,653	$	2,088,484	$	418,990
Shares outstanding(a)		413,031		388,682		269,516		132,352		40,000
Net asset value	$	13.26	$	14.26	$	15.23	$	15.78	$	10.47

^(a)  Unlimited number of shares authorized, no par value.

See notes to financial statements.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Operations

Year Ended December 31, 2019

	BlackRock LifePath Dynamic 2025 Fund			BlackRock LifePath Dynamic 2035 Fund			BlackRock LifePath Dynamic 2045 Fund			BlackRock LifePath Dynamic 2055 Fund			BlackRock LifePath Dynamic 2065 Fund (a)
INVESTMENT INCOME
Net investment income allocated from the applicable LifePath Dynamic Master Portfolio:
Dividends — affiliated	$	924,554		$	1,091,475		$	885,365		$	526,690		$	32,295
Dividends — unaffiliated		31,303			55,712			52,983			32,331			6
Interest — affiliated		694,453			329,189			87,300			34,881			1,038
Securities lending income — affiliated — net		3,369			4,768			3,219			2,125			32
Foreign taxes withheld		(3,008	)		(5,618	)		(5,504	)		(3,295	)		—
Expenses		(364,985	)		(350,529	)		(260,915	)		(162,287	)		(21,894	)
Fees waived		249,390			244,506			184,527			119,205			20,435
Total investment income		1,535,076			1,369,503			946,975			549,650			31,912
FUND EXPENSES
Administration — class specific		160,831			162,412			113,455			70,932			1,601
Service and distribution — class specific		123,276			129,319			83,953			52,529			1,218
Professional		11,000			11,000			11,001			11,000			10,988
Miscellaneous		400			400			171			57			1
Total expenses		295,507			303,131			208,580			134,518			13,808
Less fees waived and/or reimbursed by the Administrator/Manager		(11,000	)		(11,000	)		(11,001	)		(11,000	)		(10,988	)
Total expenses after fees waived and/or reimbursed		284,507			292,131			197,579			123,518			2,820
Net investment income		1,250,569			1,077,372			749,396			426,132			29,092
REALIZED AND UNREALIZED GAIN (LOSS) ALLOCATED FROM THE APPLICABLE LIFEPATH DYNAMIC MASTER PORTFOLIO
Net realized gain (loss) from investments, futures contracts, forward foreign currency exchange contracts and foreign currency transactions		3,266,564			3,684,815			2,917,559			1,582,032			(5,094	)
Net change in unrealized appreciation (depreciation) on investments, futures contracts, forward foreign currency exchange contracts and foreign currency transactions		5,432,682			6,518,973			5,336,792			2,993,610			191,955
Net realized and unrealized gain		8,699,246			10,203,788			8,254,351			4,575,642			186,861
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	9,949,815		$	11,281,160		$	9,003,747		$	5,001,774		$	215,953

^(a)  Commenced operations on October 30, 2019.

See notes to financial statements.

FINANCIAL STATEMENTS 19

Statements of Changes in Net Assets

	BlackRock LifePath Dynamic 2025 Fund						BlackRock LifePath Dynamic 2035 Fund
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	1,250,569		$	1,239,429		$	1,077,372		$	976,179
Net realized gain		3,266,564			1,648,991			3,684,815			2,055,236
Net change in unrealized appreciation (depreciation)		5,432,682			(5,135,830	)		6,518,973			(6,158,085	)
Net increase (decrease) in net assets resulting from operations		9,949,815			(2,247,410	)		11,281,160			(3,126,670	)
DISTRIBUTIONS(a)
Institutional		(137,717	)		(558,096	)		(193,339	)		(461,901	)
Investor A		(1,256,631	)		(2,457,257	)		(1,468,527	)		(2,937,914	)
Investor C		(135,798	)		(205,437	)		(131,352	)		(249,689	)
Class K		(1,545,875	)		(863,497	)		(1,218,744	)		(696,327	)
Class R		(264,445	)		(435,198	)		(257,255	)		(319,829	)
Decrease in net assets resulting from distributions to shareholders		(3,340,466	)		(4,519,485	)		(3,269,217	)		(4,665,660	)
CAPITAL SHARE TRANSACTIONS
Net increase (decrease) in net assets derived from capital share transactions		18,562,231			(14,612,544	)		18,501,665			(4,777,641	)
NET ASSETS
Total increase (decrease) in net assets		25,171,580			(21,379,439	)		26,513,608			(12,569,971	)
Beginning of year		43,957,067			65,336,506			42,579,418			55,149,389
End of year	$	69,128,647		$	43,957,067		$	69,093,026		$	42,579,418

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets  (continued)

	BlackRock LifePath Dynamic 2045 Fund						BlackRock LifePath Dynamic 2055 Fund
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	749,396		$	593,819		$	426,132		$	321,733
Net realized gain		2,917,559			1,228,479			1,582,032			528,522
Net change in unrealized appreciation (depreciation)		5,336,792			(4,585,218	)		2,993,610			(2,494,402	)
Net increase (decrease) in net assets resulting from operations		9,003,747			(2,762,920	)		5,001,774			(1,644,147	)
DISTRIBUTIONS(a)
Institutional		(225,986	)		(460,490	)		(155,902	)		(253,416	)
Investor A		(933,152	)		(1,819,866	)		(622,770	)		(1,096,533	)
Investor C		(71,164	)		(146,766	)		(46,497	)		(75,457	)
Class K		(902,351	)		(464,820	)		(298,269	)		(183,243	)
Class R		(190,658	)		(314,270	)		(92,006	)		(80,950	)
Decrease in net assets resulting from distributions to shareholders		(2,323,311	)		(3,206,212	)		(1,215,444	)		(1,689,599	)
CAPITAL SHARE TRANSACTIONS
Net increase (decrease) in net assets derived from capital share transactions		13,648,807			(339,644	)		6,591,286			1,104,216
NET ASSETS
Total increase (decrease) in net assets		20,329,243			(6,308,776	)		10,377,616			(2,229,530	)
Beginning of year		29,910,316			36,219,092			16,972,041			19,201,571
End of year	$	50,239,559		$	29,910,316		$	27,349,657		$	16,972,041

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 21

Statements of Changes in Net Assets  (continued)

	BlackRock LifePath Dynamic 2065 Fund
	Period from 10/30/19 (a) to 12/31/19
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	29,092
Net realized loss		(5,094	)
Net change in unrealized appreciation (depreciation)		191,955
Net increase in net assets resulting from operations		215,953
DISTRIBUTIONS(b)
Institutional		(2,636	)
Investor A		(2,462	)
Investor C		(1,906	)
Class K		(16,652	)
Class R		(2,323	)
Decrease in net assets resulting from distributions to shareholders		(25,979	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		4,000,000
NET ASSETS
Total increase in net assets		4,189,974
Beginning of period		—
End of period	$	4,189,974

^(a)  Commencement of operations.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2025 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.81		$	13.52		$	12.66		$	12.05		$	12.80
Net investment income(a)		0.30			0.25			0.22			0.21			0.19
Net realized and unrealized gain (loss)		1.99			(0.87	)		1.71			0.61			(0.44	)
Net increase (decrease) from investment operations		2.29			(0.62	)		1.93			0.82			(0.25	)
Distributions(b)
From net investment income		(0.27	)		(0.24	)		(0.21	)		(0.21	)		(0.21	)
From net realized gain		(0.41	)		(0.85	)		(0.86	)		(0.00	)(c)		(0.28	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.68	)		(1.09	)		(1.07	)		(0.21	)		(0.50	)
Net asset value, end of year	$	13.42		$	11.81		$	13.52		$	12.66		$	12.05
Total Return(d)
Based on net asset value		19.46	%		(4.66	)%		15.45	%		6.88	%		(1.92	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.57	%		0.57	%		0.56	%		0.58	%		0.74	%
Total expenses after fees waived and/or reimbursed		0.55	%		0.55	%		0.54	%		0.57	%		0.71	%
Net investment income		2.32	%		1.87	%		1.66	%		1.74	%		1.51	%
Supplemental Data
Net assets, end of year (000)	$	2,908		$	1,519		$	19,134		$	26,146		$	27,821
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		35	%(g)		38	%(g)		32	%(g)		54	%(g)		51	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.43	%		0.41	%		0.41	%		0.40	%		0.40	%
Investments in underlying funds		0.10	%		0.10	%		0.14	%		0.11	%		0.13	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 23

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2025 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.70		$	13.50		$	12.64		$	12.04		$	12.78
Net investment income(a)		0.26			0.26			0.20			0.18			0.16
Net realized and unrealized gain (loss)		1.98			(0.91	)		1.70			0.60			(0.43	)
Net increase (decrease) from investment operations		2.24			(0.65	)		1.90			0.78			(0.27	)
Distributions(b)
From net investment income		(0.24	)		(0.30	)		(0.18	)		(0.18	)		(0.18	)
From net realized gain		(0.41	)		(0.85	)		(0.86	)		(0.00	)(c)		(0.28	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.65	)		(1.15	)		(1.04	)		(0.18	)		(0.47	)
Net asset value, end of year	$	13.29		$	11.70		$	13.50		$	12.64		$	12.04
Total Return(d)
Based on net asset value		19.16	%		(4.87	)%		15.21	%		6.54	%		(2.17	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.82	%		0.83	%		0.81	%		0.83	%		0.99	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.81	%		0.79	%		0.82	%		0.96	%
Net investment income		1.97	%		1.94	%		1.45	%		1.50	%		1.26	%
Supplemental Data
Net assets, end of year (000)	$	23,298		$	25,940		$	31,393		$	28,135		$	30,373
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		35	%(g)		38	%(g)		32	%(g)		54	%(g)		51	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.43	%		0.41	%		0.41	%		0.40	%		0.40	%
Investments in underlying funds		0.10	%		0.10	%		0.14	%		0.11	%		0.13	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2025 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.63		$	13.44		$	12.58		$	11.99		$	12.72
Net investment income(a)		0.16			0.16			0.09			0.08			0.06
Net realized and unrealized gain (loss)		1.96			(0.92	)		1.70			0.59			(0.42	)
Net increase (decrease) from investment operations		2.12			(0.76	)		1.79			0.67			(0.36	)
Distributions(b)
From net investment income		(0.14	)		(0.20	)		(0.07	)		(0.08	)		(0.09	)
From net realized gain		(0.41	)		(0.85	)		(0.86	)		(0.00	)(c)		(0.27	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.55	)		(1.05	)		(0.93	)		(0.08	)		(0.37	)
Net asset value, end of year	$	13.20		$	11.63		$	13.44		$	12.58		$	11.99
Total Return(d)
Based on net asset value		18.25	%		(5.70	)%		14.39	%		5.61	%		(2.86	)%
Ratios to Average Net Assets(e)(f)
Total expenses		1.62	%		1.63	%		1.61	%		1.63	%		1.75	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.61	%		1.59	%		1.62	%		1.72	%
Net investment income		1.25	%		1.17	%		0.66	%		0.69	%		0.51	%
Supplemental Data
Net assets, end of year (000)	$	3,416		$	2,434		$	2,583		$	2,339		$	2,900
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		35	%(g)		38	%(g)		32	%(g)		54	%(g)		51	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.43	%		0.41	%		0.41	%		0.40	%		0.40	%
Investments in underlying funds		0.10	%		0.10	%		0.14	%		0.11	%		0.13	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 25

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2025 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.69		$	13.49		$	12.63		$	12.03		$	12.78
Net investment income(a)		0.34			0.33			0.27			0.25			0.25
Net realized and unrealized gain (loss)		1.96			(0.91	)		1.69			0.59			(0.45	)
Net increase (decrease) from investment operations		2.30			(0.58	)		1.96			0.84			(0.20	)
Distributions(b)
From net investment income		(0.30	)		(0.37	)		(0.24	)		(0.24	)		(0.26	)
From net realized gain		(0.41	)		(0.85	)		(0.86	)		(0.00	)(c)		(0.28	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.71	)		(1.22	)		(1.10	)		(0.24	)		(0.55	)
Net asset value, end of year	$	13.28		$	11.69		$	13.49		$	12.63		$	12.03
Total Return(d)
Based on net asset value		19.72	%		(4.43	)%		15.75	%		7.02	%		(1.64	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.37	%		0.38	%		0.36	%		0.38	%		0.41	%
Total expenses after fees waived and/or reimbursed		0.35	%		0.36	%		0.34	%		0.37	%		0.38	%
Net investment income		2.62	%		2.44	%		2.01	%		2.02	%		2.00	%
Supplemental Data
Net assets, end of year (000)	$	34,027		$	9,062		$	7,919		$	2,902		$	1,278
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		35	%(g)		38	%(g)		32	%(g)		54	%(g)		51	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.43	%		0.41	%		0.41	%		0.40	%		0.40	%
Investments in underlying funds		0.10	%		0.10	%		0.14	%		0.11	%		0.13	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2025 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.68		$	13.49		$	12.63		$	12.04		$	12.79
Net investment income(a)		0.24			0.24			0.17			0.16			0.13
Net realized and unrealized gain (loss)		1.97			(0.92	)		1.71			0.59			(0.43	)
Net increase (decrease) from investment operations		2.21			(0.68	)		1.88			0.75			(0.30	)
Distributions(b)
From net investment income		(0.22	)		(0.28	)		(0.16	)		(0.16	)		(0.17	)
From net realized gain		(0.41	)		(0.85	)		(0.86	)		(0.00	)(c)		(0.27	)
From return of capital		—			—			—			—			(0.01	)
Total distributions		(0.63	)		(1.13	)		(1.02	)		(0.16	)		(0.45	)
Net asset value, end of year	$	13.26		$	11.68		$	13.49		$	12.63		$	12.04
Total Return(d)
Based on net asset value		18.91	%		(5.10	)%		15.02	%		6.28	%		(2.36	)%
Ratios to Average Net Assets(e)(f)
Total expenses		1.02	%		1.03	%		1.01	%		1.03	%		1.24	%
Total expenses after fees waived and/or reimbursed		1.00	%		1.01	%		0.99	%		1.02	%		1.21	%
Net investment income		1.82	%		1.77	%		1.27	%		1.32	%		1.06	%
Supplemental Data
Net assets, end of year (000)	$	5,479		$	5,003		$	4,308		$	2,967		$	2,690
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		35	%(g)		38	%(g)		32	%(g)		54	%(g)		51	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.43	%		0.41	%		0.41	%		0.40	%		0.40	%
Investments in underlying funds		0.10	%		0.10	%		0.14	%		0.11	%		0.13	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 27

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2035 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.21		$	14.48		$	13.28		$	12.58		$	13.43
Net investment income(a)		0.30			0.25			0.22			0.23			0.21
Net realized and unrealized gain (loss)		2.58			(1.15	)		2.34			0.72			(0.49	)
Net increase (decrease) from investment operations		2.88			(0.90	)		2.56			0.95			(0.28	)
Distributions(b)
From net investment income		(0.30	)		(0.27	)		(0.26	)		(0.25	)		(0.22	)
From net realized gain		(0.45	)		(1.10	)		(1.10	)		—			(0.35	)
From return of capital		—			—			—			—			(0.00	)(c)
Total distributions		(0.75	)		(1.37	)		(1.36	)		(0.25	)		(0.57	)
Net asset value, end of year	$	14.34		$	12.21		$	14.48		$	13.28		$	12.58
Total Return(d)
Based on net asset value		23.66	%		(6.42	)%		19.51	%		7.61	%		(2.15	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.57	%		0.57	%		0.56	%		0.57	%		0.72	%
Total expenses after fees waived and/or reimbursed		0.55	%		0.55	%		0.53	%		0.55	%		0.68	%
Net investment income		2.20	%		1.71	%		1.54	%		1.77	%		1.54	%
Supplemental Data
Net assets, end of year (000)	$	4,004		$	2,231		$	10,965		$	19,650		$	22,071
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		42	%(g)		40	%(g)		35	%(g)		76	%(g)		44	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.43	%		0.44	%		0.41	%		0.43	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.13	%		0.16	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2035 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016				2015
Net asset value, beginning of year	$	12.15		$	14.46		$	13.26		$	12.56			$	13.41
Net investment income(a)		0.25			0.25			0.20			0.19				0.17
Net realized and unrealized gain (loss)		2.58			(1.19	)		2.33			0.73				(0.48	)
Net increase (decrease) from investment operations		2.83			(0.94	)		2.53			0.92				(0.31	)
Distributions(b)
From net investment income		(0.26	)		(0.27	)		(0.23	)		(0.22	)			(0.19	)
From net realized gain		(0.45	)		(1.10	)		(1.10	)		—				(0.35	)
From return of capital		—			—			—			—				(0.00	)(c)
Total distributions		(0.71	)		(1.37	)		(1.33	)		(0.22	)			(0.54	)
Net asset value, end of year	$	14.27		$	12.15		$	14.46		$	13.26			$	12.56
													��
Total Return(d)
Based on net asset value		23.37	%		(6.69	)%		19.29	%		7.37	%			(2.40	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.82	%		0.82	%		0.81	%		0.82	%			0.97	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.80	%		0.79	%		0.80	%			0.93	%
Net investment income		1.85	%		1.75	%		1.38	%		1.52	%			1.30	%
Supplemental Data
Net assets, end of year (000)	$	28,656		$	27,982		$	32,083		$	29,768			$	30,359
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		42	%(g)		40	%(g)		35	%(g)		76	%(g)			44	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.43	%		0.44	%		0.41	%		0.43	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.13	%		0.16	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 29

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2035 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.02		$	14.33		$	13.15		$	12.47		$	13.32
Net investment income(a)		0.14			0.14			0.08			0.09			0.07
Net realized and unrealized gain (loss)		2.56			(1.19	)		2.32			0.71			(0.48	)
Net increase (decrease) from investment operations		2.70			(1.05	)		2.40			0.80			(0.41	)
Distributions(b)
From net investment income		(0.16	)		(0.16	)		(0.12	)		(0.12	)		(0.09	)
From net realized gain		(0.45	)		(1.10	)		(1.10	)		—			(0.35	)
From return of capital		—			—			—			—			(0.00	)(c)
Total distributions		(0.61	)		(1.26	)		(1.22	)		(0.12	)		(0.44	)
Net asset value, end of year	$	14.11		$	12.02		$	14.33		$	13.15		$	12.47
Total Return(d)
Based on net asset value		22.43	%		(7.47	)%		18.41	%		6.42	%		(3.13	)%
Ratios to Average Net Assets(e)(f)
Total expenses		1.62	%		1.62	%		1.61	%		1.62	%		1.72	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.60	%		1.59	%		1.60	%		1.69	%
Net investment income		1.07	%		0.99	%		0.60	%		0.74	%		0.55	%
Supplemental Data
Net assets, end of year (000)	$	3,173		$	2,609		$	2,436		$	2,112		$	2,007
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		42	%(g)		40	%(g)		35	%(g)		76	%(g)		44	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.43	%		0.44	%		0.41	%		0.43	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.13	%		0.16	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2035 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.36		$	14.68		$	13.45		$	12.74		$	13.60
Net investment income(a)		0.37			0.33			0.28			0.27			0.30
Net realized and unrealized gain (loss)		2.58			(1.22	)		2.34			0.72			(0.54	)
Net increase (decrease) from investment operations		2.95			(0.89	)		2.62			0.99			(0.24	)
Distributions(b)
From net investment income		(0.33	)		(0.33	)		(0.29	)		(0.28	)		(0.27	)
From net realized gain		(0.45	)		(1.10	)		(1.10	)		—			(0.35	)
From return of capital		—			—			—			—			(0.00	)(c)
Total distributions		(0.78	)		(1.43	)		(1.39	)		(0.28	)		(0.62	)
Net asset value, end of year	$	14.53		$	12.36		$	14.68		$	13.45		$	12.74
Total Return(d)
Based on net asset value		23.92	%		(6.23	)%		19.76	%		7.82	%		(1.83	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.36	%		0.37	%		0.36	%		0.36	%		0.39	%
Total expenses after fees waived and/or reimbursed		0.35	%		0.35	%		0.33	%		0.35	%		0.35	%
Net investment income		2.63	%		2.25	%		1.92	%		2.07	%		2.30	%
Supplemental Data
Net assets, end of year (000)	$	27,720		$	6,627		$	5,882		$	2,702		$	757
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		42	%(g)		40	%(g)		35	%(g)		76	%(g)		44	%(h)

^(a) Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.43	%		0.44	%		0.41	%		0.43	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.13	%		0.16	%

^(g)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 31

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2035 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.15		$	14.46		$	13.26		$	12.58		$	13.44
Net investment income(a)		0.24			0.22			0.17			0.18			0.14
Net realized and unrealized gain (loss)		2.57			(1.19	)		2.33			0.71			(0.49	)
Net increase (decrease) from investment operations		2.81			(0.97	)		2.50			0.89			(0.35	)
Distributions(b)
From net investment income		(0.25	)		(0.24	)		(0.20	)		(0.21	)		(0.16	)
From net realized gain		(0.45	)		(1.10	)		(1.10	)		—			(0.35	)
From return of capital		—			—			—			—			(0.00	)(c)
Total distributions		(0.70	)		(1.34	)		(1.30	)		(0.21	)		(0.51	)
Net asset value, end of year	$	14.26		$	12.15		$	14.46		$	13.26		$	12.58
Total Return(d)
Based on net asset value		23.15	%		(6.87	)%		19.08	%		7.10	%		(2.65	)%
Ratios to Average Net Assets(e)(f)
Total expenses		1.02	%		1.02	%		1.01	%		1.02	%		1.21	%
Total expenses after fees waived and/or reimbursed		1.00	%		1.00	%		0.99	%		1.00	%		1.18	%
Net investment income		1.71	%		1.55	%		1.19	%		1.41	%		1.09	%
Supplemental Data
Net assets, end of year (000)	$	5,541		$	3,131		$	3,782		$	3,078		$	867
Portfolio turnover rate of the LifePath Dynamic Master Portfolio		42	%(g)		40	%(g)		35	%(g)		76	%(g)		44	%(h)

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.45	%		0.43	%		0.44	%		0.41	%		0.43	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.13	%		0.16	%
							��

^(g) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

^(h)  Includes the purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio and Master Small Cap Index Series.

See notes to financial statements.

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2045 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.75		$	15.41		$	13.88		$	13.10		$	14.05
Net investment income(a)		0.31			0.26			0.23			0.23			0.21
Net realized and unrealized gain (loss)		3.04			(1.47	)		2.83			0.83			(0.54	)
Net increase (decrease) from investment operations		3.35			(1.21	)		3.06			1.06			(0.33	)
Distributions(b)
From net investment income		(0.31	)		(0.29	)		(0.29	)		(0.28	)		(0.21	)
From net realized gain		(0.48	)		(1.16	)		(1.24	)		—			(0.41	)
Total distributions		(0.79	)		(1.45	)		(1.53	)		(0.28	)		(0.62	)
Net asset value, end of year	$	15.31		$	12.75		$	15.41		$	13.88		$	13.10
Total Return(c)
Based on net asset value		26.38	%		(8.18	)%		22.29	%		8.14	%		(2.37	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.58	%		0.58	%		0.56	%		0.56	%		0.71	%
Total expenses after fees waived and/or reimbursed		0.56	%		0.55	%		0.53	%		0.53	%		0.66	%
Net investment income		2.13	%		1.68	%		1.54	%		1.76	%		1.53	%
Supplemental Data
Net assets, end of year (000)	$	4,656		$	2,967		$	8,267		$	14,864		$	15,105
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		49	%		47	%		46	%		75	%		50	%

^(a) Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.49	%		0.46	%		0.47	%		0.44	%		0.48	%
Investments in underlying funds		0.12	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 33

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2045 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.72		$	15.40		$	13.87		$	13.09		$	14.04
Net investment income(a)		0.26			0.24			0.21			0.20			0.18
Net realized and unrealized gain (loss)		3.05			(1.50	)		2.82			0.83			(0.54	)
Net increase (decrease) from investment operations		3.31			(1.26	)		3.03			1.03			(0.36	)
Distributions(b)
From net investment income		(0.28	)		(0.26	)		(0.26	)		(0.25	)		(0.18	)
From net realized gain		(0.48	)		(1.16	)		(1.24	)		—			(0.41	)
Total distributions		(0.76	)		(1.42	)		(1.50	)		(0.25	)		(0.59	)
Net asset value, end of year	$	15.27		$	12.72		$	15.40		$	13.87		$	13.09
Total Return(c)
Based on net asset value		26.05	%		(8.44	)%		22.05	%		7.90	%		(2.61	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.84	%		0.83	%		0.82	%		0.81	%		0.96	%
Total expenses after fees waived and/or reimbursed		0.81	%		0.80	%		0.78	%		0.78	%		0.91	%
Net investment income		1.82	%		1.56	%		1.38	%		1.52	%		1.28	%
Supplemental Data
Net assets, end of year (000)	$	18,811		$	17,742		$	20,152		$	17,206		$	16,744
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		49	%		47	%		46	%		75	%		50	%

^(a) Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.49	%		0.46	%		0.47	%		0.44	%		0.48	%
Investments in underlying funds		0.12	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2045 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.54		$	15.20		$	13.71		$	12.94		$	13.90
Net investment income(a)		0.15			0.12			0.08			0.09			0.07
Net realized and unrealized gain (loss)		2.99			(1.47	)		2.79			0.82			(0.54	)
Net increase (decrease) from investment operations		3.14			(1.35	)		2.87			0.91			(0.47	)
Distributions(b)
From net investment income		(0.16	)		(0.15	)		(0.14	)		(0.14	)		(0.08	)
From net realized gain		(0.48	)		(1.16	)		(1.24	)		—			(0.41	)
Total distributions		(0.64	)		(1.31	)		(1.38	)		(0.14	)		(0.49	)
Net asset value, end of year	$	15.04		$	12.54		$	15.20		$	13.71		$	12.94
Total Return(c)
Based on net asset value		25.07	%		(9.13	)%		21.10	%		7.04	%		(3.43	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.64	%		1.63	%		1.62	%		1.61	%		1.72	%
Total expenses after fees waived and/or reimbursed		1.61	%		1.60	%		1.58	%		1.58	%		1.67	%
Net investment income		1.04	%		0.78	%		0.56	%		0.70	%		0.53	%
Supplemental Data
Net assets, end of year (000)	$	1,732		$	1,535		$	1,375		$	1,247		$	1,420
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		49	%		47	%		46	%		75	%		50	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.49	%		0.46	%		0.47	%		0.44	%		0.48	%
Investments in underlying funds		0.12	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 35

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2045 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.88		$	15.57		$	14.01		$	13.22		$	14.18
Net investment income(a)		0.39			0.32			0.29			0.27			0.40
Net realized and unrealized gain (loss)		3.03			(1.52	)		2.84			0.83			(0.68	)
Net increase (decrease) from investment operations		3.42			(1.20	)		3.13			1.10			(0.28	)
Distributions(b)
From net investment income		(0.34	)		(0.33	)		(0.33	)		(0.31	)		(0.27	)
From net realized gain		(0.48	)		(1.16	)		(1.24	)		—			(0.41	)
Total distributions		(0.82	)		(1.49	)		(1.57	)		(0.31	)		(0.68	)
Net asset value, end of year	$	15.48		$	12.88		$	15.57		$	14.01		$	13.22
Total Return(c)
Based on net asset value		26.67	%		(7.99	)%		22.58	%		8.38	%		(2.04	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.37	%		0.38	%		0.37	%		0.36	%		0.40	%
Total expenses after fees waived and/or reimbursed		0.34	%		0.35	%		0.33	%		0.33	%		0.34	%
Net investment income		2.60	%		2.04	%		1.90	%		2.02	%		3.08	%
Supplemental Data
Net assets, end of year (000)	$	20,936		$	4,471		$	3,385		$	1,271		$	524
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		49	%		47	%		46	%		75	%		50	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.49	%		0.46	%		0.47	%		0.44	%		0.48	%
Investments in underlying funds		0.12	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2045 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.69		$	15.37		$	13.85		$	13.09		$	14.04
Net investment income(a)		0.24			0.21			0.19			0.19			0.15
Net realized and unrealized gain (loss)		3.03			(1.49	)		2.80			0.80			(0.53	)
Net increase (decrease) from investment operations		3.27			(1.28	)		2.99			0.99			(0.38	)
Distributions(b)
From net investment income		(0.25	)		(0.24	)		(0.23	)		(0.23	)		(0.16	)
From net realized gain		(0.48	)		(1.16	)		(1.24	)		—			(0.41	)
Total distributions		(0.73	)		(1.40	)		(1.47	)		(0.23	)		(0.57	)
Net asset value, end of year	$	15.23		$	12.69		$	15.37		$	13.85		$	13.09
Total Return(c)
Based on net asset value		25.83	%		(8.63	)%		21.81	%		7.64	%		(2.80	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.04	%		1.03	%		1.02	%		1.01	%		1.21	%
Total expenses after fees waived and/or reimbursed		1.01	%		1.00	%		0.98	%		0.99	%		1.15	%
Net investment income		1.65	%		1.38	%		1.24	%		1.39	%		1.09	%
Supplemental Data
Net assets, end of year (000)	$	4,104		$	3,196		$	3,039		$	1,780		$	693
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		49	%		47	%		46	%		75	%		50	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.49	%		0.46	%		0.47	%		0.44	%		0.48	%
Investments in underlying funds		0.12	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 37

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2055 Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	13.19		$	15.86		$	14.28		$	13.46		$	14.33
Net investment income(a)		0.32			0.26			0.24			0.24			0.22
Net realized and unrealized gain (loss)		3.16			(1.56	)		2.93			0.86			(0.57	)
Net increase (decrease) from investment operations		3.48			(1.30	)		3.17			1.10			(0.35	)
Distributions(b)
From net investment income		(0.31	)		(0.29	)		(0.29	)		(0.28	)		(0.21	)
From net realized gain		(0.46	)		(1.08	)		(1.30	)		—			(0.31	)
Total distributions		(0.77	)		(1.37	)		(1.59	)		(0.28	)		(0.52	)
Net asset value, end of year	$	15.90		$	13.19		$	15.86		$	14.28		$	13.46
Total Return(c)
Based on net asset value		26.48	%		(8.43	)%		22.57	%		8.20	%		(2.52	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.59	%		0.61	%		0.59	%		0.59	%		0.79	%
Total expenses after fees waived and/or reimbursed		0.54	%		0.55	%		0.52	%		0.54	%		0.66	%
Net investment income		2.14	%		1.65	%		1.54	%		1.73	%		1.53	%
Supplemental Data
Net assets, end of year (000)	$	3,461		$	1,748		$	4,863		$	8,626		$	7,381
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		54	%		57	%		59	%		80	%		49	%

^(a) Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.54	%		0.51	%		0.54	%		0.52	%		0.62	%
Investments in underlying funds		0.13	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2055 Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	13.13		$	15.81		$	14.25		$	13.44		$	14.30
Net investment income(a)		0.27			0.24			0.22			0.20			0.19
Net realized and unrealized gain (loss)		3.15			(1.57	)		2.90			0.85			(0.56	)
Net increase (decrease) from investment operations		3.42			(1.33	)		3.12			1.05			(0.37	)
Distributions(b)
From net investment income		(0.27	)		(0.27	)		(0.26	)		(0.24	)		(0.18	)
From net realized gain		(0.46	)		(1.08	)		(1.30	)		—			(0.31	)
Total distributions		(0.73	)		(1.35	)		(1.56	)		(0.24	)		(0.49	)
Net asset value, end of year	$	15.82		$	13.13		$	15.81		$	14.25		$	13.44
Total Return(c)
Based on net asset value		26.12	%		(8.63	)%		22.24	%		7.90	%		(2.67	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.85	%		0.86	%		0.85	%		0.84	%		1.04	%
Total expenses after fees waived and/or reimbursed		0.80	%		0.80	%		0.78	%		0.79	%		0.91	%
Net investment income		1.81	%		1.53	%		1.39	%		1.49	%		1.30	%
Supplemental Data
Net assets, end of year (000)	$	13,347		$	11,583		$	11,416		$	9,317		$	7,561
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		54	%		57	%		59	%		80	%		49	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.54	%		0.51	%		0.54	%		0.52	%		0.62	%
Investments in underlying funds		0.13	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 39

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2055 Fund (continued)
	Investor C
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	12.95		$	15.62		$	14.11		$	13.31		$	14.18
Net investment income(a)		0.16			0.12			0.10			0.09			0.08
Net realized and unrealized gain (loss)		3.10			(1.56	)		2.86			0.85			(0.56	)
Net increase (decrease) from investment operations		3.26			(1.44	)		2.96			0.94			(0.48	)
Distributions(b)
From net investment income		(0.17	)		(0.15	)		(0.15	)		(0.14	)		(0.08	)
From net realized gain		(0.46	)		(1.08	)		(1.30	)		—			(0.31	)
Total distributions		(0.63	)		(1.23	)		(1.45	)		(0.14	)		(0.39	)
Net asset value, end of year	$	15.58		$	12.95		$	15.62		$	14.11		$	13.31
Total Return(c)
Based on net asset value		25.17	%		(9.36	)%		21.24	%		7.05	%		(3.48	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.65	%		1.66	%		1.65	%		1.65	%		1.80	%
Total expenses after fees waived and/or reimbursed		1.60	%		1.60	%		1.58	%		1.59	%		1.67	%
Net investment income		1.08	%		0.75	%		0.62	%		0.70	%		0.54	%
Supplemental Data
Net assets, end of year (000)	$	1,212		$	862		$	729		$	499		$	543
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		54	%		57	%		59	%		80	%		49	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.54	%		0.51	%		0.54	%		0.52	%		0.62	%
Investments in underlying funds		0.13	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2055 Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	13.36		$	16.06		$	14.45		$	13.62		$	14.49
Net investment income(a)		0.40			0.32			0.30			0.28			0.28
Net realized and unrealized gain (loss)		3.16			(1.60	)		2.94			0.86			(0.58	)
Net increase (decrease) from investment operations		3.56			(1.28	)		3.24			1.14			(0.30	)
Distributions(b)
From net investment income		(0.34	)		(0.34	)		(0.33	)		(0.31	)		(0.26	)
From net realized gain		(0.46	)		(1.08	)		(1.30	)		—			(0.31	)
Total distributions		(0.80	)		(1.42	)		(1.63	)		(0.31	)		(0.57	)
Net asset value, end of year	$	16.12		$	13.36		$	16.06		$	14.45		$	13.62
Total Return(c)
Based on net asset value		26.75	%		(8.21	)%		22.79	%		8.42	%		(2.15	)%
Ratios to Average Net Assets(d)(e)
Total expenses		0.39	%		0.41	%		0.40	%		0.37	%		0.46	%
Total expenses after fees waived and/or reimbursed		0.34	%		0.35	%		0.33	%		0.33	%		0.32	%
Net investment income		2.58	%		1.99	%		1.88	%		2.01	%		1.97	%
Supplemental Data
Net assets, end of year (000)	$	7,240		$	1,920		$	1,426		$	425		$	52
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		54	%		57	%		59	%		80	%		49	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e) Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.54	%		0.51	%		0.54	%		0.52	%		0.62	%
Investments in underlying funds		0.13	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 41

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2055 Fund (continued)
	Class R
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	13.11		$	15.80		$	14.25		$	13.44		$	14.32
Net investment income(a)		0.24			0.21			0.19			0.18			0.15
Net realized and unrealized gain (loss)		3.15			(1.58	)		2.89			0.85			(0.57	)
Net increase (decrease) from investment operations		3.39			(1.37	)		3.08			1.03			(0.42	)
Distributions(b)
From net investment income		(0.26	)		(0.24	)		(0.23	)		(0.22	)		(0.15	)
From net realized gain		(0.46	)		(1.08	)		(1.30	)		—			(0.31	)
Total distributions		(0.72	)		(1.32	)		(1.53	)		(0.22	)		(0.46	)
Net asset value, end of year	$	15.78		$	13.11		$	15.80		$	14.25		$	13.44
Total Return(c)
Based on net asset value		25.89	%		(8.87	)%		21.95	%		7.74	%		(3.00	)%
Ratios to Average Net Assets(d)(e)
Total expenses		1.04	%		1.06	%		1.05	%		1.04	%		1.29	%
Total expenses after fees waived and/or reimbursed		1.00	%		1.00	%		0.98	%		0.99	%		1.15	%
Net investment income		1.59	%		1.34	%		1.20	%		1.30	%		1.07	%
Supplemental Data
Net assets, end of year (000)	$	2,088		$	859		$	768		$	483		$	292
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(f)		54	%		57	%		59	%		80	%		49	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.54	%		0.51	%		0.54	%		0.52	%		0.62	%
Investments in underlying funds		0.13	%		0.12	%		0.17	%		0.15	%		0.18	%

^(f)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio, Large Cap Index Master Portfolio, Master Small Cap Index Series and Master Total Return Portfolio.

See notes to financial statements.

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2065 Fund
	Institutional
	Period from 10/30/19 (a) to 12/31/19
Net asset value, beginning of period	$	10.00
Net investment income(b)		0.07
Net realized and unrealized gain		0.47
Net increase from investment operations		0.54
Distributions from net investment income(c)		(0.07	)
Net asset value, end of period	$	10.47
Total Return(d)
Based on net asset value		5.36	%(e)
Ratios to Average Net Assets(f)(g)
Total expenses		0.83	%(h)(i)
Total expenses after fees waived and/or reimbursed		0.56	%(h)
Net investment income		4.23	%(h)
Supplemental Data
Net assets, end of period (000)	$	419
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(j)		3	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Aggregate total return.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income of 2.93%. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds of 0.13%.

^(h)  Annualized.

⁽ⁱ⁾  Audit fees were not annualized in the calculation of expense ratios. If this expense was annualized, the total expenses would have been 2.14%.

^(j)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 43

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2065 Fund (continued)
	Investor A
	Period from 10/30/19 (a) to 12/31/19
Net asset value, beginning of period	$	10.00
Net investment income(b)		0.07
Net realized and unrealized gain		0.46
Net increase from investment operations		0.53
Distributions from net investment income(c)		(0.06	)
Net asset value, end of period	$	10.47
Total Return(d)
Based on net asset value		5.32	%(e)
Ratios to Average Net Assets(f)(g)
Total expenses		1.08	%(h)(i)
Total expenses after fees waived and/or reimbursed		0.81	%(h)
Net investment income		3.98	%(h)
Supplemental Data
Net assets, end of period (000)	$	419
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(j)		3	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Aggregate total return.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income of 2.93%. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds of 0.13%.

^(h)  Annualized.

⁽ⁱ⁾  Audit fees were not annualized in the calculation of expense ratios. If this expense was annualized, the total expenses would have been 2.39%.

^(j)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2065 Fund (continued)
	Investor C
	Period from 10/30/19 (a) to 12/31/19
Net asset value, beginning of period	$	10.00
Net investment income(b)		0.05
Net realized and unrealized gain		0.47
Net increase from investment operations		0.52
Distributions from net investment income(c)		(0.05	)
Net asset value, end of period	$	10.47
Total Return(d)
Based on net asset value		5.18	%(e)
Ratios to Average Net Assets(f)(g)
Total expenses		1.88	%(h)(i)
Total expenses after fees waived and/or reimbursed		1.61	%(h)
Net investment income		3.13	%(h)
Supplemental Data
Net assets, end of period (000)	$	419
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(j)		3	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(e)  Aggregate total return.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income of 2.93%. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds of 0.13%.

^(h)  Annualized.

⁽ⁱ⁾  Audit fees were not annualized in the calculation of expense ratios. If this expense was annualized, the total expenses would have been 3.19%.

^(j)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 45

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2065 Fund (continued)
	Class K
	Period from 10/30/19 (a) to 12/31/19
Net asset value, beginning of period	$	10.00
Net investment income(b)		0.08
Net realized and unrealized gain		0.47
Net increase from investment operations		0.55
Distributions from net investment income(c)		(0.07	)
Net asset value, end of period	$	10.48
Total Return(d)
Based on net asset value		5.49	%(e)
Ratios to Average Net Assets(f)(g)
Total expenses		0.63	%(h)(i)
Total expenses after fees waived and/or reimbursed		0.36	%(h)
Net investment income		4.43	%(h)
Supplemental Data
Net assets, end of period (000)	$	2,514
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(j)		3	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Aggregate total return.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income of 2.93%. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds of 0.13%.

^(h)  Annualized.

⁽ⁱ⁾  Audit fees were not annualized in the calculation of expense ratios. If this expense was annualized, the total expenses would have been 1.94%.

^(j)  Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock LifePath Dynamic 2065 Fund (continued)
	Class R
	Period from 10/30/19 (a) to 12/31/19
Net asset value, beginning of period	$	10.00
Net investment income(b)		0.07
Net realized and unrealized gain		0.46
Net increase from investment operations		0.53
Distributions from net investment income(c)		(0.06	)
Net asset value, end of period	$	10.47
Total Return(d)
Based on net asset value		5.28	%(e)
Ratios to Average Net Assets(f)(g)
Total expenses		1.28	%(h)(i)
Total expenses after fees waived and/or reimbursed		1.01	%(h)
Net investment income		3.78	%(h)
Supplemental Data
Net assets, end of period (000)	$	419
Portfolio turnover rate of the LifePath Dynamic Master Portfolio(j)		3	%

^(a) Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Aggregate total return.

^(f)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated net expenses and/or net investment income.

^(g)  Includes the LifePath Dynamic Fund’s share of its corresponding LifePath Dynamic Master Portfolio’s allocated fees waived and expenses and/or net investment income of 2.93%. Excludes expenses incurred indirectly as a result of the LifePath Dynamic Master Portfolio’s investments in underlying funds of 0.13%.

^(h) Annualized.

⁽ⁱ⁾  Audit fees were not annualized in the calculation of expense ratios. If this expense was annualized, the total expenses would have been 2.59%.

^(j) Includes the LifePath Dynamic Master Portfolio’s purchases and sales of the underlying funds and Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 47

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. The following, each of which is a series of the Trust, are referred to herein collectively as the “LifePath Dynamic Funds” or individually as a “LifePath Dynamic Fund”:

LifePath Dynamic Fund Name	Herein Referred To As	Diversification Classification
BlackRock LifePath® Dynamic 2025 Fund	LifePath Dynamic 2025 Fund	Diversified
BlackRock LifePath® Dynamic 2035 Fund	LifePath Dynamic 2035 Fund	Diversified
BlackRock LifePath® Dynamic 2045 Fund	LifePath Dynamic 2045 Fund	Diversified
BlackRock LifePath® Dynamic 2055 Fund	LifePath Dynamic 2055 Fund	Diversified
BlackRock LifePath® Dynamic 2065 Fund	LifePath Dynamic 2065 Fund	Diversified

Each LifePath Dynamic Fund seeks to achieve its investment objective by investing all of its assets in a corresponding series of Master Investment Portfolio (“MIP”): LifePath Dynamic 2025 Master Portfolio, LifePath Dynamic 2035 Master Portfolio, LifePath Dynamic 2045 Master Portfolio, LifePath Dynamic 2055 Master Portfolio and LifePath Dynamic 2065 Master Portfolio (each, a “LifePath Dynamic Master Portfolio” and together, the “LifePath Dynamic Master Portfolios”). MIP is an affiliate of the Trust. Each LifePath Dynamic Master Portfolio has the same investment objective and strategies as its corresponding LifePath Dynamic Fund. The value of each LifePath Dynamic Fund’s investment in its corresponding LifePath Dynamic Master Portfolio reflects the LifePath Dynamic Fund’s proportionate interest in the net assets of the LifePath Dynamic Master Portfolio. The performance of the LifePath Dynamic Funds is directly affected by the performance of the LifePath Dynamic Master Portfolios. At December 31, 2019, the percentage of each LifePath Dynamic Master Portfolio owned by its corresponding LifePath Dynamic Fund was approximately 100%. The financial statements of the LifePath Dynamic Master Portfolios, including the Schedules of Investments, are included elsewhere in this report and should be read in conjunction with the LifePath Dynamic Funds’ financial statements.

Each LifePath Dynamic Fund offers multiple classes of shares. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that certain classes bear expenses related to the shareholder servicing and distribution of such shares. Institutional and Class K Shares are sold without a sales charge and only to certain eligible investors. Class R Shares are sold without a sales charge and only to certain employer-sponsored retirement plans. Investor A and Investor C Shares are generally available through financial intermediaries. Investor A, Investor C, and Class R Shares bear certain expenses related to shareholder servicing of such shares, and Investor C and Class R Shares also bear certain expenses related to the distribution of such shares. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures (except that Investor C shareholders may vote on material changes to the Investor A Shares distribution and service plan). The Board of Trustees of the Trust and Board of Trustees of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

Share Class	Initial Sales Charge	CDSC			Conversion Privilege
Institutional, Class K and Class R Shares	No		No		None
Investor A Shares	Yes		No	(a)	None
Investor C Shares	No		Yes	(b)	To Investor A Shares after approximately 10 years

^(a)  Investor A Shares may be subject to a contingent deferred sales charge (“CDSC”) for certain redemptions where no initial sales charge was paid at the time of purchase.

^(b)  A CDSC of 1.00% is assessed on certain redemptions of Investor C Shares made within one year after purchase.

The LifePath Dynamic Funds, together with certain other registered investment companies advised by BlackRock Advisors, LLC (“BAL” or the “Administrator”) or its affiliates, are included in a complex equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

On November 12-13, 2019, the Board approved a proposal pursuant to which each LifePath Dynamic Fund will cease to invest in its corresponding “master” portfolio as part of a “master-feeder” structure and instead operate as a stand-alone fund. In connection with this change, the Trust, on behalf of each Fund, will enter into a management agreement with BAL, the terms of which will be substantially the same as the current management agreement between BAL and each corresponding LifePath Dynamic Master Portfolio, including the management fee rate. The change into a stand-alone structure will not create a taxable event for the LifePath Dynamic Funds or their shareholders. These changes are expected to be effective on or about March 9, 2020.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. Each LifePath Dynamic Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from each LifePath Dynamic Master Portfolio are accounted for on a trade date basis. Each LifePath Dynamic Fund records its proportionate share of LifePath Dynamic Master Portfolio’s income, expenses and realized and unrealized gains and losses on a daily basis. Realized and unrealized gains and losses are adjusted utilizing partnership tax allocation rules. In addition, the LifePath Dynamic Funds accrue their own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions from net investment income are declared and paid quarterly. Distributions of capital gains are recorded on theex-dividend date and made at least annually. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

48 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Indemnifications:In the normal course of business, a LifePath Dynamic Fund enters into contracts that contain a variety of representations that provide general indemnification. A LifePath Dynamic Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against a LifePath Dynamic Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to a LifePath Dynamic Fund or its classes are charged to that LifePath Dynamic Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the LifePath Dynamic Funds and other shared expenses prorated to the LifePath Dynamic Funds are allocated daily to each class based on their relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: Each LifePath Dynamic Fund’s policy is to value its financial instruments at fair value. Each LifePath Dynamic Fund records its investment in its corresponding LifePath Dynamic Master Portfolio at fair value based on each LifePath Dynamic Fund’s proportionate interest in the net assets of its corresponding LifePath Dynamic Master Portfolio. Valuation of securities held by the LifePath Dynamic Master Portfolios is discussed in Note 3 of the LifePath Dynamic Master Portfolios’ Notes to Financial Statements, which are included elsewhere in this report.

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration: The Trust, on behalf of the LifePath Dynamic Funds, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL” or the “Administrator”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the LifePath Dynamic Funds’ ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the LifePath Dynamic Funds. BAL is entitled to receive for these administrative services an annual fee of 0.35% based on the average daily net assets of each LifePath Dynamic Fund’s Institutional and Investor A Shares, 0.40% of the average daily net assets of Investor C Shares, 0.15% of the average daily net assets of Class K Shares and 0.30% of the average daily net assets of Class R Shares.

From time to time, BAL may waive such fees in whole or in part. Any such waiver will reduce the expenses of the LifePath Dynamic Funds and, accordingly, have a favorable impact on its performance. BAL may delegate certain of its administration duties tosub-administrators.

For the year ended December 31, 2019, the following table shows the class specific administration fees borne directly by each share class of each LifePath Dynamic Fund:

	Institutional		Investor A		Investor C		Class K		Class R		Total
LifePath Dynamic 2025 Fund	$	8,411	$	95,264	$	11,358	$	29,812	$	15,986	$	160,831
LifePath Dynamic 2035 Fund		11,086		106,820		12,211		18,910		13,385		162,412
LifePath Dynamic 2045 Fund		14,002		68,808		6,702		13,175		10,768		113,455
LifePath Dynamic 2055 Fund		9,206		48,103		4,133		4,862		4,628		70,932
LifePath Dynamic 2065 Fund		244		244		278		626		209		1,601

Service and Distribution Fees: The Trust, on behalf of the LifePath Dynamic Funds, entered into a Distribution Agreement and a Distribution and Service Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Pursuant to the Distribution and Service Plan and in accordance with Rule12b-1 under the 1940 Act, each LifePath Dynamic Fund pays BRIL ongoing service and distribution fees. The fees are accrued daily and paid monthly at annual rates based upon the average daily net assets of the relevant share class of each LifePath Dynamic Fund as follows:

	Service Fees			Distribution Fees
Investor A		0.25	%		—	%
Investor C		0.25			0.75
Class R		0.25			0.25

BRIL and broker-dealers, pursuant tosub-agreements with BRIL, provide shareholder servicing and distribution services to the LifePath Dynamic Funds. The ongoing service and/or distribution fee compensates BRIL and each broker-dealer for providing shareholder servicing and/or distribution related services to shareholders.

For the year ended December 31, 2019, the following table shows the class specific service and distribution fees borne directly by each share class of each LifePath Dynamic Fund:

Service and Distribution Fees	Investor A		Investor C		Class R		Total
LifePath Dynamic 2025 Fund	$	68,062	$	28,418	$	26,796	$	123,276
LifePath Dynamic 2035 Fund		76,304		30,558		22,457		129,319
LifePath Dynamic 2045 Fund		49,182		16,762		18,009		83,953
LifePath Dynamic 2055 Fund		34,399		10,342		7,788		52,529
LifePath Dynamic 2065 Fund		174		696		348		1,218

Other Fees: For the year ended December 31, 2019, affiliates earned underwriting discounts, direct commissions and dealer concessions on sales of each LifePath Dynamic Fund’s Investor A Shares as follows:

	LifePath Dynamic 2025 Fund		LifePath Dynamic 2035 Fund		LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund		LifePath Dynamic 2065 Fund
Investor A	$	1,194	$	308	$	1,656	$	578	$	—

NOTESTO FINANCIAL STATEMENTS 49

Notes to Financial Statements  (continued)

For the year ended December 31, 2019, affiliates received CDSCs as follows:

	LifePath Dynamic 2025 Fund		LifePath Dynamic 2035 Fund		LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund		LifePath Dynamic 2065 Fund
Investor A	$	—	$	32	$	427	$	—	$	—
Investor C		173		188		360		19		—

Expense Waivers and Reimbursements:The fees and expenses of the Trust’s trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the LifePath Dynamic Funds’ independent registered public accounting firm (together, the “independent expenses”) are paid directly by the LifePath Dynamic Funds. BAL has contractually agreed to reimburse the LifePath Dynamic Funds or provide an offsetting credit against the administration fees paid by the LifePath Dynamic Funds in an amount equal to these independent expenses through April 30, 2029. These amounts are included in fees waived and/or reimbursed by the Administrator/Manager in the Statements of Operations. For the year ended year ended December 31, 2019, the LifePath Dynamic Funds waived the following amounts:

	LifePath Dynamic 2025 Fund		LifePath Dynamic 2035 Fund		LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund		LifePath Dynamic 2065 Fund
Amounts waived	$	11,000	$	11,000	$	11,001	$	11,000	$	10,988

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, each LifePath Dynamic Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by each LifePath Dynamic Funds’ investment policies and restrictions. Each LifePath Dynamic Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the LifePath Dynamic Funds did not participate in the Interfund Lending Program.

Trustees and Officers: Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock, Inc. or its affiliates.

5. INCOME TAX INFORMATION

The LifePath Dynamic Fund’s policyto comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

Each LifePath Dynamic Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. Except for LifePath Dynamic 2065 Fund, the statute of limitations on each LifePath Dynamic Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statute of limitations on LifePath Dynamic 2065 Fund’s U.S. federal tax returns generally remains open for the period ended December 31, 2019. The statutes of limitations on each LifePath Dynamic Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the LifePath Dynamic Funds as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the LifePath Dynamic Funds’ financial statements.

The tax character of distributions paid was as follows:

	LifePath Dynamic 2025 Fund			LifePath Dynamic 2035 Fund			LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund		LifePath Dynamic 2065 Fund
Ordinary income
12/31/19	$	1,696,885		$	1,313,415		$	816,299	$	452,442	$	25,979
12/31/18		2,975,989	(a)		2,935,232	(a)		1,995,328		1,044,261		—
Long-term capital gains
12/31/19		1,643,581			1,955,802			1,507,012		763,002		—
12/31/18		1,561,818			1,736,862			1,210,884		645,338		—
Total
12/31/19	$	3,340,466		$	3,269,217		$	2,323,311	$	1,215,444	$	25,979
12/31/18	$	4,537,807		$	4,672,094		$	3,206,212	$	1,689,599		—

^(a)  Distribution amounts may include a portion of the proceeds from redeemed shares.

50 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

As of period end, the tax components of accumulated net earnings (losses) were as follows:

	LifePath Dynamic 2025 Fund		LifePath Dynamic 2035 Fund		LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund		LifePath Dynamic 2065 Fund
Undistributed ordinary income	$	281,279	$	404,747	$	317,357	$	79,158	$	4,394
Undistributed long-term capital gains		307,003		374,136		365,007		269,418		—
Non-expiring Capital loss carryforwards(a)		—		—		—		—		(9,127	)
Net unrealized gains (losses)(b)		4,890,495		5,749,757		4,818,499		2,667,833		194,707
	$	5,478,777	$	6,528,640	$	5,500,863	$	3,016,409	$	189,974

^(a) Amounts available to offset future realized capital gains.

^(b) The difference between book-basis andtax-basis net unrealized gains were attributable primarily to the timing and recognition of partnership income, the tax deferral of losses on wash sales and the realization for tax purposes of unrealized gains/losses on certain futures and foreign currency contracts.

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2025 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		145,686		$	1,886,939			489,610		$	6,605,422
Shares issued in reinvestment of distributions		10,305			137,716			42,602			558,096
Shares redeemed		(68,009	)		(887,130	)		(1,818,550	)		(24,057,969	)
Net increase (decrease)		87,982		$	1,137,525			(1,286,338	)	$	(16,894,451	)
Investor A
Shares sold		450,949		$	5,854,201			440,495		$	5,864,901
Shares issued in reinvestment of distributions		94,968			1,256,631			202,587			2,457,256
Shares redeemed		(1,010,908	)		(13,197,354	)		(750,728	)		(10,048,972	)
Net decrease		(464,991	)	$	(6,086,522	)		(107,646	)	$	(1,726,815	)
Investor C
Shares sold		78,990		$	1,027,278			63,587		$	851,659
Shares issued in reinvestment of distributions		10,304			135,798			17,187			205,438
Shares redeemed		(39,874	)		(514,450	)		(63,741	)		(848,835	)
Net increase		49,420		$	648,626			17,033		$	208,262
Class K
Shares sold		2,102,462		$	27,097,520			255,977		$	3,460,475
Shares issued in reinvestment of distributions		116,758			1,545,874			71,296			863,497
Shares redeemed		(432,577	)		(5,624,969	)		(138,864	)		(1,868,666	)
Net increase		1,786,643		$	23,018,425			188,409		$	2,455,306
Class R
Shares sold		363,664		$	4,788,863			135,645		$	1,748,415
Shares issued in reinvestment of distributions		19,801			261,740			35,815			430,247
Shares redeemed		(398,789	)		(5,206,426	)		(62,477	)		(833,508	)
Net increase (decrease)		(15,324	)	$	(155,823	)		108,983		$	1,345,154
Total Net Increase (Decrease)		1,443,730		$	18,562,231			(1,079,559	)	$	(14,612,544	)

NOTESTO FINANCIAL STATEMENTS 51

Notes to Financial Statements  (continued)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2035 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		152,746		$	2,104,437			264,562		$	3,852,104
Shares issued in reinvestment of distributions		13,570			193,338			34,223			461,900
Shares redeemed		(69,828	)		(967,536	)		(873,258	)		(12,371,104	)
Net increase (decrease)		96,488		$	1,330,239			(574,473	)	$	(8,057,100	)
Investor A
Shares sold		445,966		$	6,179,054			341,803		$	4,898,137
Shares issued in reinvestment of distributions		103,630			1,468,415			232,227			2,937,697
Shares redeemed		(844,234	)		(11,720,338	)		(490,579	)		(6,976,676	)
Net increase (decrease)		(294,638	)	$	(4,072,869	)		83,451		$	859,158
Investor C
Shares sold		62,286		$	841,570			78,177		$	1,111,289
Shares issued in reinvestment of distributions		9,307			130,917			20,065			248,781
Shares redeemed		(63,644	)		(872,735	)		(51,344	)		(730,860	)
Net increase		7,949		$	99,752			46,898		$	629,210
Class K
Shares sold		1,464,322		$	20,534,910			124,283		$	1,822,958
Shares issued in reinvestment of distributions		84,177			1,218,744			54,096			696,327
Shares redeemed		(176,844	)		(2,480,509	)		(42,967	)		(621,229	)
Net increase		1,371,655		$	19,273,145			135,412		$	1,898,056
Class R
Shares sold		387,779		$	5,403,856			59,883		$	858,849
Shares issued in reinvestment of distributions		17,770			251,907			25,185			317,943
Shares redeemed		(274,592	)		(3,784,365	)		(88,925	)		(1,283,757	)
Net increase (decrease)		130,957		$	1,871,398			(3,857	)	$	(106,965	)
Total Net Increase (Decrease)		1,312,411		$	18,501,665			(312,569	)	$	(4,777,641	)
	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2045 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		126,649		$	1,801,837			178,525		$	2,736,810
Shares issued in reinvestment of distributions		14,884			225,986			32,974			460,490
Shares redeemed		(70,053	)		(1,017,500	)		(515,232	)		(7,743,615	)
Net increase (decrease)		71,480		$	1,010,323			(303,733	)	$	(4,546,315	)
Investor A
Shares sold		255,882		$	3,710,591			261,383		$	3,961,941
Shares issued in reinvestment of distributions		61,642			933,153			136,045			1,819,866
Shares redeemed		(480,543	)		(7,046,358	)		(311,698	)		(4,780,156	)
Net increase (decrease)		(163,019	)	$	(2,402,614	)		85,730		$	1,001,651
Investor C
Shares sold		43,427		$	623,790			56,674		$	858,315
Shares issued in reinvestment of distributions		4,748			71,162			11,223			146,758
Shares redeemed		(55,389	)		(795,393	)		(35,947	)		(544,148	)
Net increase (decrease)		(7,214	)	$	(100,441	)		31,950		$	460,925
Class K
Shares sold		1,066,982		$	15,664,635			139,803		$	2,184,070
Shares issued in reinvestment of distributions		58,405			900,712			34,106			461,838
Shares redeemed		(119,834	)		(1,760,033	)		(44,264	)		(677,975	)
Net increase		1,005,553		$	14,805,314			129,645		$	1,967,933
Class R
Shares sold		172,411		$	2,543,252			61,622		$	935,397
Shares issued in reinvestment of distributions		12,607			190,657			23,659			314,270
Shares redeemed		(167,375	)		(2,397,684	)		(31,151	)		(473,505	)
Net increase		17,643		$	336,225			54,130		$	776,162
Total Net Increase (Decrease)		924,443		$	13,648,807			(2,278	)	$	(339,644	)

52 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

	Year Ended 12/31/19						Year Ended 12/31/18
LifePath Dynamic 2055 Fund	Shares			Amount			Shares			Amount
Institutional
Shares sold		109,862		$	1,655,918			147,737		$	2,339,289
Shares issued in reinvestment of distributions		9,887			155,902			17,583			253,415
Shares redeemed		(34,573	)		(519,889	)		(339,454	)		(5,267,062	)
Net increase (decrease)		85,176		$	1,291,931			(174,134	)	$	(2,674,358	)
Investor A
Shares sold		267,843		$	4,016,695			220,170		$	3,454,479
Shares issued in reinvestment of distributions		39,725			622,770			79,904			1,096,534
Shares redeemed		(346,288	)		(5,263,361	)		(139,976	)		(2,183,477	)
Net increase (decrease)		(38,720	)	$	(623,896	)		160,098		$	2,367,536
Investor C
Shares sold		29,384		$	437,909			34,855		$	540,249
Shares issued in reinvestment of distributions		2,994			46,497			5,620			75,457
Shares redeemed		(21,106	)		(315,539	)		(20,564	)		(314,579	)
Net increase		11,272		$	168,867			19,911		$	301,127
Class K
Shares sold		348,229		$	5,361,096			103,655		$	1,663,652
Shares issued in reinvestment of distributions		18,491			296,673			12,891			180,399
Shares redeemed		(61,171	)		(932,877	)		(61,632	)		(991,964	)
Net increase		305,549		$	4,724,892			54,914		$	852,087
Class R
Shares sold		166,958		$	2,553,228			38,030		$	593,449
Shares issued in reinvestment of distributions		5,785			90,577			5,706			78,303
Shares redeemed		(105,917	)		(1,614,313	)		(26,846	)		(413,928	)
Net increase		66,826		$	1,029,492			16,890		$	257,824
Total Net Increase		430,103		$	6,591,286			77,679		$	1,104,216
	Period from 10/30/19 (a) to 12/31/19
LifePath Dynamic 2065 Fund	Shares			Amount
Institutional
Shares sold		40,001		$	400,010
Shares issued in reinvestment of distributions		—			—
Shares redeemed		(1	)		(10	)
Net increase		40,000		$	400,000
Investor A
Shares sold		40,001		$	400,010
Shares issued in reinvestment of distributions		—			—
Shares redeemed		(1	)		(10	)
Net increase		40,000		$	400,000
Investor C
Shares sold		40,001		$	400,010
Shares issued in reinvestment of distributions		—			—
Shares redeemed		(1	)		(10	)
Net increase		40,000		$	400,000
Class K
Shares sold		240,001		$	2,400,010
Shares issued in reinvestment of distributions		—			—
Shares redeemed		(1	)		(10	)
Net increase		240,000		$	2,400,000
Class R
Shares sold		40,001		$	400,010
Shares issued in reinvestment of distributions		—			—
Shares redeemed		(1	)		(10	)
Net increase		40,000		$	400,000
Total Net Increase		400,000		$	4,000,000

^(a)  Commencement of operations.

NOTESTO FINANCIAL STATEMENTS 53

Notes to Financial Statements  (continued)

As of December 31, 2019, shares of the LifePath Dynamic Funds owned by BlackRock HoldCo 2, Inc., an affiliate of the LifePath Dynamic Funds, were as follows:

	LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund
Institutional		—		—
Investor A		—		—
Investor C		—		—
Class K		2,003		2,001
Class R		—		2,000

As of December 31, 2019, shares of the LifePath Dynamic Funds owned by BlackRock Financial Management, Inc., an affiliate of the LifePath Dynamic Funds, were as follows:

	LifePath Dynamic 2065 Fund
Institutional		40,000
Investor A		40,000
Investor C		40,000
Class K		240,000
Class R		40,000

7. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the LifePath Dynamic Funds through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

54 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm BlackRock Funds III

To the Board of Trustees of

BlackRock Funds III and Shareholders of each of the five series listed in the table below

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities of each of the series listed in the table below (five of the series constituting BlackRock Funds III, hereafter collectively referred to as the “Funds”) as of December 31, 2019, the related statements of operations and of changes in net assets for each of the periods indicated in the table below, including the related notes, and the financial highlights for each of the periods indicated in the table below (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Funds as of December 31, 2019, the results of each of their operations, the changes in each of their net assets, and each of the financial highlights for each of the periods indicated in the table below, in conformity with accounting principles generally accepted in the United States of America.

Fund	Statement of operations	Statement of changes in net assets	Financial highlights
BlackRock LifePath® Dynamic 2025 Fund BlackRock LifePath® Dynamic 2035 Fund BlackRock LifePath® Dynamic 2045 Fund BlackRock LifePath® Dynamic 2055 Fund	For the year ended December 31, 2019	For the years ended December 31, 2019 and 2018	For the years ended December 31, 2019, 2018, 2017, 2016 and 2015
BlackRock LifePath® Dynamic 2065 Fund	For the period October 30, 2019 (commencement of operations) through December 31, 2019

Basis for Opinions

These financial statements are the responsibility of the Funds’ management. Our responsibility is to express an opinion on the Funds’ financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Funds in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolios. We believe that our audits provide a reasonable basis for our opinions.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

REPORTOF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM 55

Important Tax Information  (unaudited)

The following information is provided with respect to the ordinary income distributions paid during the taxable year ended December 31, 2019:

	Payable Date	LifePath Dynamic 2025 Fund			LifePath Dynamic 2035 Fund			LifePath Dynamic 2045 Fund			LifePath Dynamic 2055 Fund			LifePath Dynamic 2065 Fund
Qualified Dividend Income for Individuals(a)	Quarterly		34.81	%		58.53	%		79.55	%		85.78	%		82.83	%
Qualified Business Income(a)	Quarterly		2.17			5.55			8.61			9.09			—
Dividends Qualifying for the Dividend Received Deduction for Corporations(a)	Quarterly		10.81			17.57			22.75			24.93			16.89
Federal Obligation Interest(b)	Quarterly		5.27			4.65			4.39			4.25			0.74
Interest-Related Dividends and Qualified Short-Term Capital Gains for Non-U.S. Residents(c)	Quarterly		58.00			29.67			12.17			10.86			1.71

^(a)  The LifePath Dynamic Funds hereby designate the percentage indicated above or the maximum amount allowable by law.

^(b)  The law varies in each state as to whether and what percentage of dividend income attributable to federal obligations is exempt from state income tax. We recommend that you consult your tax advisor to determine if any portion of the dividends you received is exempt from state income taxes.

^(c)  Represents the portion of the taxable ordinary income dividends eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations.

Additionally, the LifePath Dynamic Funds distributed long-term capital gains per share to shareholders of record as follows:

	Record Date	LifePath Dynamic 2025 Fund		LifePath Dynamic 2035 Fund		LifePath Dynamic 2045 Fund		LifePath Dynamic 2055 Fund
Long-Term Capital Gains Per Share	12/30/2019	$	0.313971	$	0.415922	$	0.475882	$	0.455113

56 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Master Portfolio Information  as of December 31, 2019

LifePath^® Dynamic 2025 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		52	%
Fixed Income Funds		43
Short-Term Securities		12
Liabilities in Excess of Other Assets		(7	)

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		31	%
CoreAlpha Bond Master Portfolio		30
International Tilts Master Portfolio		8
iShares TIPS Bond ETF		7
Master Total Return Portfolio		6
BlackRock Advantage Emerging Markets Fund — Class K		5
BlackRock Tactical Opportunities Fund — Class K		3
iShares Developed Real Estate Index Fund — Class K		2
iShares MSCI EAFESmall-Cap ETF		2

LifePath^® Dynamic 2035 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		73	%
Fixed Income Funds		21
Short-Term Securities		12
Liabilities in Excess of Other Assets		(6	)

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		42	%
CoreAlpha Bond Master Portfolio		13
International Tilts Master Portfolio		13
BlackRock Advantage Emerging Markets Fund — Class K		8
iShares TIPS Bond ETF		5
iShares Developed Real Estate Index Fund — Class K		4
BlackRock Tactical Opportunities Fund — Class K		3
iShares MSCI EAFESmall-Cap ETF		3
Master Total Return Portfolio		2

LifePath^® Dynamic 2045 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		87	%
Short-Term Securities		11
Fixed Income Funds		4
Liabilities in Excess of Other Assets		(2	)

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		51	%
International Tilts Master Portfolio		17
BlackRock Advantage Emerging Markets Fund — Class K		10
iShares Developed Real Estate Index Fund — Class K		4
iShares MSCI EAFESmall-Cap ETF		4
CoreAlpha Bond Master Portfolio		2
iShares TIPS Bond ETF		1
BlackRock Tactical Opportunities Fund — Class K		1
Master Total Return Portfolio		1

The LifePath^® Dynamic Master Portfolios’ allocations and holdings listed above are current as of the report date. However, the LifePath^® Dynamic Master Portfolios are regularly monitored and their composition may vary throughout various periods.

MASTER PORTFOLIO INFORMATION 57

Master Portfolio Information  as of December 31, 2019(continued)

LifePath^® Dynamic 2055 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Net Assets
Equity Funds		89	%
Short-Term Securities		10
Fixed Income Funds		1

TEN LARGEST HOLDINGS

Holdings	Percent of Net Assets
Active Stock Master Portfolio		52	%
International Tilts Master Portfolio		18
BlackRock Advantage Emerging Markets Fund — Class K		10
iShares Developed Real Estate Index Fund — Class K		5
iShares MSCI EAFESmall-Cap ETF		4
CoreAlpha Bond Master Portfolio		1

LifePath^® Dynamic 2065 Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Total Net Assets
Equity Funds		94	%
Short-Term Securities		9
Fixed Income Funds		1
Liabilities in Excess of Other Assets		(4	)

TEN LARGEST HOLDINGS

Holdings	Percent of Total Net Assets
Active Stock Master Portfolio		52	%
International Tilts Master Portfolio		19
BlackRock Advantage Emerging Markets Fund — Class K		10
iShares Developed Real Estate Index Fund — Class K		5
iShares MSCI EAFESmall-Cap ETF		4
iShares MSCI Canada ETF		3
iShares Russell 2000 ETF		2
CoreAlpha Bond Master Portfolio		1

The LifePath^® Dynamic Master Portfolios’ allocations and holdings listed above are current as of the report date. However, the LifePath^® Dynamic Master Portfolios are regularly monitored and their composition may vary throughout various periods.

58 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 LifePath^® Dynamic 2025 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d) — 107.1%
Equity Funds — 51.8%
Active Stock Master Portfolio	$	21,308,306	$	21,308,306
BlackRock Advantage Emerging Markets Fund — Class K		324,716		3,542,655
BlackRock Tactical Opportunities Fund — Class K		161,827		2,173,336
International Tilts Master Portfolio	$	5,807,694		5,807,694
iShares Developed Real Estate Index Fund — Class K		157,568		1,730,092
iShares MSCI EAFESmall-Cap ETF(a)		22,178		1,381,246
				35,943,329
Fixed Income Funds — 43.3%
CoreAlpha Bond Master Portfolio	$	20,975,583		20,975,583
iShares TIPS Bond ETF		44,433		5,179,555
Master Total Return Portfolio	$	3,944,897		3,944,897
				30,100,035

Security	Shares/ Investment Value		Value
Short-Term Securities — 12.0%
BlackRock Cash Funds: Institutional,
SL Agency Shares, 1.87%(b)(c)	$	972,906	$	973,295
BlackRock Cash Funds: Treasury,
SL Agency Shares, 1.55%(b)		7,339,296		7,339,296
				8,312,591
Total Affiliated Investment Companies — 107.1% (Cost — $69,256,257)				74,355,955
Liabilities in Excess of Other Assets — (7.1) %				(4,932,786	)
Net Assets — 100.0%			$	69,423,169

^(a)  Security, or a portion of the security, is on loan.

^(b)  Annualized7-day yield as of period end.

^(c)  All portion of the security was purchased with the cash collateral from loaned securities.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased		Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio(b)	$	13,605,797	$	7,702,509	$	—		$	21,308,306	$	21,308,306	$	311,616		$	1,681,222		$	3,010,406
BlackRock Advantage Emerging Markets Fund — Class K		223,206		168,306		(66,796	)		324,716		3,542,655		80,960			(41,795	)		454,136
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		951,508		21,398		—			972,906		973,295		3,370	(c)		393			—
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		1,351,614		5,987,682		—			7,339,296		7,339,296		56,572			—			—
BlackRock Tactical Opportunities Fund — Class K		105,669		76,152		(19,994	)		161,827		2,173,336		71,081			(283	)		(40,493	)
CoreAlpha Bond Master Portfolio(b)	$	13,093,963	$	7,881,620	$	—		$	20,975,583		20,975,583		481,149			333,707			(253,642	)
International Tilts Master Portfolio(b)	$	4,077,323	$	1,730,371	$	—		$	5,807,694		5,807,694		170,723			150,818			1,305,468
iShares Developed Real Estate Index Fund — Class K		—		195,284		(37,716	)		157,568		1,730,092		73,751			(772	)		(38,892	)
iShares Edge MSCI Multifactor International ETF(d)		35,488		7,882		(43,370	)		—		—		16,739			109,108			(37,132	)
iShares Edge MSCI Multifactor USA ETF(d)		17,069		15,710		(32,779	)		—		—		8,034			90,615			(22,379	)
iShares International Developed Real Estate ETF(d)		—		12,690		(12,690	)		—		—		2,056			(2,306	)		—
iShares MSCI EAFESmall-Cap ETF		17,282		5,713		(817	)		22,178		1,381,246		46,113			(4,280	)		215,555
iShares TIPS Bond ETF		23,792		24,643		(4,002	)		44,433		5,179,555		68,623			5,327			208,431
iShares U.S. Real Estate ETF(d)		—		6,737		(6,737	)		—		—		—			(605	)		—
Master Total Return Portfolio(b)	$	2,398,817	$	1,546,080	$	—		$	3,944,897		3,944,897		143,280			96,452			169,859
										$	74,355,955	$	1,534,067		$	2,417,601		$	4,971,317

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/investment value purchased (sold).

^(c)  Represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

SCHEDULES OF INVESTMENTS 59

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2025 Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		6		03/19/20	$	936	$	4,486
E-Mini MSCI EAFE Index		21		03/20/20		2,138		56,946
Russell 2000E-Mini Index		26		03/20/20		2,172		44,678
S&P 500E-Mini Index		3		03/20/20		485		13,856
								119,966
Short Contracts
U.S. Treasury Ultra Bond		4		03/20/20		727		23,368
							$	143,334

Forward Foreign Currency Exchange Contracts
Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	977,113	USD	737,140	Morgan Stanley & Co. International PLC		03/18/20	$	15,525
EUR	300,000	USD	334,702	Bank of America N.A.		03/18/20		3,389
EUR	3,136,903	USD	3,495,984	Bank of America N.A.		03/18/20		39,206
	Net unrealized appreciation							58,120

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Future contracts
Unrealized appreciation on future contracts(a)	$	—	$	—	$	119,966	$	—	$	23,368	$	—	$	143,334
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		58,120		—		—		58,120
	$	—	$	—	$	119,966	$	58,120	$	23,368	$—		$	201,454

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

60 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2025 Master Portfolio

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	677,639	$	—		$	(23,220)	$	—	$	654,419
Forward foreign currency exchange contracts		—		—		—		(174,870	)		—		—		(174,870	)
	$	—	$	—	$	677,639	$	(174,870)		$	(23,220)	$	—	$	479,549
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	322,312	$	—		$	14,815	$	—	$	337,127
Forward foreign currency exchange contracts		—		—		—		102,158			—		—		102,158
	$	—	$	—	$	322,312	$	102,158		$	14,815	$	—	$	439,285

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	6,039,458
Average notional value of contracts — short	$	1,696,930
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	1,360,564
Average amounts sold — in USD	$	5,179,923

For more information about the LifePath Dynamic Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	19,350		$	1,571
Forward foreign currency exchange contracts		58,120			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	77,470		$	1,571
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(19,350	)		(1,571	)
Total derivative assets and liabilities subject to an MNA	$	58,120		$	—

The following table presents the LifePath Dynamic Master Portfolio’s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets (a)(b)
Bank of America N.A.	$	42,595	$	—	$	—	$	—	$	42,595
Morgan Stanley & Co. International PLC		15,525		—		—		—		15,525
	$	58,120	$	—	$	—	$	—	$	58,120

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

SCHEDULES OF INVESTMENTS 61

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2025 Master Portfolio

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investment Companies
Equity Funds	$	8,827,329	$	—	$	—	$	8,827,329
Fixed Income Funds		5,179,555		—		—		5,179,555
Short-Term Securities		8,312,591		—		—		8,312,591
Subtotal	$	22,319,475	$	—	$	—	$	22,319,475
Investments Valued at NAV(a)								52,036,480
Total Investments							$	74,355,955
Derivative Financial Instruments (b)
Assets:
Equity contracts	$	119,966	$	—	$	—	$	119,966
Forward foreign currency contracts		—		58,120		—		58,120
Interest rate contracts		23,368		—		—		23,368
	$	143,334	$	58,120	$	—	$	201,454

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(a)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

62 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments   December 31, 2019 LifePath^® Dynamic 2035 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d) — 105.6%
Equity Funds — 72.9%
Active Stock Master Portfolio	$	29,282,918	$	29,282,918
BlackRock Advantage Emerging Markets Fund — Class K		495,913		5,410,406
BlackRock Tactical Opportunities Fund — Class K		157,464		2,114,741
International Tilts Master Portfolio		9,205,092		9,205,092
iShares Developed Real Estate Index Fund — Class K		226,151		2,483,142
iShares MSCI EAFESmall-Cap ETF(a)		33,451		2,083,328
				50,579,627
Fixed Income Funds — 20.5%
CoreAlpha Bond Master Portfolio		9,219,168		9,219,168
iShares TIPS Bond ETF(a)		28,542		3,327,141
Master Total Return Portfolio		1,698,948		1,698,948
				14,245,257

Security	Shares/ Investment Value		Value
Short-Term Securities — 12.2%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(b)(c)	$	2,150,636	$	2,151,497
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(c)		6,296,905		6,296,905
				8,448,402
Total Affiliated Investment Companies — 105.6% (Cost — $67,208,366)				73,273,286
Liabilities in Excess of Other Assets — (5.6)%				(3,890,929	)
Net Assets — 100.0%			$	69,382,357

^(a) Security, or a portion of the security, is on loan.

^(b)  All or a portion of security was purchased with the cash collateral from loaned securities.

^(c) Annualized7-day yield as of period end.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased		Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio(b)	$	17,201,161	$	12,081,757	$	—		$	29,282,918	$	29,282,918	$	396,428		$	1,914,221		$	3,700,668
BlackRock Advantage Emerging Markets Fund-Class K		288,485		302,075		(94,647	)		495,913		5,410,406		121,761			(63,131	)		642,278
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		1,249,787		900,849		—			2,150,636		2,151,497		4,770	(c)		544			(2	)
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		467,926		5,828,979		—			6,296,905		6,296,905		40,504			—			—
BlackRock Tactical Opportunities Fund-Class K		102,371		60,735		(5,642	)		157,464		2,114,741		68,072			1,489			(37,924	)
CoreAlpha Bond Master Portfolio(b)	$	5,494,666	$	3,724,502	$	—		$	9,219,168		9,219,168		196,282			139,521			(224,024	)
International Tilts Master Portfolio(b)	$	5,050,546	$	4,154,546	$	—		$	9,205,092		9,205,092		209,020			194,543			1,479,774
iShares Developed Real Estate Index Fund-Class K		—		324,930		(98,779	)		226,151		2,483,142		106,290			(239	)		(54,575	)
iShares Edge MSCI Multifactor International ETF(d)		48,587		2,048		(50,635	)		—		—		20,136			114,833			(21,360	)
iShares Edge MSCI Multifactor USA ETF(d)		29,879		3,411		(33,290	)		—		—		10,959			172,049			(45,389	)
iShares International Developed Real Estate ETF(d)		—		21,494		(21,494	)		—		—		3,582			(3,698	)		—
iShares MSCI Canada ETF(d)		1,178		—		(1,178	)		—		—		—			(607	)		4,244
iShares MSCI EAFESmall-Cap ETF		24,627		13,777		(4,953	)		33,451		2,083,328		65,577			(31,760	)		331,220
iShares TIPS Bond ETF		10,594		20,262		(2,314	)		28,542		3,327,141		37,069			2,768			95,500
iShares U.S. Real Estate ETF(d)		—		11,285		(11,285	)		—		—		—			(1,013	)		—
Master Total Return Portfolio(b)	$	1,266,978	$	431,970	$	—		$	1,698,948		1,698,948		64,695			45,336			148,184
										$	73,273,286	$	1,345,145		$	2,484,856		$	6,018,594

^(a) Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/investment value purchased (sold).

^(c)  Represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

SCHEDULES OF INVESTMENTS 63

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2035 Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		9		03/19/20	$	1,403	$	6,729
E-Mini MSCI EAFE Index		30		03/20/20		3,055		73,201
Russell 2000E-Mini Index		20		03/20/20		1,671		34,367
S&P 500E-Mini Index		3		03/20/20		485		13,856
								128,153
Short Contracts
10-Year U.S. Treasury Note		10		03/20/20		1,284		11,158
U.S. Treasury Ultra Bond		4		03/20/20		727		23,368
								34,526
							$	162,679

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	1,628,104	USD	1,228,252	Morgan Stanley & Co. International PLC		03/18/20	$	25,869
EUR	350,000	USD	390,485	Bank of America N.A.		03/18/20		3,954
EUR	3,006,703	USD	3,350,880	Bank of America N.A.		03/18/20		37,578
Net unrealized appreciation							$	67,401

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	128,153	$	—	$	34,526	$	—	$	162,679
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		67,401		—		—		67,401
	$	—	$	—	$	128,153	$	67,401	$	34,526	$	—	$	230,080

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

64 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2035 Master Portfolio

Derivative Financial Instruments Categorized by Risk Exposure (continued)

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	624,333	$	—		$	36,746	$	—	$	661,079
Forward foreign currency exchange contracts		—		—		—		(166,778	)		—				(166,778	)
	$	—	$	—	$	624,333	$	(166,778	)	$	36,746	$	—	$	494,301
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	295,717	$	—		$	11,718	$	—	$	307,435
Forward foreign currency exchange contracts		—		—		—		119,883			—		—		119,883
	$	—	$	—	$	295,717	$	119,883		$	11,718	$	—	$	427,318

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	6,519,532
Average notional value of contracts — short	$	2,022,672
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	1,566,332
Average amounts sold — in USD	$	5,307,980

For more information about the Fund’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	22,828		$	2,356
Forward foreign currency exchange contracts		67,401			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	90,229		$	2,356
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(22,828	)		(2,356	)
Total derivative assets and liabilities subject to an MNA	$	67,401		$	—

The following table presents the Lifepath Dynamic Master Portfolio derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the Lifepath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)(b)
Bank of America N.A.	$	41,532	$	—	$	—	$	—	$	41,532
Morgan Stanley & Co. International PLC		25,869		—		—		—		25,869
	$	67,401	$	—	$	—	$	—	$	67,401

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

SCHEDULES OF INVESTMENTS 65

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2035 Master Portfolio

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the Lifepath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the Lifepath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investment Companies:
Equity Funds	$	12,091,617	$	—	$	—	$	12,091,617
Fixed Income Fund		3,327,141		—		—		3,327,141
Short-Term Securities		8,448,402		—		—		8,448,402
Subtotal	$	23,867,160	$	—	$	—	$	23,867,160
Investments Valued at NAV(a)								49,406,126
Total Investments							$	73,273,286
Derivative Financial Instruments (b)
Assets:
Forward foreign currency contracts	$	—	$	67,401	$	—	$	67,401
Interest rate contracts		34,526		—		—		34,526
Equity contracts		128,153		—		—		128,153
	$	162,679	$	67,401	$	—	$	230,080

^(a)  Certain investments of the Lifepath Dynamic Master were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b) Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

66 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 LifePath^® Dynamic 2045 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d)— 101.2%
Equity Funds — 86.7%
Active Stock Master Portfolio	$	25,529,263	$	25,529,263
BlackRock Advantage Emerging Markets Fund — Class K		453,125		4,943,591
BlackRock Tactical Opportunities Fund — Class K		37,764		507,176
Master Total Return Portfolio	$	19,004		253,365
International Tilts Master Portfolio	$	8,495,927		8,495,927
iShares Developed Real Estate Index Fund — Class K		199,993		2,195,928
iShares MSCI EAFESmall-Cap ETF(a)		29,904		1,862,421
				43,787,671
Fixed Income Funds — 3.9%
CoreAlpha Bond Master Portfolio	$	1,237,147		1,237,147
iShares TIPS Bond ETF(a)		6,170		719,237
				1,956,384

Security	Shares/ Investment Value		Value
Short-Term Securities — 10.6%
BlackRock Cash Funds: Institutional, SL Agency Shares, 1.87%(b)(c)	$	138,315	$	138,370
BlackRock Cash Funds: Treasury, SL Agency Shares, 1.55%(b)		5,240,686		5,240,686
				5,379,056
Total Affiliated Investment Companies — 101.2% (Cost — $46,044,244)				51,123,111
Liabilities in Excess of Other Assets — (1.2)%				(620,878	)
Net Assets — 100.0%			$	50,502,233

^(a)  Security, or a portion of the security, is on loan.

^(b)  Annualized7-day yield as of period end.

^(c)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased		Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio(b)	$	14,311,152	$	11,218,111	$	—		$	25,529,263	$	25,529,263	$	325,958		$	1,467,849		$	2,883,748
BlackRock Advantage Emerging Markets Fund — Class K(b)		245,996		270,535		(63,406	)		453,125		4,943,591		109,191			(36,695	)		550,691
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		455,840		—		(317,525	)		138,315		138,370		3,221	(c)		299			—
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		81,017		5,159,669		—			5,240,686		5,240,686		55,010			—			—
BlackRock Tactical Opportunities Fund — Class K		23,768		13,997		(1	)		37,764		507,176		14,681			—			(7,496	)
Master Total Return Portfolio(b)	$	—	$	19,004	$	—		$	19,004		253,365		1			—			—
CoreAlpha Bond Master Portfolio(b)	$	1,010,090	$	227,057	$	—		$	1,237,147		1,237,147		37,167			39,300			53,996
International Tilts Master Portfolio(b)	$	4,608,540	$	3,887,387	$	—		$	8,495,927		8,495,927		184,047			198,833			1,356,846
iShares Developed Real Estate Index Fund — Class K		—		293,578		(93,585	)		199,993		2,195,928		94,464			(851	)		(47,945	)
iShares Edge MSCI Multifactor International ETF		31,238		3,481		(34,719	)		—		—		17,221			92,495			(32,684	)
iShares Edge MSCI Multifactor USA ETF(d)		40,433		4,726		(45,159	)		—		—		11,780			203,877			(45,050	)
iShares International Developed Real Estate ETF(d)		—		19,540		(19,540	)		—		—		3,376			(3,197	)		—
iShares MSCI EAFESmall-Cap ETF		17,813		17,186		(5,095	)		29,904		1,862,421		55,105			(597	)		251,337
iShares TIPS Bond ETF		1,192		5,394		(416	)		6,170		719,237		6,322			6			12,733
iShares U.S. Real Estate ETF		—		10,106		(10,106	)		—		—		—			(907	)		—
										$	51,123,111	$	917,544		$	1,960,412		$	4,976,176

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/investment value purchased (sold).

^(c)  Represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

SCHEDULES OF INVESTMENTS 67

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2045 Master Portfolio

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value / Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		8		03/19/20	$	1,247	$	5,981
E-Mini MSCI EAFE Index		26		03/20/20		2,647		65,071
Russell 2000E-Mini Index		12		03/20/20		1,002		20,620
S&P 500E-Mini Index		2		03/20/20		323		9,238
								100,910
Short Contracts
10-Year U.S. Treasury Note		13		03/20/20		1,669		14,137
U.S. Treasury Ultra Bond		3		03/20/20		545		17,526
								31,663
							$	132,573

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	1,474,637	USD	1,112,476	Morgan Stanley & Co. International PLC		03/18/20	$	23,431
EUR	39,071	USD	43,543	Bank of America N.A.		03/18/20		488
EUR	200,000	USD	223,134	Bank of America N.A.		03/18/20		2,259
EUR	2,171,104	USD	2,419,782	Bank of America N.A.		03/18/20		26,983
Net unrealized appreciation							$	53,161

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	100,910	$	—	$	31,663	$	—	$	132,573
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		53,161		—		—		53,161
	$	—	$	—	$	100,910	$	53,161	$	31,663	$	—	$	185,734

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts			Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	408,352	$	—		$	(17,017	)	$	—	$	391,335
Forward foreign currency exchange contracts		—		—		—		(118,657	)		—			—		(118,657	)
	$	—	$	—	$	408,352	$	(118,657	)	$	(17,017	)	$	—	$	272,678
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	168,245	$	—		$	31,663		$	—	$	199,908
Forward foreign currency exchange contracts		—		—		—		93,589			—			—	$	93,589
	$	—	$	—	$	177,328	$	93,589		$	31,663		$	—	$	293,497

68 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2045 Master Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	4,400,866
Average notional value of contracts — short	$	1,865,613
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	1,310,057
Average amounts sold — in USD	$	4,022,513

For more information about the LifePath Dynamic Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	19,210		$	2,095
Forward foreign currency exchange contracts		53,161			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	72,371		$	2,095
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(19,210	)		(2,095	)
Total derivative assets and liabilities subject to an MNA	$	53,161		$	—

The following table presents the LifePath Dynamic Master Portfolio’s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)(b)
Bank of America N.A.	$	29,730	$	—	$	—	$	—	$	29,730
Morgan Stanley & Co. International PLC		23,431		—		—		—		23,431
	$	53,161	$	—	$	—	$	—	$	53,161

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investments Companies
Equity Funds	$	9,762,481	$	—	$	—	$	9,762,481
Fixed Income Funds		719,237		—		—		719,237
Short-Term Securities		5,379,056		—		—		5,379,056
Subtotal	$	15,860,774	$	—	$	—	$	15,860,774
Investments Valued at NAV(a)								35,262,337
Total Investments							$	51,123,111
Derivative Financial Instruments (b)
Assets:
Equity contracts	$	100,910	$	—	$	—	$	100,910
Forward foreign currency contracts		—		53,161		—		53,161
Interest rate contracts		31,663		—		—		31,663
	$	132,573	$	53,161	$	—	$	185,734

^(a)  Certain investments of the LifePath Dynamic Master were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

SCHEDULES OF INVESTMENTS 69

Schedule of Investments December 31, 2019 LifePath^® Dynamic 2055 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d)— 100.1%
Equity Funds — 89.2%
Active Stock Master Portfolio	$	14,405,876	$	14,405,876
BlackRock Advantage Emerging Markets Fund — Class K		260,340		2,840,312
Master Total Return Portfolio	$	10		133
International Tilts Master Portfolio	$	4,957,218		4,957,218
iShares Developed Real Estate Index Fund — Class K		114,152		1,253,383
iShares MSCI EAFESmall-Cap ETF(a)		16,909		1,053,093
				24,510,015
Fixed Income Funds — 1.0%
CoreAlpha Bond Master Portfolio	$	241,841		241,841
iShares TIPS Bond ETF		331		38,584
				280,425

Security	Shares/ Investment Value		Value
Short-Term Securities — 9.9%
BlackRock Cash Funds: Institutional, SL Agency Shares, 1.87%(b)(c)	$	6,266	$	6,268
BlackRock Cash Funds: Treasury, SL Agency Shares, 1.55%(c)		2,710,144		2,710,144
				2,716,412
Total Affiliated Investment Companies — 100.1% (Cost — $24,746,580)				27,506,852
Liabilities in Excess of Other Assets — (0.1)%				(14,800	)
Net Assets — 100.0%			$	27,492,052

^(a)  Security, or a portion of the security, is on loan.

^(b)  Annualized7-day yield as of period end.

^(c)  All or a portion of security was purchased with the cash collateral from loaned securities.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased			Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio(b)	$	7,607,800	$	6,798,076		$	—		$	14,405,876	$	14,405,876	$	189,807		$	766,642		$	1,625,430
BlackRock Advantage Emerging Markets Fund — Class K		149,850		148,171			(37,681	)		260,340		2,840,312		63,204			(23,607	)		315,006
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		129,439		—			(123,173	)		6,266		6,268		2,127	(c)		299			—
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		344,109		2,366,035	(b)		—			2,710,144		2,710,144		41,246			—			—
Master Total Return Portfolio(b)	$	—	$	10		$	—		$	10		133		1			—			—
CoreAlpha Bond Master Portfolio(b)	$	195,395	$	46,446		$	—		$	241,841		241,841		6,599			4,573			15,680
International Tilts Master Portfolio(b)	$	2,731,807	$	2,225,411		$	—		$	4,957,218		4,957,218		111,553			106,132			783,397
iShares Developed Real Estate Index Fund — Class K		—		179,111			(64,959	)		114,152		1,253,383		54,116			(541	)		(26,274	)
iShares Edge MSCI Multifactor International ETF(d)		18,468		813			(19,281	)		—		—		10,181			53,428			(19,323	)
iShares Edge MSCI Multifactor USA ETF(d)		33,447		2,601			(36,048	)		—		—		13,987			196,932			(59,418	)
iShares International Developed Real Estate ETF(d)		—		13,908			(13,908	)		—		—		2,495			—			—
iShares MSCI Canada ETF(d)		4,986		1,249			(6,235	)		—		—		1,262			2,879			20,750
iShares MSCI EAFESmall-Cap ETF		12,729		9,338			(5,158	)		16,909		1,053,093		33,759			(17,224	)		174,557
iShares TIPS Bond ETF		—		331			—			331		38,584		381			—			392
											$	27,506,852	$	530,718		$	1,089,513		$	2,830,197

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/investment value purchased (sold).

^(c)  Represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

^(d)  As of period end, the entity is no longer held by the LifePath Dynamic Master Portfolio.

70 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2055 Master Portfolio (Percentages shown are based on Net Assets)

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts:
S&P/TSX 60 Index		5		03/19/20	$	780	$	3,738
E-Mini MSCI EAFE Index		14		03/20/20		1,426		35,247
Russell 2000E-Mini Index		7		03/20/20		585		12,029
							$	51,014

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
CAD	981,493	USD	740,445	Morgan Stanley & Co. International PLC		03/18/20	$	15,595
EUR	30,135	USD	33,585	Bank of America N.A.		03/18/20		377
EUR	100,000	USD	111,567	Bank of America N.A.		03/18/20		1,129
EUR	1,193,528	USD	1,330,220	Morgan Stanley & Co. International PLC		03/18/20		14,848
Net unrealized appreciation							$	31,949

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on future contracts(a)	$	—	$	—	$	51,014	$	—	$	—	$	—	$	51,014
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		31,949		—		—		31,949
	$	—	$	—	$	51,014	$	31,949	$	—	$	—	$	82,963

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, as reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in the accumulated earnings (loss).

For year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Net Realized Gain(Loss) from:
Futures contracts	$	—	$	—	$	155,681	$	—		$	—	$	—	$	155,681
Forward foreign currency exchange contracts		—		—		—		(69,417	)		—		—		(69,417	)
	$	—	$	—	$	155,681	$	(69,417	)	$	—	$	—	$	86,264
Net Change in Unrealized Appreciation(Depreciation) on:
Futures contracts	$	—	$	—	$	70,085	$	—		$	—	$	—	$	70,085
Forward foreign currency exchange contracts		—		—		—		50,008			—		—		50,008
	$	—	$	—	$	70,085	$	50,008		$	—	$	—	$	120,093

SCHEDULES OF INVESTMENTS 71

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2055 Master Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	1,988,170
Average notional value of contracts — Short	$	—	(a)
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	770,898
Average amounts sold — in USD	$	2,336,789

^(a)  Derivative not held atquarter-end. The risk exposure table serves as an indicator of activity during the period.

For more information about the Lifepath Dynamic Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to financial statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	7,394		$	1,309
Forward foreign currency exchange contracts		31,949			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	39,343		$	1,309
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(7,394	)		(1,309	)
Total derivative assets and liabilities subject to an MNA	$	31,949		$	—

The following table presents the LifePath Dynamic Master Portfolio’s derivative assets by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)(b)
Bank of America N.A.	$	1,506	$	—	$	—	$	—	$	1,506
Morgan Stanley & Co. International PLC		30,443		—		—		—		30,443
	$	31,949	$	—	$	—	$	—	$	31,949

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

^(b)  Net amount may also include forward foreign currency exchange contracts that are not required to be collateralized.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Equity Funds	$	5,146,788	$	—	$	—	$	5,146,788
Fixed Income Fund		38,584		—		—		38,584
Short-Term Securities		2,716,412		—		—		2,716,412
Subtotal	$	7,901,784	$	—	$	—	$	7,901,784
Investments Valued at NAV(a)								19,605,068
							$	27,506,852
Derivative Financial Instruments(b)
Assets:
Equity contracts	$	51,014	$	—	$	—	$	51,014
Forward foreign currency contracts		—		31,949		—		31,949
	$	51,014	$	31,949	$	—	$	82,963

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

72 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 LifePath^® Dynamic 2065 Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares/ Investment Value		Value
Affiliated Investment Companies(d) — 104.3%
Equity Funds — 94.2%
Active Stock Master Portfolio	$	2,195,914	$	2,195,914
BlackRock Advantage Emerging Markets Fund — Class K		39,679		432,899
Master Total Return Portfolio	$	152		2,021
International Tilts Master Portfolio	$	782,737		782,737
iShares Developed Real Estate Index Fund — Class K		18,113		198,885
iShares MSCI Canada ETF(a)		3,688		110,234
iShares MSCI EAFESmall-Cap ETF(a)		2,687		167,346
iShares Russell 2000 ETF(a)		512		84,823
				3,974,859
Fixed Income Funds — 0.9%
CoreAlpha Bond Master Portfolio	$	35,338		35,338
iShares TIPS Bond ETF		35		4,080
				39,418

Security	Shares/ Investment Value		Value
Short-Term Securities — 9.2%
BlackRock Cash Funds: Institutional, SL Agency Shares, 1.87%(b)(c)	$	231,843	$	231,936
BlackRock Cash Funds: Treasury, SL Agency Shares, 1.55%(b)		153,506		153,506
				385,442
Total Affiliated Investment Companies — 104.3% (Cost — $4,215,593)				4,399,719
Liabilities in Excess of Other Assets — (4.3)%				(181,416	)
Net Assets — 100.0%			$	4,218,303

^(a)  Security, or a portion of the security, is on loan.

^(b)  Annualized7-day yield as of period end.

^(c)  Security was purchased with the cash collateral from loaned securities.

^(d)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the LifePath Dynamic Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the LifePath Dynamic Master Portfolio were as follows:

Affiliate Persons and/or Related Parties	Shares/ Investment Value Held at 12/31/18		Shares/ Investment Value Purchased		Shares/ Investment Value Sold			Shares/ Investment Value Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
Active Stock Master Portfolio(b)	$	—	$	2,195,914	$	—		$	2,195,914	$	2,195,914	$	7,027		$	(8,278	)	$	128,640
BlackRock Advantage Emerging Markets Fund — Class K		—		45,142		(5,463	)		39,679		432,899		9,562			801			18,665
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		—		231,843		—			231,843		231,936		32	(c)		—			—
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		—		153,506		—			153,506		153,506		550			—			—
Master Total Return Portfolio(b)	$	—	$	152	$	—		$	152		2,021		15			—			22
CoreAlpha Bond Master Portfolio(b)	$	—	$	35,338	$	—		$	35,338		35,338		164			(349	)		(755	)
International Tilts Master Portfolio(b)	$	—	$	782,737	$	—		$	782,737		782,737		2,551			2,914			30,378
iShares Developed Real Estate Index Fund — Class K		—		18,113		—			18,113		198,885		7,253			—			(8,226	)
iShares MSCI Canada ETF		—		3,688		—			3,688		110,234		1,385			—			3,773
iShares MSCI EAFESmall-Cap ETF		—		2,687		—			2,687		167,346		3,378			—			6,818
iShares Russell 2000 ETF		—		512		—			512		84,823		306			—			4,781
iShares TIPS Bond ETF		—		35		—			35		4,080		8			—			30
										$	4,399,719	$	32,231		$	(4,912	)	$	184,126

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares/investment value purchased (sold).

^(c)  Represents all or a portion of securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
E-Mini MSCI EAFE Index		2		03/20/20	$	204	$	5,423

SCHEDULES OF INVESTMENTS 73

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2065 Master Portfolio

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized Appreciation (Depreciation)
EUR	192,500	USD	214,535	Bank of America N.A.		03/18/20	$	2,406
Net unrealized appreciation							$	2,406

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on future contracts(a)	$	—	$	—	$	5,423	$	—	$	—	$	—	$	5,423
Forward foreign currency exchange contracts
Unrealized appreciation on forward foreign currency exchange contracts		—		—		—		2,406		—		—		2,406
	$	—	$	—	$	5,423	$	2,406	$	—	$	—	$	7,829

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, if any, as reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in the accumulated earnings (loss).

For period ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	1,759	$	—		$	—	$	—	$	1,759
Forward foreign currency exchange contracts		—		—		—		(1,941	)		—		—		(1,941	)
	$	—	$	—	$	1,759	$	(1,941	)	$	—	$	—	$	(182	)
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	5,423	$	—		$	—	$	—	$	5,423
Forward foreign currency exchange contracts		—		—		—		2,406			—		—		2,406
	$	—	$	—	$	5,423	$	2,406		$	—	$	—	$	7,829

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	203,650
Forward foreign currency exchange contracts:
Average amounts purchased — in USD	$	—	(a)
Average amounts sold — in USD	$	214,535

^(a)  Derivative not held at anyquarter-end. The risk exposure table serves as an indicator of activity during the period.

For more information about the Lifepath Dynamic Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to financial statements.

Derivative Financial Instruments — Offsetting as of Period End

The Fund’s derivative assets and liabilities (by type) were as follows:

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	1,020		$	—
Forward foreign currency exchange contracts		2,406			—
Total derivative assets and liabilities in the Statements of Assets and Liabilities	$	3,426		$	—
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(1,020	)		—
Total derivative assets and liabilities subject to an MNA	$	2,406		$	—

74 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 LifePath^® Dynamic 2065 Master Portfolio

The following table presents the Fund’s derivative assets (and liabilities) by counterparty net of amounts available for offset under an MNA and net of the related collateral received by the LifePath Dynamic Master Portfolio:

Counterparty	Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset		Non-cash Collateral Received		Cash Collateral Received		Net Amount of Derivative Assets  (a)
Bank of America N.A.	$	2,406	$	—	$	—	$	—	$	2,406

^(a)  Net amount represents the net amount receivable from the counterparty in the event of default.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the LifePath Dynamic Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the LifePath Dynamic Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Affiliated Investment Companies
Equity Funds	$	996,208	$	—	$	—	$	996,208
Fixed Income Funds		4,080		—		—		4,080
Short-Term Securities		385,442		—		—		385,442
Subtotal	$	1,385,730	$	—	$	—	$	1,385,730
Investments Valued at NAV(a)								3,013,989
Total Investments							$	4,399,719
Derivative Financial Instruments(b)
Assets:
Equity contracts	$	5,423	$	—	$	—	$	5,423
Forward foreign currency contracts		—		2,406		—		2,406
	$	5,423	$	2,406	$	—	$	7,829

^(a)  Certain investments of the LifePath Dynamic Master Portfolio were fair valued using NAV per share or its equivalent as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

^(b)  Derivative financial instruments are futures contracts and forward foreign currency exchange contracts. Futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

SCHEDULES OF INVESTMENTS 75

Statements of Assets and Liabilities

December 31, 2019

	LifePath Dynamic 2025 Master Portfolio		LifePath Dynamic 2035 Master Portfolio		LifePath Dynamic 2045 Master Portfolio		LifePath Dynamic 2055 Master Portfolio		LifePath Dynamic 2065 Master Portfolio
ASSETS
Investments at value — affiliated(a)(b)	$	74,355,955	$	73,273,286	$	51,123,111	$	27,506,852	$	4,399,719
Cash pledged for futures contracts		245,000		282,000		232,000		109,000		10,000
Foreign currency at value(c)		104,847		133,342		125,091		58,875		—
Receivables:
Investments sold		303,101		210,653		176,765		110,473		46,890
Securities lending income — affiliated		257		564		425		104		32
Interest — affiliated		8,149		6,323		5,825		3,325		262
From the Manager		4,110		4,107		4,061		4,028		17,213
Variation margin on futures contracts		19,350		22,828		19,210		7,394		1,020
Unrealized appreciation on forward foreign currency exchange contracts		58,120		67,401		53,161		31,949		2,406
Total assets		75,098,889		74,000,504		51,739,649		27,832,000		4,477,542
LIABILITIES
Cash collateral on securities loaned at value		973,295		2,151,551		138,429		6,325		231,936
Payables:
Investments purchased		1,743,884		1,431,152		930,758		82,832		9,297
Investment advisory fees		5,049		4,977		3,512		1,926		318
Trustees’ and Officer’s fees		2,292		2,275		2,215		2,172		—
Professional fees		15,404		15,393		15,366		15,338		17,688
Variation margin on futures contracts		1,571		2,356		2,095		1,309		—
Withdrawals to investors		2,934,225		1,010,443		145,041		230,046		—
Total liabilities		5,675,720		4,618,147		1,237,416		339,948		259,239
NET ASSETS	$	69,423,169	$	69,382,357	$	50,502,233	$	27,492,052	$	4,218,303
NET ASSETS CONSIST OF
Investors’ capital	$	64,120,172	$	63,085,165	$	45,235,467	$	24,647,804	$	4,026,348
Net unrealized appreciation		5,302,997		6,297,192		5,266,766		2,844,248		191,955
NET ASSETS	$	69,423,169	$	69,382,357	$	50,502,233	$	27,492,052	$	4,218,303
(a) Investments at cost — affiliated	$	69,256,257	$	67,208,366	$	46,044,244	$	24,746,580	$	4,215,593
(b) Securities loaned at value	$	959,112	$	2,118,299	$	136,217	$	6,228	$	227,534
(c) Foreign currency at cost	$	103,077	$	131,316	$	123,079	$	57,961	$	—

See notes to financial statements.

76 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Operations

Year Ended December 31, 2019

	LifePath Dynamic 2025 Master Portfolio			LifePath Dynamic 2035 Master Portfolio			LifePath Dynamic 2045 Master Portfolio			LifePath Dynamic 2055 Master Portfolio			LifePath Dynamic 2065 Master Portfolio (a)
INVESTMENT INCOME
Dividends — affiliated	$	423,929		$	473,950		$	367,151		$	220,632		$	22,442
Dividends — unaffiliated		31,435			55,821			53,204			32,562			6
Securities lending income — affiliated — net		3,370			4,770			3,221			2,127			32
Foreign taxes withheld		(3,009	)		(5,867	)		(5,739	)		(3,299	)		—
Net investment income allocated from the applicable Underlying Master Portfolios:
Dividends — affiliated		500,811			618,040			518,789			306,413			9,853
Interest — affiliated		694,723			329,430			87,393			34,966			1,038
Expenses		(136,004	)		(135,142	)		(102,280	)		(58,264	)		(1,960	)
Fees waived		47,238			54,097			43,270			24,844			826
Total investment income		1,562,493			1,395,099			965,009			559,981			32,237
EXPENSES
Investment advisory		202,091			188,610			132,207			77,852			2,438
Trustees and Officer		11,581			11,489			11,214			10,999			1,865
Professional		15,441			15,438			15,386			15,355			15,631
Total expenses		229,113			215,537			158,807			104,206			19,934
Less fees waived and/or reimbursed by the Manager		(202,242	)		(190,513	)		(141,379	)		(94,495	)		(19,609	)
Total expenses after fees waived and/or reimbursed		26,871			25,024			17,428			9,711			325
Net investment income		1,535,622			1,370,075			947,581			550,270			31,912
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Allocation from the applicable Underlying Master Portfolios from investments, futures contracts, forward foreign currency exchange contracts and foreign currency transactions		2,262,199			2,293,621			1,705,982			877,347			(5,714	)
Futures contracts		654,419			661,079			391,335			155,681			1,759
Forward foreign currency exchange contracts		(174,870	)		(166,778	)		(118,657	)		(69,417	)		(1,941	)
Foreign currency transactions		(292	)		(642	)		(503	)		(820	)		—
Investments — affiliated		155,402			191,235			254,430			212,166			802
Investments — unaffiliated		370,988			708,101			687,166			409,419			—
		3,267,846			3,686,616			2,919,753			1,584,376			(5,094	)
Net change in unrealized appreciation (depreciation) on:
Allocation from the applicable Underlying Master Portfolios from investments, futures contracts, forward foreign currency exchange contracts and foreign currency transactions		4,232,091			5,104,602			4,294,590			2,424,507			158,285
Futures contracts		337,127			307,435			199,908			70,085			5,423
Forward foreign currency exchange contracts		102,158			119,883			93,589			50,008			2,406
Foreign currency translations		2,598			1,336			1,225			538			—
Investments — affiliated		739,226			913,992			681,586			405,690			25,841
Investments — unaffiliated		21,348			74,196			68,832			45,725			—
		5,434,548			6,521,444			5,339,730			2,996,553			191,955
Net realized and unrealized gain		8,702,394			10,208,060			8,259,483			4,580,929			186,861
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	10,238,016		$	11,578,135		$	9,207,064		$	5,131,199		$	218,773

^(a)  Commenced operations on October 30, 2019.

See notes to financial statements.

FINANCIAL STATEMENTS 77

Statements of Changes in Net Assets

	LifePath Dynamic 2025 Master Portfolio						LifePath Dynamic 2035 Master Portfolio
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	1,535,622		$	1,564,885		$	1,370,075		$	1,282,040
Net realized gain		3,267,846			1,649,650			3,686,616			2,056,317
Net change in unrealized appreciation (depreciation)		5,434,548			(5,137,828	)		6,521,444			(6,160,981	)
Net increase (decrease) in net assets resulting from operations		10,238,016			(1,923,293	)		11,578,135			(2,822,624	)
CAPITAL TRANSACTIONS
Proceeds from contributions		40,654,801			18,530,872			35,063,826			12,543,337
Value of withdrawals		(25,832,884	)		(37,906,609	)		(20,140,599	)		(22,338,088	)
Net increase (decrease) in net assets derived from capital transactions		14,821,917			(19,375,737	)		14,923,227			(9,794,751	)
NET ASSETS
Total increase (decrease) in net assets		25,059,933			(21,299,030	)		26,501,362			(12,617,375	)
Beginning of year		44,363,236			65,662,266			42,880,995			55,498,370
End of year	$	69,423,169		$	44,363,236		$	69,382,357		$	42,880,995

See notes to financial statements.

78 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets  (continued)

	LifePath Dynamic 2045 Master Portfolio						LifePath Dynamic 2055 Master Portfolio
	Year Ended December 31,						Year Ended December 31,
	2019			2018			2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	947,581		$	797,042		$	550,270		$	435,004
Net realized gain		2,919,753			1,229,751			1,584,376			562,245
Net change in unrealized appreciation (depreciation)		5,339,730			(4,588,826	)		2,996,553			(2,530,570	)
Net increase (decrease) in net assets resulting from operations		9,207,064			(2,562,033	)		5,131,199			(1,533,321	)
CAPITAL TRANSACTIONS
Proceeds from contributions		24,344,103			10,676,533			14,024,845			8,591,118
Value of withdrawals		(13,233,618	)		(14,448,452	)		(8,767,876	)		(9,301,137	)
Net increase (decrease) in net assets derived from capital transactions		11,110,485			(3,771,919	)		5,256,969			(710,019	)
NET ASSETS
Total increase (decrease) in net assets		20,317,549			(6,333,952	)		10,388,168			(2,243,340	)
Beginning of year		30,184,684			36,518,636			17,103,884			19,347,224
End of year	$	50,502,233		$	30,184,684		$	27,492,052		$	17,103,884

See notes to financial statements.

FINANCIAL STATEMENTS 79

Statements of Changes in Net Assets  (continued)

	LifePath Dynamic 2065 Master Portfolio
	Period from 10/30/19 (a) to 12/31/19
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	31,912
Net realized loss		(5,094	)
Net change in unrealized appreciation (depreciation)		191,955
Net increase in net assets resulting from operations		218,773
CAPITAL SHARE TRANSACTIONS
Proceeds from contributions		4,000,000
Value of withdrawals		(470	)
Net increase in net assets derived from capital transactions		3,999,530
NET ASSETS
Total increase in net assets		4,218,303
Beginning of period		—
End of period	$	4,218,303

^(a)  Commencement of operations.

See notes to financial statements.

80 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights

	LifePath Dynamic 2025 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		19.88	%		(4.33	)%		15.85	%		7.25	%		(1.50	)%
Ratios to Average Net Assets(a)
Total expenses		0.55	%		0.55	%		0.53	%		0.56	%		0.57	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.21	%		0.19	%		0.22	%		0.23	%
Net investment income		2.65	%		2.46	%		2.05	%		2.10	%		1.98	%
Supplemental Data
Net assets, end of year (000)	$	69,423		$	44,363		$	65,662		$	62,551		$	65,105
Portfolio turnover rate(b)		35	%		38	%		32	%		54	%		51	%

^(a) Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019
Large Cap Index Master Portfolio		2015 — 2017

	Range of Periods
Master Small Cap Index Series		2015 — 2017
Master Total Return Portfolio		2016 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.08	%		0.07	%		0.07	%		0.06	%		0.05	%
Investments in underlying funds		0.10	%		0.10	%		0.14	%		0.11	%		0.13	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015 — 2017
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2017

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares Exchange-Traded Funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 81

Financial Highlights  (continued)

	LifePath Dynamic 2035 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		24.09	%		(6.09	)%		19.93	%		7.99	%		(1.65	)%
Ratios to Average Net Assets(a)
Total expenses		0.55	%		0.55	%		0.53	%		0.55	%		0.57	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.20	%		0.18	%		0.20	%		0.20	%
Net investment income		2.54	%		2.30	%		1.97	%		2.13	%		2.02	%
Supplemental Data
Net assets, end of year (000)	$	69,382		$	42,881		$	55,498		$	57,377		$	56,100
Portfolio turnover rate(b)		42	%		40	%		35	%		76	%		44	%

^(a) Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019
Large Cap Index Master Portfolio		2015 — 2017

	Range of Periods
Master Small Cap Index Series		2015 — 2017
Master Total Return Portfolio		2016 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.10	%		0.08	%		0.09	%		0.07	%		0.06	%
Investments in underlying funds		0.12	%		0.12	%		0.16	%		0.13	%		0.16	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015 — 2017
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2019

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares Exchange-Traded Funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b) Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

82 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

	LifePath Dynamic 2045 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		26.82	%		(7.86	)%		22.72	%		8.52	%		(1.87	)%
Ratios to Average Net Assets(a)
Total expenses		0.58	%		0.57	%		0.56	%		0.56	%		0.59	%
Total expenses after fees waived and/or reimbursed		0.20	%		0.20	%		0.18	%		0.18	%		0.17	%
Net investment income		2.50	%		2.14	%		1.97	%		2.12	%		2.02	%
Supplemental Data
Net assets, end of year (000)	$	50,502		$	30,185		$	36,519		$	36,423		$	34,517
Portfolio turnover rate(b)		49	%		47	%		46	%		75	%		50	%

^(a) Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019
Large Cap Index Master Portfolio		2015 — 2017

	Range of Periods
Master Small Cap Index Series		2015 — 2017
Master Total Return Portfolio		2016 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.11	%		0.09	%		0.09	%		0.07	%		0.06	%
Investments in underlying funds		0.12	%		0.12	%		0.17	%		0.15	%		0.18	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015 — 2017
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2017

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares Exchange-Traded Funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 83

Financial Highlights  (continued)

	LifePath Dynamic 2055 Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		26.92	%		(8.10	)%		23.00	%		8.58	%		(2.02	)%
Ratios to Average Net Assets(a)
Total expenses		0.62	%		0.62	%		0.62	%		0.63	%		0.72	%
Total expenses after fees waived and/or reimbursed		0.19	%		0.19	%		0.17	%		0.19	%		0.17	%
Net investment income		2.47	%		2.10	%		1.98	%		2.09	%		2.03	%
Supplemental Data
Net assets, end of year (000)	$	27,492		$	17,104		$	19,347		$	19,386		$	15,850
Portfolio turnover rate(b)		54	%		57	%		59	%		80	%		49	%

^(a)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
Active Stock Master Portfolio		2015 — 2019
CoreAlpha Bond Master Portfolio		2015 — 2019
International Tilts Master Portfolio		2015 — 2019
Large Cap Index Master Portfolio		2015 — 2017

	Range of Periods
Master Small Cap Index Series		2015 — 2017
Master Total Return Portfolio		2016 — 2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived and excludes expenses incurred indirectly as a result of investments in underlying funds:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.11	%		0.09	%		0.08	%		0.07	%		0.07	%
Investments in underlying funds		0.13	%		0.12	%		0.15	%		0.18	%		0.18	%

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2015 — 2019
BlackRock Cash Funds: Prime		2015 — 2017
BlackRock Cash Funds: Treasury		2016 — 2019
BlackRock Commodity Strategies Fund		2015 — 2017

	Range of Periods
BlackRock Advantage Emerging Markets Fund		2015 — 2019
BlackRock Tactical Opportunities Fund		2016 — 2019
iShares Exchange-Traded Funds		2015 — 2019
iShares Developed Real Estate Index Fund		2019

^(b) Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

84 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

	LifePath Dynamic 2065 Master Portfolio
	Period from 10/30/19 (a) to 12/31/19
Total Return
Total return		5.42	%(b)
Ratios to Average Net Assets(c)(d)
Total expenses		1.16	%(e)
Total expenses after fees waived and/or reimbursed		0.21	%
Net investment income		4.56	%
Supplemental Data
Net assets end of period (000)	$	4,218
Portfolio turnover rate(f)		3	%

^(a) Commencement of operations.

^(b)  Aggregate total return.

^(c)  Annualized.

^(d)  Includes the LifePath Dynamic Master Portfolio’s pro rata portion of expenses and share of the allocated net investment income from the following master portfolios (collectively, the “Underlying Master Portfolios”):

	Range of Periods
CoreAlpha Bond Master Portfolio		2019
Active Stock Master Portfolio		2019
International Tilts Master Portfolio		2019

	Range of Periods
Master Total Return Portfolio		2019

Includes the LifePath Dynamic Master Portfolio’s share of the Underlying Master Portfolios’ allocated fees waived of 0.12%. Excludes expenses incurred indirectly as a result of investments in underlying funds of 0.13%.

The ratios do not reflect any expenses incurred indirectly as a result of investments in the following underlying funds:

	Range of Periods
BlackRock Cash Funds: Institutional		2019
BlackRock Cash Funds: Treasury		2019
BlackRock Advantage Emerging Markets Fund		2019

	Range of Periods
iShares Exchange-Traded Funds		2019
iShares Developed Real Estate Index Fund		2019

^(e)  Audit fees were not annualized in the calculation of expense ratios. If this expense was annualized, the total expenses would have been 3.02%.

^(f)  Includes the purchases and sales of the underlying funds and the Underlying Master Portfolios.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 85

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. The financial statements and these accompanying notes relate to five series of MIP: LifePath^® Dynamic 2025 Master Portfolio, LifePath^® Dynamic 2035 Master Portfolio, LifePath^® Dynamic 2045 Master Portfolio, LifePath^® Dynamic 2055 Master Portfolio and LifePath^® Dynamic 2065 Master Portfolio (each, a “LifePath Dynamic Master Portfolio” and together, the “LifePath Dynamic Master Portfolios”). Each of the LifePath Dynamic Master Portfolios is classified as diversified.

As of period end, the investment of LifePath Dynamic 2025 Master Portfolio, LifePath Dynamic 2035 Master Portfolio, LifePath Dynamic 2045 Master Portfolio, LifePath Dynamic 2055 Master Portfolio and LifePath Dynamic 2065 Master Portfolio in the Active Stock Master Portfolio represented 30.7%, 42.2%, 50.6%, 52.4% and 52.1%, respectively, of net assets. The investment of LifePath Dynamic 2025 Master Portfolio, LifePath Dynamic 2035 Master Portfolio, LifePath Dynamic 2045 Master Portfolio, LifePath Dynamic 2055 Master Portfolio and LifePath Dynamic 2065 Master Portfolio in the CoreAlpha Bond Master Portfolio represented 30.2%, 13.3%, 2.4%, 0.9% and 0.8%, respectively, of net assets. As such, financial statements of the Active Stock Master Portfolio and CoreAlpha Bond Master Portfolio, including the Schedules of Investments, should be read in conjunction with each respective LifePath Dynamic Master Portfolio’s financial statements. Active Stock Master Portfolio’s and CoreAlpha Bond Master Portfolio’s financial statements are available, without charge, on the U.S. Securities and Exchange Commission’s (“SEC’s”) website at sec.gov.

The LifePath Dynamic Master Portfolios will generally invest in other registered investment companies (each, an “Underlying Fund” and collectively, the “Underlying Funds”) that are managed by subsidiaries of BlackRock, Inc. (“BlackRock”) and its affiliates, which are affiliates of the LifePath Dynamic Master Portfolios. The LifePath Dynamic Master Portfolios may also invest in other master portfolios (“Underlying Master Portfolios”) that are managed by subsidiaries of BlackRock.

The value of a LifePath Dynamic Master Portfolio’s investment in each of Active Stock Master Portfolio, CoreAlpha Bond Master Portfolio, International Tilts Master Portfolio and Master Total Return Portfolio reflects that LifePath Dynamic Master Portfolio’s proportionate interest in the net assets of that master portfolio. As of period end, the LifePath Dynamic Master Portfolios held interests in Underlying Master Portfolios as follows:

	Active Stock Master Portfolio			CoreAlpha Bond Master Portfolio			International Tilts Master Portfolio		Master Total Return Portfolio
LifePath Dynamic 2025 Master Portfolio		4.2	%		1.1	%		3.3		0.02	%
LifePath Dynamic 2035 Master Portfolio		5.8			0.5			5.2		0.01
LifePath Dynamic 2045 Master Portfolio		5.0			0.1			4.8		0.00
LifePath Dynamic 2055 Master Portfolio		2.8			0.0			2.8		0.00
LifePath Dynamic 2065 Master Portfolio		0.4			0.0			0.4		0.00

The LifePath Dynamic Master Portfolios, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, are included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

On November 12-13, 2019, the Board of Trustees of MIP (the “Board”) approved a proposal pursuant to which each “feeder” fund will cease to invest in its corresponding LifePath Dynamic Master Portfolio as part of a “master-feeder” structure and instead each “feeder” fund will operate as a stand-alone fund. These changes are expected to be effective on or about March 9, 2020.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. Each LifePath Dynamic Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the LifePath Dynamic Master Portfolios are informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain. Interest income, including amortization and accretion of premiums and discounts on debt securities, is recognized on an accrual basis.

Each LifePath Dynamic Master Portfolio records daily its proportionate share of the Underlying Master Portfolios’ income, expenses and realized and unrealized gains and losses.

Foreign Currency Translation:Each LifePath Dynamic Master Portfolio’s books and records are maintained in U.S. dollars. Securities and other assets and liabilities denominated in foreign currencies are translated into U.S. dollars using exchange rates determined as of the close of trading on the New York Stock Exchange (“NYSE”). Purchases and sales of investments are recorded at the rates of exchange prevailing on the respective dates of such transactions. Generally, when the U.S. dollar rises in value against a foreign currency, the investments denominated in that currency will lose value; the opposite effect occurs if the U.S. dollar falls in relative value.

Each LifePath Dynamic Master Portfolio does not isolate the portion of the results of operations arising as a result of changes in the exchange rates from the changes in the market prices of investments held or sold for financial reporting purposes. Accordingly, the effects of changes in exchange rates on investments are not segregated in

86 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

the Statements of Operations from the effects of changes in market prices of those investments, but are included as a component of net realized and unrealized gain (loss) from investments. Each LifePath Dynamic Master Portfolio reports realized currency gains (losses) on foreign currency related transactions as components of net realized gain (loss) for financial reporting purposes, whereas such components are generally treated as ordinary income for U.S. federal income tax purposes.

Segregation and Collateralization:In cases where a LifePath Dynamic Master Portfolio enters into certain investments (e.g., futures contracts and forward foreign currency exchange contracts) that would be treated as “senior securities” for 1940 Act purposes, a LifePath Dynamic Master Portfolio may segregate or designate on its books and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment or borrowings to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the LifePath Dynamic Master Portfolios may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, a LifePath Dynamic Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. A LifePath Dynamic Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against a LifePath Dynamic Master Portfolio, which cannot be predicted with any certainty.

Other: Expenses directly related to a LifePath Dynamic Master Portfolio are charged to that LifePath Dynamic Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The LifePath Dynamic Master Portfolios’ investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the NYSE (generally 4:00 p.m., Eastern time) (or if the reporting date falls on a day the NYSE is closed, investments are valued at fair value as of the period end). U.S. GAAP defines fair value as the price the LifePath Dynamic Master Portfolios would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The LifePath Dynamic Master Portfolios determine the fair values of their financial instruments using various independent dealers or pricing services under policies approved by the Board. The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of each LifePath Dynamic Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

Generally, trading in foreign instruments is substantially completed each day at various times prior to the close of trading on the NYSE. Occasionally, events affecting the values of such instruments may occur between the foreign market close and the close of trading on the NYSE that may not be reflected in the computation of the LifePath Dynamic Master Portfolios’ net assets. Each business day, the LifePath Dynamic Master Portfolios use a pricing service to assist with the valuation of certain foreign exchange-traded equity securities and foreign exchange-traded andover-the-counter (“OTC”) options (the “Systematic Fair Value Price”). Using current market factors, the Systematic Fair Value Price is designed to value such foreign securities and foreign options at fair value as of the close of trading on the NYSE, which follows the close of the local markets.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

• Forward foreign currency exchange contracts are valued at the mean between the bid and ask prices and are determined as of the close of trading on the NYSE based on that day’s prevailing forward exchange rate for the underlying currencies. Interpolated values are derived when the settlement date of the contract is an interim date for which quotations are not available.

• Swap agreements are valued utilizing quotes received daily by the LifePath Dynamic Master Portfolios’ pricing service or through brokers, which are derived using daily swap curves and models that incorporate a number of market data factors, such as discounted cash flows, trades and values of the underlying reference instruments.

• The LifePath Dynamic Master Portfolios record their proportionate investment in the Underlying Master Portfolios at fair value, which is based upon their pro rata ownership in the net assets of the Underlying Master Portfolios.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that each LifePath Dynamic Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

NOTESTO FINANCIAL STATEMENTS 87

Notes to Financial Statements  (continued)

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that each LifePath Dynamic Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

As of December 31, 2019, certain investments of the LifePath Dynamic Master Portfolios were valued using NAV as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

4. SECURITIES AND OTHER INVESTMENTS

Securities Lending:Certain LifePath Dynamic Master Portfolios may lend their securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the LifePath Dynamic Master Portfolios collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by each LifePath Dynamic Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the LifePath Dynamic Master Portfolio and any additional required collateral is delivered to the LifePath Dynamic Master Portfolio, or excess collateral returned by the LifePath Dynamic Master Portfolio, on the next business day. During the term of the loan, the LifePath Dynamic Master Portfolios are entitled to all distributions made on or in respect of the loaned securities, but do not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as investment companies and common stocks in the LifePath Dynamic Master Portfolios’ Schedules of Investments, and the value of any related collateral are shown separately in the Statements of Assets and Liabilities as a component of investments at value-unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedules of Investments.

Securities lending transactions are entered into by the LifePath Dynamic Master Portfolios under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the LifePath Dynamic Master Portfolios, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and a LifePath Dynamic Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the LifePath Dynamic Master Portfolios’ securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
LifePath Dynamic 2025 Master Portfolio
Goldman Sachs & Co.	$	940,428	$	(940,428	)	$	—
Wells Fargo Bank, National Association		18,684		(18,684	)		—
	$	959,112	$	(959,112	)	$	—

88 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
LifePath Dynamic 2035 Master Portfolio
Bank of America N.A.	$	1,989,908	$	(1,989,908	)	$	—
Wells Fargo Bank, National Association		84,795		(84,795	)		—
Wells Fargo Securities LLC		43,596		(43,596	)		—
	$	2,118,299	$	(2,118,299	)	$	—
LifePath Dynamic 2045 Master Portfolio
Wells Fargo Bank, National Association	$	136,217	$	(136,217	)	$	—
	$	136,217	$	(136,217	)	$	—
LifePath Dynamic 2055 Master Portfolio
The Bank of Nova Scotia	$	6,228	$	(6,228	)	$	—
	$	6,228	$	(6,228	)	$	—
LifePath Dynamic 2065 Master Portfolio
Citigroup Global Markets Inc.	$	6,228	$	(6,228	)	$	—
JP Morgan Securities llc		84,823		(84,823	)		—
Scotia Capital (USA) Inc.		136,483		(136,483	)		—
	$	227,534	$	(227,534	)	$	—

^(a)  Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by each LifePath Dynamic Master Portfolio is disclosed in the LifePath Dynamic Master Portfolio’s Statements of Assets and Liabilities.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the LifePath Dynamic Master Portfolios benefit from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”). BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. Each LifePath Dynamic Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the LifePath Dynamic Master Portfolios.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The LifePath Dynamic Master Portfolios engage in various portfolio investment strategies using derivative contracts both to increase the returns of the LifePath Dynamic Master Portfolios and/or to manage their exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedules of Investments. These contracts may be transacted on an exchange orover-the-counter (“OTC.”).

Futures Contracts: Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

Futures contracts are agreements between the LifePath Dynamic Master Portfolios and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the LifePath Dynamic Master Portfolios are required to deposit initial margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statements of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedules of Investments and cash deposited, if any, is shown as cash pledged for futures contracts in the Statements of Assets and Liabilities. Pursuant to the contract, the LifePath Dynamic Master Portfolios agree to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statements of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statements of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

Forward Foreign Currency Exchange Contracts: Forward foreign currency exchange contracts are entered into to gain or reduce exposure to foreign currencies (foreign currency exchange rate risk).

A forward foreign currency exchange contract is an agreement between two parties to buy and sell a currency at a set exchange rate on a specified date. These contracts help to manage the overall exposure to the currencies in which some of the investments held by the LifePath Dynamic Master Portfolios are denominated and in some cases, may be used to obtain exposure to a particular market.

The contract ismarked-to-market daily and the change in market value is recorded as unrealized appreciation (depreciation) in the Statements of Assets and Liabilities. When a contract is closed, a realized gain or loss is recorded in the Statements of Operations equal to the difference between the value at the time it was opened and the value at the time it was closed.Non-deliverable forward foreign currency exchange contracts are settled with the counterparty in cash without the delivery of foreign currency. The use of forward foreign currency exchange contracts involves the risk that the value of a forward foreign currency exchange contract changes unfavorably due to movements in the value of the referenced foreign currencies, and such value may exceed the amounts reflected in the Statements of Assets and Liabilities. Cash

NOTESTO FINANCIAL STATEMENTS 89

Notes to Financial Statements  (continued)

amounts pledged for forward foreign currency exchange contracts are considered restricted and are included in cash pledged as collateral for OTC derivatives in the Statements of Assets and Liabilities.

Master Netting Arrangements: In order to define their contractual rights and to secure rights that will help mitigate their counterparty risk, the LifePath Dynamic Master Portfolios may enter into an International Swaps and Derivatives Association, Inc. Master Agreement (“ISDA Master Agreement”) or similar agreement with their counterparties. An ISDA Master Agreement is a bilateral agreement between each LifePath Dynamic Master Portfolio and a counterparty that governs certain OTC derivatives and typically contains, among other things, collateral posting terms and netting provisions in the event of a default and/or termination event. Under an ISDA Master Agreement, each LifePath Dynamic Master Portfolio may, under certain circumstances, offset with the counterparty certain derivative financial instruments’ payables and/or receivables with collateral held and/or posted and create one single net payment. The provisions of the ISDA Master Agreement typically permit a single net payment in the event of default including the bankruptcy or insolvency of the counterparty. Bankruptcy or insolvency laws of a particular jurisdiction may restrict or prohibit the right of offset in bankruptcy, insolvency or other events.

Collateral Requirements: For derivatives traded under an ISDA Master Agreement, the collateral requirements are typically calculated by netting themark-to-market amount for each transaction under such agreement and comparing that amount to the value of any collateral currently pledged by the LifePath Dynamic Master Portfolio and the counterparty.

Cash collateral that has been pledged to cover obligations of the LifePath Dynamic Master Portfolios and cash collateral received from the counterparty, if any, is reported separately in the Statements of Assets and Liabilities as cash pledged as collateral and cash received as collateral, respectively.Non-cash collateral pledged by the LifePath Dynamic Master Portfolios, if any, is noted in the Schedules of Investments. Generally, the amount of collateral due from or to a counterparty is subject to a certain minimum transfer amount threshold before a transfer is required, which is determined at the close of business of the LifePath Dynamic Master Portfolios. Any additional required collateral is delivered to/pledged by the LifePath Dynamic Master Portfolios on the next business day. Typically, the counterparty is not permitted to sell,re-pledge or use cash andnon-cash collateral it receives. A LifePath Dynamic Master Portfolio generally agrees not to usenon-cash collateral that it receives but may, absent default or certain other circumstances defined in the underlying ISDA Master Agreement, be permitted to use cash collateral received. In such cases, interest may be paid pursuant to the collateral arrangement with the counterparty. To the extent amounts due to the LifePath Dynamic Master Portfolios from their counterparties are not fully collateralized, they bear the risk of loss from counterpartynon-performance. Likewise, to the extent the LifePath Dynamic Master Portfolios have delivered collateral to a counterparty and stand ready to perform under the terms of their agreement with such counterparty, they bear the risk of loss from a counterparty in the amount of the value of the collateral in the event the counterparty fails to return such collateral. Based on the terms of agreements, collateral may not be required for all derivative contracts.

For financial reporting purposes, the LifePath Dynamic Master Portfolios do not offset derivative assets and derivative liabilities that are subject to netting arrangements, if any, in the Statements of Assets and Liabilities.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the LifePath Dynamic Master Portfolios, entered into an Investment Advisory Agreement with the Manager, the LifePath Dynamic Master Portfolios’ investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of each LifePath Dynamic Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of each LifePath Dynamic Master Portfolio.

For such services, each LifePath Dynamic Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.35% of the average daily value of each LifePath Dynamic Master Portfolio’s net assets.

With respect to each LifePath Dynamic Master Portfolio, the Manager entered into separatesub-advisory agreements with BlackRock International Limited (“BIL”), and BlackRock (Singapore) Limited (“BRS”) (collectively, the“Sub-Advisers”), each an affiliate of the Manager. The Manager pays each Sub-Advisor for services it provides for that portion of each LifePath Dynamic Master Portfolio for which it acts assub-adviser, a monthly fee that is equal to a percentage of the investment advisory fees paid by each LifePath Dynamic Master Portfolio to the Manager.

Administration: MIP, on behalf of the LifePath Dynamic Master Portfolios, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the LifePath Dynamic Master Portfolios’ ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the LifePath Dynamic Master Portfolios. BAL may delegate certain of its administration duties tosub-administrators.

BAL is not entitled to compensation for providing administrative services to the LifePath Dynamic Master Portfolios, for so long as BAL (or an affiliate) is entitled to compensation for providing administrative services to corresponding feeder funds that invest substantially all of their assets in the LifePath Dynamic Master Portfolios, or BAL (or an affiliate) receives investment advisory fees from the LifePath Dynamic Master Portfolios.

Expense Limitations and Waivers:BFA, with respect to each LifePath Dynamic Master Portfolio, has contractually agreed to waive and/or reimburse 0.30% of its investment advisory fees through April 30, 2020. These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. For the year ended December 31, 2019, the amounts waived and/or reimbursed were as follows:

	Amounts Waived
LifePath Dynamic 2025 Master Portfolio	$	173,221
LifePath Dynamic 2035 Master Portfolio		161,666
LifePath Dynamic 2045 Master Portfolio		113,321
LifePath Dynamic 2055 Master Portfolio		66,730
LifePath Dynamic 2065 Master Portfolio		2,090

90 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

With respect to each LifePath Dynamic Master Portfolio, the Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees each LifePath Dynamic Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. However, the Manager does not waive its investment advisory fees by the amount of investment advisory fees paid in connection with each LifePath Dynamic Master Portfolio’s investments in other affiliated investment companies, if any. For the year ended December 31, 2019, the amounts waived were as follows:

	Amounts Waived
LifePath Dynamic 2025 Master Portfolio	$	1,999
LifePath Dynamic 2035 Master Portfolio		1,920
LifePath Dynamic 2045 Master Portfolio		1,458
LifePath Dynamic 2055 Master Portfolio		1,411
LifePath Dynamic 2065 Master Portfolio		24

The fees and expenses of MIP’s trustees who are not “interested persons” of MIP, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the LifePath Dynamic Master Portfolios’ independent registered public accounting firm (together, the “independent expenses”) are paid directly by the LifePath Dynamic Master Portfolios. BAL and BFA have contractually agreed to reimburse these LifePath Dynamic Master Portfolios or provide an offsetting credit against the investment advisory fees paid by the LifePath Dynamic Master Portfolios in an amount equal to the independent expenses through April 30, 2029. These amounts are included in fees waived and/or reimbursed by the Manager in the Statements of Operations. If the LifePath Dynamic Master Portfolios do not pay administration fees, BFA agrees to cap the expenses of the LifePath Dynamic Master Portfolios at the rate at which it pays an investment advisory fee to BFA. For the year ended December 31, 2019, the amounts waived were as follows:

	Amounts Waived
LifePath Dynamic 2025 Master Portfolio	$	27,022
LifePath Dynamic 2035 Master Portfolio		26,927
LifePath Dynamic 2045 Master Portfolio		26,600
LifePath Dynamic 2055 Master Portfolio		26,354
LifePath Dynamic 2065 Master Portfolio		17,495

From time to time, BAL and BFA may waive such fees in whole or in part. Any such waiver will reduce the expenses of the LifePath Dynamic Master Portfolios and, accordingly, have a favorable impact on their performance. BAL may delegate certain of its administration duties tosub-administrators.

Securities Lending:The SEC has issued an exemptive order which permits BlackRock Institutional Trust Company, N.A. (“BTC”), an affiliate of the Manager, to serve as securities lending agent for the LifePath Dynamic Master Portfolios, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The LifePath Dynamic Master Portfolios are responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the LifePath Dynamic Master Portfolios bear to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a90-day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. Each LifePath Dynamic Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, each LifePath Dynamic Master Portfolio retains 82% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, each LifePath Dynamic Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 85% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by each LifePath Dynamic Master Portfolio is shown as securities lending income — affiliated – net in the Statements of Operations. For the year ended December 31, 2019, each LifePath Dynamic Master Portfolio paid BTC the following amounts securities lending agent services:

	LifePath Dynamic 2025 Master Portfolio		LifePath Dynamic 2035 Master Portfolio		LifePath Dynamic 2045 Master Portfolio		LifePath Dynamic 2055 Master Portfolio		LifePath Dynamic 2065 Master Portfolio
Amount	$	669	$	870	$	605	$	393	$	6

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, each LifePath Dynamic Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by each LifePath Dynamic Master Portfolio’s investment policies and restrictions. Each LifePath Dynamic Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

NOTESTO FINANCIAL STATEMENTS 91

Notes to Financial Statements  (continued)

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the LifePath Dynamic Master Portfolios did not participate in the Interfund Lending Program.

Trustees and Officers: Certain trustees and/or officers of MIP are directors and/or officers of BlackRock or its affiliates.

Other Transactions: Each LifePath Dynamic Master Portfolio may invest its positive cash balances in certain money market funds managed by the Manager or an affiliate. The income earned on these temporary cash investments is shown as income-affiliated in the Statements of Operations.

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments in the Underlying Funds and Underlying Master Portfolios, and excluding short-term securities, were as follows:

	LifePath Dynamic 2025 Master Portfolio		LifePath Dynamic 2035 Master Portfolio		LifePath Dynamic 2045 Master Portfolio		LifePath Dynamic 2055 Master Portfolio		LifePath Dynamic 2065 Master Portfolio
Purchases	$	32,809,486	$	34,606,835	$	25,508,888	$	14,709,809	$	3,945,139
Sales		19,020,147		21,523,010		17,398,504		11,024,035		119,833

8. INCOME TAX INFORMATION

Each LifePath Dynamic Master Portfolio, except for LifePath Dynamic 2065 Master Portfolio, is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the LifePath Dynamic Master Portfolios is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the LifePath Dynamic Master Portfolios. Therefore, no U.S. federal income tax provision is required. It is intended that the LifePath Dynamic Master Portfolios’ assets will be managed so an investor in the LifePath Dynamic Master Portfolios can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The LifePath Dynamic 2065 Master Portfolio is disregarded as an entity separate from its owner for tax purposes. As such, the owner of the LifePath Dynamic 2065 Master Portfolio is treated as the owner of the net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required.

Each LifePath Dynamic Master Portfolio, except for LifePath Dynamic 2065 Master Portfolio, files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on each LifePath Dynamic Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on each LifePath Dynamic Master Portfolio’s, except for LifePath Dynamic 2065 Master Portfolio state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the LifePath Dynamic Master Portfolios as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the LifePath Dynamic Master Portfolios’ financial statements.

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

	LifePath Dynamic 2025 Master Portfolio			LifePath Dynamic 2035 Master Portfolio			LifePath Dynamic 2045 Master Portfolio			LifePath Dynamic 2055 Master Portfolio			LifePath Dynamic 2065 Master Portfolio
Tax cost	$	68,842,931		$	67,241,131		$	46,308,459		$	24,840,061		$	4,204,935
Gross unrealized appreciation	$	7,344,131		$	7,479,465		$	5,055,794		$	2,715,236		$	211,590
Gross unrealized depreciation		(1,825,937	)		(1,440,280	)		(235,121	)		(44,698	)		(8,977	)
Net unrealized appreciation	$	5,518,194		$	6,039,185		$	4,820,673		$	2,670,538		$	202,613

9. BANK BORROWINGS

MIP, on behalf of the LifePath Dynamic Master Portfolios, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the LifePath Dynamic Master Portfolios may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the LifePath Dynamic Master Portfolios, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an

92 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statements of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the LifePath Dynamic Master Portfolios did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, certain LifePath Dynamic Master Portfolios invest in securities or other instruments and may enter into certain transactions, and such activities subject each LifePath Dynamic Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. Each LifePath Dynamic Master Portfolio’s prospectus provides details of the risks to which each LifePath Dynamic Master Portfolio is subject.

The LifePath Dynamic Master Portfolios may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk:The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. A LifePath Dynamic Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that a LifePath Dynamic Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. A LifePath Dynamic Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause each LifePath Dynamic Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of a LifePath Dynamic Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which a LifePath Dynamic Master Portfolio invests.

Counterparty Credit Risk: The LifePath Dynamic Master Portfolios may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The LifePath Dynamic Master Portfolios manage counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the LifePath Dynamic Master Portfolios to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the LifePath Dynamic Master Portfolios’ exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statements of Assets and Liabilities, less any collateral held by the LifePath Dynamic Master Portfolios.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

A LifePath Dynamic Master Portfolio’s risk of loss from counterparty credit risk on OTC derivatives is generally limited to the aggregate unrealized gain less the value of any collateral held by such LifePath Dynamic Master Portfolio.

With exchange-traded futures, there is less counterparty credit risk to the LifePath Dynamic Master Portfolios since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, a LifePath Dynamic Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the LifePath Dynamic Master Portfolios.

Concentration Risk:Certain Funds invest a significant portion of their assets in fixed-income securities and/or use derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and otherfixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Funds may be subject to a greater risk of rising interest rates due to the current period of historically low rates.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the LifePath Dynamic Master Portfolios through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 93

Report of Independent Registered Public Accounting Firm Master Investment Portfolio

To the Board of Trustees of

Master Investment Portfolio and Investors of each of the five series listed in the table below

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities, including the schedules of investments, of each of the series listed in the table below (five of the series constituting Master Investment Portfolio, hereafter collectively referred to as the “Master Portfolios”) as of December 31, 2019, the related statements of operations and of changes in net assets for each of the periods indicated in the table below, including the related notes, and the financial highlights for each of the periods indicated in the table below (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Master Portfolios as of December 31, 2019, the results of each of their operations, the changes in each of their net assets, and each of the financial highlights for each of the periods indicated in the table below, in conformity with accounting principles generally accepted in the United States of America.

Master Portfolio	Statement of operations	Statement of changes in net assets	Financial highlights
LifePath® Dynamic 2025 Master Portfolio LifePath® Dynamic 2035 Master Portfolio LifePath® Dynamic 2045 Master Portfolio LifePath® Dynamic 2055 Master Portfolio	For the year ended December 31, 2019	For the years ended December 31, 2019 and 2018	For the years ended December 31, 2019, 2018, 2017, 2016 and 2015
LifePath® Dynamic 2065 Master Portfolio	For the period October 30, 2019 (commencement of operations) through December 31, 2019

Basis for Opinions

These financial statements are the responsibility of the Master Portfolios’ management. Our responsibility is to express an opinion on the Master Portfolios’ financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolios in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, administrator of the Master Portfolios, transfer agents and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinions.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

94 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Disclosure of Investment Advisory Agreement

The Board of Trustees of Master Investment Portfolio (the “Master Fund”) met in person on May14-15, 2019 (the “Organizational Meeting) to consider the approval of the proposed investment advisory agreement (the “Agreement”) between the Master Fund, on behalf LifePath Dynamic 2065 Master Portfolio (the “Master Portfolio”), a series of the Master Fund, and BlackRock Fund Advisors (the “Manager” or “BlackRock”), the Master Fund’s investment advisor. BlackRock LifePath Dynamic 2065 Fund (the “Portfolio”), a series of BlackRock Funds III (the “Fund”), is a “feeder” fund that invests all of its investable assets in the Master Portfolio. Accordingly, the Board of Trustees of the Fund also considered the approval of the proposed Agreement with respect to the Master Portfolio. The Agreement was the same agreement that had been previously approved by the Board of the Master Fund with respect to certain other master portfolios of the Master Fund. For simplicity: (a) the Board of Trustees of the Master Fund and the Board of Trustees of the Fund are referred to herein collectively as the “Board,” and the members are referred to as “Board Members;” and (b) the shareholders of the Portfolio and the interest holders of the Master Portfolio are referred to as “shareholders.” The Master Portfolio and the Portfolio each commenced operations in October, 2019.

Activities and Composition of the Board

On the date of the Organizational Meeting, the Board consisted of fifteen individuals, thirteen of whom were not “interested persons” of the Master Fund or the Fund as defined in the Investment Company Act of 1940, as amended (the “1940 Act”) (the “Independent Board Members”). The Board Members are responsible for the oversight of the operations of the Master Fund or Fund, as pertinent, and perform the various duties imposed on the directors of investment companies by the 1940 Act. The Independent Board Members have retained independent legal counsel to assist them in connection with their duties. The Chair of the Board is an Independent Board Member. The Board has established five standing committees: an Audit Committee, a Governance and Nominating Committee, a Compliance Committee, a Performance Oversight Committee and an Ad Hoc Topics Committee, each of which is chaired by an Independent Board Member and composed of Independent Board Members (except for the Ad Hoc Topics Committee, which also has one interested Board Member).

The Agreement

Consistent with the requirements of the 1940 Act, the Board of the Master Fund is required to consider the initial approval of the Agreement. In connection with this deliberative process, the Board assessed, among other things, the nature, extent and quality of the services to be provided to the Master Portfolio and the Portfolio by BlackRock, BlackRock’s personnel and affiliates, including (as applicable): investment management; accounting, administrative and shareholder services; oversight of the Master Portfolio and Portfolio service providers; risk management and oversight; legal and compliance services; and ability to meet applicable legal and regulatory requirements.

Board Considerations in Approving the Agreement

The Approval Process: At the Organizational Meeting, the Board reviewed materials relating to its consideration of the proposed Agreement. The Board considered all factors it believed relevant with respect to the Master Portfolio and the Portfolio, including, among other things: (a) the nature, extent and quality of the services to be provided by BlackRock; (b) the investment performance of BlackRock portfolio management; (c) the advisory fee and the estimated cost of the services and estimated profits to be realized by BlackRock and its affiliates from their relationship with the Master Portfolio and the Portfolio; (d) the sharing of potential economies of scale;(e) fall-out benefits to BlackRock and its affiliates as a result of BlackRock’s relationship with the Master Portfolio and the Portfolio; (f) possible alternatives to the proposed Agreement; (g) the policies and practices of BlackRock with respect to portfolio transactions for the Portfolio; (h) BlackRock’s portfolio compliance systems and capabilities; and (i) other factors deemed relevant by the Board Members.

In considering approval of the Agreement, the Board met with the relevant investment advisory personnel from BlackRock and considered all information it deemed reasonably necessary to evaluate the terms of the Agreement. The Board received materials in advance of the Organizational Meeting relating to its consideration of the Agreement, including (a) information independently compiled and prepared by Broadridge Financial Solutions, Inc. (“Broadridge”) regarding the Portfolio’s fees and estimated expense ratio as compared with a peer group of funds as determined by Broadridge (“Expense Peers”); (b) information regarding BlackRock’s economic outlook for the Master Portfolio and the Portfolio and its general investment outlook for the markets; (c) information regarding fees paid to service providers that are affiliates of BlackRock; and (d) information outlining the legal duties of the Board under the 1940 Act with respect to the consideration and approval of the Agreement. The Board also noted information received at prior Board meetings concerning compliance records and regulatory matters relating to BlackRock.

The Board also considered other matters it deemed important to the approval process, such as other payments made to BlackRock or its affiliates relating to securities lending and cash management and BlackRock’s services related to the valuation and pricing of the portfolio holdings of the Master Portfolio. The Board noted the willingness of BlackRock personnel to engage in open, candid discussions with the Board. The Board did not identify any particular information as determinative, and each Board Member may have attributed different weights to the various items considered.

A. Nature, Extent and Quality of the Services Provided by BlackRock: The Board, including the Independent Board Members, reviewed the nature, extent and quality of services to be provided by BlackRock, including the investment advisory services to be provided to the Master Portfolio. The Board received information concerning the investment philosophy and investment process to be used by BlackRock in managing the Master Portfolio, as well as a description of the capabilities, personnel and services of BlackRock. The Board considered the scope of the services provided by BlackRock to the Master Portfolio and the Portfolio under the Agreement relative to services typically provided by third parties to other funds. The Board noted that the standard of care applicable under the Agreement was comparable to that found generally in investment company advisory agreements. The Board concluded that the scope of BlackRock’s services to be provided to the Master Portfolio and the Portfolio was consistent with the Master Portfolio’s and the Portfolio’s operational requirements, including, in addition to seeking to meet the Master Portfolio’s investment objective(s), compliance with investment restrictions, tax and reporting requirements and related shareholder services.

The Board, including the Independent Board Members, also considered the quality of the administrative and othernon-investment advisory services to be provided by BlackRock and its affiliates to the Master Portfolio and the Portfolio. The Board evaluated the procedures of BlackRock designed to fulfill its fiduciary duty to the Master Portfolio and the Portfolio with respect to possible conflicts of interest, including BlackRock’s code of ethics (regulating the personal trading of BlackRock’s officers and

DISCLOSUREOF INVESTMENT ADVISORY AGREEMENT 95

Disclosure of Investment Advisory Agreement  (continued)

employees), the procedures by which BlackRock allocates trades among its various investment advisory clients, the integrity of the systems in place to ensure compliance with the foregoing and the record of BlackRock in these matters. The Board also noted information received at prior Board meetings concerning standards of BlackRock with respect to the execution of portfolio transactions.

The Board considered, among other factors, with respect to BlackRock: the number, education and experience of investment personnel generally and the Master Portfolio’s portfolio management team; BlackRock’s research capabilities; investments by portfolio managers in the funds they manage; portfolio trading capabilities; use of technology; commitment to compliance; credit analysis capabilities; risk analysis and oversight capabilities; and the approach to training and retaining portfolio managers and other research, advisory and management personnel. The Board also considered BlackRock’s overall risk management program, including the continued efforts of BlackRock and its affiliates to address cybersecurity risks and the role of BlackRock’s Risk & Quantitative Analysis Group. The Board engaged in a review of BlackRock’s compensation structure with respect to the Master Portfolio’s portfolio management team and BlackRock’s ability to attract and retain high-quality talent and create performance incentives. The Board also considered the business reputation of BlackRock and its financial resources and concluded that BlackRock would be able to meet any reasonably foreseeable obligation under the Agreement.

In addition to investment advisory services, the Board considered the nature and quality of the administrative and othernon-investment advisory services to be provided to the Master Portfolio and the Portfolio. The Board considered that BlackRock and its affiliates will provide the Master Portfolio and the Portfolio with certain administrative, shareholder and other services (in addition to any such services provided to the Master Portfolio and the Portfolio by third parties) and officers and other personnel as are necessary for the operations of the Master Portfolio and the Portfolio. In particular, BlackRock and its affiliates will provide Master Portfolio and the Portfolio with administrative services, including, among others: (i) responsibility for disclosure documents, such as the prospectus, the summary prospectus (as applicable), the statement of additional information and periodic shareholder reports; (ii) oversight of daily accounting and pricing; (iii) responsibility for periodic filings with regulators; (iv) overseeing and coordinating the activities of other service providers, including, among others, the custodian, fund accountant, transfer agent, and auditor for the Master Portfolio and Portfolio; as applicable; (v) organizing Board meetings and preparing the materials for such Board meetings; (vi) providing legal and compliance support; (vii) furnishing analytical and other support to assist the Board in its consideration of strategic issues such as the merger, consolidation or repurposing of certainopen-end funds; and (viii) performing other administrative functions necessary for the operation of the Master Portfolio and the Portfolio, such as tax reporting, expense management, fulfilling regulatory filing requirements, overseeing the Fund’s distribution partners, and shareholder call center and other services. The Board reviewed the structure and duties of BlackRock’s fund administration, shareholder services, and legal & compliance departments and considered BlackRock’s policies and procedures for assuring compliance with applicable laws and regulations.

B. The Investment Performance of the Master Portfolio, the Portfolio and BlackRock: The Board, including the Independent Board Members, previously received and considered information about BlackRock’s investment performance for other funds. The Board, however, did not consider the performance history of the Master Portfolio and the Portfolio because the Master Portfolio and the Portfolio were newly organized and had not yet commenced operations as of the date of the Organizational Meeting.

C. Consideration of the Advisory/Management Fees and the Estimated Cost of the Services to be Provided and Estimated Profits to be Realized by BlackRock and its Affiliates from their Relationship with the Master Portfolio and the Portfolio: In connection with the initial approval of the Agreement, the Board, including the Independent Board Members, reviewed the Master Portfolio’s/Portfolio’s contractual advisory fee rate compared with those of its Expense Peers. The contractual advisory fee rate represents a combination of the advisory and any administrative fees, before taking into account any reimbursements or fee waivers. The Board also compared the Portfolio’s estimated total expense ratio, as well as the Master Portfolio’s/Portfolio’s estimated actual advisory fee rate, to those of the Portfolio’s Expense Peers. The total expense ratio represents a fund’s total net operating expenses, including any12b-1 or non12b-1 service fees. The total expense ratio gives effect to any expense reimbursements or fee waivers that benefit a fund, and the actual advisory fee rate gives effect to any advisory fee reimbursements or waivers that benefit a fund. Additionally, the Board noted information received at prior Board meetings concerning the services provided and the fees charged by BlackRock and its affiliates to other types of clients with similar investment mandates, as applicable, including institutional accounts andsub-advised mutual funds (including mutual funds sponsored by third parties).

The Board noted that the varying fee structures for fund of funds can limit the value of advisory fee comparisons. The Board noted that the Master Portfolio’s/Portfolio’s contractual advisory fee rate and estimated actual advisory fee rate each ranked second out of three funds, and the estimated total expense ratio ranked in the third quartile, relative to the Master Portfolio’s/Portfolio’s Expense Peers. The Board also noted that BlackRock and the Board have contractually agreed to waive a portion of the advisory fee for the Master Portfolio. Additionally, the Board noted that BlackRock and its affiliates have contractually agreed to reimburse or otherwise compensate the Master Portfolio/Portfolio for certain other fees and expenses.

Following consideration of this information, the Board, including the independent Board Members, concluded that the fees to be paid pursuant to the Agreement were fair and reasonable in light of the services provided.

As the Master Portfolio and Portfolio had not commenced operations as of the date of the Organizational Meeting, BlackRock was not able to provide the Board with specific information concerning the expected profits to be realized by BlackRock and its affiliates from their relationships with the Master Portfolio and the Portfolio. BlackRock, however, will provide the Board with such information at future meetings.

D. Economies of Scale: The Board, including the Independent Board Members, considered the extent to which economies of scale might be realized as the assets of the Master Portfolio and Portfolio increase, including the existence of fee waivers and/or expense caps, as applicable, noting that any contractual fee waivers and expense caps had been approved by the Board.

E. Other Factors Deemed Relevant by the Board Members: The Board, including a majority of the Independent Board Members, also took into account other ancillary or“fall-out” benefits that BlackRock or its affiliates may derive from BlackRock’s respective relationships with the Master Portfolio and the Portfolio, both tangible and intangible, such as BlackRock’s ability to leverage its investment professionals who manage other portfolios and risk management personnel, an increase in BlackRock’s profile in the investment advisory community, and the engagement of BlackRock’s affiliates as service providers to the Master Portfolio and the Portfolio, including for

96 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Disclosure of Investment Advisory Agreement  (continued)

administrative, distribution, securities lending and cash management services. The Board also considered BlackRock’s overall operations and its efforts to expand the scale of, and improve the quality of, its operations. The Board also noted that, subject to applicable law, BlackRock may use and benefit from third party research obtained by soft dollars generated by certain registered fund transactions to assist in managing all or a number of its other client accounts.

In connection with its consideration of the Agreement, the Board also considered information regarding BlackRock’s brokerage and soft dollar practices and reports from BlackRock which included information on brokerage commissions and trade execution practices that it had received at prior Board meetings.

The Board noted the competitive nature of theopen-end fund marketplace, and that shareholders are able to redeem their Portfolio shares if they believe that the Portfolio Fees’s and/or the Master Portfolio’s fees and expenses are too high or if they are dissatisfied with the performance of the Portfolio.

Conclusion

All the Board Members of the Master Fund present at the Organizational Meeting, including all the Independent Board Members present, approved the Agreement between the Manager and the Master Fund, with respect to the Master Portfolio, for atwo-year term beginning on the effective date of the Agreement. Based upon its evaluation of all of the aforementioned factors in their totality, as well as other information, the Board of the Master Fund, including a majority of the Independent Board Members, was satisfied that the terms of the Agreement were fair and reasonable and in the best interest of the Master Portfolio and its interest holders. The Board of the Fund, including the Independent Board Members, also considered the approval of the Agreement with respect to the Master Portfolio and found the Agreement to be satisfactory. In arriving at its decision to approve the Agreement, the Board of the Master Fund did not identify any single factor or group of factors asall-important or controlling, but considered all factors together, and different Board Members may have attributed different weights to the various factors considered. The Independent Board Members were also assisted by the advice of independent legal counsel in making this determination.

DISCLOSUREOF INVESTMENT ADVISORY AGREEMENT 97

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of BlackRock Funds III, on behalf of BlackRock LifePath^® Dynamic 2025 Fund, BlackRock LifePath^® Dynamic 2035 Fund, BlackRock LifePath^® Dynamic 2045 Fund, BlackRock LifePath^® Dynamic 2055 Fund and BlackRock LifePath^® Dynamic 2065 Fund, and MIP on behalf of LifePath^® Dynamic 2025 Master Portfolio, LifePath^® Dynamic 2035 Master Portfolio, LifePath^® Dynamic 2045 Master Portfolio, LifePath^® Dynamic 2055 Master Portfolio and LifePath^® Dynamic 2065 Master Portfolio met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements: The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

98 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

TRUSTEEAND OFFICER INFORMATION 99

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

100 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015) President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate.
(c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015.
(d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex.
(e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

TRUSTEEAND OFFICER INFORMATION 101

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge bycalling (800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Sub-Advisers

BlackRock International Limited

Edinburgh EH3 8BL,

United Kingdom

BlackRock (Singapore) Limited

079912 Singapore

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Distributor

BlackRock Investments, LLC

New York, NY 10022

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

102 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information

General Information

Householding

The LifePath^® Dynamic Funds will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the LifePath^® Dynamic Funds at (800) 441-7762.

Availability of Quarterly Schedule of Investments

The LifePath^® Dynamic Funds/LifePath^® Dynamic Master Portfolios file their complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information on Form N-Q. The LifePath^® Dynamic Funds’/LifePath^® Dynamic Master Portfolios’Forms N-PORT and N-Q are available on the SEC’s website at sec.gov. The LifePath^® Dynamic Funds’/LifePath^® Dynamic Master Portfolios’Forms N-Q may also be obtained upon request and without charge by calling (800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the LifePath^® Dynamic Funds/LifePath^® Dynamic Master Portfolios use to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling(800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how each LifePath^® Dynamic Fund/LifePath^® Dynamic Master Portfolio voted proxies relating to securities held in each LifePath^® Dynamic Fund’s/LifePath^® Dynamic Master Portfolio’s portfolio during the most recent 12-month period ended June 30 is available upon request and without charge (1) atblackrock.com; or by calling (800) 441-7762; and (2) on the SEC’s website at sec.gov.

BlackRock’s Mutual Fund Family

BlackRock offers a diverse lineup of open-end mutual funds crossing all investment styles and managed by experts in equity, fixed-income and tax-exempt investing. Visitblackrock.com for more information.

Shareholder Privileges

Account Information

Call us at (800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visitblackrock.com for more information.

Automatic Investment Plans

Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.

Systematic Withdrawal Plans

Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.

Retirement Plans

Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.

ADDITIONAL INFORMATION 103

Additional Information  (continued)

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding their non-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal non-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose to non-affiliated third parties any non-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. These non-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to non-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the non-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

Glossary of Terms Used in this Report

Currency
CAD	Canadian Dollar
EUR	Euro
USD	U.S. Dollar
Portfolio Abbreviations
ETF	Exchange-Traded Fund
MSCI	Morgan Stanley Capital International
S&P	Standard and Poor’s

104 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of a LifePath^® Dynamic Fund unless preceded or accompanied by the LifePath^® Dynamic Fund’s current prospectus. Past performance results shown in this report should not be considered a representation of future performance. Investment returns and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Statements and other information herein are as dated and are subject to change.

LPincre-12/19-AR

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· iShares MSCI Total International Index Fund

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call(800) 441-7762 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: (i) accessing the BlackRock website at blackrock.com/edelivery and logging into your accounts, if you hold accounts directly with BlackRock, or (ii) contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summary		4
About Fund Performance		6
Disclosure of Expenses		6
Derivative Financial Instruments		6
Fund Financial Statements:
Statement of Assets and Liabilities		7
Statement of Operations		8
Statements of Changes in Net Assets		9
Fund Financial Highlights		10
Fund Notes to Financial Statements		13
Fund Report of Independent Registered Public Accounting Firm		17
Important Tax Information		17
Master Portfolio Information		18
Master Portfolio Financial Statements:
Schedule of Investments		19
Statement of Assets and Liabilities		39
Statement of Operations		40
Statements of Changes in Net Assets		41
Master Portfolio Financial Highlights		42
Master Portfolio Notes to Financial Statements		43
Master Portfolio Report of Independent Registered Public Accounting Firm		50
Statement Regarding Liquidity Risk Management Program		51
Trustee and Officer Information		52
Additional Information		56
Glossary of Terms Used in this Report		57

3

Fund Summary  as of December 31, 2019 iShares MSCI Total International Index Fund

Investment Objective

iShares MSCI Total International Index Fund’s (the “Fund”) investment objective is to match the performance of the MSCI All Country World Index ex USA Index (the “MSCI ACWI ex USA Index”) in U.S. dollars with net dividends as closely as possible before the deduction of Fund expenses.

Portfolio Management Commentary

How did the Fund perform?

For the12-month period ended December 31, 2019, the Fund’s Institutional Shares returned 21.18%, Investor A Shares returned 20.80% and Class K Shares returned 21.22%. The benchmark MSCI ACWI ex USA Index returned 21.51% for the same period.

The Fund invests all of its assets in Total International ex U.S. Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio.

Describe the market environment.

In the first quarter of 2019, eurozone equity markets all advanced but to varying degrees as the recovery in equity market sentiment from 2018 lows occurred despite slowing economic activity across the region. Partially contributing to the bullish sentiment was the European Central Bank’s (“ECB”) reaffirmation of accommodative monetary policy and announcement of a new round of targeted longer-term refinancing operations. Within the eurozone, Germany underperformed amid continued weakness in the manufacturing and export sectors. Elsewhere in the eurozone, Italy outperformed major European countries despite two consecutive quarters of real gross domestic product contraction and political uncertainty as first quarter macro trends were relatively constructive.

In Asia-Pacific, Japan underperformed as uncertainty around U.S. trade protectionism, an upcomingsales-tax hike, and low levels of growth weighed on sentiment. Still, continued monetary support by the Bank of Japan and a globalrisk-on appetite benefited the country’s equity market. The yen fell 3.7% from intra-quarter highs, a tailwind for export names. Elsewhere, Hong Kong rallied amid a rebound in mainland Chinese sentiment.

In the second quarter of 2019, European equity markets contributed strong returns. Sentiment in the region was also supported by accommodative monetary policy, the increased expectations of further stimulus, higher than normal capacity utilization rates, and labor markets near full employment. Within the eurozone, Germany and France outperformed while Finland and Luxembourg underperformed.

Australia outperformed in the Asia-Pacific region as a decline in economic growth was driven by a June rate cut. Japan underperformed the benchmark but registered in positive territory as investors balancedrisk-on bids for the yen, trade tensions, and declining export volumes.

In the third quarter of 2019, within the eurozone, Germany underperformed while Belgium was the best-performing country in the eurozone due to an outsized gain in materials giant Umicore. Eurozone economic activity showed signs of synchronized deceleration. This prompted an aggressive response from the ECB, which announced a stimulus package that included a rate cut, resumption of quantitative easing, and atwo-tier excess liquidity system for banks. Simultaneously, the ECB cut both its growth and inflation forecasts, and lowered its forward guidance. In the United Kingdom, continued Brexit uncertainty drove volatility throughout the quarter ahead of the October 31 deadline. Parliament passed legislation that forced the government to ask for an extension if it could not reach a deal with the European Union (“EU”), which buoyed the sterling. Separately, the Bank of England remained on hold despite economic weakness.

In Asia-Pacific, Japanese equities outperformed despite deteriorating economic conditions and an impendingsales-tax hike. However, Japanese President Abe and U.S. President Donald Trump reached a limited trade agreement that removed the threat of tariffs on Japan’s auto exports for the time being. Elsewhere, Hong Kong underperformed amid mounting political unrest.

By the fourth quarter of 2019, the United Kingdom outperformed amid a dense quarter of Brexit developments. Prime Minister Boris Johnson was able to agree to a new Brexit deal with the EU in October, but the October 31 deadline was pushed back to January 31, 2020 due to a stalemate in Parliament. On continental Europe, both France and Germany performed well. Economic activity in Europe was better than in recent quarters, with the perceived easing in trade tensions — both between the United States and China, and the United States and EU — contributing to positive sentiment. Monetary policy remained accommodative, and the ECB resumed balance sheet expansion. Despite the easy monetary policy, the incremental increase in economic activity helped foster positive expectations.

In Asia-Pacific, Japan, Hong Kong and Australia recorded positive gains but ongoing tensions in Hong Kong and unimpressive growth out of China weighed on the region.

Describe recent portfolio activity.

During the12-month period, as changes were made to the composition of the MSCI ACWI ex USA Index, the Master Portfolio purchased and sold securities to maintain its objective of replicating the risks and return of the benchmark index.

Describe portfolio positioning at period end.

The Master Portfolio remains positioned to match the risk characteristics of its benchmark index, irrespective of the market’s future direction.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) iShares MSCI Total International Index Fund

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Commencement of operations.

^(b)  Assuming transaction costs and other operating expenses, including administration fees, if any.

^(c)  The Fund invests all of its assets in the Master Portfolio. The Master Portfolio will be substantially invested in equity securities in the MSCI ACWI ex USA Index, and will invest, under normal circumstances, at least 80% of its assets in securities or other financial instruments that are components of or have economic characteristics similar to the securities included in the MSCI ACWI ex USA Index.

^(d)  The index is a free float-adjusted market capitalization index designed to measure the combined equity market performance of developed and emerging market countries, excluding the United States.

Performance Summary for the Period Ended December 31, 2019

	6-Month Total Returns			Average Annual Total Returns (a)
				1 Year			5 Years			Since Inception (b)
Institutional		6.84	%		21.18	%		5.48	%		3.63	%
Investor A		6.61			20.80			5.23			3.35
Class K		6.77			21.22			5.53			3.92
MSCI ACWI ex USA Index		6.96			21.51			5.51			4.10

^(a)  See “About Fund Performance” on page 6 for a detailed description of share classes, including any related sales charges and fees.

^(b)  The Fund commenced operations on June 30, 2011.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

Expense Example

	Actual						Hypothetical (b)
	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
Institutional	$	1,000.00	$	1,068.40	$	0.83	$	1,000.00	$	1,024.40	$	0.82		0.16	%
Investor A		1,000.00		1,066.10		2.14		1,000.00		1,023.14		2.09		0.41
Class K		1,000.00		1,067.70		0.57		1,000.00		1,024.65		0.56		0.11

^(a)  For each class of the Fund, expenses are equal to the annualized net expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period shown). Because the Fund invests all of its assets in the Master Portfolio, the expense example reflects the net expenses of both the Fund and the Master Portfolio in which it invests.

^(b)  Hypothetical 5% annual return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

See “Disclosure of Expenses” on page 6 for further information on how expenses were calculated.

FUND SUMMARY 5

About Fund Performance

Institutional and Class K Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors.

Investor A Shares are not subject to any sales charge and bear no ongoing distribution fee. These shares are subject to an ongoing service fee of 0.25% per year. These shares are generally available through financial intermediaries.

Performance information reflects past performance and does not guarantee future results. Current performance may be lower or higher than the performance data quoted. Refer toblackrock.com to obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Figures shown in the performance table on the previous page assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend date. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of service, distribution and transfer agency fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (the “Administrator”), the Fund’s administrator, has contractually and/or voluntarily agreed to waive and/or reimburse a portion of the Fund’s expenses. Without such waiver and/or reimbursement, the Fund’s performance would have been lower. With respect to the Fund’s voluntary waiver, the Administrator is under no obligation to waive and/or reimburse or to continue waiving and/or reimbursing its fees and such voluntary waiver may be reduced or discontinued at any time. With respect to the Fund’s contractual waiver, the Administrator is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See Note 4 of the Notes to Financial Statements for additional information on waivers and/or reimbursements.

Disclosure of Expenses

Shareholders of the Fund may incur the following charges: (a) transactional expenses; and (b) operating expenses, including administration fees, service and distribution fees, including12b-1 fees, acquired fund fees and expenses, and other fund expenses. The expense example on the previous page (which is based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019) is intended to assist shareholders both in calculating expenses based on an investment in the Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense example provides information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their share class under the heading entitled “Expenses Paid During the Period.”

The expense example also provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in the Fund and other funds, compare the 5% hypothetical example with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense example are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical example is useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

Derivative Financial Instruments

The Master Portfolio may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The Master Portfolio’s successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation the Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The Master Portfolio’s investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	iShares MSCI Total International Index Fund
ASSETS
Investments at value — Master Portfolio	$	1,094,893,879
Receivables:
Capital shares sold		4,154,112
From the Administrator/Manager		11,224
Prepaid expenses		34,421
Total assets		1,099,093,636
LIABILITIES
Payables:
Administration fees		18,706
Capital shares redeemed		846,156
Contributions to the Master		3,307,955
Officer’s fees		289
Other accrued expenses		100,815
Professional fees		19,098
Recoupment of past waived fees		1,239
Service fees		70,890
Total liabilities		4,365,148
NET ASSETS	$	1,094,728,488
NET ASSETS CONSIST OF
Paid-in capital	$	978,648,150
Accumulated earnings		116,080,338
NET ASSETS	$	1,094,728,488
Institutional — Based on net assets of $264,844,771 and 28,327,958 shares outstanding, unlimited shares authorized, no par value	$	9.35
Investor A — Based on net assets of $341,385,257 and 36,617,661 shares outstanding, unlimited shares authorized, no par value	$	9.32
Class K — Based on net assets of $488,498,460 and 50,680,902 shares outstanding, unlimited shares authorized, no par value	$	9.64

See notes to financial statements.

FINANCIAL STATEMENTS 7

Statement of Operations

Year Ended December 31, 2019

	iShares MSCI Total International Index Fund
INVESTMENT INCOME
Net investment income allocated from the Master portfolio:
Dividends — affiliated	$	149,053
Dividends — unaffiliated		29,737,742
Securities lending income — affiliated — net		276,400
Non-cash dividends — unaffiliated		2,243,962
Foreign taxes withheld		(3,193,759	)
Expenses		(701,942	)
Fees waived		4,969
Total investment income		28,516,425
FUND EXPENSES
Service — class specific		743,992
Transfer agent — class specific		283,841
Administration		89,930
Registration		89,012
Professional		73,815
Printing		28,138
Accounting services		5,088
Recoupment of past fees waived and/or reimbursed		1,463
Recoupment of past waived and/or reimbursed fees — class specific		1,239
Officer		408
Miscellaneous		9,784
Total expenses excluding interest expense and fees		1,326,710
Total expenses		1,326,710
Less:
Fees waived and/or reimbursed by the Administrator/Manager		(24,859	)
Transfer agent fees waived and/or reimbursed — class specific		(17,806	)
Total expenses after fees waived and/or reimbursed		1,284,045
Net investment income		27,232,380
REALIZED AND UNREALIZED GAIN (LOSS) ALLOCATED FROM THE MASTER PORTFOLIO
Net realized gain (loss) from:
Futures contracts		1,424,606
Foreign currency transactions		(65,482	)
Investments — affiliated		13,030
Investments — unaffiliated (including $6,808 foreign capital gain tax)		(6,953,793	)
		(5,581,639	)
Net change in unrealized appreciation (depreciation) on:
Futures contracts		119,023
Foreign currency translations		(6,982	)
Investments — affiliated		1,944
Investments — unaffiliated (including $(39,310) foreign capital gain tax)		149,109,188
		149,223,173
Net realized and unrealized gain		143,641,534
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	170,873,914

See notes to financial statements.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	iShares MSCI Total International Index Fund
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	27,232,380		$	20,101,654
Net realized loss		(5,581,639	)		(8,196,059	)
Net change in unrealized appreciation (depreciation)		149,223,173			(126,817,664	)
Net increase (decrease) in net assets resulting from operations		170,873,914			(114,912,069	)
DISTRIBUTIONS(a)
From net investment income and net realized gain:
Institutional		(7,053,977	)		(4,324,279	)
Investor A		(8,998,745	)		(7,142,713	)
Class K		(12,934,902	)		(7,792,686	)
From return of capital:
Institutional		—			(355,156	)
Investor A		—			(586,636	)
Class K		—			(640,019	)
Decrease in net assets resulting from distributions to shareholders		(28,987,624	)		(20,841,489	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		221,905,970			241,322,260
NET ASSETS
Total increase in net assets		363,792,260			105,568,702
Beginning of year		730,936,228			625,367,526
End of year	$	1,094,728,488		$	730,936,228

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 9

Financial Highlights

(For a share outstanding throughout each period)

	iShares MSCI Total International Index Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	7.97		$	9.54		$	7.70		$	7.65		$	8.43
Net investment income(a)		0.27			0.26			0.24			0.21			0.21
Net realized and unrealized gain (loss)		1.40			(1.56	)		1.86			0.12			(0.69	)
Net increase (decrease) from investment operations		1.67			(1.30	)		2.10			0.33			(0.48	)
Distributions(b)
From net investment income		(0.29	)		(0.25	)		(0.26	)		(0.21	)		(0.17	)
From net realized gain		—			—			(0.00	)(c)		(0.07	)		(0.13	)
From return of capital		—			(0.02	)		—			—			—
Total distributions		(0.29	)		(0.27	)		(0.26	)		(0.28	)		(0.30	)
Net asset value, end of year	$	9.35		$	7.97		$	9.54		$	7.70		$	7.65
Total Return(d)
Based on net asset value		21.18	%		(13.94	)%		27.57	%		4.31	%		(5.89	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.16	(g)		0.17	%(g)		0.16	%		0.19	%		0.45	%
Total expenses after fees waived and/or reimbursed and paid indirectly		0.16	%		0.16	%		0.16	%		0.16	%		0.17	%
Net investment income		3.08	%		2.83	%		2.69	%		2.74	%		2.49	%
Supplemental Data
Net assets, end of year (000)	$	264,845		$	159,351		$	73,405		$	76,001		$	40,716
Portfolio turnover rate of the Master Portfolio		5	%		40	%		57	%		15	%		6	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(g)  Includes recoupment of past waived and/or reimbursed fees with no financial impact to the expense ratios.

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares MSCI Total International Index Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	7.95		$	9.52		$	7.68		$	7.63		$	8.41
Net investment income(a)		0.25			0.23			0.22			0.19			0.13
Net realized and unrealized gain (loss)		1.39			(1.56	)		1.86			0.12			(0.62	)
Net increase (decrease) from investment operations		1.64			(1.33	)		2.08			0.31			(0.49	)
Distributions(b)
From net investment income		(0.27	)		(0.22	)		(0.24	)		(0.19	)		(0.16	)
From net realized gain		—			—			(0.00	)(c)		(0.07	)		(0.13	)
From return of capital		—			(0.02	)		—			—			—
Total distributions		(0.27	)		(0.24	)		(0.24	)		(0.26	)		(0.29	)
Net asset value, end of year	$	9.32		$	7.95		$	9.52		$	7.68		$	7.63
Total Return(d)
Based on net asset value		20.80	%		(14.19	)%		27.32	%		4.07	%		(6.05	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.41	%(g)		0.42	%(g)		0.41	%		0.46	%		0.43	%
Total expenses after fees waived and/or reimbursed and paid indirectly		0.41	%		0.41	%		0.41	%		0.41	%		0.38	%
Net investment income		2.84	%		2.55	%		2.47	%		2.48	%		1.63	%
Supplemental Data
Net assets, end of year (000)	$	341,385		$	272,066		$	288,431		$	247,732		$	144,177
Portfolio turnover rate of the Master Portfolio		5	%		40	%		57	%		15	%		6	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(g)  Includes recoupment of past waived and/or reimbursed fees with no financial impact to the expense ratios.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 11

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares MSCI Total International Index Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	8.21		$	9.82		$	7.92		$	7.86		$	8.65
Net investment income(a)		0.28			0.27			0.25			0.21			0.23
Net realized and unrealized gain (loss)		1.44			(1.61	)		1.91			0.13			(0.71	)
Net increase (decrease) from investment operations		1.72			(1.34	)		2.16			0.34			(0.48	)
Distributions(b)
From net investment income		(0.29	)		(0.25	)		(0.26	)		(0.21	)		(0.18	)
From net realized gain		—			—			(0.00	)(c)		(0.07	)		(0.13	)
From return of capital		—			(0.02	)		—			—			—
Total distributions		(0.29	)		(0.27	)		(0.26	)		(0.28	)		(0.31	)
Net asset value, end of year	$	9.64		$	8.21		$	9.82		$	7.92		$	7.86
Total Return(d)
Based on net asset value		21.22	%		(13.91	)%		27.62	%		4.37	%		(5.83	)%
Ratios to Average Net Assets(e)(f)
Total expenses		0.11	%		0.12	%(g)		0.11	%		0.14	%		0.46	%
Total expenses after fees waived and/or reimbursed and paid indirectly		0.11	%		0.11	%		0.11	%		0.11	%		0.13	%
Net investment income		3.15	%		2.85	%		2.75	%		2.68	%		2.71	%
Supplemental Data
Net assets, end of year (000)	$	488,498		$	299,520		$	263,532		$	103,498		$	7,297
Portfolio turnover rate of the Master Portfolio		5	%		40	%		57	%		15	%		6	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(g)  Includes recoupment of past waived and/or reimbursed fees with no financial impact to the expense ratios.

See notes to financial statements.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. iShares MSCI Total International Index Fund (the “Fund”) is a series of the Trust. The Fund is classified as diversified.

The Fund seeks to achieve its investment objective by investing all of its assets in Total International ex U.S. Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio (“MIP”), an affiliate of the Trust, which has the same investment objective and strategies as the Fund. The value of the Fund’s investment in the Master Portfolio reflects the Fund’s proportionate interest in the net assets of the Master Portfolio. The performance of the Fund is directly affected by the performance of the Master Portfolio. At December 31, 2019, the percentage of the Master Portfolio owned by the Fund was 99.9%. The financial statements of the Master Portfolio, including the Schedule of Investments, are included elsewhere in this report and should be read in conjunction with the Fund’s financial statements.

The Fund offers multiple classes of shares. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that Investor A Shares bear expenses related to the shareholder servicing and distribution of such shares. Institutional and Class K Shares are sold only to certain eligible investors. Investor A Shares are generally available through financial intermediaries. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures.

The Board of Trustees of the Trust and Board of Trustees of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

Share Class	Initial Sales Charge	CDSC		Conversion Privilege
Institutional and Class K Shares	No		No	None
Investor A Shares	No		No	None

The Fund, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from the Master Portfolio are accounted for on a trade date basis. The Fund records its proportionate share of the Master Portfolio’s income, expenses and realized and unrealized gains and losses on a daily basis. Realized and unrealized gains and losses are adjusted utilizing partnership tax allocation rules. In addition, the Fund accrues its own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions paid by the Fund are recorded on theex-dividend date. Distributions of capital gains are recorded on theex-dividend date and made at least annually. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

Indemnifications:In the normal course of business, the Fund enters into contracts that contain a variety of representations that provide general indemnification. The Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to the Fund or its classes are charged to that Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by the Administrator, are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the Fund and other shared expenses prorated to the Fund are allocated daily to each class based on its relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Fund’s policy is to value its financial instruments at fair value. The Fund records its investment in the Master Portfolio at fair value based on the Fund’s proportionate interest in the net assets of the Master Portfolio. Valuation of securities held by the Master Portfolio is discussed in Note 3 of the Master Portfolio’s Notes to Financial Statements, which are included elsewhere in this report.

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration:The Trust, on behalf of the Fund, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL” or the “Administrator”), an indirect, wholly-owned subsidiary of BlackRock, Inc (“BlackRock”), to provide administrative services (other than investment advice and related portfolio activities). For such services, the Fund pays the Administrator a monthly fee at an annual rate of 0.01% of the average daily net assets of the Fund. The Fund does not pay an investment advisory fee or investment management fee.

NOTESTO FINANCIAL STATEMENTS 13

Notes to Financial Statements  (continued)

Service Fees:The Trust, on behalf of the Fund, entered into a Distribution Agreement and a Distribution and Service Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Pursuant to the Distribution and Service Plan and in accordance with Rule12b-1 under the 1940 Act, the Fund pays BRIL ongoing service fees. The fees are accrued daily and paid monthly at annual rates of 0.25% based upon the average daily net assets of Investor A Shares.

BRIL and broker-dealers, pursuant tosub-agreements with BRIL, provide shareholder servicing services to the Fund. The ongoing service fee compensates BRIL and each broker-dealer for providing shareholder servicing related services to shareholders.

For the year ended December 31, 2019, the class specific service fees borne directly by Investor A Shares was $743,992.

Transfer Agent: Pursuant to written agreements, certain financial intermediaries, some of which may be affiliates, provide the Fund withsub-accounting, recordkeeping,sub-transfer agency and other administrative services with respect to servicing of underlying investor accounts. For these services, these entities receive an asset-based fee or an annual fee per shareholder account, which will vary depending on share class and/or net assets. For the year ended December 31, 2019, the Fund did not pay any amounts to affiliates in return for these services.

The Administrator maintains a call center that is responsible for providing certain shareholder services to the Fund. Shareholder services include responding to inquiries and processing purchases and sales based upon instructions from shareholders. For the year ended December 31, 2019, the Fund reimbursed the Administrator the following amounts for costs incurred in running the call center, which are included in transfer agent — class specific in the Statement of Operations:

Institutional		Investor A		Class K		Total
$	426	$	2,160	$	1,205	$	3,791

For the year ended December 31, 2019, the following table shows the class specific transfer agent fees borne directly by each share class of the Fund:

Institutional		Investor A		Class K		Total
$	108,217	$	160,379	$	15,245	$	283,841

Expense Limitations, Waivers, Reimbursements, and Recoupments:With respect to the Fund, the Administrator/Manager contractually agreed to waive and/or reimburse fees or expenses in order to limit expenses, excluding interest expense, dividend expense, tax expense, acquired fund fees and expenses, and certain other fund expenses, which constitute extraordinary expenses not incurred in the ordinary course of the Fund’s business (“expense limitation”). The expense limitations as a percentage of average daily net assets are as follows:

Institutional		Investor A		Class K
	0.16%		0.41%		0.11%

The Administrator/Manager has agreed not to reduce or discontinue these contractual expense limitations through April 30, 2020, unless approved by the Board, including a majority of the trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”), or by a vote of a majority of the outstanding voting securities of the Fund. For the year ended December 31, 2019, the Administrator/Manager waived and/or reimbursed $24,859, which is included in fees waived and/or reimbursed by the Administrator/Manager in the Statement of Operations.

These amounts waived and/or reimbursed are included in transfer agent fees waived and/or reimbursed — class specific, in the Statement of Operations. For the year ended December 31, 2019, class specific expense waivers and/or reimbursements are as follows:

Institutional		Investor A		Class K		Total
$	1,813	$	7,018	$	8,975	$	17,806

With respect to the contractual expense limitation, if during the Fund’s fiscal year the operating expenses of a share class, that at any time during the prior two fiscal years received a waiver and/or reimbursement from the Administrator/Manager, are less than the current expense limitation for that share class, the Administrator/Manager is entitled to be reimbursed by such share class up to the lesser of: (a) the amount of fees waived and/or expenses reimbursed during those prior two fiscal years under the agreement and (b) an amount not to exceed either the current expense limitation of that share class or the expense limitation of the share class in effect at the time that the share class received the applicable waiver and/or reimbursement, provided that:

(1) the Fund, of which the share class is a part, has more than $50 million in assets for the fiscal year; and

(2) BFA, BAL or an affiliate continues to serve as the Fund’s investment adviser or administrator.

This repayment applies only to the contractual expense limitation on net expenses and does not apply to any voluntary waivers that may be in effect from time to time. Effective December 1, 2019, the repayment arrangement between the Fund and the Administrator/Manager pursuant to which such Fund may be required to repay amounts waived and/or reimbursed under the Fund’s contractual caps on net expenses was terminated.

For the year ended December 31, 2019, the Administrator/Manager recouped the following fund level and class specific waivers and/or reimbursements previously recorded by the Fund:

Fund Level	$	1,463
Institutional		960
Investor A		279

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

The following fund level and class specific waivers and/or reimbursements previously recorded by the Fund, which were subject to recoupment by the Administrator/Manager, expired on December 1, 2019:

Fund Level	$	71,640
Institutional		2,516
Investor A		18,418
Class K		16,848

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), the Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Fund’s investment policies and restrictions. The Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33¹⁄₃% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Fund did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock or its affiliates. The Fund reimburses the Administrator for a portion of the compensation paid to the Fund’s Chief Compliance Officer, which is included in Trustees and Officers in the Master Portfolio’s Statement of Operations.

5. INCOME TAX INFORMATION

It is the Fund’s policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

The Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Fund as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Fund’s financial statements.

The tax character of distributions paid was as follows:

	12/31/19		12/31/18
Ordinary income	$	28,987,624	$	19,259,678
Long-term capital gains		—		1,581,811
	$	28,987,624	$	20,841,489

As of period end, the tax components of accumulated earnings were as follows:

Undistributed ordinary income	$	784,607
Non-expiring Capital loss carryforwards(a)		(13,184,931	)
Net unrealized gains(b)		128,480,662
	$	116,080,338

^(a)  Amounts available to offset future realized capital gains.

^(b)  The difference between book-basis andtax-basis net unrealized gains (losses) was attributable primarily to the timing and recognition of partnership income.

NOTESTO FINANCIAL STATEMENTS 15

Notes to Financial Statements  (continued)

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended 12/31/19						Year Ended 12/31/18
	Shares			Amount			Shares			Amount
Institutional
Shares sold		13,301,414		$	116,421,815			14,775,372		$	139,725,049
Shares issued in reinvestment of distributions		795,852			7,052,234			526,753			4,679,435
Shares redeemed		(5,760,973	)		(50,944,221	)		(3,001,136	)		(26,888,330	)
Net increase		8,336,293		$	72,529,828			12,300,989		$	117,516,154
Investor A
Shares sold		18,188,679		$	160,062,788			10,003,964		$	90,378,609
Shares issued in reinvestment of distributions		1,018,406			8,995,577			871,034			7,729,271
Shares redeemed		(16,812,998	)		(147,579,863	)		(6,951,395	)		(63,361,367	)
Net increase		2,394,087		$	21,478,502			3,923,603		$	34,746,513
Class K
Shares sold		28,436,533		$	256,695,981			20,658,870		$	190,435,209
Shares issued in reinvestment of distributions		1,415,561			12,927,470			921,785			8,430,275
Shares redeemed		(15,654,910	)		(141,725,811	)		(11,927,432	)		(109,805,891	)
Net increase		14,197,184		$	127,897,640			9,653,223		$	89,059,593
Total Net Increase		24,927,564		$	221,905,970			25,877,815		$	241,322,260

7. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Fund through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm iShares MSCI Total International Index Fund

To the Board of Trustees of

BlackRock Funds III and Shareholders of iShares MSCI Total International Index Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of iShares MSCI Total International Index Fund (one of the series constituting BlackRock Funds III, referred to hereafter as the “Fund”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolio. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

Important Tax Information  (Unaudited)

During the fiscal year ended December 31, 2019, the following information is provided with respect to the ordinary income distributions paid by the Fund:

	Payable Date
Qualified Dividend Income for Individuals(a)(b)	Quarterly		86.25%
Foreign Source Income(a)(b)	Quarterly		93.40
Foreign Taxes Paid Per Share(c)	03/29/2019	$	0.005259
	07/01/2019		0.009223
	09/30/2019		0.005869
	12/13/2019		0.006064

^(a)  The Fund hereby designates the percentage indicated above or the maximum amount allowable by law.

^(b)  Expressed as a percentage of distributions grossed-up for foreign taxes.

^(c)  The foreign taxes paid represent taxes incurred by the Fund on income received by the Fund from foreign sources. Foreign taxes paid may be included in taxable income with an offsetting deduction from gross income or may be taken as a credit for taxes paid to foreign governments. You should consult your tax advisor regarding the appropriate treatment of foreign taxes paid.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM / IMPORTANT TAX INFORMATION 17

Master Portfolio Information  as of December 31, 2019 Total International ex U.S. Index Master Portfolio

TEN LARGEST HOLDINGS

Security	Percent of Net Assets
Alibaba Group Holding Ltd. — ADR		2	%
Nestle SA, Registered Shares		1
Tencent Holdings Ltd.		1
Taiwan Semiconductor Manufacturing Co. Ltd.		1
Samsung Electronics Co. Ltd.		1
Roche Holding AG		1
Novartis AG, Registered Shares		1
Toyota Motor Corp.		1
HSBC Holdings PLC		1
SAP SE		1

GEOGRAPHIC ALLOCATION

Country/Geographic Region	Percent of Net Assets
Japan		16	%
China		9
United Kingdom		9
France		7
Canada		7
Switzerland		6
Germany		6
Australia		5
Taiwan		3
South Korea		3
United States		3
Netherlands		3
India		2
Hong Kong		2
Brazil		2
Spain		2
Sweden		2
South Africa		1
Italy		1
Denmark		1
Russia		1
Singapore		1
Finland		1
Saudi Arabia		1
Thailand		1
Belgium		1
Mexico		1
Other(a)		4
Liabilities in Excess of Other Assets		(1	)

^(a)  Others include Argentina, Austria, Chile, Colombia, Czech Republic, Egypt, Greece, Hungary, Indonesia, Ireland, Luxembourg, Macau, Malaysia, New Zealand, Norway, Pakistan, Peru, Philippines, Poland, Portugal, Qatar, Romania, Turkey, United Arab Emirates, Zambia.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Common Stocks — 97.3%
Argentina — 0.0%
Banco Macro SA — ADR(a)		2,190	$	79,387
Globant SA(b)		1,394		147,834
Grupo Financiero Galicia SA — ADR		4,253		69,026
Telecom Argentina SA — ADR		6,259		71,040
YPF SA, ADR(a)		7,500		86,850
				454,137
Australia — 4.9%
AGL Energy Ltd.(a)		29,297		421,689
Alumina Ltd.		105,749		170,806
AMP Ltd.(b)		199,787		268,753
APA Group(c)		54,780		426,432
Aristocrat Leisure Ltd.		27,117		640,752
ASX Ltd.		9,515		523,897
Aurizon Holdings Ltd.		84,172		308,905
AusNet Services		88,260		105,249
Australia & New Zealand Banking Group Ltd.		134,951		2,327,361
Bendigo & Adelaide Bank Ltd.		30,340		208,188
BHP Group Ltd.		140,709		3,852,936
BHP Group PLC		101,435		2,377,019
BlueScope Steel Ltd.		28,378		300,568
Boral Ltd.		49,450		155,574
Brambles Ltd.		80,108		659,345
Caltex Australia Ltd.		15,374		366,583
Challenger Ltd.		38,501		219,091
CIMIC Group Ltd.		6,446		149,867
Coca-Cola Amatil Ltd.		30,008		233,032
Cochlear Ltd.		3,172		499,926
Coles Group Ltd.		57,036		593,731
Commonwealth Bank of Australia		84,147		4,720,462
Computershare Ltd.		21,967		258,989
Crown Resorts Ltd.		17,839		150,404
CSL Ltd.		21,519		4,172,148
Dexus		50,184		413,104
Flight Centre Travel Group Ltd.		4,600		142,278
Fortescue Metals Group Ltd.		62,711		472,738
Goodman Group		79,850		750,365
GPT Group		85,677		337,485
Harvey Norman Holdings Ltd.		16,035		45,798
Incitec Pivot Ltd.		66,272		148,057
Insurance Australia Group Ltd.		100,648		540,793
Lendlease Group(c)		31,390		388,091
Macquarie Group Ltd.		15,487		1,499,827
Magellan Financial Group Ltd.		5,653		226,487
Medibank Pvt Ltd.		110,102		244,010
Mirvac Group		177,414		397,105
National Australia Bank Ltd.		139,035		2,405,875
Newcrest Mining Ltd.		38,073		804,063
Oil Search Ltd.		55,471		282,849
Orica Ltd.		17,936		276,582
Origin Energy Ltd.		88,740		526,161
Qantas Airways Ltd.		30,338		151,220
QBE Insurance Group Ltd.		63,379		572,722
Ramsay Health Care Ltd.		6,831		347,546
REA Group Ltd.		2,994		217,504
Rio Tinto Ltd.		17,287		1,223,055
Rio Tinto PLC		54,938		3,252,053
Santos Ltd.		95,293		548,217
Scentre Group		239,323		644,079
SEEK Ltd.		14,013		221,793
Sonic Healthcare Ltd.		18,219		367,348
South32 Ltd.		233,710		441,272
Stockland		120,177		389,922

Security	Shares		Value
Australia (continued)
Suncorp Group Ltd.		58,287	$	529,469
Sydney Airport(c)		56,475		343,126
Tabcorp Holdings Ltd.		86,499		274,989
Telstra Corp. Ltd.		208,621		518,213
TPG Telecom Ltd.		14,159		66,713
Transurban Group(c)		127,671		1,336,338
Treasury Wine Estates Ltd.		31,088		354,115
Vicinity Centres		183,891		321,637
Washington H Soul Pattinson & Co. Ltd.		6,150		92,779
Wesfarmers Ltd.		54,217		1,575,639
Westpac Banking Corp.		169,652		2,897,102
WiseTech Global Ltd.(a)		7,407		121,639
Woodside Petroleum Ltd.		44,033		1,064,656
Woolworths Group Ltd.		59,429		1,507,325
Worley Ltd.		15,561		168,098
				53,561,944
Austria — 0.2%
ANDRITZ AG		2,807		120,674
Erste Group Bank AG(b)		15,773		592,468
OMV AG		7,068		395,983
Raiffeisen Bank International AG		8,941		223,788
Verbund AG		2,859		143,478
voestalpine AG		5,074		140,731
				1,617,122
Belgium — 0.7%
Ageas		9,147		540,886
Anheuser-Busch InBev SA		36,695		3,005,334
Colruyt SA		2,435		126,953
Galapagos NV(b)		2,147		447,107
Groupe Bruxelles Lambert SA		4,191		442,238
KBC Group NV		12,684		956,305
Proximus SADP		7,301		209,201
Solvay SA		3,386		394,106
Telenet Group Holding NV		1,636		73,543
UCB SA		5,499		437,580
Umicore SA		9,298		453,129
				7,086,382
Brazil — 1.3%
Ambev SA		211,436		981,309
Atacadao SA		19,425		112,754
B2W Cia Digital(b)		13,505		211,033
B3 SA — Brasil Bolsa Balcao		95,765		1,022,950
Banco Bradesco SA		56,646		479,760
Banco BTG Pactual SA		8,514		161,128
Banco do Brasil SA		40,649		533,741
Banco Santander Brasil SA		23,639		290,999
BB Seguridade Participacoes SA		29,783		279,121
BR Malls Participacoes SA		45,055		202,275
BRF SA(b)		28,171		246,506
CCR SA		52,990		250,019
Centrais Eletricas Brasileiras SA		14,343		134,776
Centrais Eletricas Brasileiras SA(b)		2,936		27,589
Cia de Saneamento Basico do Estado de Sao Paulo		13,793		207,648
Cia Siderurgica Nacional SA		38,838		136,228
Cielo SA		56,040		116,602
Cogna Educacao		73,599		209,122
Cosan SA		9,178		158,728
Embraer SA(b)		41,883		205,422
Energisa SA		7,713		102,637
Engie Brasil Energia SA		15,208		192,052
Equatorial Energia SA		36,500		206,785
Hapvida Participacoes e Investimentos SA(d)		11,869		188,537
Hypera SA		19,300		171,233

SCHEDULE OF INVESTMENTS 19

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Brazil (continued)
IRB Brasil Resseguros S/A		30,111	$	291,551
Klabin SA		43,092		197,212
Localiza Rent a Car SA		21,807		257,014
Lojas Renner SA		38,017		531,030
Magazine Luiza SA		37,811		448,352
Multiplan Empreendimentos Imobiliarios SA		14,550		119,722
Natura & Co. Holding SA		16,400		157,652
Notre Dame Intermedica Participacoes SA		24,443		414,705
Petrobras Distribuidora SA		32,398		242,178
Petroleo Brasileiro SA		142,943		1,137,091
Porto Seguro SA		4,400		68,625
Raia Drogasil SA		9,300		258,098
Rumo SA(b)		53,100		344,522
Sul America SA		10,107		150,548
Suzano SA		31,864		314,307
TIM Participacoes SA		41,040		159,867
Ultrapar Participacoes SA		41,657		263,858
Vale SA		151,827		2,011,678
WEG SA		48,816		420,604
				14,617,568
Canada — 6.5%
Agnico Eagle Mines Ltd.		11,305		696,295
Air Canada(b)		5,891		220,070
Algonquin Power & Utilities Corp.(a)		17,953		253,973
Alimentation Couche-Tard, Inc., Class B		42,565		1,350,817
AltaGas Ltd.		10,053		153,131
Atco Ltd. Class I		3,829		146,756
Aurora Cannabis, Inc.(a)(b)		36,707		78,867
Bank of Montreal		30,963		2,399,689
Bank of Nova Scotia(a)		58,510		3,305,001
Barrick Gold Corp.		86,020		1,597,784
BCE, Inc.		7,099		328,887
BlackBerry Ltd.(b)		22,301		143,401
Bombardier, Inc., Class B(b)		82,198		122,169
Brookfield Asset Management, Inc., Class A		43,055		2,487,711
CAE, Inc.		11,511		304,762
Cameco Corp.		18,780		166,895
Canadian Apartment Properties REIT		4,555		185,946
Canadian Imperial Bank of Commerce(a)		21,475		1,787,061
Canadian National Railway Co.		33,295		3,011,947
Canadian Natural Resources Ltd.		58,176		1,881,631
Canadian Pacific Railway Ltd.		6,852		1,746,731
Canadian Tire Corp. Ltd., Class A		3,022		325,228
Canadian Utilities Ltd., Class A		5,686		171,515
Canopy Growth Corp.(a)(b)		8,564		180,111
CCL Industries, Inc., Class B		6,846		291,649
Cenovus Energy, Inc.		48,424		492,239
CGI, Inc.(b)		12,610		1,055,276
CI Financial Corp.		11,467		191,713
Constellation Software, Inc.		1,002		973,149
Cronos Group, Inc.(a)(b)		7,439		57,115
Dollarama, Inc.		12,664		435,250
Emera, Inc.		12,252		526,386
Empire Co. Ltd., Class A		7,280		170,767
Enbridge, Inc.		97,031		3,857,927
Encana Corp.		66,055		309,279
Fairfax Financial Holdings Ltd.		1,310		615,116
First Capital Real Estate Investment Trust		10,928		173,949
Fortis, Inc.		20,994		871,092
Franco-Nevada Corp.		9,060		935,548
George Weston Ltd.		4,118		326,700
Gildan Activewear, Inc.		9,332		275,889
Great-West Lifeco, Inc.		13,282		340,194
H&R Real Estate Investment Trust		5,810		94,406

Security	Shares		Value
Canada (continued)
Husky Energy, Inc.		15,100	$	121,167
Hydro One Ltd.(d)		13,242		255,754
iA Financial Corp. Inc.		6,144		337,493
IGM Financial, Inc.		4,062		116,616
Imperial Oil Ltd.		11,421		302,115
Intact Financial Corp.		6,587		712,292
Inter Pipeline Ltd.(a)		18,400		319,384
Keyera Corp.		8,699		227,900
Kinross Gold Corp.(b)		75,016		355,857
Kirkland Lake Gold Ltd.		10,192		449,263
Loblaw Cos. Ltd.		8,981		463,384
Magna International, Inc.		13,924		763,458
Manulife Financial Corp.		95,208		1,932,681
Methanex Corp.		3,599		138,993
Metro, Inc.		11,614		479,299
National Bank of Canada		14,884		826,182
Nutrien Ltd.(a)		27,396		1,311,624
Onex Corp.		4,171		263,934
Open Text Corp.		14,028		618,137
Parkland Fuel Corp.		7,050		259,024
Pembina Pipeline Corp.(a)		25,186		933,504
Power Corp. of Canada		15,897		409,499
Power Financial Corp.(a)		12,359		332,543
PrairieSky Royalty Ltd.		13,775		161,560
Quebecor, Inc., Class B		7,073		180,508
Restaurant Brands International, Inc.		13,453		857,602
RioCan Real Estate Investment Trust		9,233		190,270
Rogers Communications, Inc., Class B		17,858		886,746
Royal Bank of Canada		67,441		5,336,385
Saputo, Inc.		10,865		336,354
Shaw Communications, Inc., Class B		21,778		441,916
Shopify, Inc., Class A(b)		4,807		1,911,250
SmartCentres Real Estate Investment Trust		4,313		103,661
Stars Group, Inc.(b)		12,831		334,868
Sun Life Financial, Inc.		29,672		1,352,955
Suncor Energy, Inc.		75,952		2,489,328
TC Energy Corp.		44,348		2,361,948
Teck Resources Ltd., Class B		21,176		367,243
TELUS Corp.		10,231		396,145
Thomson Reuters Corp.		10,771		770,489
Toronto-Dominion Bank		85,710		4,807,100
West Fraser Timber Co. Ltd.		3,334		147,065
Wheaton Precious Metals Corp.		19,152		569,892
WSP Global, Inc.		4,270		291,572
				71,264,982
Chile — 0.2%
Aguas Andinas SA, Class A		76,400		32,411
Antofagasta PLC		18,127		219,477
Banco de Chile		2,943,762		312,012
Banco de Credito e Inversiones SA		2,187		99,178
Banco Santander Chile		3,205,454		183,303
Cencosud SA		73,021		96,138
Cia Cervecerias Unidas SA		4,404		43,164
Colbun SA		466,420		74,434
Empresa Nacional de Telecomunicaciones SA(b)		2,032		14,452
Empresas CMPC SA		65,894		161,241
Empresas COPEC SA(b)		18,259		163,905
Enel Americas SA		1,752,619		389,238
Enersis Chile SA		1,771,049		166,047
Itau CorpBanca		2,375,874		13,776
Latam Airlines Group SA		10,650		121,504
Lundin Mining Corp.		21,717		129,778
SACI Falabella		39,547		170,452
				2,390,510

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
China — 9.5%
3SBio, Inc.(b)(d)		95,500	$	123,721
51job, Inc. — ADR(a)(b)		1,550		131,595
58.com, Inc. — ADR(b)		4,858		314,458
A-Living Services Co. Ltd.(d)		30,250		104,384
AAC Technologies Holdings, Inc.(a)		29,500		257,535
AECC Aviation Power Co. Ltd., Class A		24,600		76,716
Agile Group Holdings Ltd.(a)		76,000		114,206
Agricultural Bank of China Ltd., Class A		289,800		153,692
Agricultural Bank of China Ltd., Class H		1,123,000		494,301
Aier Eye Hospital Group Co. Ltd., Class A		21,320		121,347
Air China Ltd.		111,198		155,110
Air China Ltd., Class H		62,000		62,900
Alibaba Group Holding Ltd. — ADR(b)		80,930		17,165,253
Alibaba Health Information Technology Ltd.(b)		176,000		203,293
Aluminum Corp. of China Ltd., Class H(b)		164,000		56,203
Anhui Conch Cement Co. Ltd., Class A		17,700		139,446
Anhui Conch Cement Co. Ltd., Class H		45,500		331,519
ANTA Sports Products Ltd.		55,000		492,425
Autohome, Inc. — ADR(a)(b)		3,672		293,797
AviChina Industry & Technology Co. Ltd., Class H		116,000		52,273
BAIC Motor Corp. Ltd., Class H(d)		114,000		64,778
Baidu, Inc. — ADR(b)		13,126		1,659,126
Bank of Beijing Co. Ltd., Class A		100,100		81,743
Bank of China Ltd., Class A		111,600		59,192
Bank of China Ltd., Class H		3,803,000		1,625,699
Bank of Communications Co. Ltd., Class A		130,900		105,944
Bank of Communications Co. Ltd., Class H		323,700		230,016
Bank of Hangzhou Co. Ltd., Class A		70,800		93,247
Bank of Jiangsu Co. Ltd., Class A		79,800		83,097
Bank of Nanjing Co. Ltd., Class A		142,100		179,210
Bank of Ningbo Co. Ltd., Class A		25,600		103,710
Bank of Shanghai Co. Ltd., Class A		76,510		104,426
Baoshan Iron & Steel Co. Ltd., Class A		165,698		136,795
Baozun, Inc., ADR(b)		2,062		68,293
BBMG Corp.		260,700		139,799
BeiGene Ltd., ADR(a)(b)		2,025		335,664
Beijing Capital International Airport Co. Ltd., Class H		100,000		96,865
Beijing Enterprises Holdings Ltd.		21,000		96,360
Beijing Enterprises Water Group Ltd.(b)		232,000		117,343
Best, Inc., ADR(a)(b)		17,452		97,033
BOC Hong Kong Holdings Ltd.		186,500		647,421
BOE Technology Group Co. Ltd., Class A		158,600		103,720
Brilliance China Automotive Holdings Ltd.(a)		148,000		153,603
Budweiser Brewing Co. APAC Ltd.(b)(d)		72,800		245,709
BYD Co. Ltd., Class A		15,600		106,925
Byd Co. Ltd., Class H		30,000		149,620
BYD Electronic International Co. Ltd.		15,000		28,878
CGN Power Co. Ltd., Class H(d)		546,000		145,810
China Agri-Industries Holdings Ltd.		202,000		106,997
China Aoyuan Group Ltd.		76,000		124,012
China Cinda Asset Management Co. Ltd., Class H		360,000		81,829
China CITIC Bank Corp. Ltd., Class H		448,000		268,623
China Coal Energy Co. Ltd., Class H		250,000		99,213
China Communications Construction Co. Ltd., Class H		239,000		194,774
China Communications Services Corp. Ltd., Class H		138,000		100,600
China Conch Venture Holdings Ltd.		92,500		403,476
China Construction Bank Corp., Class A		83,600		86,908
China Construction Bank Corp., Class H		4,524,000		3,922,495
China Eastern Airlines Corp. Ltd., Class H(b)		176,000		97,514
China Education Group Holdings Ltd.(a)		58,000		75,954
China Everbright Bank Co. Ltd., Class A		215,300		136,507
China Everbright Bank Co. Ltd., Class H		299,000		138,872
China Everbright International Ltd.		146,629		117,582
China Everbright Ltd.(a)		52,000		97,116

Security	Shares		Value
China (continued)
China Evergrande Group		103,000	$	285,579
China Fortune Land Development Co. Ltd., Class A		35,000		144,507
China Galaxy Securities Co. Ltd., Class H		132,500		78,056
China Gas Holdings Ltd.		97,000		363,189
China Hongqiao Group Ltd.		133,000		80,210
China Huarong Asset Management Co. Ltd., Class H(a)(d)		320,000		50,544
China Huishan Dairy Holdings Co. Ltd.(b)(e)		109,840		211
China International Capital Corp. Ltd., Class H(d)		59,200		114,141
China International Travel Service Corp. Ltd., Class A		7,700		98,532
China Jinmao Holdings Group Ltd.		326,000		253,788
China Lesso Group Holdings Ltd.		39,000		50,038
China Life Insurance Co. Ltd., Class A		22,200		111,463
China Life Insurance Co. Ltd., Class H		346,000		962,453
China Literature Ltd.(a)(b)(d)		24,200		100,837
China Longyuan Power Group Corp. Ltd., Class H		126,000		79,681
China Medical System Holdings Ltd.		61,000		87,803
China Mengniu Dairy Co. Ltd.(b)		137,000		554,178
China Merchants Bank Co. Ltd., Class A		65,200		352,582
China Merchants Bank Co. Ltd., Class H		186,578		959,221
China Merchants Port Holdings Co. Ltd.		65,720		111,200
China Merchants Securities Co. Ltd., Class A		46,000		121,123
China Merchants Shekou Industrial Zone Holdings Co. Ltd., Class A		32,997		94,222
China Minsheng Banking Corp. Ltd., Class A(b)		159,000		144,213
China Minsheng Banking Corp. Ltd., Class H		367,680		277,882
China Mobile Ltd.		295,000		2,492,707
China Molybdenum Co. Ltd., Class H(a)		213,000		91,390
China National Building Material Co. Ltd., Class H		132,000		147,262
China National Nuclear Power Co. Ltd., Class A		102,500		73,679
China Oilfield Services Ltd., Class H		64,000		100,481
China Overseas Land & Investment Ltd.		188,000		732,184
China Pacific Insurance Group Co. Ltd., Class A		15,500		84,402
China Pacific Insurance Group Co. Ltd., Class H		128,800		507,474
China Petroleum & Chemical Corp., Class A		90,900		66,871
China Petroleum & Chemical Corp., Class H		1,228,400		739,657
China Power International Development Ltd.		483,000		103,528
China Railway Construction Corp. Ltd., Class A		81,100		118,228
China Railway Construction Corp. Ltd., Class H		67,000		73,379
China Railway Group Ltd., Class H		230,000		141,931
China Resources Beer Holdings Co. Ltd.		80,000		442,527
China Resources Cement Holdings Ltd.		122,000		155,303
China Resources Gas Group Ltd.		48,000		263,749
China Resources Land Ltd.		133,111		662,272
China Resources Pharmaceutical Group Ltd.(d)		69,500		64,430
China Resources Power Holdings Co. Ltd.		118,000		165,683
China Shenhua Energy Co. Ltd., Class A		31,800		83,446
China Shenhua Energy Co. Ltd., Class H		140,000		292,726
China Shipbuilding Industry Co. Ltd.		99,699		75,153
China Southern Airlines Co. Ltd., Class H		120,000		80,686
China State Construction Engineering Corp. Ltd., Class A		105,700		85,409
China State Construction International Holdings Ltd.		70,000		63,554
China Taiping Insurance Holdings Co. Ltd.		72,672		180,266
China Telecom Corp. Ltd., Class H		612,000		252,137
China Tower Corp. Ltd., Class H(d)		1,824,000		402,976
China Traditional Chinese Medicine Holdings Co. Ltd.		178,000		85,901
China Unicom Hong Kong Ltd.		288,000		271,187
China United Network Communications Ltd., Class A		118,200		100,159
China Vanke Co. Ltd., Class A		21,601		100,029
China Vanke Co. Ltd., Class H		83,000		354,086
China Yangtze Power Co. Ltd., Class A		90,600		239,426
Chongqing Rural Commercial Bank Co. Ltd., Class H		122,000		62,322
CIFI Holdings Group Co. Ltd.		170,000		143,741
CITIC Ltd.		220,000		293,638
CITIC Securities Co. Ltd., Class A		32,100		116,913

SCHEDULE OF INVESTMENTS 21

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
China (continued)
CITIC Securities Co. Ltd., Class H(a)		103,000	$	234,987
CNOOC Ltd.		862,000		1,433,359
Contemporary Amperex Technology Co. Ltd.		9,600		146,931
COSCO SHIPPING Energy Transportation Co. Ltd., Class H		180,000		85,017
COSCO SHIPPING Holdings Co. Ltd.(b)		201,698		152,948
COSCO SHIPPING Ports Ltd.		134,000		109,749
Country Garden Holdings Co. Ltd.		341,270		546,210
Country Garden Services Holdings Co. Ltd.(a)		67,000		225,577
CRRC Corp. Ltd., Class A		99,799		102,497
CRRC Corp. Ltd., Class H		222,350		162,104
CSPC Pharmaceutical Group Ltd.		220,000		525,007
Dali Foods Group Co. Ltd.(d)		175,500		130,020
Daqin Railway Co. Ltd., Class A		125,000		147,498
Dongfeng Motor Group Co. Ltd., Class H		138,000		129,828
East Money Information Co. Ltd.		4,500		10,217
ENN Energy Holdings Ltd.		43,100		470,876
Far East Horizon Ltd.		141,000		132,122
Focus Media Information Technology Co. Ltd., Class A		124,100		111,802
Foshan Haitian Flavouring & Food Co. Ltd., Class A		6,300		97,464
Fosun International Ltd.		131,500		191,816
Fuyao Glass Industry Group Co. Ltd., Class A		31,200		107,564
GD Power Development Co. Ltd., Class A		234,500		78,888
GDS Holdings Ltd. — ADR(a)(b)		2,591		133,644
Geely Automobile Holdings Ltd.		228,000		446,403
Genscript Biotech Corp.(b)		36,000		81,800
GF Securities Co. Ltd., Class H		93,600		114,003
GOME Retail Holdings Ltd.(a)(b)		627,000		57,973
Great Wall Motor Co. Ltd., Class H		157,500		116,535
Gree Electric Appliances, Inc. of Zhuhai, Class A(b)		11,300		106,633
Greenland Holdings Corp. Ltd., Class A		208,399		208,112
Greentown Service Group Co. Ltd.(a)		94,000		102,610
Guangdong Investment Ltd.		122,000		255,170
Guangzhou Automobile Group Co. Ltd., Class H(a)		134,400		167,327
Guangzhou R&F Properties Co. Ltd., Class H(a)		26,000		48,011
Guotai Junan Securities Co. Ltd., Class A		55,544		147,832
Haidilao International Holding Ltd.(d)		20,000		80,324
Haitian International Holdings Ltd.		67,000		162,280
Haitong Securities Co. Ltd., Class A		100,400		223,508
Haitong Securities Co. Ltd., Class H		163,200		192,795
Hangzhou Hikvision Digital Technology Co. Ltd., Class A		34,899		164,615
Hansoh Pharmaceutical Group Co. Ltd.(b)(d)		36,000		119,892
Hengan International Group Co. Ltd.		28,000		199,446
Hua Hong Semiconductor Ltd.(a)(d)		43,000		97,944
Huadian Power International Corp. Ltd., Class H		208,000		79,033
Huaneng Power International, Inc., Class H		192,000		97,086
Huaneng Renewables Corp. Ltd., Class H		158,000		61,440
Huatai Securities Co. Ltd., Class A		31,600		92,353
Huatai Securities Co. Ltd., Class H(d)		68,800		121,681
Huaxia Bank Co. Ltd., Class A		132,899		146,510
Huayu Automotive Systems Co. Ltd., Class A		37,100		138,633
Huazhu Group Ltd., ADR(a)		6,229		249,596
HUYA, Inc., ADR(b)		5,331		95,691
Iflytek Co. Ltd., Class A		35,000		173,744
Industrial & Commercial Bank of China Ltd., Class A		231,800		195,955
Industrial & Commercial Bank of China Ltd., Class H		3,143,000		2,424,914
Industrial Bank Co. Ltd., Class A		73,700		209,785
Inner Mongolia BaoTou Steel Union Co. Ltd., Class A		710,900		134,948
Inner Mongolia Yili Industrial Group Co. Ltd., Class A		19,400		86,361
Innovent Biologics, Inc.(b)(d)		41,500		141,647
iQIYI, Inc., ADR(a)(b)		6,171		130,270
JD.com, Inc. — ADR(b)		35,030		1,234,107
Jiangsu Expressway Co. Ltd., Class H		26,000		35,628
Jiangsu Hengrui Medicine Co. Ltd., Class A		14,800		186,308

Security	Shares		Value
China (continued)
Jiangsu Yanghe Brewery Joint-Stock Co. Ltd., Class A		5,200	$	82,703
Jiangxi Copper Co. Ltd., Class H		36,000		49,513
JOYY, Inc., ADR(a)(b)		2,186		115,399
Kaisa Group Holdings Ltd.(b)		221,000		105,500
Kingboard Holdings Ltd.		35,000		111,007
Kingdee International Software Group Co. Ltd.(a)		100,000		100,044
Kingsoft Corp. Ltd.(b)		25,000		64,835
Kunlun Energy Co. Ltd.		134,000		118,381
Kweichow Moutai Co. Ltd., Class A		3,716		632,765
KWG Group Holdings Ltd.(b)		74,000		103,680
Lenovo Group Ltd.(a)		322,000		216,240
Li Ning Co. Ltd.		98,500		295,429
Logan Property Holdings Co. Ltd.		72,000		120,810
Longfor Group Holdings Ltd.(d)		74,500		348,882
Luxshare Precision Industry Co. Ltd., Class A		24,100		126,742
Luye Pharma Group Ltd.(d)		111,000		83,220
Luzhou Laojiao Co. Ltd., Class A		11,300		140,955
Meituan Dianping, Class B(b)		50,200		655,920
Metallurgical Corp. of China Ltd., Class A		330,500		133,064
Midea Group Co. Ltd., Class A		17,300		145,136
Momo, Inc., ADR(a)		7,937		265,890
Muyuan Foodstuff Co. Ltd.		800		10,204
NARI Technology Co. Ltd., Class A		35,700		108,763
NetEase, Inc. — ADR(a)		3,531		1,082,746
New China Life Insurance Co. Ltd., Class H		43,200		185,721
New Oriental Education & Technology Group, Inc. — ADR(b)		6,612		801,705
Nexteer Automotive Group Ltd.(a)		81,000		73,418
NIO, Inc., ADR(a)(b)		23,275		93,566
Noah Holdings Ltd., ADR(a)(b)		1,707		60,377
People’s Insurance Co. Group of China Ltd., Class H		381,000		158,409
PetroChina Co. Ltd., Class H		818,000		411,777
PICC Property & Casualty Co. Ltd., Class H		320,298		386,061
Pinduoduo, Inc., ADR(b)		7,986		302,031
Ping An Bank Co. Ltd., Class A		47,100		111,510
Ping An Healthcare and Technology Co. Ltd.(b)(d)		16,800		122,618
Ping An Insurance Group Co. of China Ltd., Class A		35,100		431,608
Ping An Insurance Group Co. of China Ltd., Class H		269,000		3,183,201
Poly Developments and Holdings Group Co. Ltd., Class A		43,000		100,025
Postal Savings Bank of China Co. Ltd., Class H(d)		453,000		308,079
Prosus NV(b)		23,738		1,776,589
Qingdao Haier Co. Ltd., Class A		41,800		117,289
SAIC Motor Corp. Ltd., Class A		30,300		103,895
Sany Heavy Industry Co. Ltd., Class A		32,700		80,277
Seazen Group Ltd.(a)(b)		108,000		131,530
Semiconductor Manufacturing International Corp.(b)		187,600		287,389
Shaanxi Coal Industry Co. Ltd.		97,600		126,187
Shandong Gold Mining Co. Ltd.(b)		20,860		96,930
Shandong Weigao Group Medical Polymer Co. Ltd., Class H		132,000		158,169
Shanghai Electric Group Co. Ltd., Class H		104,000		34,174
Shanghai Fosun Pharmaceutical Group Co. Ltd., Class A		28,962		110,916
Shanghai Fosun Pharmaceutical Group Co. Ltd., Class H		21,500		64,886
Shanghai Industrial Holdings Ltd.(b)		15,000		28,876
Shanghai International Airport Co. Ltd., Class A		11,200		126,957
Shanghai Lujiazui Finance & Trade Zone Development Co. Ltd., Class B		60,800		58,760
Shanghai Pharmaceuticals Holding Co. Ltd., Class H		62,000		120,651
Shanghai Pudong Development Bank Co. Ltd., Class A		94,987		168,937
Shanxi Xinghuacun Fen Wine Factory Co. Ltd.		300		3,869
Shenwan Hongyuan Group Co. Ltd., Class A		127,900		94,208
Shenzhen Expressway Co., Ltd.		24,000		34,439
Shenzhen International Holdings Ltd.		40,500		88,975
Shenzhou International Group Holdings Ltd.		35,000		511,527
Shimao Property Holdings Ltd.		51,000		197,645
SINA Corp.(b)		2,721		108,650

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
China (continued)
Sino-Ocean Group Holding Ltd.		137,000	$	54,995
Sinopec Engineering Group Co. Ltd., Class H		105,500		63,145
Sinopec Shanghai Petrochemical Co. Ltd., Class H		123,000		37,131
Sinopharm Group Co. Ltd., Class H		48,000		175,147
Sinotruk Hong Kong Ltd.		56,000		119,520
SOHO China Ltd.		195,000		73,562
Sunac China Holdings Ltd.		109,000		650,733
Suning.com Co. Ltd., Class A		59,200		86,067
Sunny Optical Technology Group Co. Ltd.		35,700		618,542
TAL Education Group — ADR(b)		17,329		835,258
Tencent Holdings Ltd.		274,400		13,219,528
Tencent Music Entertainment Group, ADR(b)		5,966		70,041
Tingyi Cayman Islands Holding Corp.		88,000		150,193
TravelSky Technology Ltd.,Class H		59,000		144,031
Trip.com Group Ltd., ADR(b)		23,776		797,447
Tsingtao Brewery Co. Ltd., Class H		14,000		94,054
Uni-President China Holdings Ltd.		82,000		86,147
Vipshop Holdings Ltd. — ADR(b)		19,089		270,491
Wanhua Chemical Group Co. Ltd.		14,700		118,952
Want Want China Holdings Ltd.(a)		192,000		179,340
Weibo Corp. — ADR(a)(b)		2,003		92,839
Weichai Power Co. Ltd., Class H		96,800		204,318
Wens Foodstuffs Group Co. Ltd., Class A		16,800		81,138
Wuchan Zhongda Group Co. Ltd.		158,199		119,445
Wuliangye Yibin Co. Ltd., Class A		9,600		183,832
WuXi AppTec Co. Ltd., Class A		7,700		101,972
WuXi AppTec Co. Ltd., Class H(d)		11,020		136,629
Wuxi Biologics Cayman, Inc.(b)(d)		31,500		398,961
Xiaomi Corp., Class B(b)(d)		353,800		489,969
Xinjiang Goldwind Science & Technology Co. Ltd., Class H		69,600		80,879
Xinyi Solar Holdings Ltd.		164,000		116,525
Yangzijiang Shipbuilding Holdings Ltd.		94,000		78,355
Yanzhou Coal Mining Co. Ltd., Class H		108,000		97,032
Yihai International Holding Ltd.(b)		23,000		135,014
Yonghui Superstores Co. Ltd., Class A		104,798		113,613
Yonyou Network Technology Co. Ltd., Class A		6,000		24,543
Yum China Holdings, Inc.(a)		16,777		805,464
Yunnan Baiyao Group Co. Ltd., Class A		8,900		114,518
Zhangzhou Pientzehuang Pharmaceutical Co. Ltd., Class A		7,799		123,264
Zhaojin Mining Industry Co. Ltd., Class H		69,000		75,694
Zhejiang Chint Electrics Co. Ltd., Class A(b)		25,000		96,345
Zhejiang Expressway Co. Ltd., Class H		54,000		49,231
Zhenro Properties Group Ltd.(a)		57,000		40,959
ZhongAn Online P&C Insurance Co. Ltd., Class H(b)(d)		30,700		110,766
Zhongsheng Group Holdings Ltd.(a)		30,000		122,865
Zhuzhou CRRC Times Electric Co. Ltd., Class H		28,400		102,754
Zijin Mining Group Co. Ltd., Class H		218,000		108,274
ZTE Corp., Class H(b)		14,400		44,074
ZTO Express Cayman, Inc., — ADR(a)		16,995		396,833
				103,608,333
Colombia — 0.1%
Bancolombia SA		7,812		104,565
Ecopetrol SA		242,372		244,419
Grupo Argos SA		6,618		35,836
Grupo de Inversiones Suramericana SA		15,087		156,046
Interconexion Electrica SA		24,518		146,188
Millicom International Cellular SA, SDR		4,663		223,935
				910,989
Czech Republic — 0.0%
CEZ AS		9,764		219,442
Komercni Banka AS		3,800		139,162
Moneta Money Bank AS(d)		25,594		96,032
				454,636

Security	Shares		Value
Denmark — 1.2%
AP Moeller — Maersk A/S, Class B		257	$	370,656
AP Moeller — Maersk A/S, Class A		235		318,538
Carlsberg A/S, Class B		5,272		786,772
Chr Hansen Holding A/S		4,740		376,675
Coloplast A/S, Class B		4,915		609,760
Danske Bank A/S		33,364		539,773
Demant A/S(b)		6,575		207,065
DSV PANALPINA A/S		10,187		1,174,085
Genmab A/S(b)		3,029		673,660
H Lundbeck A/S		4,294		164,162
ISS A/S		6,402		153,615
Novo Nordisk A/S, Class B		84,730		4,910,005
Novozymes A/S, Class B		11,276		551,795
Orsted A/S(d)		9,561		988,844
Pandora A/S		4,563		198,497
Tryg A/S		7,189		213,128
Vestas Wind Systems A/S		8,948		903,805
				13,140,835
Egypt — 0.0%
Commercial International Bank Egypt SAE		50,357		260,476
Finland — 0.7%
Elisa OYJ		6,381		352,510
Fortum OYJ		21,500		530,694
Kone OYJ, Class B		15,943		1,042,478
Metso OYJ		5,754		227,312
Neste OYJ		20,322		707,107
Nokia OYJ(b)		261,220		966,218
Nokian Renkaat OYJ		5,359		154,135
Nordea Bank Abp		158,649		1,283,499
Orion OYJ, Class B		5,835		270,228
Sampo OYJ, Class A		21,362		932,731
Stora Enso OYJ, Class R		24,213		352,318
UPM-Kymmene OYJ		26,197		908,892
Wartsila OYJ Abp		20,628		228,011
				7,956,133
France — 7.2%
Accor SA		9,457		443,900
Aeroports de Paris		1,364		270,063
Air Liquide SA		22,521		3,192,819
Airbus SE		28,080		4,121,165
Alstom SA		8,422		400,205
Amundi SA(d)		3,754		295,201
Arkema SA		2,951		315,543
Atos SE		4,016		335,589
AXA SA		92,922		2,625,626
BioMerieux		1,981		176,614
BNP Paribas SA		53,628		3,187,545
Bollore SA		36,855		161,053
Bouygues SA		11,423		486,928
Bureau Veritas SA		10,607		277,287
Capgemini SE		7,745		947,251
Carrefour SA		28,356		476,910
Casino Guichard-Perrachon SA(b)		2,868		134,150
Cie de Saint-Gobain		23,735		972,324
Cie Generale des Etablissements Michelin SCA		8,630		1,062,000
CNP Assurances		7,565		150,734
Covivio		2,326		264,163
Credit Agricole SA		52,326		761,413
Danone SA		29,226		2,427,100
Dassault Aviation SA		127		166,673
Dassault Systemes SE		6,378		1,051,894
Edenred		11,567		599,453
Eiffage SA		3,691		423,457

SCHEDULE OF INVESTMENTS 23

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
France (continued)
Electricite de France SA		30,963	$	345,494
Engie SA		84,000		1,360,659
EssilorLuxottica SA		13,760		2,103,649
Eurazeo SE		2,062		141,538
Eutelsat Communications SA		6,653		108,134
Faurecia SE		3,630		197,064
Gecina SA		2,235		400,117
Getlink SE		23,156		403,722
Hermes International		1,529		1,145,386
ICADE		1,426		155,273
Iliad SA		961		124,999
Ingenico Group SA		2,934		319,155
Ipsen SA		1,966		174,515
JCDecaux SA		5,899		182,267
Kering SA		3,651		2,405,697
Klepierre SA		10,451		397,597
L’Oreal SA		11,973		3,540,505
Legrand SA		12,821		1,047,011
LVMH Moet Hennessy Louis Vuitton SE		13,284		6,189,728
Natixis SA		41,329		184,101
Orange SA		94,138		1,383,471
Pernod Ricard SA		10,131		1,812,816
Peugeot SA		27,622		665,059
Publicis Groupe SA		10,028		454,684
Remy Cointreau SA		958		117,667
Renault SA		9,369		444,910
Safran SA		15,657		2,418,369
Sanofi		53,719		5,394,861
Sartorius Stedim Biotech		1,419		235,536
Schneider Electric SE		26,164		2,688,082
SCOR SE		8,239		346,827
SEB SA		1,060		157,651
Societe Generale SA		38,898		1,357,461
Sodexo SA		4,102		486,118
Suez		20,135		305,111
Teleperformance		2,820		688,976
Thales SA		5,674		590,407
TOTAL SA		113,358		6,290,293
UbiSoft Entertainment SA(b)		3,326		230,436
Unibail-Rodamco-Westfield		6,636		1,046,943
Valeo SA		12,421		440,241
Veolia Environnement SA		24,151		642,618
Vinci SA		24,177		2,692,679
Vivendi SA		44,181		1,279,372
Wendel SA		1,358		180,896
Worldline SA(b)(d)		4,359		309,014
				79,314,169
Germany — 5.3%
adidas AG		8,655		2,813,469
Allianz SE, Registered Shares		20,159		4,939,515
Aroundtown SA		42,024		377,450
BASF SE		44,016		3,316,017
Bayer AG, Registered Shares		44,803		3,642,331
Bayerische Motoren Werke AG		15,516		1,270,849
Beiersdorf AG		4,329		517,875
Brenntag AG		6,771		367,372
Carl Zeiss Meditec AG, Bearer Shares		2,236		284,262
Commerzbank AG		42,982		265,458
Continental AG		5,218		674,323
Covestro AG(d)		8,522		396,529
Daimler AG, Registered Shares		42,097		2,327,303
Delivery Hero SE(b)(d)		5,971		473,257
Deutsche Bank AG, Registered Shares		97,089		752,296
Deutsche Boerse AG		9,113		1,429,033

Security	Shares		Value
Germany (continued)
Deutsche Lufthansa AG, Registered Shares		9,239	$	170,063
Deutsche Post AG, Registered Shares		47,617		1,810,596
Deutsche Telekom AG, Registered Shares		157,635		2,576,098
Deutsche Wohnen SE, Bearer Shares		17,911		728,562
E.ON SE		108,066		1,154,888
Evonik Industries AG		10,596		323,626
Fraport AG Frankfurt Airport Services Worldwide		2,602		220,871
Fresenius Medical Care AG & Co. KGaA		10,055		740,328
Fresenius SE & Co. KGaA		19,365		1,089,735
GEA Group AG		8,213		271,585
Hannover Rueck SE		2,781		536,217
HeidelbergCement AG		6,401		465,128
Henkel AG & Co. KGaA		5,345		502,390
Hochtief AG		1,191		151,633
Infineon Technologies AG		58,082		1,312,325
KION Group AG		3,141		215,998
Knorr-Bremse AG		2,374		241,660
LANXESS AG		3,663		245,946
Merck KGaA		6,299		742,613
METRO AG		12,460		200,496
MTU Aero Engines AG		2,395		682,397
Muenchener Rueckversicherungs-Gesellschaft AG, Registered Shares		6,784		2,001,910
Puma SE		4,318		331,113
RWE AG		29,409		901,149
SAP SE		47,150		6,346,302
Siemens AG, Registered Shares		36,653		4,786,572
Siemens Healthineers AG(d)		6,578		315,330
Symrise AG		6,068		637,801
Telefonica Deutschland Holding AG		31,438		91,122
Thyssenkrupp AG(a)(b)		21,457		288,320
TUI AG		20,400		257,453
Uniper SE		9,623		318,056
United Internet AG, Registered Shares		7,997		261,896
Volkswagen AG		1,862		360,641
Vonovia SE		24,821		1,333,120
Wirecard AG		5,813		700,947
Zalando SE(b)(d)		7,207		363,450
				57,525,676
Greece — 0.1%
Alpha Bank AE(b)		69,105		149,279
Eurobank Ergasias SA(b)		107,023		110,673
FF Group(b)(e)		205		2
Hellenic Telecommunications Organization SA		12,770		204,405
JUMBO SA		4,656		96,880
Motor Oil Hellas Corinth Refineries SA		3,560		82,396
National Bank of Greece SA(b)		32,926		111,776
OPAP SA		10,676		138,900
				894,311
Hong Kong — 2.0%
AIA Group Ltd.		580,800		6,108,831
Alibaba Pictures Group Ltd.(a)(b)		480,000		84,401
ASM Pacific Technology Ltd.		12,700		176,281
Bank of East Asia Ltd.(a)		59,000		131,725
Bosideng International Holdings Ltd.		258,000		93,073
China Common Rich Renewable Energy Investments Ltd.(b)(e)		11,997		—
China Ding Yi Feng Holdings Ltd.(e)		40,000		411
China First Capital Group Ltd.(b)		148,000		5,128
CK Asset Holdings Ltd.		121,008		873,221
CK Infrastructure Holdings Ltd.		26,000		185,034
CLP Holdings Ltd.		81,500		855,539
Dairy Farm International Holdings Ltd.		13,100		74,801

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Hong Kong (continued)
Haier Electronics Group Co. Ltd.		48,000	$	149,968
Hang Lung Properties Ltd.		70,000		153,702
Hang Seng Bank Ltd.		35,000		723,449
Henderson Land Development Co. Ltd.		66,800		327,791
HK Electric Investments & HK Electric Investments Ltd.(c)		204,000		201,060
HKT Trust & HKT Ltd.(c)		185,900		261,986
Hong Kong & China Gas Co. Ltd.		478,619		935,159
Hong Kong Exchanges & Clearing Ltd.		57,300		1,861,547
Hongkong Land Holdings Ltd.		72,900		419,325
Hutchison China MediTech, Ltd., ADR(a)(b)		3,003		75,285
Jardine Matheson Holdings Ltd.		10,400		578,736
Jardine Strategic Holdings Ltd.(a)		12,400		380,284
Kerry Properties Ltd.		27,500		87,342
Kingboard Laminates Holdings Ltd.		42,500		52,681
Link REIT		98,000		1,038,209
Melco Resorts & Entertainment Ltd. — ADR		11,155		269,616
MTR Corp. Ltd.		83,500		493,444
New World Development Co. Ltd.		280,666		384,721
Nine Dragons Paper Holdings Ltd.		39,000		40,557
NWS Holdings Ltd.		52,186		73,142
PCCW Ltd.		135,000		79,879
Power Assets Holdings Ltd.		71,500		523,067
Sino Biopharmaceutical Ltd.		371,500		519,735
Sino Land Co. Ltd.		130,800		189,857
SSY Group Ltd.		104,000		84,238
Sun Art Retail Group Ltd.		110,000		133,474
Sun Hung Kai Properties Ltd.		74,500		1,140,958
Swire Pacific Ltd., Class A		21,000		195,084
Swire Properties Ltd.		71,600		237,200
Techtronic Industries Co. Ltd.		72,000		587,642
Vitasoy International Holdings Ltd.(a)		30,000		108,828
WH Group Ltd.(d)		460,000		475,628
Wharf Holdings Ltd.		61,000		155,043
Wharf Real Estate Investment Co. Ltd.		48,000		292,875
Wheelock & Co. Ltd.		34,000		226,654
Yue Yuen Industrial Holdings Ltd.		28,000		82,636
				22,129,247
Hungary — 0.1%
MOL Hungarian Oil & Gas PLC		16,294		162,420
OTP Bank Nyrt		11,103		581,353
Richter Gedeon Nyrt		3,096		67,312
				811,085
India — 2.4%
Adani Ports & Special Economic Zone Ltd.		27,638		141,773
Ambuja Cements Ltd.		26,422		72,660
Ashok Leyland Ltd.		63,339		72,404
Asian Paints Ltd.		12,475		312,029
Aurobindo Pharma Ltd.		13,516		86,508
Avenue Supermarts, Ltd.(b)(d)		5,577		143,719
Axis Bank Ltd.		93,214		985,355
Bajaj Auto Ltd.		3,300		147,305
Bajaj Finance Ltd.		7,651		454,146
Bajaj Finserv Ltd.		1,518		199,860
Bandhan Bank Ltd.(d)		15,438		109,969
Berger Paints India Ltd.		8,379		60,520
Bharat Forge Ltd.		11,954		80,960
Bharat Petroleum Corp. Ltd.		35,066		241,199
Bharti Airtel Ltd.(b)		103,040		657,983
Bharti Infratel Ltd.		35,488		125,539
Bosch Ltd.		292		62,913
Britannia Industries, Ltd.		2,511		106,555
Cipla Ltd.		13,384		89,681
Coal India Ltd.		75,173		222,866

Security	Shares		Value
India (continued)
Colgate-Palmolive India Ltd.		5,077	$	104,093
Container Corp. Of India Ltd.		7,502		60,108
Dabur India Ltd.		20,426		131,233
Divi’s Laboratories Ltd.		3,485		90,185
DLF Ltd.		33,599		108,709
Dr. Reddy’s Laboratories Ltd.		1,007		40,587
Dr. Reddy’s Laboratories Ltd. — ADR(a)		4,517		183,300
Eicher Motors Ltd.		644		203,373
GAIL India Ltd.		43,712		74,097
Godrej Consumer Products Ltd.		13,857		132,934
Grasim Industries Ltd.		15,713		163,731
Havells India Ltd.		8,781		79,613
HCL Technologies Ltd.		46,092		366,847
HDFC Asset Management Co. Ltd.(d)		2,674		119,899
HDFC Standard Life Insurance Co. Ltd.(d)		20,635		181,061
Hero MotoCorp Ltd.		4,266		146,048
Hindalco Industries Ltd.		75,665		229,388
Hindustan Petroleum Corp. Ltd.		16,963		62,743
Hindustan Unilever Ltd.		31,045		836,632
Housing Development Finance Corp. Ltd.		79,040		2,672,535
ICICI Bank Ltd.		191,508		1,452,351
ICICI Bank Ltd. — ADR(a)		22,806		344,142
ICICI Lombard General Insurance Co. Ltd.(d)		5,224		101,497
ICICI Prudential Life Insurance Co. Ltd.(d)		12,623		85,320
Indian Oil Corp. Ltd.		94,789		166,568
Info Edge India Ltd.		4,063		144,016
Infosys Ltd.		64,313		662,297
Infosys Ltd. — ADR(a)		97,713		1,008,398
InterGlobe Aviation Ltd.(d)		5,982		111,761
ITC Ltd.		167,563		558,124
JSW Steel Ltd.		32,800		124,265
Larsen & Toubro Ltd.		5,195		94,500
Larsen & Toubro Ltd. — GDR		18,237		335,057
LIC Housing Finance Ltd.		17,978		109,392
Lupin Ltd.		11,830		126,613
Mahindra & Mahindra Financial Services Ltd.		10,804		48,834
Mahindra & Mahindra Ltd.		3,897		29,039
Mahindra & Mahindra Ltd., — GDR		27,036		204,392
Marico Ltd.		22,064		105,616
Maruti Suzuki India Ltd.		4,353		449,453
Motherson Sumi Systems Ltd.		67,315		138,337
Nestle India Ltd.		1,381		286,062
NTPC Ltd.		151,656		252,944
Oil & Natural Gas Corp. Ltd.		142,049		256,505
Page Industries Ltd.		266		87,214
Petronet LNG Ltd.		23,885		89,693
Pidilite Industries Ltd.		5,574		108,305
Piramal Enterprises Ltd.		4,721		100,870
Power Grid Corp. of India Ltd.		92,096		245,471
REC Ltd.		38,827		77,864
Reliance Industries Ltd.		23,507		498,633
Reliance Industries Ltd., — GDR(d)		54,998		2,340,165
SBI Life Insurance Co. Ltd.(d)		13,281		179,005
Shree Cement Ltd.		615		175,467
Shriram Transport Finance Co. Ltd.		5,718		93,815
Siemens Ltd.		4,979		104,442
State Bank of India(b)		27,343		127,958
State Bank of India — GDR(b)		5,712		267,322
Sun Pharmaceutical Industries Ltd.		43,350		262,700
Tata Consultancy Services Ltd.		43,804		1,326,612
Tata Motors Ltd.(b)		52,939		137,108
Tata Motors Ltd. — ADR(b)		6,008		77,683
Tata Power Co. Ltd.		42,988		34,039
Tata Steel Ltd.		11,672		77,316

SCHEDULE OF INVESTMENTS 25

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
India (continued)
Tech Mahindra Ltd.		26,191	$	279,713
Titan Co. Ltd.		17,951		298,908
UltraTech Cement Ltd.		4,530		256,872
United Spirits Ltd.(b)		18,510		155,532
UPL Ltd.		26,481		216,816
Vedanta Ltd.		28,074		60,050
Vedanta Ltd. — ADR(a)		11,497		99,219
Wipro Ltd.		54,155		186,475
Wipro Ltd. — ADR		13,184		49,440
Zee Entertainment Enterprises Ltd.		50,406		206,346
				25,777,596
Indonesia — 0.5%
Ace Hardware Indonesia Tbk PT		253,400		27,289
Adaro Energy Tbk PT		1,086,700		121,440
Astra International Tbk PT		965,400		480,859
Bank Central Asia Tbk PT		459,900		1,106,062
Bank Mandiri Persero Tbk PT		892,400		493,108
Bank Negara Indonesia Persero Tbk PT		405,600		228,968
Bank Rakyat Indonesia Persero Tbk PT		2,771,400		877,220
Bank Tabungan Negara Persero Tbk PT		473,000		72,110
Barito Pacific Tbk PT		810,100		88,017
Bumi Serpong Damai Tbk PT(b)		384,500		34,653
Charoen Pokphand Indonesia Tbk PT		509,500		238,280
Gudang Garam Tbk PT		22,300		85,067
Hanjaya Mandala Sampoerna Tbk PT		483,800		73,074
Indah Kiat Pulp & Paper Corp. Tbk PT		126,800		70,176
Indocement Tunggal Prakarsa Tbk PT		88,600		121,181
Indofood CBP Sukses Makmur Tbk PT		162,400		130,411
Indofood Sukses Makmur Tbk PT		159,200		90,773
Jasa Marga Persero Tbk PT		75,780		28,211
Kalbe Farma Tbk PT		858,400		100,082
Pabrik Kertas Tjiwi Kimia Tbk PT		78,500		58,016
Pakuwon Jati Tbk PT		2,069,500		84,710
Perusahaan Gas Negara Persero Tbk PT		426,200		66,453
Semen Indonesia Persero Tbk PT		106,000		91,408
Telekomunikasi Indonesia Persero Tbk PT		2,223,800		637,068
Unilever Indonesia Tbk PT		74,900		226,417
United Tractors Tbk PT		79,900		123,709
XL Axiata Tbk PT(b)		131,400		29,787
				5,784,549
Ireland — 0.4%
AerCap Holdings NV(b)		6,636		407,915
AIB Group PLC		53,001		184,656
Bank of Ireland Group PLC		48,092		264,679
CRH PLC(b)		36,231		1,453,186
Flutter Entertainment PLC		3,768		457,948
Kerry Group PLC, Class A		7,704		960,079
Kingspan Group PLC		7,024		429,002
Smurfit Kappa Group PLC		9,784		377,243
				4,534,708
Israel — 0.4%
Azrieli Group Ltd.		2,198		161,008
Bank Hapoalim BM		59,725		496,003
Bank LeumiLe-Israel BM		69,019		503,351
Check Point Software Technologies Ltd.(b)		5,145		570,889
Elbit Systems Ltd.		1,599		249,146
Israel Chemicals Ltd.		34,017		160,646
Israel Discount Bank Ltd., Series A		49,699		230,813
Mizrahi Tefahot Bank Ltd.		7,034		187,628
Nice Ltd.(b)		3,246		503,322
Teva Pharmaceutical Industries Ltd. — ADR(b)		56,515		553,847
Wix.com Ltd.(b)		2,550		312,069
				3,928,722

Security	Shares		Value
Italy — 1.3%
Assicurazioni Generali SpA		53,781	$	1,110,298
Atlantia SpA		22,697		529,723
Davide Campari-Milano SpA		25,177		230,050
Enel SpA		387,286		3,076,531
Eni SpA		115,988		1,801,436
Ferrari NV		6,282		1,043,036
FinecoBank Banca Fineco SpA		23,619		283,329
Intesa Sanpaolo SpA		720,632		1,898,280
Leonardo SpA		15,326		179,733
Mediobanca Banca di Credito Finanziario SpA		34,909		384,367
Moncler SpA		8,703		391,700
Pirelli & C SpA(d)		15,564		89,830
Poste Italiane SpA(d)		21,934		249,233
Prysmian SpA		11,451		276,418
Recordati SpA		5,232		220,553
Snam SpA		78,577		413,142
Telecom Italia SpA(b)		415,147		259,263
Telecom Italia SpA		341,957		209,420
Terna Rete Elettrica Nazionale SpA		63,450		424,348
UniCredit SpA		99,720		1,457,603
				14,528,293
Japan — 15.8%
ABC-Mart, Inc.		1,700		116,044
Acom Co. Ltd.		14,700		66,696
Advantest Corp.		9,900		558,341
Aeon Co. Ltd.		31,100		641,792
AEON Financial Service Co. Ltd.		4,000		63,026
Aeon Mall Co. Ltd.		5,190		92,058
AGC, Inc.		10,200		364,731
Air Water, Inc.		10,700		156,130
Aisin Seiki Co. Ltd.		7,000		259,278
Ajinomoto Co., Inc.		22,200		369,570
Alfresa Holdings Corp.		8,900		180,804
Alps Alpine Co. Ltd.		7,600		172,515
Amada Holdings Co. Ltd.		13,600		154,683
ANA Holdings, Inc.		6,300		210,316
Aozora Bank Ltd.		4,500		118,884
Asahi Group Holdings Ltd.		17,700		807,483
Asahi Intecc Co. Ltd.		10,800		316,237
Asahi Kasei Corp.		63,200		709,635
Astellas Pharma, Inc.		92,300		1,575,559
Bandai Namco Holdings, Inc.		9,500		577,906
Bank of Kyoto Ltd.		3,000		127,923
Benesse Holdings, Inc.		4,800		126,167
Bridgestone Corp.		27,900		1,036,488
Brother Industries Ltd.		9,200		190,010
Calbee, Inc.		4,500		146,616
Canon, Inc.(a)		50,200		1,373,897
Casio Computer Co. Ltd.		7,800		155,871
Central Japan Railway Co.		6,500		1,306,947
Chiba Bank Ltd. (The)		26,100		150,073
Chubu Electric Power Co., Inc.		31,400		443,866
Chugai Pharmaceutical Co. Ltd.		11,100		1,022,257
Chugoku Electric Power Co., Inc.		14,700		193,233
Coca-Cola Bottlers Japan Holdings, Inc.		7,100		181,407
Concordia Financial Group Ltd.		48,900		200,817
Credit Saison Co. Ltd.		7,700		133,547
CyberAgent, Inc.		5,400		188,113
Dai Nippon Printing Co. Ltd.		13,300		359,732
Dai-ichi Life Holdings, Inc.		53,700		884,991
Daicel Corp.		11,900		113,768
Daifuku Co. Ltd.		4,900		296,131
Daiichi Sankyo Co. Ltd.		28,100		1,855,843
Daikin Industries Ltd.		11,300		1,594,314

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Japan (continued)
Daito Trust Construction Co. Ltd.		3,400	$	420,159
Daiwa House Industry Co. Ltd.		26,600		823,452
Daiwa House REIT Investment Corp.		85		222,261
Daiwa Securities Group, Inc.		65,000		328,147
Denso Corp.		21,200		957,441
Dentsu, Inc.		9,500		327,330
Disco Corp.		1,400		328,755
East Japan Railway Co.		14,800		1,335,876
Eisai Co. Ltd.		12,200		912,877
Electric Power Development Co. Ltd.		7,100		172,335
FamilyMart Co. Ltd.		14,600		349,666
FANUC Corp.		9,300		1,717,383
Fast Retailing Co. Ltd.		2,700		1,603,999
Fuji Electric Co. Ltd.		7,900		239,981
FUJIFILM Holdings Corp.		17,500		835,728
Fujitsu Ltd.		8,800		827,691
Fukuoka Financial Group, Inc.		7,600		145,206
GMO Payment Gateway, Inc.		1,500		102,722
Hakuhodo DY Holdings, Inc.		14,000		225,274
Hamamatsu Photonics KK		6,400		262,275
Hankyu Hanshin Holdings, Inc.		11,600		496,197
Hikari Tsushin, Inc.		1,000		251,298
Hino Motors Ltd.		12,500		132,194
Hirose Electric Co. Ltd.		1,611		205,937
Hisamitsu Pharmaceutical Co., Inc.		2,900		141,234
Hitachi Chemical Co. Ltd.		5,500		230,427
Hitachi Construction Machinery Co. Ltd.		4,600		137,022
Hitachi High-Technologies Corp.		4,000		283,278
Hitachi Ltd.		47,100		1,987,419
Hitachi Metals Ltd.		8,000		117,758
Honda Motor Co. Ltd.		77,000		2,179,218
Hoshizaki Corp.		2,500		222,900
Hoya Corp.		18,200		1,737,408
Hulic Co. Ltd.		20,500		246,824
Idemitsu Kosan Co. Ltd.		8,649		238,987
IHI Corp.		7,700		180,188
Iida Group Holdings Co. Ltd.		6,800		119,174
Inpex Corp.		45,900		475,511
Isetan Mitsukoshi Holdings Ltd.		11,500		103,267
Isuzu Motors Ltd.		24,900		294,337
ITOCHU Corp.		64,300		1,490,260
Itochu Techno-Solutions Corp.		7,100		199,951
J. Front Retailing Co. Ltd.		11,100		154,815
Japan Airlines Co. Ltd.		5,500		171,247
Japan Airport Terminal Co. Ltd.		1,700		94,325
Japan Exchange Group, Inc.		24,200		426,043
Japan Post Bank Co. Ltd.		18,900		181,342
Japan Post Holdings Co. Ltd.		78,500		738,250
Japan Post Insurance Co. Ltd.		10,400		177,284
Japan Prime Realty Investment Corp.		44		193,463
Japan Real Estate Investment Corp.		74		491,100
Japan Retail Fund Investment Corp.		107		230,254
Japan Tobacco, Inc.		58,600		1,306,578
JFE Holdings, Inc.		20,100		257,912
JGC Holdings Corp.		10,000		159,160
JSR Corp.		7,600		139,024
JTEKT Corp.		6,200		73,241
JXTG Holdings, Inc.		162,500		737,519
Kajima Corp.		21,700		288,505
Kakaku.com, Inc.		7,400		188,945
Kamigumi Co. Ltd.		4,300		94,522
Kansai Electric Power Co., Inc.		30,300		351,019
Kansai Paint Co. Ltd.		7,600		185,661
Kao Corp.		23,500		1,938,164

Security	Shares		Value
Japan (continued)
Kawasaki Heavy Industries Ltd.		5,800	$	126,769
KDDI Corp.		84,600		2,524,155
Keihan Holdings Co. Ltd.		4,600		223,360
Keikyu Corp.		11,000		212,069
Keio Corp.		5,500		332,801
Keisei Electric Railway Co. Ltd.		5,400		209,247
Keyence Corp.		8,680		3,047,881
Kikkoman Corp.		6,100		298,624
Kintetsu Group Holdings Co. Ltd.		9,000		488,158
Kirin Holdings Co. Ltd.		40,600		886,159
Kobayashi Pharmaceutical Co. Ltd.		2,600		220,223
Koito Manufacturing Co. Ltd.		4,500		208,377
Komatsu Ltd.		45,000		1,080,065
Konami Holdings Corp.		5,300		217,790
Konica Minolta, Inc.		25,700		167,412
Kose Corp.		1,700		247,799
Kubota Corp.		49,500		777,310
Kuraray Co. Ltd.		13,400		162,379
Kurita Water Industries Ltd.		7,400		219,595
Kyocera Corp.		15,300		1,042,782
Kyowa Kirin Co. Ltd.		12,600		296,860
Kyushu Electric Power Co., Inc.		14,400		124,934
Kyushu Railway Co.		6,700		224,300
Lawson, Inc.		1,900		107,849
LINE Corp.(b)		3,000		147,397
Lion Corp.		11,900		231,320
LIXIL Group Corp.		13,600		234,693
M3, Inc.		20,300		612,159
Makita Corp.		12,600		435,139
Marubeni Corp.		68,200		503,887
Marui Group Co. Ltd.		9,500		231,634
Maruichi Steel Tube Ltd.		2,400		67,446
Mazda Motor Corp.		30,300		258,199
McDonald’s Holdings Co. Japan Ltd.(a)		2,300		110,811
Mebuki Financial Group, Inc.		38,630		98,489
Medipal Holdings Corp.		10,300		227,325
MEIJI Holdings Co. Ltd.		4,900		331,143
Mercari, Inc.(b)		3,200		65,421
MINEBEA MITSUMI, Inc.		14,000		289,186
MISUMI Group, Inc.		15,500		383,627
Mitsubishi Chemical Holdings Corp.		59,500		443,345
Mitsubishi Corp.		65,700		1,740,482
Mitsubishi Electric Corp.		90,500		1,232,219
Mitsubishi Estate Co. Ltd.		54,700		1,046,677
Mitsubishi Gas Chemical Co., Inc.		9,300		141,678
Mitsubishi Heavy Industries Ltd.		14,800		573,897
Mitsubishi Materials Corp.		6,200		168,266
Mitsubishi Motors Corp.		36,300		151,308
Mitsubishi Tanabe Pharma Corp.		11,500		210,968
Mitsubishi UFJ Financial Group, Inc.		595,200		3,217,850
Mitsubishi UFJ Lease & Finance Co. Ltd.		15,200		97,853
Mitsui & Co. Ltd.		80,400		1,429,152
Mitsui Chemicals, Inc.		7,900		192,438
Mitsui Fudosan Co. Ltd.		40,900		999,593
Mitsui OSK Lines Ltd.		4,700		129,252
Mizuho Financial Group, Inc.		1,160,200		1,787,194
MonotaRO Co Ltd.		7,500		199,657
MS&AD Insurance Group Holdings, Inc.		23,700		782,305
Murata Manufacturing Co. Ltd.		27,000		1,661,811
Nabtesco Corp.		5,000		147,335
Nagoya Railroad Co. Ltd.		11,100		344,688
NEC Corp.		11,200		463,506
Nexon Co. Ltd.(b)		21,700		287,857
NGK Insulators Ltd.		9,000		156,564

SCHEDULE OF INVESTMENTS 27

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Japan (continued)
NGK Spark Plug Co. Ltd.		8,500	$	164,764
NH Foods Ltd.		4,000		165,694
Nidec Corp.		10,800		1,475,104
Nikon Corp.		14,700		179,776
Nintendo Co. Ltd.		5,400		2,159,784
Nippon Building Fund, Inc.		62		454,475
Nippon Express Co. Ltd.		3,800		222,752
Nippon Paint Holdings Co. Ltd.		7,500		386,112
Nippon Shinyaku Co. Ltd.		1,900		164,528
Nippon Steel Corp.		39,647		597,596
Nippon Telegraph & Telephone Corp.		61,600		1,556,859
Nippon Yusen KK		5,300		95,525
Nissan Chemical Corp.		5,900		247,079
Nissan Motor Co. Ltd.		120,400		697,686
Nisshin Seifun Group, Inc.		9,000		157,027
Nissin Foods Holdings Co. Ltd.		3,500		259,955
Nitori Holdings Co. Ltd.		4,100		647,190
Nitto Denko Corp.		7,300		410,463
Nomura Holdings, Inc.		162,300		835,161
Nomura Real Estate Holdings, Inc.		5,200		124,723
Nomura Real Estate Master Fund, Inc.		232		396,843
Nomura Research Institute Ltd.		14,343		306,740
NSK Ltd.		14,400		136,126
NTT Data Corp.		33,000		441,341
NTT DOCOMO, Inc.		61,900		1,724,294
Obayashi Corp.		34,800		386,512
Obic Co. Ltd.		2,800		377,162
Odakyu Electric Railway Co. Ltd.		16,400		382,596
Oji Holdings Corp.		39,000		210,911
Olympus Corp.		54,900		846,157
Omron Corp.		9,100		530,422
Ono Pharmaceutical Co. Ltd.		20,400		465,738
Oracle Corp. Japan		2,500		226,897
Oriental Land Co. Ltd.		9,600		1,309,837
ORIX Corp.		60,800		1,007,539
OrixJ-REIT, Inc.		142		307,791
Osaka Gas Co. Ltd.		18,700		357,603
Otsuka Corp.		5,800		231,623
Otsuka Holdings Co. Ltd.		18,100		806,794
Pan Pacific International Holdings Corp.		20,000		331,826
Panasonic Corp.		112,600		1,056,096
Park24 Co. Ltd.		6,400		156,711
PeptiDream, Inc.(b)		3,600		183,972
Persol Holdings Co. Ltd.		8,300		155,551
Pigeon Corp.		7,100		259,975
Pola Orbis Holdings, Inc.		5,600		133,387
Rakuten, Inc.		39,300		335,747
Recruit Holdings Co. Ltd.		65,200		2,442,087
Renesas Electronics Corp.(b)		36,900		252,099
Resona Holdings, Inc.		94,700		412,753
Ricoh Co. Ltd.		28,600		311,211
Rinnai Corp.		2,100		164,113
Rohm Co. Ltd.		3,800		303,198
Ryohin Keikaku Co. Ltd.		11,000		256,370
Sankyo Co. Ltd.		2,200		73,068
Santen Pharmaceutical Co. Ltd.		19,900		378,959
SBI Holdings, Inc.		12,550		264,959
Secom Co. Ltd.		9,600		856,730
Sega Sammy Holdings, Inc.		8,800		127,421
Seibu Holdings, Inc.		9,800		161,207
Seiko Epson Corp.		14,900		224,973
Sekisui Chemical Co. Ltd.		14,400		249,839
Sekisui House Ltd.		29,600		632,103
Seven & i Holdings Co. Ltd.		37,200		1,363,581

Security	Shares		Value
Japan (continued)
Seven Bank Ltd.		32,800	$	107,456
SG Holdings Co. Ltd.		6,400		144,165
Sharp Corp.		14,100		215,483
Shimadzu Corp.		11,000		344,005
Shimamura Co. Ltd.(a)		1,100		83,626
Shimano, Inc.		3,300		535,362
Shimizu Corp.		19,400		197,624
Shin-Etsu Chemical Co. Ltd.		17,500		1,924,528
Shinsei Bank Ltd.		10,800		164,778
Shionogi & Co. Ltd.		12,300		760,896
Shiseido Co. Ltd.		19,200		1,363,391
Shizuoka Bank Ltd.		16,000		119,012
Showa Denko KK		8,400		221,386
SMC Corp.		2,800		1,280,483
Softbank Corp.		82,300		1,103,616
SoftBank Group Corp.		76,400		3,317,060
Sohgo Security Services Co. Ltd.		4,200		227,325
Sompo Holdings, Inc.		14,800		581,190
Sony Corp.		61,100		4,148,547
Sony Financial Holdings, Inc.		6,900		165,634
Square Enix Holdings Co. Ltd.		4,200		209,134
Stanley Electric Co. Ltd.		5,700		164,623
Subaru Corp.		29,800		738,141
Sumco Corp.		9,700		160,717
Sumitomo Chemical Co. Ltd.		54,400		247,007
Sumitomo Corp.		53,300		791,683
Sumitomo Dainippon Pharma Co. Ltd.		6,600		127,876
Sumitomo Electric Industries Ltd.		33,500		503,108
Sumitomo Heavy Industries Ltd.		4,400		124,981
Sumitomo Metal Mining Co. Ltd.		10,100		325,220
Sumitomo Mitsui Financial Group, Inc.		61,900		2,286,298
Sumitomo Mitsui Trust Holdings, Inc.		15,200		600,870
Sumitomo Realty & Development Co. Ltd.		16,000		558,232
Sumitomo Rubber Industries Ltd.		5,200		63,407
Sundrug Co. Ltd.		4,000		144,728
Suntory Beverage & Food Ltd.		6,300		263,017
Suzuken Co. Ltd.		3,170		129,202
Suzuki Motor Corp.		18,800		784,748
Sysmex Corp.		9,000		612,764
T&D Holdings, Inc.		24,800		313,613
Taiheiyo Cement Corp.		5,900		173,183
Taisei Corp.		8,800		364,505
Taisho Pharmaceutical Holdings Co. Ltd.		1,300		95,934
Taiyo Nippon Sanso Corp.		9,300		205,846
Takeda Pharmaceutical Co. Ltd.		71,676		2,834,943
TDK Corp.		5,600		629,323
Teijin Ltd.		7,200		134,511
Terumo Corp.		29,500		1,046,492
THK Co. Ltd.		5,800		155,720
Tobu Railway Co. Ltd.		8,100		293,228
Toho Co. Ltd.		5,500		229,197
Toho Gas Co. Ltd.		3,600		146,996
Tohoku Electric Power Co., Inc.		14,800		146,721
Tokio Marine Holdings, Inc.		31,000		1,735,652
Tokyo Century Corp.		2,300		122,461
Tokyo Electric Power Co. Holdings, Inc.(b)		84,800		362,991
Tokyo Electron Ltd.		7,700		1,681,141
Tokyo Gas Co. Ltd.		19,500		473,828
Tokyu Corp.		26,700		493,755
Tokyu Fudosan Holdings Corp.		30,800		212,683
Toppan Printing Co. Ltd.		11,500		237,570
Toray Industries, Inc.		70,000		474,286
Toshiba Corp.		24,400		828,178
Tosoh Corp.		10,700		164,842

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Japan (continued)
TOTO Ltd.		5,900	$	249,140
Toyo Seikan Group Holdings Ltd.		8,500		146,321
Toyo Suisan Kaisha Ltd.		5,400		229,315
Toyoda Gosei Co. Ltd.		4,300		107,368
Toyota Industries Corp.		8,000		460,320
Toyota Motor Corp.		107,906		7,603,215
Toyota Tsusho Corp.		10,200		358,302
Trend Micro, Inc.(b)		5,700		291,668
Tsuruha Holdings, Inc.		1,800		231,116
Unicharm Corp.		18,900		638,200
United Urban Investment Corp.		134		251,660
USS Co. Ltd.		12,100		228,730
Welcia Holdings Co. Ltd.		2,500		158,823
West Japan Railway Co.		8,200		709,247
Yakult Honsha Co. Ltd.		5,200		286,585
Yamada Denki Co. Ltd.		22,900		121,508
Yamaha Corp.		6,900		382,560
Yamaha Motor Co. Ltd.		11,600		232,382
Yamato Holdings Co. Ltd.		13,300		226,760
Yamazaki Baking Co. Ltd.		7,000		125,085
Yaskawa Electric Corp.		10,400		391,778
Yokogawa Electric Corp.		9,900		173,855
Yokohama Rubber Co. Ltd.		5,000		96,975
Z Holdings Corp.		127,000		536,208
ZOZO, Inc.		4,300		82,237
				173,323,483
Luxembourg — 0.1%
ArcelorMittal SA		28,352		499,553
Eurofins Scientific SE(a)		646		358,106
Reinet Investments SCA		5,889		116,679
SES SA		18,911		265,156
Tenaris SA		17,350		196,574
				1,436,068
Macau — 0.2%
Galaxy Entertainment Group Ltd.		96,000		706,715
Sands China Ltd.		124,000		662,541
SJM Holdings Ltd.		69,000		78,568
Wynn Macau Ltd.		73,600		181,359
				1,629,183
Malaysia — 0.5%
AirAsia Group Bhd		60,100		24,988
AMMB Holdings Bhd		68,900		65,900
Axiata Group Bhd		165,600		167,740
British American Tobacco Malaysia Bhd		5,800		21,397
CIMB Group Holdings Bhd		239,100		301,151
Dialog Group Bhd		142,134		120,132
DiGi.Com Bhd		144,300		157,503
Fraser & Neave Holdings BHD		12,300		104,763
Gamuda Bhd(b)		129,800		123,790
Genting Bhd		119,100		176,239
Genting Malaysia Bhd		106,100		85,402
Genting Plantations Bhd(a)		10,000		25,901
Hartalega Holdings Bhd		88,200		118,260
Hong Leong Bank Bhd		31,140		131,773
Hong Leong Financial Group Bhd		7,000		28,921
IHH Healthcare Bhd		143,000		191,459
IJM Corp. Bhd		126,600		67,213
IOI Corp. Bhd		102,200		115,232
Kuala Lumpur Kepong Bhd		17,500		106,182
Malayan Banking Bhd		204,800		432,778
Malaysia Airports Holdings Bhd		11,300		21,001
Maxis Bhd(a)		144,000		187,472
MISC Bhd		27,400		55,983

Security	Shares		Value
Malaysia (continued)
Nestle Malaysia Bhd		2,400	$	86,299
Petronas Chemicals Group Bhd		122,200		219,606
Petronas Dagangan Bhd		6,100		34,448
Petronas Gas Bhd		34,000		138,144
PPB Group Bhd		15,120		69,677
Press Metal Aluminium Holdings Bhd(a)		77,800		88,578
Public Bank Bhd		138,020		656,442
QL Resources Bhd		53,600		106,554
RHB Bank Bhd(e)		12,900		—
RHB Capital Bhd		82,424		116,468
Sime Darby Bhd		159,000		86,307
Sime Darby Plantation Bhd		159,000		211,917
Telekom Malaysia Bhd		55,900		52,228
Tenaga Nasional Bhd		141,300		458,307
Top Glove Corp. Bhd		111,900		128,641
Westports Holdings Bhd		70,000		72,122
YTL Corp. Bhd		115,423		27,657
				5,384,575
Mexico — 0.6%
Alfa SAB de CV, Series A		153,472		127,274
Alsea SAB de CV(b)		43,846		115,554
America Movil SAB de CV, Series L		1,646,060		1,314,584
Arca Continental SAB de CV		15,972		84,457
Cemex SAB de CV CPO		646,337		242,024
Coca-Cola Femsa SAB de CV		24,300		147,644
El Puerto de Liverpool SAB de CV, Series C1		10,900		54,144
Fibra Uno Administracion SA de CV		143,017		221,551
Fomento Economico Mexicano SAB de CV		96,869		915,382
Gruma SAB de CV, Class B		9,959		102,253
Grupo Aeroportuario del Pacifico SAB de CV, Class B		15,800		187,745
Grupo Aeroportuario del Sureste SAB de CV, Class B		10,700		200,356
Grupo Bimbo SAB de CV, Series A		46,764		85,156
Grupo Carso SAB de CV, Series A1		11,376		42,008
Grupo Financiero Banorte SAB de CV, Series O		129,547		723,874
Grupo Financiero Inbursa SAB de CV, Series O		99,700		122,282
Grupo Mexico SAB de CV, Series B		177,414		486,616
Grupo Televisa SAB CPO		109,894		257,887
Industrias Penoles SAB de CV		7,755		81,297
Infraestructura Energetica Nova SAB de CV		33,988		159,860
Kimberly-Clark de Mexico SAB de CV, Class A(b)		78,500		155,692
Megacable Holdings SAB de CV CPO		21,129		86,539
Orbia Advance Corp. SAB de CV		36,623		78,098
Promotora y Operadora de Infraestructura SAB de CV(b)		4,006		41,006
Wal-Mart de Mexico SAB de CV		251,351		719,855
				6,753,138
Netherlands — 3.1%
ABN AMRO Group NV CVA(d)		19,393		353,463
Adyen NV(b)(d)		459		377,571
Aegon NV		95,385		436,635
Akzo Nobel NV		10,504		1,072,710
Altice Europe NV, Class A(b)		33,037		213,931
ASML Holding NV		20,421		6,045,768
EXOR NV		5,704		442,239
Heineken Holding NV		5,886		572,075
Heineken NV		12,135		1,295,142
ING Groep NV		187,602		2,255,427
Koninklijke Ahold Delhaize NV		54,716		1,371,861
Koninklijke DSM NV		8,316		1,087,280
Koninklijke KPN NV		197,999		585,954
Koninklijke Philips NV		42,750		2,089,778
Koninklijke Vopak NV		4,260		231,490
NN Group NV		13,821		525,513
NXP Semiconductors NV(a)		13,246		1,685,686

SCHEDULE OF INVESTMENTS 29

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Netherlands (continued)
QIAGEN NV(b)		10,175	$	346,696
Randstad NV		6,023		369,060
Royal Dutch Shell PLC, B Shares		179,203		5,319,402
Royal Dutch Shell PLC, Class A		205,871		6,096,709
Wolters Kluwer NV		12,456		909,481
				33,683,871
New Zealand — 0.2%
a2 Milk Co. Ltd.(b)		39,580		400,762
Auckland International Airport Ltd.		55,568		327,539
Fisher & Paykel Healthcare Corp. Ltd.		27,280		408,271
Fletcher Building Ltd.		28,052		96,153
Mercury NZ Ltd.		24,362		82,872
Meridian Energy Ltd.		95,908		323,066
Ryman Healthcare Ltd.		13,399		147,263
Spark New Zealand Ltd.		83,974		244,869
				2,030,795
Norway — 0.4%
Aker BP ASA		5,988		196,528
DNB ASA		41,092		768,951
Equinor ASA		48,719		971,567
Gjensidige Forsikring ASA		10,710		224,813
Mowi ASA		20,651		536,945
Norsk Hydro ASA		62,662		233,015
Orkla ASA		34,581		350,679
Schibsted ASA, Class B		3,873		110,679
Telenor ASA		37,046		664,075
Yara International ASA		9,852		410,472
				4,467,724
Pakistan — 0.0%
Habib Bank Ltd.		10,100		10,267
MCB Bank Ltd.		6,700		8,866
Oil & Gas Development Co. Ltd.		11,100		10,218
				29,351
Peru — 0.1%
Compania de Minas Buenaventura SA — ADR		9,607		145,066
Credicorp Ltd.		3,324		708,444
Southern Copper Corp.		5,855		248,720
				1,102,230
Philippines — 0.3%
Aboitiz Equity Ventures, Inc.		70,570		71,646
Aboitiz Power Corp.		29,200		19,718
Ayala Corp.		13,480		208,795
Ayala Land, Inc.		317,200		284,500
Bank of the Philippine Islands		26,042		45,199
BDO Unibank, Inc.		93,622		292,078
Globe Telecom, Inc.		845		33,703
GT Capital Holdings, Inc.		3,701		61,896
International Container Terminal Services, Inc.		41,800		105,936
JG Summit Holdings, Inc.		156,443		249,331
Jollibee Foods Corp.		12,070		51,428
Manila Electric Co.		11,960		74,861
Megaworld Corp.		600,000		47,453
Metro Pacific Investments Corp.		584,000		40,129
Metropolitan Bank & Trust Co.		96,987		126,967
PLDT, Inc.		6,115		119,941
Security Bank Corp.		4,290		16,505
SM Investments Corp.		17,272		355,426
SM Prime Holdings, Inc.		486,150		403,509
Universal Robina Corp.		34,300		98,203
				2,707,224

Security	Shares		Value
Poland — 0.2%
Bank Millennium SA(b)		13,346	$	20,540
Bank Polska Kasa Opieki SA		7,442		196,941
CCC SA		981		28,442
CD Projekt SA		3,685		271,731
Cyfrowy Polsat SA		8,953		65,819
Dino Polska SA(b)(d)		1,416		53,727
Grupa Lotos SA		6,134		135,133
KGHM Polska Miedz SA(b)		7,250		182,881
LPP SA		55		127,863
mBank SA(b)		573		58,812
Orange Polska SA(b)		32,359		60,702
PGE Polska Grupa Energetyczna SA(b)		30,296		63,484
Polski Koncern Naftowy ORLEN SA		16,199		366,414
Polskie Gornictwo Naftowe i Gazownictwo SA		93,796		106,983
Powszechna Kasa Oszczednosci Bank Polski SA		49,247		447,096
Powszechny Zaklad Ubezpieczen SA		26,379		278,600
Santander Bank Polska SA		1,611		130,531
				2,595,699
Portugal — 0.1%
EDP — Energias de Portugal SA		122,176		530,169
Galp Energia SGPS SA		24,757		415,622
Jeronimo Martins SGPS SA		10,434		171,945
				1,117,736
Qatar — 0.2%
Barwa Real Estate Co.		25,480		24,619
Commercial Bank of Qatar QSC		100,850		129,626
Industries Qatar QSC		97,136		272,651
Masraf Al Rayan QSC		154,440		166,989
Mesaieed Petrochemical Holding Co.		245,102		167,979
Ooredoo QPSC		14,717		28,438
Qatar Electricity & Water Co. QSC		37,230		163,562
Qatar Fuel QSC		10,248		64,078
Qatar Insurance Co. SAQ		130,270		112,400
Qatar International Islamic Bank QSC		39,371		104,061
Qatar Islamic Bank SAQ		52,150		218,288
Qatar National Bank QPSC		209,500		1,178,501
				2,631,192
Romania — 0.0%
NEPI Rockcastle PLC		21,499		190,090
Russia — 1.1%
Alrosa PJSC		167,262		227,233
Evraz PLC		27,295		146,160
Gazprom PJSC		441,970		1,826,079
Gazprom PJSC — ADR		34,210		282,353
Inter RAO UES PJSC		1,289,334		104,867
LUKOIL PJSC		18,591		1,845,175
Magnit PJSC — GDR		14,687		177,052
Magnitogorsk Iron & Steel Works PJSC		206,260		139,493
MMC Norilsk Nickel PJSC		3,083		948,478
Mobile TeleSystems PJSC — ADR		25,223		256,013
Moscow ExchangeMICEX-RTS PJSC		63,850		110,847
Novatek PJSC — GDR		4,712		956,536
Novolipetsk Steel PJSC		57,306		132,813
Polymetal International PLC		7,461		116,643
Polyus PJSC		811		92,819
Rosneft Oil Co. PJSC		21,260		154,201
Rosneft Oil Co. PJSC, — GDR		29,564		214,632
Sberbank of Russia PJSC		398,027		1,634,753
Sberbank of Russia PJSC — ADR		28,426		468,303
Severstal PJSC		10,830		163,789
Surgutneftegas OJSC — ADR		9,276		75,090
Surgutneftegas PJSC		321,026		261,152

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Russia (continued)
Tatneft PJSC		75,164	$	920,793
VTB Bank PJSC		86,510,000		64,045
VTB Bank PJSC, — GDR		50,000		73,211
X5 Retail Group NV, — GDR		4,498		154,598
				11,547,128
Saudi Arabia — 0.7%
Advanced Petrochemical Co.		6,265		82,613
Al Rajhi Bank		61,370		1,070,182
Alinma Bank		38,749		261,843
Almarai Co. JSC		14,060		185,705
Arab National Bank		20,595		150,429
BankAl-Jazira		25,089		100,679
Bank AlBilad		11,600		83,150
Banque Saudi Fransi		25,272		255,339
Co. for Cooperative Insurance(b)		5,330		109,045
Dar Al Arkan Real Estate Development Co.(b)		26,789		78,614
Etihad Etisalat Co.(b)		14,520		96,749
Jarir Marketing Co.		2,022		89,266
National Commercial Bank		54,870		720,347
National Industrialization Co.(b)		33,697		122,925
Rabigh Refining & Petrochemical Co.(b)		18,941		109,404
Riyad Bank		55,131		352,853
Sahara International Petrochemical Co.		14,239		68,172
Samba Financial Group		46,040		398,326
Saudi Arabian Fertilizer Co.		8,326		172,031
Saudi Arabian Mining Co.(b)		20,212		239,305
Saudi Arabian Oil Co.(b)(d)		47,432		445,706
Saudi Basic Industries Corp.		37,584		941,522
Saudi British Bank		31,658		292,747
Saudi Cement Co.		5,582		104,310
Saudi Electricity Co.		40,008		215,648
Saudi Industrial Investment Group		15,022		96,141
Saudi Kayan Petrochemical Co.(b)		43,107		127,686
Saudi Telecom Co.		18,560		503,614
Savola Group(b)		12,960		118,672
Yanbu National Petrochemical Co.		12,736		190,073
				7,783,096
Singapore — 0.8%
Ascendas Real Estate Investment Trust		158,198		349,515
BOC Aviation Ltd.(d)		12,300		125,094
CapitaLand Commercial Trust		124,412		184,254
CapitaLand Ltd.		111,900		312,259
CapitaLand Mall Trust		134,200		245,662
City Developments Ltd.		17,400		141,616
ComfortDelGro Corp. Ltd.		98,300		173,933
DBS Group Holdings Ltd.		86,084		1,659,806
Genting Singapore Ltd.		233,000		159,556
Jardine Cycle & Carriage Ltd.		4,444		99,380
Keppel Corp. Ltd.(a)		63,000		317,430
Mapletree Commercial Trust		114,900		204,321
Oversea-Chinese Banking Corp. Ltd.		153,049		1,252,026
SATS Ltd.		24,800		93,350
Sembcorp Industries Ltd.(a)		40,000		68,120
Singapore Airlines Ltd.(a)		28,600		192,286
Singapore Exchange Ltd.		42,100		277,276
Singapore Press Holdings Ltd.		37,200		60,260
Singapore Technologies Engineering Ltd.		103,700		303,700
Singapore Telecommunications Ltd.		382,400		958,722
Suntec Real Estate Investment Trust		137,100		187,682
United Overseas Bank Ltd.		56,100		1,103,297
UOL Group Ltd.		22,000		136,158
Venture Corp. Ltd.		11,200		135,114
Wilmar International Ltd.		97,900		299,936
				9,040,753

Security	Shares		Value
South Africa — 1.4%
Absa Group, Ltd.		38,037	$	405,464
Anglo American Platinum Ltd.		2,774		258,927
Anglo American PLC		52,049		1,495,259
AngloGold Ashanti Ltd.		19,921		452,522
Aspen Pharmacare Holdings Ltd.(b)		18,439		157,253
Bid Corp. Ltd.		14,178		334,339
Bidvest Group Ltd.		15,555		227,417
Capitec Bank Holdings Ltd.		2,289		236,349
Clicks Group Ltd.		10,206		186,974
Discovery Ltd.		20,716		178,421
Exxaro Resources Ltd.		14,243		133,359
FirstRand Ltd.		153,955		690,793
Fortress REIT Ltd., Class A		67,528		92,859
Foschini Group Ltd.		6,728		71,865
Gold Fields Ltd.		38,623		263,627
Growthpoint Properties Ltd.		122,689		193,678
Impala Platinum Holdings Ltd.(b)		38,734		395,758
Investec Ltd.		7,549		44,760
Kumba Iron Ore Ltd.		2,943		87,561
Liberty Holdings Ltd.		1,922		15,184
Life Healthcare Group Holdings Ltd.		84,544		148,794
Momentum Metropolitan Holdings		20,454		31,895
Mr Price Group Ltd.		10,819		141,248
MTN Group Ltd.		83,776		493,872
MultiChoice Group Ltd.(b)		18,030		150,213
Naspers Ltd., Class N		21,024		3,440,512
Nedbank Group Ltd.		20,449		313,110
Northam Platinum Ltd.(b)		18,042		159,243
Old Mutual Ltd.		220,791		309,921
Pepkor Holdings Ltd.(a)(d)		88,345		113,979
Pick n Pay Stores Ltd.		28,036		127,889
PSG Group Ltd.		9,135		152,724
Rand Merchant Investment Holdings Ltd.		48,390		106,551
Redefine Properties Ltd.		238,334		128,645
Remgro Ltd.		22,131		308,601
RMB Holdings Ltd.		46,133		265,344
Sanlam Ltd.		86,962		491,325
Sasol Ltd.(b)		29,383		637,483
Shoprite Holdings Ltd.		21,012		188,983
Sibanye Gold Ltd.(b)		109,857		280,701
Spar Group Ltd.(a)		4,305		60,817
Standard Bank Group Ltd.		58,001		697,634
Telkom SA SOC Ltd.		11,210		27,908
Tiger Brands Ltd.		7,701		115,920
Vodacom Group Ltd.		34,594		284,784
Woolworths Holdings Ltd.		65,875		228,913
				15,329,378
South Korea — 3.0%
Amorepacific Corp.		1,381		237,832
Amorepacific Group		739		52,794
BGF retail Co. Ltd.		426		62,439
BNK Financial Group, Inc.		6,269		41,437
Celltrion Healthcare Co. Ltd.(b)		3,330		151,720
Celltrion, Inc.(b)		4,813		750,282
Cheil Worldwide, Inc.		4,081		84,870
CJ CheilJedang Corp.		487		106,189
CJ Corp.		848		70,708
CJ ENM Co. Ltd.		390		53,766
CJ Logistics Corp.(b)		414		55,403
Daelim Industrial Co. Ltd.		1,073		83,940
Daewoo Engineering & Construction Co. Ltd.(b)		19,237		78,796
Daewoo Shipbuilding & Marine Engineering Co. Ltd.(b)		3,397		81,517
DB Insurance Co. Ltd.		1,949		88,039
Doosan Bobcat, Inc.(b)		2,907		86,328

SCHEDULE OF INVESTMENTS 31

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
South Korea (continued)
E-MART Inc.		545	$	59,961
Fila Korea Ltd.		2,176		99,430
GS Engineering & Construction Corp.		4,772		127,708
GS Holdings Corp.		2,934		130,897
GS Retail Co. Ltd.		2,671		90,665
Hana Financial Group, Inc.		13,571		431,666
Hankook Tire & Technology Co. Ltd.		4,552		131,822
Hanmi Pharm Co. Ltd.		234		59,813
Hanon Systems		14,702		141,525
Hanwha Chemical Corp.		4,037		65,629
Hanwha Corp.		1,508		32,523
Hanwha Life Insurance Co. Ltd.		7,120		14,192
HDC Hyundai DevelopmentCo-Engineering & Construction, Class E(b)		1,311		28,988
Helixmith Co. Ltd.(b)		780		62,144
HLB, Inc.(b)		1,313		130,534
Hotel Shilla Co. Ltd.		1,174		91,760
Hyundai Department Store Co. Ltd.		314		22,517
Hyundai Engineering & Construction Co. Ltd.		3,298		120,309
Hyundai Glovis Co. Ltd.		1,004		123,879
Hyundai Heavy Industries Holdings Co. Ltd.(b)		422		123,160
Hyundai Marine & Fire Insurance Co. Ltd.		4,560		106,133
Hyundai Mobis Co. Ltd.		3,088		683,191
Hyundai Motor Co.		7,139		743,576
Hyundai Steel Co.		3,455		93,672
Industrial Bank of Korea		10,461		106,632
Kakao Corp.		2,067		273,763
Kangwon Land, Inc.		3,796		97,109
KB Financial Group, Inc.		19,323		796,068
KCC Corp.		266		51,783
Kia Motors Corp.		13,557		517,749
KMW Co. Ltd.(b)		2,491		109,951
Korea Aerospace Industries Ltd.		2,844		83,704
Korea Electric Power Corp.		10,419		249,979
Korea Gas Corp.		753		24,605
Korea Investment Holdings Co. Ltd.		1,486		92,803
Korea Shipbuilding & Offshore Engineering Co. Ltd.(b)		1,655		180,088
Korea Zinc Co. Ltd.		398		146,255
Korean Air Lines Co. Ltd.		4,193		103,090
KT&G Corp.		6,257		506,238
Kumho Petrochemical Co. Ltd.		423		28,289
LG Chem Ltd.		2,257		618,541
LG Corp.		4,097		261,050
LG Display Co. Ltd.		10,040		140,461
LG Electronics, Inc.		4,945		307,169
LG Household & Health Care Ltd.		441		479,037
LG Innotek Co. Ltd.		809		97,509
LG Uplus Corp.		5,800		71,139
Lotte Chemical Corp.		865		167,121
Lotte Corp.		2,177		73,172
Lotte Shopping Co. Ltd.		260		30,418
Medy-Tox, Inc.		347		90,240
Meritz Securities Co. Ltd.		25,240		82,508
Mirae Asset Daewoo Co. Ltd.		9,107		59,252
NAVER Corp.		6,346		1,021,039
NCSoft Corp.		791		369,085
Netmarble Corp.(b)(d)		1,516		120,882
NH Investment & Securities Co. Ltd.		5,312		58,109
OCI Co. Ltd.		1,017		54,954
Orange Life Insurance Ltd.(d)		2,814		68,668
Orion Corp.		907		82,719
Pan Ocean Co. Ltd.(b)		23,834		93,391
Pearl Abyss Corp.(b)		511		81,866
POSCO		3,587		729,107

Security	Shares		Value
South Korea (continued)
POSCO Chemtech Co. Ltd.		1,891	$	80,355
Posco International Corp.		1,160		18,661
S-1 Corp.		442		35,813
S-Oil Corp.		2,657		218,224
Samsung Biologics Co. Ltd.(b)(d)		698		260,479
Samsung C&T Corp.		4,015		375,907
Samsung Card Co. Ltd.		1,210		40,387
Samsung Electro-Mechanics Co. Ltd.		3,162		340,108
Samsung Electronics Co. Ltd.		228,742		11,022,355
Samsung Engineering Co. Ltd.(b)		6,952		114,890
Samsung Fire & Marine Insurance Co. Ltd.		1,332		280,034
Samsung Heavy Industries Co. Ltd.(b)		24,292		152,120
Samsung Life Insurance Co. Ltd.		3,145		202,191
Samsung SDI Co. Ltd.		2,894		589,546
Samsung SDS Co. Ltd.		1,413		237,137
Samsung Securities Co. Ltd.		2,723		90,690
Shinhan Financial Group Co. Ltd.		22,963		860,947
Shinsegae Inc.		335		83,512
SK Holdings Co. Ltd.		2,034		458,867
SK Hynix, Inc.		26,446		2,151,058
SK Innovation Co. Ltd.		2,988		386,699
SK Telecom Co. Ltd.		831		171,226
Woongjin Coway Co. Ltd.		2,504		201,585
Woori Financial Group, Inc.		13,531		135,473
Yuhan Corp.		370		75,508
				32,911,069
Spain — 1.8%
ACS Actividades de Construccion y Servicios SA		12,585		504,836
Aena SME SA(d)		3,059		586,465
Amadeus IT Group SA		21,424		1,754,556
AmRest Holdings SE(b)		9,392		107,192
Banco Bilbao Vizcaya Argentaria SA		308,392		1,731,413
Banco de Sabadell SA		320,185		374,907
Banco Santander SA		785,801		3,294,244
Bankia SA		45,598		97,632
Bankinter SA		28,922		212,438
CaixaBank SA		176,221		554,930
Cellnex Telecom SA(d)		11,485		495,412
Enagas SA		6,964		177,634
Endesa SA		16,138		430,961
Ferrovial SA		25,032		758,398
Grifols SA		14,947		528,099
Iberdrola SA		287,241		2,960,181
Industria de Diseno Textil SA		52,193		1,844,527
Mapfre SA		66,978		177,595
Naturgy Energy Group SA		14,485		364,747
Red Electrica Corp. SA		20,753		418,168
Repsol SA		67,863		1,066,138
Siemens Gamesa Renewable Energy SA		10,554		185,863
Telefonica SA		225,025		1,573,623
				20,199,959
Sweden — 1.6%
Alfa Laval AB		15,879		399,901
Assa Abloy AB, Class B		48,658		1,137,403
Atlas Copco AB, A Shares		31,846		1,271,154
Atlas Copco AB, Class B		18,943		657,721
Boliden AB		15,022		398,964
Electrolux AB, Class B		12,152		298,737
Epiroc AB, Class A		32,873		402,012
Epiroc AB, Class B		15,828		188,111
Essity AB, Class B		30,180		971,984
Hennes & Mauritz AB, Class B		40,736		830,914
Hexagon AB, Class B		13,062		732,142

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Sweden (continued)
Husqvarna AB, Class B		14,305	$	114,636
ICA Gruppen AB		4,800		224,217
Industrivarden AB, Class C		8,883		214,218
Investor AB, Class B		21,024		1,147,780
Kinnevik AB		10,274		251,765
L E Lundbergforetagen AB, B Shares		3,263		143,241
Lundin Petroleum AB		9,142		310,411
Sandvik AB		55,123		1,073,650
Securitas AB, Class B		13,331		229,683
Skandinaviska Enskilda Banken AB, Class A		81,350		765,005
Skanska AB, Class B		16,387		370,700
SKF AB, Class B		17,305		350,363
Svenska Handelsbanken AB, Class A		73,175		788,113
Swedbank AB, Class A		41,522		617,265
Swedish Match AB		8,807		453,708
Tele2 AB, Class B		26,650		386,799
Telefonaktiebolaget LM Ericsson, Class B		142,056		1,241,258
Telia Co. AB		121,784		523,248
Volvo AB, Class B		65,184		1,091,258
				17,586,361
Switzerland — 6.3%
ABB Ltd., Registered Shares		89,871		2,167,970
Adecco Group AG, Registered Shares		7,309		462,091
Alcon, Inc.(b)		20,166		1,142,235
Baloise Holding AG, Registered Shares		2,613		472,915
Barry Callebaut AG, Registered Shares		140		309,048
Chocoladefabriken Lindt & Spruengli AG		47		364,957
Chocoladefabriken Lindt & Spruengli AG, Registered Shares		6		530,068
Cie Financiere Richemont SA, Registered Shares		25,390		1,984,251
Clariant AG, Registered Shares(b)		8,166		182,497
Coca-Cola HBC AG(b)		8,806		299,316
Credit Suisse Group AG, Registered Shares(b)		125,552		1,697,171
Dufry AG, Registered Shares(b)		1,558		154,493
EMS-Chemie Holding AG, Registered Shares		450		295,846
Geberit AG, Registered Shares		1,722		966,527
Givaudan SA, Registered Shares		438		1,372,252
Glencore PLC(b)		536,352		1,670,048
Julius Baer Group Ltd.(b)		11,200		577,393
Kuehne + Nagel International AG, Registered Shares		2,676		451,352
LafargeHolcim Ltd., Registered Shares(b)		24,216		1,343,442
Lonza Group AG, Registered Shares(b)		3,652		1,332,276
Nestle SA, Registered Shares		140,804		15,244,173
Novartis AG, Registered Shares		101,755		9,635,137
Pargesa Holding SA, Bearer Shares		1,995		165,747
Partners Group Holding AG		838		768,050
Roche Holding AG		33,297		10,821,613
Schindler Holding AG, Participation Certificates		2,234		568,109
Schindler Holding AG, Registered Shares		757		185,383
SGS SA, Registered Shares		229		627,156
Sika AG, Registered Shares		6,216		1,167,336
Sonova Holding AG, Registered Shares		2,722		622,272
STMicroelectronics NV		35,181		949,205
Straumann Holding AG, Registered Shares		478		468,886
Swatch Group AG, Bearer Shares		1,402		391,446
Swatch Group AG, Registered Shares		1,924		101,779
Swiss Life Holding AG, Registered Shares		1,632		818,726
Swiss Prime Site AG, Registered Shares(b)		3,413		394,864
Swiss Re AG		13,984		1,570,996
Swisscom AG, Registered Shares		1,157		612,488
Temenos AG, Registered Shares(b)		3,464		547,967
UBS Group AG, Registered Shares(b)		188,783		2,382,326
Vifor Pharma AG		2,169		395,854
Zurich Insurance Group AG		7,251		2,974,354
				69,190,015

Security	Shares		Value
Taiwan — 3.2%
Accton Technology Corp.		27,000	$	151,565
Acer, Inc.		69,504		41,426
Advantech Co. Ltd.		11,873		119,724
Airtac International Group		8,000		125,048
ASE Technology Holding Co. Ltd.		186,343		519,357
Asia Cement Corp.		94,233		150,838
Asustek Computer, Inc.		38,220		294,976
AU Optronics Corp.		414,000		138,645
Catcher Technology Co. Ltd.		27,000		204,509
Cathay Financial Holding Co. Ltd.		347,488		493,388
Chailease Holding Co. Ltd.		67,423		310,809
Chang Hwa Commercial Bank Ltd.		234,686		177,840
Cheng Shin Rubber Industry Co. Ltd.		66,436		92,671
Chicony Electronics Co. Ltd.		15,856		47,119
China Airlines Ltd.		103,687		31,339
China Development Financial Holding Corp.		577,765		187,662
China Life Insurance Co. Ltd.(b)		132,016		112,709
China Steel Corp.		580,638		463,281
Chunghwa Telecom Co. Ltd.		185,000		678,656
Compal Electronics, Inc.		192,000		120,933
CTBC Financial Holding Co. Ltd.		820,601		613,926
Delta Electronics, Inc.		86,000		435,192
E.Sun Financial Holding Co. Ltd.		443,315		413,132
Eclat Textile Co. Ltd.		7,303		98,309
Eva Airways Corp.		83,492		38,294
Evergreen Marine Corp. Taiwan Ltd.(b)		109,139		45,225
Far Eastern New Century Corp.		200,607		199,797
Far EasTone Telecommunications Co. Ltd.		95,000		228,489
Feng TAY Enterprise Co. Ltd.		17,765		115,624
First Financial Holding Co. Ltd.		484,461		383,344
Formosa Chemicals & Fibre Corp.		161,360		471,428
Formosa Petrochemical Corp.		50,000		162,623
Formosa Plastics Corp.		225,040		749,473
Formosa Taffeta Co. Ltd.		31,000		35,364
Foxconn Technology Co. Ltd.		43,007		95,081
Fubon Financial Holding Co. Ltd.		278,952		431,994
Giant Manufacturing Co. Ltd.		10,000		71,187
Globalwafers Co. Ltd.		8,000		102,451
Highwealth Construction Corp.		62,400		96,437
Hiwin Technologies Corp.		12,396		116,311
Hon Hai Precision Industry Co. Ltd.		604,800		1,834,669
Hotai Motor Co. Ltd.		13,000		296,234
Hua Nan Financial Holdings Co. Ltd.		436,123		320,331
Innolux Corp.		428,494		119,318
Inventec Corp.		92,470		70,571
Largan Precision Co. Ltd.		5,000		835,191
Lite-On Technology Corp.		99,816		164,342
MediaTek, Inc.		77,255		1,144,693
Mega Financial Holding Co. Ltd.		505,110		515,778
Micro-Star International Co. Ltd.		37,000		106,980
Nan Ya Plastics Corp.		262,790		638,619
Nanya Technology Corp.		50,000		139,929
Nien Made Enterprise Co. Ltd.		9,000		83,254
Novatek Microelectronics Corp.		23,000		168,521
Pegatron Corp.		110,000		251,560
Phison Electronics Corp.		4,000		45,500
Pou Chen Corp.		92,000		120,344
Powertech Technology, Inc.		31,100		103,507
President Chain Store Corp.		26,000		264,021
Quanta Computer, Inc.		138,000		296,440
Realtek Semiconductor Corp.		23,240		182,625
Ruentex Development Co. Ltd.(b)		34,384		51,890
Ruentex Industries Ltd.(b)		10,512		25,805
Shanghai Commercial & Savings Bank Ltd.		166,512		289,414

SCHEDULE OF INVESTMENTS 33

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Taiwan (continued)
Shin Kong Financial Holding Co. Ltd.(b)		620,244	$	214,354
SinoPac Financial Holdings Co. Ltd.		547,741		237,620
Standard Foods Corp.		7,342		17,061
Synnex Technology International Corp.		58,500		73,209
Taishin Financial Holding Co. Ltd.		356,976		172,773
Taiwan Business Bank		285,886		120,260
Taiwan Cement Corp.		243,859		355,707
Taiwan Cooperative Financial Holding Co. Ltd.		447,056		309,426
Taiwan High Speed Rail Corp.		142,000		182,058
Taiwan Mobile Co. Ltd.		67,800		253,314
Taiwan Semiconductor Manufacturing Co. Ltd.		1,180,000		13,060,033
Tatung Co. Ltd.(b)		45,000		31,609
Uni-President Enterprises Corp.		249,950		619,833
United Microelectronics Corp.		527,000		288,769
Vanguard International Semiconductor Corp.		38,000		100,524
Walsin Technology Corp.		13,000		103,768
Win Semiconductors Corp.		16,000		157,656
Winbond Electronics Corp.		163,000		106,524
Wistron Corp.		133,161		126,067
Wiwynn Corp.		6,000		126,848
WPG Holdings Ltd.		78,448		102,360
Yageo Corp.		10,783		157,097
Yuanta Financial Holding Co. Ltd.		432,260		291,407
Zhen Ding Technology Holding Ltd.		37,710		180,935
				34,824,924
Thailand — 0.7%
Advanced Info Service PCL — NVDR		62,600		444,512
Airports of Thailand PCL — NVDR		214,700		531,463
B Grimm Power PCL		64,900		113,540
Bangkok Bank PCL, Foreign Registered Shares		25,100		133,558
Bangkok Dusit Medical Services PCL, NVDR		432,400		374,764
Banpu PCL — NVDR		227,900		90,402
BTS Group Holdings PCL — NVDR		513,400		225,988
Bumrungrad Hospital PCL — NVDR		22,400		109,810
Central Pattana PCL — NVDR		102,400		212,234
Charoen Pokphand Foods PCL — NVDR		204,000		187,014
CP ALL PCL — NVDR		292,800		705,522
Energy Absolute PCL — NVDR		98,300		143,190
Global Power Synergy PCL		42,200		120,583
Home Product Center PCL — NVDR		339,932		181,293
Indorama Ventures PCL — NVDR		97,000		113,052
IRPC PCL — NVDR		492,400		60,370
Kasikornbank PCL — NVDR		35,100		176,699
Kasikornbank PCL, Foreign Registered Shares		58,200		292,324
Krung Thai Bank PCL — NVDR		285,275		156,102
Land & Houses PCL — NVDR		601,300		196,663
Minor International PCL — NVDR		146,680		176,045
Osotspa PCL		81,600		110,129
PTT Exploration & Production PCL — NVDR		76,522		317,592
PTT Global Chemical PCL — NVDR		115,068		218,639
PTT PCL — NVDR		593,200		870,399
Siam Cement PCL — NVDR		42,200		551,568
Siam Commercial Bank PCL — NVDR		41,800		169,978
Srisawad Corp. PCL, NVDR		53,800		122,726
Thai Oil PCL — NVDR		51,600		119,941
Thai Union Group PCL — NVDR		231,400		104,100
TMB Bank PCL — NVDR(a)		2,462,549		137,917
True Corp. PCL — NVDR		783,140		119,932
				7,588,049
Turkey — 0.1%
Akbank TAS(b)		148,211		201,881
Anadolu Efes Biracilik Ve Malt Sanayii AS		14,158		54,928
Arcelik AS(b)		20,968		73,430

Security	Shares		Value
Turkey (continued)
BIM Birlesik Magazalar AS		17,408	$	136,537
Eregli Demir ve Celik Fabrikalari TAS		51,754		78,599
Ford Otomotiv Sanayi AS		2,700		32,147
Haci Omer Sabanci Holding AS		32,457		52,056
KOC Holding AS		17,992		61,488
TAV Havalimanlari Holding AS		2,171		10,641
Tupras Turkiye Petrol Rafinerileri AS		5,076		108,155
Turk Hava Yollari AO(b)		26,638		64,708
Turkcell Iletisim Hizmetleri AS		33,444		77,567
Turkiye Garanti Bankasi AS(b)		101,489		190,071
Turkiye Is Bankasi AS, Class C(b)		88,347		95,144
				1,237,352
United Arab Emirates — 0.2%
Abu Dhabi Commercial Bank PJSC		124,127		267,995
Aldar Properties PJSC		145,452		85,612
DP World PLC		10,522		137,935
Dubai Islamic Bank PJSC		48,113		72,214
Emaar Malls PJSC		81,000		40,355
Emaar Properties PJSC		172,958		189,494
Emirates Telecommunications Group Co. PJSC		97,764		435,435
First Abu Dhabi Bank PJSC		142,970		591,172
NMC Health PLC(a)		4,897		114,734
				1,934,946
United Kingdom — 9.3%
3i Group PLC		50,300		731,951
Admiral Group PLC		8,197		250,487
Ashtead Group PLC		20,678		661,173
Associated British Foods PLC		19,083		656,472
AstraZeneca PLC		62,556		6,261,351
Auto Trader Group PLC(d)		41,090		324,494
Aveva Group PLC		2,132		131,529
Aviva PLC		190,722		1,058,611
BAE Systems PLC		157,882		1,182,112
Barclays PLC		823,645		1,963,960
Barratt Developments PLC		54,522		539,846
Berkeley Group Holdings PLC		6,196		398,789
BP PLC		973,780		6,125,858
British American Tobacco PLC		110,286		4,687,383
British Land Co. PLC		46,491		393,386
BT Group PLC		402,928		1,026,737
Bunzl PLC		15,074		412,285
Burberry Group PLC		20,166		588,758
Centrica PLC		236,230		279,429
CK Hutchison Holdings Ltd.		134,508		1,282,599
CNH Industrial NV		47,161		517,823
Coca-Cola European Partners PLC		12,354		628,572
Compass Group PLC		75,703		1,897,251
Croda International PLC		7,217		490,241
DCC PLC		4,703		407,934
Diageo PLC		113,721		4,791,823
Direct Line Insurance Group PLC		67,525		279,388
easyJet PLC		9,017		169,852
Experian PLC		41,837		1,418,251
Fiat Chrysler Automobiles NV		50,913		754,863
G4S PLC		67,608		195,513
GlaxoSmithKline PLC		238,318		5,599,764
GVC Holdings PLC		31,705		371,332
Halma PLC		19,594		548,684
Hargreaves Lansdown PLC		12,676		325,155
HSBC Holdings PLC		951,477		7,448,576
Imperial Brands PLC		45,774		1,132,462
Informa PLC		65,336		743,107
InterContinental Hotels Group PLC		8,582		589,710

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
United Kingdom (continued)
Intertek Group PLC		8,502	$	658,804
ITV PLC		151,643		303,403
J. Sainsbury PLC		72,193		220,134
JD Sports Fashion PLC		18,108		201,136
Johnson Matthey PLC		7,947		315,984
Kingfisher PLC		97,026		279,311
Land Securities Group PLC		31,499		413,472
Legal & General Group PLC		278,803		1,119,967
Lloyds Banking Group PLC		3,394,391		2,811,983
London Stock Exchange Group PLC		14,615		1,502,012
M&G PLC(b)		113,634		357,032
Marks & Spencer Group PLC		78,862		223,610
Meggitt PLC		30,833		268,554
Melrose Industries PLC		251,292		800,421
Micro Focus International PLC		16,756		235,181
Mondi PLC		20,721		485,890
National Grid PLC		163,220		2,039,787
Next PLC		6,073		565,898
Ocado Group PLC(b)		25,479		432,302
Pearson PLC		33,637		284,169
Persimmon PLC		15,288		546,074
Prudential PLC		123,343		2,363,330
Reckitt Benckiser Group PLC		33,956		2,758,194
RELX PLC		93,038		2,348,589
Rentokil Initial PLC		86,686		519,558
Rolls-Royce Holdings PLC(b)		77,832		703,446
Royal Bank of Scotland Group PLC		228,688		733,618
RSA Insurance Group PLC		43,531		326,252
Sage Group PLC		45,514		451,530
Schroders PLC		4,883		215,614
Segro PLC		52,735		627,940
Severn Trent PLC		12,635		420,918
Smith & Nephew PLC		40,470		975,357
Smiths Group PLC		19,423		433,815
Spirax-Sarco Engineering PLC		3,836		451,549
SSE PLC		50,232		958,037
St. James’s Place PLC		24,806		382,378
Standard Chartered PLC		130,975		1,234,189
Standard Life Aberdeen PLC		123,732		538,311
Taylor Wimpey PLC		136,947		351,142
Tesco PLC		470,700		1,590,793
Unilever NV		70,840		4,065,555
Unilever PLC		54,061		3,094,594
United Utilities Group PLC		36,750		459,886
Vodafone Group PLC		1,279,760		2,484,492
Weir Group PLC		9,549		190,980
Whitbread PLC		5,907		379,103
WM Morrison Supermarkets PLC		100,540		266,084
WPP PLC		56,654		797,250
				101,455,139
United States — 0.3%
Bausch Health Cos., Inc.(b)		13,560		405,897
Carnival PLC		8,973		430,107
CyberArk Software Ltd.(b)		1,512		176,269
Ferguson PLC		11,242		1,023,099
James Hardie Industries PLC		19,386		378,889
JBS SA		60,731		389,504
Titan Cement International SA(b)		1,660		35,304
				2,839,069
Zambia — 0.0%
First Quantum Minerals Ltd.		29,878		303,025
Total Common Stocks — 97.3% (Cost — $850,277,543)				1,065,405,025

Security	Shares		Value
Preferred Stocks — 1.3%
Brazil — 0.7%
Banco Bradesco SA, Preference Shares, 0.00%		189,154	$	1,700,773
Braskem SA, Preference ‘A’ Shares, Class A, 0.00%		11,000		81,624
Centrais Eletricas Brasileiras SA, Preference ‘B’ Shares, 0.00%		9,817		93,321
Cia Brasileira de Distribuicao, Preference Shares, 0.00%		7,649		166,663
Cia Energetica de Minas Gerais, Preference Shares, 0.00%		34,268		117,472
Gerdau SA, Preference Shares, 0.00%		52,056		258,811
Itau Unibanco Holding SA, Preference Shares, 0.00%		230,644		2,127,152
Itausa — Investimentos Itau SA, Preference Shares, 0.00%		214,928		752,812
Lojas Americanas SA, Preference Shares, 0.00%		35,184		226,618
Petroleo Brasileiro SA, Preference Shares, 0.00%		199,768		1,498,744
Telefonica Brasil SA, Preference Shares, 0.00%		19,455		280,409
				7,304,399
Chile — 0.0%
Embotelladora Andina SA, Preference ‘B’ Shares, 0.00%		9,220		26,718
Sociedad Quimica y Minera de Chile SA, Preference ‘B’ Shares, 0.00%		4,912		131,365
				158,083
Colombia — 0.0%
Bancolombia SA, Preference Shares, 0.00%		21,944		305,739
Grupo Aval Acciones y Valores SA, Preference Shares, 0.00%		125,734		55,844
				361,583
Germany — 0.4%
Bayerische Motoren Werke AG, Preference Shares, 0.00%		3,454		212,635
Fuchs Petrolub SE, Preference Shares, 0.00%		3,377		167,781
Henkel AG & Co. KGaA, Preference Shares, 0.00%		8,690		897,681
Porsche Automobil Holding SE, Preference Shares, 0.00%		7,705		571,697
Sartorius AG, Preference Shares, 0.00%		1,605		343,088
Volkswagen AG, Preference Shares, 0.00%		8,774		1,727,060
				3,919,942
Russia — 0.0%
Surgutneftegas PJSC, Preference Shares, 0.00%		217,007		132,135
Transneft PJSC, Preference Shares, 0.00%		32		91,129
				223,264
South Korea — 0.2%
Amorepacific Corp., Preference Shares, 0.00%		382		29,513
Hyundai Motor Co., Preference Shares, 0.00%		852		52,770
Hyundai Motor Co., Second Preference Shares, 0.00%		1,756		120,465
LG Chem Ltd., Preference Shares, 0.00%		179		26,741
LG Household & Health Care Ltd. Preference Shares, 0.00%		151		100,603
Samsung Electronics Co. Ltd., Preference Shares, 0.00%		40,382		1,581,030
				1,911,122
Total Preferred Stocks — 1.3% (Cost — $10,224,710)				13,878,393
Rights — 0.0%
Brazil — 0.0%
Lojas Americanas SA (Expires 02/01/20)(b)		339		792
India — 0.0%
Piramal Enterprises Ltd. (Expires 01/20/20)		625		1,957
Spain — 0.0%
Repsol SA, (Expires 01/21/20)(b)		67,863		32,200
Total Rights — 0.0% (Cost — $32,093)				34,949

SCHEDULE OF INVESTMENTS 35

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Warrants — 0.0%
Thailand — 0.0%
BTS Group Holdings PCL — NVDR (Expires 02/06/21)		51,340	$	—
Total Warrants — 0.0% (Cost — $—)				—
Total Long-Term Investments — 98.6% (Cost — $860,534,346)				1,079,318,367
Short-Term Securities — 2.8%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(f)(g)(h)		18,171,935		18,179,204
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(f)(h)		13,177,912		13,177,912
Total Short-Term Securities — 2.8% (Cost — $31,352,898)				31,357,116
Total Investments — 101.4% (Cost — $891,887,244)				1,110,675,483
Liabilities in Excess of Other Assets — (1.4)%				(15,767,966	)
Net Assets — 100.0%			$	1,094,907,517

^(a)  Security, or a portion of the security, is on loan.

^(b)  Non-income producing security.

^(c)  A security contractually bound to one or more other securities to form a single saleable unit which cannot be sold separately.

^(d)  Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

^(e)  Security is valued using significant unobservable inputs and is classified as Level 3 in the fair value hierarchy.

^(f)  Annualized7-day yield as of period end.

^(g)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(h)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliate	Shares Held at 12/31/18		Net Activity			Shares Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)		Change in Unrealized Appreciation (Depreciation)
BlackRock Cash Funds: Institutional, SL Agency Shares		26,138,501		(7,966,566	)		18,171,935	$	18,179,204	$	276,682	(b)	$	13,030	$	1,944
BlackRock Cash Funds: Treasury, SL Agency Shares		2,472,228		10,705,684			13,177,912		13,177,912		149,167			—		—
								$	31,357,116	$	425,849		$	13,030	$	1,944

^(a)  Includes net capital gain distributions, if applicable.

^(b)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value / Unrealized Appreciation (Depreciation)
Long Contracts
S&P/TSX 60 Index		28		03/19/20	$	1,091	$	(2,903	)
E-Mini MSCI EAFE Index		86		03/20/20		8,757		22,683
MSCI Emerging Markets Index		38		03/20/20		2,128		5,950
							$	25,730

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statement of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Future contracts
Unrealized appreciation on future contracts(a)	$	—		—	$	28,633	$	—	$	—	$	—	$	28,633
Liabilities — Derivative Financial Instruments
Future contracts
Unrealized depreciation on future contracts(a)	$	—		—	$	2,903	$	—	$	—	$	—	$	2,903

^(a)  Includes cumulative appreciation (depreciation) on futures contracts, if any, as reported in the Schedule of Investments. Only current day’s variation margin is reported within the Statement of Assets and Liabilities.

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statement of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Future contracts	$	—	$	—	$	1,424,955	$	—	$	—	$	—	$	1,424,955
Net Change in Unrealized Appreciation (Depreciation) on:
Future contracts	$	—	$	—	$	127,831	$	—	$	—	$	—	$	127,831

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	11,469,563

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Common Stocks:
Argentina	$	454,137	$	—	$	—	$	454,137
Australia		—		53,561,944		—		53,561,944
Austria		143,479		1,473,643		—		1,617,122
Belgium		126,952		6,959,430		—		7,086,382
Brazil		14,617,568		—		—		14,617,568
Canada		71,264,982		—		—		71,264,982
Chile		2,049,529		340,981		—		2,390,510
China		28,252,972		75,355,150		211		103,608,333
Colombia		687,053		223,936		—		910,989
Czech Republic		219,442		235,194		—		454,636
Denmark		4,552,898		8,587,937		—		13,140,835
Egypt		260,476		—		—		260,476
Finland		1,059,617		6,896,516		—		7,956,133
France		2,459,803		76,854,366		—		79,314,169
Germany		4,806,722		52,718,954		—		57,525,676
Greece		96,880		797,429		2		894,311
Hong Kong		620,763		21,508,073		411		22,129,247
Hungary		67,312		743,773		—		811,085
India		9,515,741		16,261,855		—		25,777,596
Indonesia		—		5,784,549		—		5,784,549

SCHEDULE OF INVESTMENTS 37

Schedule of Investments  (continued) December 31, 2019 Total International ex U.S. Index Master Portfolio

	Level 1			Level 2		Level 3		Total
Ireland	$	2,439,600		$	2,095,108	$	—	$	4,534,708
Israel		1,436,805			2,491,917		—		3,928,722
Italy		—			14,528,293		—		14,528,293
Japan		—			173,323,483		—		173,323,483
Luxembourg		739,941			696,127		—		1,436,068
Macau		—			1,629,183		—		1,629,183
Malaysia		422,744			4,961,831		—		5,384,575
Mexico		6,753,138			—		—		6,753,138
Netherlands		1,685,686			31,998,185		—		33,683,871
New Zealand		—			2,030,795		—		2,030,795
Norway		—			4,467,724		—		4,467,724
Pakistan		19,133			10,218		—		29,351
Peru		1,102,230			—		—		1,102,230
Philippines		792,754			1,914,470		—		2,707,224
Poland		452,338			2,143,361		—		2,595,699
Portugal		—			1,117,736		—		1,117,736
Qatar		1,270,009			1,361,183		—		2,631,192
Romania		—			190,090		—		190,090
Russia		1,820,501			9,726,627		—		11,547,128
Saudi Arabia		1,034,766			6,748,330		—		7,783,096
Singapore		—			9,040,753		—		9,040,753
South Africa		3,493,058			11,836,320		—		15,329,378
South Korea		425,093			32,485,976		—		32,911,069
Spain		373,588			19,826,371		—		20,199,959
Sweden		765,005			16,821,356		—		17,586,361
Switzerland		895,025			68,294,990		—		69,190,015
Taiwan		253,314			34,571,610		—		34,824,924
Thailand		—			7,588,049		—		7,588,049
Turkey		191,465			1,045,887		—		1,237,352
United Arab Emirates		475,790			1,459,156		—		1,934,946
United Kingdom		3,115,542			98,339,597		—		101,455,139
United States		1,006,974			1,832,095		—		2,839,069
Zambia		303,025			—		—		303,025
Preferred Stocks		7,915,195			5,963,198		—		13,878,393
Rights		32,992			1,957		—		34,949
Short-Term Securities		31,357,116			—		—		31,357,116
	$	211,829,153		$	898,845,706	$	624	$	1,110,675,483
Derivative Financial Instruments(a)
Assets:
Equity contracts	$	28,633		$	—	$	—	$	28,633
Liabilities:
Equity contracts		(2,903	)		—		—		(2,903	)
	$	25,730		$	—	$	—	$	25,730

^(a)  Derivative financial instruments are futures contracts. Futures contracts are valued at the unrealized appreciation (depreciation) on the instrument.

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	Total International ex U.S. Index Master Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $16,023,002, cost — $860,534,346)	$	1,079,318,367
Investments at value — affiliated (cost — $31,352,898)		31,357,116
Cash pledged for futures contracts		440,620
Foreign currency at value (cost — $1,250,832)		1,258,544
Receivables:
Investments sold		94,902
Securities lending income — affiliated		17,270
Contributions from investors		3,307,955
Dividends — unaffiliated		1,525,870
Interest — unaffiliated		10,974
Variation margin on futures contracts		48,323
Prepaid expenses		2,926
Total assets		1,117,382,867
LIABILITIES
Cash collateral on securities loaned at value		18,156,083
Payables:
Investments purchased		3,853,563
Deferred foreign capital gain tax		84,652
Investment advisory fees		51,732
Other accrued expenses		323,171
Trustees’ fees		5,141
Variation margin on futures contracts		1,008
Total liabilities		22,475,350
NET ASSETS	$	1,094,907,517
NET ASSETS CONSIST OF
Investors’ capital	$	876,027,390
Net unrealized appreciation (depreciation)		218,880,127
NET ASSETS	$	1,094,907,517

See notes to financial statements.

FINANCIAL STATEMENTS 39

Statement of Operations

Year Ended December 31, 2019

	Total International ex U.S. Index Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	149,167
Dividends — unaffiliated		29,752,204
Securities lending income — affiliated — net		276,682
Non-cash dividends — unaffiliated		2,245,678
Foreign taxes withheld		(3,195,232	)
Total investment income		29,228,499
EXPENSES
Investment advisory		270,325
Accounting services		251,249
Professional		73,364
Pricing		72,532
Trustees		22,740
Printing		1,338
Miscellaneous		11,456
Total expenses		703,004
Less fees waived and/or reimbursed by the Manager		(4,972	)
Total expenses after fees waived and/or reimbursed		698,032
Net investment income		28,530,467
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Futures contracts		1,424,955
Foreign currency transactions		(64,780	)
Investments — affiliated		13,030
Investments — unaffiliated (including $6,808 foreign capital gain tax)		(6,340,051	)
		(4,966,846	)
Net change in unrealized appreciation (depreciation) on:
Futures contracts		127,831
Foreign currency translations		(6,982	)
Investments — affiliated		1,944
Investments — unaffiliated (including $(39,377) foreign capital gain tax)		149,488,336
		149,611,129
Net realized and unrealized gain		144,644,283
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	173,174,750

See notes to financial statements.

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	Total International ex U.S. Index Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	28,530,467		$	26,779,451
Net realized gain (loss)		(4,966,846	)		4,179,101
Net change in unrealized appreciation (depreciation)		149,611,129			(156,335,463	)
Net increase (decrease) in net assets resulting from operations		173,174,750			(125,376,911	)
CAPITAL TRANSACTIONS
Proceeds from contributions		533,180,584			439,538,961
Value of withdrawals		(371,145,212	)		(603,313,951	)
Net increase (decrease) in net assets derived from capital transactions		162,035,372			(163,774,990	)
NET ASSETS
Total increase (decrease) in net assets		335,210,122			(289,151,901	)
Beginning of year		759,697,395			1,048,849,296
End of year	$	1,094,907,517		$	759,697,395

See notes to financial statements.

FINANCIAL STATEMENTS 41

Financial Highlights

(For a share outstanding throughout each period)

	Total International ex U.S. Index Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		21.29	%		(13.87	)%		27.67	%		4.41	%		(5.80	)%
Ratios to Average Net Assets
Total expenses		0.08	%		0.08	%		0.07	%		0.08	%		0.08	%
Total expenses after fees waived and paid indirectly		0.08	%		0.08	%		0.07	%		0.08	%		0.07	%
Net investment income		3.17	%		2.87	%		2.85	%		2.90	%		2.71	%
Supplemental Data
Net assets, end of year (000)	$	1,094,908		$	759,697		$	1,048,849		$	1,000,386		$	836,637
Portfolio turnover rate		5	%		40	%		57	%		15	%		6	%

See notes to financial statements.

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. Total International ex U.S. Index Master Portfolio (the “Master Portfolio”) is a series of MIP. The Master Portfolio is classified as diversified.

The Master Portfolio, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income and non-cash dividend income are recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the Master Portfolio is informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain.

Foreign Currency Translation:The Master Portfolio’s books and records are maintained in U.S. dollars. Securities and other assets and liabilities denominated in foreign currencies are translated into U.S. dollars using exchange rates determined as of the close of trading on the New York Stock Exchange (“NYSE”). Purchases and sales of investments are recorded at the rates of exchange prevailing on the respective dates of such transactions. Generally, when the U.S. dollar rises in value against a foreign currency, the investments denominated in that currency will lose value; the opposite effect occurs if the U.S. dollar falls in relative value.

The Master Portfolio does not isolate the portion of the results of operations arising as a result of changes in the exchange rates from the changes in the market prices of investments held or sold for financial reporting purposes. Accordingly, the effects of changes in exchange rates on investments are not segregated in the Statement of Operations from the effects of changes in market prices of those investments, but are included as a component of net realized and unrealized gain (loss) from investments. The Master Portfolio reports realized currency gains (losses) on foreign currency related transactions as components of net realized gain (loss) for financial reporting purposes, whereas such components are generally treated as ordinary income for U.S. federal income tax purposes.

Segregation and Collateralization:In cases where the Master Portfolio enters into certain investments (e.g., futures contracts) that would be treated as “senior securities” for 1940 Act purposes, the Master Portfolio may segregate or designate on its books and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the Master Portfolio may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, the Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. The Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Master Portfolio, which cannot be predicted with any certainty.

Other:Expenses directly related to the Master Portfolio are charged to the Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the NYSE (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board of Trustees of MIP (the “Board”). The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of the Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

Generally, trading in foreign instruments is substantially completed each day at various times prior to the close of trading on the NYSE. Occasionally, events affecting the values of such instruments may occur between the foreign market close and the close of trading on the NYSE that may not be reflected in the

NOTESTO FINANCIAL STATEMENTS 43

Notes to Financial Statements  (continued)

computation of the Master Portfolio’s net assets. Each business day, the Master Portfolio uses a pricing service to assist with the valuation of certain foreign exchange-traded equity securities and foreign exchange-traded andover-the-counter (“OTC”) options (the “Systematic Fair Value Price”). Using current market factors, the Systematic Fair Value Price is designed to value such foreign securities and foreign options at fair value as of the close of trading on the NYSE, which follows the close of the local markets.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that the Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

For investments in equity or debt issued by privately held companies or funds (“Private Company” or collectively, the “Private Companies”) and other Fair Valued Investments, the fair valuation approaches that are used by the Global Valuation Committee and third party pricing services utilize one or a combination of, but not limited to, the following inputs.

Standard Inputs Generally Considered By Third Party Pricing Services
Market approach	(i)  recent market transactions, including subsequent rounds of financing, in the underlying investment or comparable issuers; (ii) recapitalizations and other transactions across the capital structure; and (iii)   market multiples of comparable issuers.
Income approach	(i)  future cash flows discounted to present and adjusted as appropriate for liquidity, credit, and/or market risks; (ii) quoted prices for similar investments or assets in active markets; and (iii)   other risk factors, such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks, recovery rates, liquidation amounts and/or default rates.
Cost approach	(i)  audited or unaudited financial statements, investor communications and financial or operational metrics issued by the Private Company; (ii) changes in the valuation of relevant indices or publicly traded companies comparable to the Private Company; (iii)   relevant news and other public sources; and (iv)   known secondary market transactions in the Private Company’s interests and merger or acquisition activity in companies comparable to the Private Company.

Investments in series of preferred stock issued by Private Companies are typically valued utilizing market approach in determining the enterprise value of the company. Such investments often contain rights and preferences that differ from other series of preferred and common stock of the same issuer. Valuation techniques such as an option pricing model (“OPM”), a probability weighted expected return model (“PWERM”) or a hybrid of those techniques are used in allocating enterprise value of the company, as deemed appropriate under the circumstances. The use of OPM and PWERM techniques involve a determination of the exit scenarios of the investment in order to appropriately allocate the enterprise value of the company among the various parts of its capital structure.

The Private Companies are not subject to the public company disclosure, timing, and reporting standards as other investments held by the Master Portfolio. Typically, the most recently available information by a Private Company is as of a date that is earlier than the date the Master Portfolio is calculating its NAV. This factor may result in a difference between the value of the investment and the price the Master Portfolio could receive upon the sale of the investment.

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Private Companies. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

4. SECURITIES AND OTHER INVESTMENTS

Preferred Stocks: Preferred stock has a preference over common stock in liquidation (and generally in receiving dividends as well), but is subordinated to the liabilities of the issuer in all respects. As a general rule, the market value of preferred stock with a fixed dividend rate and no conversion element varies inversely with interest rates and perceived credit risk, while the market price of convertible preferred stock generally also reflects some element of conversion value. Because preferred stock is junior to debt securities and other obligations of the issuer, deterioration in the credit quality of the issuer will cause greater changes in the value of a preferred stock than in a more senior debt security with similar stated yield characteristics. Unlike interest payments on debt securities, preferred stock dividends are payable only if declared by the issuer’s board of directors. Preferred stock also may be subject to optional or mandatory redemption provisions.

Warrants:Warrants entitle a fund to purchase a specified number of shares of common stock and are non-income producing. The purchase price and number of shares are subject to adjustment under certain conditions until the expiration date of the warrants, if any. If the price of the underlying stock does not rise above the strike price before the warrant expires, the warrant generally expires without any value and a fund will lose any amount it paid for the warrant. Thus, investments in warrants may involve more risk than investments in common stock. Warrants may trade in the same markets as their underlying stock; however, the price of the warrant does not necessarily move with the price of the underlying stock.

Securities Lending: The Master Portfolio may lend its securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the Master Portfolio collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by the Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the Master Portfolio and any additional required collateral is delivered to the Master Portfolio, or excess collateral returned by the Master Portfolio, on the next business day. During the term of the loan, the Master Portfolio is entitled to all distributions made on or in respect of the loaned securities, but does not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as common stocks in the Master Portfolio’s Schedule of Investments, and the value of any related collateral are shown separately in the Statement of Assets and Liabilities as a component of investments at value – unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedule of Investments.

Securities lending transactions are entered into by the Master Portfolio under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the Master Portfolio, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and the Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the Master Portfolio’s securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount (b)
Barclays Capital INC.	$	382,940	$	(382,940	)	$	—
BNP Paribas Prime Brokerage International Limited		137,827		(137,827	)		—
Citigroup Global Markets INC.		1,968,140		(1,968,140	)		—
Credit Suisse Securities (USA) LLC		880,308		(572,343	)		307,965
Goldman Sachs & Co.		1,680,828		(1,680,828	)		—
Jefferies LLC		110,418		(110,418	)		—
JP Morgan Securities LLC		994,902		(994,902	)		—
Morgan Stanley & Co LLC		8,253,044		(8,253,044	)		—
Morgan Stanley & Co. International PLC		61,320		(61,320	)		—
Morgan Stanley & Co. LLC (US Equity Sec Lending)		89,590		(89,590	)		—
National Financial Services LLC		150,672		(150,672	)		—
SG Americas Securities LLC		369,054		(369,054	)		—
State Street Bank & Trust Company		96,360		(96,360	)		—
TD Prime Services LLC		25,470		(25,470	)		—
UBS AG		56,941		(56,941	)		—
Wells Fargo Bank, National Association		765,188		(765,188	)		—
	$	16,023,002	$	(15,715,037	)	$	307,965

NOTESTO FINANCIAL STATEMENTS 45

Notes to Financial Statements  (continued)

(a) Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by the Master Portfolio is disclosed in the Master Portfolio’s Statement of Assets and Liabilities.

(b) The market value of the loaned securities is determined as of December 31, 2019. Additional collateral is delivered to the Master Portfolio on the next business day in accordance with the MSLA. The net amount would be subject to the borrower default indemnity in the event of default by the counterparty.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the Master Portfolio benefits from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”). BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. The Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the Master Portfolio.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The Master Portfolio engages in various portfolio investment strategies using derivative contracts both to increase the returns of the Master Portfolio and/or to manage its exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedule of Investments. These contracts may be transacted on an exchange or OTC.

Futures Contracts:Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

Futures contracts are agreements between the Master Portfolio and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the Master Portfolio is required to deposit initial margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statement of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedule of Investments and cash deposited, if any, are shown as cash pledged for futures contracts in the Statement of Assets and Liabilities. Pursuant to the contract, the Master Portfolio agrees to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statement of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statement of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the Master Portfolio, entered into an Investment Advisory Agreement with the Manager, the Master Portfolio’s investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of the Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Master Portfolio.

For such services, the Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.03% of the average daily value of the Master Portfolio’s net assets.

BAL is not entitled to compensation for providing administrative services to the Master Portfolio, for so long as BAL (or an affiliate) is entitled to compensation for providing administrative services to corresponding feeder funds that invest substantially all of their assets in the Master Portfolio, or BAL (or an affiliate) receives investment advisory fees from the Master Portfolio.

Expense Limitations, Waivers, Reimbursements and Recoupments: With respect to the Master Portfolio, the Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees the Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). The amount of waivers and/or reimbursements of fees and expenses made pursuant to the expense limitation described below will be reduced by the amount of the affiliated money market fund waiver. This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the amount waived and/or reimbursed was $4,972.

The Manager has contractually agreed to waive its investment advisory fee with respect to any portion of the Master Portfolio’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through April 30, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees, or by a vote of a majority of the outstanding voting securities of the Master Portfolio. For the year ended December 31, 2019, there were no fees waived and/or reimbursed by the Manager pursuant to this arrangement.

Securities Lending: The SEC has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The Master Portfolio is responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the Master Portfolio bears to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a90-day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, the Master Portfolio retains 82% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, the Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 85% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Statement of Operations. For the year ended December 31, 2019, the Master Portfolio paid BTC $58,631 for securities lending agent services.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, the Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Master Portfolio’s investment policies and restrictions. The Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33¹⁄₃% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Trustees and Officers: Certain trustees and/or officers of MIP are directors and/or officers of BlackRock or its affiliates.

Other Transactions: The Master Portfolio may purchase securities from, or sell securities to, an affiliated fund provided the affiliation is due solely to having a common investment adviser, common officers, or common trustees. For the year ended December 31, 2019, the purchase and sale transactions and any net realized gains (losses) with affiliated funds in compliance with Rule17a-7 under the 1940 Act were as follows:

Purchases		Sales		Net Realized Gain (Loss)
$	8,747,849	$	2,745,081	$	(246,438	)

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments, excluding short-term securities, were $226,166,288 and $41,275,023, respectively.

8. INCOME TAX INFORMATION

The Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

Tax cost	$	903,907,220
Gross unrealized appreciation	$	271,635,951
Gross unrealized depreciation		(64,870,591	)
Net unrealized appreciation	$	206,765,360

NOTESTO FINANCIAL STATEMENTS 47

Notes to Financial Statements  (continued)

9. BANK BORROWINGS

MIP, on behalf of the Master Portfolio, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the Master Portfolio may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the Master Portfolio, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statement of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the Master Portfolio did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, the Master Portfolio invests in securities or other instruments and may enter into certain transactions, and such activities subject the Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. The Master Portfolio’s prospectus provides details of the risks to which the Master Portfolio is subject.

The Master Portfolio may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk:The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. The Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that the Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. The Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause the Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of the Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which the Master Portfolio invests.

The price the Master Portfolio could receive upon the sale of any particular portfolio investment may differ from the Master Portfolio’s valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair valuation technique or a price provided by an independent pricing service. Changes to significant unobservable inputs and assumptions (i.e., publicly traded company multiples, growth rate, time to exit) due to the lack of observable inputs may significantly impact the resulting fair value and therefore the Master Portfolio’s results of operations. As a result, the price received upon the sale of an investment may be less than the value ascribed by the Master Portfolio, and the Master Portfolio could realize a greater than expected loss or lesser than expected gain upon the sale of the investment. The Master Portfolio’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third party service providers.

Counterparty Credit Risk:The Master Portfolio may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolio manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Master Portfolio to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolio’s exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Master Portfolio.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

With exchange-traded futures, there is less counterparty credit risk to the Master Portfolio since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, the Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Master Portfolio.

Concentration Risk:The Master Portfolio invests a significant portion of its assets in securities of issuers located in Europe or with significant exposure to European issuers or countries. The European financial markets have recently experienced volatility and adverse trends due to concerns about economic downturns in, or rising government debt levels of, several European countries. These events may spread to other countries in Europe and may affect the value and liquidity of certain of the Master Portfolio’s investments.

48 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Responses to the financial problems by European governments, central banks and others, including austerity measures and reforms, may not work, may result in social unrest and may limit future growth and economic recovery or have other unintended consequences. Further defaults or restructurings by governments and others of their debt could have additional adverse effects on economies, financial markets and asset valuations around the world. In addition, the United Kingdom has voted to withdraw from the European Union, and one or more other countries may withdraw from the European Union and/or abandon the Euro, the common currency of the European Union. The impact of these actions, especially if they occur in a disorderly fashion, is not clear but could be significant and far reaching.

The Master Portfolio invests a significant portion of its assets in securities of issuers located in Asia or with significant exposure to Asian issuers or countries. The Asian financial markets have recently experienced volatility and adverse trends due to concerns in several Asian countries regarding monetary policy, government intervention in the markets, rising government debt levels or economic downturns. These events may spread to other countries in Asia and may affect the value and liquidity of certain of the Master Portfolio’s investments.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolio through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 49

Report of Independent Registered Public Accounting Firm Total International ex U.S. Index Master Portfolio

To the Board of Trustees of

Master Investment Portfolio and Investors of Total International ex U.S. Index Master Portfolio

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Total International ex U.S. Index Master Portfolio (one of the series constituting Master Investment Portfolio, referred to hereafter as the “Master Portfolio”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Master Portfolio as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Master Portfolio’s management. Our responsibility is to express an opinion on the Master Portfolio’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolio in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

50 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of BlackRock Funds III and MIP, on behalf of iShares MSCI Total International Index Fund and Total International ex U.S. Index Master Portfolio, respectively, met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements: The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

STATEMENT REGARDING LIQUIDITY RISK MANAGEMENT PROGRAM 51

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

52 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

TRUSTEEAND OFFICER INFORMATION 53

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015); President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate.
(c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015.
(d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex.
(e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

54 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge by calling(800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Distributor

BlackRock Investments, LLC

New York, NY 10022

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

TRUSTEEAND OFFICER INFORMATION 55

Additional Information

General Information

Householding

The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Fund at(800) 441-7762.

Availability of Quarterly Schedule of Investments

The Fund/Master Portfolio file their complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information on Form N-Q. The Fund’s/Master Portfolio’s Forms N-PORT and N-Q are available on the SEC’s website at sec.gov. The Fund’s/Master Portfolio’s Forms N-Q may also be obtained upon request and without charge by calling (800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Fund/Master Portfolio uses to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling (800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Fund/Master Portfolio voted proxies relating to securities held in the Fund’s/Master Portfolio’s portfolio during the most recent 12-month period ended June 30 is available upon request and without charge (1) atblackrock.com; or by calling(800) 441-7762; and (2) on the SEC’s website at sec.gov.

BlackRock’s Mutual Fund Family

BlackRock offers a diverse lineup of open-end mutual funds crossing all investment styles and managed by experts in equity, fixed-income and tax-exempt investing. Visitblackrock.com for more information.

Shareholder Privileges

Account Information

Call us at (800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visitblackrock.com for more information.

Automatic Investment Plans

Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.

Systematic Withdrawal Plans

Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.

Retirement Plans

Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.

56 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information  (continued)

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding their non-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal non-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose to non-affiliated third parties any non-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. These non-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to non-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the non-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

Glossary of Terms Used in this Report

Portfolio Abbreviations
ADR	American Depositary Receipts
CVA	Certificaten Van Aandelen (Dutch Certificate)
GDR	Global Depositary Receipt
MSCI	Morgan Stanley Capital International
NVDR	Non-voting Depository Receipts
REIT	Real Estate Investment Trust
S&P	Standard & Poor’s

ADDITIONAL INFORMATION 57

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund’s current prospectus. Past performance results shown in this report should not be considered a representation of future performance. Investment returns and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Statements and other information herein are as dated and are subject to change.

TIEXUS-12/19-AR

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· iShares Russell 1000 Large-Cap Index Fund

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call(800) 441-7762 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: (i) accessing the BlackRock website at blackrock.com/edelivery and logging into your accounts, if you hold accounts directly with BlackRock, or (ii) contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summary		4
About Fund Performance		6
Disclosure of Expenses		6
Fund Financial Statements:
Statement of Assets and Liabilities		7
Statement of Operations		8
Statements of Changes in Net Assets		9
Fund Financial Highlights		10
Fund Notes to Financial Statements		13
Fund Report of Independent Registered Public Accounting Firm		17
Important Tax Information		17
Master Portfolio Information		18
Derivative Financial Instruments		18
Master Portfolio Financial Statements:
Schedule of Investments		19
Statement of Assets and Liabilities		30
Statement of Operations		31
Statements of Changes in Net Assets		32
Master Portfolio Financial Highlights		33
Master Portfolio Notes to Financial Statements		34
Master Portfolio Report of Independent Registered Public Accounting Firm		39
Statement Regarding Liquidity Risk Management Program		40
Trustee and Officer Information		41
Additional Information		45
Glossary of Terms Used in this Report		46

3

Fund Summary  as of December 31, 2019 iShares Russell 1000 Large-Cap Index Fund

Investment Objective

iShares Russell 1000 Large-Cap Index Fund’s (the “Fund”) investment objective is to match the performance of the Russell 1000^® Index as closely as possible before the deduction of Fund expenses.

Portfolio Management Commentary

How did the Fund perform?

For the12-month period ended December 31, 2019, the Fund’s Institutional Shares returned 31.28%, Investor A Shares returned 30.98%, and Class K Shares returned 31.28%. The benchmark Russell 1000^® Index returned 31.43% for the same period.

Returns for the Fund’s respective share classes differ from the benchmark index based on individual share-class expenses. The Fund invests all of its assets in Large Cap Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio.

Describe the market environment.

All eleven of the Global Industry Classification Standard sectors advanced in the first quarter of 2019 as positive headlines regarding Sino-American trade negotiations, relatively strong corporate earnings growth, and the Fed’s dovish pivot helped investor sentiment recover from steep losses in the fourth quarter of 2018. The technology sector outperformed with real estate the second best-performing sector as a decline in interest rates throughout the quarter drove demand for bond proxies. Health care shares underperformed as political risks weighed on sentiment, but still posted a respectable gain.

In its January 2019 announcement, the Fed indicated that it would refrain from interest rate hikes for the foreseeable future, with a dovish assessment of U.S. economic conditions and transparency around balance sheet normalization. This reduced market-based expectations of interest rate hikes, serving as a boon for both equities and bonds. Less optimism was evident in the U.S. rates market. The pause in interest rate hiking by the Fed coupled with lowered forecasts for growth drove investors into longer-duration government bonds.

The prospect of an easier monetary policy buoyed equities broadly in the second quarter of 2019. At the June Federal Open Market Committee announcement, Fed Chair Jerome Powell noted that should trade tensions weigh on the committee’s economic outlook or should the shortfall of inflation from the target rate persist longer than expected, the Fed would provide more accommodation to sustain the expansion.

Trade tensions were a source of intra-quarter volatility. In May, President Trump threatened an increase in tariffs and protectionism against both China and Mexico. However, these announcements did not materialize, and sentiment eased by June month end.

Looking to interest rates, the10-year U.S. Treasury yield declined 0.50% in the second quarter to 2% — the lowest level since 2016. The yield curve remained a source of uncertainty as thethree-month/10-year Treasury spread remained in negative territory while thefive-year/30-year Treasury spread expanded throughout the quarter.

In the third quarter of 2019, trade tensions were a key focus for both domestic and global investors. Markets suffered in early August on the back of President Trump’s promise to impose 10% tariffs on all Chinese imports that were not already subject to 25% tariffs. U.S.-China tensions did ostensibly ease ahead of a new round of trade talks in October. In monetary policy, the Fed lowered the target range for the federal funds rates at both its July and September meetings.

On the macroeconomic front, survey-based U.S. economic indicators continued to soften in the manufacturing and consumer sectors, while hard economic data releases exhibited resilience. In interest rates, the frequently monitoredtwo-year/ten-year Treasury yield spread inverted for the first time since the global financial crisis in August but ended the quarter in positive territory.

In the fourth quarter of 2019, risk appetite was boosted broadly by expectations of a U.S.-China trade deal, strong economic growth, and easy monetary policy. U.S. tariffs on China were originally scheduled to increase on December 15 but were avoided due to persistent negotiations between the United States and China. Additionally, news that the United States did not impose tariffs on European Union auto exports helped support sentiment. On the macroeconomic front, the U.S. services and employment sectors remained buoyant.

In November, 266,000 jobs were added to the economy, revising the third quarter unemployment rate down to 3.5% from 3.7%. Overall, the supportive macroeconomic data and boosted risk appetite drove selling of Treasuries in the quarter. Despite the strength in the U.S. economy, the Fed cut the benchmark federal funds rate to 1.75% in October, marking the third rate cut of the year.

Describe recent portfolio activity.

During the period, as changes were made to the composition of the Russell 1000^® Index, the Master Portfolio purchased and sold securities to maintain its objective of replicating the risks and return of the benchmark index.

Describe portfolio positioning at period end.

The Master Portfolio remains positioned to match the risk characteristics of its benchmark index, irrespective of the market’s future direction.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) iShares Russell 1000 Large-Cap Index Fund

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming transaction costs and other operating expenses, including administration fees, if any.

^(b)  The Fund invests all of its assets in the Master Portfolio. The Master Portfolio will be substantially invested in equity securities in the Russell 1000^® Index and will invest, under normal circumstances, at least 80% of its assets in securities or other financial instruments that are components of or have economic characteristics similar to the securities included in the Russell 1000^® Index.

^(c)  An index that measures the performance of the large-cap segment of the U.S. equity universe. It is a subset of the Russell 3000^® Index and includes approximately 1,000 of the largest securities based on a combination of their market capitalization and current index membership. The index represents approximately 92% of the total market capitalization of the Russell 3000^® Index.

^(d)  Commencement of operations.

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
	6-Month Total Returns			1 Year			5 Years			Since Inception (b)
Institutional		10.55	%		31.28	%		11.35	%		12.74	%
Investor A		10.37			30.98			11.06			12.41
Class K		10.51			31.28			11.39			12.74
Russell 1000® Index		10.59			31.43			11.48			12.88

^(a)  See “About Fund Performance” on Page 6 for a detailed description of share classes, including any related fees.

^(b)  The Fund commenced operations on March 31, 2011.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

Expense Example

	Actual						Hypothetical (b)
	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
Institutional	$	1,000.00	$	1,105.50	$	0.69	$	1,000.00	$	1,024.55	$	0.66		0.13	%
Investor A		1,000.00		1,103.70		2.01		1,000.00		1,023.29		1.94		0.38
Class K		1,000.00		1,105.10		0.42		1,000.00		1,024.80		0.41		0.08

^(a)  For each class of the Fund, expenses are equal to the annualized net expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period shown). Because the Fund invests all of its assets in the Master Portfolio, the expense example reflects the net expenses of both the Fund and the Master Portfolio in which it invests.

^(b)  Hypothetical 5% annual return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

See “Disclosure of Expenses” on page 6 for further information on how expenses were calculated.

FUND SUMMARY 5

About Fund Performance

Institutional and Class K Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors.

Investor A Shares are not subject to any sales charge and bear no ongoing distribution fee. These shares are subject to an ongoing service fee of 0.25% per year. These shares are generally available through financial intermediaries.

Performance information reflects past performance and does not guarantee future results. Current performance may be lower or higher than the performance data quoted. Refer toblackrock.com to obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Figures shown in the performance table on the previous page assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend date. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of service, distribution and transfer agency fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (the “Administrator”), the Fund’s administrator, has contractually and/or voluntarily agreed to waive and/or reimburse a portion of the Fund’s expenses. Without such waiver and/or reimbursement, the Fund’s performance would have been lower. With respect to the Fund’s voluntary waiver, the Administrator is under no obligation to waive and/or reimburse or to continue waiving and/or reimbursing its fees and such voluntary waiver may be reduced or discontinued at any time. With respect to the Fund’s contractual waiver, the Administrator is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See Note 4 of the Notes to Financial Statements for additional information on waivers and/or reimbursements.

Disclosure of Expenses

Shareholders of the Fund may incur the following charges: (a) transactional expenses; and (b) operating expenses, including administration fees, service and distribution fees, including12b-1 fees, acquired fund fees and expenses and other fund expenses. The expense example on the previous page (which is based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019) is intended to assist shareholders both in calculating expenses based on an investment in the Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense example provides information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their share class under the heading entitled “Expenses Paid During the Period.”

The expense example also provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in the Fund and other funds, compare the 5% hypothetical example with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense example are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical example is useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	iShares Russell 1000 Large-Cap Index Fund
ASSETS
Investments at value — Master Portfolio	$	456,334,199
Receivables:
Capital shares sold		12,182,488
From the Administrator/Manager		6,912
Prepaid expenses		21,755
Total assets		468,545,354
LIABILITIES
Payables:
Administration fees		6,577
Capital shares redeemed		1,886,587
Contributions to the Master		10,295,901
Other accrued expenses		77,156
Service fees		17,889
Recoupment of past waived fees		2,271
Total liabilities		12,286,381
NET ASSETS	$	456,258,973
NET ASSETS CONSIST OF
Paid-in capital	$	316,458,385
Accumulated earnings		139,800,588
NET ASSETS	$	456,258,973
NET ASSET VALUE
Institutional — Based on net assets of $82,728,774 and 3,914,097 shares outstanding, unlimited number of shares authorized, no par value	$	21.14
Investor A — Based on net assets of $86,038,155 and 4,095,559 shares outstanding, unlimited number of shares authorized, no par value	$	21.01
ClassK — Based on net assets of $287,492,044 and 13,656,200 shares outstanding, unlimited number of shares authorized, no par value	$	21.05

See notes to financial statements.

FINANCIAL STATEMENTS 7

Statement of Operations

Year Ended December 31, 2019

	iShares Russell 1000 Large-Cap Index Fund
INVESTMENT INCOME
Net investment income allocated from the Master Portfolio:
Dividends — unaffiliated	$	6,529,980
Dividends — affiliated		157,887
Securities lending income — affiliated — net		118,113
Foreign taxes withheld		(525	)
Expenses		(117,369	)
Fees waived		3,170
Total investment income		6,691,256
FUND EXPENSES
Transfer agent — class specific		341,727
Service — class specific		175,510
Professional		65,683
Registration		63,628
Administration		34,970
Printing		23,638
Recoupment of past waived and/or reimbursed fees — class specific		7,827
Accounting services		5,088
Officer		148
Miscellaneous		8,774
Total expenses		726,993
Less:
Fees waived and/or reimbursed by the Administrator/ Manager		(36,766	)
Transfer agent fees waived and/or reimbursed — class specific		(274,819	)
Total expenses after fees waived and/or reimbursed		415,408
Net investment income		6,275,848
REALIZED AND UNREALIZED GAIN (LOSS) ALLOCATED FROM THE MASTER PORTFOLIO
Net realized gain (loss) from:
Futures contracts		1,000,435
Investments — affiliated		(241,064	)
Investments — unaffiliated		1,632,746
		2,392,117
Net change in unrealized appreciation (depreciation) on:
Futures contracts		1,395
Investments — affiliated		487,292
Investments — unaffiliated		86,143,282
		86,631,969
Net realized and unrealized gain		89,024,086
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	95,299,934

See notes to financial statements.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	iShares Russell 1000 Large-Cap Index Fund
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	6,275,848		$	4,644,783
Net realized gain		2,392,117			1,210,484
Net change in unrealized appreciation (depreciation)		86,631,969			(23,156,898	)
Net increase (decrease) in net assets resulting from operations		95,299,934			(17,301,631	)
DISTRIBUTIONS TO SHAREHOLDERS(a)
Institutional		(2,269,109	)		(1,332,772	)
Investor A		(2,032,385	)		(1,251,128	)
Class K		(6,315,002	)		(3,120,575	)
Decrease in net assets resulting from distributions to shareholders		(10,616,496	)		(5,704,475	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		57,699,811			125,324,876
NET ASSETS
Total increase in net assets		142,383,249			102,318,770
Beginning of year		313,875,724			211,556,954
End of year	$	456,258,973		$	313,875,724

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 9

Financial Highlights

(For a share outstanding throughout each period)

	iShares Russell 1000Large-Cap Index Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	16.58		$	17.82		$	15.07		$	14.08		$	14.72
Net investment income(a)		0.35			0.34			0.30			0.31			0.28
Net realized and unrealized gain (loss)		4.79			(1.19	)		2.91			1.35			(0.16	)
Net increase (decrease) from investment operations		5.14			(0.85	)		3.21			1.66			0.12
Distributions(b)
From net investment income		(0.39	)		(0.33	)		(0.35	)		(0.29	)		(0.29	)
From net realized gain		(0.19	)		(0.06	)		(0.11	)		(0.38	)		(0.47	)
From return of capital		—			—			(0.00	)(c)		—			—
Total distributions		(0.58	)		(0.39	)		(0.46	)		(0.67	)		(0.76	)
Net asset value, end of year	$	21.14		$	16.58		$	17.82		$	15.07		$	14.08
Total Return(d)
Based on net asset value		31.28	%		(4.88	)%		21.46	%		11.92	%		0.82	%
Ratios to Average Net Assets(e)
Total expenses		0.15	%(f)(g)		0.17	%(f)(h)		0.17	%(f)(h)		0.13	%(f)		0.27	%(i)
Total expenses after fees waived and/or reimbursed		0.13	%(f)		0.13	%(f)		0.13	%(f)		0.09	%(f)		0.13	%(i)
Net investment income		1.81	%(f)		1.89	%(f)		1.82	%(f)		2.14	%(f)		1.93	%(i)
Supplemental Data
Net assets, end of year (000)	$	82,729		$	102,279		$	45,733		$	18,964		$	3,431
Portfolio turnover rate of the Master Portfolio		10	%		12	%		12	%		13	%		6	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(g)  Includes recoupment of past waived and/or reimbursed fees. Excluding the recoupment of past waived and/or reimbursed fees for the year ended December, 31, 2019 the expense ratio would have been 0.14%.

^(h)  Includes recoupment of past waived and/or reimbursed fees with no financial impact to the expense ratios.

⁽ⁱ⁾  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares Russell 1000Large-Cap Index Fund
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	16.48		$	17.72		$	14.99		$	14.01		$	14.65
Net investment income(a)		0.30			0.29			0.26			0.25			0.24
Net realized and unrealized gain (loss)		4.76			(1.18	)		2.89			1.36			(0.16	)
Net increase (decrease) from investment operations		5.06			(0.89	)		3.15			1.61			0.08
Distributions(b)
From net investment income		(0.34	)		(0.29	)		(0.31	)		(0.25	)		(0.25	)
From net realized gain		(0.19	)		(0.06	)		(0.11	)		(0.38	)		(0.47	)
From return of capital		—			—			(0.00	)(c)		—			—
Total distributions		(0.53	)		(0.35	)		(0.42	)		(0.63	)		(0.72	)
Net asset value, end of year	$	21.01		$	16.48		$	17.72		$	14.99		$	14.01
Total Return(d)
Based on net asset value		30.98	%		(5.15	)%		21.16	%		11.61	%		0.56	%
Ratios to Average Net Assets(e)
Total expenses		0.76	%(f)		0.87	%(f)		0.68	%(f)(g)		0.48	%(f)		0.54	%(h)
Total expenses after fees waived and/or reimbursed		0.38	%(f)		0.38	%(f)		0.38	%(f)		0.38	%(f)		0.39	%(h)
Net investment income		1.57	%(f)		1.60	%(f)		1.56	%(f)		1.76	%(f)		1.62	%(h)
Supplemental Data
Net assets, end of year (000)	$	86,038		$	57,500		$	66,675		$	23,939		$	17,397
Portfolio turnover rate of the Master Portfolio		10	%		12	%		12	%		13	%		6	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(g)  Includes recoupment of past waived and/or reimbursed fees. Excluding the recoupment of past waived and/or reimbursed fees for the year ended December, 31, 2017 the expense ratio would have been 0.67%.

^(h)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 11

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares Russell 1000Large-Cap Index Fund
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	16.52		$	17.76		$	15.01		$	14.03		$	14.67
Net investment income(a)		0.36			0.35			0.31			0.30			0.28
Net realized and unrealized gain (loss)		4.76			(1.19	)		2.91			1.36			(0.15	)
Net increase (decrease) from investment operations		5.12			(0.84	)		3.22			1.66			0.13
Distributions(b)
From net investment income		(0.40	)		(0.34	)		(0.36	)		(0.30	)		(0.30	)
From net realized gain		(0.19	)		(0.06	)		(0.11	)		(0.38	)		(0.47	)
From return of capital		—			—			(0.00	)(c)		—			—
Total distributions		(0.59	)		(0.40	)		(0.47	)		(0.68	)		(0.77	)
Net asset value, end of year	$	21.05		$	16.52		$	17.76		$	15.01		$	14.03
Total Return(d)
Based on net asset value		31.28	%		(4.85	)%		21.60	%		11.92	%		0.86	%
Ratios to Average Net Assets(e)
Total expenses		0.10	%(f)		0.13	%(f)		0.10	%(f)(g)		0.12	%(f)		0.19	%(h)
Total expenses after fees waived and/or reimbursed		0.08	%(f)		0.08	%(f)		0.08	%(f)		0.08	%(f)		0.09	%(h)
Net investment income		1.87	%(f)		1.92	%(f)		1.87	%(f)		2.06	%(f)		1.91	%(h)
Supplemental Data
Net assets, end of year (000)	$	287,492		$	154,097		$	99,149		$	122,724		$	77,632
Portfolio turnover rate of the Master Portfolio		10	%		12	%		12	%		13	%		6	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(g)  Includes recoupment of past waived and/or reimbursed fees with no financial impact to the expense ratio.

^(h)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. iShares Russell 1000Large-Cap Index Fund (the “Fund”) is a series of the Trust. The Fund is classified as diversified. The Fund seeks to achieve its investment objective by investing all of its assets in Large Cap Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio (“MIP”), an affiliate of the Trust, which has the same investment objective and strategies as the Fund. The value of the Fund’s investment in the Master Portfolio reflects the Fund’s proportionate interest in the net assets of the Master Portfolio. The performance of the Fund is directly affected by the performance of the Master Portfolio. At December 31, 2019, the percentage of the Master Portfolio owned by the Fund was 3.01%. The financial statements of the Master Portfolio, including the Schedule of Investments, are included elsewhere in this report and should be read in conjunction with the Fund’s financial statements.

The Fund offers multiple classes of shares. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that certain classes bear expenses related to the shareholder servicing and distribution of such shares. Institutional and Class K Shares are sold only to certain eligible investors. Investor A Shares bear certain expenses related to shareholder servicing of such shares. Investor A Shares are generally available through financial intermediaries. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures.

Share Class	Initial Sales Charge	CDSC		Conversion Privilege
Institutional Shares, Investor A and Class K	No		No	None

The Board of Trustees of the Trust and Board of Trustees of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

The Fund, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from the Master Portfolio are accounted for on a trade date basis. The Fund records its proportionate share of the Master Portfolio’s income, expenses and realized and unrealized gains and losses on a daily basis. Realized and unrealized gains and losses are adjusted utilizing partnership tax allocation rules. In addition, the Fund accrues its own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions paid by the Fund are recorded on theex-dividend date. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

Indemnifications:In the normal course of business, the Fund enters into contracts that contain a variety of representations that provide general indemnification. The Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to the Fund or its classes are charged to the Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by BlackRock Advisors, LLC (“BAL” or the “Administrator”), are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the Fund and other shared expenses prorated to the Fund are allocated daily to each class based on its relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Fund’s policy is to value its financial instruments at fair value. The Fund records its investment in the Master Portfolio at fair value based on the Fund’s proportionate interest in the net assets of the Master Portfolio. Valuation of securities held by the Master Portfolio is discussed in Note 3 of the Master Portfolio’s Notes to Financial Statements, which are included elsewhere in this report.

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration:The Trust, on behalf of the Fund, entered into an Administration Agreement with the Administrator, an indirect, wholly-owned subsidiary of BlackRock, Inc. (“BlackRock”), to provide administrative services (other than investment advice and related portfolio activities). For such services, the Fund pays the Administrator a monthly fee at an annual rate of 0.01% of the average daily net assets of the Fund. The Fund does not pay an investment advisory fee or investment management fee.

Service Fees: The Trust, on behalf of the Fund, entered into a Distribution Agreement and a Distribution and Service Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Pursuant to the Distribution and Service Plan and in accordance with Rule12b-1 under the 1940 Act, the Fund pays BRIL ongoing service fees. The fees are accrued daily and paid monthly at an annual rate of 0.25% based upon the average daily net assets of the Investor A Shares.

NOTESTO FINANCIAL STATEMENTS 13

Notes to Financial Statements  (continued)

BRIL and broker-dealers, pursuant tosub-agreements with BRIL, provide shareholder servicing services to the Fund. The ongoing service fee compensates BRIL and each broker-dealer for providing shareholder servicing related services to shareholders.

For the year ended December 31, 2019, the class specific service fees borne directly by Investor A Shares was $175,510.

Transfer Agent:Pursuant to written agreements, certain financial intermediaries, some of which may be affiliates, provide the Fund withsub-accounting, recordkeeping,sub-transfer agency and other administrative services with respect to servicing of underlying investor accounts. For these services, these entities receive an asset-based fee or an annual fee per shareholder account, which will vary depending on share class and/or net assets. For the year ended December 31, 2019, the Fund did not pay any amounts to affiliates in return for these services.

The Administrator maintains a call center that is responsible for providing certain shareholder services to the Fund. Shareholder services include responding to inquiries and processing purchases and sales based upon instructions from shareholders. For the year ended December 31, 2019, the Fund reimbursed the Administrator the following amounts for costs incurred in running the call center, which are included in transfer agent — class specific in the Statement of Operations:

Institutional		Investor A		Class K		Total
$	359	$	13,570	$	901	$	14,830

For the year ended December 31, 2019, the following table shows the class specific transfer agent fees borne directly by each share class of the Fund:

Institutional		Investor A		Class K		Total
$	36,993	$	292,201	$	12,533	$	341,727

Expense Limitations, Waivers, Reimbursements and Recoupments: BAL and BFA contractually agreed to waive and/or reimburse fees or expenses in order to limit expenses, excluding interest expense, dividend expense, tax expense, acquired fund fees and expenses, and certain other fund expenses, which constitute extraordinary expenses not incurred in the ordinary course of the Fund’s business (“expense limitation”). The expense limitations as a percentage of average daily net assets are as follows:

Institutional		Investor A		Class K
	0.13%		0.38%		0.08%

The Administrator/Manager has agreed not to reduce or discontinue these contractual expense limitations through April 30, 2020, unless approved by the Board, including a majority of the trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”) or by a vote of a majority of the outstanding voting securities of the Fund. For the year ended December 31, 2019, the Administrator/Manager waived and/or reimbursed $36,766, which is included in fees waived and/or reimbursed by the Administrator/Manager in the Statement of Operations.

These amounts waived and/or reimbursed are included in fees waived and/or reimbursed by the Administrator and transfer agent fees waived and/or reimbursed — class specific, respectively, in the Statement of Operations. For the year ended December 31, 2019, class specific transfer agent fees waived are as follows:

Institutional		Investor A		Class K		Total
$	5,372	$	257,013	$	12,434	$	274,819

With respect to the contractual expense limitation, if during the Fund’s fiscal year the operating expenses of a share class, that at any time during the prior two fiscal years received a waiver and/or reimbursement from BAL or BFA, are less than the current expense limitation for that share class, BAL and/or BFA is entitled to be reimbursed by such share class up to the lesser of: (a) the amount of fees waived and/or expenses reimbursed during those prior two fiscal years under the agreement and (b) an amount not to exceed either the current expense limitation of that share class or the expense limitation of the share class in effect at the time that the share class received the applicable waiver and/or reimbursement, provided that:

(1) The Fund, of which the share class is a part, has more than $50 million in assets for the fiscal year, and

(2) BAL, BFA or an affiliate continues to serve as the Fund’s investment adviser or administrator.

This repayment applies only to the contractual expense limitation on net expenses and does not apply to any voluntary waivers that may be in effect from time to time. Effective December 1, 2019, the repayment arrangement between the Fund and the BFA and/or BAL pursuant to which such Fund may be required to repay amounts waived and/or reimbursed under the Fund’s contractual caps on net expenses was terminated.

For the year ended December 31, 2019, BAL recouped the following fund level and class specific waivers and/or reimbursements previously recorded by the Fund:

Institutional		Investor A		Class K
$	7,827	$	—	$	—

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

The following fund level and class specific waivers and/or reimbursements previously recorded by the Fund, which were subject to recoupment by the Administrator, expired on December 1, 2019:

Fund Level	$	130,759
Institutional		4,905
Investor A		672,592
Class K		22,450

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), the Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Fund’s investment policies and restrictions. The Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Fund did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock or its affiliates. The Fund reimburses the Administrator for a portion of the compensation paid to the Trust’s Chief Compliance Officer, which is included in Trustees and Officers in the Master Portfolio’s Statement of Operations.

5. INCOME TAX INFORMATION

It is the Fund’s policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

The Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Fund as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Fund’s financial statements.

The tax character of distributions paid was as follows:

	12/31/19		12/31/18
Ordinary income	$	8,247,420	$	5,417,827
Long-term capital gains		2,369,076		286,648
	$	10,616,496	$	5,704,475

As of period end, the tax components of accumulated net earnings were as follows:

Undistributed ordinary income	$	501,667
Undistributed long-term capital gains		301,325
Net unrealized gains (losses)(a)		138,997,596
	$	139,800,588

^(a)  The differences between book-basis andtax-basis net unrealized gains (losses) was attributable primarily to the timing and recognition of partnership income.

NOTESTO FINANCIAL STATEMENTS 15

Notes to Financial Statements  (continued)

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended 12/31/19						Year Ended 12/31/18
	Shares			Amount			Shares			Amount
Institutional
Shares sold		835,213		$	16,242,478			5,051,507		$	88,693,979
Shares issued in reinvestment of distributions		114,292			2,268,551			74,900			1,331,969
Shares redeemed		(3,204,338	)		(59,262,954	)		(1,523,221	)		(26,923,935	)
Net increase (decrease)		(2,254,833	)	$	(40,751,925	)		3,603,186		$	63,102,013
Investor A
Shares sold		2,162,888		$	41,459,170			1,705,626		$	30,961,424
Shares issued in reinvestment of distributions		102,558			2,032,024			70,288			1,251,040
Shares redeemed		(1,658,112	)		(31,775,082	)		(2,049,828	)		(37,625,741	)
Net increase (decrease)		607,334		$	11,716,112			(273,914	)	$	(5,413,277	)
Class K
Shares sold		7,134,662		$	141,511,748			5,439,208		$	98,354,555
Shares issued in reinvestment of distributions		302,081			5,980,524			170,696			3,044,531
Shares redeemed		(3,110,790	)		(60,756,648	)		(1,863,036	)		(33,762,946	)
Net increase		4,325,953		$	86,735,624			3,746,868		$	67,636,140
Total Net Increase		2,678,454		$	57,699,811			7,076,140		$	125,324,876

7. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Fund through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm iShares Russell 1000 Large-Cap Index Fund

To the Board of Trustees of

BlackRock Funds III and Shareholders of iShares Russell 1000 Large-Cap Index Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of iShares Russell 1000 Large-Cap Index Fund (one of the series constituting BlackRock Funds III, referred to hereafter as the “Fund”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolio. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

Important Tax Information  (unaudited)

During the fiscal year ended December 31, 2019, the following information is provided with respect to the ordinary income distributions paid by the Fund:

	January – December 2019
Qualified Dividend Income for Individuals(a)	73.31%
Qualified Business Income(a)	4.92
Dividends Qualifying for the Dividend Received Deductions for Corporations(a)	70.52
Interest-Related Dividends and Qualified Short-Term Capital Gains for Non-U.S. Residents(b)	15.72

^(a)  The Fund hereby designates the percentage indicated above or the maximum amount allowable by law.

^(b)  Represents the portion of the taxable ordinary income dividends eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations.

Additionally, the Fund distributed long-term capital gains of 0.061932 per share and 0.066149 per share to shareholders of record on June 27, 2019 and December 11, 2019, respectively.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM / IMPORTANT TAX INFORMATION 17

Master Portfolio Information  as of December 31, 2019 Large Cap Index Master Portfolio

TEN LARGEST HOLDINGS

Security	Percent of Net Assets
Apple, Inc.		4	%
Microsoft Corp.		4
Alphabet, Inc.		3
Amazon.com, Inc.		3
Facebook, Inc.		2
Berkshire Hathaway, Inc.		1
JPMorgan Chase & Co.		1
Johnson & Johnson		1
Visa, Inc.		1
Procter & Gamble Co.		1

SECTOR ALLOCATION

Sector	Percent of Net Assets
Information Technology		22	%
Health Care		14
Financials		13
Short-Term Securities		11
Consumer Discretionary		10
Communication Services		10
Industrials		9
Consumer Staples		6
Energy		4
Real Estate		4
Utilities		3
Materials		3
Investment Companies		—	(a)
Liabilities in Excess of Other Assets		(9	)

^(a)  Represents less than 1% of Net Assets.

For Master Portfolio compliance purposes, the Master Portfolio’s sector classifications refer to one or more of the sector sub-classifications used by one or more widely recognized market indexes or ratings group indexes, and/or as defined by the investment adviser. These definitions may not apply for purposes of this report, which may combine such sector sub-classifications for reporting ease.

Derivative Financial Instruments

The Master Portfolio may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The Master Portfolio’s successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation the Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The Master Portfolio’s investments in these instruments, if any, are discussed in detail in the Master Portfolio’s Notes to Financial Statements.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Common Stocks — 97.8%
Aerospace & Defense — 2.3%
Arconic, Inc.		192,490	$	5,922,917
Boeing Co.		263,980		85,994,125
Curtiss-Wright Corp.(a)		20,691		2,915,155
General Dynamics Corp.		126,670		22,338,255
HEICO Corp.(a)		19,708		2,249,668
HEICO Corp., Class A		38,142		3,414,853
Hexcel Corp.(a)		42,866		3,142,507
Huntington Ingalls Industries, Inc.(a)		19,707		4,944,092
L3Harris Technologies, Inc.(a)		109,735		21,713,264
Lockheed Martin Corp.(a)		123,614		48,132,819
Northrop Grumman Corp.		78,616		27,041,546
Raytheon Co.		138,941		30,530,895
Spirit AeroSystems Holdings, Inc., Class A		50,972		3,714,839
Teledyne Technologies, Inc.(a)(b)		17,683		6,127,867
Textron, Inc.		114,868		5,123,113
TransDigm Group, Inc.(a)		24,497		13,718,320
United Technologies Corp.		404,934		60,642,916
				347,667,151
Air Freight & Logistics — 0.5%
C.H. Robinson Worldwide, Inc.(a)		66,034		5,163,859
Expeditors International of Washington, Inc.		84,750		6,612,195
FedEx Corp.(a)		120,446		18,212,640
United Parcel Service, Inc., Class B		349,393		40,899,944
XPO Logistics, Inc.(a)(b)		45,967		3,663,570
				74,552,208
Airlines — 0.4%
Alaska Air Group, Inc.(a)		59,973		4,063,171
American Airlines Group, Inc.(a)		191,606		5,495,260
Copa Holdings SA, Class A(a)		16,783		1,813,907
Delta Air Lines, Inc.		288,918		16,895,924
JetBlue Airways Corp.(b)		145,335		2,720,671
Southwest Airlines Co.		235,655		12,720,657
United Airlines Holdings, Inc.(b)		116,488		10,261,428
				53,971,018
Auto Components — 0.2%
Aptiv PLC(a)		127,762		12,133,557
BorgWarner, Inc.(a)		102,606		4,451,048
Gentex Corp.(a)		122,538		3,551,151
Goodyear Tire & Rubber Co.(a)		118,824		1,848,307
Lear Corp.(a)		31,102		4,267,195
				26,251,258
Automobiles — 0.5%
Ford Motor Co.(a)		1,957,454		18,204,322
General Motors Co.		616,887		22,578,064
Harley-Davidson, Inc.(a)		75,324		2,801,300
Tesla, Inc.(a)(b)		70,895		29,657,505
Thor Industries, Inc.(a)		27,643		2,053,599
				75,294,790
Banks — 5.4%
Associated Banc-Corp		73,078		1,610,639
Bank of America Corp.(a)		4,058,771		142,949,915
Bank of Hawaii Corp.(a)		18,581		1,768,168
Bank OZK(a)		57,786		1,762,762
BankUnited, Inc.		50,616		1,850,521
BOK Financial Corp.(a)		15,956		1,394,554
CIT Group, Inc.(a)		50,610		2,309,334
Citigroup, Inc.		1,088,375		86,950,279
Citizens Financial Group, Inc.		219,674		8,920,961
Comerica, Inc.(a)		71,982		5,164,708
Commerce Bancshares, Inc.(a)		49,429		3,358,206

Security	Shares		Value
Banks (continued)
Cullen/Frost Bankers, Inc.(a)		28,357	$	2,772,747
East West Bancorp, Inc.(a)		71,292		3,471,920
Fifth Third Bancorp		351,858		10,816,115
First Citizens BancShares, Inc., Class A		3,311		1,762,147
First Hawaiian, Inc.(a)		68,030		1,962,666
First Horizon National Corp.		155,035		2,567,380
First Republic Bank		83,788		9,840,901
FNB Corp.		164,449		2,088,502
Huntington Bancshares, Inc.(a)		517,258		7,800,251
JPMorgan Chase & Co.		1,555,421		216,825,687
KeyCorp		488,177		9,880,702
M&T Bank Corp.(a)		65,237		11,073,981
PacWest Bancorp(a)		60,351		2,309,633
People’s United Financial, Inc.(a)		218,199		3,687,563
Pinnacle Financial Partners, Inc.(a)		35,816		2,292,224
PNC Financial Services Group, Inc.		218,214		34,833,501
Popular, Inc.		48,885		2,871,994
Prosperity Bancshares, Inc.(a)		45,146		3,245,546
Regions Financial Corp.		480,167		8,239,666
Signature Bank		26,656		3,641,476
Sterling Bancorp		96,029		2,024,291
SVB Financial Group(a)(b)		26,056		6,541,098
Synovus Financial Corp.		66,409		2,603,233
TCF Financial Corp.(a)		72,846		3,409,193
Texas Capital Bancshares, Inc.(b)		22,922		1,301,282
Truist Financial Corp.(a)		670,004		37,734,625
U.S. Bancorp(a)		715,638		42,430,177
Umpqua Holdings Corp.(a)		109,831		1,944,009
Webster Financial Corp.		45,042		2,403,441
Wells Fargo & Co.(a)		1,900,742		102,259,920
Western Alliance Bancorp(a)		49,758		2,836,206
Wintrust Financial Corp.		30,232		2,143,449
Zions Bancorp. NA		85,292		4,428,361
				812,083,934
Beverages — 1.6%
Brown-Forman Corp., Class A(a)		22,750		1,428,018
Brown-Forman Corp., Class B(a)		84,118		5,686,377
Coca-Cola Co.(a)		1,911,989		105,828,591
Constellation Brands, Inc., Class A		78,627		14,919,473
Keurig Dr Pepper, Inc.		103,659		3,000,928
Molson Coors Brewing Co., Class B(a)		84,986		4,580,745
Monster Beverage Corp.(b)		191,979		12,200,266
PepsiCo, Inc.		698,620		95,480,395
				243,124,793
Biotechnology — 2.1%
AbbVie, Inc.(a)		738,034		65,345,530
Agios Pharmaceuticals, Inc.(a)(b)		31,302		1,494,671
Alexion Pharmaceuticals, Inc.(b)		107,077		11,580,378
Alkermes PLC(b)		84,964		1,733,266
Alnylam Pharmaceuticals, Inc.(a)(b)		53,583		6,171,154
Amgen, Inc.(a)		299,118		72,108,376
Biogen, Inc.(b)		89,750		26,631,518
BioMarin Pharmaceutical, Inc.(b)		87,388		7,388,655
Bluebird Bio, Inc.(a)(b)		28,635		2,512,721
Exact Sciences Corp.(a)(b)		69,271		6,406,182
Exelixis, Inc.(a)(b)		155,720		2,743,786
Gilead Sciences, Inc.		638,149		41,466,922
Incyte Corp.(b)		89,140		7,783,705
Ionis Pharmaceuticals, Inc.(b)		65,405		3,951,116
Moderna, Inc.(a)(b)		97,200		1,901,232
Neurocrine Biosciences, Inc.(b)		45,041		4,841,457
Regeneron Pharmaceuticals, Inc.(b)		40,533		15,219,331
Sage Therapeutics, Inc.(a)(b)		25,531		1,843,083

SCHEDULE OF INVESTMENTS 19

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Biotechnology (continued)
Sarepta Therapeutics, Inc.(a)(b)		35,811	$	4,621,051
Seattle Genetics, Inc.(a)(b)		57,439		6,562,980
United Therapeutics Corp.(b)		21,009		1,850,473
Vertex Pharmaceuticals, Inc.(b)		128,489		28,132,667
				322,290,254
Building Products — 0.3%
Allegion PLC		45,423		5,656,980
AO Smith Corp.(a)		66,918		3,187,974
Armstrong World Industries, Inc.		24,670		2,318,240
Fortune Brands Home & Security, Inc.(a)		67,809		4,430,640
Johnson Controls International PLC(a)		384,875		15,668,261
Lennox International, Inc.(a)		17,449		4,257,033
Masco Corp.(a)		144,087		6,914,735
Owens Corning(a)		53,684		3,495,902
Resideo Technologies, Inc.(b)		57,907		690,830
				46,620,595
Capital Markets — 2.5%
Affiliated Managers Group, Inc.(a)		23,180		1,964,273
Ameriprise Financial, Inc.(a)		63,044		10,501,870
Bank of New York Mellon Corp.		408,939		20,581,900
BGC Partners, Inc., Class A(a)		151,735		901,306
BlackRock, Inc.(a)(e)		58,828		29,572,836
Cboe Global Markets, Inc.		55,368		6,644,160
Charles Schwab Corp.(a)		572,841		27,244,318
CME Group, Inc.		177,314		35,590,466
E*Trade Financial Corp.		112,190		5,090,060
Eaton Vance Corp.(a)		52,909		2,470,321
Evercore, Inc., Class A		18,456		1,379,771
Franklin Resources, Inc.(a)		139,934		3,635,485
Goldman Sachs Group, Inc.(a)		158,853		36,525,070
Intercontinental Exchange, Inc.		273,105		25,275,868
Invesco Ltd.(a)		191,292		3,439,430
Janus Henderson Group PLC(a)		77,789		1,901,941
Lazard Ltd., Class A		51,262		2,048,430
Legg Mason, Inc.(a)		47,205		1,695,132
LPL Financial Holdings, Inc.		39,983		3,688,432
MarketAxess Holdings, Inc.		18,357		6,959,322
Moody’s Corp.(a)		82,104		19,492,311
Morgan Stanley		580,286		29,664,220
MSCI, Inc.		41,034		10,594,158
Nasdaq, Inc.(a)		56,674		6,069,785
Northern Trust Corp.(a)		96,438		10,245,573
Raymond James Financial, Inc.(a)		62,474		5,588,924
S&P Global, Inc.(a)		122,190		33,363,979
SEI Investments Co.(a)		65,143		4,265,564
State Street Corp.		180,823		14,303,099
T. Rowe Price Group, Inc.(a)		114,279		13,923,753
TD Ameritrade Holding Corp.		132,001		6,560,450
Virtu Financial, Inc., Class A(a)		27,179		434,592
				381,616,799
Chemicals — 1.9%
Air Products & Chemicals, Inc.		109,285		25,680,882
Albemarle Corp.(a)		51,954		3,794,720
Ashland Global Holdings, Inc.(a)		29,670		2,270,645
Axalta Coating Systems Ltd.(b)		102,122		3,104,509
Cabot Corp.		30,544		1,451,451
Celanese Corp.(a)		59,619		7,340,291
CF Industries Holdings, Inc.		111,351		5,315,897
Chemours Co.(a)		88,178		1,595,140
Corteva, Inc.(a)(b)		379,284		11,211,635
Dow, Inc.(b)		373,915		20,464,368
DuPont de Nemours, Inc.		367,860		23,616,612
Eastman Chemical Co.		68,468		5,426,774

Security	Shares		Value
Chemicals (continued)
Ecolab, Inc.(a)		125,222	$	24,166,594
Element Solutions, Inc.(b)		111,683		1,304,457
FMC Corp.(a)		63,810		6,369,514
Huntsman Corp.		104,039		2,513,582
International Flavors & Fragrances, Inc.(a)		53,449		6,895,990
Linde PLC(a)		267,856		57,026,542
LyondellBasell Industries NV, Class A(a)		134,016		12,661,832
Mosaic Co.(a)		175,070		3,788,515
NewMarket Corp.		3,234		1,573,406
Olin Corp.(a)		87,061		1,501,802
PPG Industries, Inc.		116,930		15,608,986
RPM International, Inc.(a)		63,771		4,895,062
ScottsMiracle-Gro Co.(a)		19,170		2,035,471
Sherwin-Williams Co.(a)		41,173		24,026,092
Valvoline, Inc.		97,038		2,077,584
Westlake Chemical Corp.(a)		19,417		1,362,103
WR Grace & Co.		26,890		1,878,266
				280,958,722
Commercial Services & Supplies — 0.4%
ADT, Inc.(a)		75,681		600,150
Cintas Corp.(a)		42,026		11,308,356
Clean Harbors, Inc.(b)		24,197		2,074,893
Copart, Inc.(a)(b)		100,270		9,118,554
IAA, Inc.(b)		63,921		3,008,122
KAR Auction Services, Inc.(a)		68,838		1,499,980
Republic Services, Inc.(a)		105,211		9,430,062
Rollins, Inc.(a)		68,001		2,254,913
Stericycle, Inc.(a)(b)		45,849		2,925,625
Waste Management, Inc.		210,988		24,044,193
				66,264,848
Communications Equipment — 0.9%
Arista Networks, Inc.(a)(b)		29,421		5,984,232
Ciena Corp.(b)		77,954		3,327,856
Cisco Systems, Inc.		2,136,820		102,481,887
CommScope Holding Co., Inc.(a)(b)		92,581		1,313,724
EchoStar Corp., Class A(a)(b)		24,263		1,050,831
F5 Networks, Inc.(b)		29,502		4,119,954
Juniper Networks, Inc.		165,161		4,067,916
Motorola Solutions, Inc.		85,274		13,741,052
Ubiquiti, Inc.(a)		4,263		805,622
ViaSat, Inc.(a)(b)		28,882		2,114,018
				139,007,092
Construction & Engineering — 0.1%
AECOM(a)(b)		79,444		3,426,420
Fluor Corp.(a)		67,551		1,275,363
Jacobs Engineering Group, Inc.		66,264		5,952,495
Quanta Services, Inc.(a)		73,159		2,978,303
				13,632,581
Construction Materials — 0.1%
Eagle Materials, Inc.(a)		19,562		1,773,491
Martin Marietta Materials, Inc.		30,684		8,580,473
Vulcan Materials Co.		64,623		9,305,066
				19,659,030
Consumer Finance — 0.7%
Ally Financial, Inc.		188,997		5,775,748
American Express Co.		334,281		41,614,642
Capital One Financial Corp.		232,292		23,905,170
Credit Acceptance Corp.(a)(b)		5,510		2,437,238
Discover Financial Services(a)		155,312		13,173,564
Navient Corp.(a)		102,171		1,397,699
OneMain Holdings, Inc.		32,596		1,373,921
Santander Consumer USA Holdings, Inc.(a)		49,708		1,161,676

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Consumer Finance (continued)
SLM Corp.(a)		208,224	$	1,855,276
Synchrony Financial		321,603		11,580,924
				104,275,858
Containers & Packaging — 0.4%
AptarGroup, Inc.(a)		31,639		3,658,101
Ardagh Group SA(a)		6,425		125,801
Avery Dennison Corp.		40,686		5,322,543
Ball Corp.(a)		160,829		10,400,811
Berry Global Group, Inc.(a)(b)		66,475		3,156,898
Crown Holdings, Inc.(b)		64,292		4,663,742
Graphic Packaging Holding Co.		136,660		2,275,389
International Paper Co.(a)		197,886		9,112,650
O-I Glass, Inc.(a)		89,856		1,071,982
Packaging Corp. of America(a)		47,915		5,366,001
Sealed Air Corp.		74,294		2,959,130
Silgan Holdings, Inc.		35,936		1,116,891
Sonoco Products Co.(a)		51,845		3,199,873
Westrock Co.		129,015		5,536,034
				57,965,846
Distributors — 0.1%
Genuine Parts Co.(a)		71,519		7,597,463
LKQ Corp.(b)		151,191		5,397,519
Pool Corp.(a)		19,823		4,210,009
				17,204,991
Diversified Consumer Services — 0.1%
2U, Inc.(a)(b)		24,787		594,640
Bright Horizons Family Solutions, Inc.(b)		28,371		4,263,877
frontdoor, Inc.(a)(b)		41,792		1,981,777
Graham Holdings Co., Class B		2,130		1,361,049
Grand Canyon Education, Inc.(a)(b)		22,371		2,142,918
H&R Block, Inc.(a)		95,640		2,245,627
Service Corp. International(a)		88,897		4,091,929
ServiceMaster Global Holdings, Inc.(b)		64,797		2,505,052
				19,186,869
Diversified Financial Services — 1.6%
AXA Equitable Holdings, Inc.(a)		202,642		5,021,469
Berkshire Hathaway, Inc., Class B(b)		975,680		220,991,520
FactSet Research Systems, Inc.(a)		18,528		4,971,063
Interactive Brokers Group, Inc., Class A(a)		37,593		1,752,586
Jefferies Financial Group, Inc.(a)		134,720		2,878,966
Morningstar, Inc.		9,274		1,403,249
Voya Financial, Inc.(a)		66,781		4,072,305
				241,091,158
Diversified Telecommunication Services — 1.9%
AT&T, Inc.(a)		3,641,394		142,305,678
CenturyLink, Inc.(a)		542,221		7,162,739
Verizon Communications, Inc.		2,064,210		126,742,494
Zayo Group Holdings, Inc.(b)		113,667		3,938,562
				280,149,473
Electric Utilities — 1.9%
Alliant Energy Corp.(a)		117,749		6,443,225
American Electric Power Co., Inc.(a)		245,419		23,194,550
Avangrid, Inc.(a)		29,257		1,496,788
Duke Energy Corp.(a)		361,841		33,003,518
Edison International(a)		174,501		13,159,120
Entergy Corp.		99,717		11,946,097
Evergy, Inc.		115,610		7,525,055
Eversource Energy(a)		160,930		13,690,315
Exelon Corp.		482,176		21,982,404
FirstEnergy Corp.		270,511		13,146,835
Hawaiian Electric Industries, Inc.(a)		54,040		2,532,314

Security	Shares		Value
Electric Utilities (continued)
IDACORP, Inc.		25,122	$	2,683,030
NextEra Energy, Inc.		243,528		58,972,740
OGE Energy Corp.		98,428		4,377,093
PG&E Corp.(a)(b)		272,778		2,965,097
Pinnacle West Capital Corp.		56,006		5,036,619
PPL Corp.		360,640		12,939,763
Southern Co.		516,844		32,922,963
Xcel Energy, Inc.		261,231		16,585,556
				284,603,082
Electrical Equipment — 0.5%
Acuity Brands, Inc.(a)		18,944		2,614,272
AMETEK, Inc.		113,083		11,278,898
Eaton Corp. PLC		205,733		19,487,030
Emerson Electric Co.(a)		304,530		23,223,458
GrafTech International Ltd.(a)		31,392		364,775
Hubbell, Inc.(a)		27,954		4,132,160
nVent Electric PLC(a)		71,057		1,817,638
Regal-Beloit Corp.		20,675		1,769,987
Rockwell Automation, Inc.		57,372		11,627,583
Sensata Technologies Holding PLC(a)(b)		79,007		4,256,107
				80,571,908
Electronic Equipment, Instruments & Components — 0.6%
Amphenol Corp., Class A		146,585		15,864,895
Arrow Electronics, Inc.(a)(b)		40,032		3,392,312
Avnet, Inc.(a)		51,693		2,193,851
CDW Corp.(a)		70,116		10,015,369
Cognex Corp.(a)		84,060		4,710,722
Coherent, Inc.(a)(b)		11,192		1,861,789
Corning, Inc.		377,038		10,975,576
Dolby Laboratories, Inc., Class A		30,921		2,127,365
FLIR Systems, Inc.		67,007		3,489,054
IPG Photonics Corp.(a)(b)		18,042		2,614,647
Jabil, Inc.		74,187		3,066,149
Keysight Technologies, Inc.(b)		93,951		9,642,191
Littelfuse, Inc.(a)		11,995		2,294,644
National Instruments Corp.		66,691		2,823,697
SYNNEX Corp.		21,063		2,712,914
Trimble, Inc.(b)		127,143		5,300,592
Universal Display Corp.(a)		21,362		4,402,067
Zebra Technologies Corp., Class A(a)(b)		27,079		6,917,060
				94,404,894
Energy Equipment & Services — 0.4%
Apergy Corp.(a)(b)		40,209		1,358,260
Baker Hughes Co.(a)		325,101		8,332,339
Halliburton Co.(a)		437,404		10,703,276
Helmerich & Payne, Inc.(a)		51,067		2,319,974
National Oilwell Varco, Inc.(a)		196,884		4,931,944
Patterson-UTI Energy, Inc.		90,719		952,549
Schlumberger Ltd.		694,700		27,926,940
Transocean Ltd.(a)(b)		279,997		1,926,379
				58,451,661
Entertainment — 0.9%
Activision Blizzard, Inc.		377,317		22,420,176
Electronic Arts, Inc.(b)		145,907		15,686,462
Live Nation Entertainment, Inc.(b)		64,325		4,597,308
Netflix, Inc.(b)		210,239		68,027,033
Roku, Inc.(a)(b)		43,429		5,815,143
Spotify Technology SA(b)		58,124		8,692,444
Take-Two Interactive Software, Inc.(b)		56,456		6,911,908
World Wrestling Entertainment, Inc., Class A(a)		24,370		1,580,882
				133,731,356

SCHEDULE OF INVESTMENTS 21

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Equity Real Estate Investment Trusts (REITs) — 3.6%
Alexandria Real Estate Equities, Inc.(a)		56,133	$	9,069,970
American Campus Communities, Inc.(a)		67,830		3,190,045
American Homes 4 Rent, Class A(a)		123,718		3,242,649
American Tower Corp.		219,577		50,463,186
Americold Realty Trust(a)		93,085		3,263,560
Apartment Investment & Management Co., Class A		73,273		3,784,551
Apple Hospitality REIT, Inc.(a)		96,831		1,573,504
AvalonBay Communities, Inc.(a)		70,041		14,687,598
Boston Properties, Inc.		76,911		10,602,951
Brandywine Realty Trust(a)		87,207		1,373,510
Brixmor Property Group, Inc.		142,947		3,089,085
Brookfield Property REIT, Inc., Class A(a)		34,052		628,089
Camden Property Trust		46,219		4,903,836
Chimera Investment Corp.(a)		87,273		1,794,333
Colony Capital, Inc.(a)		250,345		1,189,139
Columbia Property Trust, Inc.		54,962		1,149,256
CoreSite Realty Corp.(a)		20,002		2,242,624
Corporate Office Properties Trust(a)		46,853		1,376,541
Cousins Properties, Inc.(a)		73,157		3,014,068
Crown Castle International Corp.		205,942		29,274,655
CubeSmart(a)		94,890		2,987,137
CyrusOne, Inc.(a)		54,804		3,585,826
Digital Realty Trust, Inc.(a)		104,266		12,484,811
Douglas Emmett, Inc.		80,574		3,537,199
Duke Realty Corp.(a)		187,490		6,500,278
Empire State Realty Trust, Inc., Class A(a)		77,941		1,088,056
EPR Properties(a)		40,258		2,843,825
Equinix, Inc.		42,377		24,735,455
Equity Commonwealth		58,865		1,932,538
Equity LifeStyle Properties, Inc.(a)		88,279		6,213,959
Equity Residential(a)		181,356		14,675,328
Essex Property Trust, Inc.		32,821		9,874,526
Extra Space Storage, Inc.(a)		63,963		6,755,772
Federal Realty Investment Trust(a)		37,784		4,863,934
Gaming and Leisure Properties, Inc.		100,466		4,325,061
Healthcare Trust of America, Inc., Class A(a)		106,941		3,238,174
Healthpeak Properties, Inc.		241,628		8,328,917
Highwoods Properties, Inc.(a)		50,111		2,450,929
Host Hotels & Resorts, Inc.(a)		354,200		6,570,410
Hudson Pacific Properties, Inc.		73,745		2,776,499
Invitation Homes, Inc.		265,129		7,945,916
Iron Mountain, Inc.(a)		143,103		4,560,693
JBG SMITH Properties(a)		62,797		2,504,972
Kilroy Realty Corp.(a)		50,456		4,233,258
Kimco Realty Corp.		197,416		4,088,485
Lamar Advertising Co., Class A(a)		42,198		3,766,594
Liberty Property Trust		78,306		4,702,275
Life Storage, Inc.		22,221		2,406,090
Macerich Co.(a)		66,302		1,784,850
Medical Properties Trust, Inc.(a)		258,258		5,451,826
MFA Financial, Inc.(a)		211,876		1,620,851
Mid-America Apartment Communities, Inc.		55,565		7,326,801
National Retail Properties, Inc.(a)		85,095		4,562,794
New Residential Investment Corp.(a)		214,584		3,456,948
Omega Healthcare Investors, Inc.(a)		107,101		4,535,727
Outfront Media, Inc.(a)		74,700		2,003,454
Paramount Group, Inc.(a)		106,000		1,475,520
Park Hotels & Resorts, Inc.(a)		113,524		2,936,866
Prologis, Inc.		311,752		27,789,573
Public Storage(a)		74,308		15,824,632
Rayonier, Inc.(a)		63,500		2,080,260
Realty Income Corp.		162,765		11,984,387
Regency Centers Corp.		81,103		5,116,788
Retail Properties of America, Inc., Class A		110,576		1,481,718

Security	Shares		Value
Equity Real Estate Investment Trusts (REITs) (continued)
SBA Communications Corp.		56,080	$	13,514,719
Service Properties Trust(a)		79,912		1,944,259
Simon Property Group, Inc.(a)		152,534		22,721,465
SITE Centers Corp.		82,245		1,153,075
SL Green Realty Corp.		38,657		3,551,805
Spirit Realty Capital, Inc.(a)		49,335		2,426,295
Starwood Property Trust, Inc.(a)		131,719		3,274,534
STORE Capital Corp.(a)		105,320		3,922,117
Sun Communities, Inc.		45,808		6,875,781
Taubman Centers, Inc.(a)		26,329		818,569
UDR, Inc.		144,098		6,729,377
Ventas, Inc.		186,263		10,754,826
VEREIT, Inc.(a)		542,707		5,014,613
VICI Properties, Inc.(a)		231,348		5,910,941
Vornado Realty Trust		85,895		5,712,018
Weingarten Realty Investors(a)		56,750		1,772,870
Welltower, Inc.		200,822		16,423,223
Weyerhaeuser Co.(a)		371,017		11,204,713
WP Carey, Inc.		84,601		6,771,464
				543,819,726
Food & Staples Retailing — 1.4%
Casey’s General Stores, Inc.(a)		17,657		2,807,286
Costco Wholesale Corp.		219,319		64,462,240
Grocery Outlet Holding Corp.(a)(b)		17,773		576,734
Kroger Co.(a)		394,034		11,423,046
Sprouts Farmers Market, Inc.(b)		54,669		1,057,845
Sysco Corp.(a)		237,922		20,351,848
U.S. Foods Holding Corp.(b)		106,972		4,481,057
Walgreens Boots Alliance, Inc.(a)		373,618		22,028,517
Walmart, Inc.		700,390		83,234,348
				210,422,921
Food Products — 1.1%
Archer-Daniels-Midland Co.		278,653		12,915,567
Beyond Meat, Inc.(a)(b)		23,606		1,784,614
Bunge Ltd.(a)		68,346		3,933,312
Campbell Soup Co.(a)		80,765		3,991,406
Conagra Brands, Inc.(a)		240,043		8,219,072
Flowers Foods, Inc.(a)		102,672		2,232,089
General Mills, Inc.(a)		297,066		15,910,855
Hain Celestial Group, Inc.(a)(b)		39,847		1,034,229
Hershey Co.		72,291		10,625,331
Hormel Foods Corp.(a)		140,231		6,325,820
Ingredion, Inc.(a)		32,033		2,977,467
J.M. Smucker Co.(a)		53,707		5,592,510
Kellogg Co.(a)		122,992		8,506,127
Kraft Heinz Co.(a)		314,866		10,116,645
Lamb Weston Holdings, Inc.		72,667		6,251,542
McCormick & Co., Inc.(a)		60,688		10,300,574
Mondelez International, Inc., Class A(a)		711,558		39,192,615
Pilgrim’s Pride Corp.(b)		28,135		920,436
Post Holdings, Inc.(b)		31,767		3,465,780
TreeHouse Foods, Inc.(a)(b)		27,098		1,314,253
Tyson Foods, Inc., Class A		144,967		13,197,796
				168,808,040
Gas Utilities — 0.1%
Atmos Energy Corp.		59,520		6,657,907
National Fuel Gas Co.(a)		43,998		2,047,667
UGI Corp.(a)		103,503		4,674,196
				13,379,770
Health Care Equipment & Supplies — 3.4%
Abbott Laboratories		859,039		74,616,128
ABIOMED, Inc.(a)(b)		21,895		3,735,068
Align Technology, Inc.(a)(b)		39,322		10,972,411

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Health Care Equipment & Supplies (continued)
Baxter International, Inc.		240,674	$	20,125,160
Becton Dickinson & Co.(a)		133,003		36,172,826
Boston Scientific Corp.(b)		689,669		31,186,832
Cantel Medical Corp.(a)		17,701		1,255,001
Cooper Cos., Inc.		24,268		7,797,066
Danaher Corp.		305,613		46,905,483
DENTSPLY SIRONA, Inc.		112,348		6,357,773
DexCom, Inc.(b)		44,811		9,801,958
Edwards Lifesciences Corp.(b)		103,064		24,043,801
Envista Holdings Corp.(b)		72,360		2,144,750
Hill-Rom Holdings, Inc.		32,346		3,672,241
Hologic, Inc.(b)		130,448		6,810,690
ICU Medical, Inc.(a)(b)		8,920		1,669,110
IDEXX Laboratories, Inc.(b)		42,209		11,022,036
Insulet Corp.(a)(b)		29,176		4,994,931
Integra LifeSciences Holdings Corp.(a)(b)		34,147		1,990,087
Intuitive Surgical, Inc.(b)		56,905		33,639,391
Masimo Corp.(b)		23,837		3,767,676
Medtronic PLC(a)		669,378		75,940,934
ResMed, Inc.(a)		70,884		10,984,894
STERIS PLC		40,952		6,241,904
Stryker Corp.(a)		170,386		35,770,837
Teleflex, Inc.		22,677		8,536,530
Varian Medical Systems, Inc.(b)		44,952		6,383,634
West Pharmaceutical Services, Inc.		35,489		5,335,061
Zimmer Biomet Holdings, Inc.(a)		101,340		15,168,571
				507,042,784
Health Care Providers & Services — 2.7%
Acadia Healthcare Co., Inc.(a)(b)		41,453		1,377,069
AmerisourceBergen Corp.		76,466		6,501,139
Anthem, Inc.(a)		126,498		38,206,191
Cardinal Health, Inc.(a)		148,324		7,502,228
Centene Corp.(b)		205,152		12,897,906
Chemed Corp.		8,070		3,544,828
Cigna Corp.(b)		182,715		37,363,390
Covetrus, Inc.(a)(b)		44,670		589,644
CVS Health Corp.(a)		648,856		48,203,512
DaVita, Inc.(b)		49,333		3,701,455
Encompass Health Corp.(a)		46,965		3,253,266
Guardant Health, Inc.(a)(b)		19,531		1,526,152
HCA Healthcare, Inc.		133,567		19,742,538
Henry Schein, Inc.(a)(b)		71,797		4,790,296
Humana, Inc.		65,950		24,171,994
Laboratory Corp. of America Holdings(b)		47,988		8,118,130
McKesson Corp.		89,752		12,414,497
MEDNAX, Inc.(a)(b)		38,070		1,057,965
Molina Healthcare, Inc.(a)(b)		30,860		4,187,394
Penumbra, Inc.(b)		15,426		2,534,029
Premier, Inc., Class A(a)(b)		29,685		1,124,468
Quest Diagnostics, Inc.(a)		68,082		7,270,477
UnitedHealth Group, Inc.		471,401		138,582,466
Universal Health Services, Inc., Class B		38,550		5,530,383
WellCare Health Plans, Inc.(b)		24,662		8,143,639
				402,335,056
Health Care Technology — 0.1%
Cerner Corp.		156,325		11,472,692
Change Healthcare, Inc.(a)(b)		23,069		378,101
Veeva Systems, Inc., Class A(b)		65,397		9,198,742
				21,049,535
Hotels, Restaurants & Leisure — 2.0%
Aramark(a)		125,474		5,445,572
Caesars Entertainment Corp.(a)(b)		284,087		3,863,583
Carnival Corp.(a)		201,403		10,237,315

Security	Shares		Value
Hotels, Restaurants & Leisure (continued)
Chipotle Mexican Grill, Inc.(b)		12,757	$	10,679,012
Choice Hotels International, Inc.(a)		15,480		1,601,096
Darden Restaurants, Inc.(a)		61,336		6,686,237
Domino’s Pizza, Inc.(a)		20,423		5,999,869
Dunkin’ Brands Group, Inc.(a)		42,150		3,184,011
Extended Stay America, Inc.		91,249		1,355,960
Hilton Grand Vacations, Inc.(b)		44,098		1,516,530
Hilton Worldwide Holdings, Inc.		139,546		15,477,047
Hyatt Hotels Corp., Class A(a)		18,022		1,616,754
International Game Technology PLC(a)		55,334		828,350
Las Vegas Sands Corp.(a)		170,886		11,797,969
Marriott International, Inc., Class A(a)		136,647		20,692,455
McDonald’s Corp.(a)		375,840		74,269,742
MGM Resorts International		247,550		8,235,989
Norwegian Cruise Line Holdings Ltd.(b)		103,335		6,035,797
Planet Fitness, Inc., Class A(b)		38,849		2,901,243
Royal Caribbean Cruises Ltd.(a)		85,799		11,455,025
Six Flags Entertainment Corp.(a)		36,963		1,667,401
Starbucks Corp.		588,858		51,772,395
Vail Resorts, Inc.(a)		20,278		4,863,273
Wendy’s Co.(a)		91,693		2,036,502
Wyndham Destinations, Inc.(a)		45,887		2,371,899
Wyndham Hotels & Resorts, Inc.(a)		45,826		2,878,331
Wynn Resorts Ltd.		49,169		6,828,099
Yum China Holdings, Inc.(a)		182,103		8,742,765
Yum! Brands, Inc.		151,060		15,216,274
				300,256,495
Household Durables — 0.4%
D.R. Horton, Inc.(a)		168,600		8,893,650
Garmin Ltd.		72,616		7,084,417
Leggett & Platt, Inc.(a)		66,425		3,376,383
Lennar Corp., Class A(a)		137,217		7,655,336
Lennar Corp., Class B		10,779		481,821
Mohawk Industries, Inc.(b)		29,446		4,015,846
Newell Brands, Inc.(a)		188,436		3,621,740
NVR, Inc.(b)		1,645		6,264,834
PulteGroup, Inc.		125,969		4,887,597
Tempur Sealy International, Inc.(b)		22,517		1,960,330
Toll Brothers, Inc.(a)		64,576		2,551,398
Whirlpool Corp.(a)		31,456		4,640,704
				55,434,056
Household Products — 1.5%
Church & Dwight Co., Inc.		124,509		8,757,963
Clorox Co.(a)		63,662		9,774,663
Colgate-Palmolive Co.(a)		417,568		28,745,381
Energizer Holdings, Inc.(a)		31,553		1,584,592
Kimberly-Clark Corp.(a)		169,590		23,327,104
Procter & Gamble Co.		1,232,870		153,985,463
Spectrum Brands Holdings, Inc.(a)		19,640		1,262,656
				227,437,822
Independent Power and Renewable Electricity Producers — 0.1%
AES Corp.(a)		325,379		6,475,042
NRG Energy, Inc.		124,933		4,966,087
Vistra Energy Corp.(a)		210,776		4,845,740
				16,286,869
Industrial Conglomerates — 1.2%
3M Co.		279,678		49,340,793
BWX Technologies, Inc.(a)		48,529		3,012,680
Carlisle Cos., Inc.(a)		28,592		4,627,329
General Electric Co.		4,325,333		48,270,716
Honeywell International, Inc.		358,943		63,532,911
Roper Technologies, Inc.(a)		51,290		18,168,457
Seaboard Corp.(a)		134		569,574
				187,522,460

SCHEDULE OF INVESTMENTS 23

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Insurance — 2.5%
Aflac, Inc.		361,997	$	19,149,641
Alleghany Corp.(b)		6,775		5,417,087
Allstate Corp.		161,171		18,123,679
American Financial Group, Inc.		36,447		3,996,414
American International Group, Inc.		432,201		22,184,877
American National Insurance Co.		2,683		315,735
Aon PLC		116,479		24,261,411
Arch Capital Group Ltd.(a)(b)		193,845		8,314,012
Arthur J Gallagher & Co.		90,298		8,599,079
Assurant, Inc.(a)		30,648		4,017,340
Assured Guaranty Ltd.		44,992		2,205,508
Athene Holding Ltd., Class A(b)		70,215		3,302,211
Axis Capital Holdings Ltd.		40,019		2,378,729
Brighthouse Financial, Inc.(b)		52,917		2,075,934
Brown & Brown, Inc.(a)		116,973		4,618,094
Chubb Ltd.(a)		224,274		34,910,491
Cincinnati Financial Corp.		76,312		8,024,207
CNA Financial Corp.(a)		11,537		516,973
Erie Indemnity Co., Class A(a)		12,991		2,156,506
Everest Re Group Ltd.(a)		19,822		5,487,522
Fidelity National Financial, Inc.		132,557		6,011,460
First American Financial Corp.		53,624		3,127,352
Globe Life, Inc.(a)		52,535		5,529,309
Hanover Insurance Group, Inc.(a)		18,875		2,579,646
Hartford Financial Services Group, Inc.(a)		178,992		10,877,344
Kemper Corp.(a)		31,257		2,422,417
Lincoln National Corp.		98,297		5,800,506
Loews Corp.(a)		127,999		6,718,667
Markel Corp.(b)		6,705		7,664,955
Marsh & McLennan Cos., Inc.(a)		254,046		28,303,265
Mercury General Corp.		13,156		641,092
MetLife, Inc.		387,703		19,761,222
Old Republic International Corp.		135,330		3,027,332
Primerica, Inc.		20,957		2,736,146
Principal Financial Group, Inc.		138,919		7,640,545
Progressive Corp.		290,527		21,031,250
Prudential Financial, Inc.(a)		202,765		19,007,191
Reinsurance Group of America, Inc.(a)		30,696		5,005,290
RenaissanceRe Holdings Ltd.		21,742		4,261,867
Travelers Cos., Inc.		128,841		17,644,775
Unum Group		104,440		3,045,470
W.R. Berkley Corp.		72,509		5,010,372
White Mountains Insurance Group Ltd.(a)		1,444		1,610,796
Willis Towers Watson PLC		64,004		12,924,968
				382,438,687
Interactive Media & Services — 4.4%
Alphabet, Inc., Class A(a)(b)		149,339		200,023,163
Alphabet, Inc., Class C(b)		149,546		199,945,993
Facebook, Inc., Class A(b)		1,191,985		244,654,921
IAC/InterActiveCorp.(b)		37,544		9,352,586
Match Group, Inc.(a)(b)		25,542		2,097,254
Twitter, Inc.(b)		376,436		12,064,774
Zillow Group, Inc., Class A(b)		25,163		1,150,956
Zillow Group, Inc., Class C(a)(b)		64,526		2,964,324
				672,253,971
Internet & Direct Marketing Retail — 3.0%
Amazon.com, Inc.(b)		206,289		381,189,066
Booking Holdings, Inc.(b)		20,828		42,775,088
eBay, Inc.(a)		383,827		13,859,993
Etsy, Inc.(a)(b)		59,272		2,625,750
Expedia Group, Inc.(a)		67,793		7,331,135
GrubHub, Inc.(a)(b)		46,591		2,266,186
Qurate Retail, Inc., Series A(b)		197,866		1,668,010

Security	Shares		Value
Internet & Direct Marketing Retail (continued)
TripAdvisor, Inc.(a)		49,575	$	1,506,089
Wayfair, Inc., Class A(a)(b)		30,840		2,787,011
				456,008,328
IT Services — 5.2%
Accenture PLC, Class A(a)		318,115		66,985,476
Akamai Technologies, Inc.(a)(b)		79,634		6,878,785
Alliance Data Systems Corp.		20,630		2,314,686
Amdocs Ltd.(a)		66,066		4,769,305
Automatic Data Processing, Inc.		216,155		36,854,427
Black Knight, Inc.(a)(b)		72,280		4,660,614
Booz Allen Hamilton Holding Corp.		66,587		4,736,333
Broadridge Financial Solutions, Inc.(a)		56,628		6,995,823
CACI International, Inc., Class A(b)		12,384		3,095,876
Cognizant Technology Solutions Corp., Class A(a)		272,857		16,922,591
CoreLogic, Inc.(a)(b)		36,221		1,583,220
DXC Technology Co.		123,540		4,643,869
EPAM Systems, Inc.(b)		25,995		5,515,099
Euronet Worldwide, Inc.(b)		24,640		3,882,278
Fidelity National Information Services, Inc.		305,118		42,438,863
Fiserv, Inc.(a)(b)		280,131		32,391,548
FleetCor Technologies, Inc.(b)		42,342		12,182,640
Gartner, Inc.(b)		43,996		6,779,784
Genpact Ltd.		92,702		3,909,243
Global Payments, Inc.		147,998		27,018,515
GoDaddy, Inc., Class A(a)(b)		84,376		5,730,818
International Business Machines Corp.		442,881		59,363,769
Jack Henry & Associates, Inc.(a)		37,916		5,523,224
Leidos Holdings, Inc.		67,876		6,644,382
Mastercard, Inc., Class A		442,203		132,037,394
MongoDB, Inc.(a)(b)		19,907		2,619,960
Okta, Inc.(a)(b)		50,944		5,877,409
Paychex, Inc.(a)		159,454		13,563,157
PayPal Holdings, Inc.(b)		586,435		63,434,674
Sabre Corp.		142,477		3,197,184
Square, Inc., Class A(b)		170,303		10,654,156
Switch, Inc., Class A(a)		29,808		441,755
Teradata Corp.(a)(b)		57,517		1,539,730
Twilio, Inc., Class A(a)(b)		59,662		5,863,581
VeriSign, Inc.(b)		50,830		9,793,924
Visa, Inc., Class A(a)		854,573		160,574,267
Western Union Co.		208,229		5,576,373
WEX, Inc.(a)(b)		21,618		4,528,106
				791,522,838
Leisure Products — 0.1%
Brunswick Corp.		38,541		2,311,689
Hasbro, Inc.(a)		61,677		6,513,708
Mattel, Inc.(a)(b)		165,131		2,237,525
Polaris Industries, Inc.(a)		29,932		3,044,085
				14,107,007
Life Sciences Tools & Services — 1.1%
Adaptive Biotechnologies Corp.(a)(b)		7,827		234,184
Agilent Technologies, Inc.		154,293		13,162,736
Avantor, Inc.(b)		156,734		2,844,722
Bio-Rad Laboratories, Inc., Class A(b)		10,473		3,875,324
Bio-Techne Corp.		18,922		4,153,568
Bruker Corp.(a)		53,452		2,724,449
Charles River Laboratories International, Inc.(b)		23,961		3,660,282
Illumina, Inc.(a)(b)		72,876		24,175,884
IQVIA Holdings, Inc.(b)		87,991		13,595,490
Mettler-Toledo International, Inc.(b)		11,965		9,491,595
PerkinElmer, Inc.(a)		54,981		5,338,655
PRA Health Sciences, Inc.(b)		30,280		3,365,622
QIAGEN NV(b)		111,759		3,777,454

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Life Sciences Tools & Services (continued)
Thermo Fisher Scientific, Inc.		199,017	$	64,654,653
Waters Corp.(a)(b)		31,614		7,386,611
				162,441,229
Machinery — 1.8%
AGCO Corp.(a)		29,823		2,303,827
Allison Transmission Holdings, Inc.		53,386		2,579,611
Caterpillar, Inc.		267,283		39,472,353
Colfax Corp.(a)(b)		44,816		1,630,406
Crane Co.		25,215		2,178,072
Cummins, Inc.(a)		74,520		13,336,099
Deere & Co.(a)		156,339		27,087,295
Donaldson Co., Inc.(a)		63,918		3,682,955
Dover Corp.		72,489		8,355,082
Flowserve Corp.(a)		63,215		3,146,211
Fortive Corp.		147,079		11,235,365
Gardner Denver Holdings, Inc.(a)(b)		68,039		2,495,671
Gates Industrial Corp. PLC(a)(b)		16,568		227,976
Graco, Inc.(a)		82,773		4,304,196
IDEX Corp.(a)		37,526		6,454,472
Illinois Tool Works, Inc.(a)		159,505		28,651,883
Ingersoll-Rand PLC(a)		119,715		15,912,518
ITT, Inc.		42,392		3,133,193
Lincoln Electric Holdings, Inc.(a)		29,635		2,866,594
Middleby Corp.(a)(b)		27,110		2,969,087
Nordson Corp.		28,269		4,603,324
Oshkosh Corp.		34,253		3,242,046
PACCAR, Inc.(a)		168,079		13,295,049
Parker-Hannifin Corp.		63,425		13,054,133
Pentair PLC		86,845		3,983,580
Snap-on, Inc.(a)		26,956		4,566,346
Stanley Black & Decker, Inc.		75,955		12,588,782
Timken Co.(a)		31,663		1,782,944
Toro Co.		52,705		4,199,007
Trinity Industries, Inc.(a)		50,694		1,122,872
Valmont Industries, Inc.		10,037		1,503,342
WABCO Holdings, Inc.(b)		24,811		3,361,890
Westinghouse Air Brake Technologies Corp.		88,186		6,860,871
Woodward, Inc.		27,450		3,251,178
Xylem, Inc.(a)		89,666		7,064,784
				266,503,014
Marine — 0.0%
Kirby Corp.(a)(b)		29,584		2,648,656
Media — 2.4%
Altice USA, Inc., Class A(b)		146,674		4,010,067
AMC Networks, Inc., Class A(b)		20,274		800,823
Cable One, Inc.(a)		2,233		3,323,753
Charter Communications, Inc., Class A(a)(b)		76,516		37,116,381
Cinemark Holdings, Inc.(a)		52,241		1,768,358
Comcast Corp., Class A		2,246,380		101,019,709
Discovery, Inc., Class A(a)(b)		74,562		2,441,160
Discovery, Inc., Class C(b)		167,053		5,093,446
DISH Network Corp., Class A(b)		131,985		4,681,508
Fox Corp., Class A(a)		175,385		6,501,522
Fox Corp., Class B(b)		77,600		2,824,640
GCI Liberty, Inc., Class A(b)		50,779		3,597,692
Interpublic Group of Cos., Inc.		190,291		4,395,722
John Wiley & Sons, Inc., Class A(a)		19,515		946,868
Liberty Broadband Corp., Class A(b)		12,544		1,562,481
Liberty Broadband Corp., Class C(b)		52,061		6,546,671
Liberty Media Corp. — Liberty Formula One, Class A(a)(b)		14,208		622,026
Liberty Media Corp. — Liberty Formula One, Class C(a)(b)		96,580		4,439,300

Security	Shares		Value
Media (continued)
Liberty Media Corp. — Liberty SiriusXM, Class A(a)(b)		42,844	$	2,071,079
Liberty Media Corp. — Liberty SiriusXM, Class C(b)		77,968		3,753,379
Lions Gate Entertainment Corp., Class A(a)(b)		19,444		207,273
Lions Gate Entertainment Corp., Class B(b)		41,348		410,586
Madison Square Garden Co., Class A(a)(b)		8,771		2,580,340
New York Times Co., Class A(a)		82,857		2,665,510
News Corp., Class A(a)		202,510		2,863,491
News Corp., Class B(a)		53,107		770,583
Nexstar Media Group, Inc., Class A(a)		22,849		2,679,045
Omnicom Group, Inc.(a)		108,870		8,820,647
Sinclair Broadcast Group, Inc., Class A(a)		27,357		912,082
Sirius XM Holdings, Inc.(a)		697,687		4,988,462
ViacomCBS, Inc., Class A Class A(a)		1,462		65,600
ViacomCBS, Inc., Class B Class B(a)		267,310		11,219,001
Walt Disney Co.		870,785		125,941,635
				361,640,840
Metals & Mining — 0.3%
Alcoa Corp.(b)		94,543		2,033,620
Freeport-McMoRan, Inc.(a)		721,964		9,472,168
Newmont Goldcorp Corp.		405,517		17,619,714
Nucor Corp.(a)		153,194		8,621,758
Reliance Steel & Aluminum Co.		31,789		3,807,051
Royal Gold, Inc.(a)		33,978		4,153,810
Southern Copper Corp.(a)		38,273		1,625,837
Steel Dynamics, Inc.(a)		99,982		3,403,387
United States Steel Corp.(a)		86,386		985,664
				51,723,009
Mortgage Real Estate Investment Trusts (REITs) — 0.1%
AGNC Investment Corp.(a)		276,995		4,897,271
Annaly Capital Management, Inc.(a)		722,309		6,804,151
Two Harbors Investment Corp.(a)		143,603		2,099,476
				13,800,898
Multi-Utilities — 1.0%
Ameren Corp.		122,968		9,443,942
CenterPoint Energy, Inc.(a)		249,604		6,806,701
CMS Energy Corp.		142,413		8,949,233
Consolidated Edison, Inc.		164,935		14,921,669
Dominion Energy, Inc.		409,864		33,944,936
DTE Energy Co.(a)		92,317		11,989,209
MDU Resources Group, Inc.		103,705		3,081,076
NiSource, Inc.		182,127		5,070,416
Public Service Enterprise Group, Inc.		250,507		14,792,438
Sempra Energy		140,562		21,292,332
WEC Energy Group, Inc.(a)		157,751		14,549,375
				144,841,327
Multiline Retail — 0.5%
Dollar General Corp.		129,220		20,155,736
Dollar Tree, Inc.(b)		116,488		10,955,696
Kohl’s Corp.(a)		79,522		4,051,646
Macy’s, Inc.(a)		161,073		2,738,241
Nordstrom, Inc.(a)		51,684		2,115,426
Ollie’s Bargain Outlet Holdings, Inc.(a)(b)		28,346		1,851,277
Target Corp.		247,570		31,740,950
				73,608,972
Oil, Gas & Consumable Fuels — 3.6%
Antero Midstream Corp.(a)		151,287		1,148,268
Antero Resources Corp.(b)		99,281		282,951
Apache Corp.(a)		182,210		4,662,754
Cabot Oil & Gas Corp.(a)		208,380		3,627,896
Centennial Resource Development, Inc., Class A(a)(b)		75,919		350,746
Cheniere Energy, Inc.(b)		116,598		7,120,640
Chesapeake Energy Corp.(a)(b)		590,525		487,537

SCHEDULE OF INVESTMENTS 25

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Oil, Gas & Consumable Fuels (continued)
Chevron Corp.(a)		950,854	$	114,587,416
Cimarex Energy Co.		50,084		2,628,909
Concho Resources, Inc.(a)		98,296		8,607,781
ConocoPhillips		547,372		35,595,601
Continental Resources, Inc.(a)		38,965		1,336,500
Devon Energy Corp.(a)		187,996		4,882,256
Diamondback Energy, Inc.		80,877		7,510,238
EOG Resources, Inc.		288,794		24,189,385
EQT Corp.(a)		121,496		1,324,306
Equitrans Midstream Corp.(a)		93,682		1,251,592
Exxon Mobil Corp.(a)		2,111,370		147,331,399
Hess Corp.(a)		135,873		9,077,675
HollyFrontier Corp.		74,223		3,763,848
Kinder Morgan, Inc.(a)		972,620		20,590,365
Kosmos Energy Ltd.(a)		162,235		924,740
Marathon Oil Corp.		396,735		5,387,661
Marathon Petroleum Corp.		320,744		19,324,826
Murphy Oil Corp.(a)		79,843		2,139,792
Noble Energy, Inc.(a)		241,183		5,990,986
Occidental Petroleum Corp.(a)		447,975		18,461,050
ONEOK, Inc.(a)		206,909		15,656,804
Parsley Energy, Inc., Class A		126,731		2,396,483
PBF Energy, Inc., Class A		61,053		1,915,233
Phillips 66		222,802		24,822,371
Pioneer Natural Resources Co.(a)		81,519		12,339,531
Range Resources Corp.(a)		89,120		432,232
Targa Resources Corp.(a)		111,132		4,537,520
Valero Energy Corp.		204,359		19,138,220
Williams Cos., Inc.(a)		599,359		14,216,795
WPX Energy, Inc.(a)(b)		212,659		2,921,935
				550,964,242
Paper & Forest Products — 0.0%
Domtar Corp.(a)		26,519		1,014,087
Personal Products — 0.2%
Coty, Inc., Class A(a)		132,586		1,491,592
Estee Lauder Cos., Inc., Class A(a)		108,646		22,439,745
Herbalife Nutrition Ltd.(a)(b)		46,378		2,210,839
Nu Skin Enterprises, Inc., Class A(a)		28,665		1,174,692
				27,316,868
Pharmaceuticals — 4.2%
Allergan PLC		162,920		31,145,416
Bristol-Myers Squibb Co.		1,166,474		74,875,966
Catalent, Inc.(b)		73,217		4,122,117
Elanco Animal Health, Inc.(a)(b)		185,508		5,463,211
Eli Lilly & Co.(a)		424,214		55,754,446
Horizon Therapeutics PLC(b)		93,321		3,378,220
Jazz Pharmaceuticals PLC(b)		28,584		4,267,020
Johnson & Johnson		1,324,972		193,273,666
Merck & Co., Inc.(a)		1,270,427		115,545,336
Mylan NV(b)		255,099		5,127,490
Nektar Therapeutics(a)(b)		90,298		1,949,082
Perrigo Co. PLC(a)		65,638		3,390,859
Pfizer, Inc.(a)		2,774,873		108,719,524
Zoetis, Inc.		237,871		31,482,227
				638,494,580
Professional Services — 0.4%
CoStar Group, Inc.(b)		17,901		10,710,168
Equifax, Inc.(a)		60,816		8,521,538
IHS Markit Ltd.(b)		198,245		14,937,761
ManpowerGroup, Inc.		28,955		2,811,531
Nielsen Holdings PLC		176,041		3,573,632
Paylocity Holding Corp.(a)(b)		17,148		2,071,821

Security	Shares		Value
Professional Services (continued)
Robert Half International, Inc.		58,080	$	3,667,752
TransUnion		92,188		7,892,215
Verisk Analytics, Inc.		79,279		11,839,526
				66,025,944
Real Estate Management & Development — 0.1%
CBRE Group, Inc., Class A(b)		168,109		10,303,401
Howard Hughes Corp.(a)(b)		21,016		2,664,829
Jones Lang LaSalle, Inc.		25,626		4,461,230
				17,429,460
Road & Rail — 1.1%
AMERCO(a)		4,300		1,616,026
CSX Corp.		371,819		26,904,823
JB Hunt Transport Services, Inc.(a)		41,907		4,893,899
Kansas City Southern(a)		49,360		7,559,978
Knight-Swift Transportation Holdings, Inc.(a)		58,602		2,100,296
Landstar System, Inc.(a)		21,119		2,404,820
Lyft, Inc., Class A(b)		94,716		4,074,682
Norfolk Southern Corp.(a)		129,997		25,236,318
Old Dominion Freight Line, Inc.(a)		32,874		6,238,828
Ryder System, Inc.		26,032		1,413,798
Schneider National, Inc., Class B		30,004		654,687
Uber Technologies, Inc.(a)(b)		472,401		14,049,206
Union Pacific Corp.		346,337		62,614,266
				159,761,627
Semiconductors & Semiconductor Equipment — 3.9%
Advanced Micro Devices, Inc.(a)(b)		513,978		23,571,031
Analog Devices, Inc.		183,268		21,779,569
Applied Materials, Inc.		459,270		28,033,841
Broadcom, Inc.(a)		192,820		60,934,976
Cree, Inc.(a)(b)		52,200		2,409,030
Cypress Semiconductor Corp.(a)		179,165		4,179,920
Entegris, Inc.(a)		65,510		3,281,396
First Solar, Inc.(a)(b)		42,386		2,371,921
Intel Corp.		2,171,352		129,955,417
KLA Corp.(a)		79,879		14,232,041
Lam Research Corp.		71,725		20,972,390
Marvell Technology Group Ltd.(a)		331,032		8,792,210
Maxim Integrated Products, Inc.		137,488		8,456,887
Microchip Technology, Inc.(a)		115,644		12,110,240
Micron Technology, Inc.(b)		549,371		29,545,172
MKS Instruments, Inc.(a)		26,952		2,964,990
Monolithic Power Systems, Inc.(a)		20,606		3,668,280
NVIDIA Corp.		291,209		68,521,478
ON Semiconductor Corp.(a)(b)		205,685		5,014,600
Qorvo, Inc.(b)		57,628		6,698,102
QUALCOMM, Inc.(a)		569,625		50,258,014
Skyworks Solutions, Inc.		85,879		10,381,054
Teradyne, Inc.		81,328		5,545,756
Texas Instruments, Inc.(a)		468,137		60,057,296
Xilinx, Inc.		126,169		12,335,543
				596,071,154
Software — 7.2%
Adobe, Inc.(b)		242,867		80,099,965
Alteryx, Inc., Class A(a)(b)		24,012		2,402,881
Anaplan, Inc.(b)		42,974		2,251,838
ANSYS, Inc.(a)(b)		42,152		10,850,346
Aspen Technology, Inc.(b)		34,907		4,221,304
Atlassian Corp. PLC, Class A(a)(b)		58,436		7,032,188
Autodesk, Inc.(b)		109,381		20,067,038
Avalara, Inc.(b)		23,359		1,711,047
Cadence Design Systems, Inc.(b)		139,463		9,673,154
CDK Global, Inc.(a)		61,638		3,370,366

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Software (continued)
Cerence Inc.(a)(b)		17,330	$	392,178
Ceridian HCM Holding, Inc.(a)(b)		45,141		3,064,171
Citrix Systems, Inc.		62,847		6,969,732
Coupa Software, Inc.(a)(b)		31,593		4,620,476
DocuSign, Inc.(a)(b)		77,913		5,774,132
Dropbox, Inc., Class A(b)		110,077		1,971,479
Dynatrace, Inc.(b)		31,715		802,390
Elastic NV(b)		21,103		1,356,923
Fair Isaac Corp.(b)		13,966		5,232,781
FireEye, Inc.(b)		103,414		1,709,433
Fortinet, Inc.(b)		72,386		7,727,929
Guidewire Software, Inc.(a)(b)		40,218		4,414,730
HubSpot, Inc.(a)(b)		19,263		3,053,185
Intuit, Inc.(a)		123,642		32,385,549
LogMeIn, Inc.(a)		22,470		1,926,578
Manhattan Associates, Inc.(a)(b)		31,244		2,491,709
Medallia, Inc.(a)(b)		8,487		264,031
Microsoft Corp.		3,772,597		594,938,547
New Relic, Inc.(b)		25,596		1,681,913
NortonLifeLock, Inc.		293,725		7,495,862
Nuance Communications, Inc.(a)(b)		138,645		2,472,040
Nutanix, Inc., Class A(a)(b)		84,140		2,630,216
Oracle Corp.		1,024,169		54,260,474
PagerDuty, Inc.(b)		20,928		489,506
Palo Alto Networks, Inc.(b)		47,462		10,975,587
Paycom Software, Inc.(a)(b)		24,833		6,574,785
Pegasystems, Inc.(a)		18,050		1,437,683
Pluralsight, Inc., Class A(a)(b)		32,028		551,202
Proofpoint, Inc.(b)		26,842		3,080,925
PTC, Inc.(b)		51,544		3,860,130
RealPage, Inc.(a)(b)		40,928		2,199,880
RingCentral, Inc., Class A(a)(b)		37,054		6,249,898
salesforce.com, Inc.(b)		414,061		67,342,881
ServiceNow, Inc.(b)		92,529		26,122,787
Smartsheet, Inc., Class A(a)(b)		46,552		2,091,116
SolarWinds Corp.(a)(b)		28,404		526,894
Splunk, Inc.(a)(b)		76,977		11,528,845
SS&C Technologies Holdings, Inc.(a)		110,047		6,756,886
Synopsys, Inc.(b)		73,318		10,205,866
Trade Desk, Inc., Class A(a)(b)		19,768		5,135,331
Tyler Technologies, Inc.(b)		18,679		5,604,074
VMware, Inc., Class A(a)(b)		37,373		5,672,848
Workday, Inc., Class A(b)		80,960		13,313,872
Zendesk, Inc.(b)		54,286		4,159,936
Zscaler, Inc.(a)(b)		34,268		1,593,462
Zynga, Inc., Class A(b)		433,541		2,653,271
				1,087,444,250
Specialty Retail — 2.1%
Advance Auto Parts, Inc.(a)		32,056		5,134,089
AutoNation, Inc.(b)		27,108		1,318,262
AutoZone, Inc.(b)		11,779		14,032,441
Best Buy Co., Inc.(a)		112,156		9,847,297
Burlington Stores, Inc.(a)(b)		31,999		7,296,732
CarMax, Inc.(b)		80,378		7,046,739
Carvana Co.(b)		21,417		1,971,435
Dick’s Sporting Goods, Inc.(a)		32,815		1,624,014
Five Below, Inc.(b)		27,078		3,462,193
Floor & Decor Holdings, Inc., Class A(a)(b)		31,642		1,607,730
Foot Locker, Inc.(a)		55,973		2,182,387
Gap, Inc.(a)		116,136		2,053,285
Home Depot, Inc.(a)		549,721		120,048,072
L Brands, Inc.(a)		108,526		1,966,491
Lowe’s Cos., Inc.(a)		385,240		46,136,343
O’Reilly Automotive, Inc.(b)		36,876		16,161,276

Security	Shares		Value
Specialty Retail (continued)
Penske Automotive Group, Inc.(a)		15,197	$	763,193
Ross Stores, Inc.		176,455		20,542,891
Tiffany & Co.(a)		59,285		7,923,440
TJX Cos., Inc.		607,969		37,122,587
Tractor Supply Co.		59,878		5,595,000
Ulta Salon Cosmetics & Fragrance, Inc.(b)		27,601		6,986,917
Urban Outfitters, Inc.(a)(b)		31,154		865,147
Williams-Sonoma, Inc.(a)		40,386		2,965,948
				324,653,909
Technology Hardware, Storage & Peripherals — 4.7%
Apple, Inc.		2,217,286		651,106,034
Dell Technologies, Inc., Class C(a)(b)		76,696		3,941,407
Hewlett Packard Enterprise Co.(a)		646,891		10,259,691
HP, Inc.		738,818		15,182,710
NCR Corp.(b)		63,562		2,234,840
NetApp, Inc.(a)		120,882		7,524,904
Pure Storage, Inc., Class A(b)		117,353		2,007,910
Western Digital Corp.		149,534		9,490,923
Xerox Holdings Corp.(b)		87,896		3,240,726
				704,989,145
Textiles, Apparel & Luxury Goods — 0.8%
Capri Holdings Ltd.(b)		67,961		2,592,712
Carter’s, Inc.(a)		22,980		2,512,633
Columbia Sportswear Co.(a)		15,339		1,536,814
Hanesbrands, Inc.(a)		182,139		2,704,764
Lululemon Athletica, Inc.(a)(b)		58,559		13,566,364
NIKE, Inc., Class B		615,834		62,390,143
PVH Corp.(a)		37,356		3,927,983
Ralph Lauren Corp.(a)		23,530		2,758,187
Skechers U.S.A., Inc., Class A(b)		65,399		2,824,583
Tapestry, Inc.		132,547		3,574,793
Under Armour, Inc., Class A(a)(b)		88,739		1,916,762
Under Armour, Inc., Class C(a)(b)		98,963		1,898,110
VF Corp.(a)		151,970		15,145,330
				117,349,178
Thrifts & Mortgage Finance — 0.0%
LendingTree, Inc.(a)(b)		3,481		1,056,274
MGIC Investment Corp.(a)		181,135		2,566,683
New York Community Bancorp, Inc.(a)		221,693		2,664,750
TFS Financial Corp.(a)		20,191		397,359
				6,685,066
Tobacco — 0.7%
Altria Group, Inc.		935,367		46,684,167
Philip Morris International, Inc.		775,627		65,998,101
				112,682,268
Trading Companies & Distributors — 0.3%
Air Lease Corp.(a)		53,522		2,543,365
Fastenal Co.(a)		286,408		10,582,776
HD Supply Holdings, Inc.(b)		84,427		3,395,654
MSC Industrial Direct Co., Inc., Class A(a)		22,353		1,754,040
United Rentals, Inc.(b)		36,859		6,146,975
Univar Solutions, Inc.(a)(b)		83,298		2,019,144
W.W. Grainger, Inc.		21,131		7,153,266
Watsco, Inc.(a)		15,602		2,810,700
WESCO International, Inc.(a)(b)		19,814		1,176,754
				37,582,674
Transportation Infrastructure — 0.0%
Macquarie Infrastructure Corp.(a)		33,742		1,445,507
Water Utilities — 0.1%
American Water Works Co., Inc.		89,836		11,036,352
Aqua America, Inc.(a)		106,136		4,982,024
				16,018,376

SCHEDULE OF INVESTMENTS 27

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Wireless Telecommunication Services — 0.1%
Sprint Corp.(b)		276,127	$	1,438,622
T-Mobile U.S., Inc.(b)		156,822		12,297,981
Telephone & Data Systems, Inc.		52,824		1,343,314
United States Cellular Corp.(b)		6,801		246,400
				15,326,317
Total Common Stocks — 97.8% (Cost — $11,057,929,319)				14,803,221,131
Investment Companies — 0.3%
iShares Russell 1000 ETF(a)(e)		256,813		45,820,575
Total Investment Companies — 0.3% (Cost — $36,126,845)				45,820,575
Total Long-Term Investments — 98.1% (Cost — $11,094,056,164)				14,849,041,706

Security	Shares		Value
Short-Term Securities — 10.8%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.84%(c)(d)(e)		1,419,147,567	$	1,419,715,226
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.52%(c)(e)		216,786,742		216,786,742
Total Short-Term Securities — 10.8% (Cost — $1,636,221,819)				1,636,501,968
Total Investments — 108.9% (Cost — $12,730,277,983)				16,485,543,674
Liabilities in Excess of Other Assets — (8.9)%				(1,343,809,803	)
Net Assets — 100.0%			$	15,141,733,871

^(a)  Security, or a portion of the security, is on loan.

^(b)  Non-income producing security.

^(c)  Annualized7-day yield as of period end.

^(d)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(e)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares Held at 12/31/18		Shares Purchased		Shares Sold			Shares Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
BlackRock, Inc.		52,998		7,164		(1,334	)		58,828	$	29,572,836	$	729,838		$	(54,049	)	$	6,284,173
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		799,897,976		619,249,591		—			1,419,147,567		1,419,715,226		4,291,782	(c)		21,604			246,864
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		150,337,223		66,449,519		—			216,786,742		216,786,742		2,745,729			—			—
iShares Russell 1000 ETF		206,819		3,354,896		(3,304,902	)		256,813		45,820,575		1,693,906			8,067,920			9,712,045
										$	1,711,895,379	$	9,461,255		$	8,035,475		$	16,243,082

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares purchased (sold).

^(c)  Represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value / Unrealized Appreciation (Depreciation)
Long Contracts
S&P 500E-Mini Index		676		03/20/20	$	109,211	$	322,828
S&P MidCap 400E-Mini Index		44		03/20/20		9,085		19,138
							$	341,966

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Large Cap Index Master Portfolio

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statements of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts	Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	341,966	$	—	$	$	—	$	341,966

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts, if any, are reported in the Schedule of Investments. In the Statements of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in net unrealized appreciation.

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statements of Operations were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts	Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	35,649,991	$	—	$	$	—	$	35,649,991
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	101,265	$	—	$	$	—	$	101,265

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	98,098,801

For more information about the Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Long-Term Investments(a):
Common Stocks	$	14,803,221,131	$	—	$	—	$	14,803,221,131
Investment Companies		45,820,575		—		—		45,820,575
Short-Term Securities		1,636,501,968		—		—		1,636,501,968
	$	16,485,543,674	$	—	$	—	$	16,485,543,674
Derivative Financial Instruments(b)
Assets:
Equity contracts	$	341,966	$	—	$	—	$	341,966

^(a)  See above Schedule of Investments for values in each industry.

^(b)  Derivative financial instruments are futures contracts. Futures contracts which are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

SCHEDULE OF INVESTMENTS 29

Statement of Assets and Liabilities

December 31, 2019

	Large Cap Index Master Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $1,393,562,024, cost — $11,035,160,735)	$	14,773,648,295
Investments at value — affiliated (cost — $1,695,117,248)		1,711,895,379
Cash		37,431
Cash pledged for futures contracts		8,326,100
Receivables:
Investments sold		69,584,302
Securities lending income — affiliated		449,515
Contributions from investors		10,996,683
Dividends — affiliated		201,553
Dividends — unaffiliated		15,365,864
Variation margin on futures contracts		501,150
Prepaid expenses		55,835
Total assets		16,591,062,107
LIABILITIES
Cash collateral on securities loaned at value		1,419,501,248
Payables:
Investments purchased		20,783,192
Investment advisory fees		708,257
Other accrued expenses		57,505
Trustees’ fees		40,262
Withdrawals to investors		8,237,772
Total liabilities		1,449,328,236
NET ASSETS	$	15,141,733,871
NET ASSETS CONSIST OF
Investors’ capital	$	11,386,126,214
Net unrealized appreciation (depreciation)		3,755,607,657
NET ASSETS	$	15,141,733,871

See notes to financial statements.

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Operations

Year Ended December 31, 2019

	Large Cap Index Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	5,169,473
Dividends — unaffiliated		237,125,691
Securities lending income — affiliated — net		4,291,782
Foreign taxes withheld		(18,846	)
Total investment income		246,568,100
EXPENSES
Investment advisory		3,796,271
Trustees		174,825
Professional		95,716
Accounting services		40,984
Printing		1,338
Miscellaneous		133,584
Total expenses		4,242,718
Less fees waived and/or reimbursed by the Manager		(114,692	)
Total expenses after fees waived and/or reimbursed		4,128,026
Net investment income		242,440,074
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Futures contracts		35,649,991
Investments — affiliated		8,035,475
Investments — unaffiliated		(17,250,010	)
		26,435,456
Net change in unrealized appreciation (depreciation) on:
Futures contracts		101,265
Investments — affiliated		16,243,082
Investments — unaffiliated		3,115,769,725
		3,132,114,072
Net realized and unrealized gain		3,158,549,528
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	3,400,989,602

See notes to financial statements.

FINANCIAL STATEMENTS 31

Statements of Changes in Net Assets

	Large Cap Index Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	242,440,074		$	162,226,602
Net realized gain (loss)		26,435,456			(46,751,799	)
Net change in unrealized appreciation (depreciation)		3,132,114,072			(745,515,325	)
Net increase (decrease) in net assets resulting from operations		3,400,989,602			(630,040,522	)
CAPITAL TRANSACTIONS
Proceeds from contributions		2,809,050,262			7,660,435,677
Value of withdrawals		(1,348,261,152	)		(3,447,460,074	)
Net increase in net assets derived from capital transactions		1,460,789,110			4,212,975,603
NET ASSETS
Total increase in net assets		4,861,778,712			3,582,935,081
Beginning of year		10,279,955,159			6,697,020,078
End of year	$	15,141,733,871		$	10,279,955,159

See notes to financial statements.

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights

(For a share outstanding throughout each period)

	Large Cap Index Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		31.33	%		(4.81	)%		21.65	%		11.97	%		0.92	%
Ratios to Average Net Assets
Total expenses		0.03	%		0.04	%		0.04	%		0.04	%		0.05	%
Total expenses after fees waived and/or reimbursed and paid indirectly		0.03	%		0.03	%		0.04	%		0.04	%		0.04	%
Net investment income		1.92	%		1.97	%		1.92	%		2.11	%		1.93	%
Supplemental Data
Net assets, end of year (000)	$	15,141,734		$	10,279,955		$	6,697,020		$	3,967,557		$	2,542,629
Portfolio turnover rate		10	%		12	%		12	%		13	%		6	%

See notes to financial statements.

FINANCIAL HIGHLIGHTS 33

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. Large Cap Index Master Portfolio (the “Master Portfolio”) is a series of MIP. The Master Portfolio is classified as diversified.

The Master Portfolio, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, are included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the Master Portfolio is informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain.

Segregation and Collateralization: In cases where the Master Portfolio enters into certain investments (e.g., futures contracts) that would be treated as “senior securities” for 1940 Act purposes, the Master Portfolio may segregate or designate on its books and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the Master Portfolio may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, the Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. The Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Master Portfolio, which cannot be predicted with any certainty.

Other: Expenses directly related to the Master Portfolio are charged to the Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the New York Stock Exchange (“NYSE”) (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board of Trustees of the MIP (the “Board”). The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies:The following methods and inputs are used to establish the fair value of the Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that the Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Fair Value Hierarchy:Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

4. SECURITIES AND OTHER INVESTMENTS

Securities Lending: The Master Portfolio may lend its securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the Master Portfolio collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by the Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the Master Portfolio and any additional required collateral is delivered to the Master Portfolio, or excess collateral returned by the Master Portfolio, on the next business day. During the term of the loan, the Master Portfolio is entitled to all distributions made on or in respect of the loaned securities, but does not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as common stocks in the Master Portfolio’s Schedule of Investments, and the value of any related collateral are shown separately in the Statement of Assets and Liabilities as a component of investments at value — unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedule of Investments.

Securities lending transactions are entered into by the Master Portfolio under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the Master Portfolio, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and the Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the Master Portfolio’s securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
Barclays Bank Plc	$	40,633,469	$	(40,633,469	)	$	—
Barclays Capital, Inc.		14,666,761		(14,666,761	)		—
BMO Capital Markets		180,070		(180,070	)		—
BNP Paribas Prime Brokerage International Limited		419,027,911		(419,027,911	)		—
BNP Paribas Securities Corp.		3,595,077		(3,595,077	)		—
BofA Securities, Inc.		204,708,811		(204,708,811	)		—
Citadel Clearing LLC		3,635,124		(3,635,124	)		—
Credit Suisse Securities (USA) LLC		14,116,839		(14,116,839	)		—
Deutsche Bank Securities, Inc.		8,706,707		(8,706,707	)		—
Goldman Sachs & Co.		124,615,264		(124,615,264	)		—
HSBC Bank Plc		46,631,441		(46,631,441	)		—
Jefferies LLC		683,562		(683,562	)		—
JP Morgan Securities LLC		146,428,140		(146,428,140	)		—

NOTESTO FINANCIAL STATEMENTS 35

Notes to Financial Statements  (continued)

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
Morgan Stanley��& Co. LLC	$	108,028,420	$	(108,028,420	)	$	—
Nomura Securities International, Inc.		10,178,572		(10,178,572	)		—
RBC Capital Markets LLC		2,567,182		(2,567,182	)		—
Scotia Capital (USA), Inc		8,943,420		(8,943,420	)		—
SG Americas Securities LLC		26,171,758		(26,171,758	)		—
State Street Bank and Trust Co.		25,323		(25,323	)		—
TD Prime Services LLC		3,203,684		(3,203,684	)		—
UBS AG		39,726,729		(39,726,729	)		—
UBS Securities LLC		61,144,510		(61,144,510	)		—
Virtu Americas, LLC		9,028,774		(9,028,774	)		—
Wells Fargo Bank, National Association		41,525,643		(41,525,643	)		—
Wells Fargo Securities LLC		55,388,833		(55,388,833	)		—
	$	1,393,562,024	$	(1,393,562,024	)	$	—

^(a)  Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by Master Portfolio is disclosed in the Master Portfolio’s Statement of Assets and Liabilities.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the Master Portfolio benefits from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”). BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. The Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the Master Portfolio.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The Master Portfolio engages in various portfolio investment strategies using derivative contracts both to increase the returns of the Master Portfolio and/or to manage its exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedule of Investments. These contracts may be transacted on an exchange orover-the-counter (“OTC”).

Futures Contracts: Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

Futures contracts are agreements between the Master Portfolio and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the Master Portfolio is required to deposit initial margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statement of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedule of Investments and cash deposited, if any, are shown as cash pledged for futures contracts in the Statement of Assets and Liabilities. Pursuant to the contract, the Master Portfolio agrees to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statement of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statement of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory:MIP, on behalf of the Master Portfolio, entered into an Investment Advisory Agreement with the Manager, the Master Portfolio’s investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of the Master Portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Master Portfolio.

For such services, the Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.03% of the average daily value of the Master Portfolio’s net assets.

BlackRock Advisors, LLC (“BAL”) is not entitled to compensation for providing administrative services to the Master Portfolio, for so long as BAL (or an affiliate) is entitled to compensation for providing administrative services to corresponding feeder funds that invest substantially all of their assets in the Master Portfolio, or BAL (or an affiliate) receives investment advisory fees from the Master Portfolio.

Expense Limitations, Waivers, Reimbursements and Recoupments: With respect to the Master Portfolio, the Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees the Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). The amount of waivers and/or reimbursements of fees and expenses made pursuant to the expense limitation described below will be reduced by the amount of the affiliated money market fund waiver. This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the amount waived was $91,431.

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

The Manager has contractually agreed to waive its investment advisory fee with respect to any portion of the Master Portfolio’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through April 30, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees or by a vote of a majority of the outstanding voting securities of the Master Portfolio. This amount is included in fees waived and/or reimbursed by the Manager. For the year ended December 31, 2019, the Manager waived $23,261 in investment advisory fees pursuant to this arrangement.

Securities Lending:The SEC has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The Master Portfolio is responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the Master Portfolio bears to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a 90 day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, the Master Portfolio retains 73.5% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, the Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 80% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Statement of Operations. For the year ended December 31, 2019, the Master Portfolio paid BTC $1,219,910 for securities lending agent services.

Interfund Lending:In accordance with an exemptive order (the “Order”) from the SEC, the Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Master Portfolio’s investment policies and restrictions. The Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Master Portfolio are trustees and/or officers of BlackRock or its affiliates.

Other Transactions:The Master Portfolio may purchase securities from, or sell securities to, an affiliated fund provided the affiliation is due solely to having a common investment adviser, common officers, or common trustees. For the year ended December 31, 2019, the purchase and sale transactions and any net realized gains (losses) with affiliated funds in compliance with Rule17a-7 under the 1940 Act were as follows:

Purchases		Sales		Net Realized Gain (Loss)
$	371,150,750	$	95,952,350	$	(13,842,660	)

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments, excluding short-term securities were $2,716,548,589 and $1,219,977,654, respectively.

8. INCOME TAX INFORMATION

The Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

NOTESTO FINANCIAL STATEMENTS 37

Notes to Financial Statements  (continued)

Management has analyzed tax laws and regulations and their application to the Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

Tax cost	$	12,782,785,918
Gross unrealized appreciation	$	4,065,966,013
Gross unrealized depreciation		(363,208,257	)
Net unrealized appreciation	$	3,702,757,756

9. BANK BORROWINGS

MIP, on behalf of the Master Portfolio along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the Master Portfolio may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the Master Portfolio, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statement of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the Master Portfolio did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, the Master Portfolio invests in securities or other instruments and may enter into certain transactions, and such activities subject the Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. The Master Portfolio’s prospectus provides details of the risks to which the Master Portfolio is subject.

The Master Portfolio may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk:The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. The Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that the Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. The Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause the Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of the Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which the Master Portfolio invests.

Counterparty Credit Risk:The Master Portfolio may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolio manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Master Portfolio to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolio’s exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Master Portfolio.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

With exchange-traded futures, there is less counterparty credit risk to the Master Portfolio since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, the Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Master Portfolio.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolio through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm Large Cap Index Master Portfolio

To the Board of Trustees of

Master Investment Portfolio and Investors of Large Cap Index Master Portfolio

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Large Cap Index Master Portfolio (one of the series constituting Master Investment Portfolio, referred to hereafter as the “Master Portfolio”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Master Portfolio as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Master Portfolio’s management. Our responsibility is to express an opinion on the Master Portfolio’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolio in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

REPORT OF INDEPENDENT REGISTERED PUBLIC  ACCOUNTING FIRM 39

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of BlackRock Funds III and MIP, on behalf of iShares Russell 1000 Large-Cap Index Fund and Large Cap Index Master Portfolio, respectively, met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions:During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions:During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements:The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number ofBlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

TRUSTEEAND OFFICER INFORMATION 41

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number ofBlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015); President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc.,55 East 52nd Street, New York, New York 10055. (b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate. (c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015. (d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex. (e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

TRUSTEEAND OFFICER INFORMATION 43

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge by calling(800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Distributor

BlackRock Investments, LLC

New York, NY 10022

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information

General Information

Householding

The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Fund at(800) 441-7762.

Availability of Quarterly Schedule of Investments

The Fund/Master Portfolio file their complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information onForm N-Q. The Fund’s/Master Portfolio’s Forms N-PORT and N-Q are available on the SEC’s website at sec.gov. The Fund’s/Master Portfolio’s Forms N-Q may also be obtained upon request and without charge by calling(800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Fund/Master Portfolio use to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling (800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Fund/Master Portfolio voted proxies relating to securities held in the Fund’s/Master Portfolio’s portfolio during the most recent12-month period ended June 30 is available upon request and without charge (1) atblackrock.com; or by calling(800) 441-7762; and (2) on the SEC’s website at sec.gov.

BlackRock’s Mutual Fund Family

BlackRock offers a diverse lineup of open-end mutual funds crossing all investment styles and managed by experts in equity, fixed-income and tax-exempt investing. Visitblackrock.com for more information.

Shareholder Privileges

Account Information

Call us at (800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visitblackrock.com for more information.

Automatic Investment Plans

Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.

Systematic Withdrawal Plans

Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.

Retirement Plans

Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.

ADDITIONAL INFORMATION 45

Additional Information  (continued)

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding their non-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal non-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose to non-affiliated third parties anynon-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. These non-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to non-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the non-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

Glossary of Terms Used in this Report

Portfolio Abbreviations
ETF	Exchange-Traded Fund
REIT	Real Estate Investment Trust

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund’s current prospectus. Past performance results shown in this report should not be considered a representation of future performance. Investment returns and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Statements and other information herein are as dated and are subject to change.

LCI-12/19-AR

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· iShares S&P 500 Index Fund

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call (800) 441-7762 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: (i) accessing the BlackRock website at blackrock.com/edelivery and logging into your accounts, if you hold accounts directly with BlackRock, or (ii) contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summary		4
About Fund Performance		6
Disclosure of Expenses		6
Derivative Financial Instruments		6
Fund Financial Statements:
Statement of Assets and Liabilities		7
Statement of Operations		8
Statements of Changes in Net Assets		9
Fund Financial Highlights		10
Fund Notes to Financial Statements		17
Fund Report of Independent Registered Public Accounting Firm		22
Important Tax Information		22
Master Portfolio Information		23
Master Portfolio Financial Statements:
Schedule of Investments		24
Statement of Assets and Liabilities		31
Statement of Operations		32
Statements of Changes in Net Assets		33
Master Portfolio Financial Highlights		34
Master Portfolio Notes to Financial Statements		35
Master Portfolio Report of Independent Registered Public Accounting Firm		41
Statement Regarding Liquidity Risk Management Program		42
Trustees and Officer Information		43
Additional Information		47

3

Fund Summary  as of December 31, 2019 iShares S&P 500 Index Fund

Investment Objective

iShares S&P 500 Index Fund’s (the “Fund”) investment objective is to seek to provide investment results that correspond to the total return performance of publicly-traded common stocks in the aggregate, as represented by the Standard & Poor’s 500^® Index (“S&P 500^® Index”).

Portfolio Management Commentary

How did the Fund perform?

For the 12-month period ended December 31, 2019, the Fund’s Institutional Shares returned 31.35%, Service Shares returned 31.20%, Investor A Shares returned 31.02%, Investor C1 Shares returned 30.13%, Class G Shares returned 31.45%, Class K Shares returned 31.44%, and Investor P Shares returned 31.02%. The benchmark S&P 500^® Index returned 31.49% for the same period.

Returns for the Fund’s respective share classes differ from the benchmark index based on individual share-class expenses. The Fund invests all of its assets in S&P 500 Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio.

Describe the market environment.

All eleven of the Global Industry Classification Standard (“GICS”) sectors advanced in the first quarter of 2019 as positive headlines regarding Sino-American trade negotiations, relatively strong corporate earnings growth, and the Fed’s dovish pivot helped investor sentiment recover from steep losses in the fourth quarter of 2018. The technology sector outperformed and was responsible for 29% of the S&P 500^® Index’s overall rally. Real estate was the second best-performing sector as a decline in interest rates throughout the quarter drove demand for bond proxies. Health care shares underperformed as political risks weighed on sentiment, but still posted a respectable gain.

In its January 2019 announcement, the Fed indicated that it would refrain from interest rate hikes for the foreseeable future, with a dovish assessment of U.S. economic conditions and transparency around balance sheet normalization. This reduced market-based expectations of interest rate hikes, serving as a boon for both equities and bonds. Less optimism was evident in the U.S. rates market. The pause in interest rate hiking by the Fed coupled with lowered forecasts for growth drove investors into longer-duration government bonds.

The prospect of an easier monetary policy buoyed equities broadly in the second quarter of 2019. At the June Federal Open Market Committee announcement, Fed Chair Jerome Powell noted that should trade tensions weigh on the committee’s economic outlook or should the shortfall of inflation from the target rate persist longer than expected, the Fed would provide more accommodation to sustain the expansion.

Trade tensions were a source of intra-quarter volatility. In May, President Trump threatened an increase in tariffs and protectionism against both China and Mexico. The S&P 500^® Index fell 6.4% in May on these renewed trade concerns. However, these announcements did not materialize, and sentiment eased by June month end.

Looking to interest rates, the 10-year U.S. Treasury yield declined 0.50% in the second quarter to 2% — the lowest level since 2016. The yield curve remained a source of uncertainty as the three-month/10-year Treasury spread remained in negative territory while the five-year/30-year Treasury spread expanded throughout the quarter.

In the third quarter of 2019, trade tensions were a key focus for both domestic and global investors. The S&P 500^® Index suffered its worst week of 2019 in early August on the back of President Trump’s promise to impose 10% tariffs on all Chinese imports that were not already subject to 25% tariffs. U.S.-China tensions did ostensibly ease ahead of a new round of trade talks in October. In monetary policy, the Fed lowered the target range for the federal funds rates at both its July and September meetings.

On the macroeconomic front, survey-based U.S. economic indicators continued to soften in the manufacturing and consumer sectors, while hard economic data releases exhibited resilience. In interest rates, the frequently monitored two-year/ten-year Treasury yield spread inverted for the first time since the global financial crisis in August but ended the quarter in positive territory.

In the fourth quarter of 2019, risk appetite was boosted broadly by expectations of a U.S.-China trade deal, strong economic growth, and easy monetary policy. U.S. tariffs on China were originally scheduled to increase on December 15 but were avoided due to persistent negotiations between the United States and China. Additionally, news that the United States did not impose tariffs on European Union auto exports helped support sentiment. On the macroeconomic front, the U.S. services and employment sectors remained buoyant.

In November, 266,000 jobs were added to the economy, revising the third quarter unemployment rate down to 3.5% from 3.7%. Overall, the supportive macroeconomic data and boosted risk appetite drove selling of Treasuries in the quarter. Despite the strength in the U.S. economy, the Fed cut the benchmark federal funds rate to 1.75% in October, marking the third rate cut of the year.

For the year 2019, all the GICS sectors returned positive results in the S&P 500^® Index. Top contributors were information technology (50.3%), communication services (32.6%), and financials (32.1%). Bottom contributors for the year were energy (11.8%), health care (20.8%), and materials (24.8%).

Describe recent portfolio activity.

During the period, as changes were made to the composition of the S&P 500^® Index, the Master Portfolio purchased and sold securities to pursue its objective of seeking to replicate the total return of the benchmark index.

Describe portfolio positioning at period end.

The Master Portfolio remains positioned to match the risk characteristics of its benchmark index, irrespective of the market’s future direction.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) iShares S&P 500 Index Fund

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming transaction costs and other operating expenses, including administration fees, if any.

^(b)  The Fund invests all of its assets in the Master Portfolio. Under normal circumstances, the Master Portfolio invests at least 90% of the value of the Fund’s assets, plus the amount of any borrowing for investment purposes, in securities comprised of the S&P 500^® Index.

^(c)  An unmanaged index that covers 500 leading companies and captures approximately 80% coverage of available market capitalization.

Performance Summary for the Period Ended December 31, 2019

				Average Annual Total Returns (a)
				1 Year						5 Years						10 Years
	6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		10.87	%		31.35	%		N/A			11.58	%		N/A			13.40	%		N/A
Service		10.80			31.20			N/A			11.45			N/A			13.26			N/A
Investor A		10.72			31.02			N/A			11.31			N/A			13.11			N/A
Investor C1		10.36			30.13			N/A			10.51			N/A			12.30			N/A
Class G		10.92			31.45			N/A			11.67			N/A			13.48			N/A
Class K		10.91			31.44			N/A			11.66			N/A			13.47			N/A
Investor P		10.73			31.02			24.14	%		11.31			10.11	%		13.12			12.51	%
S&P 500® Index		10.92			31.49			N/A			11.70			N/A			13.56			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distribution and service fees. See “About Fund Performance” on page 6 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

Expense Example

	Actual						Hypothetical (b)
	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
Institutional	$	1,000.00	$	1,108.70	$	0.53	$	1,000.00	$	1,024.70	$	0.51		0.10	%
Service		1,000.00		1,108.00		1.17		1,000.00		1,024.10		1.12		0.22
Investor A		1,000.00		1,107.20		1.86		1,000.00		1,023.44		1.79		0.35
Investor C1		1,000.00		1,103.60		5.30		1,000.00		1,025.16		5.09		1.00
Class G		1,000.00		1,109.20		0.05		1,000.00		1,020.16		0.05		0.01
Class K		1,000.00		1,109.10		0.16		1,000.00		1,025.05		0.15		0.03
Investor P		1,000.00		1,107.30		1.86		1,000.00		1,023.44		1.79		0.35

^(a)  For each class of the Fund, expenses are equal to the annualized expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period shown). Because the Fund invests all of its assets in the Master Portfolio, the expense example reflects the net expenses of both the Fund and the Master Portfolio in which it invests.

^(b)  Hypothetical 5% annual return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

See “Disclosure of Expenses” on page 6 for further information on how expenses were calculated.

FUND SUMMARY 5

About Fund Performance

Institutional and Class K Sharesare not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors. Prior to April 11, 2013, Class K Shares were an undesignated share class of the Fund. Institutional Shares performance shown prior to the Institutional Shares inception date of April 10, 2013 is that of Class K Shares (which have no distribution or service fees) and was restated to reflect Institutional Shares fees.

Service Sharesare not subject to any sales charge. These shares are subject to a service fee of 0.15% per year (but no distribution fee) and are available only to certain eligible investors. Service Shares performance shown prior to the Service Shares inception date of April 19, 2013 is that of Class K Shares (which have no distribution or service fees) and was restated to reflect Service Shares fees.

Investor A Sharesare not subject to any sales charge and bear no ongoing distribution fee. These shares are subject to an ongoing service fee of 0.25% per year. These shares are generally available through financial intermediaries. Investor A Shares performance shown prior to the Investor A Shares inception date of April 10, 2013 is that of Class K Shares (which have no distribution or service fees) and was restated to reflect Investor A Shares fees.

Investor C1 Sharesare not subject to any sales charge. These shares are subject to a distribution fee of 0.75% per year and a service fee of 0.15% per year. These shares are only available for dividend and capital gain reinvestment by existing shareholders and for purchase by certain employer-sponsored retirement plans. These shares automatically convert to Investor A Shares after approximately ten years. On November 12-13, 2019, the Board of Trustees of the Trust approved the conversion of all issued and outstanding Investor C1 Shares into Investor A Shares, which will be effective on or about the close of business on February 24, 2020. Investor C1 Shares performance shown prior to the Investor C1 Shares inception date of April 19, 2013 is that of Class K Shares (which have no distribution or service fees) and was restated to reflect Investor C1 Shares fees.

Class G Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to investors on eligible platforms. Class G Shares performance shown prior to the Class G Shares inception date of July 1, 2019 is that of Class K Shares (which have no distribution or service fees).

Investor P Shares are subject to a maximum initial sales charge (front-end load) of 5.25% and a service fee of 0.25% per year (but no distribution fee). These shares are only available to investors purchasing shares through registered representatives of an insurance company’s broker-dealer that has entered into an agreement with the Fund’s distributor to offer such shares. Investor P Shares performance shown prior to the Investor P Shares inception date of August 6, 2018 is that of Class K Shares (which have no distribution or service fees) and was restated to reflect Investor P Shares fees.

Performance information reflects past performance and does not guarantee future results. Current performance may be lower or higher than the performance data quoted. Refer toblackrock.comto obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Figures shown in the performance table on the previous page assume reinvestment of all distributions, if any, at net asset value on theex-dividend date. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of administration, service and distribution fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (“BAL” or the “Administrator”), the Fund’s administrator, has contractually agreed to waive and/or reimburse a portion of the Fund’s expenses. Without such waiver and/or reimbursement, the Fund’s performance would have been lower. With respect to the Fund’s contractual waiver, the Administrator is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See Note 4 of the Notes to Financial Statements for additional information on waivers and/or reimbursements.

Disclosure of Expenses

Shareholders of the Fund may incur the following charges: (a) transactional expenses, such as sales charges; and (b) operating expenses, including administration fees, service and distribution fees, including12b-1 fees, acquired fund fees and expenses, and other fund expenses. The expense example on the previous page (which is based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019) is intended to assist shareholders both in calculating expenses based on an investment in the Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense example provides information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their share class under the heading entitled “Expenses Paid During the Period.”

The expense example also provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in the Fund and other funds, compare the 5% hypothetical example with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense example are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical example is useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

Derivative Financial Instruments

The Master Portfolio may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The Master Portfolio’s successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation the Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The Master Portfolio’s investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	iShares S&P 500 Index Fund
ASSETS
Investments at value — Master Portfolio	$	22,504,337,767
Receivables:
Capital shares sold		80,340,197
Withdrawals from the Master Portfolio		16,580,489
Total assets		22,601,258,453
LIABILITIES
Payables:
Administration fees		1,498,559
Capital shares redeemed		96,920,686
Professional fees		12,200
Service and distribution fees		873,571
Total liabilities		99,305,016
NET ASSETS	$	22,501,953,437
NET ASSETS CONSIST OF
Paid-in capital	$	13,811,060,308
Accumulated earnings		8,690,893,129
NET ASSETS	$	22,501,953,437
NET ASSET VALUE
Institutional —Based on net assets of $3,950,956,340 and 10,325,832 shares outstanding, unlimited number authorized, no par value	$	382.63
Service — Based on net assets of $334,402,081 and 874,022 shares outstanding, unlimited number authorized, no par value	$	382.60
Investor A — Based on net assets of $2,667,724,492 and 6,974,080 shares outstanding, unlimited number authorized, no par value	$	382.52
Investor C1 — Based on net assets of $2,615,015 and 6,810 shares outstanding, unlimited number authorized, no par value	$	383.97
Class G — Based on net assets of $5,796,330,770 and 15,145,597 shares outstanding, unlimited number authorized, no par value	$	382.71
Class K — Based on net assets of $8,471,585,299 and 22,135,444 shares outstanding, unlimited number authorized, no par value	$	382.72
Investor P — Based on net assets of $1,278,339,440 and 3,344,515 shares outstanding, unlimited number authorized, no par value	$	382.22

See notes to financial statements.

FINANCIAL STATEMENTS 7

Statement of Operations

Year Ended December 31, 2019

	iShares S&P 500 Index Fund
INVESTMENT INCOME
Net investment income allocated from the Master Portfolio:
Dividends — affiliated	$	6,828,890
Dividends — unaffiliated		379,002,077
Securities lending income — affiliated — net		656,943
Foreign taxes withheld		(1,465,581	)
Expenses		(5,069,233	)
Fees waived		545,290
Total investment income		380,498,386
FUND EXPENSES
Service and distribution — class specific		9,784,335
Administration — class specific		7,168,096
Professional		12,189
Miscellaneous		450
Total expenses		16,965,070
Less fees waived and/or reimbursed by the Manager		(12,189	)
Total expenses after fees waived and/or reimbursed		16,952,881
Net investment income		363,545,505
REALIZED AND UNREALIZED GAIN (LOSS) ALLOCATED FROM THE MASTER PORTFOLIO
Net realized gain (loss) from:
Futures contracts		65,399,174
Investments		(25,685,927	)
		39,713,247
Net change in unrealized appreciation (depreciation) on:
Futures contracts		1,879,492
Investments		4,820,983,169
		4,822,862,661
Net realized and unrealized gain		4,862,575,908
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	5,226,121,413

See notes to financial statements.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	iShares S&P 500 Index Fund
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	363,545,505		$	281,155,486
Net realized gain		39,713,247			46,754,993
Net change in unrealized appreciation (depreciation)		4,822,862,661			(1,241,188,390	)
Net increase (decrease) in net assets resulting from operations		5,226,121,413			(913,277,911	)
DISTRIBUTIONS(a)
Institutional		(80,052,439	)		(80,048,879	)
Service		(6,647,327	)		(7,456,614	)
Investor A		(46,633,679	)		(46,008,669	)
Investor C1		(29,188	)		(285,719	)
Class G		(60,325,171	)		—
Class K		(199,316,804	)		(212,831,963	)
Investor P		(22,025,637	)		(9,203,819	)
Decrease in net assets resulting from distributions to shareholders		(415,030,245	)		(355,835,663	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		1,109,955,590			5,000,372,689
NET ASSETS
Total increase in net assets		5,921,046,758			3,731,259,115
Beginning of year		16,580,906,679			12,849,647,564
End of year	$	22,501,953,437		$	16,580,906,679

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 9

Financial Highlights

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	297.40		$	318.31		$	267.04		$	244.52		$	247.36
Net investment income(a)		6.46			6.03			5.42			5.13			4.79
Net realized and unrealized gain (loss)		86.13			(19.72	)		52.02			23.55			(1.71	)
Net increase (decrease) from investment operations		92.59			(13.69	)		57.44			28.68			3.08
Distributions(b)
From net investment income		(7.36	)		(5.82	)		(5.32	)		(5.08	)		(4.77	)
From net realized gain		—			(1.40	)		(0.85	)		(1.08	)		(1.15	)
Total distributions		(7.36	)		(7.22	)		(6.17	)		(6.16	)		(5.92	)
Net asset value, end of year	$	382.63		$	297.40		$	318.31		$	267.04		$	244.52
Total Return(c)
Based on net asset value		31.35	%		(4.45	)%		21.68	%		11.84	%		1.28	%
Ratios to Average Net Assets(d)
Total expenses		0.10	%(e)		0.11	%(e)		0.11	%(e)		0.11	%(e)		0.11	%(f)
Total expenses after fees waived and/or reimbursed		0.10	%(e)		0.11	%(e)		0.11	%(e)		0.11	%(e)		0.11	%(f)
Net investment income		1.87	%(e)		1.84	%(e)		1.86	%(e)		2.04	%(e)		1.93	%(f)
Supplemental Data
Net assets, end of year (000)	$	3,950,956		$	3,660,724		$	3,596,342		$	4,290,475		$	3,247,607
Portfolio turnover rate of the Master Portfolio		3	%		12	%		11	%		4	%		2	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund (continued)
	Service
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	297.38		$	318.29		$	267.02		$	244.52		$	247.35
Net investment income(a)		6.06			5.64			5.08			4.80			4.48
Net realized and unrealized gain (loss)		86.10			(19.73	)		52.00			23.56			(1.69	)
Net increase (decrease) from investment operations		92.16			(14.09	)		57.08			28.36			2.79
Distributions(b)
From net investment income		(6.94	)		(5.42	)		(4.96	)		(4.78	)		(4.47	)
From net realized gain		—			(1.40	)		(0.85	)		(1.08	)		(1.15	)
Total distributions		(6.94	)		(6.82	)		(5.81	)		(5.86	)		(5.62	)
Net asset value, end of year	$	382.60		$	297.38		$	318.29		$	267.02		$	244.52
Total Return(c)
Based on net asset value		31.20	%		(4.57	)%		21.54	%		11.71	%		1.16	%
Ratios to Average Net Assets(d)
Total expenses		0.22	%(e)		0.23	%(e)		0.23	%(e)		0.23	%(e)		0.23	%(f)
Total expenses after fees waived and/or reimbursed		0.22	%(e)		0.23	%(e)		0.23	%(e)		0.23	%(e)		0.23	%(f)
Net investment income		1.75	%(e)		1.72	%(e)		1.74	%(e)		1.91	%(e)		1.81	%(f)
Supplemental Data
Net assets, end of year (000)	$	334,402		$	318,651		$	319,504		$	332,292		$	304,088
Portfolio turnover rate of the Master Portfolio		3	%		12	%		11	%		4	%		2	%

^(a) Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 11

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund (continued)
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	297.33		$	318.23		$	266.99		$	244.52		$	247.35
Net investment income(a)		5.61			5.22			4.71			4.49			4.16
Net realized and unrealized gain (loss)		86.07			(19.72	)		51.97			23.53			(1.69	)
Net increase (decrease) from investment operations		91.68			(14.50	)		56.68			28.02			2.47
Distributions(b)
From net investment income		(6.49	)		(5.00	)		(4.59	)		(4.47	)		(4.15	)
From net realized gain		—			(1.40	)		(0.85	)		(1.08	)		(1.15	)
Total distributions		(6.49	)		(6.40	)		(5.44	)		(5.55	)		(5.30	)
Net asset value, end of year	$	382.52		$	297.33		$	318.23		$	266.99		$	244.52
Total Return(c)
Based on net asset value		31.02	%		(4.68	)%		21.38	%		11.56	%		1.03	%
Ratios to Average Net Assets(d)
Total expenses		0.35	%(e)		0.36	%(e)		0.36	%(e)		0.36	%(e)		0.36	%(f)
Total expenses after fees waived and/or reimbursed		0.35	%(e)		0.36	%(e)		0.36	%(e)		0.36	%(e)		0.36	%(f)
Net investment income		1.62	%(e)		1.60	%(e)		1.61	%(e)		1.79	%(e)		1.68	%(f)
Supplemental Data
Net assets, end of year (000)	$	2,667,724		$	2,160,098		$	2,271,969		$	1,774,331		$	1,281,538
Portfolio turnover rate of the Master Portfolio		3	%		12	%		11	%		4	%		2	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(f) Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund (continued)
	Investor C1
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	298.47		$	318.74		$	267.07		$	244.59		$	247.36
Net investment income(a)		3.25			2.70			2.58			2.68			2.36
Net realized and unrealized gain (loss)		86.35			(19.69	)		52.01			23.49			(1.65	)
Net increase (decrease) from investment operations		89.60			(16.99	)		54.59			26.17			0.71
Distributions(b)
From net investment income		(4.10	)		(1.88	)		(2.07	)		(2.61	)		(2.33	)
From net realized gain		—			(1.40	)		(0.85	)		(1.08	)		(1.15	)
Total distributions		(4.10	)		(3.28	)		(2.92	)		(3.69	)		(3.48	)
Net asset value, end of year	$	383.97		$	298.47		$	318.74		$	267.07		$	244.59
Total Return(c)
Based on net asset value		30.13	%		(5.40	)%		20.51	%		10.76	%		0.30	%
Ratios to Average Net Assets(d)
Total expenses		1.04	%(e)		1.08	%(e)		1.08	%(e)		1.08	%(e)		1.08	%(f)
Total expenses after fees waived and/or reimbursed		1.04	%(e)		1.08	%(e)		1.08	%(e)		1.08	%(e)		1.08	%(f)
Net investment income		0.94	%(e)		0.82	%(e)		0.89	%(e)		1.07	%(e)		0.95	%(f)
Supplemental Data
Net assets, end of year (000)	$	2,615		$	2,238		$	43,611		$	74,259		$	74,558
Portfolio turnover rate of the Master Portfolio		3	%		12	%		11	%		4	%		2	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions

^(d)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 13

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund (continued)
	Class G
	Period from 07/01/19(a) to 12/31/19
Net asset value, beginning of period	$	351.81
Net investment income(b)		3.41
Net realized and unrealized gain		31.80
Net increase from investment operations		35.21
Distributions from net investment income(c)		(4.31	)
Net asset value, end of period	$	382.71
Total Return(d)
Based on net asset value		10.07	%(e)
Ratios to Average Net Assets(f)
Total expenses		0.01	%(g)(h)
Total expenses after fees waived and/or reimbursed		0.01	%(g)(h)
Net investment income		1.89	%(g)(h)
Supplemental Data
Net assets, end of period (000)	$	5,796,331
Portfolio turnover rate of the Master Portfolio		3	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Aggregate total return.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(g)  Annualized.

^(h)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

See notes to financial statements.

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund (continued)
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	297.46		$	318.37		$	267.08		$	244.56		$	247.39
Net investment income(a)		6.74			6.29			5.69			5.32			4.97
Net realized and unrealized gain (loss)		86.12			(19.76	)		51.97			23.53			(1.72	)
Net increase (decrease) from investment operations		92.86			(13.47	)		57.66			28.85			3.25
Distributions(b)
From net investment income		(7.60	)		(6.04	)		(5.52	)		(5.25	)		(4.93	)
From net realized gain		—			(1.40	)		(0.85	)		(1.08	)		(1.15	)
Total distributions		(7.60	)		(7.44	)		(6.37	)		(6.33	)		(6.08	)
Net asset value, end of year	$	382.72		$	297.46		$	318.37		$	267.08		$	244.56
Total Return(c)
Based on net asset value		31.44	%		(4.38	)%		21.77	%		11.92	%		1.35	%
Ratios to Average Net Assets(d)
Total expenses		0.03	%(e)		0.04	%(e)		0.04	%(e)		0.04	%(e)		0.04	%(f)
Total expenses after fees waived and/or reimbursed		0.03	%(e)		0.04	%(e)		0.04	%(e)		0.04	%(e)		0.04	%(f)
Net investment income		1.96	%(e)		1.92	%(e)		1.93	%(e)		2.11	%(e)		2.00	%(f)
Supplemental Data
Net assets, end of year (000)	$	8,471,585		$	9,375,051		$	6,618,222		$	2,347,455		$	1,145,165
Portfolio turnover rate of the Master Portfolio		3	%		12	%		11	%		4	%		2	%

^(a) Based on average shares outstanding.

^(b) Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Where applicable, assumes the reinvestment of distributions.

^(d)  Includes the Fund’s share of the Master Portfolio’s allocated net expenses and/or net investment income.

^(e)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

See notes to financial statements.

FINANCIAL HIGHLIGHTS 15

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares S&P 500 Index Fund (continued)
	Investor P
	Year Ended December 31, 2019			Period from 08/06/18(a) to 12/31/18
Net asset value, beginning of period	$	297.10		$	339.48
Net investment income(b)		5.61			2.20
Net realized and unrealized gain (loss)		86.00			(40.58	)
Net increase (decrease) from investment operations		91.61			(38.38	)
Distributions(c)
From net investment income		(6.49	)		(2.89	)
From net realized gain		—			(1.11	)
Total distributions		(6.49	)		(4.00	)
Net asset value, end of period	$	382.22		$	297.10
Total Return(d)
Based on net asset value		31.02	%		(11.38	)%(e)
Ratios to Average Net Assets(f)
Total expenses		0.35	%(g)		0.35	%(g)(h)
Total expenses after fees waived and/or reimbursed		0.35	%(g)		0.35	%(g)(h)
Net investment income		1.62	%(g)		1.68	%(g)(h)
Supplemental Data
Net assets, end of period (000)	$	1,278,339		$	1,064,145
Portfolio turnover rate of the Master Portfolio		3	%		12	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions

^(e)  Aggregate total return.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(g)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(h)  Annualized.

See notes to financial statements.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. iShares S&P 500 Index Fund (the “Fund”) is a series of the Trust. The Fund is classified as diversified.

The Fund seeks to achieve its investment objective by investing all of its assets in S&P 500 Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio (“MIP”). MIP is an affiliate of the Trust, which has the same investment objective and strategies as the Fund. The value of the Fund’s investment in the Master Portfolio reflects the Fund’s proportionate interest in the net assets of the Master Portfolio. The performance of the Fund is directly affected by the performance of the Master Portfolio. At December 31, 2019, the percentage of the Master Portfolio owned by the Fund was 97.0%. The financial statements of the Master Portfolio, including the Schedule of Investments, are included elsewhere in this report and should be read in conjunction with the Fund’s financial statements.

The Fund offers multiple classes of shares. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that Service, Investor A, Investor C1 and Investor P Shares bear expenses related to shareholder servicing of such shares, and Investor C1 Shares also bear certain expenses related to the distribution of such shares. Institutional, Service and Class K Shares are sold only to certain eligible investors. Class G Shares are available only to investors on eligible platforms. Investor A Shares are generally available through financial intermediaries. Investor C1 Shares are only available for dividend and capital gain reinvestment by existing shareholders, and for purchase by certain employer-sponsored retirement plans. Investor P Shares are only available through registered representatives of an insurance company’s broker-dealer that has entered into an agreement with the Fund’s distributor to offer such shares. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures (except that Investor C1 shareholders may vote on material changes to the Investor A distribution and service plan). The Board of Trustees of the Trust and Board of Trustees of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

Share Class	Initial Sales Charge	CDSC	Conversion Privilege
Institutional, Service and Class K Shares	No	No		None
Investor A Shares	No	No		None
Investor C1 Shares	No	No		To Investor A Shares after approximately 10 years	(a)
Class G Shares(b)	No	No		None
Investor P Shares	Yes	No		None

^(a)  Effective on or about the close of business on February 24, 2020, all issued and outstanding Investor C1 shares will be converted into Investor A shares.

^(b)  Class G Shares commenced operations on July 1, 2019.

The Fund together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

Prior Year Reorganization: The Board and shareholders of the Fund and the Board of State Farm Mutual Fund Trust and shareholders of State Farm S&P 500 Index Fund (the “Target Fund”) approved the reorganization of the Target Fund into the Fund. As a result, the Fund acquired substantially all of the assets and assumed substantially all of the liabilities of the Target Fund in exchange for an equal aggregate value of newly-issued common shares of the Fund.

Each shareholder of the Target Fund received shares of the Fund in an amount equal to the aggregate net asset value (“NAV”) of such shareholder’s Target Fund

common shares, as determined at the close of business on November 16, 2018.

On November 16, 2018, all of the portfolio securities previously held by the Target Fund were subsequently contributed by the Fund to the Master Portfolio in exchange for an investment in the Master Portfolio.

The reorganization was accomplished by atax-free exchange of shares of the Fund in the following amounts and at the following conversion ratio:

Target Fund’s Share Class	Shares Prior to Reorganization	Conversion Ratio	Fund’s Share Class	Shares of the Fund
Premier	945,941	0.05913686	Investor A	55,940
Premier	33,672,747	0.05915653	Investor P	1,991,963
Legacy B	59,477	0.05996906	Investor A	3,567
Legacy B	388,175	0.05998901	Investor P	23,286
Class A	1,599,816	0.05876672	Investor A	94,016
Class A	24,662,964	0.05878626	Investor P	1,449,843
Class B	22,457	0.05931427	Investor A	1,332
Class B	322,358	0.05933400	Investor P	19,127
Institutional	13,145,571	0.05930584	Institutional	779,609
Class R1	411,361	0.05908879	Investor P	24,307
Class R2	1,475,390	0.05869339	Investor P	86,596
Class R3	272,729	0.05916651	Institutional	16,136

NOTESTO FINANCIAL STATEMENTS 17

Notes to Financial Statements  (continued)

The Target Fund’s net assets and composition of net assets on November 16, 2018, the valuation date of the reorganization were as follows:

	Target Fund
Net assets	$	1,483,308,771
Paid-in-capital		736,125,732
Accumulated earnings		747,183,039

For financial reporting purposes, assets received and shares issued by the Fund were recorded at fair value. However, the cost basis of the investments received from the Target Fund was carried forward by the Master Portfolio to align ongoing reporting of the Fund’s realized and unrealized gains and losses with amounts distributable to shareholders for tax purposes.

The net assets of the Fund before the acquisition were $16,246,612,781. The aggregate net assets of the Fund immediately after the acquisition amounted to $17,729,921,552. The Target Fund’s fair value and cost of investments prior to the reorganization were as follows:

Target Fund	Fair Value of Investments		Cost of Investments
State Farm S&P 500 Index Fund	$	1,473,476,973	$	726,300,157

The purpose of the transaction was to combine the assets of the Target Fund with the assets of the Fund. The reorganization was atax-free event and was effective on November 19, 2018.

Assuming the acquisition had been completed on January 1, 2018, the beginning of the fiscal reporting period of the Fund, the pro forma results of operations for the year ended December 31, 2018, are as follows:

• Net investment income: $304,743,581

• Net realized and change in unrealized loss on investments: $(1,178,955,794)

• Net decrease in net assets resulting from operations: $(874,212,213)

Because the combined investment portfolios have been managed as a single integrated portfolio since the acquisition was completed, it is not practicable to separate the amounts of revenue and earnings of the Fund that have been included in the Fund’s Statement of Operations since November 19, 2018.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from the Master Portfolio are accounted for on a trade date basis. The Fund records its proportionate share of the Master Portfolio’s income, expenses and realized and unrealized gains and losses on a daily basis. Realized and unrealized gains and losses are adjusted utilizing partnership tax allocation rules. In addition, the Fund accrues its own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions paid by the Fund are recorded on theex-dividend date. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

Indemnifications:In the normal course of business, the Fund enters into contracts that contain a variety of representations that provide general indemnification. The Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to the Fund or its classes are charged to the Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by BlackRock Advisors, LLC (“BAL” or the “Administrator”), are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the Fund and other shared expenses prorated to the Fund are allocated daily to each class based on its relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Fund’s policy is to value its financial instruments at fair value. The Fund records its investment in the Master Portfolio at fair value based on the Fund’s proportionate interest in the net assets of the Master Portfolio. Valuation of securities held by the Master Portfolio is discussed in Note 3 of the Master Portfolio’s Notes to Financial Statements, which are included elsewhere in this report.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration:The Trust, on behalf of the Fund, entered into an Administration Agreement with BAL, which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the Fund’s ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Fund. BAL is entitled to receive for these administrative services an annual fee based on the average daily net assets of the Fund as follows:

	Institutional			Service			Investor A			Investor C1			Class G			Class K			Investor P
Rate		0.09	%		0.06	%		0.09	%		0.09	%		0.0025	%		0.02	%		0.09	%

Prior to July 01, 2019, the annual rates as a percentage of average daily net assets, for the Fund were as follows:

	Institutional			Service			Investor A			Investor C1			Class K			Investor P
Rate		0.07	%		0.04	%		0.07	%		0.14	%		0.00	%		0.07	%

From time to time, BAL may waive such fees in whole or in part. Any such waiver will reduce the expenses of the Fund and, accordingly, have a favorable impact on its performance. BAL may delegate certain of its administration duties tosub-administrators.

For the year ended December 31, 2019, the following table shows the class specific administration fees borne directly by each share class of the Fund:

Institutional		Service		Investor A		Investor C1		Class G		Class K		Investor P		Total
$	3,091,691	$	168,570	$	2,020,898	$	2,868	$	47,353	$	882,876	$	953,840	$	7,168,096

Service and Distribution Fees:The Trust, on behalf of the Fund, entered into a Distribution Agreement and a Distribution and Service Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Pursuant to the Distribution and Service Plan and in accordance with Rule12b-1 under the 1940 Act, the Fund pays BRIL ongoing service and distribution fees. The fees are accrued daily and paid monthly at annual rates based upon the average daily net assets of the relevant share class of the Fund as follows:

	Service			Investor A			Investor C1			Investor P
Service Fee		0.15	%		0.25	%		0.15	%		0.25	%
Distribution Fee		—			—			0.75			—

BRIL and broker-dealers, pursuant tosub-agreements with BRIL, provide shareholder servicing and distribution services to the Fund. The ongoing service and/or distribution fee compensates/reimburses BRIL and each broker-dealer for providing shareholder servicing and/or distribution related services to shareholders.

For the year ended December 31, 2019, the following table shows the class specific service and distribution fees borne directly by each share class of the Fund:

Service		Investor A		Investor C1		Investor P		Total
$	506,108	$	6,285,475	$	22,553	$	2,970,199	$	9,784,335

Other Fees:For the year ended December 31, 2019, affiliates earned underwriting discounts, direct commissions and dealer concessions on sales of the Trust’s Investor P Shares, which totaled $83,796.

Expense Waivers and Reimbursements:The fees and expenses of the Trust’s trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Fund’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Fund. Each of BFA and BAL, as applicable, has contractually agreed to reimburse the Fund or provide an offsetting credit against the administration fees paid by the Fund in an amount equal to these independent expenses through April 30, 2021. For the year ended December 31, 2019, the amount waived was $12,189.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), the Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Fund’s investment policies and restrictions. The Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Fund did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock or its affiliates.

NOTESTO FINANCIAL STATEMENTS 19

Notes to Financial Statements  (continued)

5. INCOME TAX INFORMATION

It is the Fund’s policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

The Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Fund as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Fund’s financial statements.

The tax character of distributions paid was as follows:

	12/31/19		12/31/18
Ordinary income	$	415,030,245	$	299,133,782
Long-term capital gains		—		56,701,881
	$	415,030,245	$	355,835,663

As of period end, the tax components of accumulated net earnings were as follows:

Undistributed ordinary income	$	8,724,642
Undistributed long-term capital gains		24,679,900
Capital loss carryforwards		—
Net unrealized gains (losses)(a)		8,657,488,587
	$	8,690,893,129

^(a)  The difference between book-basis andtax-basis net unrealized gains (losses) was attributable primarily to the timing and recognition of partnership income.

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended December 31, 2019						Year Ended December 31, 2018
	Shares			Amount			Shares			Amount
Institutional
Shares sold		3,223,244		$	1,104,433,015			5,441,283		$	1,756,690,463
Shares issued in reinvestment of distributions		220,615			78,052,535			243,283			77,875,113
Shares issued in reorganization		—			—			795,745			259,853,359
Shares redeemed		(5,427,226	)		(1,853,297,343	)		(5,469,279	)		(1,776,447,671	)
Net increase (decrease)		(1,983,367	)	$	(670,811,793	)		1,011,032		$	317,971,264
Service
Shares sold		212,558		$	72,901,799			360,243		$	117,582,960
Shares issued in reinvestment of distributions		18,054			6,382,743			22,984			7,364,222
Shares redeemed		(428,101	)		(147,524,042	)		(315,533	)		(102,661,967	)
Net increase (decrease)		(197,489	)	$	(68,239,500	)		67,694		$	22,285,215
	Year Ended December 31, 2019						Year Ended December 31, 2018
Investor A
Shares sold and automatic conversion of shares		2,971,948		$	1,011,559,996			3,365,228		$	1,102,301,834
Shares issued in reinvestment of distributions		127,334			45,112,382			139,032			44,491,277
Shares issued in reorganization		—			—			154,855			50,538,536
Shares redeemed		(3,390,182	)		(1,164,300,953	)		(3,533,444	)		(1,141,702,406	)
Net increase (decrease)		(290,900	)	$	(107,628,575	)		125,671		$	55,629,241

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

	Year Ended December 31, 2019						Year Ended December 31, 2018
	Shares			Amount			Shares			Amount
Investor C1
Shares sold		15		$	5,682			—		$	—
Shares issued in reinvestment of distributions		59			21,074			866			283,335
Shares redeemed and automatic conversion of shares		(761	)		(268,842	)		(130,191	)		(43,416,482	)
Net decrease		(687	)	$	(242,086	)		(129,325	)	$	(43,133,147	)
	Period from 07/01/19 (a) to 12/31/19
Class G
Shares sold		15,586,185		$	5,355,968,816
Shares issued in reinvestment of distributions		164,870			60,324,797
Shares redeemed		(605,458	)		(222,735,249	)
Net increase		15,145,597		$	5,193,558,364
	Year Ended December 31, 2019						Year Ended December 31, 2018
Class K
Shares sold		10,010,359		$	3,453,144,534			15,764,642		$	5,135,616,474
Shares issued in reinvestment of distributions		382,884			134,229,627			625,798			200,507,786
Shares redeemed		(19,774,859	)		(6,743,443,728	)		(5,660,927	)		(1,857,697,084	)
Net increase (decrease)		(9,381,616	)	$	(3,156,069,567	)		10,729,513		$	3,478,427,176
							Period from 08/06/18 (a) to 12/31/18
Investor P
Shares sold		213,019		$	73,377,508			23,517		$	7,319,688
Shares issued in reinvestment of distributions		62,206			22,021,815			29,882			9,201,465
Shares issued in reorganization		—			—			3,595,122			1,172,916,876
Shares redeemed		(512,490	)		(176,010,576	)		(66,741	)		(20,245,089	)
Net increase (decrease)		(237,265	)		(80,611,253	)		3,581,780			1,169,192,940
		3,054,273		$	1,109,955,590			15,386,365		$	5,000,372,689

^(a)  Commencement of operations.

As of December 31, 2019, shares owned by BlackRock Financial Management, Inc., an affiliate of the Fund, were as follows:

Class G	143
Investor P	589

7. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Fund through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 21

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of

BlackRock Funds III and Shareholders of iShares S&P 500 Index Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of iShares S&P 500 Index Fund (one of the series constituting BlackRock Funds III, referred to hereafter as the “Fund”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statement of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the periods indicated therein (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the periods indicated therein in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolio. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 14, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

Important Tax Information  (unaudited)

During the fiscal year ended December 31, 2019, the following information is provided with respect to the ordinary income distributions paid by the Fund:

	January 2019 — December 2019
Qualified Dividend Income for Individuals(a)		100.00	%
Dividends Qualifying for the Dividends Received Deduction for Corporations(a)		97.71	%
Federal Obligation Interest(b)		0.59	%
Interest-Related Dividends for Non-U.S. Residents(c)		1.13	%

^(a)  The Fund hereby designates the percentage indicated above or the maximum amount allowable by law.

^(b)  The law varies in each state as to whether and what percentage of dividend income attributable to federal obligations is exempt from state income tax. We recommend that you consult your tax advisor to determine if any portion of the dividends you received is exempt from state income taxes.

^(c)  Represents the portion of the taxable ordinary income dividends eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations.

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Master Portfolio Information  as of December 31, 2019 S&P 500 Index Master Portfolio

TEN LARGEST HOLDINGS

Security	Percent of Net Assets
Apple, Inc.		5	%
Microsoft Corp.		4
Amazon.com, Inc.		3
Facebook, Inc., Class A		2
Berkshire Hathaway, Inc.		2
JPMorgan Chase & Co.		2
Alphabet, Inc., Class A		1
Alphabet, Inc., Class C		1
Johnson & Johnson		1
Visa, Inc.		1

SECTOR ALLOCATION

Sector	Percent of Net Assets
Information Technology		23	%
Health Care		14
Financials		13
Consumer Discretionary		10
Communication Services		10
Industrials		9
Consumer Staples		7
Energy		4
Utilities		3
Real Estate		3
Materials		3
Short-Term Securities		2
Investment Companies		—	(a)
Liabilities in Excess of Other Assets		(1	)

^(a)  Represents less than 1%.

For Master Portfolio compliance purposes, the Master Portfolio’s sector classifications refer to one or more of the sectorsub-classifications used by one or more widely recognized market indexes or ratings group indexes, and/or as defined by the investment adviser. These definitions may not apply for purposes of this report, which may combine such sector sub-classifications for reporting ease.

MASTER PORTFOLIO INFORMATION 23

Schedule of Investments December 31, 2019 S&P 500 Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Common Stocks — 98.6%
Aerospace & Defense — 2.4%
Arconic, Inc.		327,315	$	10,071,483
Boeing Co.		457,205		148,939,101
General Dynamics Corp.		200,393		35,339,305
Huntington Ingalls Industries, Inc.		34,816		8,734,638
L3Harris Technologies, Inc.		189,043		37,405,938
Lockheed Martin Corp.		212,266		82,652,135
Northrop Grumman Corp.		134,032		46,102,987
Raytheon Co.		238,140		52,328,884
Textron, Inc.		195,208		8,706,277
TransDigm Group, Inc.		42,586		23,848,160
United Technologies Corp.		693,790		103,901,990
				558,030,898
Air Freight & Logistics — 0.5%
C.H. Robinson Worldwide, Inc.		115,658		9,044,455
Expeditors International of Washington, Inc.		145,632		11,362,209
FedEx Corp.		205,267		31,038,423
United Parcel Service, Inc., Class B		599,247		70,147,854
				121,592,941
Airlines — 0.4%
Alaska Air Group, Inc.		104,278		7,064,834
American Airlines Group, Inc.		333,289		9,558,729
Delta Air Lines, Inc.		492,223		28,785,201
Southwest Airlines Co.		405,266		21,876,259
United Airlines Holdings, Inc.(a)		185,099		16,305,371
				83,590,394
Auto Components — 0.1%
Aptiv PLC		218,308		20,732,711
BorgWarner, Inc.		176,581		7,660,084
				28,392,795
Automobiles — 0.3%
Ford Motor Co.		3,329,973		30,968,749
General Motors Co.		1,075,199		39,352,284
Harley-Davidson, Inc.		133,402		4,961,220
				75,282,253
Banks — 5.6%
Bank of America Corp.		6,922,909		243,824,855
Citigroup, Inc.		1,866,948		149,150,476
Citizens Financial Group, Inc.		374,540		15,210,070
Comerica, Inc.		123,273		8,844,838
Fifth Third Bancorp		611,953		18,811,435
First Republic Bank		144,111		16,925,837
Huntington Bancshares, Inc.		884,212		13,333,917
JPMorgan Chase & Co.		2,682,150		373,891,710
KeyCorp		840,464		17,010,991
M&T Bank Corp.		113,343		19,239,974
People’s United Financial, Inc.		379,790		6,418,451
PNC Financial Services Group, Inc.		374,698		59,813,042
Regions Financial Corp.		833,745		14,307,064
SVB Financial Group(a)(b)		44,213		11,099,232
Truist Financial Corp.		1,146,804		64,588,001
U.S. Bancorp		1,215,411		72,061,718
Wells Fargo & Co.		3,291,211		177,067,152
Zions Bancorp. NA		145,771		7,568,430
				1,289,167,193
Beverages — 1.8%
Brown-Forman Corp., Class B(b)		156,572		10,584,267
Coca-Cola Co.		3,297,475		182,515,241
Constellation Brands, Inc., Class A		143,235		27,178,841
Molson Coors Brewing Co., Class B		161,725		8,716,978

Security	Shares		Value
Beverages (continued)
Monster Beverage Corp.(a)		324,637	$	20,630,681
PepsiCo, Inc.		1,192,444		162,971,322
				412,597,330
Biotechnology — 2.0%
AbbVie, Inc.		1,264,606		111,968,215
Alexion Pharmaceuticals, Inc.(a)		189,913		20,539,091
Amgen, Inc.		508,114		122,491,042
Biogen, Inc.(a)		154,517		45,849,830
Gilead Sciences, Inc.		1,081,883		70,300,757
Incyte Corp.(a)(b)		152,882		13,349,656
Regeneron Pharmaceuticals, Inc.(a)(b)		68,310		25,649,039
Vertex Pharmaceuticals, Inc.(a)		219,901		48,147,324
				458,294,954
Building Products — 0.3%
Allegion PLC		79,458		9,895,700
AO Smith Corp.		116,550		5,552,442
Fortune Brands Home & Security, Inc.		118,250		7,726,455
Johnson Controls International PLC		659,676		26,855,410
Masco Corp.		243,172		11,669,824
				61,699,831
Capital Markets — 2.6%
Ameriprise Financial, Inc.		108,343		18,047,777
Bank of New York Mellon Corp.		718,627		36,168,497
BlackRock, Inc.(e)		100,848		50,696,290
Cboe Global Markets, Inc.		95,502		11,460,240
Charles Schwab Corp.		979,258		46,573,510
CME Group, Inc.		306,451		61,510,845
E*Trade Financial Corp.		193,191		8,765,076
Franklin Resources, Inc.		241,326		6,269,649
Goldman Sachs Group, Inc.		272,516		62,659,604
Intercontinental Exchange, Inc.		476,188		44,071,199
Invesco Ltd.		327,515		5,888,720
MarketAxess Holdings, Inc.(b)		32,431		12,294,916
Moody’s Corp.		138,848		32,963,904
Morgan Stanley		1,052,280		53,792,554
MSCI, Inc.		72,437		18,701,785
Nasdaq, Inc.		97,151		10,404,872
Northern Trust Corp.		181,190		19,249,626
Raymond James Financial, Inc.		105,579		9,445,097
S&P Global, Inc.		208,997		57,066,631
State Street Corp.		312,123		24,688,929
T. Rowe Price Group, Inc.		199,828		24,347,043
				615,066,764
Chemicals — 1.9%
Air Products & Chemicals, Inc.		188,503		44,296,320
Albemarle Corp.		90,674		6,622,829
Celanese Corp.		103,779		12,777,270
CF Industries Holdings, Inc.		183,499		8,760,242
Corteva, Inc.(a)		639,991		18,918,134
Dow, Inc.(a)		634,087		34,703,582
DuPont de Nemours, Inc.		633,497		40,670,507
Eastman Chemical Co.		114,764		9,096,195
Ecolab, Inc.		214,447		41,386,127
FMC Corp.		109,532		10,933,484
International Flavors & Fragrances, Inc.		91,710		11,832,424
Linde PLC		459,363		97,798,383
LyondellBasell Industries NV, Class A		219,538		20,741,950
Mosaic Co.(b)		301,320		6,520,565
PPG Industries, Inc.		202,210		26,993,013
Sherwin-Williams Co.		70,254		40,996,019
				433,047,044

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 S&P 500 Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Commercial Services & Supplies — 0.4%
Cintas Corp.(b)		71,691	$	19,290,614
Copart, Inc.(a)(b)		174,928		15,907,952
Republic Services, Inc.		180,124		16,144,514
Rollins, Inc.		120,824		4,006,524
Waste Management, Inc.		333,765		38,035,860
				93,385,464
Communications Equipment — 1.0%
Arista Networks, Inc.(a)(b)		45,858		9,327,517
Cisco Systems, Inc.		3,627,750		173,986,890
F5 Networks, Inc.(a)		51,988		7,260,124
Juniper Networks, Inc.		290,641		7,158,488
Motorola Solutions, Inc.		146,517		23,609,750
				221,342,769
Construction & Engineering — 0.1%
Jacobs Engineering Group, Inc.		116,069		10,426,478
Quanta Services, Inc.		121,753		4,956,565
				15,383,043
Construction Materials — 0.1%
Martin Marietta Materials, Inc.(b)		53,447		14,945,919
Vulcan Materials Co.		113,183		16,297,220
				31,243,139
Consumer Finance — 0.7%
American Express Co.		573,787		71,430,744
Capital One Financial Corp.		398,259		40,984,834
Discover Financial Services		268,061		22,736,934
Synchrony Financial		511,323		18,412,741
				153,565,253
Containers & Packaging — 0.3%
Amcor PLC(a)		1,385,456		15,018,343
Avery Dennison Corp.		70,531		9,226,865
Ball Corp.(b)		278,130		17,986,667
International Paper Co.		335,316		15,441,302
Packaging Corp. of America		81,400		9,115,986
Sealed Air Corp.		133,968		5,335,946
Westrock Co.		221,545		9,506,496
				81,631,605
Distributors — 0.1%
Genuine Parts Co.		124,507		13,226,379
LKQ Corp.(a)		263,623		9,411,341
				22,637,720
Diversified Consumer Services — 0.0%
H&R Block, Inc.		171,262		4,021,232
Diversified Financial Services — 1.6%
Berkshire Hathaway, Inc., Class B(a)(b)		1,672,696		378,865,644
Diversified Telecommunication Services — 2.0%
AT&T, Inc.		6,246,835		244,126,312
CenturyLink, Inc.		839,468		11,089,372
Verizon Communications, Inc.		3,536,695		217,153,073
				472,368,757
Electric Utilities — 2.0%
Alliant Energy Corp.		205,536		11,246,930
American Electric Power Co., Inc.		422,401		39,921,119
Duke Energy Corp.		623,429		56,862,959
Edison International		306,656		23,124,929
Entergy Corp.		170,261		20,397,268
Evergy, Inc.		194,890		12,685,390
Eversource Energy		276,863		23,552,735
Exelon Corp.		831,294		37,898,693
FirstEnergy Corp.		462,045		22,455,387

Security	Shares		Value
Electric Utilities (continued)
NextEra Energy, Inc.		417,974	$	101,216,584
Pinnacle West Capital Corp.		96,814		8,706,483
PPL Corp.		618,298		22,184,532
Southern Co.		896,820		57,127,434
Xcel Energy, Inc.		448,428		28,470,694
				465,851,137
Electrical Equipment — 0.5%
AMETEK, Inc.(b)		195,480		19,497,175
Eaton Corp. PLC		354,242		33,553,802
Emerson Electric Co.		520,915		39,724,978
Rockwell Automation, Inc.		99,131		20,090,880
				112,866,835
Electronic Equipment, Instruments & Components — 0.6%
Amphenol Corp., Class A		253,544		27,441,067
CDW Corp.		122,868		17,550,465
Corning, Inc.		654,158		19,042,539
FLIR Systems, Inc.		113,633		5,916,870
IPG Photonics Corp.(a)(b)		29,995		4,346,875
Keysight Technologies, Inc.(a)(b)		160,406		16,462,468
TE Connectivity Ltd.		286,025		27,412,636
Zebra Technologies Corp., Class A(a)		46,110		11,778,339
				129,951,259
Energy Equipment & Services — 0.4%
Baker Hughes Co.		555,732		14,243,411
Halliburton Co.		750,650		18,368,405
Helmerich & Payne, Inc.		90,592		4,115,595
National Oilwell Varco, Inc.		326,024		8,166,901
Schlumberger Ltd.		1,183,853		47,590,891
TechnipFMC PLC		362,703		7,776,352
				100,261,555
Entertainment — 0.9%
Activision Blizzard, Inc.		656,974		39,037,395
Electronic Arts, Inc.(a)		249,684		26,843,527
Live Nation Entertainment, Inc.(a)		120,504		8,612,421
Netflix, Inc.(a)		374,768		121,263,682
Take-Two Interactive Software, Inc.(a)		96,784		11,849,265
				207,606,290
Equity Real Estate Investment Trusts (REITs) — 2.8%
Alexandria Real Estate Equities, Inc.		98,471		15,910,944
American Tower Corp.		378,778		87,050,760
Apartment Investment & Management Co., Class A		128,731		6,648,956
AvalonBay Communities, Inc.		119,431		25,044,681
Boston Properties, Inc.		121,980		16,816,163
Crown Castle International Corp.		355,542		50,540,295
Digital Realty Trust, Inc.		178,486		21,371,914
Duke Realty Corp.		314,327		10,897,717
Equinix, Inc.		72,926		42,566,906
Equity Residential		299,340		24,222,593
Essex Property Trust, Inc.		56,510		17,001,598
Extra Space Storage, Inc.		110,751		11,697,521
Federal Realty Investment Trust		61,405		7,904,666
Healthpeak Properties, Inc.		423,257		14,589,669
Host Hotels & Resorts, Inc.		607,358		11,266,491
Iron Mountain, Inc.		245,549		7,825,647
Kimco Realty Corp.		361,070		7,477,760
Mid-America Apartment Communities, Inc.		97,543		12,862,020
Prologis, Inc.		540,236		48,156,637
Public Storage		128,464		27,357,693
Realty Income Corp.		278,708		20,521,270
Regency Centers Corp.		143,993		9,084,518
SBA Communications Corp.		96,290		23,204,927
Simon Property Group, Inc.		262,411		39,088,742

SCHEDULE OF INVESTMENTS 25

Schedule of Investments  (continued) December 31, 2019 S&P 500 Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Equity Real Estate Investment Trusts (REITs) (continued)
SL Green Realty Corp.		70,082	$	6,439,134
UDR, Inc.		250,603		11,703,160
Ventas, Inc.		318,743		18,404,221
Vornado Realty Trust		135,460		9,008,090
Welltower, Inc.		346,982		28,376,188
Weyerhaeuser Co.		637,205		19,243,591
				652,284,472
Food & Staples Retailing — 1.5%
Costco Wholesale Corp.		377,789		111,039,743
Kroger Co.		685,826		19,882,096
Sysco Corp.		436,318		37,322,642
Walgreens Boots Alliance, Inc.		641,132		37,801,142
Walmart, Inc.		1,213,098		144,164,566
				350,210,189
Food Products — 1.1%
Archer-Daniels-Midland Co.		476,047		22,064,779
Campbell Soup Co.		143,388		7,086,235
Conagra Brands, Inc.		416,160		14,249,318
General Mills, Inc.		516,845		27,682,218
Hershey Co.		126,825		18,640,739
Hormel Foods Corp.		237,784		10,726,436
J.M. Smucker Co.		97,733		10,176,937
Kellogg Co.		212,930		14,726,239
Kraft Heinz Co.		532,578		17,111,731
Lamb Weston Holdings, Inc.		124,905		10,745,577
McCormick & Co., Inc.		105,670		17,935,369
Mondelez International, Inc., Class A		1,231,258		67,817,691
Tyson Foods, Inc., Class A		252,425		22,980,772
				261,944,041
Gas Utilities — 0.0%
Atmos Energy Corp.		102,056		11,415,984
Health Care Equipment & Supplies — 3.5%
Abbott Laboratories		1,511,382		131,278,641
ABIOMED, Inc.(a)		38,162		6,510,056
Align Technology, Inc.(a)		60,889		16,990,467
Baxter International, Inc.		436,599		36,508,408
Becton Dickinson & Co.		231,283		62,902,037
Boston Scientific Corp.(a)(b)		1,191,922		53,898,713
Cooper Cos., Inc.		42,393		13,620,447
Danaher Corp.		534,857		82,089,852
DENTSPLY SIRONA, Inc.		191,806		10,854,302
Edwards Lifesciences Corp.(a)		178,358		41,609,138
Hologic, Inc.(a)		229,303		11,971,910
IDEXX Laboratories, Inc.(a)		73,357		19,155,713
Intuitive Surgical, Inc.(a)		98,833		58,425,128
Medtronic PLC		1,146,218		130,038,432
ResMed, Inc.		122,958		19,054,801
STERIS PLC		72,502		11,050,755
Stryker Corp.		275,343		57,805,509
Teleflex, Inc.(b)		39,590		14,903,260
Varian Medical Systems, Inc.(a)		77,926		11,066,271
Zimmer Biomet Holdings, Inc.		175,890		26,327,215
				816,061,055
Health Care Providers & Services — 2.8%
AmerisourceBergen Corp.		127,499		10,839,965
Anthem, Inc.		216,834		65,490,373
Cardinal Health, Inc.		249,757		12,632,709
Centene Corp.(a)		353,856		22,246,927
Cigna Corp.(a)		319,333		65,300,405
CVS Health Corp.		1,112,513		82,648,591
DaVita, Inc.(a)(b)		76,688		5,753,901
HCA Healthcare, Inc.		226,236		33,439,943

Security	Shares		Value
Health Care Providers & Services (continued)
Henry Schein, Inc.(a)(b)		124,314	$	8,294,230
Humana, Inc.		113,168		41,478,335
Laboratory Corp. of America Holdings(a)		83,386		14,106,410
McKesson Corp.		154,900		21,425,768
Quest Diagnostics, Inc.		115,185		12,300,606
UnitedHealth Group, Inc.		810,177		238,175,834
Universal Health Services, Inc., Class B		69,185		9,925,280
WellCare Health Plans, Inc.(a)		43,014		14,203,653
				658,262,930
Health Care Technology — 0.1%
Cerner Corp.		266,769		19,578,177
Hotels, Restaurants & Leisure — 1.8%
Carnival Corp.		342,538		17,411,207
Chipotle Mexican Grill, Inc.(a)		21,867		18,305,084
Darden Restaurants, Inc.		104,842		11,428,826
Hilton Worldwide Holdings, Inc.		241,409		26,774,672
Las Vegas Sands Corp.		288,985		19,951,524
Marriott International, Inc., Class A		232,050		35,139,332
McDonald’s Corp.		644,004		127,261,630
MGM Resorts International		436,817		14,532,902
Norwegian Cruise Line Holdings Ltd.(a)		182,061		10,634,183
Royal Caribbean Cruises Ltd.		146,997		19,625,569
Starbucks Corp.		1,009,926		88,792,694
Wynn Resorts Ltd.		81,809		11,360,816
Yum! Brands, Inc.		258,649		26,053,714
				427,272,153
Household Durables — 0.4%
D.R. Horton, Inc.		286,755		15,126,326
Garmin Ltd.		123,550		12,053,538
Leggett & Platt, Inc.		110,137		5,598,264
Lennar Corp., Class A		238,254		13,292,191
Mohawk Industries, Inc.(a)(b)		50,377		6,870,415
Newell Brands, Inc.		319,095		6,133,006
NVR, Inc.(a)		2,970		11,310,978
PulteGroup, Inc.		215,939		8,378,433
Whirlpool Corp.		53,219		7,851,399
				86,614,550
Household Products — 1.7%
Church & Dwight Co., Inc.		210,296		14,792,221
Clorox Co.		107,323		16,478,373
Colgate-Palmolive Co.		732,897		50,452,629
Kimberly-Clark Corp.		293,149		40,322,645
Procter & Gamble Co.		2,132,571		266,358,118
				388,403,986
Independent Power and Renewable Electricity Producers — 0.1%
AES Corp.		568,095		11,305,090
NRG Energy, Inc.		211,937		8,424,496
				19,729,586
Industrial Conglomerates — 1.3%
3M Co.		491,752		86,754,888
General Electric Co.		7,468,451		83,347,913
Honeywell International, Inc.		611,029		108,152,133
Roper Technologies, Inc.		88,985		31,521,157
				309,776,091
Insurance — 2.3%
Aflac, Inc.		627,692		33,204,907
Allstate Corp.		275,775		31,010,899
American International Group, Inc.		743,935		38,186,184
Aon PLC		200,221		41,704,032
Arthur J Gallagher & Co.		159,504		15,189,566
Assurant, Inc.		52,112		6,830,841

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 S&P 500 Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Insurance (continued)
Chubb Ltd.		387,553	$	60,326,500
Cincinnati Financial Corp.		129,928		13,661,929
Everest Re Group Ltd.		34,875		9,654,795
Globe Life, Inc.		85,194		8,966,668
Hartford Financial Services Group, Inc.		308,212		18,730,043
Lincoln National Corp.		169,602		10,008,214
Loews Corp.(b)		219,232		11,507,488
Marsh & McLennan Cos., Inc.		431,564		48,080,545
MetLife, Inc.		666,820		33,987,815
Principal Financial Group, Inc.		221,337		12,173,535
Progressive Corp.		499,943		36,190,874
Prudential Financial, Inc.		343,768		32,224,812
Travelers Cos., Inc.		220,724		30,228,152
Unum Group		173,973		5,073,053
W.R. Berkley Corp.		124,448		8,599,357
Willis Towers Watson PLC		109,948		22,202,899
				527,743,108
Interactive Media & Services — 4.9%
Alphabet, Inc., Class A(a)		256,225		343,185,203
Alphabet, Inc., Class C(a)		255,594		341,734,290
Facebook, Inc., Class A(a)		2,057,879		422,379,664
Twitter, Inc.(a)		663,898		21,277,931
				1,128,577,088
Internet & Direct Marketing Retail — 3.3%
Amazon.com, Inc.(a)		356,142		658,093,433
Booking Holdings, Inc.(a)(b)		35,793		73,509,158
eBay, Inc.		653,941		23,613,810
Expedia Group, Inc.		119,502		12,922,946
				768,139,347
IT Services — 5.3%
Accenture PLC, Class A		543,071		114,354,460
Akamai Technologies, Inc.(a)(b)		138,211		11,938,666
Alliance Data Systems Corp.		34,374		3,856,763
Automatic Data Processing, Inc.		370,020		63,088,410
Broadridge Financial Solutions, Inc.		98,039		12,111,738
Cognizant Technology Solutions Corp., Class A		468,248		29,040,741
DXC Technology Co.		220,706		8,296,339
Fidelity National Information Services, Inc.		525,572		73,101,809
Fiserv, Inc.(a)		488,383		56,471,726
FleetCor Technologies, Inc.(a)		74,210		21,351,701
Gartner, Inc.(a)(b)		76,998		11,865,392
Global Payments, Inc.		257,012		46,920,111
International Business Machines Corp.		757,348		101,514,926
Jack Henry & Associates, Inc.		65,792		9,583,921
Leidos Holdings, Inc.		113,726		11,132,638
Mastercard, Inc., Class A		759,138		226,671,015
Paychex, Inc.		272,424		23,172,385
PayPal Holdings, Inc.(a)		1,004,105		108,614,038
VeriSign, Inc.(a)		88,454		17,043,317
Visa, Inc., Class A		1,463,870		275,061,173
Western Union Co.		355,433		9,518,496
				1,234,709,765
Leisure Products — 0.0%
Hasbro, Inc.		108,821		11,492,586
Life Sciences Tools & Services — 1.0%
Agilent Technologies, Inc.		264,640		22,576,438
Illumina, Inc.(a)		125,706		41,701,709
IQVIA Holdings, Inc.(a)		154,315		23,843,211
Mettler-Toledo International, Inc.(a)		20,929		16,602,557
PerkinElmer, Inc.(b)		95,779		9,300,141
Thermo Fisher Scientific, Inc.(b)		342,905		111,399,547

Security	Shares		Value
Life Sciences Tools & Services (continued)
Waters Corp.(a)(b)		55,926	$	13,067,110
				238,490,713
Machinery — 1.6%
Caterpillar, Inc.		472,837		69,828,568
Cummins, Inc.		132,183		23,655,470
Deere & Co.		269,262		46,652,334
Dover Corp.		124,224		14,318,058
Flowserve Corp.		112,148		5,581,606
Fortive Corp.		252,702		19,303,906
IDEX Corp.		65,042		11,187,224
Illinois Tool Works, Inc.		250,112		44,927,618
Ingersoll-Rand PLC		204,890		27,233,979
PACCAR, Inc.		295,772		23,395,565
Parker-Hannifin Corp.		109,856		22,610,562
Pentair PLC		140,780		6,457,579
Snap-on, Inc.		46,909		7,946,385
Stanley Black & Decker, Inc.		129,992		21,544,874
Westinghouse Air Brake Technologies Corp.		154,199		11,996,682
Xylem, Inc.		153,994		12,133,187
				368,773,597
Media — 2.4%
Charter Communications, Inc., Class A(a)(b)		134,078		65,038,556
Comcast Corp., Class A		3,882,193		174,582,219
Discovery, Inc., Class A(a)(b)		134,754		4,411,846
Discovery, Inc., Class C(a)(b)		286,831		8,745,477
DISH Network Corp., Class A(a)		218,051		7,734,269
Fox Corp., Class A		303,158		11,238,067
Fox Corp., Class B(a)		133,124		4,845,714
Interpublic Group of Cos., Inc.		327,050		7,554,855
News Corp., Class A		332,273		4,698,340
News Corp., Class B		95,128		1,380,307
Omnicom Group, Inc.		186,192		15,085,276
ViacomCBS, Inc., Class B Class B		462,120		19,395,176
Walt Disney Co.(b)		1,541,312		222,919,955
				547,630,057
Metals & Mining — 0.3%
Freeport-McMoRan, Inc.		1,240,742		16,278,535
Newmont Goldcorp Corp.		701,081		30,461,969
Nucor Corp.		259,293		14,593,010
				61,333,514
Multi-Utilities — 1.0%
Ameren Corp.		210,391		16,158,029
CenterPoint Energy, Inc.		429,490		11,712,192
CMS Energy Corp.		242,726		15,252,902
Consolidated Edison, Inc.		284,276		25,718,450
Dominion Energy, Inc.		703,864		58,294,016
DTE Energy Co.		164,278		21,334,784
NiSource, Inc.		321,488		8,950,226
Public Service Enterprise Group, Inc.		432,469		25,537,294
Sempra Energy		241,062		36,516,072
WEC Energy Group, Inc.		269,744		24,878,489
				244,352,454
Multiline Retail — 0.5%
Dollar General Corp.		217,720		33,959,966
Dollar Tree, Inc.(a)		202,380		19,033,839
Kohl’s Corp.		132,816		6,766,975
Macy’s, Inc.		267,347		4,544,899
Nordstrom, Inc.		88,174		3,608,962
Target Corp.		433,334		55,557,752
				123,472,393

SCHEDULE OF INVESTMENTS 27

Schedule of Investments  (continued) December 31, 2019 S&P 500 Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Oil, Gas & Consumable Fuels — 3.9%
Apache Corp.		317,469	$	8,124,032
Cabot Oil & Gas Corp.		349,750		6,089,148
Chevron Corp.		1,616,970		194,861,055
Cimarex Energy Co.		87,062		4,569,884
Concho Resources, Inc.		171,909		15,054,071
ConocoPhillips		938,324		61,019,210
Devon Energy Corp.		330,941		8,594,538
Diamondback Energy, Inc.		136,845		12,707,427
EOG Resources, Inc.		497,493		41,670,014
Exxon Mobil Corp.		3,618,209		252,478,624
Hess Corp.		221,483		14,797,279
HollyFrontier Corp.		129,331		6,558,375
Kinder Morgan, Inc.		1,665,711		35,263,102
Marathon Oil Corp.		684,055		9,289,467
Marathon Petroleum Corp.		555,265		33,454,716
Noble Energy, Inc.		412,314		10,241,880
Occidental Petroleum Corp.		763,916		31,480,978
ONEOK, Inc.		353,248		26,730,276
Phillips 66		379,991		42,334,797
Pioneer Natural Resources Co.		141,652		21,441,863
Valero Energy Corp.		351,168		32,886,883
Williams Cos., Inc.		1,036,478		24,585,258
				894,232,877
Personal Products — 0.2%
Coty, Inc., Class A		246,388		2,771,865
Estee Lauder Cos., Inc., Class A(b)		190,313		39,307,247
				42,079,112
Pharmaceuticals — 4.6%
Allergan PLC		280,724		53,666,007
Bristol-Myers Squibb Co.		2,004,618		128,676,429
Eli Lilly & Co.		722,525		94,961,461
Johnson & Johnson		2,250,632		328,299,690
Merck & Co., Inc.		2,177,186		198,015,066
Mylan NV(a)		441,369		8,871,517
Perrigo Co. PLC		116,394		6,012,914
Pfizer, Inc.		4,732,477		185,418,449
Zoetis, Inc.		407,305		53,906,817
				1,057,828,350
Professional Services — 0.3%
Equifax, Inc.		103,544		14,508,585
IHS Markit Ltd.(a)(b)		342,903		25,837,741
Nielsen Holdings PLC		301,186		6,114,076
Robert Half International, Inc.		98,758		6,236,568
Verisk Analytics, Inc.(b)		140,133		20,927,462
				73,624,432
Real Estate Management & Development — 0.1%
CBRE Group, Inc., Class A(a)		286,262		17,544,998
Road & Rail — 1.0%
CSX Corp.		664,992		48,118,821
JB Hunt Transport Services, Inc.		73,282		8,557,872
Kansas City Southern		84,265		12,906,027
Norfolk Southern Corp.		222,977		43,286,525
Old Dominion Freight Line, Inc.		54,811		10,402,032
Union Pacific Corp.		593,642		107,324,537
				230,595,814
Semiconductors & Semiconductor Equipment — 4.2%
Advanced Micro Devices, Inc.(a)		952,313		43,673,074
Analog Devices, Inc.		314,952		37,428,896
Applied Materials, Inc.		789,944		48,218,182
Broadcom, Inc.		339,211		107,197,460
Intel Corp.		3,719,881		222,634,878
KLA Corp.		134,937		24,041,725

Security	Shares		Value
Semiconductors & Semiconductor Equipment (continued)
Lam Research Corp.		124,064	$	36,276,314
Maxim Integrated Products, Inc.		231,410		14,234,029
Microchip Technology, Inc.		204,361		21,400,684
Micron Technology, Inc.(a)		946,689		50,912,934
NVIDIA Corp.		523,349		123,144,020
Qorvo, Inc.(a)		99,482		11,562,793
QUALCOMM, Inc.		976,443		86,151,566
Skyworks Solutions, Inc.		145,792		17,623,337
Texas Instruments, Inc.		799,368		102,550,921
Xilinx, Inc.		215,041		21,024,558
				968,075,371
Software — 7.0%
Adobe, Inc.(a)		413,958		136,527,488
ANSYS, Inc.(a)(b)		73,184		18,838,294
Autodesk, Inc.(a)		188,160		34,519,834
Cadence Design Systems, Inc.(a)		239,948		16,642,793
Citrix Systems, Inc.		104,676		11,608,568
Fortinet, Inc.(a)		121,395		12,960,130
Intuit, Inc.		222,600		58,305,618
Microsoft Corp.		6,523,736		1,028,793,167
NortonLifeLock, Inc.		490,329		12,513,196
Oracle Corp.		1,852,639		98,152,814
salesforce.com, Inc.(a)		758,514		123,364,717
ServiceNow, Inc.(a)(b)		161,280		45,532,570
Synopsys, Inc.(a)		128,555		17,894,856
				1,615,654,045
Specialty Retail — 2.2%
Advance Auto Parts, Inc.		59,306		9,498,449
AutoZone, Inc.(a)		20,549		24,480,229
Best Buy Co., Inc.		194,308		17,060,242
CarMax, Inc.(a)		141,009		12,362,259
Gap, Inc.		180,058		3,183,425
Home Depot, Inc.		932,819		203,709,013
L Brands, Inc.		200,125		3,626,265
Lowe’s Cos., Inc.		655,447		78,496,333
O’Reilly Automotive, Inc.(a)(b)		64,699		28,354,984
Ross Stores, Inc.		309,332		36,012,432
Tiffany & Co.		92,777		12,399,646
TJX Cos., Inc.		1,037,007		63,319,647
Tractor Supply Co.		101,563		9,490,047
Ulta Salon Cosmetics & Fragrance, Inc.(a)(b)		49,300		12,479,802
				514,472,773
Technology Hardware, Storage & Peripherals — 4.9%
Apple, Inc.		3,571,658		1,048,817,372
Hewlett Packard Enterprise Co.		1,097,787		17,410,902
HP, Inc.		1,267,251		26,042,008
NetApp, Inc.		195,166		12,149,083
Seagate Technology PLC		198,698		11,822,531
Western Digital Corp.		254,324		16,141,944
Xerox Holdings Corp.(a)		160,203		5,906,685
				1,138,290,525
Textiles, Apparel & Luxury Goods — 0.7%
Capri Holdings Ltd.(a)(b)		130,344		4,972,623
Hanesbrands, Inc.		313,302		4,652,535
NIKE, Inc., Class B		1,065,535		107,949,351
PVH Corp.(b)		63,061		6,630,864
Ralph Lauren Corp.		42,619		4,995,799
Tapestry, Inc.		237,843		6,414,626
Under Armour, Inc., Class A(a)(b)		164,871		3,561,214
Under Armour, Inc., Class C(a)(b)		169,421		3,249,495
VF Corp.		280,049		27,909,683
				170,336,190

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 S&P 500 Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Tobacco — 0.8%
Altria Group, Inc.		1,597,520	$	79,732,223
Philip Morris International, Inc.		1,330,499		113,212,160
				192,944,383
Trading Companies & Distributors — 0.2%
Fastenal Co.		490,449		18,122,090
United Rentals, Inc.(a)(b)		64,479		10,753,163
W.W. Grainger, Inc.		37,030		12,535,396
				41,410,649
Water Utilities — 0.1%
American Water Works Co., Inc.		154,590		18,991,381
Wireless Telecommunication Services — 0.1%
T-Mobile U.S., Inc.(a)		270,707		21,228,843
Total Common Stocks — 98.6% (Cost — $13,108,218,270)				22,881,321,678
Investment Companies — 0.4%
iShares Core S&P 500 ETF(e)		292,674		94,603,944
Total Investment Companies — 0.4% (Cost — $88,157,092)				94,603,944
Total Long-Term Investments — 99.0% (Cost — $13,196,375,362)				22,975,925,622

Security	Shares		Value
Short-Term Securities — 1.5%
BlackRock Cash Funds: Institutional, SL Agency Shares, 1.84%(c)(d)(e)		139,348,114	$	139,403,854
BlackRock Cash Funds: Treasury, SL Agency Shares, 1.52%(d)(e)		215,380,072		215,380,072
Total Short-Term Securities — 1.5% (Cost — $354,767,438)				354,783,926
Total Investments — 100.5% (Cost — $13,551,142,800)				23,330,709,548
Liabilities in Excess of Other Assets — (0.5)%				(122,751,203	)
Net Assets — 100.0%			$	23,207,958,345

^(a)  Non-income producing security.

^(b)  Security, or a portion of the security, is on loan.

^(c)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(d)  Annualized7-day yield as of period end.

^(e)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, and/or related parties of the Master Portfolio were as follows:

Affiliated Persons and/or Related Parties	Shares Held at 12/31/18		Shares Purchased		Shares Sold			Shares Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)			Change in Unrealized Appreciation (Depreciation)
BlackRock, Inc.		98,827		4,735		(2,714	)		100,848	$	50,696,290	$	1,290,152		$	(361,626	)	$	11,125,951
BlackRock Cash Funds: Institutional, SL Agency Shares(b)		118,748,723		20,599,391		—			139,348,114		139,403,854		679,409	(c)		13,818			13,652
BlackRock Cash Funds: Treasury, SL Agency Shares(b)		479,801,017		—		(264,420,945	)		215,380,072		215,380,072		5,105,161			—			—
iShares Core S&P 500 ETF		—		292,674		—			292,674		94,603,944		647,089			—			6,446,852
										$	500,084,160	$	7,721,811		$	(347,808	)	$	17,586,455

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents net shares purchased (sold).

^(c)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
S&P 500E-Mini Index		1,479		03/20/20	$	238,940	$	2,345,486

SCHEDULE OF INVESTMENTS 29

Schedule of Investments  (continued) December 31, 2019 S&P 500 Index Master Portfolio

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statement of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	2,345,486	$	—	$	—	$	—	$	2,345,486

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts, if any, are reported in the Schedule of Investments. In the Statement of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in net unrealized appreciation (depreciation).

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statement of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	67,610,011	$	—	$	—	$	—	$	67,610,011
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	1,968,163	$	—	$	—	$	—	$	1,968,163

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	250,138,951

For more information about the Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Long-Term Investments(a)	$	22,975,925,622	$	—	$	—	$	22,975,925,622
Short-Term Securities		354,783,926		—		—		354,783,926
	$	23,330,709,548	$	—	$	—	$	23,330,709,548
Derivative Financial Instruments(b)
Assets:
Equity contracts	$	2,345,486	$	—	$	—	$	2,345,486

^(a)  See above Schedule of Investments for values in each industry.

^(b)  Derivative financial instruments are futures contracts. Futures contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	S&P 500 Index Master Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $137,214,328, cost — $13,076,378,623)	$	22,830,625,388
Investments at value — affiliated (cost — $474,764,177)		500,084,160
Cash		270,037
Cash pledged for futures contracts		9,411,800
Receivables:
Securities lending income — affiliated		186,784
Dividends — affiliated		459,684
Dividends — unaffiliated		22,795,533
Variation margin on futures contracts		569,390
Prepaid expenses		84,984
Total assets		23,364,487,760
LIABILITIES
Cash collateral on securities loaned at value		139,392,096
Payables:
Investment advisory fees		334,166
Trustees’ fees		82,740
Withdrawals to investors		16,720,413
Total liabilities		156,529,415
NET ASSETS	$	23,207,958,345
NET ASSETS CONSIST OF
Investors’ capital	$	13,426,046,111
Net unrealized appreciation (depreciation)		9,781,912,234
NET ASSETS	$	23,207,958,345

See notes to financial statements.

FINANCIAL STATEMENTS 31

Statement of Operations

Year Ended December 31, 2019

	S&P 500 Index Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	7,042,402
Dividends — unaffiliated		392,078,121
Securities lending income — affiliated — net		679,409
Foreign taxes withheld		(1,515,553	)
Total investment income		398,284,379
EXPENSES
Investment advisory		4,863,044
Trustees		310,692
Professional		75,099
Total expenses		5,248,835
Less fees waived and/or reimbursed by the Manager		(563,865	)
Total expenses after fees waived and/or reimbursed		4,684,970
Net investment income		393,599,409
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Futures contracts		67,610,011
Investments — affiliated		(347,808	)
Investments — unaffiliated		(13,455,802	)
		53,806,401
Net change in unrealized appreciation (depreciation) on:
Futures contracts		1,968,163
Investments — affiliated		17,586,455
Investments — unaffiliated		4,960,397,272
		4,979,951,890
Net realized and unrealized gain		5,033,758,291
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	5,427,357,700

See notes to financial statements.

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	S&P 500 Index Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	393,599,409		$	308,119,158
Net realized gain		53,806,401			68,976,788
Net change in unrealized appreciation (depreciation)		4,979,951,890			(1,302,602,820	)
Net increase (decrease) in net assets resulting from operations		5,427,357,700			(925,506,874	)
CAPITAL TRANSACTIONS
Proceeds from contributions		11,063,823,888			9,671,286,018
Value of withdrawals		(10,540,152,052	)		(5,263,924,715	)
Net increase in net assets derived from capital transactions		523,671,836			4,407,361,303
NET ASSETS
Total increase in net assets		5,951,029,536			3,481,854,429
Beginning of year		17,256,928,809			13,775,074,380
End of year	$	23,207,958,345		$	17,256,928,809

See notes to financial statements.

FINANCIAL STATEMENTS 33

Financial Highlights

(For a share outstanding throughout each period)

	S&P 500 Index Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		31.44	%		(4.38	)%		21.77	%		11.92	%		1.35	%
Ratios to Average Net Assets
Total expenses		0.03	%		0.04	%		0.04	%		0.04	%		0.05	%
Total expenses after fees waived and/or reimbursed		0.02	%		0.04	%		0.04	%		0.04	%		0.04	%
Net investment income		1.95	%		1.92	%		1.93	%		2.11	%		2.00	%
Supplemental Data
Net assets, end of year (000)	$	23,207,958		$	17,256,929		$	13,775,074		$	9,791,759		$	7,209,857
Portfolio turnover rate		3	%		12	%		11	%		4	%		2	%

See notes to financial statements.

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. S&P 500 Index Master Portfolio (the “Master Portfolio”) is a series of MIP. The Master Portfolio is classified as diversified.

The Master Portfolio, together with certain other registered investment companies advised by BlackRock Fund Advisors (the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

Prior Year Reorganization: The Board of BlackRock Funds III and the Board of State Farm Mutual Fund Trust and the shareholders of State Farm S&P 500 Index Fund (the “Target Fund”) approved the reorganization of the Target Fund into iShares S&P 500 Index Fund (the “Fund”), a series of BlackRock Funds III. As a result, the Fund acquired all of the assets and assumed certain stated liabilities of the Target Fund in exchange for an equal aggregate value of newly-issued shares of the Fund.

On November 19, 2018, all of the portfolio securities previously held by the Target Fund were subsequently contributed by the Fund to the Master Portfolio in exchange for an investment in the Master Portfolio.

For financial reporting purposes, assets received and shares issued by the Fund were recorded at fair value. However, the cost basis of the investments received from the Target Fund was carried forward by the Master Portfolio to align ongoing reporting of the Fund’s realized and unrealized gains and losses with amounts distributable to shareholders for tax purposes.

The Target Fund’s fair value and cost of investments prior to the reorganization were as follows:

Target Fund	Fair Value of Investments		Cost of Investments
State Farm S&P 500 Index Fund	$	1,473,476,973	$	726,300,157

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the Master Portfolio is informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain.

Segregation and Collateralization:In cases where the Master Portfolio enters into certain investments (e.g., futures contracts) that would be treated as “senior securities” for 1940 Act purposes, the Master Portfolio may segregate or designate on itsbooks and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the Master Portfolio may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, the Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. The Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Master Portfolio, which cannot be predicted with any certainty.

Other: Expenses directly related to the Master Portfolio are charged to the Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the New York Stock Exchange (“NYSE”) (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board of Trustees of MIP (the “Board”). The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of the Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

NOTESTO FINANCIAL STATEMENTS 35

Notes to Financial Statements  (continued)

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that the Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

4. SECURITIES AND OTHER INVESTMENTS

Securities Lending:The Master Portfolio may lend its securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the Master Portfolio collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by the Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the Master Portfolio and any additional required collateral is delivered to the Master Portfolio, or excess collateral returned by the Master Portfolio, on the next business day. During the term of the loan, the Master Portfolio is entitled to all distributions made on or in respect of the loaned securities, but does not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as common stocks in the Master Portfolio’s Schedule of Investments, and the value of any related collateral are shown separately in the Statement of Assets and Liabilities as a component of investments at value — unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedule of Investments.

Securities lending transactions are entered into by the Master Portfolio under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the Master Portfolio, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and the Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

As of period end, the following table is a summary of the Master Portfolio’s securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
Bank of America N.A.	$	5,539,671	$	(5,539,671	)	$	—
Barclays Bank PLC		3,843,919		(3,843,919	)		—
Barclays Capital, Inc.		50,783		(50,783	)		—
BMO Capital Markets		202,006		(202,006	)		—
Citigroup Global Markets, Inc.		53,451,965		(53,451,965	)		—
Credit Suisse Securities (USA) LLC		7,798,663		(7,798,663	)		—
Goldman Sachs & Co.		15,789,735		(15,789,735	)		—
HSBC Bank PLC		1,045,058		(1,045,058	)		—
JP Morgan Securities LLC		7,983,961		(7,983,961	)		—
Nomura Securities International, Inc.		174,471		(174,471	)		—
Scotia Capital (USA), Inc.		772,920		(772,920	)		—
SG Americas Securities LLC		16,396,672		(16,396,672	)		—
UBS AG		665,358		(665,358	)		—
UBS Securities LLC		22,906,558		(22,906,558	)		—
Wells Fargo Securities LLC		592,588		(592,588	)		—
	$	137,214,328	$	(137,214,328	)	$	—

^(a)  Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by the Master Portfolio is disclosed in the Master Portfolio’s Statement of Assets and Liabilities.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the Master Portfolio benefits from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”). BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. The Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the Master Portfolio.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The Master Portfolio engages in various portfolio investment strategies using derivative contracts both to increase the returns of the Master Portfolio and/or to manage its exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedule of Investments. These contracts may be transacted on an exchange orover-the-counter (“OTC”).

Futures Contracts:Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

Futures contracts are agreements between the Master Portfolio and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the Master Portfolio is required to deposit initial margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statement of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedule of Investments and cash deposited, if any, are shown as cash pledged for futures contracts in the Statement of Assets and Liabilities. Pursuant to the contract, the Master Portfolio agrees to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statement of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statement of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the Master Portfolio, entered into an Investment Advisory Agreement with the Manager, the Master Portfolio’s investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of the Master Portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Master Portfolio.

For such services, the Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.01% of the average daily value of the Master Portfolio’s net assets. Prior to July 1, 2019, the Master Portfolio paid the Manager a monthly fee at an annual rate equal to 0.04% of the average daily value of the Master Portfolio’s net assets.

Administration:MIP, on behalf of the Master Portfolio, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the Master Portfolio’s ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Master Portfolio.

NOTESTO FINANCIAL STATEMENTS 37

Notes to Financial Statements  (continued)

BAL is not entitled to compensation for providing administrative services to the Master Portfolio, for so long as BAL (or an affiliate) is entitled to compensation for providing administrative services to corresponding feeder funds that invest substantially all of their assets in the Master Portfolio, or BAL (or an affiliate) receives investment advisory fees from the Master Portfolio.

Expense Waivers and Reimbursements:The fees and expenses of the Master Portfolio’s trustees who are not “interested persons” of MIP, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Master Portfolio’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Master Portfolio. Each of BFA and BAL, as applicable, has contractually agreed to reimburse the Master Portfolio or provide an offsetting credit against the administration fees paid by the Master Portfolio in an amount equal to these independent expenses through April 30, 2021. For the year ended December 31, 2019, the amount waived and/or reimbursed was $385,791.

The Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees the Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the amount waived was $175,916.

The Manager has contractually agreed to waive its investment advisory fee with respect to any portion of the Master Portfolio’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through April 30, 2021. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees of MIP, or by a vote of a majority of the outstanding voting securities of the Master Portfolio. This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the Manager waived $2,158 in investment advisory fees pursuant to this arrangement.

Securities Lending:The U.S. Securities and Exchange Commission (“SEC”) has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The Master Portfolio is responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the Master Portfolio bears to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a 90 day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, the Master Portfolio retains 73.5% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, the Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 80% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Statement of Operations. For the year ended December 31, 2019, the Master Portfolio paid BTC $197,708 in total for securities lending agent services.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, the Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Master Portfolio’s investment policies and restrictions. The Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Master Portfolio are directors and/or officers of BlackRock or its affiliates.

Other Transactions: The Master Portfolio may purchase securities from, or sell securities to, an affiliated fund provided the affiliation is due solely to having a common investment adviser, common officers, or common trustees. For the year ended December 31, 2019, the purchase and sale transactions and any net realized gains (losses) with affiliated funds in compliance with Rule17a-7 under the 1940 Act were as follows:

Purchases		Sales		Net Realized Gain (Loss)
$	656,292,770	$	60,145,540	$	(29,208,341	)

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments, excluding short-term securities, were $1,567,674,746 and $668,088,798, respectively.

8. INCOME TAX INFORMATION

The Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

Tax cost	$	13,338,949,197
Gross unrealized appreciation	$	10,452,081,189
Gross unrealized depreciation		(460,320,838	)
Net unrealized appreciation	$	9,991,760,351

9. BANK BORROWINGS

MIP, on behalf of the Master Portfolio, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the Master Portfolio may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the Master Portfolio, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statement of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the Master Portfolio did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, the Master Portfolio invests in securities or other instruments and may enter into certain transactions, and such activities subject the Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. The Master Portfolio’s prospectus provides details of the risks to which the Master Portfolio is subject.

The Master Portfolio may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk: The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. The Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that the Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. The Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause the Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of the Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which the Master Portfolio invests.

Counterparty Credit Risk:The Master Portfolio may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolio manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which

NOTESTO FINANCIAL STATEMENTS 39

Notes to Financial Statements  (continued)

potentially expose the Master Portfolio to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolio’s exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Master Portfolio.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

With exchange-traded futures, there is less counterparty credit risk to the Master Portfolio since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, the Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists in exchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Master Portfolio.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolio through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm S&P 500 Index Master Portfolio

To the Board of Trustees of

Master Investment Portfolio and Investors of S&P 500 Index Master Portfolio

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of S&P 500 Index Master Portfolio (one of the series constituting Master Investment Portfolio, referred to hereafter as the “Master Portfolio”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statement of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Master Portfolio as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Master Portfolio’s management. Our responsibility is to express an opinion on the Master Portfolio’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolio in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 14, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING  FIRM 41

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of BlackRock Funds III and MIP, on behalf of iShares S&P 500 Index Fund, S&P 500 Index Master Portfolio, respectively met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration into in an issuer the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements: The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

TRUSTEEAND OFFICER INFORMATION 43

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015); President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate. (c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015. (d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex. (e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

TRUSTEEAND OFFICER INFORMATION 45

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge by calling(800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Distributor

BlackRock Investments, LLC

New York, NY 10022

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information

General Information

Householding

The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Fund at(800) 441-7762.

Availability of Quarterly Schedule of Investments

The Fund/Master Portfolio file their complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information onForm N-Q. The Fund’s/Master Portfolio’s Forms N-PORT andN-Q are available on the SEC’s website at sec.gov. The Fund’s/Master Portfolio’s FormN-Q may also be obtained upon request and without charge by calling(800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Fund/Master Portfolio use to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling(800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Fund/Master Portfolio voted proxies relating to securities held in the Fund’s/Master Portfolio’s portfolio during the most recent12-month period ended June 30 is available upon request and without charge (1) atblackrock.com; or by calling(800) 441-7762; and (2) on the SEC’s website at sec.gov.

BlackRock’s Mutual Fund Family

BlackRock offers a diverse lineup of open-end mutual funds crossing all investment styles and managed by experts in equity, fixed income andtax-exempt investing. Visitblackrock.com for more information.

Shareholder Privileges

Account Information

Call us at(800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visitblackrock.com for more information.

Automatic Investment Plans

Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.

Systematic Withdrawal Plans

Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.

Retirement Plans

Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.

ADDITIONAL INFORMATION 47

Additional Information  (continued)

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding theirnon-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personalnon-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose tonon-affiliated third parties anynon-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. Thesenon-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access tonon-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect thenon-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

48 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund’s current prospectus. Past performance results shown in this report should not be considered a representation of future performance. Investment returns and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Statements and other information herein are as dated and are subject to change.

SPSF-12/19-AR

DECEMBER 31, 2019

2019 Annual Report

BlackRock Funds III

· iShares U.S. Aggregate Bond Index Fund

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from BlackRock or from your financial intermediary, such as a broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

You may elect to receive all future reports in paper free of charge. If you hold accounts directly with BlackRock, you can call (800) 441-7762 to inform BlackRock that you wish to continue receiving paper copies of your shareholder reports. If you hold accounts through a financial intermediary, you can follow the instructions included with this disclosure, if applicable, or contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Please note that not all financial intermediaries may offer this service. Your election to receive reports in paper will apply to all funds advised by BlackRock Advisors, LLC, BlackRock Fund Advisors or their affiliates, or all funds held with your financial intermediary, as applicable.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive electronic delivery of shareholder reports and other communications by: (i) accessing the BlackRock website at blackrock.com/edelivery and logging into your accounts, if you hold accounts directly with BlackRock, or (ii) contacting your financial intermediary, if you hold accounts through a financial intermediary. Please note that not all financial intermediaries may offer this service.

Not FDIC Insured • May Lose Value • No Bank Guarantee

The Markets in Review

Dear Shareholder,

U.S. equities and bonds finished the last year of the decade with impressive returns, putting an exclamation point on a decade of strong performance despite the fears and doubts about the economy that were ultimately laid to rest with unprecedented monetary stimulus and a sluggish yet resolute performance from the U.S. economy. In many ways, it was fitting that the themes of 2019 — geopolitical uncertainty, fears of recession, and decisive monetary stimulus — put the capstone on a decade that was defined by grappling with these competing forces.

Equity and bond markets posted solid returns, particularly in the second half of the year, as investors began to realize that the U.S. economy was maintaining the modest yet steady growth that has characterized this economic cycle. U.S. large cap equities advanced the most, while equities at the high end of the risk spectrum — emerging markets and U.S. small cap — lagged while still posting solid returns.

Fixed-income securities played an important role in diversified portfolios by delivering strong returns amid economic uncertainty, as interest rates declined (and bond prices rose). Long-term bonds, particularly long-term Treasuries, generally posted the strongest returns, as inflation remained low. Investment-grade and high-yield corporate bonds also posted solid returns, as the credit fundamentals in corporate markets remained relatively solid.

As equity performance faltered in late 2018 and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted away from policies designed to decrease inflation in favor of renewed efforts to stimulate economic activity. The Fed left interest rates unchanged in January 2019, then reduced interest rates three times thereafter, starting in July 2019. Similarly, the Fed took measures to support liquidity in short-term lending markets. Following in the Fed’s footsteps, the European Central Bank announced aggressive economic stimulus measures, including lower interest rates and the return of its bond purchasing program. The Bank of Japan signaled a continuation of accommodative monetary policy, while China committed to looser credit conditions and an increase in fiscal spending.

The outpouring of global economic stimulus led to a sharp rally in risk assets throughout the world despite the headwind of rising geopolitical and trade tensions. Hopes continued to remain high as the current economic expansion became the longest in U.S. history.

Looking ahead, we believe U.S. economic growth will stabilize and gradually improve in 2020. The primary drivers of recent market performance — trade and monetary policies — could take a back seat to a nascent expansion in manufacturing and a recent uptick in global growth. The headwinds of policy uncertainty in 2019 could become tailwinds in 2020 due topro-cyclical policy shifts.

Overall, we favor increasing investment risk to benefit from the brighter outlook. In addition to having a positive view for equities overall, we favor emerging market equities over developed market equities. Increasing cyclical exposure through value-style investing and maintaining a meaningful emphasis on high-quality companies through quality factors also makes sense for diversified investors. In fixed income, government bonds continue to be important portfolio stabilizers, while emerging market bonds, particularly local currency bonds, offer relatively attractive income opportunities.

In this environment, investors need to think globally, extend their scope across a broad array of asset classes, and be nimble as market conditions change. We encourage you to talk with your financial advisor and visitblackrock.com for further insight about investing in today’s markets.

Sincerely,

Rob Kapito

President, BlackRock Advisors, LLC

Rob Kapito

President, BlackRock Advisors, LLC

Total Returns as of December 31, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	10.92%	31.49%
U.S. small cap equities (Russell 2000® Index)	7.30	25.52
International equities (MSCI Europe, Australasia, Far East Index)	7.01	22.01
Emerging market equities (MSCI Emerging Markets Index)	7.09	18.42
3-month Treasury bills (ICE BofAML3-Month U.S. Treasury Bill Index)	1.03	2.28
U.S. Treasury securities (ICE BofAML10-Year U.S. Treasury Index)	1.36	8.91
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	2.45	8.72
Tax-exempt municipal bonds (S&P Municipal Bond Index)	2.21	7.26
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.98	14.32
Past performance is no guarantee of future results. Index performance is shown for illustrative purposes only. You cannot invest directly in an index.

2 THIS PAGEISNOT PARTOF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summary		4
About Fund Performance		6
Disclosure of Expenses		6
Fund Financial Statements:
Statement of Assets and Liabilities		7
Statement of Operations		8
Statements of Changes in Net Assets		9
Fund Financial Highlights		10
Fund Notes to Financial Statements		14
Fund Report of Independent Registered Public Accounting Firm		18
Important Tax Information		18
Master Portfolio Information		19
Master Portfolio Financial Statements:
Schedule of Investments		20
Statement of Assets and Liabilities		60
Statement of Operations		61
Statements of Changes in Net Assets		62
Master Portfolio Financial Highlights		63
Master Portfolio Notes to Financial Statements		64
Master Portfolio Report of Independent Registered Public Accounting Firm		71
Statement Regarding Liquidity Risk Management Program		72
Trustee and Officer Information		73
Additional Information		77
Glossary of Terms Used in this Report		78

3

Fund Summary  as of December 31, 2019 iShares U.S. Aggregate Bond Index Fund

Investment Objective

iShares U.S. Aggregate Bond Index Fund’s (the “Fund”) investment objective is to seek to provide investment results that correspond to the total return performance of fixed-income securities in the aggregate, as represented by the Bloomberg Barclays U.S. Aggregate Bond Index (the “Index”).

Portfolio Management Commentary

How did the Fund perform?

For the 12-month period ended December 31, 2019, the Fund’s Institutional Shares returned 8.56%, Investor A Shares returned 8.39%, Class K Shares returned 8.71% and Investor P Shares returned 8.32%. For the same period, the Index returned 8.72%.

Returns for the Fund’s respective share classes differ from the Index based on individual share class expenses. The Fund invests all of its assets in U.S. Total Bond Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio.

Describe the market environment.

During the first quarter of 2019, the Fed’s dovish pivot contributed to a meaningful rebound in equity prices. In its January announcement, the Fed indicated that it would refrain from interest rate hikes for the foreseeable future, and provided a dovish assessment of U.S. economic conditions, as well as transparency surrounding balance sheet normalization. The Fed’s messaging reduced the market’s expectations for rising short-term rates, serving as a boon for both equities and bonds. In addition, despite a 35-day government shutdown and global economic weakness, the U.S. economy continued to exhibit a tight labor market, low inflation and slowing but stable growth. Less optimism was evident in the U.S. rates market. The pause in interest rate hikes by the Fed, coupled with lowered forecasts for growth, drove investors into longer-duration government bonds.

In the second quarter of 2019, the prospect of easier monetary policy buoyed equities broadly. In the June Federal Open Market Committee announcement, Fed Chair Powell stated that if trade tensions weigh on the committee’s economic outlook or should the shortfall of inflation from the target rate persist longer than expected, the Fed would provide more accommodation to sustain the expansion. In May, the U.S. administration threatened an increase in tariffs and protectionism against both China and Mexico. However, these threats did not materialize, and sentiment eased heading into the month end G-20 meeting. To close the first half of the year, there were signs of weaker U.S. economic conditions.

In the third quarter of 2019, global trade tensions were a key focus for investors. U.S. equities suffered their worst week of 2019 in early August based on the U.S. administration’s promise to impose 10% tariffs on all Chinese imports not already subject to 25% tariffs. However, U.S./China tensions ostensibly eased ahead of a new round of trade talks in October. Regarding U.S. monetary policy, the Fed lowered the target range for the federal funds rate at its July and September meetings. Additionally, survey-based U.S. economic indicators continued to soften within the manufacturing and consumer sectors, while economic data releases exhibited resilience.

In the fourth quarter of 2019, investor risk appetite was boosted by renewed expectations for a U.S./China trade deal, strong economic growth and looser monetary policy. U.S. services and employment sectors continued to be buoyant. Overall, supportive macroeconomic data and increased investor risk appetite drove a sell-off for Treasuries in the quarter as 10-year U.S. Treasury bond yields increased 26 basis points (0.26%) to 1.92%. Lastly, despite renewed strength in the U.S. economy, the Fed lowered the benchmark federal funds rate by 25 basis points to 1.75% in October, marking its third rate cut of 2019.

Describe recent portfolio activity.

During the period, the Master Portfolio maintained its objective of seeking to provide investment results that correspond to the total return performance of fixed-income securities in the aggregate, as represented by the Index. Other factors considered in security selection included transaction costs and maturity structure.

The Master Portfolio held a small portion of its assets in cash committed for pending transactions, which did not have a material impact on Fund performance during the period.

Describe portfolio positioning at period end.

The Master Portfolio remains positioned to attempt to match the risk characteristics of the Index, irrespective of the market’s future direction.

The views expressed reflect the opinions of BlackRock as of the date of this report and are subject to change based on changes in market, economic or other conditions. These views are not intended to be a forecast of future events and are no guarantee of future results.

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Fund Summary  as of December 31, 2019 (continued) iShares U.S. Aggregate Bond Index Fund

TOTAL RETURN BASED ON A $10,000 INVESTMENT

^(a)  Assuming transaction costs and other operating expenses, including administration fees, if any.

^(b)  The Fund invests all of its assets in the Master Portfolio. The Master Portfolio invests primarily in investment-grade U.S. Government securities and corporate bonds, as well as investment-grade mortgage-backed, asset-backed and commercial mortgage-backed securities.

^(c)  A widely recognized unmanaged market-capitalization weighted index, comprised of investment-grade corporate bonds rated BBB or better, mortgages and U.S. Treasury and U.S. Government agency issues with at least one year to maturity.

Performance Summary for the Period Ended December 31, 2019

										Average Annual Total Returns (a)
										1 Year						5 Years						10 Years
	Standardized 30-Day Yields			Unsubsidized 30-Day Yields			6-Month Total Returns			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge			w/o sales charge			w/sales charge
Institutional		2.25	%		2.24	%		2.33	%		8.56	%		N/A			2.87	%		N/A			3.56	%		N/A
Investor A		2.00			1.99			2.30			8.39			N/A			2.62			N/A			3.31			N/A
Class K		2.30			2.29			2.45			8.71			N/A			2.94			N/A			3.62			N/A
Investor P		1.92			1.91			2.22			8.32			3.98	%		2.62			1.79	%		3.31			2.89	%
Bloomberg Barclays U.S. Aggregate Bond Index		—			—			2.45			8.72			N/A			3.05			N/A			3.75			N/A

^(a)  Assuming maximum sales charges, if any. Average annual total returns with and without sales charges reflect reductions for distribution and service fees. See “About Fund Performance” on page 6 for a detailed description of share classes, including any related sales charges and fees, and how performance was calculated for certain share classes.

N/A — Not applicable as share class and index do not have a sales charge.

Past performance is not indicative of future results.

Performance results may include adjustments made for financial reporting purposes in accordance with U.S. generally accepted accounting principles.

Expense Example

	Actual						Hypothetical (b)
	Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Beginning Account Value (07/01/19)		Ending Account Value (12/31/19)		Expenses Paid During the Period (a)		Annualized Expense Ratio
Institutional	$	1,000.00	$	1,023.30	$	0.51	$	1,000.00	$	1,024.70	$	0.51		0.10	%
Investor A		1,000.00		1,023.00		1.78		1,000.00		1,023.44		1.79		0.35
Class K		1,000.00		1,024.50		0.26		1,000.00		1,024.95		0.26		0.05
Investor P		1,000.00		1,022.20		1.78		1,000.00		1,023.44		1.79		0.35

^(a) For each class of the Fund, expenses are equal to the annualized net expense ratio for the class, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period shown). Because the Fund invests all of its assets in the Master Portfolio, the expense example reflects the net expenses of both the Fund and the Master Portfolio.

^(b) Hypothetical 5% annual return before expenses is calculated by prorating the number of days in the most recent fiscal half year divided by 365.

See “Disclosure of Expenses” on page 6 for further information on how expenses were calculated.

FUND SUMMARY 5

About Fund Performance

Institutional and Class K Shares are not subject to any sales charge. These shares bear no ongoing distribution or service fees and are available only to certain eligible investors.

Investor A Sharesare not subject to any sales charge and bear no ongoing distribution fee. These shares are subject to an ongoing service fee of 0.25% per year. These shares are generally available through financial intermediaries.

Investor P Shares are subject to a maximum initial sales charge (front-end load) of 4.00% and a service fee of 0.25% per year (but no distribution fee). These shares are only available to investors purchasing shares through registered representatives of an insurance company’s broker-dealer that has entered into an agreement with the Fund’s distributor to offer such shares.

Prior to the inception date of March 31, 2011 for Institutional and Investor A Shares and prior to the inception date of August 6, 2018 for Investor P Shares, the performance of the classes is based on the returns of Class K Shares, adjusted to reflect the estimated annual fund fees and operating expenses of each respective share class of the Fund.

Performance information reflects past performance and does not guarantee future results. Current performance may be lower or higher than the performance data quoted. Refer toblackrock.com to obtain performance data current to the most recent month-end. Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. Figures shown in the performance table on the previous page assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend date. Investment return and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Distributions paid to each class of shares will vary because of the different levels of service, distribution and transfer agency fees applicable to each class, which are deducted from the income available to be paid to shareholders.

BlackRock Advisors, LLC (the “Administrator”), the Fund’s administrator, has contractually agreed to waive and/or reimburse a portion of the Fund’s expenses. Without such waiver and/or reimbursement, the Fund’s performance would have been lower. With respect to the Fund’s contractual waiver, the Administrator is under no obligation to continue waiving and/or reimbursing its fees after the applicable termination date of such agreement. See Note 4 of the Notes to Financial Statements for additional information on waivers and/or reimbursements.

The standardized 30-day yield includes the effects of any waivers and/or reimbursements. The unsubsidized 30-day yield excludes the effects of any waivers and/or reimbursements.

Disclosure of Expenses

Shareholders of the Fund may incur the following charges: (a) transactional expenses, such as sales charges, and (b) operating expenses, including administration fees, service and distribution fees, including12b-1 fees, acquired fund fees and expenses, and other fund expenses. The expense example shown on the previous page (which is based on a hypothetical investment of $1,000 invested on July 1, 2019 and held through December 31, 2019) is intended to assist shareholders both in calculating expenses based on an investment in the Fund and in comparing these expenses with similar costs of investing in other mutual funds.

The expense example provides information about actual account values and actual expenses. In order to estimate the expenses a shareholder paid during the period covered by this report, shareholders can divide their account value by $1,000 and then multiply the result by the number corresponding to their Fund and share class under the heading entitled “Expenses Paid During the Period.”

The expense example also provides information about hypothetical account values and hypothetical expenses based on the Fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses. In order to assist shareholders in comparing the ongoing expenses of investing in the Fund and other funds, compare the 5% hypothetical example with the 5% hypothetical examples that appear in shareholder reports of other funds.

The expenses shown in the expense example are intended to highlight shareholders’ ongoing costs only and do not reflect transactional expenses, such as sales charges, if any. Therefore, the hypothetical example is useful in comparing ongoing expenses only, and will not help shareholders determine the relative total expenses of owning different funds. If these transactional expenses were included, shareholder expenses would have been higher.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	iShares U.S. Aggregate Bond Index Fund
ASSETS
Investments at value — Master Portfolio	$	2,042,840,489
Receivables:
Capital shares sold		10,955,607
Withdrawals from the Master Portfolio		644,602
Total assets		2,054,440,698
LIABILITIES
Payables:
Administration fees		58,039
Capital shares redeemed		11,600,209
Other accrued expenses		12,199
Service fees		26,214
Total liabilities		11,696,661
NET ASSETS	$	2,042,744,037
NET ASSETS CONSIST OF
Paid-in capital	$	1,986,751,072
Accumulated earnings		55,992,965
NET ASSETS	$	2,042,744,037
NET ASSET VALUE
Institutional — Based on net assets of $187,854,363 and 18,076,935 shares outstanding, unlimited shares authorized, no par value	$	10.39
Investor A — Based on net assets of $121,421,096 and 11,685,337 shares outstanding, unlimited shares authorized, no par value	$	10.39
Class K — Based on net assets of $1,730,754,162 and 166,449,481 shares outstanding, unlimited shares authorized, no par value	$	10.40
Investor P — Based on net assets of $2,714,416 and 261,253 shares outstanding, unlimited shares authorized, no par value	$	10.39

See notes to financial statements.

FINANCIAL STATEMENTS 7

Statement of Operations

Year Ended December 31, 2019

	iShares U.S. Aggregate Bond Index Fund
INVESTMENT INCOME
Net investment income allocated from the Master Portfolio:
Dividends — affiliated	$	2,752,562
Interest — unaffiliated		44,792,120
Securities lending income — affiliated — net		748,141
Other income — affiliated		96,674
Expenses		(692,421	)
Fees waived		114,177
Total investment income		47,811,253
FUND EXPENSES
Service — class specific		317,539
Administration — class specific		317,352
Professional		12,195
Miscellaneous		1,500
Total expenses		648,586
Less fees waived and/or reimbursed by the Administrator/Manager		(12,195	)
Total expenses after fees waived and/or reimbursed		636,391
Net investment income		47,174,862
REALIZED AND UNREALIZED GAIN ALLOCATED FROM THE MASTER PORTFOLIO
Net realized gain from investments		4,247,078
Net change in unrealized appreciation on investments		77,964,427
Net realized and unrealized gain		82,211,505
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	129,386,367

See notes to financial statements.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	iShares U.S. Aggregate Bond Index Fund
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	47,174,862		$	30,533,343
Net realized gain (loss)		4,247,078			(6,817,144	)
Net change in unrealized appreciation (depreciation)		77,964,427			(19,188,696	)
Net increase in net assets resulting from operations		129,386,367			4,527,503
DISTRIBUTIONS TO SHAREHOLDERS(a)
From net investment income:
Institutional		(5,169,750	)		(3,320,182	)
Investor A		(3,287,319	)		(3,016,684	)
Class K		(39,979,544	)		(24,785,155	)
Investor P		(33,347	)		(2,339	)
From return of capital:
Institutional		—			(1,793	)
Investor A		—			(1,629	)
Class K		—			(13,384	)
Investor P		—			(1	)
Decrease in net assets resulting from distributions to shareholders		(48,469,960	)		(31,141,167	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		656,733,017			354,852,563
NET ASSETS
Total increase in net assets		737,649,424			328,238,899
Beginning of year		1,305,094,613			976,855,714
End of year	$	2,042,744,037		$	1,305,094,613

^(a)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

See notes to financial statements.

FINANCIAL STATEMENTS 9

Financial Highlights

(For a share outstanding throughout each period)

	iShares U.S. Aggregate Bond Index Fund
	Institutional
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.85		$	10.13		$	10.02		$	9.99		$	10.17
Net investment income(a)		0.29			0.26			0.22			0.20			0.19
Net realized and unrealized gain (loss)		0.54			(0.28	)		0.11			0.05			(0.16	)
Net increase (decrease) from investment operations		0.83			(0.02	)		0.33			0.25			0.03
Distributions(b)
From net investment income		(0.29	)		(0.26	)		(0.22	)		(0.21	)		(0.19	)
From net realized gain		—			—			—			(0.01	)		(0.02	)
From return of capital		—			(0.00	)(c)		—			(0.00	)(c)		—
Total distributions		(0.29	)		(0.26	)		(0.22	)		(0.22	)		(0.21	)
Net asset value, end of year	$	10.39		$	9.85		$	10.13		$	10.02		$	9.99
Total Return(d)
Based on net asset value		8.56	%(e)		(0.13	)%		3.34	%		2.48	%		0.33	%
Ratios to Average Net Assets(f)(g)
Total expenses		0.10	%		0.09	%		0.09	%		0.10	%		0.12	%
Total expenses after fees waived and/or reimbursed		0.10	%		0.09	%		0.09	%		0.10	%		0.11	%
Net investment income		2.85	%		2.67	%		2.15	%		1.95	%		1.85	%
Supplemental Data
Net assets, end of year (000)	$	187,854		$	150,714		$	98,927		$	116,473		$	58,043
Portfolio turnover rate of the Master Portfolio(h)		158	%		274	%		345	%		278	%		356	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which had no impact on the Fund’s total return.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(g)  Includes the Fund’s share of its corresponding Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%
Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%

^(h)  Includes mortgage dollar roll transactions (“MDRs”). Additional information regarding portfolio turnover rate is as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Portfolio turnover rate(excluding MDRs)		97	%		162	%		193	%		164	%		300	%

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares U.S. Aggregate Bond Index Fund
	Investor A
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.84		$	10.13		$	10.01		$	9.99		$	10.17
Net investment income(a)		0.26			0.24			0.19			0.17			0.16
Net realized and unrealized gain (loss)		0.56			(0.29	)		0.13			0.05			(0.15	)
Net increase (decrease) from investment operations		0.82			(0.05	)		0.32			0.22			0.01
Distributions(b)
From net investment income		(0.27	)		(0.24	)		(0.20	)		(0.19	)		(0.17	)
From net realized gain		—			—			—			(0.01	)		(0.02	)
From return of capital		—			(0.00	)(c)		—			(0.00	)(c)		—
Total distributions		(0.27	)		(0.24	)		(0.20	)		(0.20	)		(0.19	)
Net asset value, end of year	$	10.39		$	9.84		$	10.13		$	10.01		$	9.99
Total Return(d)
Based on net asset value		8.39	%(e)		(0.48	)%		3.19	%		2.14	%		0.08	%
Ratios to Average Net Assets(f)(g)
Total expenses		0.35	%		0.34	%		0.34	%		0.35	%		0.37	%
Total expenses after fees waived and/or reimbursed		0.35	%		0.34	%		0.34	%		0.35	%		0.36	%
Net investment income		2.61	%		2.39	%		1.91	%		1.69	%		1.61	%
Supplemental Data
Net assets, end of year (000)	$	121,421		$	126,483		$	121,690		$	71,391		$	19,145
Portfolio turnover rate of the Master Portfolio(h)		158	%		274	%		345	%		278	%		356	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which had no impact on the Fund’s total return.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(g)  Includes the Fund’s share of its corresponding Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%
Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%

^(h)  Includes mortgage dollar roll transactions (“MDRs”). Additional information regarding portfolio turnover rate is as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Portfolio turnover rate(excluding MDRs)		97	%		162	%		193	%		164	%		300	%

See notes to financial statements.

FINANCIAL HIGHLIGHTS 11

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares U.S. Aggregate Bond Index Fund
	Class K
	Year Ended December 31,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	9.85		$	10.13		$	10.02		$	9.99		$	10.17
Net investment income(a)		0.29			0.27			0.22			0.20			0.19
Net realized and unrealized gain (loss)		0.56			(0.28	)		0.12			0.06			(0.15	)
Net increase (decrease) from investment operations		0.85			(0.01	)		0.34			0.26			0.04
Distributions(b)
From net investment income		(0.30	)		(0.27	)		(0.23	)		(0.22	)		(0.20	)
From net realized gain		—			—			—			(0.01	)		(0.02	)
From return of capital		—			(0.00	)(c)		—			(0.00	)(c)		—
Total distributions		(0.30	)		(0.27	)		(0.23	)		(0.23	)		(0.22	)
Net asset value, end of year	$	10.40		$	9.85		$	10.13		$	10.02		$	9.99
Total Return(d)
Based on net asset value		8.71	%(e)		(0.08	)%		3.39	%		2.53	%		0.38	%
Ratios to Average Net Assets(f)(g)
Total expenses		0.05	%		0.04	%		0.04	%		0.05	%		0.07	%
Total expenses after fees waived and/or reimbursed		0.05	%		0.04	%		0.04	%		0.05	%		0.06	%
Net investment income		2.89	%		2.71	%		2.21	%		2.00	%		1.89	%
Supplemental Data
Net assets, end of year (000)	$	1,730,754		$	1,027,621		$	756,239		$	445,650		$	166,203
Portfolio turnover rate of the Master Portfolio(h)		158	%		274	%		345	%		278	%		356	%

^(a)  Based on average shares outstanding.

^(b)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(c)  Amount is greater than $(0.005) per share.

^(d)  Where applicable, assumes the reinvestment of distributions.

^(e)  Includes payment received from an affiliate, which had no impact on the Fund’s total return.

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

^(g)  Includes the Fund’s share of its corresponding Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Allocated fees waived		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%
Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%

^(h)  Includes mortgage dollar roll transactions (“MDRs”). Additional information regarding portfolio turnover rate is as follows:

	Year Ended December 31,
	2019			2018			2017			2016			2015
Portfolio turnover rate(excluding MDRs)		97	%		162	%		193	%		164	%		300	%

See notes to financial statements.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	iShares U.S. Aggregate Bond Index Fund
	Investor P
	Year Ended December 31, 2019			Period from 08/06/18 (a) to 12/31/18
Net asset value, beginning of period	$	9.85		$	9.83
Net investment income(b)		0.27			0.10
Net realized and unrealized gain		0.54			0.03
Net increase from investment operations		0.81			0.13
Distributions(c)
From net investment income		(0.27	)		(0.11	)
From return of capital		—			(0.00	)(d)
Total distributions		(0.27	)		(0.11	)
Net asset value, end of period	$	10.39		$	9.85
Total Return(e)
Based on net asset value		8.32	%(f)		1.30	%(g)
Ratios to Average Net Assets(h)(i)
Total expenses		0.35	%		0.34	%(j)
Total expenses after fees waived and/or reimbursed		0.35	%		0.34	%(j)
Net investment income		2.54	%		2.61	%(j)
Supplemental Data
Net assets, end of period (000)	$	2,714		$	277
Portfolio turnover rate of the Master Portfolio(k)		158	%		274	%

^(a)  Commencement of operations.

^(b)  Based on average shares outstanding.

^(c)  Distributions for annual periods determined in accordance with U.S. federal income tax regulations.

^(d)  Amount is greater than $(0.005) per share.

^(e)  Where applicable, excludes the effects of any sales charges and assumes the reinvestment of distributions.

^(f)  Includes payment received from an affiliate, which had no impact on the Fund’s total return.

^(g)  Aggregate total return.

^(h)  Includes the Fund’s share of the Master Portfolio’s allocated expenses and/or net investment income.

⁽ⁱ⁾  Includes the Fund’s share of its corresponding Master Portfolio’s allocated fees waived and expenses and/or net investment income. Excludes expenses incurred indirectly as a result of the Master Portfolio’s investments in underlying funds as follows:

	Year Ended December 31, 2019			Period from 08/06/18 (a) to 12/31/18
Allocated fees waived		0.01	%		0.01	%
Investments in underlying funds		0.01	%		0.01	%

^(j)  Annualized.

^(k)  Includes mortgage dollar roll transactions (“MDRs”). Additional information regarding portfolio turnover rate is as follows:

	Year Ended December 31, 2019			Period from 08/06/18 (a) to 12/31/18
Portfolio turnover rate(excluding MDRs)		97	%		162	%

See notes to financial statements.

FINANCIAL HIGHLIGHTS 13

Notes to Financial Statements

1. ORGANIZATION

BlackRock Funds III (the “Trust”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. The Trust is organized as a Delaware statutory trust. iShares U.S. Aggregate Bond Index Fund (the “Fund”) is a series of the Trust. The Fund is classified as diversified.

The Fund seeks to achieve its investment objective by investing all of its assets in U.S. Total Bond Index Master Portfolio (the “Master Portfolio”), a series of Master Investment Portfolio (“MIP”), an affiliate of the Trust, which has the same investment objective and strategies as the Fund. The value of the Fund’s investment in the Master Portfolio reflects the Fund’s proportionate interest in the net assets of the Master Portfolio. The performance of the Fund is directly affected by the performance of the Master Portfolio. At December 31, 2019, the percentage of the Master Portfolio owned by the Fund was 18.27%. The financial statements of the Master Portfolio, including the Schedule of Investments, are included elsewhere in this report and should be read in conjunction with the Fund’s financial statements.

The Fund offers multiple classes of shares. All classes of shares have identical voting, dividend, liquidation and other rights and are subject to the same terms and conditions, except that certain classes bear expenses related to the shareholder servicing and distribution of such shares. Institutional and Class K Shares are sold without a sales charge and only to certain eligible investors. Investor A and Investor P Shares bear certain expenses related to shareholder servicing of such shares. Investor A Shares are generally available through financial intermediaries. Investor P Shares are only available through registered representatives of an insurance company’s broker-dealer that has entered into an agreement with the Fund’s distributor to offer such shares. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures.

Share Class	Initial Sales Charge	CDSC			Conversion Privilege
Institutional, Investor A and Class K Shares	No		No		None
Investor P Shares	Yes		No	(a)	None

^(a)  Investor P Shares may be subject to a contingent deferred sales charge (“CDSC”) for certain redemptions where no initial sales charge was paid at the time of purchase.

The Board of Trustees of the Trust and Board of Trustees of MIP are referred to throughout this report as the “Board of Trustees” or the “Board” and the members are referred to as “Trustees.”

The Fund, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Fund is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, contributions to and withdrawals from the Master Portfolio are accounted for on a trade date basis. The Fund records its proportionate share of the Master Portfolio’s income, expenses and realized and unrealized gains and losses on a daily basis. Realized and unrealized gains and losses are adjusted utilizing partnership tax allocation rules. In addition, the Fund accrues its own expenses. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

Distributions: Distributions from net investment income are declared daily and paid monthly. Distributions of capital gains are recorded on theex-dividend date and made at least annually. The portion of distributions, if any, that exceeds a fund’s current and accumulated earnings and profits, as measured on a tax basis, constitutes anon-taxable return of capital. The character and timing of distributions are determined in accordance with U.S. federal income tax regulations, which may differ from U.S. GAAP.

Indemnifications:In the normal course of business, the Fund enters into contracts that contain a variety of representations that provide general indemnification. The Fund’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Fund, which cannot be predicted with any certainty.

Other: Expenses directly related to the Fund or its classes are charged to the Fund or the applicable class. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods. Expenses directly related to the Fund and other shared expenses prorated to the Fund are allocated daily to each class based on its relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Fund’s policy is to value its financial instruments at fair value. The Fund records its investment in the Master Portfolio at fair value based on the Fund’s proportionate interest in the net assets of the Master Portfolio. Valuation of securities held by the Master Portfolio is discussed in Note 3 of the Master Portfolio’s Notes to Financial Statements, which are included elsewhere in this report.

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

4. ADMINISTRATION AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Administration:The Trust, on behalf of the Fund, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the Fund’s ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Fund. BAL is entitled to receive for these administrative services an annual fee based on the average daily net assets of the Fund as follows:

Institutional		Investor A		Class K		Investor P
	0.06%		0.06%		0.01%		0.06%

For the year ended December 31, 2019, the following table shows the class specific administration fees borne directly by each share class of the Fund:

Institutional		Investor A		Class K		Investor P		Total
$	107,104	$	75,495	$	134,063	$	690	$	317,352

From time to time, BAL may waive such fees in whole or in part. Any such waiver will reduce the expenses of the Fund and, accordingly, have a favorable impact on its performance. BAL may delegate certain of its administration duties tosub-administrators. For the year ended December 31, 2019, BAL did not waive any amount.

Service and Distribution Fees: The Trust, on behalf of the Fund, entered into a Distribution Agreement and a Distribution and Service Plan with BlackRock Investments, LLC (“BRIL”), an affiliate of the Administrator. Pursuant to the Distribution and Service Plan and in accordance with Rule12b-1 under the 1940 Act, the Fund pays BRIL ongoing service fees. The fees are accrued daily and paid monthly at an annual rate of 0.25% based upon the average daily net assets of Investor A Shares and Investor P Shares.

BRIL and broker-dealers, pursuant tosub-agreements with BRIL, provide shareholder servicing and distribution services to the Fund. The ongoing service and/or distribution fee compensates/reimburses BRIL and each broker-dealer for providing shareholder servicing and/or distribution related services to shareholders.

For the year ended December 31, 2019, the following table shows the class specific service fees borne directly by each share class of the Fund:

Investor A		Investor P		Total
$	314,649	$	2,890	$	317,539

Other Fees:For the year ended December 31, 2019, affiliates earned underwriting discounts, direct commissions and dealer concessions on sales of the Fund’s Investor P Shares, which totaled $1,834.

For the year ended December 31, 2019, affiliates received CDSCs of $72 for Investor P Shares.

Expense Limitations, Waivers, Reimbursements, and Recoupments:The fees and expenses of the Trust’s trustees who are not “interested persons” of the Trust, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Trust’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Fund. Each of BAL and BFA, as applicable, has contractually agreed to reimburse the Fund or provide an offsetting credit against the administration fees paid by the Fund in an amount equal to these independent expenses through April 30, 2020. For the year ended December 31, 2019, the amount waived was $12,195.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the U.S. Securities and Exchange Commission (“SEC”), the Fund may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Fund’s investment policies and restrictions. The Fund is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Fund did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Trust are directors and/or officers of BlackRock or its affiliates.

5. INCOME TAX INFORMATION

It is the Fund’s policy to comply with the requirements of the Internal Revenue Code of 1986, as amended, applicable to regulated investment companies, and to distribute substantially all of its taxable income to its shareholders. Therefore, no U.S. federal income tax provision is required.

The Fund files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Fund’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Fund’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

NOTESTO FINANCIAL STATEMENTS 15

Notes to Financial Statements  (continued)

Management has analyzed tax laws and regulations and their application to the Fund as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Fund’s financial statements.

The tax character of distributions paid was as follows:

	12/31/19		12/31/18
Ordinary income	$	48,469,960	$	31,124,360
Return of capital		—		16,807
	$	48,469,960	$	31,141,167

As of period end, the tax components of accumulated earnings were as follows:

Undistributed ordinary income	$	9,322
Non-expiring Capital loss carryforwards(a)		(6,508,092	)
Net unrealized gains(b)		62,491,735
	$	55,992,965

^(a)  Amounts available to offset future realized capital gains.

^(b)  The difference between book-basis andtax-basis net unrealized gains was attributable primarily to the timing and recognition of partnership income.

During the year ended December 31, 2019, the Fund utilized $2,880,973 of its capital loss carryforward.

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended 12/31/19						Year Ended 12/31/18
	Shares			Amount			Shares			Amount
Institutional
Shares sold		17,058,082		$	172,024,769			10,611,905		$	103,995,282
Shares issued in reinvestment of distributions		504,982			5,169,750			338,915			3,320,601
Shares redeemed		(14,794,426	)		(149,308,238	)		(5,410,391	)		(53,156,868	)
Net increase		2,768,638		$	27,886,281			5,540,429		$	54,159,015
Investor A
Shares sold		6,256,906		$	63,943,486			7,603,618		$	74,842,788
Shares issued in reinvestment of distributions		320,092			3,277,425			307,740			3,018,107
Shares redeemed		(7,741,876	)		(79,075,805	)		(7,079,417	)		(69,658,569	)
Net increase (decrease)		(1,164,878	)	$	(11,854,894	)		831,941		$	8,202,326
Class K
Shares sold		93,270,582		$	957,362,242			65,903,541		$	647,766,551
Shares issued in reinvestment of distributions		3,642,925			37,420,389			2,464,274			24,169,734
Shares redeemed		(34,792,319	)		(356,492,335	)		(38,677,132	)		(379,721,218	)
Net increase		62,121,188		$	638,290,296			29,690,683		$	292,215,067
							Period from 08/06/18 (a) to 12/31/18
Investor P
Shares sold		251,721		$	2,603,182			28,116		$	275,976
Shares issued in reinvestment of distributions		2,681			27,817			19			187
Shares redeemed		(21,283	)		(219,665	)		(1	)		(8	)
Net increase		233,119		$	2,411,334			28,134		$	276,155
Total Net Increase		63,958,067		$	656,733,017			36,091,187		$	354,852,563

^(a) Commencement of operations

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

As of December 31, 2019, BlackRock Financial Management, Inc., an affiliate of the Fund, owned 20,346 Investor P Shares of the Fund.

7. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Fund through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 17

Report of Independent Registered Public Accounting Firm iShares U.S. Aggregate Bond Index Fund

To the Board of Trustees of

BlackRock Funds III and Shareholders of iShares U.S. Aggregate Bond Index Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities of iShares U.S. Aggregate Bond Index Fund (one of the series constituting BlackRock Funds III, referred to hereafter as the “Fund”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the periods indicated therein (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the periods indicated therein in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the administrator of the Master Portfolio. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

Important Tax Information  (unaudited)

During the fiscal year ended December 31, 2019, the following information is provided with respect to the ordinary income distributions paid by the Fund:

Federal Obligation Interest(a)	31.42%
Interest-Related Dividends for Non-U.S. Residents(b)	83.10

^(a)  The law varies in each state as to whether and what percentage of dividend income attributable to federal obligations is exempt from state income tax. We recommend that you consult your tax advisor to determine if any portion of the dividends you received is exempt from state income taxes.

^(b) Represents the portion of the taxable ordinary income dividends eligible for exemption from U.S. withholding tax for nonresident aliens and foreign corporations.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Master Portfolio Information  as of December 31, 2019 U.S. Total Bond Index Master Portfolio

PORTFOLIO COMPOSITION

Asset Type	Percent of Total Investments
U.S. Treasury Obligations		34	%
U.S. Government Sponsored Agency Securities		25
Corporate Bonds		21
Foreign Agency Obligations		3
Non-Agency Mortgage-Backed Securities		1
Municipal Bonds		1
Asset-Backed Securities		—	(a)
Preferred Securities		—	(a)
Short-Term Securities		16
TBA Sale Commitments		(1	)

^(a)  Represents less than 1%.

CREDIT QUALITY ALLOCATION ^(b)

Credit Rating	Percent of Total Investments (c)
AAA/Aaa(d)		73	%
AA/Aa		4
A		12
BBB/Baa		11
N/R		—	(a)

^(b)  For financial reporting purposes, credit quality ratings shown above reflect the highest rating assigned by either S&P Global Ratings or Moody’s Investors Service. These rating agencies are independent, nationally recognized statistical rating organizations and are widely used. Investment grade ratings are credit ratings of BBB/Baa or higher. Below investment grade ratings are credit ratings of BB/Ba or lower. Investments designated N/R are not rated by either rating agency. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change.

^(c) Excludes short-term securities.

^(d) The investment adviser evaluates the credit quality of not-rated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuer. Using this approach, the investment adviser has deemed U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations as AAA/Aaa.

MASTER PORTFOLIO INFORMATION 19

Schedule of Investments December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Asset-Backed Securities — 0.5%
American Express Credit Account Master Trust,Series 2019-1, Class A, 2.87%, 10/15/24	$	4,530	$	4,628,403
Americredit Automobile Receivables Trust,Series 2018-1, Class D, 3.82%, 03/18/24		4,000		4,139,715
Citibank Credit Card Issuance Trust:
Series2014-A5, Class A5, 2.68%, 06/07/23		6,870		6,950,340
Series2016-A2, Class A2, 2.19%, 11/20/23		9,750		9,805,525
Series2017-A3, Class A3, 1.92%, 04/07/22		3,600		3,599,807
Ford Credit Auto Owner Trust,Series 2017-C, Class A4, 2.16%, 03/15/23		3,250		3,259,736
Honda Auto Receivables Owner Trust,Series 2017-4, Class A4, 2.21%, 03/21/24		6,525		6,548,834
Nissan Auto Receivables2019-B Owner Trust,Series 2019-B, Class A4, 2.54%, 12/15/25		6,000		6,098,830
Synchrony Credit Card Master Note Trust, Class A:
Series2015-1, 2.37%, 03/15/23		3,000		3,002,336
Series2018-2, 3.47%, 05/15/26		3,415		3,565,988
Total Asset-Backed Securities — 0.5% (Cost — $50,752,493)				51,599,514
Corporate Bonds — 25.5%
Aerospace & Defense — 0.4%
Boeing Co.:
2.30%, 08/01/21(a)		300		301,698
2.35%, 10/30/21		75		75,729
2.13%, 03/01/22		250		250,670
1.88%, 06/15/23(a)		500		496,875
2.70%, 02/01/27		230		233,199
2.80%, 03/01/27		1,000		1,016,216
3.20%, 03/01/29(a)		1,000		1,042,921
2.95%, 02/01/30(a)		570		583,472
6.13%, 02/15/33(a)		100		130,487
3.25%, 02/01/35		600		614,078
3.30%, 03/01/35		65		65,266
3.38%, 06/15/46		250		244,329
3.85%, 11/01/48		1,000		1,062,384
3.90%, 05/01/49(a)		750		814,233
3.75%, 02/01/50(a)		540		574,299
3.95%, 08/01/59		500		534,091
Embraer Netherlands Finance BV:
5.05%, 06/15/25		250		273,906
5.40%, 02/01/27(a)		500		563,438
General Dynamics Corp.:
3.00%, 05/11/21		3,000		3,050,488
3.88%, 07/15/21(a)		50		51,359
2.25%, 11/15/22		500		505,366
3.38%, 05/15/23		500		522,448
3.50%, 05/15/25		1,000		1,071,675
2.13%, 08/15/26		500		495,939
3.75%, 05/15/28		500		550,550
L3Harris Technologies, Inc.:
3.83%, 04/27/25		500		533,625
4.85%, 04/27/35(a)		1,065		1,257,354
4.95%, 02/15/21(a)(b)		250		256,147
4.40%, 06/15/28(b)		250		278,727
2.90%, 12/15/29		200		203,175
Lockheed Martin Corp.:
3.35%, 09/15/21		1,000		1,025,054
3.55%, 01/15/26		2,250		2,413,931
3.60%, 03/01/35(a)		65		71,080
4.07%, 12/15/42		100		114,199
3.80%, 03/01/45		1,500		1,666,109

Security	Par (000)		Value
Aerospace & Defense (continued)
4.70%, 05/15/46	$	750	$	953,677
4.09%, 09/15/52(a)		500		586,696
Northrop Grumman Corp.:
3.25%, 08/01/23(a)		500		521,275
2.93%, 01/15/25(a)		1,000		1,031,200
3.25%, 01/15/28		2,000		2,087,338
4.75%, 06/01/43(a)		375		453,263
4.03%, 10/15/47(a)		1,500		1,675,640
Raytheon Co.:
4.88%, 10/15/40(a)		250		313,449
4.70%, 12/15/41		100		124,000
Rockwell Collins, Inc.:
2.80%, 03/15/22		1,000		1,017,605
3.50%, 03/15/27		1,000		1,062,145
4.35%, 04/15/47		1,000		1,177,739
United Technologies Corp.:
3.35%, 08/16/21		400		409,599
1.95%, 11/01/21		250	��	250,545
3.10%, 06/01/22		600		615,624
3.65%, 08/16/23		1,250		1,318,009
2.65%, 11/01/26(a)		1,000		1,023,854
3.13%, 05/04/27(a)		1,000		1,049,399
4.13%, 11/16/28(a)		3,000		3,375,282
4.45%, 11/16/38(a)		500		591,683
5.70%, 04/15/40(a)		300		403,948
4.50%, 06/01/42(a)		1,700		2,038,167
4.15%, 05/15/45		500		573,508
3.75%, 11/01/46		750		817,324
4.05%, 05/04/47		500		573,575
4.63%, 11/16/48		1,250		1,566,473
				48,555,534
Air Freight & Logistics — 0.1%
FedEx Corp.:
4.00%, 01/15/24(a)		250		267,539
3.25%, 04/01/26(a)		545		567,257
3.30%, 03/15/27		500		517,057
3.10%, 08/05/29(a)		1,000		999,291
3.90%, 02/01/35		190		193,694
3.88%, 08/01/42(a)		50		48,236
4.75%, 11/15/45		160		168,502
4.55%, 04/01/46		750		771,464
4.40%, 01/15/47		500		502,305
4.05%, 02/15/48		1,000		966,225
4.95%, 10/17/48		1,000		1,093,258
United Parcel Service, Inc.:
3.13%, 01/15/21		500		505,969
2.05%, 04/01/21		500		501,339
2.45%, 10/01/22		500		508,016
2.50%, 04/01/23(a)		2,000		2,036,805
2.40%, 11/15/26(a)		2,000		2,022,028
3.05%, 11/15/27		500		525,981
6.20%, 01/15/38(a)		100		139,311
3.63%, 10/01/42		250		255,526
3.40%, 11/15/46(a)		220		219,462
3.75%, 11/15/47(a)		500		538,835
4.25%, 03/15/49		1,000		1,171,366
3.40%, 09/01/49		300		303,980
				14,823,446
Airlines — 0.1%
American Airlines Pass-Through Trust:
Series2013-2, Class A, 4.95%, 07/15/24		99		103,539
Series2016-2, Class AA, 3.20%, 12/15/29		427		439,388
Series2019-1, Class AA, 3.15%, 08/15/33		1,000		1,028,219

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Airlines (continued)
Continental Airlines Pass-Through Trust,Series 2012-1, Class A, 4.15%, 10/11/25	$	34	$	35,729
Continental Airlines, Inc. Pass Through Trust,Series 2-A, 4.00%, 04/29/26		350		369,032
Delta Air Lines Pass-Through Trust,Series 2019-1, Class AA, 3.20%, 10/25/25		1,000		1,040,253
Delta Air Lines, Inc., 3.75%, 10/28/29		1,000		998,410
JetBlue2019-1 Class AA Pass Through Trust, Series AA, 2.75%, 11/15/33(a)		940		951,840
United Airlines Pass-Through Trust:
Series2013-1, Class A, 4.30%, 02/15/27		151		161,320
Series2016-1, Class AA, 3.10%, 01/07/30		447		458,273
Series AA, 2.70%, 11/01/33		1,350		1,355,255
US Airways Pass Through Trust,Series 2013-1 Class A, 3.95%, 05/15/27		163		171,545
				7,112,803
Auto Components — 0.1%
American Honda Finance Corp.:
1.65%, 07/12/21(a)		750		748,269
1.95%, 05/20/22		300		301,089
2.05%, 01/10/23		895		898,428
3.63%, 10/10/23		2,000		2,112,076
2.40%, 06/27/24(a)		1,000		1,011,192
2.15%, 09/10/24		1,000		1,000,788
2.30%, 09/09/26		1,000		998,241
Aptiv PLC, 4.40%, 10/01/46(a)		500		481,962
BorgWarner, Inc., 3.38%, 03/15/25		70		73,240
Daimler Finance North America LLC, 8.50%, 01/18/31		600		893,041
Lear Corp., 4.25%, 05/15/29		1,000		1,033,702
PACCAR Financial Corp., 2.00%, 09/26/22		2,180		2,192,390
Toyota Motor Corp.:
2.36%, 07/02/24		500		507,085
2.76%, 07/02/29		185		189,833
Toyota Motor Credit Corp., 2.00%, 10/07/24		3,000		3,000,406
				15,441,742
Automobiles — 0.1%
Ford Motor Co.:
4.35%, 12/08/26		750		774,989
7.45%, 07/16/31		150		178,269
4.75%, 01/15/43		1,850		1,644,231
5.29%, 12/08/46		500		476,447
General Motors Co.:
4.88%, 10/02/23		600		643,955
4.00%, 04/01/25(a)		2,000		2,108,491
4.20%, 10/01/27		2,000		2,091,787
5.00%, 04/01/35		750		775,292
6.60%, 04/01/36(a)		250		295,075
5.15%, 04/01/38		500		511,492
5.20%, 04/01/45		250		252,501
6.75%, 04/01/46		275		322,610
5.40%, 04/01/48		500		517,849
5.95%, 04/01/49		1,000		1,108,612
				11,701,600
Banks — 2.7%
Australia & New Zealand Banking Group Ltd.:
3.30%, 05/17/21		1,000		1,019,541
2.30%, 06/01/21		1,000		1,005,411
2.05%, 11/21/22		1,705		1,711,064
Bancolombia SA, 5.95%, 06/03/21		100		105,000
Bank of Montreal:
2.35%, 09/11/22(a)		2,000		2,027,195

Security	Par (000)		Value
Banks (continued)
2.50%, 06/28/24	$	1,000	$	1,012,399
Series D, 3.10%, 04/13/21		1,000		1,016,333
Series E, 3.30%, 02/05/24(a)		4,000		4,169,606
Bank of New York Mellon Corp.:
2.50%, 04/15/21		250		251,729
2.05%, 05/03/21		500		501,591
3.55%, 09/23/21		50		51,372
2.60%, 02/07/22		1,000		1,015,207
1.95%, 08/23/22		1,000		1,002,209
3.45%, 08/11/23(a)		500		525,636
2.20%, 08/16/23		1,000		1,010,233
2.10%, 10/24/24(a)		250		250,326
2.80%, 05/04/26		70		71,992
3.25%, 05/16/27		750		788,503
3.85%, 04/28/28(a)		2,000		2,237,162
3.30%, 08/23/29		1,000		1,046,965
Series G, 3.00%, 02/24/25		105		109,213
Bank of Nova Scotia:
2.45%, 03/22/21		500		504,046
3.13%, 04/20/21		1,750		1,777,642
2.80%, 07/21/21		750		761,282
2.70%, 03/07/22		1,000		1,017,654
2.45%, 09/19/22(a)		2,000		2,030,181
2.00%, 11/15/22		1,000		1,001,614
2.38%, 01/18/23		475		482,167
3.40%, 02/11/24		1,000		1,047,849
4.50%, 12/16/25(a)		250		274,653
2.70%, 08/03/26		1,000		1,017,829
Barclays Bank PLC, 2.65%, 01/11/21		2,000		2,013,083
Barclays PLC:
3.25%, 01/12/21(a)		1,250		1,260,550
3.20%, 08/10/21(a)		750		760,176
3.68%, 01/10/23		1,500		1,538,240
(3 mo. LIBOR US + 1.36%), 4.34%, 05/16/24(c)		2,000		2,108,800
3.65%, 03/16/25		450		468,394
4.38%, 01/12/26		1,000		1,080,300
4.34%, 01/10/28(a)		750		804,973
(3 mo. LIBOR US + 1.90%), 4.97%, 05/16/29(c)		2,250		2,537,124
4.95%, 01/10/47		1,000		1,181,289
BBVA USA:
2.50%, 08/27/24		1,000		991,939
3.88%, 04/10/25		250		262,645
BNP Paribas SA:
3.25%, 03/03/23		250		259,180
5.00%, 01/15/21		100		103,172
4.25%, 10/15/24(a)		250		268,242
BPCE SA:
2.65%, 02/03/21		1,000		1,007,021
4.00%, 04/15/24		250		267,489
Canadian Imperial Bank of Commerce:
(3 mo. LIBOR US + 0.79%), 2.61%, 07/22/23(c)		2,000		2,021,823
3.50%, 09/13/23		2,000		2,098,942
Citibank NA:
2.85%, 02/12/21		2,000		2,019,542
3.40%, 07/23/21		750		766,106
3.65%, 01/23/24		500		529,319
Citizens Bank NA/Providence RI:
2.55%, 05/13/21		1,000		1,007,690
2.65%, 05/26/22		250		253,112
Citizens Financial Group, Inc., 2.85%, 07/27/26		1,500		1,528,642
Comerica, Inc.:
3.70%, 07/31/23		250		262,815
4.00%, 02/01/29		1,000		1,092,563

SCHEDULE OF INVESTMENTS 21

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Banks (continued)
Cooperatieve Rabobank UA:
2.50%, 01/19/21	$	4,000	$	4,023,911
2.75%, 01/10/22		2,000		2,033,780
3.88%, 02/08/22		150		156,223
3.95%, 11/09/22(a)		1,000		1,045,606
2.75%, 01/10/23		2,000		2,039,245
4.63%, 12/01/23(a)		500		541,961
3.38%, 05/21/25		500		530,117
4.38%, 08/04/25		500		542,616
3.75%, 07/21/26(a)		500		520,993
5.25%, 05/24/41(a)		1,025		1,401,170
5.25%, 08/04/45(a)		1,250		1,599,621
Credit Suisse AG, 2.10%, 11/12/21		2,250		2,260,649
Credit Suisse AG, New York:
3.00%, 10/29/21		3,250		3,315,247
3.63%, 09/09/24(a)		1,250		1,329,883
Discover Bank:
3.20%, 08/09/21		1,000		1,017,581
3.35%, 02/06/23(a)		500		515,660
4.20%, 08/08/23		2,000		2,126,229
2.45%, 09/12/24		600		598,927
(5 year USD Swap + 1.73%), 4.68%, 08/09/28(a)(c)		1,000		1,045,000
Fifth Third Bancorp:
3.50%, 03/15/22		100		103,140
4.30%, 01/16/24		250		268,748
8.25%, 03/01/38		425		649,415
Fifth Third Bank:
2.25%, 06/14/21(a)		1,000		1,005,416
3.35%, 07/26/21(a)		1,000		1,022,103
2.88%, 10/01/21		200		203,029
3.95%, 07/28/25		500		543,481
3.85%, 03/15/26		500		532,766
First Republic Bank, 4.63%, 02/13/47(a)		500		570,642
HSBC Holdings PLC:
3.40%, 03/08/21		1,500		1,523,833
5.10%, 04/05/21		500		518,579
2.95%, 05/25/21		500		506,351
2.65%, 01/05/22		1,500		1,516,549
4.88%, 01/14/22(a)		150		158,382
(3 mo. LIBOR US + 1.06%), 3.26%, 03/13/23(c)		1,000		1,022,861
3.60%, 05/25/23		750		782,464
4.25%, 03/14/24(a)		500		530,574
(3 mo. LIBOR US + 0.99%), 3.95%, 05/18/24(a)(c)		380		399,821
4.25%, 08/18/25(a)		500		534,770
(3 mo. LIBOR US + 1.14%), 2.63%, 11/07/25(c)		1,000		1,003,989
4.30%, 03/08/26(a)		1,000		1,089,057
3.90%, 05/25/26		1,000		1,066,723
(3 mo. LIBOR US + 1.35%), 4.29%, 09/12/26(c)		4,000		4,325,702
4.38%, 11/23/26		2,000		2,163,079
(3 mo. LIBOR US + 1.55%), 4.04%, 03/13/28(a)(c)		3,000		3,209,905
(3 mo. LIBOR US + 1.53%), 4.58%, 06/19/29(c)		3,000		3,354,726
(3 mo. LIBOR US + 1.61%), 3.97%, 05/22/30(a)(c)		1,000		1,078,365
6.50%, 05/02/36(a)		200		273,332
6.50%, 09/15/37		750		1,036,903
6.80%, 06/01/38(a)		250		356,228
6.10%, 01/14/42(a)		1,000		1,420,144
5.25%, 03/14/44(a)		1,250		1,581,158
Huntington Bancshares, Inc.:
3.15%, 03/14/21		1,250		1,265,512
2.63%, 08/06/24		775		786,073
4.00%, 05/15/25(a)		2,000		2,161,319

Security	Par (000)		Value
Banks (continued)
ING Groep NV:
4.10%, 10/02/23	$	1,000	$	1,063,302
3.95%, 03/29/27		250		269,588
4.55%, 10/02/28		1,000		1,134,741
4.05%, 04/09/29(a)		1,000		1,098,837
KeyBank NA:
2.50%, 11/22/21		1,000		1,011,307
3.30%, 02/01/22		1,000		1,027,334
2.30%, 09/14/22		350		353,886
3.38%, 03/07/23		250		259,838
3.90%, 04/13/29		1,000		1,074,287
KeyCorp(a):
5.10%, 03/24/21		2,100		2,179,408
2.55%, 10/01/29		500		488,966
KFW:
1.63%, 03/15/21		1,250		1,249,500
2.63%, 04/12/21		2,000		2,024,137
1.50%, 06/15/21		4,500		4,490,008
1.75%, 09/15/21		500		500,900
2.00%, 11/30/21		2,000		2,013,247
2.13%, 03/07/22		2,000		2,019,839
2.13%, 06/15/22		2,250		2,274,772
2.38%, 12/29/22		3,000		3,060,928
2.13%, 01/17/23		200		202,566
2.63%, 02/28/24(a)		1,000		1,035,047
2.50%, 11/20/24		2,000		2,069,348
2.00%, 05/02/25		2,000		2,024,180
2.88%, 04/03/28		5,000		5,348,415
Kreditanstalt fuer Wiederaufbau:
3.13%, 12/15/21		4,000		4,113,405
1.38%, 08/05/24(a)		5,000		4,913,335
1.75%, 09/14/29		500		489,550
Lloyds Bank PLC, 2.25%, 08/14/22		1,000		1,004,960
M&T Bank Corp., 3.55%, 07/26/23		2,000		2,100,034
MUFG Union Bank NA, 2.10%, 12/09/22		1,000		1,002,809
National Australia Bank Ltd.:
3.70%, 11/04/21		500		515,905
2.50%, 05/22/22(a)		1,000		1,011,844
2.88%, 04/12/23		2,000		2,047,587
2.50%, 07/12/26		1,250		1,250,777
Northern Trust Corp., 3.65%, 08/03/28		250		273,115
Oesterreichische Kontrollbank AG, 2.88%, 03/13/23		2,000		2,071,698
PNC Bank NA:
2.15%, 04/29/21		500		501,640
2.45%, 07/28/22(a)		750		760,248
2.95%, 01/30/23		250		255,890
2.95%, 02/23/25(a)		250		258,867
4.05%, 07/26/28		500		548,832
PNC Financial Services Group, Inc.:
3.30%, 03/08/22		75		77,056
3.90%, 04/29/24		2,000		2,128,203
2.20%, 11/01/24		300		301,115
3.45%, 04/23/29		2,000		2,134,779
Regions Financial Corp.:
2.75%, 08/14/22		500		509,041
3.80%, 08/14/23(a)		2,000		2,117,324
Royal Bank of Canada:
2.50%, 01/19/21		250		251,799
3.70%, 10/05/23		2,000		2,114,460
2.55%, 07/16/24(a)		1,000		1,015,389
2.25%, 11/01/24		1,500		1,506,367
4.65%, 01/27/26(a)		700		776,522

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Banks (continued)
Santander Holdings USA, Inc.:
3.40%, 01/18/23	$	2,000	$	2,050,692
3.24%, 10/05/26(b)		2,000		2,022,154
Santander UK Group Holdings PLC:
3.13%, 01/08/21		75		75,641
2.88%, 08/05/21		1,000		1,009,318
(3 mo. LIBOR US + 1.08%), 3.37%, 01/05/24(c)		3,000		3,073,802
Santander UK PLC, 2.88%, 06/18/24(a)		1,500		1,534,209
Skandinaviska Enskilda Banken AB, 2.63%, 03/15/21		1,000		1,006,304
Svenska Handelsbanken AB:
2.45%, 03/30/21		500		503,327
3.35%, 05/24/21(a)		2,000		2,039,472
Synchrony Bank, 3.00%, 06/15/22		500		509,808
Toronto-Dominion Bank:
2.13%, 04/07/21		500		503,004
3.25%, 06/11/21		500		510,660
1.80%, 07/13/21(a)		2,000		2,001,400
1.90%, 12/01/22		730		730,699
3.50%, 07/19/23(a)		500		526,307
2.65%, 06/12/24		500		512,196
(5 year USD Swap + 2.21%), 3.63%, 09/15/31(a)(c)		500		522,948
Truist Bank:
2.45%, 08/01/22		1,000		1,010,875
(3 mo. LIBOR US + 0.59%), 3.50%, 08/02/22(c)		4,000		4,091,122
2.75%, 05/01/23		500		509,037
(3 mo. LIBOR US + 0.74%), 3.69%, 08/02/24(c)		365		383,190
2.15%, 12/06/24		1,000		998,422
3.80%, 10/30/26(a)		250		268,286
(5 year CMT + 1.15%), 2.64%, 09/17/29(c)		1,000		1,000,069
Truist Financial Corp.:
2.90%, 03/03/21		500		505,229
2.75%, 04/01/22(a)		1,000		1,017,721
3.75%, 12/06/23(a)		2,000		2,121,657
2.50%, 08/01/24		2,000		2,026,336
2.85%, 10/26/24		500		516,606
US Bancorp, 2.95%, 07/15/22		2,000		2,046,697
US Bancorp.:
4.13%, 05/24/21(a)		50		51,472
2.40%, 07/30/24		1,000		1,013,920
3.90%, 04/26/28(a)		2,000		2,244,433
Series V, 2.63%, 01/24/22(a)		2,000		2,031,720
Series V, 2.38%, 07/22/26		500		501,561
US Bank NA:
3.40%, 07/24/23		3,000		3,134,501
2.80%, 01/27/25		500		517,059
Wells Fargo & Co.:
3.00%, 01/22/21		250		252,918
2.50%, 03/04/21		2,740		2,759,689
4.60%, 04/01/21		1,000		1,032,453
2.10%, 07/26/21		1,000		1,001,469
3.50%, 03/08/22		5,000		5,163,567
2.63%, 07/22/22		3,750		3,806,040
3.07%, 01/24/23		2,500		2,551,590
4.13%, 08/15/23(a)		1,750		1,858,220
4.48%, 01/16/24		250		270,006
3.30%, 09/09/24(a)		750		786,019
3.00%, 02/19/25		350		361,173
3.55%, 09/29/25		1,000		1,058,912
(3 mo. LIBOR US + 0.83%), 2.41%, 10/30/25(c)		1,000		1,000,942
3.00%, 04/22/26		1,750		1,800,200
4.10%, 06/03/26(a)		2,020		2,178,384

Security	Par (000)		Value
Banks (continued)
3.00%, 10/23/26	$	1,750	$	1,793,581
(3 mo. LIBOR US + 1.17%), 3.20%, 06/17/27(c)		1,335		1,385,281
4.30%, 07/22/27		1,500		1,643,833
(3 mo. LIBOR US + 1.31%), 3.58%, 05/22/28(c)		1,500		1,594,600
4.15%, 01/24/29		2,000		2,227,928
(3 mo. LIBOR US + 1.17%), 2.88%, 10/30/30(c)		1,000		1,006,951
5.38%, 11/02/43(a)		900		1,155,889
5.61%, 01/15/44		656		864,507
4.65%, 11/04/44		3,345		3,934,344
3.90%, 05/01/45		150		170,139
4.90%, 11/17/45		500		611,641
4.40%, 06/14/46		600		684,370
4.75%, 12/07/46		1,600		1,921,433
Series M, 3.45%, 02/13/23		450		466,037
Wells Fargo Bank N.A., 3.55%, 08/14/23		500		524,036
Wells Fargo Bank NA:
2.60%, 01/15/21		2,000		2,014,025
(3 mo. LIBOR US + 0.65%), 2.08%, 09/09/22(c)		1,000		1,001,550
6.60%, 01/15/38		500		723,718
Westpac Banking Corp.:
2.65%, 01/25/21		4,000		4,027,089
2.10%, 05/13/21		500		501,466
2.75%, 01/11/23		3,000		3,056,816
2.35%, 02/19/25		500		501,240
2.85%, 05/13/26		500		512,243
3.40%, 01/25/28		500		532,948
(5 year USD ICE Swap + 2.24%), 4.32%, 11/23/31(c)		750		794,215
4.42%, 07/24/39		1,000		1,100,087
Zions Bancorp NA, 3.25%, 10/29/29		1,000		982,014
3.50%, 08/27/21		250		255,856
				305,864,538
Beverages — 0.7%
Anheuser-Busch Cos. LLC/Anheuser-Busch InBev Worldwide, Inc.:
3.65%, 02/01/26		2,250		2,399,766
4.70%, 02/01/36(a)		2,500		2,896,886
4.90%, 02/01/46		5,620		6,666,009
Anheuser-Busch InBev Finance, Inc.:
3.30%, 02/01/23		4,036		4,181,501
3.65%, 02/01/26		500		530,939
4.63%, 02/01/44		650		737,262
4.90%, 02/01/46		500		590,609
Anheuser-Busch InBev Worldwide, Inc.:
4.15%, 01/23/25		2,000		2,179,738
4.00%, 04/13/28		1,000		1,100,553
4.75%, 01/23/29		500		579,585
4.38%, 04/15/38		1,000		1,123,382
8.20%, 01/15/39(a)		150		237,238
5.45%, 01/23/39		1,000		1,258,432
4.95%, 01/15/42		500		591,863
3.75%, 07/15/42(a)		300		310,204
4.60%, 04/15/48		1,000		1,144,404
4.44%, 10/06/48		632		708,860
5.55%, 01/23/49(a)		3,000		3,897,949
4.75%, 04/15/58(a)		500		584,796
5.80%, 01/23/59		1,000		1,365,738
Coca-Cola Co.:
3.30%, 09/01/21(a)		2,000		2,049,568
2.20%, 05/25/22(a)		250		252,602
1.75%, 09/06/24		1,000		993,152
2.88%, 10/27/25(a)		125		130,345
2.55%, 06/01/26(a)		750		766,717

SCHEDULE OF INVESTMENTS 23

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Beverages (continued)
2.90%, 05/25/27	$	250	$	261,405
2.13%, 09/06/29		1,000		974,864
Coca-Cola Femsa SAB de CV, 3.88%, 11/26/23(a)		500		527,344
Constellation Brands, Inc.:
2.65%, 11/07/22		4,000		4,056,300
3.70%, 12/06/26(a)		750		796,443
3.50%, 05/09/27(a)		1,000		1,044,814
3.15%, 08/01/29		2,000		2,022,953
Diageo Capital PLC:
2.63%, 04/29/23(a)		250		255,335
3.50%, 09/18/23(a)		2,000		2,107,023
3.88%, 05/18/28		1,000		1,096,716
2.38%, 10/24/29(a)		830		818,939
3.88%, 04/29/43		125		138,085
Diageo Investment Corp.:
2.88%, 05/11/22		100		102,021
4.25%, 05/11/42(a)		250		288,165
Keurig Dr. Pepper, Inc.:
3.55%, 05/25/21		1,750		1,787,379
2.70%, 11/15/22		100		100,965
4.06%, 05/25/23		500		527,351
4.42%, 05/25/25		250		273,043
4.60%, 05/25/28		750		842,208
4.99%, 05/25/38		250		295,214
4.42%, 12/15/46		500		538,936
5.09%, 05/25/48		750		903,636
Molson Coors Brewing Co.:
2.10%, 07/15/21		750		750,657
3.50%, 05/01/22(a)		75		77,107
3.00%, 07/15/26(a)		2,345		2,374,194
5.00%, 05/01/42		750		820,091
4.20%, 07/15/46		500		499,075
PepsiCo, Inc.:
3.00%, 08/25/21		750		764,946
2.75%, 03/05/22		250		255,227
3.10%, 07/17/22		500		515,932
2.75%, 03/01/23		300		308,349
3.60%, 03/01/24(a)		250		266,202
2.75%, 04/30/25		1,000		1,036,177
3.50%, 07/17/25		250		268,517
2.85%, 02/24/26		500		519,368
2.38%, 10/06/26		1,000		1,015,187
3.00%, 10/15/27		1,000		1,060,091
2.63%, 07/29/29(a)		1,000		1,020,674
3.60%, 08/13/42		100		107,529
4.60%, 07/17/45(a)		500		620,309
4.45%, 04/14/46(a)		1,000		1,228,538
3.45%, 10/06/46		2,250		2,388,583
2.88%, 10/15/49(a)		500		483,615
				73,417,605
Biotechnology — 0.3%
Amgen, Inc.:
4.10%, 06/15/21		250		256,848
1.85%, 08/19/21		250		249,463
3.88%, 11/15/21		1,000		1,031,572
2.70%, 05/01/22		500		506,756
2.25%, 08/19/23		250		252,349
3.63%, 05/22/24		250		264,173
3.13%, 05/01/25(a)		750		782,519
2.60%, 08/19/26(a)		715		724,388
3.20%, 11/02/27(a)		2,000		2,107,844
4.95%, 10/01/41		2,000		2,382,463
5.65%, 06/15/42(a)		750		951,582

Security	Par (000)		Value
Biotechnology (continued)
4.40%, 05/01/45	$	925	$	1,036,508
4.56%, 06/15/48		500		581,229
4.66%, 06/15/51(a)		904		1,065,123
Baxalta, Inc.:
4.00%, 06/23/25		1,398		1,506,506
5.25%, 06/23/45		105		135,614
Biogen, Inc.:
4.05%, 09/15/25		595		647,265
5.20%, 09/15/45		750		905,812
Gilead Sciences, Inc.:
1.95%, 03/01/22		1,000		1,001,420
2.50%, 09/01/23		500		507,616
3.70%, 04/01/24		1,750		1,855,925
3.50%, 02/01/25		170		180,451
3.65%, 03/01/26(a)		1,325		1,427,018
2.95%, 03/01/27(a)		500		519,466
4.60%, 09/01/35		1,350		1,612,067
5.65%, 12/01/41(a)		50		65,713
4.80%, 04/01/44		500		600,891
4.50%, 02/01/45		1,150		1,336,876
4.75%, 03/01/46(a)		1,000		1,202,535
4.15%, 03/01/47(a)		1,500		1,671,083
				27,369,075
Building Materials — 0.0%
Martin Marietta Materials, Inc., 4.25%, 12/15/47		250		259,952
Building Products — 0.1%
Allegion PLC, 3.50%, 10/01/29		500		508,983
Fortune Brands Home & Security, Inc., 3.25%, 09/15/29(a)		500		505,708
Johnson Controls International PLC:
3.63%, 07/02/24(d)		75		78,300
4.63%, 07/02/44		750		824,437
5.13%, 09/14/45		24		28,041
4.50%, 02/15/47(a)		250		270,421
4.95%, 07/02/64(a)(d)		179		189,398
Masco Corp., 4.38%, 04/01/26(a)		1,000		1,080,705
Owens Corning:
4.20%, 12/01/24		250		263,820
4.40%, 01/30/48		1,000		967,374
				4,717,187
Capital Markets — 0.9%
Ameriprise Financial, Inc.:
4.00%, 10/15/23		150		160,785
2.88%, 09/15/26(a)		500		511,117
Brookfield Asset Management, Inc., 4.00%, 01/15/25		250		268,927
Brookfield Finance, Inc.:
4.00%, 04/01/24		150		160,887
3.90%, 01/25/28(a)		1,000		1,072,573
4.70%, 09/20/47		500		575,105
Charles Schwab Corp.:
3.00%, 03/10/25		80		83,067
3.85%, 05/21/25(a)		1,000		1,083,676
3.20%, 01/25/28(a)		1,000		1,050,777
3.25%, 05/22/29(a)		200		211,767
CME Group, Inc.:
3.00%, 09/15/22		1,000		1,029,479
3.00%, 03/15/25		250		259,749
3.75%, 06/15/28		1,000		1,104,898
5.30%, 09/15/43(a)		100		133,997
Franklin Resources, Inc., 2.80%, 09/15/22		150		153,290

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Capital Markets (continued)
FS KKR Capital Corp.:
4.63%, 07/15/24(a)	$	500	$	519,602
4.13%, 02/01/25		100		101,412
Goldman Sachs Group, Inc.:
2.88%, 02/25/21		1,000		1,009,957
2.63%, 04/25/21		500		504,364
5.25%, 07/27/21		500		524,710
2.35%, 11/15/21		1,500		1,505,960
5.75%, 01/24/22		2,350		2,522,761
3.00%, 04/26/22		3,000		3,037,890
(3 mo. LIBOR US + 0.82%), 2.88%, 10/31/22(c)		1,000		1,014,189
3.63%, 01/22/23(a)		150		156,229
(3 mo. LIBOR US + 0.99%), 2.91%, 07/24/23(c)		2,000		2,036,104
4.00%, 03/03/24(a)		3,425		3,649,805
3.85%, 07/08/24(a)		500		528,848
3.50%, 01/23/25		750		787,359
3.75%, 05/22/25		2,250		2,388,495
(3 mo. LIBOR US + 1.20%), 3.27%, 09/29/25(c)		1,000		1,035,304
4.25%, 10/21/25		1,050		1,140,547
3.75%, 02/25/26(a)		380		402,236
5.95%, 01/15/27		250		298,776
3.85%, 01/26/27		2,000		2,129,096
(3 mo. LIBOR US + 1.51%), 3.69%, 06/05/28(a)(c)		500		531,993
(3 mo. LIBOR US + 1.16%), 3.81%, 04/23/29(c)		1,000		1,072,878
(3 mo. LIBOR US + 1.30%), 4.22%, 05/01/29(a)(c)		1,000		1,102,579
6.75%, 10/01/37		1,650		2,292,063
(3 mo. LIBOR US + 1.37%), 4.02%, 10/31/38(a)(c)		2,000		2,173,561
(3 mo. LIBOR US + 1.43%), 4.41%, 04/23/39(c)		2,400		2,734,902
4.80%, 07/08/44		1,250		1,514,085
5.15%, 05/22/45		1,500		1,843,852
4.75%, 10/21/45		1,750		2,136,428
Invesco Finance PLC, 4.00%, 01/30/24(a)		250		265,757
Jefferies Group LLC, 5.13%, 01/20/23		650		701,986
Jefferies Group LLC/Jefferies Group Capital Finance, Inc.:
4.85%, 01/15/27(a)		1,000		1,104,526
4.15%, 01/23/30		1,000		1,060,480
Landwirtschaftliche Rentenbank, Series 36, 2.00%, 12/06/21		2,000		2,013,011
Lazard Group LLC, 4.38%, 03/11/29(a)		1,000		1,089,936
Legg Mason, Inc., 5.63%, 01/15/44		625		709,835
Morgan Stanley:
5.75%, 01/25/21		750		778,928
2.50%, 04/21/21		500		503,791
5.50%, 07/28/21		1,600		1,685,486
2.63%, 11/17/21		2,750		2,782,966
2.75%, 05/19/22(a)		2,000		2,036,934
4.88%, 11/01/22		500		535,756
3.13%, 01/23/23		3,500		3,598,300
3.75%, 02/25/23(a)		500		523,605
4.10%, 05/22/23		250		263,990
(3 mo. LIBOR US + 0.85%), 3.74%, 04/24/24(c)		4,000		4,179,588
3.70%, 10/23/24		500		531,152
(Secured Overnight Financing Rate + 1.15%), 2.72%, 07/22/25(a)(c)		605		612,649
4.00%, 07/23/25		505		546,442
5.00%, 11/24/25(a)		1,250		1,408,007
3.88%, 01/27/26		500		537,047
3.13%, 07/27/26		500		516,271
4.35%, 09/08/26(a)		1,500		1,640,826
3.63%, 01/20/27		2,000		2,129,628
3.95%, 04/23/27		250		268,227
(3 mo. LIBOR US + 1.34%), 3.59%, 07/22/28(c)		2,250		2,392,455

Security	Par (000)		Value
Capital Markets (continued)
(3 mo. LIBOR US + 1.14%), 3.77%, 01/24/29(c)	$	3,000	$	3,229,358
(3 mo. LIBOR US + 1.63%), 4.43%, 01/23/30(c)		750		848,307
7.25%, 04/01/32		50		71,550
(3 mo. LIBOR US + 1.46%), 3.97%, 07/22/38(c)		1,000		1,110,939
(3 mo. LIBOR US + 1.43%), 4.46%, 04/22/39(a)(c)		3,000		3,536,215
6.38%, 07/24/42		50		73,713
4.30%, 01/27/45		500		588,158
4.38%, 01/22/47		1,000		1,199,281
Series F, 3.88%, 04/29/24		250		265,770
Nasdaq, Inc., 4.25%, 06/01/24		250		269,154
Owl Rock Capital Corp., 4.00%, 03/30/25		345		346,369
Raymond James Financial, Inc., 4.95%, 07/15/46		500		584,620
State Street Corp.:
3.10%, 05/15/23		250		257,981
3.30%, 12/16/24		405		427,258
(Secured Overnight Financing Rate + 0.94%), 2.35%, 11/01/25(c)		450		451,983
2.65%, 05/19/26(a)		1,000		1,017,920
(Secured Overnight Financing Rate + 1.49%), 3.03%, 11/01/34(c)		200		200,781
TD Ameritrade Holding Corp.:
2.95%, 04/01/22		250		255,575
3.63%, 04/01/25(a)		1,000		1,064,203
2.75%, 10/01/29		1,000		1,000,653
TPG Specialty Lending, Inc., 3.88%, 11/01/24		500		503,683
				100,277,129
Chemicals — 0.4%
Albemarle Corp., 4.15%, 12/01/24(a)		250		267,960
Cabot Corp., 4.00%, 07/01/29		1,500		1,573,373
Dow Chemical Co.:
3.00%, 11/15/22(a)		250		255,650
3.50%, 10/01/24		1,000		1,050,255
4.80%, 11/30/28		300		343,194
4.25%, 10/01/34(a)		1,600		1,750,731
9.40%, 05/15/39(a)		250		409,097
5.25%, 11/15/41		100		116,574
4.38%, 11/15/42(a)		250		267,041
5.55%, 11/30/48		1,000		1,249,987
DuPont de Nemours, Inc.:
4.21%, 11/15/23		2,000		2,139,897
4.73%, 11/15/28(a)		1,500		1,703,159
5.32%, 11/15/38(a)		750		895,253
5.42%, 11/15/48		1,000		1,233,880
Eastman Chemical Co.:
3.60%, 08/15/22		200		207,026
3.80%, 03/15/25(a)		1,050		1,107,731
4.50%, 12/01/28(a)		1,000		1,107,579
4.80%, 09/01/42		250		271,723
FMC Corp.:
3.20%, 10/01/26		155		158,335
3.45%, 10/01/29		115		118,908
4.50%, 10/01/49		165		180,047
International Flavors & Fragrances, Inc.(a):
4.45%, 09/26/28		500		546,844
5.00%, 09/26/48		500		567,695
LYB International Finance BV:
4.00%, 07/15/23		450		476,015
5.25%, 07/15/43		75		88,593
4.88%, 03/15/44(a)		350		394,379
LYB International Finance II BV, 3.50%, 03/02/27(a)		1,000		1,048,304
LYB International Finance III LLC, 4.20%, 10/15/49		330		344,434
LyondellBasell Industries NV, 4.63%, 02/26/55		600		631,358

SCHEDULE OF INVESTMENTS 25

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Chemicals (continued)
Methanex Corp.:
4.25%, 12/01/24	$	250	$	257,822
5.25%, 12/15/29		250		258,343
Mosaic Co.:
3.75%, 11/15/21		50		51,426
4.25%, 11/15/23(a)		1,000		1,066,825
4.05%, 11/15/27		1,000		1,038,490
5.45%, 11/15/33		250		283,797
Nutrien Ltd.:
3.15%, 10/01/22		1,050		1,072,857
3.50%, 06/01/23		250		258,110
3.63%, 03/15/24		250		261,143
3.38%, 03/15/25		1,395		1,445,610
3.00%, 04/01/25		250		255,141
4.00%, 12/15/26(a)		250		266,240
4.90%, 06/01/43		500		563,445
5.00%, 04/01/49		750		894,484
PPG Industries, Inc.:
2.40%, 08/15/24		1,000		1,010,013
2.80%, 08/15/29		1,000		1,007,945
Praxair, Inc.:
2.70%, 02/21/23(a)		1,000		1,021,376
2.65%, 02/05/25		165		168,975
3.20%, 01/30/26		250		263,540
Rohm & Haas Co., 7.85%, 07/15/29		250		334,289
RPM International, Inc., 5.25%, 06/01/45		250		280,133
SASOL Financing USA LLC:
5.88%, 03/27/24(a)		500		541,719
6.50%, 09/27/28		750		832,969
Sherwin-Williams Co.:
3.95%, 01/15/26(a)		500		535,134
3.45%, 06/01/27		250		264,535
2.95%, 08/15/29		620		626,218
4.50%, 06/01/47(a)		1,500		1,705,023
3.80%, 08/15/49		880		897,155
Westlake Chemical Corp.:
3.60%, 08/15/26		500		518,354
5.00%, 08/15/46		750		795,286
				39,281,419
Commercial Services & Supplies — 0.1%
American University, Series 2019, 3.67%, 04/01/49		135		144,795
California Institute of Technology, 3.65%, 09/01/19		263		255,094
Ecolab, Inc.:
4.35%, 12/08/21		122		127,757
2.38%, 08/10/22		500		505,123
3.25%, 01/14/23		250		257,992
3.25%, 12/01/27(a)		1,000		1,057,137
3.70%, 11/01/46		250		259,185
George Washington University:
4.87%, 09/15/45		100		125,449
Series 2014, 4.30%, 09/15/44		250		290,647
Series 2018, 4.13%, 09/15/48		164		189,320
Georgetown University:
Series A, 5.22%, 10/01/18		62		79,339
Series B, 4.32%, 04/01/49		40		47,847
Leland Stanford Junior University, 3.65%, 05/01/48(a)		250		278,998
Massachusetts Institute of Technology:
4.68%, 07/01/14		300		386,891
Series F, 2.99%, 07/01/50		289		287,078
Northwestern University:
3.87%, 12/01/48		100		112,310
Series 2017, 3.66%, 12/01/57		58		64,115

Security	Par (000)		Value
Commercial Services & Supplies (continued)
President and Fellows of Harvard College:
3.15%, 07/15/46	$	175	$	178,814
3.30%, 07/15/56(a)		200		206,946
Republic Services, Inc.:
5.25%, 11/15/21		50		53,040
3.55%, 06/01/22(a)		250		258,287
4.75%, 05/15/23(a)		250		269,231
2.50%, 08/15/24		205		207,348
3.20%, 03/15/25		250		260,130
2.90%, 07/01/26		85		87,087
3.95%, 05/15/28(a)		1,750		1,928,491
Trustees of Boston University, Series CC, 4.06%, 10/01/48		35		40,185
University of Notre Dame du Lac, Series 2017, 3.39%, 02/15/48		110		117,174
University of Southern California, 3.03%, 10/01/39(a)		200		201,069
Waste Management, Inc.:
4.60%, 03/01/21(a)		100		102,465
2.90%, 09/15/22		200		204,638
2.40%, 05/15/23		500		505,147
3.15%, 11/15/27		1,000		1,043,519
3.45%, 06/15/29		1,500		1,606,434
3.90%, 03/01/35(a)		315		347,253
4.15%, 07/15/49(a)		500		572,119
William Marsh Rice University, 3.77%, 05/15/55		300		329,374
				12,987,828
Communications Equipment — 0.1%
Cisco Systems, Inc.:
2.20%, 02/28/21		1,000		1,005,853
2.90%, 03/04/21(a)		125		126,667
1.85%, 09/20/21		4,000		4,002,739
2.60%, 02/28/23(a)		500		511,241
2.95%, 02/28/26		500		521,550
5.90%, 02/15/39		500		700,736
5.50%, 01/15/40		850		1,161,335
Juniper Networks, Inc.(a):
4.35%, 06/15/25		250		269,022
3.75%, 08/15/29		1,000		1,040,165
5.95%, 03/15/41		500		570,259
Motorola Solutions, Inc.:
3.75%, 05/15/22		85		87,899
3.50%, 03/01/23		250		258,226
4.60%, 02/23/28		500		542,295
4.60%, 05/23/29(a)		965		1,053,436
				11,851,423
Construction & Engineering — 0.0%
ABB Finance USA, Inc.:
2.88%, 05/08/22		100		102,121
3.80%, 04/03/28		1,000		1,092,028
Fluor Corp., 3.50%, 12/15/24(a)		1,250		1,276,537
				2,470,686
Construction Materials — 0.0%
Vulcan Materials Co., 3.90%, 04/01/27(a)		1,000		1,056,959
WW Grainger, Inc., 4.60%, 06/15/45		1,250		1,494,618
				2,551,577
Consumer Discretionary — 0.0%
Royal Caribbean Cruises Ltd.:
5.25%, 11/15/22		1,000		1,082,873
3.70%, 03/15/28(a)		225		231,547
				1,314,420

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Consumer Finance — 0.5%
Ally Financial, Inc.:
4.25%, 04/15/21(a)	$	2,000	$	2,045,000
4.13%, 02/13/22		500		516,250
4.63%, 05/19/22(a)		500		523,750
3.88%, 05/21/24		1,500		1,571,250
5.13%, 09/30/24		300		330,837
4.63%, 03/30/25		2,500		2,706,250
American Express Co.:
3.38%, 05/17/21		3,000		3,057,367
2.65%, 12/02/22		1,000		1,019,270
3.40%, 02/27/23(a)		500		519,180
3.70%, 08/03/23		2,000		2,102,792
3.40%, 02/22/24		3,000		3,138,326
2.50%, 07/30/24		655		662,664
3.00%, 10/30/24(a)		1,000		1,033,922
3.63%, 12/05/24		300		317,184
4.05%, 12/03/42(a)		67		78,942
Capital One Bank USA NA, 3.38%, 02/15/23(a)		350		361,619
Capital One Financial Corp.:
4.75%, 07/15/21		1,000		1,041,447
3.20%, 01/30/23		4,000		4,112,755
3.50%, 06/15/23		110		114,319
3.75%, 04/24/24		250		263,305
3.20%, 02/05/25		250		258,993
4.20%, 10/29/25		340		367,025
3.75%, 07/28/26		230		242,344
3.75%, 03/09/27(a)		500		533,354
3.80%, 01/31/28(a)		1,000		1,075,424
Capital One NA:
2.25%, 09/13/21		1,000		1,004,517
2.15%, 09/06/22(a)		455		455,772
Caterpillar Financial Services Corp.:
1.70%, 08/09/21		1,000		998,563
2.95%, 02/26/22		1,000		1,022,796
1.90%, 09/06/22		1,000		1,002,019
2.63%, 03/01/23		2,000		2,037,896
3.45%, 05/15/23		400		419,035
3.65%, 12/07/23		1,000		1,061,361
3.30%, 06/09/24(a)		250		262,881
2.15%, 11/08/24		200		200,815
Discover Financial Services:
3.95%, 11/06/24		350		371,755
3.75%, 03/04/25		75		79,449
Mastercard, Inc.:
3.38%, 04/01/24(a)		250		265,302
2.00%, 03/03/25		1,200		1,197,030
3.50%, 02/26/28(a)		1,000		1,078,730
2.95%, 06/01/29		2,500		2,609,010
3.65%, 06/01/49		500		555,440
Synchrony Financial:
3.75%, 08/15/21		1,500		1,534,135
2.85%, 07/25/22(a)		175		177,162
4.50%, 07/23/25		190		205,012
3.95%, 12/01/27(a)		1,000		1,051,071
5.15%, 03/19/29(a)		500		568,945
Visa, Inc.:
2.15%, 09/15/22(a)		2,000		2,022,765
2.80%, 12/14/22		750		771,802
3.15%, 12/14/25		1,945		2,056,379
2.75%, 09/15/27(a)		2,150		2,249,963
4.15%, 12/14/35		500		589,798
4.30%, 12/14/45		1,750		2,151,284
3.65%, 09/15/47(a)		195		218,481
				56,212,737

Security	Par (000)		Value
Containers & Packaging — 0.0%
Packaging Corp. of America:
4.50%, 11/01/23(a)	$	250	$	268,623
3.00%, 12/15/29		200		201,026
4.05%, 12/15/49		150		155,942
WRKCo, Inc.:
4.65%, 03/15/26(a)		1,170		1,287,809
3.38%, 09/15/27(a)		500		511,997
4.00%, 03/15/28		1,000		1,075,327
				3,500,724
Diversified Financial Services — 2.9%
AerCap Ireland Capital DAC/AerCap Global Aviation Trust:
3.95%, 02/01/22		1,250		1,291,555
3.30%, 01/23/23(a)		500		512,551
2.88%, 08/14/24		1,000		1,008,998
4.45%, 04/03/26		1,000		1,073,570
3.65%, 07/21/27		1,000		1,030,449
3.88%, 01/23/28		500		519,316
Air Lease Corp.:
3.88%, 04/01/21		175		178,589
2.25%, 01/15/23(a)		1,095		1,096,029
4.25%, 09/15/24		250		267,844
3.25%, 03/01/25(a)		2,000		2,059,329
3.63%, 12/01/27		200		207,097
3.25%, 10/01/29		500		497,404
Aircastle Ltd.:
5.00%, 04/01/23		100		106,958
4.13%, 05/01/24(a)		1,000		1,050,713
4.25%, 06/15/26		500		529,145
American Express Credit Corp.:
2.25%, 05/05/21		1,000		1,004,819
2.70%, 03/03/22		1,000		1,016,787
3.30%, 05/03/27		500		531,161
Banco Santander SA:
3.50%, 04/11/22		1,600		1,643,724
3.13%, 02/23/23		1,000		1,020,757
2.71%, 06/27/24		1,000		1,014,241
5.18%, 11/19/25		200		224,097
4.38%, 04/12/28(a)		1,000		1,094,843
3.31%, 06/27/29		600		618,383
Bank of America Corp.:
2.63%, 04/19/21		1,500		1,513,743
2.50%, 10/21/22		1,000		1,009,734
3.30%, 01/11/23		1,000		1,033,882
(3 mo. LIBOR US + 1.02%), 2.88%, 04/24/23(a)(c)		1,000		1,016,825
(3 mo. LIBOR US + 0.93%), 2.82%, 07/21/23(c)		500		507,997
4.10%, 07/24/23		4,000		4,266,773
(3 mo. LIBOR US + 0.79%), 3.00%, 12/20/23(c)		5,144		5,264,086
(3 mo. LIBOR US + 0.78%), 3.55%, 03/05/24(c)		1,000		1,037,855
4.00%, 04/01/24(a)		500		535,542
(3 mo. LIBOR US + 0.94%), 3.86%, 07/23/24(c)		1,500		1,578,573
4.20%, 08/26/24		750		805,361
4.00%, 01/22/25		750		800,023
3.88%, 08/01/25(a)		2,250		2,417,765
(3 mo. LIBOR US + 1.09%), 3.09%, 10/01/25(c)		1,000		1,032,094
(3 mo. LIBOR US + 0.87%), 2.46%, 10/22/25(c)		385		387,576
(3 mo. LIBOR US + 0.81%), 3.37%, 01/23/26(a)(c)		2,000		2,091,997
4.45%, 03/03/26		1,340		1,471,735
3.50%, 04/19/26		645		685,991
4.25%, 10/22/26		1,290		1,407,144
3.25%, 10/21/27		1,375		1,433,379
(3 mo. LIBOR US + 1.58%), 3.82%, 01/20/28(c)		2,000		2,147,407
(3 mo. LIBOR US + 1.51%), 3.71%, 04/24/28(c)		1,000		1,069,255

SCHEDULE OF INVESTMENTS 27

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Diversified Financial Services (continued)
(3 mo. LIBOR US + 1.37%), 3.59%, 07/21/28(c)	$	500	$	530,039
(3 mo. LIBOR US + 1.04%), 3.42%, 12/20/28(c)		3,044		3,196,638
(3 mo. LIBOR US + 1.07%), 3.97%, 03/05/29(c)		1,000		1,089,772
(3 mo. LIBOR US + 1.31%), 4.27%, 07/23/29(c)		1,450		1,611,697
(3 mo. LIBOR US + 1.21%), 3.97%, 02/07/30(c)		2,650		2,909,350
(3 mo. LIBOR US + 1.18%), 3.19%, 07/23/30(c)		965		998,373
(3 mo. LIBOR US + 0.01%), 2.88%, 10/22/30(a)(c)		1,000		1,008,785
6.11%, 01/29/37		350		473,105
(3 mo. LIBOR US + 1.81%), 4.24%, 04/24/38(a)(c)		1,500		1,729,379
7.75%, 05/14/38		200		315,281
5.88%, 02/07/42		1,100		1,562,925
5.00%, 01/21/44		1,250		1,630,381
(3 mo. LIBOR US + 1.99%), 4.44%, 01/20/48(a)(c)		1,150		1,402,808
(3 mo. LIBOR US + 1.52%), 4.33%, 03/15/50(c)		3,000		3,616,660
Series L, 3.95%, 04/21/25(a)		2,155		2,301,447
Series L, 4.18%, 11/25/27(a)		1,000		1,084,447
Citigroup, Inc.:
2.70%, 03/30/21		4,750		4,794,604
2.35%, 08/02/21		4,000		4,024,686
2.90%, 12/08/21		750		762,326
2.75%, 04/25/22		1,500		1,524,034
4.05%, 07/30/22		250		261,290
2.70%, 10/27/22		500		508,324
(Secured Overnight Financing Rate + 0.87%), 2.31%, 11/04/22(c)		700		702,179
(3 mo. LIBOR US + 0.72%), 3.14%, 01/24/23(c)		500		509,797
3.50%, 05/15/23(a)		500		520,417
(3 mo. LIBOR US + 0.95%), 2.88%, 07/24/23(c)		500		508,460
3.88%, 03/26/25		500		528,966
(3 mo. LIBOR US + 0.90%), 3.35%, 04/24/25(c)		4,000		4,163,220
3.30%, 04/27/25		155		162,790
4.40%, 06/10/25		500		543,546
3.70%, 01/12/26		1,000		1,066,632
4.60%, 03/09/26		250		275,288
3.40%, 05/01/26(a)		500		525,336
3.20%, 10/21/26		500		518,794
4.30%, 11/20/26(a)		150		163,343
4.45%, 09/29/27(a)		3,000		3,305,344
(3 mo. LIBOR US + 1.56%), 3.89%, 01/10/28(a)(c)		1,000		1,077,712
(3 mo. LIBOR US + 1.39%), 3.67%, 07/24/28(c)		1,000		1,066,142
4.13%, 07/25/28(a)		750		818,452
(3 mo. LIBOR US + 1.15%), 3.52%, 10/27/28(c)		3,000		3,158,691
(Secured Overnight Financing Rate + 1.42%), 2.98%, 11/05/30(c)		1,000		1,015,556
6.63%, 06/15/32		100		134,674
6.13%, 08/25/36		184		239,661
8.13%, 07/15/39		575		959,938
5.88%, 01/30/42(a)		3,000		4,223,276
6.68%, 09/13/43		250		365,028
5.30%, 05/06/44(a)		500		637,911
4.65%, 07/30/45		250		309,762
4.75%, 05/18/46		500		598,065
(3 mo. LIBOR US + 1.84%), 4.28%, 04/24/48(a)(c)		1,000		1,189,096
4.65%, 07/23/48(a)		1,500		1,876,245
Credit Suisse Group Funding Guernsey Ltd.:
3.45%, 04/16/21		2,000		2,034,259
3.80%, 09/15/22		500		520,573
3.80%, 06/09/23		1,000		1,047,022
3.75%, 03/26/25(a)		500		529,276
4.55%, 04/17/26		250		277,558
4.88%, 05/15/45		1,500		1,893,882
Deutsche Bank AG:
3.13%, 01/13/21		200		200,761

Security	Par (000)		Value
Diversified Financial Services (continued)
(Secured Overnight Financing Rate + 2.58%), 3.96%, 11/26/25(c)	$	800	$	817,436
4.10%, 01/13/26		350		355,992
Deutsche Bank AG, London, 3.70%, 05/30/24		215		218,818
Deutsche Bank AG, New York:
3.13%, 01/13/21		300		301,142
3.15%, 01/22/21		500		502,274
4.25%, 10/14/21(a)		2,000		2,057,044
3.95%, 02/27/23		2,000		2,051,124
E*TRADE Financial Corp., 4.50%, 06/20/28		1,000		1,087,860
Ford Motor Credit Co. LLC:
3.20%, 01/15/21(a)		500		502,797
5.75%, 02/01/21		250		258,072
3.34%, 03/18/21		500		503,760
3.81%, 10/12/21(a)		2,000		2,037,074
3.35%, 11/01/22		500		505,087
4.14%, 02/15/23		1,000		1,028,871
3.10%, 05/04/23(a)		500		499,626
4.38%, 08/06/23		220		228,775
5.58%, 03/18/24		1,000		1,082,540
3.66%, 09/08/24(a)		1,000		1,005,491
4.06%, 11/01/24		500		510,293
4.69%, 06/09/25		500		519,821
4.13%, 08/04/25		500		507,033
4.39%, 01/08/26		250		254,097
4.54%, 08/01/26		500		511,656
3.82%, 11/02/27		2,250		2,181,939
GE Capital International Funding Co.:
3.37%, 11/15/25(a)		1,427		1,486,918
4.42%, 11/15/35		5,685		6,081,438
General Motors Financial Co., Inc.:
4.20%, 03/01/21(a)		750		766,216
3.45%, 04/10/22		400		409,094
3.55%, 07/08/22(a)		1,000		1,029,429
3.25%, 01/05/23		3,000		3,066,319
5.10%, 01/17/24		1,000		1,085,632
3.95%, 04/13/24(a)		1,000		1,045,455
4.00%, 01/15/25(a)		250		262,807
4.30%, 07/13/25		1,000		1,068,945
5.25%, 03/01/26		405		449,153
5.65%, 01/17/29		250		282,696
Genpact Luxembourg Sarl, 3.38%, 12/01/24(a)		1,000		1,004,638
Intercontinental Exchange, Inc.:
2.35%, 09/15/22		2,000		2,021,226
3.75%, 12/01/25(a)		1,115		1,200,762
3.75%, 09/21/28		1,135		1,239,348
4.25%, 09/21/48		500		591,799
Jefferies Financial Group, Inc., 5.50%, 10/18/23		150		163,133
John Deere Capital Corp.:
2.35%, 01/08/21		4,000		4,021,593
2.80%, 03/04/21		250		253,098
3.90%, 07/12/21		50		51,671
2.65%, 01/06/22		140		142,348
2.75%, 03/15/22(a)		500		509,647
2.95%, 04/01/22(a)		500		511,970
1.95%, 06/13/22(a)		300		300,638
2.15%, 09/08/22		1,000		1,008,473
2.80%, 03/06/23		500		513,111
3.45%, 01/10/24		1,000		1,054,183
2.25%, 09/14/26(a)		500		500,292
3.05%, 01/06/28(a)		300		315,063
2.80%, 07/18/29(a)		630		646,768

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Diversified Financial Services (continued)
JPMorgan Chase & Co.:
2.55%, 03/01/21	$	1,000	$	1,007,735
2.40%, 06/07/21		1,000		1,006,596
2.30%, 08/15/21		2,000		2,004,928
4.35%, 08/15/21		500		519,260
4.50%, 01/24/22		1,300		1,365,030
(3 mo. LIBOR US + 0.61%), 3.51%, 06/18/22(c)		2,000		2,043,317
3.25%, 09/23/22		200		206,929
2.97%, 01/15/23		2,000		2,037,858
3.20%, 01/25/23		3,150		3,250,938
(3 mo. LIBOR US + 0.70%), 3.21%, 04/01/23(c)		2,000		2,047,694
(3 mo. LIBOR US + 0.94%), 2.78%, 04/25/23(a)(c)		1,500		1,523,686
3.38%, 05/01/23		250		259,797
2.70%, 05/18/23(a)		500		509,098
(3 mo. LIBOR US + 0.73%), 3.56%, 04/23/24(c)		1,500		1,563,134
3.63%, 05/13/24		1,000		1,060,112
(3 mo. LIBOR US + 0.89%), 3.80%, 07/23/24(c)		4,500		4,743,223
3.88%, 09/10/24		1,300		1,391,747
3.13%, 01/23/25		250		260,909
(3 mo. LIBOR US + 1.16%), 3.22%, 03/01/25(a)(c)		2,000		2,073,558
3.90%, 07/15/25		250		270,019
(Secured Overnight Financing Rate + 1.16%), 2.30%, 10/15/25(c)		500		499,436
3.30%, 04/01/26		500		526,325
3.20%, 06/15/26		1,000		1,044,825
7.63%, 10/15/26		500		645,816
4.13%, 12/15/26(a)		250		273,886
4.25%, 10/01/27(a)		500		553,591
3.63%, 12/01/27		1,000		1,056,533
(3 mo. LIBOR US + 1.34%), 3.78%, 02/01/28(c)		2,000		2,156,770
(3 mo. LIBOR US + 1.38%), 3.54%, 05/01/28(c)		750		796,893
(3 mo. LIBOR US + 0.95%), 3.51%, 01/23/29(c)		1,000		1,062,915
(3 mo. LIBOR US + 1.12%), 4.01%, 04/23/29(a)(c)		4,000		4,393,734
(3 mo. LIBOR US + 1.26%), 4.20%, 07/23/29(c)		175		195,351
(3 mo. LIBOR US + 1.33%), 4.45%, 12/05/29(a)(c)		500		569,046
(3 mo. LIBOR US + 1.16%), 3.70%, 05/06/30(c)		1,000		1,077,382
(Secured Overnight Financing Rate + 1.51%), 2.74%, 10/15/30(c)		1,000		1,000,146
6.40%, 05/15/38(a)		1,100		1,594,088
(3 mo. LIBOR US + 1.36%), 3.88%, 07/24/38(a)(c)		1,000		1,106,934
5.50%, 10/15/40		125		168,190
5.60%, 07/15/41		550		753,246
5.40%, 01/06/42		400		538,562
5.63%, 08/16/43(a)		500		669,753
4.85%, 02/01/44		100		127,865
4.95%, 06/01/45(a)		2,250		2,863,932
(3 mo. LIBOR US + 1.58%), 4.26%, 02/22/48(c)		1,000		1,181,909
(3 mo. LIBOR US + 1.46%), 4.03%, 07/24/48(c)		500		571,489
(3 mo. LIBOR US + 1.38%), 3.96%, 11/15/48(a)(c)		1,500		1,699,670
(3 mo. LIBOR US + 1.22%), 3.90%, 01/23/49(c)		2,000		2,250,953
Lloyds Banking Group PLC:
3.10%, 07/06/21		500		507,886
3.00%, 01/11/22(a)		2,000		2,032,248
(3 mo. LIBOR US + 1.25%), 2.86%, 03/17/23(c)		1,000		1,013,819
4.05%, 08/16/23(a)		500		530,186
3.90%, 03/12/24		500		528,012
4.45%, 05/08/25		500		546,259
4.58%, 12/10/25		250		270,776
4.65%, 03/24/26(a)		250		271,950
4.55%, 08/16/28(a)		2,000		2,240,729
(3 mo. LIBOR US + 1.21%), 3.57%, 11/07/28(c)		500		522,443
5.30%, 12/01/45(a)		250		307,760
4.34%, 01/09/48(a)		1,000		1,082,823
(3 mo. LIBOR US + 0.81%), 2.91%, 11/07/23(a)(c)		1,000		1,015,074

Security	Par (000)		Value
Diversified Financial Services (continued)
Mitsubishi UFJ Financial Group, Inc.:
2.95%, 03/01/21	$	2,000	$	2,021,930
3.00%, 02/22/22(a)		1,500		1,528,847
3.46%, 03/02/23(a)		3,000		3,104,919
3.76%, 07/26/23		1,500		1,580,217
2.80%, 07/18/24(a)		1,000		1,020,305
3.85%, 03/01/26		500		537,099
2.76%, 09/13/26		250		253,365
3.29%, 07/25/27(a)		1,000		1,042,452
3.96%, 03/02/28(a)		1,000		1,090,786
3.74%, 03/07/29		2,000		2,158,468
4.29%, 07/26/38		250		288,757
3.75%, 07/18/39		1,010		1,107,286
Mizuho Financial Group, Inc.:
2.95%, 02/28/22		250		254,581
3.55%, 03/05/23		2,000		2,086,525
(3 mo. LIBOR US + 1.00%), 3.92%, 09/11/24(c)		2,000		2,101,381
(3 mo. LIBOR US + 1.10%), 2.56%, 09/13/25(c)		905		905,261
3.17%, 09/11/27(a)		1,000		1,030,254
(3 mo. LIBOR US + 1.13%), 3.15%, 07/16/30(c)		1,000		1,022,295
(3 mo. LIBOR US + 1.31%), 2.87%, 09/13/30(c)		500		499,589
Moody’s Corp.:
4.50%, 09/01/22		550		581,607
4.88%, 02/15/24(a)		500		549,870
3.25%, 01/15/28		750		786,919
4.25%, 02/01/29(a)		1,000		1,132,635
MUFG Americas Holdings Corp., 3.00%, 02/10/25		200		204,027
National Rural Utilities Cooperative Finance Corp.:
2.90%, 03/15/21(a)		400		404,502
2.30%, 09/15/22(a)		1,000		1,009,027
3.40%, 11/15/23		350		368,453
2.85%, 01/27/25		250		257,390
3.40%, 02/07/28		2,000		2,128,107
4.30%, 03/15/49		500		594,547
Royal Bank of Scotland Group PLC:
6.13%, 12/15/22		1,000		1,094,612
3.88%, 09/12/23		1,000		1,048,034
6.00%, 12/19/23		2,000		2,224,400
(3 mo. LIBOR US + 1.55%), 4.52%, 06/25/24(c)		2,000		2,124,745
4.80%, 04/05/26		500		555,581
(3 mo. LIBOR US + 1.75%), 4.89%, 05/18/29(a)(c)		750		848,415
(5 year CMT + 2.10%), 3.75%, 11/01/29(a)(c)		290		296,185
(3 mo. LIBOR US + 1.91%), 5.08%, 01/27/30(c)		1,000		1,150,378
(3 mo. LIBOR US + 1.87%), 4.45%, 05/08/30(a)(c)		1,000		1,105,004
S&P Global, Inc.:
4.40%, 02/15/26		750		831,820
2.50%, 12/01/29		320		320,246
4.50%, 05/15/48		250		304,743
3.25%, 12/01/49		225		230,270
Sumitomo Mitsui Financial Group, Inc.:
2.93%, 03/09/21		1,500		1,516,191
2.44%, 10/19/21		1,000		1,007,902
2.85%, 01/11/22		1,000		1,015,627
3.10%, 01/17/23		4,000		4,102,837
3.75%, 07/19/23		500		524,587
2.45%, 09/27/24		1,000		1,002,555
3.78%, 03/09/26		500		534,646
2.63%, 07/14/26		1,000		1,000,943
3.01%, 10/19/26		250		256,195
3.36%, 07/12/27		1,000		1,044,276
3.35%, 10/18/27(a)		500		521,716
3.54%, 01/17/28(a)		2,000		2,116,971
3.04%, 07/16/29		920		938,839

SCHEDULE OF INVESTMENTS 29

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Diversified Financial Services (continued)
3.20%, 09/17/29	$	500	$	507,325
2.72%, 09/27/29(a)		1,000		998,430
Toyota Motor Credit Corp.:
1.90%, 04/08/21(a)		900		901,244
2.95%, 04/13/21		500		507,541
2.60%, 01/11/22(a)		250		253,781
3.30%, 01/12/22		2,000		2,057,188
2.63%, 01/10/23		2,000		2,039,346
3.65%, 01/08/29		2,000		2,189,586
				318,947,917
Diversified Telecommunication Services — 0.9%
AT&T, Inc.:
2.80%, 02/17/21		400		403,602
3.20%, 03/01/22		2,000		2,047,490
3.80%, 03/15/22		250		259,502
2.63%, 12/01/22(a)		2,000		2,030,886
3.60%, 02/17/23		500		521,898
3.80%, 03/01/24		1,000		1,061,358
4.45%, 04/01/24(a)		500		542,030
3.95%, 01/15/25		500		535,951
3.40%, 05/15/25		2,500		2,618,181
3.60%, 07/15/25		250		264,638
3.88%, 01/15/26		1,000		1,071,702
4.13%, 02/17/26		1,250		1,354,921
2.95%, 07/15/26		1,500		1,529,227
3.80%, 02/15/27(a)		500		533,016
4.25%, 03/01/27(a)		1,000		1,098,382
4.10%, 02/15/28		1,544		1,680,101
4.35%, 03/01/29(a)		500		556,256
4.30%, 02/15/30(a)		1,000		1,111,191
4.50%, 05/15/35		810		902,605
5.25%, 03/01/37		1,000		1,194,784
4.90%, 08/15/37(a)		750		863,568
4.85%, 03/01/39(a)		2,000		2,306,840
6.00%, 08/15/40		250		320,211
5.35%, 09/01/40		463		558,826
6.25%, 03/29/41(a)		150		195,336
5.55%, 08/15/41		200		244,742
5.38%, 10/15/41		1,500		1,784,907
5.15%, 03/15/42		150		175,273
4.90%, 06/15/42		350		399,600
4.30%, 12/15/42		651		697,426
5.35%, 12/15/43		250		296,419
4.65%, 06/01/44		250		273,278
4.80%, 06/15/44		750		855,746
4.35%, 06/15/45		2,759		2,978,650
4.85%, 07/15/45		500		571,079
4.75%, 05/15/46		1,000		1,131,743
5.15%, 11/15/46		1,952		2,337,214
5.65%, 02/15/47(a)		250		318,545
5.45%, 03/01/47		750		931,705
4.50%, 03/09/48(a)		3,250		3,590,594
4.55%, 03/09/49(a)		2,000		2,221,030
5.15%, 02/15/50		500		603,278
5.70%, 03/01/57		500		645,637
British Telecommunications PLC:
5.13%, 12/04/28		1,000		1,149,677
9.63%, 12/15/30		900		1,384,147
Deutsche Telekom International Finance BV, 8.75%, 06/15/30		1,650		2,430,785
Orange SA(a):
9.00%, 03/01/31		250		387,258
5.38%, 01/13/42		1,825		2,350,874

Security	Par (000)		Value
Diversified Telecommunication Services (continued)
Telefonica Emisiones SAU:
5.46%, 02/16/21	$	1,050	$	1,089,793
4.57%, 04/27/23(a)		1,200		1,291,372
4.10%, 03/08/27		1,000		1,082,522
7.05%, 06/20/36		75		104,981
4.67%, 03/06/38		1,000		1,118,794
5.21%, 03/08/47		1,750		2,077,085
4.90%, 03/06/48(a)		500		572,519
5.52%, 03/01/49		500		627,286
Telefonica Europe BV, 8.25%, 09/15/30		300		431,024
Verizon Communications, Inc.:
4.15%, 03/15/24(a)		2,000		2,157,280
3.50%, 11/01/24		500		530,236
3.38%, 02/15/25		3,992		4,228,760
2.63%, 08/15/26		900		914,037
4.13%, 03/16/27(a)		750		832,679
4.33%, 09/21/28		3,164		3,591,042
3.88%, 02/08/29		3,000		3,309,341
4.02%, 12/03/29		1,500		1,672,118
4.50%, 08/10/33		1,750		2,042,793
4.40%, 11/01/34		2,500		2,898,141
4.27%, 01/15/36		1,250		1,415,691
5.25%, 03/16/37		1,250		1,569,912
4.81%, 03/15/39(a)		596		719,470
3.85%, 11/01/42		250		270,158
6.55%, 09/15/43(a)		750		1,101,199
4.86%, 08/21/46		1,500		1,862,093
5.50%, 03/16/47		250		339,470
4.52%, 09/15/48		4,250		5,099,768
5.01%, 04/15/49		1,981		2,539,871
				98,811,544
Electric Utilities — 1.6%
AEP Texas, Inc.:
2.40%, 10/01/22		2,000		2,018,669
3.95%, 06/01/28		500		543,724
Series H, 3.45%, 01/15/50		250		250,239
AEP Transmission Co. LLC:
3.10%, 12/01/26(a)		500		518,172
3.80%, 06/15/49(a)		1,000		1,070,154
3.15%, 09/15/49		135		130,624
Alabama Power Co.:
3.75%, 03/01/45		250		265,033
4.30%, 01/02/46		250		285,859
3.45%, 10/01/49		185		189,812
Series B, 3.70%, 12/01/47(a)		2,500		2,641,237
Ameren Corp., 2.50%, 09/15/24		635		637,833
Ameren Illinois Co.:
2.70%, 09/01/22		100		101,789
4.30%, 07/01/44		250		285,166
3.25%, 03/15/50		150		151,906
American Electric Power Co., Inc., Series F, 2.95%, 12/15/22		500		509,553
Appalachian Power Co., 4.40%, 05/15/44		250		282,541
Arizona Public Service Co.:
3.15%, 05/15/25(a)		250		259,258
2.60%, 08/15/29(a)		1,000		991,603
5.05%, 09/01/41		250		304,092
4.20%, 08/15/48		250		283,522
3.50%, 12/01/49		1,100		1,109,306
Baltimore Gas & Electric Co.:
2.40%, 08/15/26		1,000		992,884
3.50%, 08/15/46		700		712,918
3.20%, 09/15/49(a)		225		220,529

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Electric Utilities (continued)
Berkshire Hathaway Energy Co.:
2.38%, 01/15/21	$	2,000	$	2,010,690
3.75%, 11/15/23		500		531,135
3.50%, 02/01/25		110		116,789
3.25%, 04/15/28(a)		1,000		1,057,310
6.13%, 04/01/36		250		343,426
5.15%, 11/15/43		250		316,645
4.50%, 02/01/45(a)		400		471,517
4.45%, 01/15/49		2,000		2,380,414
Black Hills Corp.:
3.95%, 01/15/26		200		210,621
3.05%, 10/15/29		415		413,516
4.35%, 05/01/33(a)		400		444,045
3.88%, 10/15/49(a)		350		349,773
CenterPoint Energy Houston Electric LLC:
1.85%, 06/01/21(a)		500		499,892
3.55%, 08/01/42		100		105,161
3.95%, 03/01/48		250		280,853
Cleco Corporate Holdings LLC:
3.74%, 05/01/26(a)		500		516,691
3.38%, 09/15/29(b)		1,000		1,004,308
CMS Energy Corp.:
3.45%, 08/15/27		1,000		1,046,553
4.70%, 03/31/43		200		225,583
Commonwealth Edison Co.:
3.10%, 11/01/24(a)		250		259,515
2.55%, 06/15/26		250		253,071
3.70%, 08/15/28		500		547,040
5.90%, 03/15/36		50		66,375
3.70%, 03/01/45		250		266,151
3.65%, 06/15/46		1,000		1,062,143
4.00%, 03/01/48		2,000		2,250,744
Series 122, 2.95%, 08/15/27(a)		1,000		1,036,283
Series 127, 3.20%, 11/15/49		610		607,326
Connecticut Light & Power Co.:
2.50%, 01/15/23		150		152,193
Series A, 3.20%, 03/15/27		500		528,243
Consolidated Edison Co. of New York, Inc.:
3.30%, 12/01/24(a)		250		262,514
3.80%, 05/15/28(a)		1,000		1,089,097
3.95%, 03/01/43		150		162,485
4.45%, 03/15/44		250		290,500
4.50%, 05/15/58(a)		1,000		1,162,886
3.70%, 11/15/59		200		206,676
Series A, 4.20%, 03/15/42		400		446,393
Series A, 4.13%, 05/15/49		500		568,207
Series C, 4.30%, 12/01/56		500		564,723
Series C, 4.00%, 11/15/57		750		804,175
Series D, 4.00%, 12/01/28(a)		500		555,601
Series E, 4.65%, 12/01/48(a)		500		608,627
Consolidated Edison, Inc., 2.00%, 05/15/21		750		750,483
Consumers Energy Co.(a):
4.35%, 04/15/49		1,000		1,214,029
3.10%, 08/15/50		215		214,621
Dominion Energy South Carolina, Inc.:
5.45%, 02/01/41		1,000		1,300,917
4.60%, 06/15/43		250		296,896
Dominion Energy, Inc.:
3.07%, 08/15/24(a)(d)		500		515,084
3.90%, 10/01/25		2,000		2,148,900
7.00%, 06/15/38		250		347,190
Series C, 4.90%, 08/01/41		50		58,673
DTE Electric Co.:
3.65%, 03/15/24		1,000		1,058,706

Security	Par (000)		Value
Electric Utilities (continued)
3.70%, 03/15/45	$	645	$	696,378
3.70%, 06/01/46(a)		250		270,434
3.75%, 08/15/47		200		218,899
Series A, 4.00%, 04/01/43		150		168,439
Series A, 4.05%, 05/15/48(a)		250		290,260
DTE Energy Co.:
2.25%, 11/01/22		200		199,985
2.95%, 03/01/30		1,500		1,485,452
Series C, 2.53%, 10/01/24		1,000		1,004,879
Series C, 3.40%, 06/15/29		1,225		1,263,055
Duke Energy Carolinas LLC:
3.05%, 03/15/23		200		206,153
2.45%, 08/15/29(a)		1,000		993,283
6.10%, 06/01/37		500		680,287
6.05%, 04/15/38		100		138,359
5.30%, 02/15/40		250		323,812
4.25%, 12/15/41		2,000		2,286,899
3.70%, 12/01/47		500		538,099
3.95%, 03/15/48		1,000		1,122,831
3.20%, 08/15/49		595		593,024
Duke Energy Corp.:
1.80%, 09/01/21		3,000		2,997,571
2.40%, 08/15/22		1,000		1,010,175
3.95%, 10/15/23		250		265,282
3.75%, 04/15/24(a)		500		529,957
2.65%, 09/01/26		500		502,435
3.15%, 08/15/27(a)		500		515,294
4.80%, 12/15/45		250		296,493
3.75%, 09/01/46		500		517,223
3.95%, 08/15/47(a)		500		529,659
4.20%, 06/15/49		500		552,861
Duke Energy Florida LLC:
2.50%, 12/01/29		345		344,086
3.40%, 10/01/46(a)		250		254,744
Duke Energy Indiana LLC:
3.75%, 05/15/46		500		537,297
Series UUU, 4.20%, 03/15/42		400		443,519
Series WWW, 4.90%, 07/15/43(a)		250		308,430
Series YYY, 3.25%, 10/01/49		500		500,067
Duke Energy Ohio, Inc., 3.70%, 06/15/46		250		265,483
Duke Energy Progress LLC:
3.38%, 09/01/23		250		261,238
3.70%, 09/01/28		365		398,279
4.10%, 05/15/42		150		169,788
4.10%, 03/15/43		250		280,116
4.38%, 03/30/44		100		116,190
4.20%, 08/15/45		250		284,763
3.70%, 10/15/46		500		535,371
Edison International:
3.13%, 11/15/22		95		96,493
3.55%, 11/15/24		175		179,261
5.75%, 06/15/27(a)		50		56,140
Emera US Finance LP:
2.70%, 06/15/21		1,000		1,009,307
3.55%, 06/15/26		75		77,915
4.75%, 06/15/46		350		405,248
Entergy Arkansas LLC, 3.50%, 04/01/26(a)		65		68,573
Entergy Corp., 4.00%, 07/15/22		200		208,783
Entergy Louisiana LLC:
4.05%, 09/01/23(a)		250		265,836
5.40%, 11/01/24		3,000		3,436,070
4.00%, 03/15/33		250		282,913
4.20%, 09/01/48		250		289,385
4.20%, 04/01/50		1,000		1,160,390

SCHEDULE OF INVESTMENTS 31

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Electric Utilities (continued)
Entergy Mississippi LLC, 2.85%, 06/01/28	$	500	$	511,496
Entergy Texas, Inc., 3.55%, 09/30/49		200		203,803
Evergy Kansas Central, Inc.:
2.55%, 07/01/26		350		351,081
4.25%, 12/01/45		1,000		1,140,530
3.25%, 09/01/49		500		492,625
Evergy Metro, Inc., 3.65%, 08/15/25		150		160,018
Evergy, Inc.:
2.45%, 09/15/24		500		502,969
2.90%, 09/15/29		500		497,651
Eversource Energy:
2.50%, 03/15/21(a)		500		502,933
Series H, 3.15%, 01/15/25		125		128,999
Series M, 3.30%, 01/15/28		2,000		2,061,216
Exelon Corp.:
3.50%, 06/01/22		500		513,523
3.95%, 06/15/25		250		268,964
3.40%, 04/15/26		750		783,637
5.10%, 06/15/45(a)		250		301,523
4.45%, 04/15/46		250		281,069
Exelon Generation Co. LLC:
4.25%, 06/15/22		500		522,991
6.25%, 10/01/39		150		180,583
5.75%, 10/01/41		500		577,546
5.60%, 06/15/42		50		57,208
FirstEnergy Corp.:
Series B, 3.90%, 07/15/27		2,000		2,139,348
Series C, 4.85%, 07/15/47		500		594,816
Florida Power & Light Co.:
2.75%, 06/01/23		250		256,281
3.13%, 12/01/25		500		525,389
5.95%, 02/01/38(a)		50		69,281
5.25%, 02/01/41		500		646,687
4.13%, 02/01/42		500		573,079
4.05%, 10/01/44(a)		750		855,712
3.70%, 12/01/47(a)		1,000		1,092,109
3.95%, 03/01/48		500		570,620
4.13%, 06/01/48(a)		500		585,884
3.15%, 10/01/49		885		895,196
Georgia Power Co.:
4.30%, 03/15/42		700		768,125
Series A, 2.20%, 09/15/24		1,000		1,000,128
Series B, 2.65%, 09/15/29		1,000		986,963
Indiana Michigan Power Co.:
6.05%, 03/15/37		175		229,126
4.25%, 08/15/48		250		286,165
Series K, 4.55%, 03/15/46		150		175,194
Interstate Power & Light Co.:
3.25%, 12/01/24		250		260,366
3.70%, 09/15/46		500		507,900
3.50%, 09/30/49		105		103,023
ITC Holdings Corp., 3.25%, 06/30/26		1,000		1,031,759
Louisville Gas & Electric Co., 4.65%, 11/15/43(a)		250		294,687
MidAmerican Energy Co.:
3.65%, 04/15/29		500		546,780
4.80%, 09/15/43		250		309,249
4.40%, 10/15/44		1,000		1,180,043
4.25%, 07/15/49(a)		1,500		1,800,791
3.15%, 04/15/50		250		246,954
Mississippi Power Co., Series A, 4.25%, 03/15/42		500		537,623
Nevada Power Co., 5.45%, 05/15/41(a)		50		63,926
NextEra Energy Capital Holdings, Inc.:
2.80%, 01/15/23		1,000		1,022,291
3.63%, 06/15/23		1,250		1,307,072

Security	Par (000)		Value
Electric Utilities (continued)
3.15%, 04/01/24	$	500	$	518,541
3.55%, 05/01/27		1,000		1,062,497
2.75%, 11/01/29		245		246,307
Northern States Power Co.:
2.60%, 05/15/23		500		507,870
3.40%, 08/15/42		200		209,408
4.00%, 08/15/45		85		96,501
3.60%, 09/15/47		150		160,613
2.90%, 03/01/50(a)		445		425,136
NSTAR Electric Co., 2.70%, 06/01/26(a)		250		253,448
Oglethorpe Power Corp.:
4.55%, 06/01/44		250		262,583
5.05%, 10/01/48		500		589,057
Ohio Power Co., 4.15%, 04/01/48(a)		1,000		1,129,989
Oncor Electric Delivery Co. LLC:
7.00%, 09/01/22		100		111,752
3.70%, 11/15/28		355		388,610
5.25%, 09/30/40		250		320,666
5.30%, 06/01/42		75		98,157
3.75%, 04/01/45		250		271,843
3.80%, 09/30/47		1,000		1,103,904
3.10%, 09/15/49		245		239,473
PacifiCorp:
2.95%, 02/01/22		100		101,960
2.95%, 06/01/23		300		308,256
4.10%, 02/01/42		250		279,072
PECO Energy Co.:
1.70%, 09/15/21		1,000		998,780
3.90%, 03/01/48(a)		1,000		1,127,461
3.00%, 09/15/49		195		187,419
Pennsylvania Electric Co., 6.15%, 10/01/38		250		324,199
Potomac Electric Power Co.:
3.60%, 03/15/24		250		263,460
4.15%, 03/15/43		250		282,547
PPL Capital Funding, Inc.:
3.50%, 12/01/22		2,000		2,069,844
3.40%, 06/01/23		1,250		1,290,618
5.00%, 03/15/44		1,000		1,149,720
4.00%, 09/15/47		500		512,040
PPL Electric Utilities Corp.:
4.75%, 07/15/43		250		302,083
3.00%, 10/01/49		170		162,545
Progress Energy, Inc.:
4.40%, 01/15/21		100		101,955
7.75%, 03/01/31(a)		50		70,415
Public Service Co. of Colorado:
3.70%, 06/15/28		2,000		2,182,171
3.60%, 09/15/42		250		264,336
3.95%, 03/15/43(a)		200		215,957
4.30%, 03/15/44		75		87,461
3.80%, 06/15/47		1,000		1,088,126
Public Service Co. of New Hampshire, 3.60%, 07/01/49		1,000		1,068,813
Public Service Co. of Oklahoma, Series G, 6.63%, 11/15/37		250		346,270
Public Service Electric & Gas Co.:
2.38%, 05/15/23		250		253,368
3.05%, 11/15/24(a)		250		259,359
3.20%, 05/15/29(a)		500		527,537
3.95%, 05/01/42		50		55,484
3.65%, 09/01/42		50		53,447
3.80%, 03/01/46(a)		1,250		1,378,842
3.85%, 05/01/49		500		563,267
Series K, 4.05%, 05/01/45(a)		150		167,092

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Electric Utilities (continued)
Puget Energy, Inc.:
5.63%, 07/15/22	$	500	$	536,416
3.65%, 05/15/25		250		258,965
Puget Sound Energy, Inc.:
5.80%, 03/15/40(a)		500		665,400
4.22%, 06/15/48		500		576,259
3.25%, 09/15/49		1,000		996,489
Sierra Pacific Power Co., 2.60%, 05/01/26(a)		1,250		1,257,038
Southern California Edison Co.:
2.85%, 08/01/29(a)		2,000		1,998,183
5.50%, 03/15/40		50		61,752
4.50%, 09/01/40		1,000		1,098,653
4.65%, 10/01/43		350		397,111
4.00%, 04/01/47		500		526,426
Series A, 5.95%, 02/01/38(a)		500		634,305
Series B, 2.40%, 02/01/22		250		251,304
Series C, 3.60%, 02/01/45		250		248,649
Series C, 4.13%, 03/01/48		1,000		1,068,506
Series D, 3.40%, 06/01/23		1,000		1,036,973
Series E, 3.70%, 08/01/25(a)		2,000		2,118,499
Southern Co.:
2.35%, 07/01/21		1,000		1,005,058
2.95%, 07/01/23		500		512,905
3.25%, 07/01/26		500		520,946
4.40%, 07/01/46		250		277,266
Southern Power Co.:
5.25%, 07/15/43(a)		500		573,009
Series E, 2.50%, 12/15/21		1,000		1,010,411
Southwestern Electric Power Co., Series L, 3.85%, 02/01/48		500		519,885
Southwestern Public Service Co., 3.75%, 06/15/49		1,000		1,076,009
Tampa Electric Co.:
4.10%, 06/15/42		250		272,470
4.45%, 06/15/49		250		296,446
3.63%, 06/15/50(a)		80		84,438
Toledo Edison Co., 6.15%, 05/15/37		100		137,324
Tucson Electric Power Co., 4.85%, 12/01/48		250		305,168
Union Electric Co.:
2.95%, 06/15/27		2,000		2,061,311
4.00%, 04/01/48		1,000		1,109,877
3.25%, 10/01/49		500		496,593
Virginia Electric & Power Co.:
2.95%, 01/15/22		400		406,997
4.00%, 01/15/43		250		276,437
4.45%, 02/15/44		150		174,275
4.60%, 12/01/48(a)		455		557,905
3.30%, 12/01/49		280		282,722
Series A, 3.15%, 01/15/26		555		580,244
Series A, 3.50%, 03/15/27(a)		750		802,345
Series A, 2.88%, 07/15/29		115		117,846
Series A, 6.00%, 05/15/37		250		337,897
Series B, 6.00%, 01/15/36		1,000		1,329,481
Series B, 3.80%, 09/15/47		1,500		1,623,769
Series D, 4.65%, 08/15/43		500		598,049
WEC Energy Group, Inc., 3.55%, 06/15/25		350		371,644
Wisconsin Electric Power Co., 4.30%, 10/15/48(a)		750		881,811
Wisconsin Power & Light Co., 3.00%, 07/01/29		1,000		1,032,573
Wisconsin Public Service Corp., 3.30%, 09/01/49		625		626,590
Xcel Energy, Inc.:
3.30%, 06/01/25		292		304,954
3.35%, 12/01/26(a)		500		524,818
4.00%, 06/15/28		1,000		1,099,218
2.60%, 12/01/29		200		198,220

Security	Par (000)		Value
Electric Utilities (continued)
4.80%, 09/15/41	$	250	$	282,133
3.50%, 12/01/49		200		203,341
				175,317,479
Electrical Equipment — 0.1%
Eaton Corp.:
2.75%, 11/02/22		2,250		2,295,907
3.10%, 09/15/27		190		197,465
4.00%, 11/02/32		200		226,912
4.15%, 11/02/42(a)		250		279,754
Emerson Electric Co.:
2.63%, 12/01/21		750		762,751
2.63%, 02/15/23		350		359,226
Rockwell Automation, Inc., 4.20%, 03/01/49		1,000		1,168,339
Roper Technologies, Inc.:
3.13%, 11/15/22(a)		150		153,742
3.65%, 09/15/23		250		262,531
2.35%, 09/15/24(a)		240		241,377
3.80%, 12/15/26(a)		250		268,723
2.95%, 09/15/29(a)		435		439,430
Tyco Electronics Group SA:
3.50%, 02/03/22		100		102,851
3.45%, 08/01/24		75		78,598
				6,837,606
Electronic Equipment, Instruments & Components — 0.1%
Amphenol Corp., 2.80%, 02/15/30(a)		1,000		990,670
Arrow Electronics, Inc., 4.00%, 04/01/25(a)		500		527,164
Avnet, Inc., 3.75%, 12/01/21		1,000		1,026,306
Corning, Inc.:
3.70%, 11/15/23		250		260,586
4.75%, 03/15/42		50		56,808
5.35%, 11/15/48(a)		1,000		1,255,124
3.90%, 11/15/49		250		253,661
4.38%, 11/15/57		750		769,644
5.45%, 11/15/79		250		273,907
Flex Ltd., 4.88%, 06/15/29		500		544,222
Honeywell International, Inc.:
1.85%, 11/01/21(a)		4,000		4,009,217
2.30%, 08/15/24		1,000		1,012,291
2.70%, 08/15/29		1,500		1,535,304
3.81%, 11/21/47(a)		500		568,889
Jabil, Inc., 4.70%, 09/15/22(a)		250		264,947
Keysight Technologies, Inc., 3.00%, 10/30/29		800		802,658
				14,151,398
Energy Equipment & Services — 0.1%
Baker Hughes a GE Co. LLC, 5.13%, 09/15/40(a)		100		117,823
Baker Hughes a GE Co. LLC/Baker HughesCo-Obligor, Inc.:
2.77%, 12/15/22		500		510,039
3.34%, 12/15/27		450		469,773
3.14%, 11/07/29		325		334,653
4.08%, 12/15/47		1,500		1,538,260
Halliburton Co.:
3.80%, 11/15/25		4,550		4,853,898
4.85%, 11/15/35		1,000		1,131,463
4.50%, 11/15/41(a)		50		53,133
4.75%, 08/01/43		250		278,012
5.00%, 11/15/45		1,175		1,343,179
National Oilwell Varco, Inc.:
2.60%, 12/01/22		786		793,552
3.60%, 12/01/29		1,000		1,003,049
3.95%, 12/01/42		150		138,230
TechnipFMC PLC, 3.45%, 10/01/22		100		102,155
				12,667,219

SCHEDULE OF INVESTMENTS 33

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Equity Real Estate Investment Trusts (REITs) — 0.8%
Alexandria Real Estate Equities, Inc.:
3.90%, 06/15/23(a)	$	2,000	$	2,101,199
4.30%, 01/15/26(a)		750		823,393
3.38%, 08/15/31		820		852,386
4.00%, 02/01/50		1,000		1,095,863
American Campus Communities Operating Partnership LP, 3.30%, 07/15/26(a)		1,000		1,036,539
American Tower Corp.:
2.75%, 01/15/27		435		434,526
3.70%, 10/15/49		425		423,579
5.90%, 11/01/21(a)		500		533,973
4.70%, 03/15/22		100		105,379
3.50%, 01/31/23		150		155,450
3.00%, 06/15/23		1,000		1,022,118
5.00%, 02/15/24		1,000		1,099,868
2.95%, 01/15/25		500		510,962
4.40%, 02/15/26		30		32,738
3.38%, 10/15/26		500		519,880
3.95%, 03/15/29(a)		1,000		1,075,604
3.80%, 08/15/29(a)		500		534,565
AvalonBay Communities, Inc.:
2.95%, 09/15/22		100		102,434
3.45%, 06/01/25		100		105,705
3.20%, 01/15/28		2,000		2,088,465
3.30%, 06/01/29		255		269,750
3.90%, 10/15/46(a)		250		274,380
Boston Properties LP:
4.13%, 05/15/21		250		255,867
3.85%, 02/01/23		1,000		1,047,885
3.13%, 09/01/23		250		258,027
3.20%, 01/15/25		1,000		1,038,091
3.65%, 02/01/26		190		201,359
4.50%, 12/01/28		1,000		1,133,992
2.90%, 03/15/30		480		479,229
Brixmor Operating Partnership LP:
3.65%, 06/15/24(a)		750		784,557
4.13%, 06/15/26		250		266,366
4.13%, 05/15/29		1,250		1,342,978
Choice Hotels International, Inc., 3.70%, 12/01/29		200		201,458
Crown Castle International Corp.:
3.40%, 02/15/21		750		760,206
2.25%, 09/01/21		1,000		1,002,907
3.70%, 06/15/26		280		296,002
4.00%, 03/01/27(a)		1,000		1,079,827
3.80%, 02/15/28(a)		2,000		2,131,980
4.00%, 11/15/49		585		605,636
CubeSmart LP, 3.00%, 02/15/30		1,500		1,483,253
Digital Realty Trust LP:
4.75%, 10/01/25(a)		500		555,695
3.70%, 08/15/27		1,000		1,059,738
3.60%, 07/01/29		750		780,720
Duke Realty LP, 2.88%, 11/15/29		540		541,539
EPR Properties:
4.50%, 06/01/27		1,000		1,070,628
3.75%, 08/15/29(a)		845		856,657
ERP Operating LP:
4.63%, 12/15/21		2,000		2,089,618
3.00%, 04/15/23(a)		500		514,956
3.25%, 08/01/27(a)		500		525,671
3.50%, 03/01/28(a)		1,000		1,066,906
3.00%, 07/01/29(a)		735		761,399
2.50%, 02/15/30(a)		405		402,142
4.50%, 07/01/44		150		178,335

Security	Par (000)		Value
Equity Real Estate Investment Trusts (REITs) (continued)
Essex Portfolio LP:
3.88%, 05/01/24(a)	$	100	$	105,725
4.00%, 03/01/29(a)		2,000		2,173,377
3.00%, 01/15/30		200		202,419
Federal Realty Investment Trust, 3.25%, 07/15/27		500		518,431
Healthcare Trust of America Holdings LP, 3.10%, 02/15/30		1,000		993,152
Healthpeak Properties, Inc.:
3.15%, 08/01/22		100		102,372
3.40%, 02/01/25		500		522,213
4.00%, 06/01/25		500		537,610
3.50%, 07/15/29		1,500		1,564,687
3.00%, 01/15/30		530		532,094
Host Hotels & Resorts LP:
Series E, 4.00%, 06/15/25		190		203,482
Series H, 3.38%, 12/15/29		1,000		1,009,041
Hudson Pacific Properties LP, 4.65%, 04/01/29		1,000		1,100,893
Kilroy Realty LP(a):
4.75%, 12/15/28		1,000		1,134,824
3.05%, 02/15/30		1,000		986,298
Kimco Realty Corp.:
3.20%, 05/01/21		250		253,529
3.30%, 02/01/25		350		364,341
2.80%, 10/01/26(a)		500		502,640
4.45%, 09/01/47		350		383,990
3.70%, 10/01/49		500		486,805
Liberty Property LP, 4.40%, 02/15/24(a)		250		270,305
Life Storage LP, 4.00%, 06/15/29(a)		1,000		1,070,962
Mid-America Apartments LP(a):
4.30%, 10/15/23		200		214,047
3.95%, 03/15/29		500		545,672
National Retail Properties, Inc.:
3.30%, 04/15/23(a)		500		514,758
4.30%, 10/15/28		1,000		1,106,783
Omega Healthcare Investors, Inc.:
4.50%, 04/01/27(a)		250		269,903
4.75%, 01/15/28(a)		500		544,594
3.63%, 10/01/29		600		600,725
Realty Income Corp.:
4.65%, 08/01/23		250		270,591
4.13%, 10/15/26		1,000		1,097,392
3.00%, 01/15/27		1,000		1,029,124
3.25%, 06/15/29(a)		975		1,029,881
Sabra Health Care LP/Sabra Capital Corp., 3.90%, 10/15/29		1,000		1,005,700
Service Properties Trust:
5.00%, 08/15/22(a)		200		210,424
4.95%, 02/15/27(a)		1,000		1,037,204
4.35%, 10/01/24		1,000		1,027,684
Simon Property Group LP:
2.35%, 01/30/22		2,000		2,017,822
2.63%, 06/15/22		250		253,950
2.00%, 09/13/24		1,040		1,035,016
3.38%, 10/01/24(a)		500		526,619
3.30%, 01/15/26(a)		1,500		1,579,151
3.38%, 06/15/27(a)		750		793,891
2.45%, 09/13/29		500		492,240
4.75%, 03/15/42		100		120,130
4.25%, 10/01/44		250		283,180
4.25%, 11/30/46(a)		500		572,080
3.25%, 09/13/49		655		637,340
SITE Centers Corp.:
4.63%, 07/15/22		32		33,377
4.25%, 02/01/26		250		263,865

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Equity Real Estate Investment Trusts (REITs) (continued)
Spirit Realty LP:
4.00%, 07/15/29	$	425	$	447,602
3.40%, 01/15/30		500		502,631
UDR, Inc.:
4.40%, 01/26/29(a)		1,000		1,116,937
3.20%, 01/15/30		500		511,437
3.00%, 08/15/31		500		500,979
Ventas Realty LP:
2.65%, 01/15/25		650		654,904
4.13%, 01/15/26		1,250		1,339,169
3.25%, 10/15/26		500		511,978
4.00%, 03/01/28(a)		1,500		1,608,874
3.00%, 01/15/30(a)		1,000		991,467
VEREIT Operating Partnership LP, 3.95%, 08/15/27		500		525,796
Welltower, Inc.:
4.00%, 06/01/25		2,250		2,422,494
4.25%, 04/01/26		350		381,134
4.13%, 03/15/29(a)		1,000		1,090,060
3.10%, 01/15/30(a)		1,000		1,012,712
Weyerhaeuser Co.:
4.00%, 11/15/29(a)		2,000		2,165,168
7.38%, 03/15/32		350		484,008
WP Carey, Inc., 3.85%, 07/15/29		475		501,684
				90,873,747
Food & Staples Retailing — 0.3%
Koninklijke Ahold Delhaize NV, 5.70%, 10/01/40(a)		73		90,142
Kroger Co.:
3.30%, 01/15/21		500		506,477
3.40%, 04/15/22		100		102,841
3.50%, 02/01/26(a)		495		521,952
2.65%, 10/15/26(a)		1,000		1,006,827
3.70%, 08/01/27		500		535,484
4.50%, 01/15/29(a)		1,000		1,125,145
5.15%, 08/01/43(a)		125		143,493
3.88%, 10/15/46(a)		500		489,891
4.65%, 01/15/48		500		547,280
5.40%, 01/15/49		500		610,820
Mondelez International, Inc.:
3.63%, 05/07/23(a)		500		524,279
4.63%, 05/07/48		500		577,234
Walgreen Co., 3.10%, 09/15/22		200		204,179
Walgreens Boots Alliance, Inc.:
3.30%, 11/18/21		500		509,482
3.80%, 11/18/24(a)		1,000		1,042,401
3.45%, 06/01/26		1,305		1,327,763
4.50%, 11/18/34		155		161,709
4.80%, 11/18/44(a)		150		152,008
4.65%, 06/01/46		1,000		1,005,745
Walmart, Inc.:
3.13%, 06/23/21(a)		4,500		4,596,217
2.35%, 12/15/22		1,250		1,271,879
3.30%, 04/22/24		1,750		1,840,552
2.85%, 07/08/24		2,500		2,593,866
2.65%, 12/15/24(a)		250		258,171
3.70%, 06/26/28		1,000		1,101,793
3.25%, 07/08/29		250		268,330
2.38%, 09/24/29(a)		275		275,326
3.95%, 06/28/38(a)		1,000		1,158,439
4.88%, 07/08/40(a)		2,000		2,517,968
4.00%, 04/11/43		150		171,447
4.30%, 04/22/44		750		891,499
3.63%, 12/15/47		1,000		1,113,050

Security	Par (000)		Value
Food & Staples Retailing (continued)
4.05%, 06/29/48	$	1,900	$	2,252,154
2.95%, 09/24/49		495		493,188
				31,989,031
Food Products — 0.3%
Archer-Daniels-Midland Co.:
2.50%, 08/11/26		1,750		1,775,793
4.54%, 03/26/42		75		88,765
4.02%, 04/16/43		250		276,297
4.50%, 03/15/49		1,000		1,222,541
Bunge, Ltd. Finance Corp., 3.75%, 09/25/27		1,000		1,022,296
Campbell Soup Co.:
3.65%, 03/15/23		1,000		1,041,840
3.30%, 03/19/25(a)		1,000		1,030,579
4.80%, 03/15/48(a)		1,000		1,158,345
Conagra Brands, Inc.:
3.25%, 09/15/22		200		204,863
3.20%, 01/25/23		500		515,361
4.30%, 05/01/24(a)		1,000		1,077,006
4.60%, 11/01/25(a)		1,000		1,104,822
5.30%, 11/01/38		1,000		1,187,625
5.40%, 11/01/48(a)		500		610,704
General Mills, Inc.:
3.15%, 12/15/21(a)		650		664,576
2.60%, 10/12/22(a)		250		253,833
3.65%, 02/15/24		500		525,684
3.20%, 02/10/27(a)		250		263,450
4.20%, 04/17/28(a)		1,000		1,114,720
4.15%, 02/15/43		300		322,504
4.70%, 04/17/48		1,000		1,193,073
JM Smucker Co.:
3.50%, 10/15/21		50		51,291
3.50%, 03/15/25(a)		1,250		1,315,769
4.25%, 03/15/35(a)		250		270,760
4.38%, 03/15/45		500		539,764
Kellogg Co.(a):
3.25%, 04/01/26		65		67,604
4.30%, 05/15/28		1,000		1,107,502
4.50%, 04/01/46		350		390,740
Kraft Heinz Foods Co.:
3.95%, 07/15/25(a)		1,750		1,853,082
3.00%, 06/01/26		310		310,090
4.63%, 01/30/29		1,000		1,100,198
3.75%, 04/01/30(a)(b)		250		257,616
5.00%, 07/15/35		500		555,527
6.50%, 02/09/40		750		910,426
5.00%, 06/04/42		200		213,704
5.20%, 07/15/45		1,000		1,085,950
4.38%, 06/01/46		2,500		2,464,424
4.88%, 10/01/49(a)(b)		750		791,622
Sysco Corp.:
3.55%, 03/15/25		1,000		1,064,852
3.75%, 10/01/25		100		107,575
3.30%, 07/15/26		130		137,093
4.85%, 10/01/45(a)		150		180,287
4.50%, 04/01/46		250		285,743
4.45%, 03/15/48(a)		500		569,484
Tyson Foods, Inc.:
4.50%, 06/15/22		150		157,943
3.55%, 06/02/27		1,000		1,063,292
4.88%, 08/15/34		70		83,564
5.15%, 08/15/44		250		305,235
5.10%, 09/28/48		1,500		1,888,738
				35,784,552

SCHEDULE OF INVESTMENTS 35

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Forest Products — 0.0%
Hershey Co.:
2.05%, 11/15/24	$	500	$	501,216
2.45%, 11/15/29		500		502,920
3.13%, 11/15/49		500		495,898
				1,500,034
Gas Utilities — 0.1%
Atmos Energy Corp.:
3.00%, 06/15/27		500		516,066
2.63%, 09/15/29(a)		210		212,029
4.15%, 01/15/43(a)		100		112,242
4.30%, 10/01/48		500		586,017
4.13%, 03/15/49		500		574,634
3.38%, 09/15/49		630		639,784
National Fuel Gas Co., 3.75%, 03/01/23		300		309,695
NiSource, Inc.:
3.65%, 06/15/23		1,000		1,041,718
2.95%, 09/01/29		1,000		996,671
5.95%, 06/15/41		1,050		1,345,871
5.25%, 02/15/43		75		91,291
4.80%, 02/15/44		250		290,784
4.38%, 05/15/47		500		554,738
Sempra Energy:
4.05%, 12/01/23		250		265,879
3.55%, 06/15/24		250		261,904
3.75%, 11/15/25		250		264,615
3.40%, 02/01/28(a)		2,000		2,073,365
4.00%, 02/01/48(a)		1,000		1,051,111
Southern California Gas Co.(a):
Series TT, 2.60%, 06/15/26		1,250		1,252,894
Series UU, 4.13%, 06/01/48		250		278,337
Southern Co. Gas Capital Corp.:
3.50%, 09/15/21(a)		50		51,033
2.45%, 10/01/23(a)		1,000		1,007,041
3.95%, 10/01/46		750		775,933
				14,553,652
Health Care Equipment & Supplies — 0.2%
Baxter International, Inc.:
1.70%, 08/15/21		1,000		998,548
2.60%, 08/15/26		730		736,660
Becton Dickinson & Co.:
2.89%, 06/06/22		500		508,326
3.30%, 03/01/23		200		204,282
3.36%, 06/06/24		1,000		1,041,541
3.73%, 12/15/24		1,250		1,325,220
3.70%, 06/06/27		1,630		1,734,646
6.00%, 05/15/39		250		309,855
4.69%, 12/15/44		196		229,381
4.67%, 06/06/47(a)		500		596,099
Boston Scientific Corp.:
3.85%, 05/15/25		382		410,428
4.00%, 03/01/29		250		276,684
4.55%, 03/01/39		1,000		1,176,419
4.70%, 03/01/49		800		973,546
DH Europe Finance II Sarl:
2.05%, 11/15/22		300		300,328
2.20%, 11/15/24		1,000		1,001,347
2.60%, 11/15/29(a)		445		443,386
3.25%, 11/15/39		400		403,452
3.40%, 11/15/49(a)		675		687,751
Medtronic Global Holdings SCA, 3.35%, 04/01/27(a)		250		266,713
Medtronic, Inc.:
3.15%, 03/15/22		1,350		1,388,500
3.63%, 03/15/24		400		424,225

Security	Par (000)		Value
Health Care Equipment & Supplies (continued)
3.50%, 03/15/25(a)	$	1,084	$	1,162,035
4.38%, 03/15/35		350		414,428
4.63%, 03/15/45(a)		1,750		2,204,221
Stryker Corp.:
3.38%, 11/01/25		580		614,847
3.50%, 03/15/26(a)		500		532,251
4.63%, 03/15/46(a)		1,250		1,505,927
Zimmer Biomet Holdings, Inc.:
3.15%, 04/01/22(a)		1,500		1,531,519
3.55%, 04/01/25(a)		750		790,957
4.45%, 08/15/45		500		538,048
				24,731,570
Health Care Providers & Services — 0.7%
Adventist Health System/West, 3.63%, 03/01/49		197		192,307
Advocate Health & Hospitals Corp.:
3.83%, 08/15/28		74		80,467
4.27%, 08/15/48		107		121,929
3.39%, 10/15/49		85		85,173
Aetna, Inc.:
2.75%, 11/15/22		2,250		2,286,665
2.80%, 06/15/23		1,500		1,524,379
3.50%, 11/15/24(a)		320		335,016
6.75%, 12/15/37(a)		300		404,994
4.50%, 05/15/42		250		269,680
4.75%, 03/15/44		25		27,927
3.88%, 08/15/47		1,400		1,424,109
Allina Health System, Series 2019, 3.89%, 04/15/49		220		233,982
Anthem, Inc.:
3.13%, 05/15/22(a)		1,200		1,230,170
2.95%, 12/01/22(a)		1,000		1,023,075
3.30%, 01/15/23		100		103,476
3.50%, 08/15/24		250		262,118
2.38%, 01/15/25		160		159,812
4.63%, 05/15/42		50		56,422
4.65%, 01/15/43(a)		2,000		2,256,602
5.10%, 01/15/44		900		1,077,109
4.65%, 08/15/44		350		396,743
4.38%, 12/01/47		1,000		1,104,122
Ascension Health:
3.95%, 11/15/46		1,000		1,110,629
Series B, 2.53%, 11/15/29		150		148,604
Series B, 3.11%, 11/15/39		52		51,083
Children’s Hospital Corp., Series 2017, 4.12%, 01/01/47		200		226,863
CHRISTUS Health, Series C, 4.34%, 07/01/28		155		171,244
Cigna Corp.:
4.75%, 11/15/21(b)		300		314,513
4.00%, 02/15/22(b)		1,525		1,574,595
3.05%, 11/30/22(b)		3,000		3,066,631
3.00%, 07/15/23(b)		1,000		1,021,842
3.75%, 07/15/23		2,000		2,097,591
3.50%, 06/15/24(b)		1,250		1,305,642
3.25%, 04/15/25(b)		300		311,134
4.13%, 11/15/25(a)		1,000		1,085,244
4.50%, 02/25/26(b)		250		274,345
3.40%, 03/01/27(b)		750		779,548
4.38%, 10/15/28		3,000		3,323,664
4.80%, 08/15/38(a)		1,000		1,166,420
4.80%, 07/15/46(a)(b)		250		290,186
3.88%, 10/15/47(b)		750		762,457
4.90%, 12/15/48(a)		1,500		1,791,744
CommonSpirit Health:
2.76%, 10/01/24		245		247,268

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Health Care Providers & Services (continued)
3.35%, 10/01/29	$	132	$	132,810
3.82%, 10/01/49		251		244,933
4.19%, 10/01/49		245		244,957
Dartmouth-Hitchcock Health, Series B, 4.18%, 08/01/48		100		111,568
Dignity Health, 5.27%, 11/01/64		100		115,185
Duke University Health System, Inc., Series 2017, 3.92%, 06/01/47(a)		173		193,204
HCA, Inc.:
4.75%, 05/01/23		3,000		3,213,944
5.25%, 04/15/25		1,000		1,118,910
4.13%, 06/15/29		750		795,809
5.13%, 06/15/39(a)		1,000		1,102,204
5.50%, 06/15/47		1,000		1,149,498
5.25%, 06/15/49(a)		500		558,964
Humana, Inc.:
3.85%, 10/01/24(a)		500		531,567
3.13%, 08/15/29		500		510,054
4.63%, 12/01/42		1,000		1,125,728
4.95%, 10/01/44(a)		250		295,342
4.80%, 03/15/47		200		234,424
Johns Hopkins Health System Corp., 3.84%, 05/15/46		25		27,220
Kaiser Foundation Hospitals:
3.50%, 04/01/22(a)		100		103,352
3.15%, 05/01/27		500		522,317
4.15%, 05/01/47		1,110		1,267,762
Series 2019, 3.27%, 11/01/49		325		326,199
Laboratory Corp. of America Holdings:
3.75%, 08/23/22(a)		100		103,859
4.00%, 11/01/23		100		105,845
3.25%, 09/01/24(a)		1,000		1,040,393
3.60%, 02/01/25		75		78,962
3.60%, 09/01/27(a)		500		528,321
4.70%, 02/01/45		450		506,697
Mayo Clinic, Series 2016, 4.13%, 11/15/52		300		344,393
McKesson Corp.:
2.85%, 03/15/23		150		152,358
3.80%, 03/15/24(a)		1,500		1,578,901
3.95%, 02/16/28(a)		1,000		1,066,909
Memorial Health Services, 3.45%, 11/01/49		175		172,139
Memorial Sloan-Kettering Cancer Center:
5.00%, 07/01/42		200		251,328
4.13%, 07/01/52(a)		200		228,430
Mercy Health, Series 2018, 4.30%, 07/01/28		64		71,701
Mount Sinai Hospitals Group, Inc.:
Series 2017, 3.98%, 07/01/48(a)		66		66,920
Series 2019, 3.74%, 07/01/49		300		299,113
New York and Presbyterian Hospital:
4.02%, 08/01/45		150		167,510
Series 2019, 3.95%, 08/01/19		207		208,945
Northwell Healthcare, Inc.:
3.98%, 11/01/46		200		204,906
4.26%, 11/01/47		70		75,304
3.81%, 11/01/49		162		163,096
Orlando Health Obligated Group, 4.09%, 10/01/48		29		31,861
Partners Healthcare System, Inc., Series 2017, 3.77%, 07/01/48		85		88,706
PeaceHealth Obligated Group, Series 2018, 4.79%, 11/15/48		79		97,270
Providence St Joseph Health Obligated Group:
Series 19A, 2.53%, 10/01/29		325		319,137
Series A, 3.93%, 10/01/48		77		83,397

Security	Par (000)		Value
Health Care Providers & Services (continued)
Quest Diagnostics, Inc.:
4.70%, 04/01/21	$	100	$	103,323
4.25%, 04/01/24		250		269,214
3.50%, 03/30/25		370		389,864
4.20%, 06/30/29(a)		250		276,191
RWJ Barnabas Health, Inc., 3.95%, 07/01/46		160		169,615
Spectrum Health System Obligated Group, Series 19A, 3.49%, 07/15/49		85		85,118
Stanford Health Care, Series 2018, 3.80%, 11/15/48		64		69,357
Sutter Health, :
3.70%, 08/15/28		86		92,167
4.09%, 08/15/48(a)		107		117,061
Toledo Hospital:
6.02%, 11/15/48		125		141,695
Series B, 5.33%, 11/15/28		125		135,344
Trinity Health Corp., Series 2019, 3.43%, 12/01/48		137		135,379
UnitedHealth Group, Inc.:
2.13%, 03/15/21		1,500		1,505,192
3.15%, 06/15/21		2,000		2,036,981
3.35%, 07/15/22		750		776,862
2.88%, 03/15/23		250		256,831
2.38%, 08/15/24		425		430,639
3.10%, 03/15/26(a)		500		523,745
3.45%, 01/15/27		500		536,140
3.38%, 04/15/27(a)		1,000		1,067,564
3.85%, 06/15/28(a)		1,000		1,103,493
2.88%, 08/15/29		1,890		1,945,357
4.63%, 07/15/35(a)		555		674,170
6.88%, 02/15/38		100		148,244
3.50%, 08/15/39(a)		645		677,372
5.95%, 02/15/41		100		135,782
3.95%, 10/15/42		150		165,161
4.75%, 07/15/45		2,500		3,078,604
4.20%, 01/15/47		750		861,117
4.25%, 04/15/47		1,000		1,157,793
3.75%, 10/15/47(a)		500		538,192
4.25%, 06/15/48		400		464,987
3.70%, 08/15/49(a)		1,500		1,612,305
Willis-Knighton Medical Center, Series 2018, 4.81%, 09/01/48		108		128,976
				79,549,711
Hotels, Restaurants & Leisure — 0.3%
GLP Capital LP/GLP Financing II, Inc.:
3.35%, 09/01/24		215		219,453
5.25%, 06/01/25		400		439,040
5.30%, 01/15/29		1,000		1,110,700
4.00%, 01/15/30(a)		980		1,000,286
Hyatt Hotels Corp.:
3.38%, 07/15/23(a)		190		194,668
4.38%, 09/15/28		305		331,163
Las Vegas Sands Corp.:
3.20%, 08/08/24		2,745		2,826,267
3.50%, 08/18/26		270		277,774
3.90%, 08/08/29		185		193,167
Marriott International, Inc.:
2.30%, 01/15/22		2,000		2,009,470
3.25%, 09/15/22		100		102,808
2.13%, 10/03/22		1,000		1,001,923
McDonald’s Corp.:
2.63%, 01/15/22(a)		3,000		3,043,198
3.35%, 04/01/23		250		260,401
3.25%, 06/10/24		400		421,077
3.38%, 05/26/25(a)		500		529,002

SCHEDULE OF INVESTMENTS 37

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Hotels, Restaurants & Leisure (continued)
3.70%, 01/30/26	$	250	$	269,761
3.50%, 03/01/27		1,000		1,068,367
3.80%, 04/01/28(a)		1,000		1,093,651
2.63%, 09/01/29		1,000		1,001,424
4.70%, 12/09/35		315		373,602
6.30%, 03/01/38(a)		1,000		1,354,625
3.70%, 02/15/42		100		101,567
4.88%, 12/09/45(a)		750		904,206
4.45%, 03/01/47		500		568,537
4.45%, 09/01/48		500		573,075
3.63%, 09/01/49		875		890,068
Regency Centers LP, 2.95%, 09/15/29		1,000		999,433
Sands China Ltd.:
4.60%, 08/08/23(a)		500		529,219
5.13%, 08/08/25		500		551,250
5.40%, 08/08/28		1,750		1,977,068
Starbucks Corp.:
2.70%, 06/15/22		500		508,901
3.10%, 03/01/23(a)		3,000		3,094,057
3.85%, 10/01/23		250		265,209
3.80%, 08/15/25(a)		2,000		2,155,189
4.00%, 11/15/28		500		557,453
3.55%, 08/15/29(a)		1,250		1,356,049
3.75%, 12/01/47		1,000		1,039,695
				35,192,803
Household Durables — 0.0%
DR Horton, Inc., 2.50%, 10/15/24(a)		425		425,498
Leggett & Platt, Inc., 3.80%, 11/15/24		200		207,818
Mohawk Industries, Inc., 3.85%, 02/01/23(a)		125		130,323
Whirlpool Corp.:
5.15%, 03/01/43(a)		200		215,741
4.50%, 06/01/46		250		259,257
				1,238,637
Household Products — 0.0%
Clorox Co.(a):
3.05%, 09/15/22		50		51,204
3.50%, 12/15/24		250		264,629
Kimberly-Clark Corp.:
2.65%, 03/01/25(a)		85		87,136
2.75%, 02/15/26(a)		500		515,031
5.30%, 03/01/41(a)		250		331,109
3.20%, 07/30/46(a)		210		212,023
3.90%, 05/04/47		750		841,361
				2,302,493
Industrial Conglomerates — 0.2%
3M Co.:
1.63%, 09/19/21		500		498,888
2.00%, 06/26/22		500		501,952
1.75%, 02/14/23		500		497,274
2.00%, 02/14/25		1,000		994,625
3.00%, 08/07/25(a)		250		262,877
2.88%, 10/15/27(a)		750		782,280
2.38%, 08/26/29(a)		985		971,909
3.13%, 09/19/46(a)		250		240,887
4.00%, 09/14/48(a)		1,000		1,104,126
3.25%, 08/26/49(a)		430		418,550
Crane Co., 4.45%, 12/15/23		125		133,733
Dover Corp.:
3.15%, 11/15/25		250		258,869
2.95%, 11/04/29		170		171,338
General Electric Co.:
5.30%, 02/11/21		1,000		1,031,729

Security	Par (000)		Value
Industrial Conglomerates (continued)
4.63%, 01/07/21	$	72	$	73,636
4.65%, 10/17/21		201		209,565
2.70%, 10/09/22(a)		1,000		1,013,829
3.10%, 01/09/23(a)		1,500		1,532,629
3.45%, 05/15/24		4,086		4,241,385
6.75%, 03/15/32		394		506,177
5.88%, 01/14/38		2,215		2,692,465
6.88%, 01/10/39		1,322		1,766,909
4.13%, 10/09/42		60		61,899
4.50%, 03/11/44		300		328,702
Ingersoll-Rand Global Holding Co. Ltd., 4.30%, 02/21/48(a)		500		540,838
Koninklijke Philips NV, 5.00%, 03/15/42(a)		250		300,620
				21,137,691
Insurance — 0.8%
Aflac, Inc.:
3.63%, 06/15/23		250		263,073
3.63%, 11/15/24		250		267,315
2.88%, 10/15/26(a)		750		771,487
4.75%, 01/15/49		1,000		1,218,302
Alleghany Corp., 4.95%, 06/27/22		550		585,454
Allstate Corp.:
3.15%, 06/15/23		250		259,647
3.28%, 12/15/26		750		792,404
4.50%, 06/15/43		150		178,392
4.20%, 12/15/46(a)		1,250		1,440,616
American Financial Group, Inc., 4.50%, 06/15/47(a)		750		811,707
American International Group, Inc.:
3.30%, 03/01/21		2,000		2,029,108
4.88%, 06/01/22		250		266,906
4.13%, 02/15/24		250		268,477
3.75%, 07/10/25(a)		750		802,760
3.90%, 04/01/26		1,000		1,074,148
3.88%, 01/15/35		500		530,915
4.70%, 07/10/35		500		579,578
4.50%, 07/16/44		250		288,382
4.80%, 07/10/45		2,000		2,400,359
4.75%, 04/01/48		1,000		1,205,818
Aon Corp.:
2.20%, 11/15/22		335		336,577
4.50%, 12/15/28		1,000		1,126,644
Aon PLC:
2.80%, 03/15/21(a)		250		252,676
3.50%, 06/14/24		1,000		1,048,823
3.88%, 12/15/25		600		645,819
4.60%, 06/14/44		250		289,794
Arch Capital Finance LLC, 4.01%, 12/15/26(a)		1,000		1,098,430
Arch Capital Group US, Inc., 5.14%, 11/01/43		125		155,104
Assured Guaranty US Holdings, Inc., 5.00%, 07/01/24		110		122,373
AXA Equitable Holdings, Inc.:
4.35%, 04/20/28		1,000		1,086,048
5.00%, 04/20/48		500		538,154
AXA SA, 8.60%, 12/15/30		550		799,067
Berkshire Hathaway Finance Corp.:
4.25%, 01/15/21(a)		250		256,310
3.00%, 05/15/22		750		770,552
4.40%, 05/15/42		100		117,662
4.30%, 05/15/43		250		289,062
4.20%, 08/15/48		750		887,982
4.25%, 01/15/49		1,000		1,186,475
Berkshire Hathaway, Inc.:
2.20%, 03/15/21		500		501,934

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Insurance (continued)
3.00%, 02/11/23(a)	$	1,000	$	1,032,976
2.75%, 03/15/23		1,500		1,538,136
3.13%, 03/15/26		1,400		1,475,614
4.50%, 02/11/43(a)		1,100		1,334,032
Brighthouse Financial, Inc., 3.70%, 06/22/27(a)		2,500		2,494,170
Chubb Corp.:
6.00%, 05/11/37		50		69,145
Series 1, 6.50%, 05/15/38		100		146,487
Chubb INA Holdings, Inc.:
2.88%, 11/03/22		1,000		1,026,071
3.35%, 05/15/24		500		526,854
3.35%, 05/03/26		795		845,504
4.15%, 03/13/43		150		174,079
CNA Financial Corp.:
5.75%, 08/15/21		100		105,707
4.50%, 03/01/26		350		386,058
First American Financial Corp., 4.60%, 11/15/24		200		214,046
Hartford Financial Services Group, Inc.:
2.80%, 08/19/29		500		505,847
6.10%, 10/01/41		100		137,157
3.60%, 08/19/49(a)		1,335		1,370,143
Lincoln National Corp.:
4.20%, 03/15/22		1,350		1,408,294
4.00%, 09/01/23		200		212,962
3.35%, 03/09/25		65		67,668
3.80%, 03/01/28		1,500		1,599,043
6.30%, 10/09/37		250		323,624
4.35%, 03/01/48		200		220,485
Loews Corp.:
2.63%, 05/15/23		250		254,763
3.75%, 04/01/26		500		537,136
Manulife Financial Corp.:
4.15%, 03/04/26		500		550,419
(5 year USD Swap + 1.65%), 4.06%, 02/24/32(c)		500		518,755
Markel Corp.:
3.35%, 09/17/29		475		486,633
4.30%, 11/01/47		750		783,844
4.15%, 09/17/50		500		515,395
Marsh & McLennan Cos., Inc.:
4.80%, 07/15/21		50		51,816
2.75%, 01/30/22		1,000		1,016,030
3.30%, 03/14/23		500		517,333
3.88%, 03/15/24		500		533,399
3.50%, 06/03/24		1,000		1,050,548
3.75%, 03/14/26		1,000		1,074,741
4.38%, 03/15/29		1,000		1,140,141
4.90%, 03/15/49		1,000		1,270,025
MetLife, Inc.:
3.00%, 03/01/25		650		676,321
6.38%, 06/15/34		500		715,269
5.88%, 02/06/41(a)		2,000		2,724,182
4.13%, 08/13/42		300		342,169
4.88%, 11/13/43(a)		250		310,017
4.05%, 03/01/45		250		290,243
4.60%, 05/13/46(a)		500		616,261
Old Republic International Corp., 4.88%, 10/01/24		250		274,170
Principal Financial Group, Inc.:
3.40%, 05/15/25		250		262,003
3.10%, 11/15/26(a)		1,000		1,035,511
3.70%, 05/15/29(a)		135		147,229
4.63%, 09/15/42		50		58,254
4.30%, 11/15/46		250		282,925

Security	Par (000)		Value
Insurance (continued)
Progressive Corp.:
3.75%, 08/23/21	$	1,050	$	1,083,066
2.45%, 01/15/27		500		502,114
4.35%, 04/25/44		100		117,046
3.70%, 01/26/45		200		214,098
4.13%, 04/15/47		500		581,927
4.20%, 03/15/48(a)		500		585,452
Prudential Financial, Inc.:
3.50%, 05/15/24		1,000		1,064,225
3.88%, 03/27/28(a)		951		1,042,915
(3 mo. LIBOR US + 3.04%), 5.20%, 03/15/44(a)(c)		350		373,349
4.60%, 05/15/44		250		295,231
(3 mo. LIBOR US + 2.67%), 5.70%, 09/15/48(c)		1,000		1,142,500
3.94%, 12/07/49		908		991,343
4.35%, 02/25/50		1,000		1,152,853
3.70%, 03/13/51		1,250		1,315,793
Reinsurance Group of America, Inc., 3.90%, 05/15/29(a)		475		506,839
Travelers Cos., Inc.:
6.75%, 06/20/36		250		361,996
4.60%, 08/01/43(a)		850		1,030,758
4.30%, 08/25/45		250		291,106
4.00%, 05/30/47		250		283,398
4.05%, 03/07/48(a)		2,000		2,281,847
Travelers Property Casualty Corp., 6.38%, 03/15/33		100		138,035
Trinity Acquisition PLC, 4.40%, 03/15/26		500		543,690
Unum Group:
4.00%, 06/15/29(a)		1,000		1,050,341
5.75%, 08/15/42(a)		250		282,557
4.50%, 12/15/49		250		244,156
Voya Financial, Inc.:
3.65%, 06/15/26		350		369,780
5.70%, 07/15/43(a)		500		626,312
Willis North America, Inc.:
4.50%, 09/15/28		1,500		1,654,167
3.88%, 09/15/49(a)		80		79,815
WR Berkley Corp., 4.63%, 03/15/22(a)		200		210,929
XLIT Ltd., 5.50%, 03/31/45(a)		250		318,026
				83,529,632
Interactive Media & Services — 0.1%
Alphabet, Inc.(a):
3.63%, 05/19/21		25		25,657
3.38%, 02/25/24		500		531,875
2.00%, 08/15/26		2,500		2,487,577
Baidu, Inc.(a):
4.13%, 06/30/25		1,000		1,065,937
4.88%, 11/14/28		2,000		2,256,621
Booking Holdings, Inc.:
2.75%, 03/15/23		500		510,904
3.60%, 06/01/26		2,500		2,668,908
eBay, Inc.:
2.88%, 08/01/21		1,000		1,012,013
3.80%, 03/09/22		640		661,626
2.60%, 07/15/22		50		50,292
3.60%, 06/05/27(a)		1,000		1,048,772
Equinix, Inc., 5.88%, 01/15/26		600		636,756
				12,956,938
Internet & Direct Marketing Retail — 0.2%
Alibaba Group Holding Ltd.:
3.13%, 11/28/21(a)		475		483,550
3.60%, 11/28/24(a)		2,500		2,627,000
3.40%, 12/06/27		1,000		1,042,520

SCHEDULE OF INVESTMENTS 39

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Internet & Direct Marketing Retail (continued)
4.50%, 11/28/34	$	250	$	283,750
4.00%, 12/06/37		1,000		1,063,250
4.20%, 12/06/47(a)		1,300		1,458,438
Amazon.com, Inc.:
2.40%, 02/22/23		1,500		1,526,676
2.80%, 08/22/24		1,500		1,552,453
3.15%, 08/22/27		2,750		2,914,401
4.80%, 12/05/34(a)		600		757,159
3.88%, 08/22/37		1,000		1,136,585
4.05%, 08/22/47		2,500		2,942,117
4.25%, 08/22/57		1,000		1,219,922
Expedia Group, Inc.:
4.50%, 08/15/24		250		266,898
3.80%, 02/15/28		750		767,157
3.25%, 02/15/30(b)		325		312,800
				20,354,676
IT Services — 0.3%
Broadridge Financial Solutions, Inc.:
3.40%, 06/27/26		270		282,271
2.90%, 12/01/29		500		499,542
DXC Technology Co., 4.75%, 04/15/27(a)		1,000		1,077,085
Fidelity National Information Services, Inc.:
3.50%, 04/15/23		25		26,028
3.00%, 08/15/26(a)		750		776,100
Series 10Y, 4.25%, 05/15/28		1,000		1,120,930
Fiserv, Inc.:
2.75%, 07/01/24		1,120		1,139,785
4.20%, 10/01/28(a)		2,000		2,218,493
3.50%, 07/01/29		1,645		1,729,024
4.40%, 07/01/49(a)		880		999,050
Global Payments, Inc.:
4.80%, 04/01/26(a)		500		556,557
3.20%, 08/15/29		250		254,802
4.15%, 08/15/49		355		379,810
IBM Credit LLC, 3.00%, 02/06/23(a)		500		514,684
International Business Machines Corp.:
2.25%, 02/19/21(a)		1,000		1,003,642
2.90%, 11/01/21		100		101,855
2.50%, 01/27/22		600		607,035
2.85%, 05/13/22		2,250		2,300,900
2.88%, 11/09/22		3,400		3,488,200
3.63%, 02/12/24		775		821,691
3.45%, 02/19/26		250		266,687
3.30%, 05/15/26		500		527,829
3.30%, 01/27/27		1,000		1,061,530
3.50%, 05/15/29		5,000		5,379,539
5.88%, 11/29/32		250		333,582
4.00%, 06/20/42(a)		850		939,187
4.70%, 02/19/46(a)		250		301,932
4.25%, 05/15/49		1,925		2,203,091
PayPal Holdings, Inc.:
2.40%, 10/01/24		1,170		1,181,539
2.85%, 10/01/29		1,335		1,347,401
Verisk Analytics, Inc.(a):
4.13%, 03/15/29		500		549,116
4.00%, 06/15/25		250		269,214
Western Union Co., 6.20%, 11/17/36		525		598,874
				34,857,005
Leisure Products — 0.0%
Hasbro, Inc.:
2.60%, 11/19/22		305		306,869
3.00%, 11/19/24		500		502,573

Security	Par (000)		Value
Leisure Products (continued)
3.55%, 11/19/26	$	300	$	302,108
3.50%, 09/15/27(a)		250		248,995
3.90%, 11/19/29		300		302,176
6.35%, 03/15/40		500		578,754
5.10%, 05/15/44		60		59,671
				2,301,146
Life Sciences Tools & Services — 0.1%
Agilent Technologies, Inc.:
3.88%, 07/15/23(a)		200		209,888
2.75%, 09/15/29		645		640,418
PerkinElmer, Inc., 3.30%, 09/15/29		1,000		1,021,513
Thermo Fisher Scientific, Inc.:
4.15%, 02/01/24(a)		250		267,911
3.65%, 12/15/25		500		534,561
3.20%, 08/15/27(a)		500		523,231
2.60%, 10/01/29		970		959,560
4.10%, 08/15/47		500		566,936
				4,724,018
Machinery — 0.2%
Caterpillar, Inc.:
3.90%, 05/27/21		50		51,367
3.40%, 05/15/24(a)		500		529,577
2.60%, 09/19/29(a)		70		70,703
5.20%, 05/27/41		600		778,208
3.80%, 08/15/42(a)		1,450		1,627,121
3.25%, 09/19/49		1,000		1,004,131
CNH Industrial NV, 4.50%, 08/15/23(a)		3,000		3,212,340
Cummins, Inc., 3.65%, 10/01/23(a)		250		264,362
Deere & Co.:
3.90%, 06/09/42(a)		550		618,950
2.88%, 09/07/49		385		366,301
Flowserve Corp., 3.50%, 09/15/22		100		102,012
Fortive Corp.:
2.35%, 06/15/21		1,000		1,004,255
3.15%, 06/15/26		500		511,691
Illinois Tool Works, Inc.:
2.65%, 11/15/26(a)		3,000		3,080,928
4.88%, 09/15/41		50		63,536
3.90%, 09/01/42		75		86,823
Ingersoll-Rand Luxembourg Finance SA:
3.55%, 11/01/24		500		524,783
4.65%, 11/01/44		30		33,924
4.50%, 03/21/49		500		562,395
Parker-Hannifin Corp.:
3.25%, 06/14/29(a)		2,000		2,089,512
4.20%, 11/21/34		250		276,817
4.10%, 03/01/47(a)		500		545,581
4.00%, 06/14/49		500		540,796
Stanley Black & Decker, Inc.:
2.90%, 11/01/22(a)		150		153,488
4.25%, 11/15/28		1,000		1,128,243
4.85%, 11/15/48(a)		250		307,571
Valmont Industries, Inc., 5.00%, 10/01/44(a)		1,000		1,023,113
Westinghouse Air Brake Technologies Corp.:
4.40%, 03/15/24		500		530,907
4.95%, 09/15/28		500		550,030
Xylem, Inc., 4.38%, 11/01/46		500		545,104
				22,184,569
Media — 1.0%
Bell Canada, Inc.:
4.46%, 04/01/48		310		359,525
4.30%, 07/29/49(a)		265		300,187

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Media (continued)
Charter Communications Operating LLC/Charter Communications Operating Capital:
4.46%, 07/23/22	$	1,000	$	1,051,169
4.50%, 02/01/24		4,000		4,304,918
4.91%, 07/23/25		1,930		2,125,272
3.75%, 02/15/28		1,000		1,037,312
5.05%, 03/30/29		1,750		1,985,650
6.38%, 10/23/35		250		314,662
5.38%, 04/01/38(a)		1,000		1,141,039
6.48%, 10/23/45		1,000		1,239,726
5.38%, 05/01/47(a)		500		560,953
5.75%, 04/01/48		1,000		1,167,924
5.13%, 07/01/49		1,000		1,088,351
4.80%, 03/01/50		1,400		1,476,306
6.83%, 10/23/55		250		327,406
Cintas Corp. No. 2:
4.30%, 06/01/21		25		25,813
2.90%, 04/01/22		250		255,033
3.70%, 04/01/27		500		542,450
Comcast Corp.:
3.45%, 10/01/21		3,000		3,088,131
2.75%, 03/01/23		750		766,253
3.00%, 02/01/24		1,500		1,554,768
3.60%, 03/01/24		250		265,038
3.70%, 04/15/24		1,000		1,066,594
3.38%, 08/15/25		500		530,714
3.95%, 10/15/25		2,000		2,182,825
3.15%, 03/01/26		750		786,301
2.35%, 01/15/27		1,850		1,848,472
3.30%, 02/01/27		1,000		1,059,432
3.15%, 02/15/28(a)		250		262,096
3.55%, 05/01/28(a)		1,000		1,076,280
4.15%, 10/15/28		1,720		1,937,312
2.65%, 02/01/30		945		949,048
4.25%, 10/15/30		1,000		1,143,862
4.25%, 01/15/33(a)		650		753,403
4.20%, 08/15/34		2,235		2,550,780
4.40%, 08/15/35(a)		250		293,257
3.20%, 07/15/36(a)		500		511,906
3.90%, 03/01/38(a)		500		553,993
4.60%, 10/15/38		3,000		3,576,801
3.25%, 11/01/39		1,000		1,015,869
4.65%, 07/15/42		1,150		1,382,777
4.75%, 03/01/44		250		304,266
4.60%, 08/15/45		500		601,160
3.40%, 07/15/46(a)		500		507,485
4.00%, 08/15/47		500		551,330
3.97%, 11/01/47		1,500		1,652,593
4.00%, 03/01/48(a)		500		555,082
4.70%, 10/15/48		2,500		3,086,915
4.00%, 11/01/49		1,255		1,391,719
3.45%, 02/01/50		800		820,151
4.05%, 11/01/52		694		777,536
4.95%, 10/15/58		1,000		1,303,221
Discovery Communications LLC:
4.38%, 06/15/21		50		51,643
2.95%, 03/20/23(a)		1,000		1,019,202
3.25%, 04/01/23		50		51,452
3.90%, 11/15/24(a)		250		265,647
3.45%, 03/15/25		1,000		1,038,845
4.90%, 03/11/26		330		368,335
3.95%, 03/20/28		1,220		1,302,377
5.00%, 09/20/37(a)		500		565,093
4.95%, 05/15/42		50		55,465

Security	Par (000)		Value
Media (continued)
4.88%, 04/01/43	$	150	$	164,130
5.20%, 09/20/47		1,445		1,684,433
Fox Corp.(b):
4.03%, 01/25/24		2,000		2,131,315
4.71%, 01/25/29		1,000		1,140,383
5.48%, 01/25/39		1,000		1,223,593
5.58%, 01/25/49		500		636,996
Grupo Televisa SAB:
4.63%, 01/30/26(a)		2,000		2,143,750
6.63%, 01/15/40		250		312,109
5.00%, 05/13/45		200		208,062
6.13%, 01/31/46(a)		250		301,406
5.25%, 05/24/49		500		538,750
Interpublic Group of Cos., Inc.:
3.75%, 10/01/21		1,000		1,027,852
4.20%, 04/15/24		250		269,179
NBCUniversal Media LLC:
4.38%, 04/01/21		600		618,818
2.88%, 01/15/23(a)		250		256,931
5.95%, 04/01/41		250		344,004
4.45%, 01/15/43		250		291,566
Omnicom Group, Inc/Omnicom Capital, Inc.:
3.63%, 05/01/22(a)		125		129,490
3.65%, 11/01/24		70		73,989
3.60%, 04/15/26(a)		500		526,837
RELX Capital, Inc., 3.50%, 03/16/23		300		311,518
TCI Communications, Inc., 7.88%, 02/15/26		250		325,582
TELUS Corp.:
4.60%, 11/16/48		200		236,392
4.30%, 06/15/49(a)		500		551,285
Thomson Reuters Corp.:
4.30%, 11/23/23		250		268,298
3.35%, 05/15/26(a)		140		144,256
5.65%, 11/23/43		1,500		1,775,556
Time Warner Cable LLC:
4.13%, 02/15/21		100		101,619
4.00%, 09/01/21		300		306,996
6.55%, 05/01/37(a)		650		797,384
6.75%, 06/15/39		2,050		2,590,174
5.88%, 11/15/40		250		286,943
5.50%, 09/01/41		250		279,277
4.50%, 09/15/42(a)		1,225		1,252,414
TWDC Enterprises 18 Corp.:
2.30%, 02/12/21		500		503,304
3.75%, 06/01/21		50		51,400
2.35%, 12/01/22		1,300		1,319,396
3.15%, 09/17/25		165		175,373
3.00%, 02/13/26		200		210,619
1.85%, 07/30/26		1,000		982,789
2.95%, 06/15/27(a)		750		791,340
4.13%, 06/01/44		500		590,363
3.00%, 07/30/46		75		74,186
Series E, 4.13%, 12/01/41		250		287,347
ViacomCBS, Inc.:
4.25%, 09/01/23(a)		1,250		1,331,343
3.70%, 08/15/24		1,000		1,058,233
3.50%, 01/15/25		500		523,255
4.00%, 01/15/26(a)		1,500		1,607,251
3.38%, 02/15/28		500		512,476
3.70%, 06/01/28(a)		500		524,344
6.88%, 04/30/36		250		334,760
4.85%, 07/01/42		325		363,716
4.38%, 03/15/43		1,070		1,134,479
5.85%, 09/01/43		100		125,291

SCHEDULE OF INVESTMENTS 41

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Media (continued)
5.25%, 04/01/44(a)	$	250	$	290,111
4.90%, 08/15/44		1,000		1,131,981
Walt Disney Co.:
4.50%, 02/15/21		1,100		1,133,604
1.65%, 09/01/22		230		229,435
3.00%, 09/15/22		150		154,522
1.75%, 08/30/24		500		496,206
3.70%, 09/15/24		500		535,171
3.70%, 10/15/25		830		898,549
3.38%, 11/15/26		1,500		1,617,917
2.00%, 09/01/29		500		485,249
6.20%, 12/15/34		350		491,573
6.40%, 12/15/35		764		1,085,902
6.65%, 11/15/37(a)		250		371,631
4.75%, 09/15/44		500		624,628
4.95%, 10/15/45		15		19,585
4.75%, 11/15/46		1,500		1,915,588
2.75%, 09/01/49		1,000		944,023
WPP Finance 2010:
3.63%, 09/07/22		1,500		1,552,430
3.75%, 09/19/24(a)		250		263,833
				114,723,615
Metal Fabricating — 0.0%
Timken Co., 4.50%, 12/15/28		500		538,919
Metals & Mining — 0.3%
ArcelorMittal SA:
3.60%, 07/16/24		1,000		1,025,455
6.13%, 06/01/25		1,000		1,148,988
4.25%, 07/16/29(a)		1,000		1,044,795
7.00%, 10/15/39		375		457,098
Barrick Gold Corp., 5.25%, 04/01/42		950		1,133,773
Barrick North America Finance LLC:
5.70%, 05/30/41		250		308,380
5.75%, 05/01/43		250		318,326
BHP Billiton Finance USA Ltd.:
2.88%, 02/24/22(a)		1,250		1,274,310
5.00%, 09/30/43		1,850		2,369,303
Newmont Goldcorp Corp.:
3.63%, 06/09/21		250		254,814
3.50%, 03/15/22(a)		1,950		2,001,614
3.70%, 03/15/23		500		522,846
2.80%, 10/01/29		80		79,261
4.88%, 03/15/42		1,300		1,522,209
Nucor Corp.:
3.95%, 05/01/28(a)		1,000		1,085,668
5.20%, 08/01/43		250		308,805
4.40%, 05/01/48		500		567,302
Precision Castparts Corp.:
2.50%, 01/15/23(a)		150		152,681
4.20%, 06/15/35		250		277,743
Reliance Steel & Aluminum Co., 4.50%, 04/15/23		25		26,426
Rio Tinto Finance USA Ltd.:
3.75%, 06/15/25		3,500		3,763,475
5.20%, 11/02/40(a)		350		457,452
Rio Tinto Finance USA PLC:
4.75%, 03/22/42		100		122,498
4.13%, 08/21/42		500		573,567
Southern Copper Corp.:
3.50%, 11/08/22		1,000		1,030,937
3.88%, 04/23/25(a)		2,750		2,888,359
6.75%, 04/16/40(a)		1,350		1,801,406
5.88%, 04/23/45		615		767,213

Security	Par (000)		Value
Metals & Mining (continued)
Steel Dynamics, Inc.:
2.80%, 12/15/24	$	30	$	30,192
5.00%, 12/15/26		1,100		1,169,882
3.45%, 04/15/30		90		91,069
Teck Resources Ltd., 5.40%, 02/01/43		2,000		2,114,726
Vale Overseas Ltd.:
6.25%, 08/10/26		2,000		2,340,000
6.88%, 11/10/39		1,250		1,628,125
				34,658,698
Multi-Utilities — 0.1%
CenterPoint Energy Resources Corp., 5.85%, 01/15/41		250		318,757
CenterPoint Energy, Inc.:
2.50%, 09/01/24		425		425,611
4.25%, 11/01/28(a)		2,000		2,171,875
2.95%, 03/01/30		1,000		985,979
3.70%, 09/01/49(a)		250		246,112
Dominion Energy Gas Holdings LLC:
3.60%, 12/15/24		250		262,521
Series A, 2.50%, 11/15/24		495		497,319
Series B, 3.00%, 11/15/29		1,000		996,633
Series C, 3.90%, 11/15/49		300		299,637
ONE Gas, Inc., 4.66%, 02/01/44(a)		250		297,396
San Diego Gas & Electric Co.:
3.60%, 09/01/23		250		261,429
4.30%, 04/01/42		100		107,578
4.15%, 05/15/48		1,000		1,100,494
Washington Gas Light Co., 3.65%, 09/15/49		500		503,109
				8,474,450
Multiline Retail — 0.1%
Kohl’s Corp., 5.55%, 07/17/45		100		101,983
Nordstrom, Inc.:
4.00%, 10/15/21		100		102,638
4.38%, 04/01/30		200		203,971
5.00%, 01/15/44(a)		500		490,139
O’Reilly Automotive, Inc.:
4.35%, 06/01/28		1,000		1,116,615
3.90%, 06/01/29		1,000		1,092,837
Target Corp.:
2.90%, 01/15/22		150		153,479
3.50%, 07/01/24		1,000		1,070,405
2.50%, 04/15/26(a)		250		256,288
3.38%, 04/15/29(a)		1,000		1,087,152
4.00%, 07/01/42(a)		350		400,375
3.63%, 04/15/46(a)		850		929,911
3.90%, 11/15/47(a)		500		574,938
				7,580,731
Office Supplies & Equipment — 0.0%
VMware, Inc., 2.95%, 08/21/22		2,000		2,037,917
Oil, Gas & Consumable Fuels — 2.5%
Apache Corp.:
3.25%, 04/15/22		756		770,347
4.38%, 10/15/28		2,000		2,091,977
4.25%, 01/15/30(a)		750		777,914
5.10%, 09/01/40		250		254,534
5.25%, 02/01/42		250		260,581
4.75%, 04/15/43		250		241,557
4.25%, 01/15/44		600		553,370
Boardwalk Pipelines LP:
3.38%, 02/01/23(a)		200		203,786
4.80%, 05/03/29		500		535,984

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
BP Capital Markets America, Inc.:
4.74%, 03/11/21	$	550	$	568,374
2.11%, 09/16/21		500		502,427
3.25%, 05/06/22		100		103,221
2.52%, 09/19/22		1,000		1,013,214
2.75%, 05/10/23		350		358,090
3.22%, 11/28/23(a)		1,000		1,041,953
3.41%, 02/11/26		2,000		2,131,000
3.12%, 05/04/26(a)		350		365,746
3.02%, 01/16/27		500		516,904
3.94%, 09/21/28(a)		500		552,660
4.23%, 11/06/28		1,000		1,131,053
BP Capital Markets PLC:
3.56%, 11/01/21		3,000		3,093,785
3.06%, 03/17/22		210		215,354
3.99%, 09/26/23		250		267,249
3.28%, 09/19/27		500		526,148
Canadian Natural Resources Ltd.:
3.45%, 11/15/21		1,100		1,127,455
2.95%, 01/15/23(a)		1,000		1,020,155
3.80%, 04/15/24		1,250		1,320,903
3.90%, 02/01/25		250		266,432
3.85%, 06/01/27		250		266,266
6.25%, 03/15/38(a)		300		390,394
4.95%, 06/01/47(a)		1,500		1,824,068
Cenovus Energy, Inc.:
4.25%, 04/15/27		1,000		1,059,468
5.25%, 06/15/37		500		554,193
6.75%, 11/15/39(a)		500		637,034
5.40%, 06/15/47(a)		500		581,132
Cheniere Corpus Christi Holdings LLC:
7.00%, 06/30/24		1,000		1,152,390
5.13%, 06/30/27		1,500		1,657,770
3.70%, 11/15/29(b)		500		510,609
Chevron Corp.:
2.10%, 05/16/21(a)		3,000		3,018,945
2.41%, 03/03/22		145		146,915
3.19%, 06/24/23		500		520,531
3.33%, 11/17/25(a)		500		534,422
2.95%, 05/16/26		1,250		1,306,583
Cimarex Energy Co., 4.38%, 03/15/29		1,000		1,060,790
CNOOC Finance 2013 Ltd., 3.00%, 05/09/23		1,300		1,320,719
CNOOC Finance 2015 USA LLC:
3.50%, 05/05/25		500		521,493
4.38%, 05/02/28		2,000		2,220,000
CNOOC Nexen Finance 2014 ULC:
4.25%, 04/30/24		1,750		1,873,594
4.88%, 04/30/44		500		610,938
Columbia Pipeline Group, Inc., 4.50%, 06/01/25(a)		250		274,313
Concho Resources, Inc.:
3.75%, 10/01/27(a)		1,000		1,051,842
4.88%, 10/01/47		500		584,161
ConocoPhillips, 6.50%, 02/01/39		1,400		2,040,311
ConocoPhillips Co.:
4.95%, 03/15/26(a)		1,000		1,150,802
4.30%, 11/15/44		500		586,994
5.95%, 03/15/46		750		1,073,563
ConocoPhillips Holding Co., 6.95%, 04/15/29		850		1,155,941
Continental Resources, Inc.:
4.38%, 01/15/28(a)		1,000		1,063,380
4.90%, 06/01/44		250		265,439
Devon Energy Corp.:
5.85%, 12/15/25(a)		250		296,465
5.60%, 07/15/41		500		608,057

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
4.75%, 05/15/42	$	350	$	392,667
5.00%, 06/15/45		500		580,337
Diamondback Energy, Inc., 3.50%, 12/01/29		1,000		1,017,600
Ecopetrol SA:
5.88%, 09/18/23		350		388,430
4.13%, 01/16/25		1,000		1,051,875
5.38%, 06/26/26		500		560,625
5.88%, 05/28/45		2,250		2,652,188
Enable Midstream Partners LP:
4.95%, 05/15/28(a)		1,000		1,012,965
5.00%, 05/15/44		500		458,967
Enbridge Energy Partners LP:
4.20%, 09/15/21		100		103,058
5.88%, 10/15/25(a)		1,500		1,749,695
7.38%, 10/15/45		800		1,195,175
Enbridge, Inc.:
3.50%, 06/10/24		65		67,786
2.50%, 01/15/25		250		251,346
4.25%, 12/01/26		1,000		1,101,721
3.70%, 07/15/27		1,000		1,059,245
3.13%, 11/15/29		250		253,108
4.50%, 06/10/44		250		275,670
4.00%, 11/15/49		250		262,668
Encana Corp.:
3.90%, 11/15/21(a)		1,250		1,280,182
7.20%, 11/01/31		1,000		1,223,527
7.38%, 11/01/31(a)		250		305,007
6.50%, 02/01/38		250		295,369
Energy Transfer Operating LP:
5.20%, 02/01/22		250		262,182
3.60%, 02/01/23		150		153,653
4.25%, 03/15/23		1,000		1,044,515
4.90%, 02/01/24(a)		250		268,302
4.75%, 01/15/26		1,000		1,082,961
4.20%, 04/15/27		1,000		1,047,352
4.90%, 03/15/35(a)		250		262,623
5.15%, 02/01/43		500		513,989
5.95%, 10/01/43		150		167,555
5.15%, 03/15/45(a)		2,000		2,105,677
6.13%, 12/15/45		250		289,931
5.30%, 04/15/47(a)		250		266,884
6.25%, 04/15/49		1,500		1,810,218
Series 30Y, 6.00%, 06/15/48(a)		1,000		1,166,837
Energy Transfer Partners LP/Regency Energy Finance Corp., 5.88%, 03/01/22		500		530,712
Enterprise Products Operating LLC:
2.80%, 02/15/21		500		504,772
3.90%, 02/15/24		125		132,647
3.75%, 02/15/25		790		841,957
3.70%, 02/15/26(a)		960		1,022,060
3.95%, 02/15/27(a)		3,000		3,238,835
3.13%, 07/31/29		2,655		2,732,005
5.95%, 02/01/41		150		193,587
4.45%, 02/15/43		325		357,683
4.85%, 03/15/44		200		231,417
5.10%, 02/15/45(a)		250		299,719
4.90%, 05/15/46(a)		1,100		1,290,188
4.25%, 02/15/48		1,000		1,074,388
4.80%, 02/01/49		1,000		1,174,752
4.20%, 01/31/50		620		665,527
(3 mo. LIBOR US + 2.57%), 5.38%, 02/15/78(c)		1,000		993,793
Series E, (3 mo. LIBOR US + 3.03%), 5.25%, 08/16/77(c)		750		758,985

SCHEDULE OF INVESTMENTS 43

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
EOG Resources, Inc.:
3.15%, 04/01/25	$	80	$	84,013
5.10%, 01/15/36		250		307,238
EQM Midstream Partners LP, 4.75%, 07/15/23		1,000		1,003,191
EQT Corp.(a):
4.88%, 11/15/21		1,050		1,084,070
3.00%, 10/01/22		1,000		982,809
EQT Midstream Partners LP, Series 10Y, 5.50%, 07/15/28		1,000		982,933
Equinor ASA:
2.75%, 11/10/21		500		508,799
2.65%, 01/15/24		1,500		1,538,312
3.70%, 03/01/24		250		266,373
3.25%, 11/10/24		500		526,911
5.10%, 08/17/40		1,100		1,402,832
4.25%, 11/23/41		300		347,702
3.25%, 11/18/49		1,000		1,008,314
Exxon Mobil Corp.:
2.22%, 03/01/21		750		754,427
2.40%, 03/06/22		500		505,449
1.90%, 08/16/22		270		271,490
2.73%, 03/01/23(a)		1,000		1,024,278
3.18%, 03/15/24		250		261,939
2.02%, 08/16/24(a)		500		501,810
2.71%, 03/06/25		1,250		1,292,361
3.04%, 03/01/26(a)		620		650,476
2.28%, 08/16/26		500		503,374
2.44%, 08/16/29(a)		500		504,869
3.00%, 08/16/39		500		501,333
4.11%, 03/01/46(a)		1,000		1,174,054
3.10%, 08/16/49		1,500		1,497,632
Hess Corp.:
4.30%, 04/01/27(a)		1,500		1,599,636
5.60%, 02/15/41(a)		550		644,118
5.80%, 04/01/47		1,000		1,224,738
Husky Energy, Inc.:
3.95%, 04/15/22		150		155,147
4.00%, 04/15/24(a)		500		527,618
6.80%, 09/15/37		500		651,317
Kinder Morgan Energy Partners LP:
4.30%, 05/01/24		500		534,402
3.50%, 03/01/21		750		759,575
5.80%, 03/01/21		250		260,256
5.00%, 10/01/21		200		208,479
3.95%, 09/01/22		225		234,514
3.45%, 02/15/23		500		515,047
4.15%, 02/01/24(a)		1,000		1,060,558
4.25%, 09/01/24(a)		155		166,015
5.80%, 03/15/35		1,000		1,210,723
6.50%, 02/01/37		100		124,736
6.95%, 01/15/38		1,250		1,656,097
5.00%, 08/15/42		75		81,814
5.00%, 03/01/43		250		274,197
5.50%, 03/01/44		250		291,122
5.40%, 09/01/44(a)		250		288,064
Kinder Morgan, Inc.:
3.15%, 01/15/23		1,500		1,534,070
4.30%, 06/01/25		410		444,844
4.30%, 03/01/28(a)		1,000		1,090,417
5.30%, 12/01/34(a)		250		294,530
5.55%, 06/01/45		1,250		1,487,606
5.05%, 02/15/46		750		841,644
5.20%, 03/01/48(a)		1,250		1,451,560

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
Magellan Midstream Partners LP:
3.20%, 03/15/25	$	500	$	511,448
4.25%, 09/15/46(a)		250		266,863
4.85%, 02/01/49(a)		750		870,895
3.95%, 03/01/50		175		179,992
Marathon Oil Corp.:
2.80%, 11/01/22(a)		400		406,732
3.85%, 06/01/25		250		264,774
4.40%, 07/15/27		1,000		1,087,609
6.60%, 10/01/37		250		318,974
5.20%, 06/01/45(a)		250		290,915
Marathon Petroleum Corp.:
5.13%, 03/01/21		150		155,309
3.63%, 09/15/24		115		120,801
3.80%, 04/01/28(a)		1,000		1,052,691
4.75%, 09/15/44		250		274,844
5.85%, 12/15/45(a)		250		287,097
4.50%, 04/01/48(a)		1,000		1,064,080
MPLX LP:
3.50%, 12/01/22(b)		1,000		1,029,604
3.38%, 03/15/23		2,000		2,053,999
4.50%, 07/15/23		250		265,705
4.88%, 12/01/24		250		271,798
4.88%, 06/01/25		250		273,110
4.13%, 03/01/27(a)		1,000		1,050,439
4.00%, 03/15/28(a)		1,000		1,035,773
4.50%, 04/15/38		750		763,180
5.20%, 12/01/47(b)		500		532,474
4.70%, 04/15/48(a)		1,750		1,783,142
5.50%, 02/15/49		200		227,217
Nexen, Inc.:
7.88%, 03/15/32		900		1,303,031
6.40%, 05/15/37		400		547,000
Noble Energy, Inc.:
3.85%, 01/15/28(a)		1,500		1,585,044
5.25%, 11/15/43		500		563,387
4.95%, 08/15/47		500		555,745
4.20%, 10/15/49		500		506,733
Occidental Petroleum Corp.:
2.70%, 08/15/22		110		111,143
6.95%, 07/01/24(a)		1,000		1,178,099
2.90%, 08/15/24		500		508,170
3.50%, 06/15/25		250		258,181
5.55%, 03/15/26		1,090		1,236,181
3.40%, 04/15/26(a)		390		399,643
3.00%, 02/15/27		2,250		2,254,287
3.50%, 08/15/29(a)		225		229,696
6.45%, 09/15/36		350		429,945
4.30%, 08/15/39		30		30,591
6.20%, 03/15/40		1,250		1,502,129
4.50%, 07/15/44		250		252,574
6.60%, 03/15/46		1,000		1,289,260
4.40%, 04/15/46		250		253,258
4.20%, 03/15/48		1,250		1,241,774
4.40%, 08/15/49(a)		500		516,282
Series 1, 4.10%, 02/01/21		50		50,870
ONEOK Partners LP(a):
3.38%, 10/01/22		500		514,597
4.90%, 03/15/25		250		275,356
6.13%, 02/01/41		300		361,241
ONEOK, Inc.:
2.75%, 09/01/24		430		434,085
4.55%, 07/15/28(a)		500		550,064
3.40%, 09/01/29		1,000		1,016,137

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
4.95%, 07/13/47(a)	$	1,000	$	1,102,842
4.45%, 09/01/49		1,000		1,037,275
Petroleos Mexicanos:
6.63%, 06/15/35		250		255,750
5.50%, 01/21/21		350		359,625
6.38%, 02/04/21		1,400		1,453,375
4.88%, 01/24/22		1,280		1,326,400
5.38%, 03/13/22		2,800		2,933,875
3.50%, 01/30/23		280		282,100
4.63%, 09/21/23(a)		1,050		1,097,250
4.88%, 01/18/24		250		263,250
4.50%, 01/23/26		2,000		1,987,800
6.88%, 08/04/26		500		549,000
6.50%, 03/13/27		1,750		1,854,081
5.35%, 02/12/28		1,250		1,237,500
6.50%, 01/23/29(a)		2,000		2,101,250
6.84%, 01/23/30(b)		3,000		3,209,700
6.50%, 06/02/41(a)		550		545,703
5.50%, 06/27/44		862		766,103
6.38%, 01/23/45		2,750		2,670,078
5.63%, 01/23/46		850		764,203
6.75%, 09/21/47		2,473		2,494,639
6.35%, 02/12/48		2,000		1,936,463
7.69%, 01/23/50(b)		2,900		3,177,559
Phillips 66:
4.30%, 04/01/22		1,000		1,049,745
4.65%, 11/15/34		1,355		1,592,558
5.88%, 05/01/42		100		135,119
4.88%, 11/15/44		1,250		1,508,058
Phillips 66 Partners LP:
2.45%, 12/15/24		255		255,218
3.15%, 12/15/29		370		368,706
4.90%, 10/01/46		500		568,114
Pioneer Natural Resources Co., 3.95%, 07/15/22		150		155,684
Plains All American Pipeline LP/PAA Finance Corp.:
3.65%, 06/01/22		500		513,001
2.85%, 01/31/23(a)		250		252,495
3.60%, 11/01/24		750		771,925
4.50%, 12/15/26		500		532,841
5.15%, 06/01/42		50		50,451
4.70%, 06/15/44		750		729,367
4.90%, 02/15/45		1,000		996,544
Sabine Pass Liquefaction LLC:
5.63%, 02/01/21		3,500		3,597,625
5.63%, 03/01/25		1,000		1,126,309
5.00%, 03/15/27		1,000		1,100,789
4.20%, 03/15/28		750		795,036
Shell International Finance BV:
1.88%, 05/10/21		250		250,293
1.75%, 09/12/21(a)		1,000		999,598
2.25%, 01/06/23		1,000		1,008,304
3.40%, 08/12/23		2,000		2,097,430
2.00%, 11/07/24		1,000		997,367
3.25%, 05/11/25		1,250		1,324,968
2.88%, 05/10/26		500		518,850
2.50%, 09/12/26		1,000		1,016,730
2.38%, 11/07/29		1,000		991,899
4.13%, 05/11/35(a)		500		585,053
6.38%, 12/15/38		300		437,876
5.50%, 03/25/40(a)		300		405,211
4.55%, 08/12/43		200		243,905
4.38%, 05/11/45		2,500		2,984,546
4.00%, 05/10/46		1,250		1,424,508

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
3.75%, 09/12/46(a)	$	900	$	989,755
3.13%, 11/07/49		940		928,525
Spectra Energy Partners LP:
4.75%, 03/15/24		250		272,233
3.50%, 03/15/25		250		261,685
3.38%, 10/15/26		1,000		1,035,439
Suncor Energy, Inc.:
3.60%, 12/01/24(a)		1,165		1,236,469
6.50%, 06/15/38		500		696,035
6.85%, 06/01/39		250		360,738
4.00%, 11/15/47		1,500		1,637,358
Sunoco Logistics Partners Operations LP:
4.25%, 04/01/24(a)		400		420,676
4.00%, 10/01/27(a)		1,750		1,810,633
4.95%, 01/15/43		250		247,612
5.30%, 04/01/44		100		106,432
5.35%, 05/15/45		250		268,861
5.40%, 10/01/47(a)		500		543,639
TC PipeLines LP:
4.38%, 03/13/25		250		266,244
3.90%, 05/25/27		105		109,792
Total Capital Canada Ltd., 2.75%, 07/15/23		1,150		1,179,672
Total Capital International SA:
2.75%, 06/19/21		250		253,375
2.70%, 01/25/23		500		510,945
3.75%, 04/10/24(a)		1,000		1,071,115
3.46%, 02/19/29		3,000		3,252,663
3.46%, 07/12/49		500		526,079
Total Capital SA, 4.25%, 12/15/21		250		261,310
TransCanada PipeLines Ltd.:
2.50%, 08/01/22(a)		1,000		1,010,697
3.75%, 10/16/23		500		526,928
4.88%, 01/15/26		850		951,702
4.25%, 05/15/28(a)		750		833,097
4.63%, 03/01/34		2,250		2,566,528
6.20%, 10/15/37		200		260,985
4.75%, 05/15/38		250		285,620
7.25%, 08/15/38		250		361,489
7.63%, 01/15/39(a)		250		375,144
5.00%, 10/16/43		150		173,927
4.88%, 05/15/48(a)		750		887,170
5.10%, 03/15/49(a)		500		610,252
Transcanada Trust(3 mo. LIBOR US + 4.15%), 5.50%, 09/15/79(c)		250		262,375
Transcontinental Gas Pipe Line Co. LLC:
7.85%, 02/01/26		250		317,740
4.00%, 03/15/28		750		797,980
4.45%, 08/01/42(a)		250		263,384
Valero Energy Corp.:
3.65%, 03/15/25(a)		1,500		1,595,672
3.40%, 09/15/26(a)		750		786,168
4.00%, 04/01/29(a)		1,000		1,078,866
6.63%, 06/15/37(a)		300		396,952
4.90%, 03/15/45		500		576,756
Western Midstream Operating LP:
4.00%, 07/01/22		250		256,266
3.95%, 06/01/25		750		757,457
4.65%, 07/01/26(a)		250		256,002
4.50%, 03/01/28		1,000		987,286
4.75%, 08/15/28		1,000		1,009,021
Williams Cos., Inc.:
4.00%, 11/15/21		250		257,034
3.60%, 03/15/22		750		771,190

SCHEDULE OF INVESTMENTS 45

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
3.70%, 01/15/23	$	3,000	$	3,107,277
4.30%, 03/04/24		250		266,822
3.90%, 01/15/25		250		263,282
4.00%, 09/15/25		250		265,261
3.75%, 06/15/27(a)		750		782,295
6.30%, 04/15/40		250		310,177
5.75%, 06/24/44		1,000		1,185,145
4.90%, 01/15/45		500		539,865
5.10%, 09/15/45(a)		900		1,003,604
4.85%, 03/01/48(a)		500		547,391
				283,774,449
Paper & Forest Products — 0.1%
Fibria Overseas Finance, Ltd., 5.50%, 01/17/27(a)		1,000		1,095,625
Georgia-Pacific LLC, 8.88%, 05/15/31		525		816,009
International Paper Co.:
3.65%, 06/15/24		500		525,083
5.00%, 09/15/35		250		294,216
7.30%, 11/15/39		250		346,374
4.80%, 06/15/44		250		274,760
5.15%, 05/15/46		1,000		1,150,759
4.40%, 08/15/47		500		535,526
4.35%, 08/15/48(a)		750		798,559
WestRock MWV LLC, 8.20%, 01/15/30		100		137,962
				5,974,873
Personal Products — 0.1%
Colgate-Palmolive Co.:
3.25%, 03/15/24(a)		250		264,060
3.70%, 08/01/47		750		862,237
Estee Lauder Cos., Inc.:
2.00%, 12/01/24		325		325,872
3.15%, 03/15/27(a)		1,000		1,056,239
2.38%, 12/01/29		130		129,964
4.15%, 03/15/47(a)		250		291,154
3.13%, 12/01/49		185		185,134
Procter & Gamble Co.:
2.30%, 02/06/22		250		253,386
3.10%, 08/15/23		500		522,341
2.85%, 08/11/27(a)		500		530,198
3.50%, 10/25/47(a)		1,000		1,128,440
Unilever Capital Corp.:
4.25%, 02/10/21(a)		200		205,364
1.38%, 07/28/21		3,000		2,981,555
3.13%, 03/22/23(a)		2,000		2,067,836
3.10%, 07/30/25(a)		250		261,919
2.00%, 07/28/26(a)		750		743,381
2.13%, 09/06/29		1,000		971,272
				12,780,352
Pharmaceuticals — 1.6%
Abbott Laboratories:
2.55%, 03/15/22		1,000		1,016,403
3.88%, 09/15/25		45		49,018
3.75%, 11/30/26(a)		1,417		1,548,287
4.75%, 11/30/36		2,500		3,135,370
5.30%, 05/27/40		500		657,442
4.75%, 04/15/43(a)		250		314,919
4.90%, 11/30/46(a)		1,000		1,314,259
AbbVie, Inc.:
2.30%, 05/14/21		750		752,763
2.15%, 11/19/21(b)		700		701,014
2.90%, 11/06/22		1,250		1,275,773
2.30%, 11/21/22(b)		1,400		1,407,076
2.85%, 05/14/23(a)		1,500		1,529,943

Security	Par (000)		Value
Pharmaceuticals (continued)
3.75%, 11/14/23	$	3,000	$	3,157,864
2.60%, 11/21/24(b)		1,850		1,864,970
3.60%, 05/14/25(a)		1,500		1,584,712
3.20%, 05/14/26(a)		1,435		1,487,078
2.95%, 11/21/26(b)		2,000		2,036,328
3.20%, 11/21/29(b)		2,600		2,645,122
4.50%, 05/14/35(a)		450		507,533
4.30%, 05/14/36		200		220,165
4.05%, 11/21/39(b)		1,895		1,991,753
4.40%, 11/06/42		1,400		1,504,782
4.70%, 05/14/45		1,000		1,117,469
4.45%, 05/14/46(a)		1,250		1,338,859
4.88%, 11/14/48		1,000		1,155,336
4.25%, 11/21/49(a)(b)		3,445		3,657,965
Allergan Finance LLC, 3.25%, 10/01/22		3,150		3,219,769
Allergan Funding SCS:
3.45%, 03/15/22		1,155		1,181,524
3.80%, 03/15/25		750		788,181
4.55%, 03/15/35(a)		630		688,727
4.85%, 06/15/44(a)		1,250		1,362,352
4.75%, 03/15/45		668		727,528
AmerisourceBergen Corp.:
3.45%, 12/15/27		750		783,888
4.25%, 03/01/45		250		257,129
4.30%, 12/15/47		500		519,324
AstraZeneca PLC:
2.38%, 06/12/22		500		505,799
3.38%, 11/16/25(a)		1,700		1,806,849
3.13%, 06/12/27(a)		500		521,546
4.00%, 01/17/29		1,500		1,666,309
6.45%, 09/15/37		100		141,047
4.38%, 11/16/45(a)		950		1,107,903
4.38%, 08/17/48(a)		1,150		1,343,966
Bristol-Myers Squibb Co.:
2.00%, 08/01/22(a)		250		251,644
3.25%, 08/15/22(b)		150		154,999
3.55%, 08/15/22(b)		750		779,478
4.00%, 08/15/23(b)		750		799,182
3.88%, 08/15/25(b)		500		540,512
3.20%, 06/15/26(b)		5,000		5,253,095
3.45%, 11/15/27(b)		1,000		1,070,272
3.90%, 02/20/28(b)		1,000		1,102,381
3.40%, 07/26/29(a)(b)		1,500		1,605,335
5.25%, 08/15/43(b)		145		188,161
4.50%, 03/01/44(a)		250		301,060
5.00%, 08/15/45(b)		750		962,093
4.35%, 11/15/47(b)		500		596,656
4.55%, 02/20/48(b)		1,000		1,225,316
4.25%, 10/26/49(a)(b)		2,500		2,968,188
Cardinal Health, Inc.:
2.62%, 06/15/22		1,000		1,010,240
3.50%, 11/15/24		250		261,201
3.41%, 06/15/27		2,000		2,045,784
4.60%, 03/15/43		50		50,186
4.90%, 09/15/45		250		260,880
4.37%, 06/15/47		500		496,795
CVS Health Corp.:
3.35%, 03/09/21		797		810,251
2.13%, 06/01/21(a)		250		250,432
3.50%, 07/20/22		500		516,216
3.70%, 03/09/23		4,000		4,169,344
4.00%, 12/05/23		500		529,152
2.63%, 08/15/24(a)		1,225		1,235,450
4.10%, 03/25/25(a)		1,500		1,610,496

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Pharmaceuticals (continued)
3.88%, 07/20/25	$	943	$	1,004,395
2.88%, 06/01/26(a)		750		760,999
4.30%, 03/25/28		4,500		4,915,986
4.88%, 07/20/35(a)		1,000		1,150,209
4.78%, 03/25/38(a)		2,500		2,842,173
5.13%, 07/20/45(a)		1,250		1,482,894
5.05%, 03/25/48		4,750		5,628,875
Eli Lilly & Co.:
2.75%, 06/01/25		45		46,413
3.10%, 05/15/27(a)		750		786,283
3.38%, 03/15/29		1,000		1,077,118
3.95%, 03/15/49		1,000		1,158,377
4.15%, 03/15/59		500		590,572
GlaxoSmithKline Capital PLC:
2.85%, 05/08/22		3,650		3,730,441
2.88%, 06/01/22		500		510,913
3.38%, 06/01/29(a)		1,000		1,073,349
GlaxoSmithKline Capital, Inc.:
2.80%, 03/18/23(a)		1,500		1,537,246
3.38%, 05/15/23		1,000		1,042,985
3.63%, 05/15/25(a)		1,500		1,610,531
3.88%, 05/15/28		1,000		1,104,590
5.38%, 04/15/34		250		321,943
6.38%, 05/15/38(a)		1,100		1,579,549
Johnson & Johnson:
1.65%, 03/01/21		500		499,806
2.45%, 12/05/21		450		455,108
2.25%, 03/03/22		250		252,763
2.05%, 03/01/23		750		754,585
2.45%, 03/01/26(a)		370		375,763
4.38%, 12/05/33		250		296,191
3.55%, 03/01/36(a)		750		820,807
3.63%, 03/03/37		500		552,330
4.50%, 09/01/40		100		122,156
4.50%, 12/05/43		750		929,658
3.70%, 03/01/46		500		565,193
3.75%, 03/03/47(a)		2,000		2,287,371
3.50%, 01/15/48(a)		750		821,956
Mead Johnson Nutrition Co., 4.60%, 06/01/44(a)		250		299,431
Merck & Co., Inc.:
3.88%, 01/15/21		250		254,715
2.35%, 02/10/22		1,500		1,514,989
2.75%, 02/10/25		3,570		3,704,248
3.90%, 03/07/39(a)		500		572,010
4.15%, 05/18/43(a)		250		298,297
3.70%, 02/10/45		1,900		2,101,923
4.00%, 03/07/49		1,000		1,172,896
Mylan NV:
3.15%, 06/15/21		1,000		1,013,143
3.95%, 06/15/26		250		260,631
5.25%, 06/15/46		500		562,380
Mylan, Inc.:
4.20%, 11/29/23(a)		250		264,725
4.55%, 04/15/28(a)		800		861,254
5.20%, 04/15/48		550		615,801
Novartis Capital Corp.:
3.40%, 05/06/24		650		688,383
3.00%, 11/20/25		1,100		1,156,402
3.10%, 05/17/27(a)		2,500		2,647,307
4.40%, 05/06/44		1,250		1,523,714
Perrigo Finance Unlimited Co.:
3.90%, 12/15/24		250		256,966
4.38%, 03/15/26		250		258,102

Security	Par (000)		Value
Pharmaceuticals (continued)
Pfizer, Inc.:
1.95%, 06/03/21	$	500	$	502,323
2.20%, 12/15/21		3,000		3,029,401
5.80%, 08/12/23		500		565,111
3.40%, 05/15/24(a)		1,000		1,058,070
2.75%, 06/03/26		115		118,982
3.00%, 12/15/26(a)		1,750		1,839,407
3.45%, 03/15/29(a)		1,000		1,077,680
4.00%, 12/15/36		500		567,075
3.90%, 03/15/39		500		564,105
7.20%, 03/15/39(a)		2,250		3,539,533
4.30%, 06/15/43		500		587,204
4.40%, 05/15/44		500		597,150
4.13%, 12/15/46		500		581,404
4.20%, 09/15/48		500		586,708
4.00%, 03/15/49(a)		500		575,590
Quest Diagnostics, Inc., 2.95%, 06/30/30		425		425,082
Sanofi, 3.63%, 06/19/28(a)		2,000		2,203,363
Shire Acquisitions Investments Ireland DAC:
2.88%, 09/23/23		500		509,509
3.20%, 09/23/26		900		927,535
Takeda Pharmaceutical Co. Ltd.:
4.00%, 11/26/21		3,000		3,102,449
4.40%, 11/26/23		1,000		1,073,921
5.00%, 11/26/28(a)		1,000		1,165,091
Wyeth LLC:
6.50%, 02/01/34		500		703,789
5.95%, 04/01/37		250		341,496
Zoetis, Inc.:
3.25%, 02/01/23(a)		1,000		1,029,504
3.90%, 08/20/28		1,000		1,085,139
4.70%, 02/01/43(a)		400		477,009
4.45%, 08/20/48(a)		250		290,880
				177,480,198
Professional Services — 0.0%
IHS Markit Ltd.:
4.75%, 08/01/28		300		334,129
4.25%, 05/01/29		1,000		1,077,620
				1,411,749
Real Estate — 0.1%
CBRE Services, Inc.(a):
5.25%, 03/15/25		250		281,369
4.88%, 03/01/26		250		278,743
Equifax, Inc.:
2.60%, 12/01/24		1,000		1,006,286
3.25%, 06/01/26(a)		250		251,259
Equinix, Inc.:
2.63%, 11/18/24		335		335,623
2.90%, 11/18/26		135		135,236
5.38%, 05/15/27		1,100		1,194,633
3.20%, 11/18/29		455		456,693
Highwoods Realty LP:
4.13%, 03/15/28		250		267,744
3.05%, 02/15/30		500		493,148
Prologis LP:
3.75%, 11/01/25		45		48,722
4.38%, 09/15/48		100		120,446
Vornado Realty LP, 3.50%, 01/15/25(a)		250		260,115
				5,130,017
Road & Rail — 0.4%
Burlington Northern Santa Fe LLC:
3.45%, 09/15/21		2,000		2,045,590
3.75%, 04/01/24		50		53,332

SCHEDULE OF INVESTMENTS 47

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Road & Rail (continued)
3.65%, 09/01/25	$	750	$	808,419
7.00%, 12/15/25		250		316,052
3.25%, 06/15/27		1,750		1,868,200
5.40%, 06/01/41		50		64,698
4.40%, 03/15/42		150		173,814
4.38%, 09/01/42		250		290,619
4.45%, 03/15/43		200		235,000
5.15%, 09/01/43(a)		250		319,155
4.90%, 04/01/44		500		623,529
4.55%, 09/01/44		250		298,139
4.15%, 04/01/45		500		567,700
3.90%, 08/01/46(a)		2,000		2,196,873
4.13%, 06/15/47		250		284,101
4.05%, 06/15/48		1,000		1,134,147
4.15%, 12/15/48(a)		500		576,173
3.55%, 02/15/50		125		131,721
Canadian National Railway Co.:
2.85%, 12/15/21(a)		1,000		1,014,666
2.95%, 11/21/24		305		315,010
2.75%, 03/01/26		560		573,732
3.50%, 11/15/42		100		104,424
3.65%, 02/03/48		1,500		1,656,244
Canadian Pacific Railway Co.:
4.45%, 03/15/23		500		532,062
2.90%, 02/01/25		1,000		1,027,133
7.13%, 10/15/31		250		346,815
4.80%, 09/15/35		250		297,837
5.75%, 01/15/42		25		33,215
4.80%, 08/01/45(a)		1,110		1,377,573
CSX Corp.:
3.35%, 11/01/25(a)		250		264,910
3.80%, 03/01/28(a)		3,500		3,819,803
2.40%, 02/15/30		500		489,231
4.75%, 05/30/42		100		117,893
4.30%, 03/01/48(a)		750		852,058
4.50%, 03/15/49		1,000		1,172,041
3.35%, 09/15/49(a)		215		212,065
3.95%, 05/01/50(a)		450		486,477
4.50%, 08/01/54		250		288,210
4.25%, 11/01/66		750		802,358
Kansas City Southern:
3.13%, 06/01/26		250		255,256
2.88%, 11/15/29		120		119,719
4.70%, 05/01/48		500		586,552
4.20%, 11/15/69		105		107,357
Norfolk Southern Corp.:
3.00%, 04/01/22		1,750		1,786,432
3.85%, 01/15/24		1,000		1,061,324
3.15%, 06/01/27		880		919,935
2.55%, 11/01/29		165		164,578
3.95%, 10/01/42		100		106,777
4.45%, 06/15/45(a)		250		288,575
3.94%, 11/01/47		225		242,507
4.15%, 02/28/48		250		282,646
4.10%, 05/15/49		1,000		1,105,224
3.40%, 11/01/49		335		332,826
4.05%, 08/15/52		1,000		1,100,928
Ryder System, Inc.:
3.40%, 03/01/23(a)		500		515,699
2.50%, 09/01/24		285		286,345
2.90%, 12/01/26		1,160		1,167,949
Union Pacific Corp.:
4.16%, 07/15/22		100		105,102
3.65%, 02/15/24(a)		1,000		1,057,514

Security	Par (000)		Value
Road & Rail (continued)
3.25%, 08/15/25(a)	$	250	$	263,581
2.75%, 03/01/26		1,000		1,024,900
3.95%, 09/10/28		1,000		1,105,011
3.60%, 09/15/37		1,250		1,304,154
4.38%, 09/10/38		2,750		3,153,077
4.30%, 06/15/42		50		56,190
4.05%, 11/15/45		250		272,141
4.05%, 03/01/46		140		152,633
4.50%, 09/10/48(a)		500		590,622
3.80%, 10/01/51		250		265,596
3.95%, 08/15/59(a)		780		818,007
3.84%, 03/20/60(b)		450		456,581
				48,826,757
Semiconductors & Semiconductor Equipment — 0.4%
Altera Corp., 4.10%, 11/15/23(a)		250		269,466
Analog Devices, Inc.:
2.95%, 01/12/21		1,000		1,008,364
2.88%, 06/01/23		1,000		1,019,038
3.50%, 12/05/26(a)		750		786,928
Applied Materials, Inc.:
4.30%, 06/15/21		500		517,412
3.90%, 10/01/25(a)		160		174,440
3.30%, 04/01/27		1,000		1,060,542
5.85%, 06/15/41		300		407,616
4.35%, 04/01/47		500		604,259
Broadcom Corp./Broadcom Cayman Finance Ltd.:
3.00%, 01/15/22		1,500		1,522,191
2.65%, 01/15/23(a)		1,500		1,508,546
3.63%, 01/15/24(a)		250		259,106
3.88%, 01/15/27		3,750		3,895,342
3.50%, 01/15/28		500		503,144
Broadcom, Inc.(b):
3.13%, 10/15/22(a)		1,000		1,018,797
3.63%, 10/15/24		2,000		2,079,778
4.25%, 04/15/26		1,000		1,062,172
4.75%, 04/15/29		1,000		1,093,483
Intel Corp.:
1.70%, 05/19/21		1,000		999,410
2.70%, 12/15/22		2,500		2,562,001
2.88%, 05/11/24		1,000		1,038,740
3.70%, 07/29/25		1,000		1,081,717
2.45%, 11/15/29		500		498,637
4.10%, 05/19/46		2,500		2,886,292
4.10%, 05/11/47		250		290,520
3.73%, 12/08/47		1,399		1,540,265
KLA Corp.:
4.65%, 11/01/24		305		334,784
4.10%, 03/15/29		1,000		1,095,656
Lam Research Corp.:
3.80%, 03/15/25(a)		230		245,574
4.88%, 03/15/49		1,000		1,252,305
Maxim Integrated Products, Inc., 3.38%, 03/15/23(a)		100		102,293
Microchip Technology, Inc., 4.33%, 06/01/23		2,000		2,112,898
Micron Technology, Inc.:
4.64%, 02/06/24		300		325,588
4.98%, 02/06/26(a)		250		277,580
5.33%, 02/06/29		250		286,797
4.66%, 02/15/30		750		826,345
NVIDIA Corp.:
2.20%, 09/16/21		300		301,512
3.20%, 09/16/26		1,000		1,050,157
NXP BV/NXP Funding LLC/NXP USA, Inc.(b):
3.88%, 06/18/26		320		339,465
4.30%, 06/18/29		1,000		1,081,384

48 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Semiconductors & Semiconductor Equipment (continued)
QUALCOMM, Inc.:
3.00%, 05/20/22	$	1,500	$	1,537,906
2.60%, 01/30/23(a)		1,140		1,160,462
3.45%, 05/20/25(a)		250		264,422
3.25%, 05/20/27		500		526,275
4.65%, 05/20/35		250		297,218
4.80%, 05/20/45(a)		750		918,965
4.30%, 05/20/47		1,500		1,720,916
Seagate HDD Cayman:
4.75%, 06/01/23		168		178,637
4.88%, 06/01/27		500		531,369
5.75%, 12/01/34		650		680,998
Texas Instruments, Inc.:
2.25%, 09/04/29		680		671,438
4.15%, 05/15/48		1,000		1,189,299
Xilinx, Inc., 3.00%, 03/15/21		75		75,952
				49,074,401
Software — 0.6%
Activision Blizzard, Inc., 3.40%, 06/15/27		1,000		1,043,843
Autodesk, Inc., 3.50%, 06/15/27(a)		2,000		2,096,945
CA, Inc., 4.50%, 08/15/23		170		178,762
Microsoft Corp.:
1.55%, 08/08/21		1,000		998,677
2.40%, 02/06/22		1,000		1,014,136
2.38%, 02/12/22		1,000		1,013,608
2.65%, 11/03/22		500		512,078
2.00%, 08/08/23(a)		2,000		2,014,289
3.63%, 12/15/23		1,000		1,064,589
2.88%, 02/06/24		865		897,576
3.13%, 11/03/25		500		528,554
2.40%, 08/08/26		1,485		1,502,590
3.30%, 02/06/27		5,500		5,878,987
3.50%, 02/12/35		1,165		1,283,684
4.20%, 11/03/35		250		297,440
3.45%, 08/08/36		750		822,010
4.10%, 02/06/37(a)		1,250		1,478,756
4.50%, 10/01/40		500		620,016
5.30%, 02/08/41		100		136,735
3.75%, 05/01/43		150		168,574
3.75%, 02/12/45		500		568,619
4.45%, 11/03/45		1,500		1,878,293
3.70%, 08/08/46		2,500		2,826,884
4.00%, 02/12/55		1,750		2,075,088
4.75%, 11/03/55(a)		250		334,006
3.95%, 08/08/56		250		296,290
4.50%, 02/06/57(a)		1,500		1,945,662
Series 30Y, 4.25%, 02/06/47		1,500		1,840,590
Oracle Corp.:
2.80%, 07/08/21		1,000		1,015,288
1.90%, 09/15/21		2,000		2,004,190
2.50%, 10/15/22		3,250		3,310,295
2.63%, 02/15/23(a)		2,000		2,042,503
2.40%, 09/15/23(a)		1,000		1,016,700
2.95%, 11/15/24		500		519,754
2.95%, 05/15/25		500		520,525
2.65%, 07/15/26		745		762,124
3.25%, 11/15/27		2,750		2,914,655
3.25%, 05/15/30(a)		950		1,012,958
4.30%, 07/08/34(a)		250		292,494
3.90%, 05/15/35		500		557,686
3.85%, 07/15/36		750		822,349
3.80%, 11/15/37		750		819,718
6.13%, 07/08/39		500		705,344

Security	Par (000)		Value
Software (continued)
5.38%, 07/15/40(a)	$	400	$	519,937
4.50%, 07/08/44		500		594,418
4.13%, 05/15/45		2,250		2,542,517
4.00%, 07/15/46		1,250		1,391,458
4.00%, 11/15/47(a)		1,500		1,678,154
4.38%, 05/15/55		250		296,856
salesforce.com, Inc., 3.25%, 04/11/23(a)		2,500		2,600,562
				63,257,766
Specialty Retail — 0.3%
Advance Auto Parts, Inc., 4.50%, 12/01/23		250		267,974
AutoZone, Inc.:
3.70%, 04/15/22		50		51,595
3.13%, 07/15/23(a)		250		257,348
3.25%, 04/15/25(a)		165		172,048
3.75%, 04/18/29(a)		1,000		1,059,237
Costco Wholesale Corp.:
2.25%, 02/15/22		85		85,911
3.00%, 05/18/27		1,500		1,582,434
Dollar Tree, Inc.:
3.70%, 05/15/23		2,500		2,605,121
4.20%, 05/15/28(a)		1,000		1,072,744
Home Depot, Inc.:
2.00%, 04/01/21		500		501,211
4.40%, 04/01/21		150		154,129
2.63%, 06/01/22		2,750		2,805,863
3.35%, 09/15/25		2,500		2,671,509
2.13%, 09/15/26(a)		500		499,769
2.80%, 09/14/27		500		520,121
3.90%, 12/06/28		440		494,157
5.88%, 12/16/36		100		138,048
5.40%, 09/15/40(a)		500		663,463
4.20%, 04/01/43		750		870,472
4.40%, 03/15/45(a)		2,250		2,689,397
4.25%, 04/01/46		1,000		1,179,249
3.90%, 06/15/47		500		565,864
4.50%, 12/06/48		1,000		1,235,330
3.50%, 09/15/56		140		145,813
Lowe’s Cos., Inc.:
3.80%, 11/15/21		250		257,516
3.12%, 04/15/22(a)		1,600		1,639,047
3.38%, 09/15/25		500		528,257
2.50%, 04/15/26		955		961,447
3.65%, 04/05/29(a)		500		534,761
4.25%, 09/15/44		250		269,624
4.38%, 09/15/45		1,000		1,116,247
3.70%, 04/15/46		250		255,029
4.05%, 05/03/47		1,000		1,080,339
4.55%, 04/05/49		500		590,339
Macy’s Retail Holdings, Inc.:
3.88%, 01/15/22		168		171,220
2.88%, 02/15/23(a)		1,000		996,915
3.63%, 06/01/24		250		252,575
4.50%, 12/15/34		60		57,104
QVC, Inc.:
5.45%, 08/15/34		200		192,017
5.95%, 03/15/43		350		327,919
Tapestry, Inc., 3.00%, 07/15/22		1,000		1,012,838
TJX Cos., Inc., 2.25%, 09/15/26		2,500		2,512,285
				35,044,286
Technology Hardware, Storage & Peripherals — 0.5%
Adobe, Inc., 3.25%, 02/01/25		70		73,952

SCHEDULE OF INVESTMENTS 49

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Technology Hardware, Storage & Peripherals (continued)
Apple, Inc.:
2.25%, 02/23/21	$	500	$	502,976
1.55%, 08/04/21(a)		1,000		996,249
2.50%, 02/09/22		1,000		1,015,085
1.70%, 09/11/22		2,500		2,498,241
2.10%, 09/12/22(a)		500		505,039
2.40%, 01/13/23		1,000		1,016,609
2.85%, 02/23/23		250		257,149
2.40%, 05/03/23		2,000		2,034,127
3.45%, 05/06/24(a)		1,000		1,062,037
1.80%, 09/11/24		3,635		3,612,470
2.50%, 02/09/25		140		142,605
3.20%, 05/13/25		750		792,517
3.25%, 02/23/26		2,660		2,817,141
2.45%, 08/04/26		1,410		1,430,136
3.35%, 02/09/27		2,000		2,130,372
3.20%, 05/11/27		1,000		1,055,211
2.90%, 09/12/27		1,000		1,041,141
3.00%, 11/13/27(a)		1,000		1,049,148
2.20%, 09/11/29		1,235		1,211,815
4.50%, 02/23/36		250		303,818
3.85%, 05/04/43		1,250		1,401,414
4.45%, 05/06/44		250		305,031
3.45%, 02/09/45		350		368,940
4.38%, 05/13/45		500		607,160
4.65%, 02/23/46		2,980		3,739,163
3.85%, 08/04/46(a)		750		845,851
4.25%, 02/09/47		250		299,342
3.75%, 11/13/47		1,250		1,388,203
2.95%, 09/11/49(a)		1,250		1,211,989
Dell International LLC/EMC Corp.(b):
4.42%, 06/15/21		500		514,556
5.45%, 06/15/23		3,000		3,254,218
4.00%, 07/15/24		1,000		1,047,724
6.02%, 06/15/26		3,090		3,557,208
5.30%, 10/01/29(a)		1,250		1,409,486
8.10%, 07/15/36(a)		500		657,469
8.35%, 07/15/46		850		1,171,246
Hewlett Packard Enterprise Co.:
4.40%, 10/15/22		1,500		1,584,944
2.25%, 04/01/23		1,000		998,995
4.90%, 10/15/25		1,750		1,945,264
6.20%, 10/15/35		500		599,833
6.35%, 10/15/45		250		301,033
HP, Inc.:
4.05%, 09/15/22		1,000		1,044,830
6.00%, 09/15/41		650		720,722
NetApp, Inc., 3.38%, 06/15/21		105		106,751
				54,629,210
Textiles, Apparel & Luxury Goods — 0.0%
NIKE, Inc.:
3.88%, 11/01/45(a)		500		568,353
3.38%, 11/01/46		1,500		1,585,180
VF Corp., 3.50%, 09/01/21		100		102,113
				2,255,646
Tobacco — 0.3%
Altria Group, Inc.:
4.75%, 05/05/21		1,000		1,036,357
2.85%, 08/09/22(a)		1,500		1,528,967
4.00%, 01/31/24(a)		250		265,279
4.80%, 02/14/29		4,000		4,458,660
5.80%, 02/14/39		1,000		1,176,515
4.50%, 05/02/43		400		408,819

Security	Par (000)			Value
Tobacco (continued)
5.38%, 01/31/44	$	820		$	926,533
3.88%, 09/16/46		1,250			1,153,988
5.95%, 02/14/49		1,000			1,212,469
BAT Capital Corp.:
2.76%, 08/15/22(a)		3,000			3,044,223
3.22%, 08/15/24		1,250			1,278,598
3.56%, 08/15/27(a)		1,000			1,021,026
3.46%, 09/06/29(a)		500			505,830
4.39%, 08/15/37		1,250			1,265,826
4.54%, 08/15/47		1,700			1,709,729
4.76%, 09/06/49		750			775,465
Philip Morris International, Inc.:
4.13%, 05/17/21		50	��		51,532
2.63%, 03/06/23(a)		250			254,160
2.13%, 05/10/23		1,000			1,003,048
3.25%, 11/10/24		1,000			1,050,213
3.38%, 08/11/25(a)		750			788,941
2.75%, 02/25/26		415			420,840
3.13%, 08/17/27(a)		1,000			1,037,198
6.38%, 05/16/38(a)		2,000			2,763,673
4.50%, 03/20/42		50			56,825
3.88%, 08/21/42(a)		350			364,610
4.13%, 03/04/43		450			483,368
4.88%, 11/15/43		250			298,956
4.25%, 11/10/44		365			403,587
Reynolds American, Inc.:
4.45%, 06/12/25		1,000			1,076,885
5.70%, 08/15/35		325			377,861
6.15%, 09/15/43		150			176,238
5.85%, 08/15/45(a)		750			860,770
					33,236,989
Trading Companies & Distributors — 0.0%
GATX Corp.:
3.25%, 09/15/26		750			763,562
4.70%, 04/01/29(a)		1,000			1,114,937
					1,878,499
Water Utilities — 0.0%
American Water Capital Corp.:
3.40%, 03/01/25		250			262,187
2.95%, 09/01/27(a)		500			511,112
3.75%, 09/01/28		1,500			1,621,382
3.45%, 06/01/29		500			528,937
4.30%, 09/01/45		250			284,403
3.75%, 09/01/47		500			529,509
4.15%, 06/01/49		500			566,416
					4,303,946
Wireless Telecommunication Services — 0.2%
America Movil SAB de CV:
3.13%, 07/16/22		3,500			3,578,750
3.63%, 04/22/29		1,400			1,479,188
6.13%, 03/30/40(a)		250			335,156
4.38%, 07/16/42(a)		850			949,078
4.38%, 04/22/49		1,000			1,146,560
Rogers Communications, Inc.:
3.00%, 03/15/23		650			666,183
3.63%, 12/15/25(a)		565			602,658
2.90%, 11/15/26(a)		1,000			1,019,013
5.00%, 03/15/44(a)		250			302,987
4.30%, 02/15/48		750			835,675
4.35%, 05/01/49		1,500			1,679,388
3.70%, 11/15/49		400			403,801

50 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Wireless Telecommunication Services (continued)
Vodafone Group PLC:
3.75%, 01/16/24(a)	$	1,000	$	1,057,807
4.13%, 05/30/25(a)		1,000		1,086,273
4.38%, 05/30/28(a)		1,350		1,496,823
7.88%, 02/15/30		100		139,582
5.00%, 05/30/38		500		579,034
4.38%, 02/19/43		950		1,020,284
5.25%, 05/30/48		2,500		3,003,056
4.88%, 06/19/49		500		579,849
4.25%, 09/17/50		1,190		1,242,125
				23,203,270
Total Corporate Bonds — 25.5% (Cost — $2,690,380,079)				2,856,483,231
Foreign Agency Obligations — 2.9%
African Development Bank:
3.00%, 09/20/23		5,000		5,234,450
Series GDIF, 2.63%, 03/22/21		500		505,672
Series GDIF, 1.25%, 07/26/21		500		496,696
Asian Development Bank:
2.25%, 01/20/21		5,000		5,029,622
1.63%, 03/16/21(a)		750		749,394
2.00%, 02/16/22(a)		2,000		2,013,583
1.88%, 02/18/22		1,000		1,004,185
1.88%, 07/19/22(a)		2,000		2,009,540
1.75%, 09/13/22		2,500		2,505,750
2.75%, 03/17/23		3,750		3,874,641
2.63%, 01/30/24		3,000		3,105,210
2.00%, 04/24/26(a)		1,000		1,004,830
2.75%, 01/19/28(a)		750		795,647
Series 5Y, 1.88%, 08/10/22		500		502,581
Canada Government International Bond, 2.63%, 01/25/22(a)		1,000		1,019,057
Chile Government International Bond:
3.25%, 09/14/21		500		510,000
3.24%, 02/06/28		2,000		2,103,750
3.63%, 10/30/42(a)		350		377,344
3.86%, 06/21/47(a)		1,000		1,110,937
Colombia Government International Bond:
4.38%, 07/12/21		750		774,141
2.63%, 03/15/23		250		251,094
4.00%, 02/26/24		2,750		2,902,109
4.50%, 01/28/26		2,250		2,452,500
3.88%, 04/25/27(a)		1,000		1,060,000
4.50%, 03/15/29		2,500		2,772,656
7.38%, 09/18/37		100		142,000
6.13%, 01/18/41		1,000		1,297,500
5.63%, 02/26/44		950		1,183,641
5.00%, 06/15/45		2,000		2,323,750
5.20%, 05/15/49		1,500		1,809,375
European Bank for Reconstruction & Development:
2.75%, 04/26/21(a)		1,000		1,013,647
2.75%, 03/07/23		1,000		1,032,600
European Investment Bank:
2.00%, 03/15/21		1,500		1,506,019
2.38%, 05/13/21		4,000		4,038,469
1.63%, 06/15/21(a)		2,000		1,998,739
1.38%, 09/15/21(a)		2,000		1,990,575
2.25%, 03/15/22		1,000		1,012,353
2.63%, 05/20/22		10,000		10,223,129
2.00%, 12/15/22(a)		1,000		1,009,169
2.50%, 03/15/23		2,000		2,049,536
2.88%, 08/15/23		1,500		1,560,355

Security	Par (000)		Value
Foreign Agency Obligations (continued)
3.13%, 12/14/23	$	4,000	$	4,212,052
3.25%, 01/29/24(a)		1,000		1,059,557
2.63%, 03/15/24		2,000		2,071,396
2.13%, 04/13/26(a)		1,000		1,012,878
2.38%, 05/24/27		3,500		3,612,265
Export Development Canada:
2.00%, 05/17/22		4,000		4,029,240
2.50%, 01/24/23		2,000		2,048,234
Export-Import Bank of Korea:
4.00%, 01/29/21		3,000		3,067,500
1.88%, 10/21/21		2,000		1,997,500
2.75%, 01/25/22		1,000		1,015,625
3.25%, 11/10/25		500		527,500
3.25%, 08/12/26		500		523,438
FMS Wertmanagement:
1.38%, 06/08/21		1,000		995,224
2.00%, 08/01/22		1,000		1,007,839
2.75%, 03/06/23		500		516,006
Hungary Government International Bond:
6.38%, 03/29/21		5,000		5,275,000
5.38%, 02/21/23		500		549,375
5.75%, 11/22/23		500		564,844
5.38%, 03/25/24		500		562,344
7.63%, 03/29/41		750		1,233,750
Indonesia Government International Bond:
4.10%, 04/24/28		2,000		2,171,250
4.75%, 02/11/29		2,000		2,290,000
4.35%, 01/11/48		1,400		1,543,937
Inter-American Development Bank:
1.88%, 03/15/21		500		501,033
2.63%, 04/19/21		5,000		5,060,322
1.25%, 09/14/21(a)		1,000		993,144
2.13%, 01/18/22(a)		1,000		1,008,649
1.75%, 04/14/22		750		751,179
1.75%, 09/14/22(a)		2,000		2,004,681
2.63%, 01/16/24		5,000		5,169,062
2.00%, 06/02/26		500		503,501
2.38%, 07/07/27		1,000		1,032,644
2.25%, 06/18/29		4,500		4,605,876
3.20%, 08/07/42		750		836,819
4.38%, 01/24/44		300		395,821
International Bank for Reconstruction & Development:
2.00%, 01/26/22		3,000		3,021,490
7.63%, 01/19/23		1,000		1,174,234
1.75%, 04/19/23		1,000		1,001,987
3.00%, 09/27/23(a)		4,000		4,187,582
2.50%, 03/19/24(a)		3,000		3,093,281
2.20%, 09/23/24		5,000		5,005,316
4.75%, 02/15/35		500		653,294
Series GDIF, 1.63%, 03/09/21(a)		1,500		1,499,040
Series GDIF, 1.38%, 05/24/21(a)		4,500		4,482,873
Series GDIF, 2.25%, 06/24/21		1,000		1,008,717
Series GDIF, 2.75%, 07/23/21(a)		2,000		2,033,251
Series GDIF, 1.38%, 09/20/21		1,000		995,201
Series GDIF, 1.63%, 02/10/22		3,500		3,496,825
Series GDIF, 2.50%, 07/29/25		1,000		1,037,250
Series GDIF, 1.88%, 10/27/26		750		749,013
Series GDIF, 2.50%, 11/22/27(a)		2,000		2,084,827
International Finance Corp.:
2.25%, 01/25/21		750		754,495
1.13%, 07/20/21		500		495,769
2.88%, 07/31/23		750		779,566
Israel Government International Bond:
4.00%, 06/30/22		900		945,563

SCHEDULE OF INVESTMENTS 51

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Foreign Agency Obligations (continued)
3.15%, 06/30/23	$	3,000	$	3,124,687
3.25%, 01/17/28		2,000		2,145,000
4.50%, 01/30/43		1,200		1,437,000
Italian Government International Bond:
6.88%, 09/27/23		100		114,643
5.38%, 06/15/33		750		873,572
Japan Bank for International Cooperation:
1.88%, 04/20/21		2,000		2,000,722
1.50%, 07/21/21		500		497,407
2.00%, 11/04/21		2,000		2,004,943
2.50%, 06/01/22		2,000		2,028,110
2.38%, 07/21/22		1,000		1,011,619
2.38%, 11/16/22		2,000		2,026,410
3.25%, 07/20/23		600		626,655
3.38%, 07/31/23(a)		500		524,852
3.38%, 10/31/23		500		526,019
2.50%, 05/23/24		500		510,249
2.38%, 04/20/26(a)		750		759,359
2.25%, 11/04/26		500		501,559
2.75%, 11/16/27		500		520,220
3.25%, 07/20/28		2,000		2,161,180
2.00%, 10/17/29		1,000		975,989
Korea Development Bank:
3.38%, 03/12/23		4,000		4,146,840
2.75%, 03/19/23		1,000		1,017,500
Korea International Bond(a):
4.13%, 06/10/44		250		306,593
3.88%, 09/20/48		2,000		2,407,500
Landwirtschaftliche Rentenbank:
2.25%, 10/01/21		500		505,070
1.75%, 07/27/26(a)		1,000		988,106
Mexico Government International Bond:
3.63%, 03/15/22		4,750		4,898,437
4.00%, 10/02/23		250		263,438
3.60%, 01/30/25		500		523,750
4.13%, 01/21/26		3,000		3,203,437
4.15%, 03/28/27		1,000		1,070,937
4.50%, 04/22/29		500		548,906
6.75%, 09/27/34		150		205,125
6.05%, 01/11/40(a)		4,300		5,596,719
4.75%, 03/08/44		1,700		1,877,969
5.55%, 01/21/45(a)		1,525		1,879,562
4.60%, 01/23/46		1,500		1,625,156
4.35%, 01/15/47		750		790,781
4.60%, 02/10/48		2,000		2,187,500
4.50%, 01/31/50		1,450		1,568,266
Nordic Investment Bank, 1.38%, 10/17/22		2,000		1,982,627
Panama Government International Bond:
3.75%, 03/16/25(a)		3,500		3,722,031
3.88%, 03/17/28		2,500		2,727,344
6.70%, 01/26/36		350		490,875
4.50%, 05/15/47(a)		750		891,797
4.50%, 04/16/50		1,500		1,773,281
3.87%, 07/23/60(a)		400		431,375
Peruvian Government International Bond:
7.35%, 07/21/25		400		505,250
4.13%, 08/25/27		1,000		1,120,000
2.84%, 06/20/30(a)		2,000		2,064,375
8.75%, 11/21/33		441		725,666
6.55%, 03/14/37(a)		250		365,391
5.63%, 11/18/50(a)		1,400		2,043,562
Philippine Government International Bond:
4.00%, 01/15/21(a)		4,500		4,588,594
4.20%, 01/21/24		2,500		2,690,625

Security	Par (000)		Value
Foreign Agency Obligations (continued)
3.75%, 01/14/29	$	3,000	$	3,314,062
7.75%, 01/14/31(a)		1,500		2,216,250
6.38%, 10/23/34		250		354,766
5.00%, 01/13/37		1,000		1,275,937
3.95%, 01/20/40		250		286,328
3.70%, 03/01/41(a)		1,100		1,245,062
3.70%, 02/02/42		2,000		2,264,375
Poland Government International Bond:
5.13%, 04/21/21		3,000		3,125,625
5.00%, 03/23/22		2,050		2,196,062
3.00%, 03/17/23		200		206,125
4.00%, 01/22/24		250		268,181
3.25%, 04/06/26		250		265,000
Province of Alberta Canada:
2.20%, 07/26/22		1,000		1,009,466
1.88%, 11/13/24(a)		1,000		996,741
Province of British Columbia Canada:
2.65%, 09/22/21		1,000		1,015,566
2.00%, 10/23/22		750		755,572
Province of Manitoba Canada, 2.13%, 05/04/22		2,000		2,016,400
Province of Ontario Canada:
2.40%, 02/08/22		1,000		1,012,218
2.55%, 04/25/22		4,000		4,070,320
2.25%, 05/18/22(a)		2,000		2,020,413
2.20%, 10/03/22(a)		2,000		2,021,613
2.50%, 04/27/26		3,000		3,063,786
Province of Quebec Canada:
2.75%, 08/25/21		500		507,915
2.38%, 01/31/22		1,000		1,012,142
2.63%, 02/13/23(a)		250		256,673
2.50%, 04/20/26		2,750		2,823,064
Series QO, 2.88%, 10/16/24		500		522,445
Republic of Italy Government International Bond:
2.38%, 10/17/24		2,000		1,958,473
2.88%, 10/17/29		500		474,464
4.00%, 10/17/49		1,500		1,431,253
Svensk Exportkredit AB:
2.88%, 05/22/21		2,000		2,030,102
2.38%, 03/09/22		1,500		1,519,997
1.63%, 11/14/22		500		498,873
2.88%, 03/14/23		1,000		1,035,540
Uruguay Government International Bond:
8.00%, 11/18/22		150		167,250
4.50%, 08/14/24(a)		1,250		1,352,344
4.38%, 10/27/27(a)		1,000		1,104,375
4.38%, 01/23/31(a)		3,000		3,357,187
5.10%, 06/18/50		2,250		2,702,812
4.98%, 04/20/55		1,000		1,179,062
Total Foreign Agency Obligations — 2.9% (Cost — $314,743,009)				326,643,724
Municipal Bonds — 0.6%
Arizona — 0.0%
Salt River Project Agricultural Improvement & Power District, RB, Build America Bonds, Series A, 4.84%, 01/01/41		220		270,761
California — 0.2%
Bay Area Toll Authority, RB, Build America Bonds, San Francisco Toll Bridge:
SeriesF-2, 6.26%, 04/01/49		750		1,142,017
SeriesS-1, 6.92%, 04/01/40		530		776,418

52 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
California (continued)
SeriesS-1, 7.04%, 04/01/50	$	100	$	160,214
SeriesS-3, 6.91%, 10/01/50		200		323,456
Bay Area Toll Authority, Refunding RB, San Francisco Bay Area Toll Bridge, 2.57%, 04/01/31		95		94,382
City & County of San Francisco California Public Utilities Commission Water Revenue, RB, Build America Bonds,Sub-Series G, 6.95%, 11/01/50		100		155,805
City of Los Angeles California Department of Water & Power, RB, Build America Bonds:
5.72%, 07/01/39		200		271,572
6.60%, 07/01/50		90		143,932
Series D, 6.57%, 07/01/45		675		1,056,193
City of San Francisco CA Public Utilities Commission Water Revenue, Refunding RB, Series A, 3.30%, 11/01/39(e)		115		114,704
County of Los Angeles California Metropolitan Transportation Authority, RB, Build America Bonds, 5.74%, 06/01/39		100		130,439
County of Los Angeles Public Works Financing Authority, RB, 7.62%, 08/01/40		100		154,935
County of San Diego California Regional Transportation Commission, RB, Build America Bonds, Series A, 5.91%, 04/01/48		260		375,066
County of San Diego California Water Authority, RB, Build America Bonds, Series B, 6.14%, 05/01/49		315		445,315
County of San Diego Regional Transportation Commission, Refunding RB, Series A, 3.25%, 04/01/48		175		173,516
East Bay Municipal Utility District Water System Revenue, RB, Build America Bonds, 5.87%, 06/01/40		100		136,855
Foothill-Eastern Transportation Corridor Agency, Refunding RB, Toll Road, Series A:
4.09%, 01/15/49		75		75,050
(AGM), 3.92%, 01/15/53		175		172,914
Los Angeles California Community College District, GO, Build America Bonds, 6.75%, 08/01/49		200		328,384
Los Angeles California Unified School District, GO, Build America Bonds:
5.76%, 07/01/29		300		362,571
5.75%, 07/01/34		850		1,083,750
6.76%, 07/01/34(a)		450		616,383
Regents of the University of California Medical Center Pooled Revenue, RB, Regents, Build America Bonds, Series H, 6.55%, 05/15/48		50		72,180
Regents of the University of California Medical Center Pooled Revenue, Refunding RB, Build America Bonds, Series F, 6.58%, 05/15/49		600		854,040
Santa Clara Valley Transportation Authority, RB, Build America Bonds, Series A, 5.88%, 04/01/32		100		122,377
State of California, GO:
Refunding, Bid Group, Series A, 2.50%, 10/01/29		750		747,855
Build America Bonds, 5.70%, 11/01/21		200		214,140
Build America Bonds, 2.37%, 04/01/22		500		506,440
Build America Bonds, 7.50%, 04/01/34		645		973,460
Build America Bonds, 7.55%, 04/01/39		1,375		2,200,041
Build America Bonds, 7.30%, 10/01/39		600		916,596
Build America Bonds, 7.35%, 11/01/39(a)		800		1,218,464
Build America Bonds, 7.60%, 11/01/40		1,850		3,034,962
State of California, GO, Refunding:
2.80%, 04/01/21		95		96,201
3.38%, 04/01/25		100		106,218
3.50%, 04/01/28		355		380,894

Security	Par (000)		Value
California (continued)
4.50%, 04/01/33	$	200	$	224,704
4.60%, 04/01/38		165		183,805
State of California Department of Water Res. Power Supply Revenue, Refunding RB, Series P, 2.00%, 05/01/22		250		251,227
University of California, RB:
Build America Bonds, 5.77%, 05/15/43		190		251,421
Build America Bonds, 5.95%, 05/15/45		500		674,010
General, Series AD, 4.86%, 05/15/12		300		371,067
General, Series AQ, 4.77%, 05/15/15		405		491,107
General, Series BD, 3.35%, 07/01/29		170		181,902
University of California, Refunding RB:
3.06%, 07/01/25		100		104,456
General, Series AJ, 4.60%, 05/15/31		150		172,641
				22,644,079
Colorado — 0.0%
Regional Transportation District Sales Tax Revenue, RB, Build America Bonds, Series B, 5.84%, 11/01/50		100		145,249
Connecticut — 0.0%
State of Connecticut, GO:
Build America Bonds, Series D, 5.09%, 10/01/30		150		172,220
Series A, 5.85%, 03/15/32		550		699,776
				871,996
District of Columbia — 0.0%
District of Columbia, RB, Build America Bonds, Series E, 5.59%, 12/01/34		200		247,138
District of Columbia Water & Sewer Authority, RB, Series A, 4.81%, 10/01/14		200		256,918
District of Columbia Water & Sewer Authority, Refunding RB, Subordinate Lien, Series A, 3.21%, 10/01/48		160		159,283
Metropolitan Washington Airports Authority Dulles Toll Road Revenue, ARB, Dulles Toll Road Revenue, Build America Bonds, 7.46%, 10/01/46		100		159,328
				822,667
Florida — 0.0%
County of Miami-Dade Florida Aviation Revenue, Refunding RB, Series C, 4.28%, 10/01/41		665		718,000
County of Miami-Dade Florida Water & Sewer System Revenue, Refunding RB, Series C, 3.49%, 10/01/42		70		70,444
State Board of Administration Finance Corp., RB, Series A, 2.64%, 07/01/21		200		202,412
				990,856
Georgia — 0.0%
Municipal Electric Authority of Georgia, Refunding RB, Build America Bonds, Series A:
6.64%, 04/01/57		343		461,321
6.66%, 04/01/57		400		555,912
				1,017,233
Illinois — 0.1%
Chicago O’Hare International Airport, ARB, General Senior Lien, Series C:
4.47%, 01/01/49		165		197,635
4.57%, 01/01/54		165		200,995
Chicago O’Hare International Airport, Refunding ARB, Build America Bonds, Series B, 6.40%, 01/01/40		250		358,723
Chicago Transit Authority, RB:
Build America Bonds, Series B, 6.20%, 12/01/40		435		561,750
Pension Funding, Series A, 6.90%, 12/01/40		530		715,283

SCHEDULE OF INVESTMENTS 53

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Illinois (continued)
Metropolitan Water Reclamation District of Greater Chicago, GO, Build America Bonds, 5.72%, 12/01/38	$	150	$	196,815
State of Illinois, GO, Pension, 5.10%, 06/01/33		4,400		4,739,240
				6,970,441
Massachusetts — 0.0%
Commonwealth of Massachusetts, GO:
Build America Bonds, 5.46%, 12/01/39		500		647,655
Consolidated Loan, Series H, 2.90%, 09/01/49		105		99,958
Refunding Series D, 2.81%, 09/01/43		1,000		950,660
Massachusetts School Building Authority, RB, Build America Bonds, 5.72%, 08/15/39		585		759,979
Massachusetts School Building Authority, Refunding RB, Series B, 3.40%, 10/15/40		125		125,178
				2,583,430
Michigan — 0.0%
Michigan Finance Authority, Refunding RB, Trinity Health Credit Group:
3.08%, 12/01/34		150		149,135
3.38%, 12/01/40		125		125,031
				274,166
Missouri — 0.0%
Health & Educational Facilities Authority of the State of Missouri, RB, Taxable, Washington University, Series A, 3.65%, 08/15/57		240		257,203
Nevada — 0.0%
County of Clark Nevada Department of Aviation, ARB, Build America Bonds, Series C, 6.82%, 07/01/45		450		701,222
New Jersey — 0.1%
New Jersey EDA, RB, Series A (NPFGC), 7.43%, 02/15/29		1,450		1,821,881
New Jersey State Turnpike Authority, RB, Build America Bonds:
Series A, 7.10%, 01/01/41		750		1,147,522
Series F, 7.41%, 01/01/40		900		1,412,208
New Jersey Transportation Trust Fund Authority, RB, Build America Bonds:
Series B, 6.56%, 12/15/40		100		133,355
Series C, 5.75%, 12/15/28		350		403,242
New Jersey Transportation Trust Fund Authority, Refunding RB, Transportation System:
4.08%, 06/15/39		200		198,694
4.13%, 06/15/42		55		54,392
Rutgers — The State University of New Jersey, RB, Rutgers University, Series P, 3.92%, 05/01/19		110		108,642
Rutgers The State University of New Jersey, Refunding RB, Series R, 3.27%, 05/01/43		425		417,801
				5,697,737
New York — 0.1%
City of New York New York,Series A-2, 5.21%, 10/01/31		225		266,461
City of New York New York, GO, Build America Bonds:
5.52%, 10/01/37		500		641,570
Series F1, 6.27%, 12/01/37		300		416,001
City of New York New York Water & Sewer System, Refunding RB, 2nd General Resolution, Build America Bonds, Fiscal 2010, Series EE, 6.01%, 06/15/42		600		851,970

Security	Par (000)		Value
New York (continued)
City of New York Transitional Finance Authority Future Tax Secured Revenue, RB, Build America Bonds, Future Tax Secured,Sub-Series B-1, 5.57%, 11/01/38	$	345	$	440,151
City of New York Water & Sewer System, Refunding RB, 2nd General Resolution, Series GG, Build America Bonds, 5.72%, 06/15/42		300		419,049
Metropolitan Transportation Authority, RB, Build America Bonds:
6.67%, 11/15/39		515		725,347
7.34%, 11/15/39		500		781,500
Series E, 6.81%, 11/15/40		400		570,388
New York City Transitional Finance Authority Future Tax Secured Revenue, RB, Build America Bonds, 5.77%, 08/01/36		100		123,124
New York City Water & Sewer System, RB, Build America Bonds, 2nd General Resolution, Fiscal 2020, Series DD, 5.95%, 06/15/42		115		162,556
New York City Water & Sewer System, Refunding RB, Build America Bonds:
5.88%, 06/15/44		100		143,662
2nd General Resolution, Fiscal 2011, Series AA, 5.44%, 06/15/43		200		272,066
New York State Dormitory Authority, RB, Build America Bonds, 5.60%, 03/15/40		475		613,961
New York State Urban Development Corp., RB, Build America Bonds, 5.77%, 03/15/39		200		241,356
Port Authority of New York & New Jersey, ARB:
192nd Series, 4.81%, 10/15/65		100		126,824
Consolidated, 160th Series, 5.65%, 11/01/40		1,245		1,662,697
Consolidated, 168th Series, 4.93%, 10/01/51		250		323,935
Consolidated, 181th Series, 4.96%, 08/01/46		180		228,346
Port Authority of New York & New Jersey, RB:
159th Series, 6.04%, 12/01/29		200		257,338
182nd Series, 5.31%, 08/01/46		100		110,673
Consolidated Bonds, Series 21, 3.29%, 08/01/69		200		192,246
Port Authority of New York & New Jersey, Refunding ARB, Consolidated,174th Series, 4.46%, 10/01/62		1,300		1,596,179
State of New York Dormitory Authority, Refunding RB:
Series B, 3.14%, 07/01/43		50		49,566
Series F, 3.11%, 02/15/39(e)		350		349,895
State of New York Thruway Authority, Refunding RB, Series M:
2.90%, 01/01/35		500		499,225
3.50%, 01/01/42		160		160,606
State of New York Urban Development Corp., RB, State Personal Income Tax, General Purpose, Series B, 3.90%, 03/15/33		500		537,100
				12,763,792
Ohio — 0.0%
American Municipal Power, Inc., RB, Build America Bonds, Combined Hydroelectric Projects, Series B:
7.83%, 02/15/41		650		1,016,333
8.08%, 02/15/50		500		852,835
JobsOhio Beverage System, Refunding RB, Series B:
3.99%, 01/01/29		100		108,682
4.53%, 01/01/35		100		116,811
Ohio State University, RB:
Build America Bonds, Series C, 4.91%, 06/01/40		200		252,894
Series A, 3.80%, 12/01/46		200		222,128

54 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Ohio (continued)
Ohio Water Development Authority Water Pollution Control Loan Fund, RB, Build America Bonds,Series B-2, 4.88%, 12/01/34	$	100	$	114,949
				2,684,632
Oregon — 0.0%
Oregon School Boards Association, Refunding, GOL, Taxable Pension, Series B (NPFCG), 5.55%, 06/30/28		375		443,186
State of Oregon, GO:
5.76%, 06/01/23		68		72,818
5.89%, 06/01/27		750		894,660
State of Oregon Department of Transportation, RB, Build America Bonds,Sub-Lien, Series A, 5.83%, 11/15/34		125		166,485
				1,577,149
Pennsylvania — 0.0%
University ofPittsburgh-of the Commonwealth System of Higher Education, RB, Commonwealth System of Higher Education, 3.56%, 09/15/19		175		169,726
South Carolina — 0.0%
South Carolina Public Service Authority, RB, Build America Bonds, Series C, 6.45%, 01/01/50		100		146,972
Tennessee — 0.0%
Metropolitan Government Nashville & Davidson County Health & Educational Facilities Board, RB, 4.05%, 07/01/26		350		379,351
Texas — 0.1%
City of San Antonio Texas Electric & Gas Systems Revenue, RB:
4.43%, 02/01/42		170		195,247
Build America Bonds, 5.72%, 02/01/41		200		266,076
Junior Lien, Build America Bonds, 5.81%, 02/01/41		250		343,595
Dallas Area Rapid Transit, RB, Build America Bonds, Senior Lien, Series B, 5.02%, 12/01/48		560		742,902
Dallas-Fort Worth International Airport, Refunding RB, Series A, 3.14%, 11/01/45		65		64,567
North Texas Tollway Authority, RB, Build America Bonds, Series B, 6.72%, 01/01/49		550		862,647
Permanent University Fund — University of Texas System, Refunding RB, 3.38%, 07/01/47		540		568,220
State of Texas, GO, Build America Bonds, Series A, 5.52%, 04/01/39(a)		1,000		1,351,500
Texas Private Activity Bond Surface Transportation Corp., RB, North Tarrant Express Managed Lanes Project, Series B, 3.92%, 12/31/49		425		427,971
Texas Transportation Commission State Highway Fund, RB, 1st Tier, Build America Bonds, Series B, 5.18%, 04/01/30		600		721,020
				5,543,745
Virginia — 0.0%
University of Virginia, RB, Series C, 4.18%, 09/01/17		60		70,076
University of Virginia, Refunding RB, Series A, 3.23%, 09/01/19		120		111,209
				181,285
Washington — 0.0%
State of Washington, GO, Build America Bonds, 5.14%, 08/01/40		200		254,194

Security	Par (000)		Value
Wisconsin — 0.0%
State of Wisconsin, RB, Series A (AGM), 5.70%, 05/01/26	$	90	$	101,139
State of Wisconsin, Refunding RB:
Series A, 3.95%, 05/01/36		600		642,090
Series C, 3.15%, 05/01/27		320		333,696
				1,076,925
Total Municipal Bonds — 0.6% (Cost — $63,326,749)				68,024,811
Non-Agency Mortgage-Backed Securities — 1.2%
Commercial Mortgage-Backed Securities — 1.2%
BANK 2019-BNK18, Series 2019-BN18, Class A4, 3.58%, 05/15/62		2,000		2,152,202
Barclays Commercial Mortgage Trust,Series 2017-C1, Class A4, 3.67%, 02/15/50		2,300		2,467,210
Benchmark Mortgage Trust:
Series2018-B5, Class A4, 4.21%, 07/15/51		3,000		3,356,290
Series2019-B11, Class A4, 3.28%, 05/15/52		4,000		4,212,592
Series2019-B13, Class A4, 2.95%, 08/15/57		8,544		8,748,601
Series2019-B9, Class A5, 4.02%, 03/15/52		3,000		3,323,219
Citigroup Commercial Mortgage Trust:
Series 2013-GC17, Class A4, 4.13%, 11/10/46		750		796,526
Series 2014-GC25, Class A4, 3.64%, 10/10/47		500		526,902
Series 2014-GC25, Class AS, 4.02%, 10/10/47		1,500		1,578,885
Series 2016-GC37, Class A4, 3.31%, 04/10/49		3,500		3,665,889
Series2016-P5, Class A4, 2.94%, 10/10/49		1,000		1,027,335
Series2017-P7, Class A4, 3.71%, 04/14/50		2,250		2,420,694
Commercial Mortgage Trust:
Series 2013-CR09, Class A4, 4.22%, 07/10/45(f)		2,700		2,859,613
Series 2013-CR12, Class A4, 4.05%, 10/10/46		1,300		1,371,968
Series2013-CR8, Class A5, 3.61%, 06/10/46(f)		1,900		1,979,130
Series 2014-UBS2, Class A5, 3.96%, 03/10/47		500		530,401
Series2015-PC1, Class A5, 3.90%, 07/10/50		1,500		1,596,920
Series 2016-CR28, Class A4, 3.76%, 02/10/49		750		800,334
CSAIL Commercial Mortgage Securities Trust:
Series2015-C3, Class A4, 3.72%, 08/15/48		1,000		1,057,482
Series2016-C7, Class A5, 3.50%, 11/15/49		4,800		5,032,056
Series 2018-CX11, Class A5, 4.03%, 04/15/51(f)		4,000		4,384,828
DBJPM Mortgage Trust,Series 2016-C3, Class A5, 2.89%, 08/10/49		7,500		7,671,735
GS Mortgage Securities Corp. II, Series 2018-GS10, Class A5, 4.16%, 07/10/51(f)		3,000		3,332,412
GS Mortgage Securities Trust:
Series2012-GC6, Class A3, 3.48%, 01/10/45		5,280		5,374,209
Series 2012-GCJ9, Class A3, 2.77%, 11/10/45		247		250,087
Series 2015-GC30, Class A4, 3.38%, 05/10/50		600		627,851
Series2015-GS1, Class A3, 3.73%, 11/10/48		2,300		2,457,375
JPMBB Commercial Mortgage Securities Trust:
Series2014-C18, Class A5, 4.08%, 02/15/47		250		266,904
Series2014-C22, Class A4, 3.80%, 09/15/47		300		318,596
JPMBB Commercial Mortgage Securities Trust2015-C31,Series 2015-C31, Class A3, 3.80%, 08/15/48		2,250		2,407,472
JPMDB Commercial Mortgage Securities Trust,Series 2017-C7, Class A5, 3.41%, 10/15/50		6,000		6,334,979
JPMorgan Chase Commercial Mortgage Securities Trust:
Series2011-C5, Class A3, 4.17%, 08/15/46		135		137,499
Series2014-C20, Class A5, 3.80%, 07/15/47		1,400		1,483,800
Series2017-JP7, Class A5, 3.45%, 09/15/50		3,500		3,703,845
Morgan Stanley Bank of America Merrill Lynch Trust:
Series2013-C10, Class A5, 4.08%, 07/15/46(f)		3,750		3,957,780
Series2013-C10, Class AS, 4.08%, 07/15/46(f)		2,500		2,628,402

SCHEDULE OF INVESTMENTS 55

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Series2013-C11, Class A4, 4.15%, 08/15/46(f)	$	11,765	$	12,484,133
Series2014-C16, Class A4, 3.60%, 06/15/47		4,430		4,622,063
Series2015-C24, Class A4, 3.73%, 05/15/48		750		798,443
Morgan Stanley Capital I Trust, Class A4:
Series 2015-UBS8, 3.81%, 12/15/48		1,181		1,260,673
Series2018-H3, 3.91%, 07/15/51		3,000		3,277,085
Series2019-H6, 3.42%, 06/15/52		590		625,758
Morgan Stanley Capital I Trust2019-L3,Series 2019-L3, Class AS, 3.49%, 11/15/29		760		784,240
Wells Fargo Commercial Mortgage Trust:
Series 2013-LC12, Class A4, 4.22%, 07/15/46(f)		200		212,172
Series 2014-LC18, Class ASB, 3.24%, 12/15/47		2,500		2,558,999
Series2015-C27, Class A5, 3.45%, 02/15/48		1,500		1,574,811
Series2015-SG1, Class A4, 3.79%, 09/15/48		5,000		5,331,544
Series2019-C49, Class A5, 4.02%, 03/15/52		3,850		4,253,954
WFRBS Commercial Mortgage Trust:
Series2012-C7, Class A1, 2.30%, 06/15/45		97		97,394
Series2012-C7, Class A2, 3.43%, 06/15/45		800		820,298
Series2013-C11, Class A5, 3.07%, 03/15/45		500		511,540
TotalNon-Agency Mortgage-Backed Securities — 1.2% (Cost — $131,291,755)				134,055,130
Preferred Securities — 0.0%
Capital Trusts — 0.0%
Banks — 0.0%
Goldman Sachs Capital I, 6.35%, 02/15/34		250		324,804
Wells Fargo Capital X, 5.95%, 12/01/86		250		305,122
				629,926
Insurance — 0.0%
Allstate Corp., Series B, 5.75%, 08/15/53(c)		1,250		1,343,838
MetLife, Inc., 6.40%, 12/15/66		600		735,000
Prudential Financial, Inc.(c):
5.63%, 06/15/43		100		107,500
5.38%, 05/15/45(a)		500		540,535
				2,726,873
Total Capital Trusts — 0.0% (Cost — $3,154,809)				3,356,799
Total Preferred Securities — 0.0% (Cost — $3,154,809)				3,356,799
U.S. Government Sponsored Agency Securities — 29.7%
Agency Obligations — 0.8%
Fannie Mae:
1.25%, 08/17/21(a)		8,200		8,156,675
1.38%, 10/07/21		2,000		1,992,403
1.88%, 04/05/22(a)		5,000		5,032,216
2.38%, 01/19/23(a)		490		501,064
2.63%, 01/11/22 - 09/06/24(a)		8,715		9,016,341
6.25%, 05/15/29		5,350		7,235,320
6.63%, 11/15/30		149		212,409
7.25%, 05/15/30		5,550		8,167,196
Federal Farm Credit Banks Funding Corp., 2.85%, 09/20/21		1,705		1,742,028
Federal Home Loan Bank:
2.75%, 12/13/24		5,000		5,240,898
3.00%, 12/09/22		4,910		5,104,714
3.13%, 06/13/25		9,570		10,205,280
5.50%, 07/15/36		2,100		2,951,897
Freddie Mac:
1.13%, 08/12/21(a)		3,032		3,009,633
2.38%, 02/16/21 - 01/13/22(a)		19,715		19,971,006

Security	Par (000)		Value
Agency Obligations (continued)
6.25%, 07/15/32	$	1,300	$	1,872,517
6.75%, 03/15/31		2,800		4,057,503
Tennessee Valley Authority:
3.50%, 12/15/42		140		157,095
5.88%, 04/01/36		2,100		2,980,541
				97,606,736
Commercial Mortgage-Backed Securities — 0.8%
Fannie Mae:
Series2016-M5, Class A2, 2.47%, 04/25/26		6,110		6,135,199
Series2012-M9, Class A2, 2.48%, 04/25/22		1,167		1,174,035
Series2016-M6, Class A2, 2.49%, 05/25/26		7,000		7,085,187
Series2014-M6, Class A2, 2.68%, 05/25/21(f)		83		83,709
Series2014-M2, Class ASV2, 2.78%, 06/25/21(f)		182		182,133
Series2014-M13, Class A2, 3.02%, 08/25/24(f)		500		515,301
Freddie Mac:
Series K026, Class A2, 2.51%, 11/25/22		200		202,770
Series K038, Class A1, 2.60%, 10/25/23		99		99,699
Series K017, Class A2, 2.87%, 12/25/21		6,994		7,082,592
Series K727, Class A2, 2.95%, 07/25/24		5,000		5,152,367
Series K033, Class A2, 3.06%, 07/25/23(f)		100		103,307
Series K066, Class A2, 3.12%, 06/25/27		3,500		3,681,979
Series K052, Class A2, 3.15%, 11/25/25		750		787,381
Series K041, Class A2, 3.17%, 10/25/24		7,500		7,851,657
Series K734, Class A2, 3.21%, 02/25/26		5,700		5,994,350
Series K031, Class A2, 3.30%, 04/25/23(f)		100		103,914
Series K047, Class A2, 3.33%, 05/25/25(f)		7,435		7,856,130
Series K063, Class A2, 3.43%, 01/25/27(f)		5,000		5,352,569
Series K035, Class A2, 3.46%, 08/25/23(f)		2,000		2,093,851
Series K037, Class A2, 3.49%, 01/25/24		2,700		2,839,569
Series K036, Class A2, 3.53%, 10/25/23(f)		1,200		1,261,061
Series K034, Class A2, 3.53%, 07/25/23(f)		3,900		4,090,762
Series K730, Class A2, 3.59%, 01/25/25(f)		9,000		9,545,012
Series K088, Class A2, 3.69%, 01/25/29		500		546,715
Series K076, Class A2, 3.90%, 04/25/28		2,000		2,209,952
Series K081, Class A2, 3.90%, 08/25/28(f)		5,000		5,534,799
Series K013, Class A2, 3.97%, 01/25/21(f)		500		507,456
				88,073,456
Mortgage-Backed Securities — 28.1%
Fannie Mae Mortgage-Backed Securities:
(12 mo. LIBOR US + 1.54%), 2.02%, 06/01/43(g)		329		337,645
2.50%, 09/01/28 - 01/01/50(h)		149,883		150,751,608
3.00%, 01/01/27 - 01/01/50(h)		491,776		502,446,255
3.50%, 02/01/26 - 11/01/51(h)		419,530		436,713,616
(12 mo. LIBOR US + 1.83%), 3.77%, 11/01/40(g)		7		7,091
4.00%, 10/01/25 - 02/01/57(h)		354,877		375,106,915
(12 mo. LIBOR US + 1.75%), 4.35%, 08/01/41(g)		10		10,658
(12 mo. LIBOR US + 1.53%), 4.41%,04/01/43 - 05/01/43(g)		151		156,549
(12 mo. LIBOR US + 1.70%), 4.45%, 08/01/42(g)		41		42,540
4.50%, 05/01/24 - 01/01/50(h)		141,405		150,536,910
5.00%, 11/01/33 - 01/01/50(h)		39,123		42,261,996
5.50%, 04/01/36 - 01/01/50(h)		31,442		34,037,286
6.00%, 03/01/34 - 01/01/50(h)		11,075		12,349,815
6.50%, 07/01/32		86		96,258
7.00%, 02/01/32		12		12,021
Freddie Mac Mortgage-Backed Securities:
2.50%, 07/01/28 - 10/01/49		27,494		27,818,842
3.00%, 03/01/27 - 12/01/49		154,545		158,524,819
3.50%, 03/01/32 - 11/01/49		221,271		230,461,779
4.00%, 05/01/33 - 06/01/49		81,149		85,158,713
(12 mo. LIBOR US + 1.77%), 4.37%, 08/01/41(g)		10		10,285
(12 mo. LIBOR US + 1.50%), 4.37%, 06/01/43(g)		21		21,255

56 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
Mortgage-Backed Securities (continued)
4.50%, 06/01/38 - 01/01/49	$	36,093	$	38,429,049
(12 mo. LIBOR US + 1.82%), 4.52%, 09/01/40(g)		24		24,765
5.00%, 04/01/33 - 04/01/49		7,479		8,048,649
5.50%, 06/01/35 - 01/01/39		138		154,512
6.50%, 06/01/31		20		22,193
8.00%, 12/01/24		62		65,670
Ginnie Mae Mortgage-Backed Securities:
2.50%, 05/20/45 - 01/01/50(h)		5,544		5,583,101
3.00%, 01/20/43 - 01/01/50(h)		231,484		238,671,442
3.50%, 09/20/42 - 01/01/50(h)		302,305		314,265,333
4.00%, 03/15/41 - 01/01/50(h)		186,785		194,603,411
4.50%, 07/15/39 - 01/01/50(h)		87,908		92,454,411
5.00%, 11/15/39 - 01/01/50(h)		38,135		40,479,442
5.50%, 12/15/32 - 04/20/48		538		585,366
6.00%, 03/15/35 - 10/20/38		157		178,027
6.50%, 09/15/36		97		110,686
7.50%, 12/15/23		51		53,613
				3,140,592,526
Total U.S. Government Sponsored Agency Securities — 29.7% (Cost — $3,253,138,779)				3,326,272,718
U.S. Treasury Obligations — 40.9%
U.S. Treasury Bonds:
6.13%, 08/15/29(a)		7,500		10,287,598
5.38%, 02/15/31(a)		6,000		8,058,516
4.50%, 02/15/36(a)		18,000		23,896,406
4.75%, 02/15/37(a)		1,450		1,997,771
5.00%, 05/15/37		9,000		12,755,742
4.38%, 02/15/38		6,000		7,992,188
4.50%, 05/15/38(a)		1,000		1,353,164
3.50%, 02/15/39(a)		11,300		13,563,973
4.25%, 05/15/39		11,775		15,520,002
4.50%, 08/15/39(a)		1,700		2,310,738
4.38%, 11/15/39		4,800		6,434,063
4.63%, 02/15/40(a)		1,230		1,703,262
4.38%, 05/15/40		1,650		2,219,057
3.88%, 08/15/40		3,860		4,873,401
4.25%, 11/15/40(a)		7,528		9,979,599
4.75%, 02/15/41(a)		11,000		15,543,086
4.38%, 05/15/41		12,610		17,027,933
3.75%, 08/15/41		9,550		11,877,813
3.13%, 11/15/41		10,700		12,160,383
3.13%, 02/15/42		34,350		39,040,922
3.00%, 05/15/42(a)		13,480		15,026,514
2.75%, 08/15/42(a)		18,250		19,531,064
2.75%, 11/15/42(a)		42,500		45,451,758
3.13%, 02/15/43		21,000		23,865,352
2.88%, 05/15/43		24,750		27,021,006
3.63%, 08/15/43(a)		7,500		9,216,211
3.75%, 11/15/43(a)		64,700		81,074,660
3.63%, 02/15/44		11,000		13,545,898
3.38%, 05/15/44(a)		7,600		9,013,125
3.13%, 08/15/44		2,000		2,280,078
3.00%, 11/15/44		6,300		7,038,281
2.50%, 02/15/45		23,500		24,034,258
3.00%, 05/15/45		15,600		17,455,547
2.88%, 08/15/45		18,800		20,599,219
3.00%, 11/15/45(a)		15,900		17,829,117
2.50%, 02/15/46		18,600		19,036,664
2.50%, 05/15/46(a)		25,850		26,456,869
2.25%, 08/15/46		26,500		25,818,867
2.88%, 11/15/46		8,500		9,346,680

Security	Par (000)		Value
U.S. Treasury Obligations (continued)
3.00%, 02/15/47(a)	$	9,000	$	10,136,953
3.00%, 05/15/47(a)		18,200		20,498,461
2.75%, 08/15/47(a)		35,500		38,166,660
2.75%, 11/15/47		30,000		32,253,516
3.00%, 02/15/48		8,000		9,016,250
3.13%, 05/15/48(a)		32,500		37,517,188
3.00%, 08/15/48		9,000		10,161,914
3.38%, 11/15/48		14,700		17,782,406
2.88%, 05/15/49		6,500		7,183,770
2.25%, 08/15/49(a)		25,000		24,320,313
2.38%, 11/15/49(a)		62,000		61,968,516
U.S. Treasury Notes:
2.13%, 01/31/21(a)		11,800		11,861,766
3.63%, 02/15/21(a)		2,310		2,360,531
1.13%, 02/28/21		60,000		59,648,437
2.00%, 02/28/21		32,700		32,834,121
1.25%, 03/31/21		9,000		8,958,867
2.25%, 03/31/21		11,500		11,587,598
1.38%, 04/30/21(a)		60,000		59,817,187
2.25%, 04/30/21(a)		50,000		50,421,875
2.63%, 05/15/21(a)		120,000		121,650,000
3.13%, 05/15/21		3,000		3,061,289
2.00%, 05/31/21		5,000		5,027,539
2.63%, 06/15/21		16,000		16,232,500
1.13%, 06/30/21(a)		4,500		4,468,535
2.13%, 06/30/21(a)		20,000		20,157,812
2.63%, 07/15/21(a)		74,000		75,150,469
2.25%, 07/31/21(a)		12,804		12,933,040
2.75%, 08/15/21		20,000		20,364,844
1.13%, 08/31/21		18,000		17,861,484
2.00%, 08/31/21		8,500		8,556,113
2.75%, 09/15/21		50,000		50,958,984
1.13%, 09/30/21		20,000		19,839,062
2.13%, 09/30/21(a)		122,900		123,999,379
1.25%, 10/31/21		8,000		7,951,875
1.50%, 10/31/21		150,000		149,794,921
2.00%, 10/31/21(a)		9,000		9,067,148
2.00%, 11/15/21(a)		13,700		13,808,101
1.75%, 11/30/21		16,000		16,049,375
1.88%, 11/30/21(a)		53,000		53,308,476
2.00%, 12/31/21(a)		12,000		12,096,094
2.13%, 12/31/21(a)		10,000		10,105,078
2.50%, 01/15/22		25,000		25,452,149
1.50%, 01/31/22(a)		3,500		3,494,805
1.88%, 01/31/22(a)		59,000		59,345,703
1.75%, 02/28/22		1,500		1,505,625
1.88%, 02/28/22		5,000		5,030,664
1.75%, 03/31/22(a)		9,100		9,134,125
1.88%, 03/31/22		18,000		18,114,609
2.25%, 04/15/22		20,000		20,293,750
1.75%, 04/30/22		10,000		10,037,500
1.88%, 04/30/22		5,000		5,032,422
1.75%, 05/31/22(a)		3,000		3,011,719
1.75%, 06/30/22(a)		18,000		18,074,531
2.13%, 06/30/22(a)		18,000		18,237,656
1.88%, 07/31/22		40,000		40,282,812
2.00%, 07/31/22		15,000		15,154,688
1.88%, 08/31/22(a)		34,958		35,214,723
1.50%, 09/15/22		20,000		19,953,906
1.75%, 09/30/22(a)		23,000		23,092,539
1.88%, 09/30/22		10,000		10,076,172
1.38%, 10/15/22		20,000		19,878,125
1.88%, 10/31/22		17,000		17,126,836

SCHEDULE OF INVESTMENTS 57

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio (Percentages shown are based on Net Assets)

Security	Par (000)		Value
U.S. Treasury Obligations (continued)
2.00%, 10/31/22	$	10,000	$	10,109,766
1.63%, 11/15/22(a)		50,000		50,037,110
7.63%, 11/15/22(a)		3,400		3,974,281
2.00%, 11/30/22(a)		36,000		36,406,406
2.13%, 12/31/22		45,000		45,685,547
1.75%, 01/31/23		20,000		20,082,812
2.00%, 02/15/23		8,000		8,093,750
1.50%, 02/28/23(a)		10,200		10,164,539
1.50%, 03/31/23		31,500		31,385,566
1.63%, 04/30/23		19,000		18,998,516
2.75%, 04/30/23(a)		26,600		27,563,211
1.75%, 05/15/23		1,000		1,003,867
1.63%, 05/31/23		4,000		4,000,156
1.38%, 06/30/23		26,500		26,269,160
2.63%, 06/30/23(a)		133,000		137,499,140
1.25%, 07/31/23		4,000		3,946,406
2.75%, 07/31/23(a)		46,000		47,768,125
2.50%, 08/15/23		16,000		16,479,375
6.25%, 08/15/23		2,050		2,381,443
1.38%, 08/31/23(a)		38,000		37,649,688
1.38%, 09/30/23(a)		4,000		3,960,156
2.88%, 09/30/23(a)		6,000		6,266,484
1.63%, 10/31/23		15,000		14,986,523
2.75%, 11/15/23		28,000		29,142,969
2.13%, 11/30/23		54,000		54,961,875
2.25%, 12/31/23(a)		11,000		11,250,508
2.63%, 12/31/23		10,000		10,373,047
2.25%, 01/31/24		40,000		40,926,562
2.50%, 01/31/24		65,000		67,140,430
2.75%, 02/15/24(a)		15,000		15,646,289
2.13%, 02/29/24		13,000		13,241,211
2.13%, 03/31/24		10,000		10,185,938
2.00%, 04/30/24		22,000		22,301,641
2.50%, 05/15/24		22,300		23,074,402
2.00%, 05/31/24		5,700		5,779,043
1.75%, 06/30/24(a)		70,000		70,221,484
2.00%, 06/30/24		40,000		40,554,688
2.38%, 08/15/24(a)		7,500		7,729,688
1.88%, 08/31/24(a)		5,000		5,043,164
1.50%, 09/30/24(a)		75,000		74,375,977
2.13%, 09/30/24(a)		20,000		20,400,000
1.50%, 10/31/24		50,000		49,583,985
2.25%, 10/31/24(a)		5,000		5,130,859
2.25%, 11/15/24(a)		57,000		58,494,024
7.50%, 11/15/24(a)		5,000		6,350,391
2.13%, 11/30/24		15,000		15,306,445
2.25%, 12/31/24		55,000		56,465,234
2.00%, 02/15/25(a)		21,984		22,301,737
7.63%, 02/15/25		375		483,457
2.75%, 02/28/25		30,000		31,551,563
2.13%, 05/15/25		24,000		24,495,000
2.75%, 06/30/25		28,000		29,494,063
2.88%, 07/31/25(a)		50,000		53,021,484
2.00%, 08/15/25		56,800		57,578,781
6.88%, 08/15/25(a)		8,000		10,205,625
3.00%, 09/30/25(a)		38,000		40,591,719
3.00%, 10/31/25(a)		15,000		16,031,836
2.25%, 11/15/25		16,600		17,051,961
2.63%, 01/31/26		15,000		15,734,180
1.63%, 02/15/26(a)		68,000		67,402,344
6.00%, 02/15/26(a)		7,660		9,537,274
1.63%, 05/15/26		36,350		35,982,240
1.50%, 08/15/26		27,500		26,968,262

Security	Par (000)		Value
U.S. Treasury Obligations (continued)
6.75%, 08/15/26(a)	$	7,500	$	9,823,535
1.63%, 09/30/26		15,000		14,821,289
1.63%, 10/31/26		60,000		59,252,344
2.00%, 11/15/26		15,000		15,174,023
6.50%, 11/15/26		900		1,173,586
1.63%, 11/30/26		30,000		29,620,313
6.63%, 02/15/27(a)		3,500		4,624,922
2.38%, 05/15/27		13,000		13,484,961
2.25%, 08/15/27(a)		28,500		29,313,809
6.38%, 08/15/27		3,000		3,970,078
2.25%, 11/15/27(a)		98,510		101,311,378
2.75%, 02/15/28		20,000		21,322,656
2.88%, 05/15/28		14,000		15,078,984
2.88%, 08/15/28(a)		70,000		75,496,093
3.13%, 11/15/28(a)		30,000		33,008,203
5.25%, 11/15/28(a)		9,000		11,465,508
2.63%, 02/15/29(a)		23,884		25,330,102
5.25%, 02/15/29(a)		5,000		6,397,852
1.63%, 08/15/29(a)		75,000		73,122,070
Total U.S. Treasury Obligations — 40.9% (Cost — $4,424,571,917)				4,569,335,404
Total Long-Term Investments — 101.3% (Cost — $10,931,359,590)				11,335,771,331
	Shares
Short-Term Securities — 19.9%
BlackRock Cash Funds: Institutional, SL Agency Shares,
1.87%(i)(j)(k)		2,221,384,022		2,222,272,575
BlackRock Cash Funds: Treasury, SL Agency Shares,
1.55%(i)(k)		100,000		100,000
Total Short-Term Securities — 19.9% (Cost — $2,222,030,290)				2,222,372,575
Total Investments Before TBA Sale Commitments — 121.2% (Cost — $13,153,389,880)				13,558,143,906
TBA Sale Commitments(h) — (0.6%)
Mortgage-Backed Securities — (0.6%)
Fannie Mae Mortgage-Backed Securities:
2.50%, 01/16/35	USD	8,440		(8,517,147	)
3.00%, 01/16/35 - 01/14/50		35,967		(36,528,334	)
3.50%, 01/14/50		3,287		(3,381,373	)
4.50%, 01/14/50		8,119		(8,548,102	)
Ginnie Mae Mortgage-Backed Securities:
3.00%, 01/21/50		4,183		(4,297,542	)
3.50%, 01/21/50		6,297		(6,489,600	)
Total TBA Sale Commitments — (0.6)% (Proceeds — $67,631,073)				(67,762,098	)
Total Investments, Net of TBA Sale Commitments — 120.6% (Cost — $13,085,758,807)				13,490,381,808
Liabilities in Excess of Other Assets — (20.6)%				(2,307,737,256	)
Net Assets — 100.0%			$	11,182,644,552

^(a)  Security, or a portion of the security, is on loan.

^(b)  Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

^(c)  Variable rate security. Security may be issued at a fixed coupon rate, which converts to a variable rate at a specified date. Rate shown is the rate in effect as of period end.

58 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 U.S. Total Bond Index Master Portfolio

^(d)  Step-up bond that pays an initial coupon rate for the first period and then a higher coupon rate for the following periods. Rate as of period end.

^(e)  When-issued security.

^(f)  Variable or floating rate security, which interest rate adjusts periodically based on changes in current interest rates and prepayments on the underlying pool of assets. Rate shown is the rate in effect as of period end.

^(g)  Variable rate security. Rate shown is the rate in effect as of period end.

^(h)  Represents or includes a TBA transaction.

⁽ⁱ⁾  Annualized7-day yield as of period end.

^(j)  All or a portion of security was purchased with the cash collateral from loaned securities

^(k)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliate	Shares Held at 12/31/18		Net Activity		Shares Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)		Change in Unrealized Appreciation (Depreciation)
BlackRock Cash Funds: Institutional, SL Agency Shares		794,588,139		1,426,795,883		2,221,384,022	$	2,222,272,575	$	21,095,816	(b)	$	385,746	$	296,148
BlackRock Cash Funds: Treasury, SL Agency Shares		100,000		—		100,000		100,000		2,129			—		—
							$	2,222,372,575	$	21,097,945		$	385,746	$	296,148

^(a) Includes net capital gain distributions, if applicable.

^(b) All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

For Master Portfolio compliance purposes, the Master Portfolio’s industry classifications refer to one or more of the industry sub-classifications used by one or more widely recognized market indexes or ratings group indexes, and/or as defined by the investment advisor. These definitions may not apply for purposes of this report, which may combine such industrysub-classifications for reporting ease.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments. For information about the Master Portfolio’s policy regarding valuation of investments, refer to the Notes to Financial Statements.

The following table summarizes the Master Portfolio’s investments categorized in the disclosure hierarchy:

	Level 1		Level 2			Level 3		Total
Assets:
Investments:
Long-Term Investments(a)	$	—	$	11,335,771,331		$	—	$	11,335,771,331
Short-Term Securities		2,222,372,575		—			—		2,222,372,575
Liabilities:
Investments:
TBA Sale Commitments	$	—	$	(67,762,098	)	$	—	$	(67,762,098	)
	$	2,222,372,575	$	11,268,009,233		$	—	$	13,490,381,808

^(a) See above Schedule of Investments for values in each industry/state/security type.

See notes to financial statements.

SCHEDULE OF INVESTMENTS 59

Statement of Assets and Liabilities

December 31, 2019

	U.S. Total Bond Index Master Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $1,530,998,508, cost — $10,931,359,590)	$	11,335,771,331
Investments at value — affiliated (cost — $2,222,030,290)		2,222,372,575
Cash		11,653
Receivables:
Investments sold		137,735,940
Securities lending income — affiliated		616,195
TBA sale commitments		67,631,073
Contributions from investors		10,952,880
Dividends — unaffiliated		1,058,092
Interest — unaffiliated		64,663,203
Principal paydowns		2,594
Total assets		13,840,815,536
LIABILITIES
Cash collateral on securities loaned at value		1,574,802,234
TBA sale commitments at value (proceeds — $67,631,073)		67,762,098
Payables:
Investments purchased		1,014,285,376
Withdrawals to investors		644,602
Investment advisory fees		593,689
Trustees’ fees		42,194
Other accrued expenses		40,791
Total liabilities		2,658,170,984
NET ASSETS	$	11,182,644,552
NET ASSETS CONSIST OF
Investors’ capital	$	10,778,137,162
Net unrealized appreciation (depreciation)		404,507,390
NET ASSETS	$	11,182,644,552

See notes to financial statements.

60 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Operations

Year Ended December 31, 2019

	U.S. Total Bond Index Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	16,659,271
Interest — unaffiliated		267,413,171
Securities lending income — affiliated — net		4,438,674
Other income — affiliated		529,200	(a)
Total investment income		289,040,316
EXPENSES
Investment advisory		3,937,273
Trustees		145,562
Professional		49,969
Total expenses		4,132,804
Less fees waived and/or reimbursed by the Manager		(681,997	)
Total expenses after fees waived and/or reimbursed		3,450,807
Net investment income		285,589,509
REALIZED AND UNREALIZED GAIN
Net realized gain from:
Investments — affiliated		385,746
Investments — unaffiliated		39,605,176
		39,990,922
Net change in unrealized appreciation on:
Investments — affiliated		296,148
Investments — unaffiliated		474,538,987
		474,835,135
Net realized and unrealized gain		514,826,057
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	800,415,566

^(a)  Includes a reimbursement from an affiliate of $529,200 relating to an operating event.

See notes to financial statements.

FINANCIAL STATEMENTS 61

Statements of Changes in Net Assets

	U.S. Total Bond Index Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	285,589,509		$	170,905,829
Net realized gain (loss)		39,990,922			(35,233,237	)
Net change in unrealized appreciation (depreciation)		474,835,135			(74,163,353	)
Net increase in net assets resulting from operations		800,415,566			61,509,239
CAPITAL TRANSACTIONS
Proceeds from contributions		3,801,148,795			6,455,698,739
Value of withdrawals		(1,746,558,904	)		(3,237,334,937	)
Net increase in net assets derived from capital transactions		2,054,589,891			3,218,363,802
NET ASSETS
Total increase in net assets		2,855,005,457			3,279,873,041
Beginning of year		8,327,639,095			5,047,766,054
End of year	$	11,182,644,552		$	8,327,639,095

See notes to financial statements.

62 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights

(For a share outstanding throughout each period)

	U.S. Total Bond Index Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		8.72	%(a)		(0.07	)%		3.40	%		2.55	%		0.40	%
Ratios to Average Net Assets(b)
Total expenses		0.04	%		0.04	%		0.04	%		0.04	%		0.06	%
Total expenses after fees waived and/or reimbursed and paid indirectly		0.04	%		0.03	%		0.03	%		0.03	%		0.04	%
Net investment income		2.90	%		2.74	%		2.22	%		2.02	%		1.93	%
Supplemental Data
Net assets, end of year (000)	$	11,182,645		$	8,327,639		$	5,047,766		$	3,018,237		$	1,588,374
Portfolio turnover rate(c)(d)		158	%		274	%		345	%		278	%		356	%

^(a)  Includes payment received from an affiliate, which had no impact on the Fund’s total return.

^(b)  Excludes expenses incurred indirectly as a result of investments in underlying funds:

		Year Ended December 31,
	2019			2018			2017			2016			2015
Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		0.02	%

^(c)  Portfolio turnover rates include TBA transactions, if any.

^(d)  Includes mortgage dollar roll transactions (“MDRs”). Additional information regarding portfolio turnover rate is as follows:

		Year Ended December 31,
	2019			2018			2017			2016			2015
Portfolio turnover rate(excluding MDRs)		97	%		162	%		193	%		164	%		300	%

FINANCIAL HIGHLIGHTS 63

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. U.S. Total Bond Index Master Portfolio (the “Master Portfolio”) is a series of MIP. The Master Portfolio is classified as diversified.

The Master Portfolio, together with certain other registered investment companies advised by BlackRock Fund Advisors (“BFA” or the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain. Interest income, including amortization and accretion of premiums and discounts on debt securities, is recognized on an accrual basis.

Segregation and Collateralization:In cases where the Master Portfolio enters into certain investments (e.g., dollar rolls and TBA sale commitments) that would be treated as “senior securities” for 1940 Act purposes, the Master Portfolio may segregate or designate on itsbooks and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the Master Portfolio may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Recent Accounting Standards:The Trust has adopted Financial Accounting Standards Board Accounting Standards Update2017-08 to amend the amortization period for certain purchased callable debt securities held at a premium. Under the new standard, the Trust has changed the amortization period for the premium on certain purchased callable debt securities withnon-contingent call features to the earliest call date. In accordance with the transition provisions of the standard, the Trust applied the amendments on a modified retrospective basis beginning with the fiscal period ended December 31, 2019. The adjusted cost basis of securities at December 31, 2018 is $9,084,044,723. This change in accounting policy has been made to comply with the newly issued accounting standard and had no impact on accumulated earnings (loss) or the net asset value of the Trust.

Indemnifications:In the normal course of business, the Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. The Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Master Portfolio, which cannot be predicted with any certainty.

Other: Expenses directly related to the Master Portfolio are charged to the Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the New York Stock Exchange (“NYSE”) (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board of Trustees of MIP (the “Board”). The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of the Master Portfolio’s assets and liabilities:

• Fixed-income securities for which market quotations are readily available are generally valued using the last available bid prices or current market quotations provided by independent dealers or third party pricing services. Floating rate loan interests are valued at the mean of the bid prices from one or more independent brokers or dealers as obtained from a third party pricing service. Pricing services generally value fixed-income securities assuming orderly transactions of an institutional round lot size, but a fund may hold or transact in such securities in smaller, odd lot sizes. Odd lots may trade at lower prices than institutional round lots. The pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values, including transaction data (e.g., recent representative bids and offers), credit quality information, perceived market movements, news, and other relevant information. Certain fixed-income securities, including asset-backed and mortgage related securities may be valued based on valuation models that consider the estimated cash flows of each tranche of the entity, establish a benchmark yield and develop an estimated tranche specific spread to the benchmark yield based on the unique attributes of the tranche. The amortized cost method of valuation may be used with respect to debt obligations with sixty days or less remaining to maturity unless the Manager determines such method does not represent fair value.

64 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

• Municipal investments (including commitments to purchase such investments on a “when-issued” basis) are valued on the basis of prices provided by dealers or pricing services. In determining the value of a particular investment, pricing services may use certain information with respect to transactions in such investments, quotations from dealers, pricing matrixes, market transactions in comparable investments and information with respect to various relationships between investments.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• To-be-announced (“TBA”) commitments are valued on the basis of last available bid prices or current market quotations provided by pricing services.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that the Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market-corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments is based on the pricing transparency of the investments and is not necessarily an indication of the risks associated with investing in those securities.

4. SECURITIES AND OTHER INVESTMENTS

Asset-Backed and Mortgage-Backed Securities:Asset-backed securities are generally issued as pass-through certificates or as debt instruments. Asset-backed securities issued as pass-through certificates represent undivided fractional ownership interests in an underlying pool of assets. Asset-backed securities issued as debt instruments, which are also known as collateralized obligations, are typically issued as the debt of a special purpose entity organized solely for the purpose of owning such assets and issuing such debt. Asset-backed securities are often backed by a pool of assets representing the obligations of a number of different parties. The yield characteristics of certain asset-backed securities may differ from traditional debt securities. One such major difference is that all or a principal part of the obligations may be prepaid at any time because the underlying assets (i.e., loans) may be prepaid at any time. As a result, a decrease in interest rates in the market may result in increases in the level of prepayments as borrowers, particularly mortgagors, refinance and repay their loans. An increased prepayment rate with respect to an asset-backed security will have the effect of shortening the maturity of the security. In addition, the Master Portfolio may subsequently have to reinvest the proceeds at lower interest rates. If the Master Portfolio has purchased such an asset-backed security at a premium, a faster than anticipated prepayment rate could result in a loss of principal to the extent of the premium paid.

For mortgage pass-through securities (the “Mortgage Assets”) there are a number of important differences among the agencies and instrumentalities of the U.S. Government that issue mortgage-related securities and among the securities that they issue. For example, mortgage-related securities guaranteed by Ginnie Mae are guaranteed as to the timely payment of principal and interest by Ginnie Mae and such guarantee is backed by the full faith and credit of the United States. However, mortgage-related securities issued by Freddie Mac and Fannie Mae, including Freddie Mac and Fannie Mae guaranteed mortgage pass-through certificates, which are solely the obligations of Freddie Mac and Fannie Mae, are not backed by or entitled to the full faith and credit of the United States, but are supported by the right of the issuer to borrow from the U.S. Treasury.

Non-agency mortgage-backed securities are securities issued bynon-governmental issuers and have no direct or indirect government guarantees of payment and are subject to various risks.Non-agency mortgage loans are obligations of the borrowers thereunder only and are not typically insured or guaranteed by any other person or entity. The ability of a borrower to repay a loan is dependent upon the income or assets of the borrower. A number of factors, including a general economic downturn, acts of God, terrorism, social unrest and civil disturbances, may impair a borrower’s ability to repay its loans.

NOTESTO FINANCIAL STATEMENTS 65

Notes to Financial Statements  (continued)

Multiple Class Pass-Through Securities: Multiple class pass-through securities, including collateralized mortgage obligations (“CMOs”) and commercial mortgage-backed securities, may be issued by Ginnie Mae, U.S. Government agencies or instrumentalities or by trusts formed by private originators of, or investors in, mortgage loans. In general, CMOs are debt obligations of a legal entity that are collateralized by a pool of residential or commercial mortgage loans or Mortgage Assets. The payments on these are used to make payments on the CMOs or multiple pass-through securities. Multiple class pass-through securities represent direct ownership interests in the Mortgage Assets. Classes of CMOs include interest only (“IOs”), principal only (“POs”), planned amortization classes and targeted amortization classes. IOs and POs are stripped mortgage-backed securities representing interests in a pool of mortgages, the cash flow from which has been separated into interest and principal components. IOs receive the interest portion of the cash flow while POs receive the principal portion. IOs and POs can be extremely volatile in response to changes in interest rates. As interest rates rise and fall, the value of IOs tends to move in the same direction as interest rates. POs perform best when prepayments on the underlying mortgages rise since this increases the rate at which the principal is returned and the yield to maturity on the PO. When payments on mortgages underlying a PO are slower than anticipated, the life of the PO is lengthened and the yield to maturity is reduced. If the underlying Mortgage Assets experience greater than anticipated prepayments of principal, the Master Portfolio’s initial investment in the IOs may not fully recoup.

Capital Securities and Trust Preferred Securities: Capital securities, including trust preferred securities, are typically issued by corporations, generally in the form of interest-bearing notes with preferred securities characteristics. In the case of trust preferred securities, an affiliated business trust of a corporation issues these securities, generally in the form of beneficial interests in subordinated debentures or similarly structured securities. The securities can be structured with either a fixed or adjustable coupon that can have either a perpetual or stated maturity date. For trust preferred securities, the issuing bank or corporation pays interest to the trust, which is then distributed to holders of these securities as a dividend. Dividends can be deferred without creating an event of default or acceleration, although maturity cannot take place unless all cumulative payment obligations have been met. The deferral of payments does not affect the purchase or sale of these securities in the open market. These securities generally are rated below that of the issuing company’s senior debt securities and are freely callable at the issuer’s option.

Forward Commitments, When-Issued and Delayed Delivery Securities: The Master Portfolio may purchase securities on a when-issued basis and may purchase or sell securities on a forward commitment basis. Settlement of such transactions normally occurs within a month or more after the purchase or sale commitment is made. The Master Portfolio may purchase securities under such conditions with the intention of actually acquiring them, but may enter into a separate agreement to sell the securities before the settlement date. Since the value of securities purchased may fluctuate prior to settlement, the Master Portfolio may be required to pay more at settlement than the security is worth. In addition, the Master Portfolio is not entitled to any of the interest earned prior to settlement. When purchasing a security on a delayed delivery basis, the Master Portfolio assumes the rights and risks of ownership of the security, including the risk of price and yield fluctuations. In the event of default by the counterparty, the Master Portfolio’s maximum amount of loss is the unrealized appreciation of unsettled when-issued transactions.

TBA Commitments:TBA commitments are forward agreements for the purchase or sale of mortgage-backed securities for a fixed price, with payment and delivery on an agreed upon future settlement date. The specific securities to be delivered are not identified at the trade date. However, delivered securities must meet specified terms, including issuer, rate and mortgage terms. When entering into TBA commitments, the Master Portfolio may take possession of or deliver the underlying mortgage-backed securities but can extend the settlement or roll the transaction. TBA commitments involve a risk of loss if the value of the security to be purchased or sold declines or increases, respectively, prior to settlement date.

In order to better define contractual rights and to secure rights that will help the Master Portfolio mitigate its counterparty risk, TBA commitments may be entered into by the Master Portfolio under Master Securities Forward Transaction Agreements (each, an “MSFTA”). An MSFTA typically contains, among other things, collateral posting terms and netting provisions in the event of default and/or termination event. The collateral requirements are typically calculated by netting themark-to-market amount for each transaction under such agreement and comparing that amount to the value of the collateral currently pledged by the Master Portfolio and the counterparty. Cash collateral that has been pledged to cover the obligations of the Master Portfolio and cash collateral received from the counterparty, if any, is reported separately on the Statement of Assets and Liabilities as cash pledged as collateral for TBA commitments or cash received as collateral for TBA commitments, respectively.Non-cash collateral pledged by the Master Portfolio, if any, is noted in the Schedule of Investments. Typically, the Master Portfolio is permitted to sell,re-pledge or use the collateral it receives; however, the counterparty is not permitted to do so. To the extent amounts due to the Master Portfolio are not fully collateralized, contractually or otherwise, the Master Portfolio bears the risk of loss from counterpartynon-performance.

Mortgage Dollar Roll Transactions: The Master Portfolio may sell TBA mortgage-backed securities and simultaneously contract to repurchase substantially similar (i.e., same type, coupon and maturity) securities on a specific future date at an agreed upon price. During the period between the sale and repurchase, the Master Portfolio is not entitled to receive interest and principal payments on the securities sold. Mortgage dollar roll transactions are treated as purchases and sales and realizes gains and losses on these transactions. Mortgage dollar rolls involve the risk that the market value of the securities that the Master Portfolio is required to purchase may decline below the agreed upon repurchase price of those securities.

Securities Lending:The Master Portfolio may lend its securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the Master Portfolio collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by the Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the Master Portfolio and any additional required collateral is delivered to the Master Portfolio, or excess collateral returned by the Master Portfolio, on the next business day. During the term of the loan, the Master Portfolio is entitled to all distributions made on or in respect of the loaned securities, but does not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as corporate bonds in the Master Portfolio’s Schedule of Investments, and the value of any related collateral are shown separately in the Statement of Assets and Liabilities as a component of investments at value-unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedule of Investments.

66 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

Securities lending transactions are entered into by the Master Portfolio under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the Master Portfolio, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and the Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the Master Portfolio’s securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
Bank of America N.A.	$	199,629,398	$	(199,629,398	)	$	—
Barclays Bank PLC		11,556,296		(11,556,296	)		—
Barclays Capital,Inc.		6,018,536		(6,018,536	)		—
BMO Capital Markets		1,667,172		(1,667,172	)		—
BNP Paribas Prime Brokerage International Limited		11,869,476		(11,869,476	)		—
Citadel Clearing LLC		3,852,957		(3,852,957	)		—
Citigroup Global Markets,Inc.		719,588,220		(719,588,220	)		—
Credit Suisse Securities (USA) LLC		20,200,406		(20,200,406	)		—
Deutsche Bank Securities,Inc.		59,108,691		(59,108,691	)		—
Goldman Sachs & Co.		121,446,639		(121,446,639	)		—
HSBC PLC		12,543,744		(12,543,744	)		—
Jefferies LLC		1,400,575		(1,400,575	)		—
Morgan Stanley & Co. LLC		86,716,448		(86,716,448	)		—
Natwest Markets Securities,Inc.		2,027,195		(2,027,195	)		—
Nomura Securities International,Inc.		28,491,978		(28,491,978	)		—
RBC Capital Markets LLC		81,334,443		(81,334,443	)		—
Scotia Capital (USA), Inc.		9,557,496		(9,557,496	)		—
SG Americas Securities LLC		293,469		(293,469	)		—
State Street Bank & Trust Co.		732,035		(732,035	)		—
TD Prime Services LLC		203,078		(203,078	)		—
UBS AG		3,445,078		(3,445,078	)		—
UBS Securities LLC		217,036		(217,036	)		—
Wells Fargo Securities LLC		149,098,142		(149,098,142	)		—
	$	1,530,998,508	$	(1,530,998,508	)	$	—

^(a) Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by the Master Portfolio is disclosed in the Master Portfolio’s Statement of Assets and Liabilities.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the Master Portfolio benefits from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”). BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. The Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the Master Portfolio.

5. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the Master Portfolio, entered into an Investment Advisory Agreement with the Manager, the Master Portfolio’s investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory and administrative services. The Manager is responsible for the management of the Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Master Portfolio.

For such services, the Master Portfolio pays the Manager a monthly fee at an annual rate equal to 0.04% of the average daily value of the Master Portfolio’s net assets.

Administration: MIP, on behalf of the Master Portfolio, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the Master Portfolio’s ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Master Portfolio. BAL is entitled to receive for these administrative services an annual fee based on the average daily net assets of the Master Portfolio.

BAL is not entitled to compensation for providing administrative services to the Master Portfolio, for so long as BAL (or an affiliate) is entitled to compensation for providing administrative services to corresponding feeder funds that invest substantially all of their assets in the Master Portfolio, or BAL (or an affiliate) receives investment advisory fees from the Master Portfolio.

NOTESTO FINANCIAL STATEMENTS 67

Notes to Financial Statements  (continued)

Expense Waivers and Reimbursements:The fees and expenses of the Master Portfolio’s trustees who are not “interested persons” of Master Portfolio, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Master Portfolio’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Master Portfolio. BAL and BFA, as applicable, have contractually agreed to reimburse the Master Portfolio or provide an offsetting credit against the management fees paid by the Master Portfolio in an amount equal to these independent expenses through April 30, 2020. For the year ended December 31, 2019, the amount waived and/or reimbursed was $195,531.

The Manager contractually agreed to waive its investment advisory fees by the amount of investment advisory fees the Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the amounts waived were $486,466.

The Manager has contractually agreed to waive its investment advisory fee with respect to any portion of the Master Portfolio’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through April 30, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees of MIP or by a vote of a majority of the outstanding voting securities of the Master Portfolio. For the year ended December 31, 2019, there were no fees waived and/or reimbursed by the Manager pursuant to this arrangement.

Securities Lending: The U.S. Securities and Exchange Commission (“SEC”) has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The Master Portfolio is responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the Master Portfolio bears to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a 90 day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, the Master Portfolio retains 82% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, the Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 85% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Statement of Operations. For the year ended December 31, 2019, the Master Portfolio paid BTC $657,316 for securities lending agent services.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, the Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Master Portfolio’s investment policies and restrictions. The Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of the Master Portfolio are directors and/or officers of BlackRock or its affiliates.

Other Transactions:During the year ended December 31, 2019, the Master Portfolio received a reimbursement of $529,200 from an affiliate, which is included in Other income — affiliated in the Statement of Operations, related to an operating event.

The Master Portfolio may purchase securities from, or sell securities to, an affiliated fund provided the affiliation is due solely to having a common investment adviser, common officers, or common directors. For the year ended December 31, 2019, the purchase and sale transactions and any net realized gains (losses) with affiliated funds in compliance with Rule17a-7 under the 1940 Act were as follows:

Purchases		Sales		Net Realized Gain (Loss)
$	10,667,131	$	2,306,302	$	(66,390	)

68 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

6. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments, including paydowns, TBA transactions, mortgage dollar rolls and excluding short-term securities andin-kind redemptions, were as follows:

	Purchases		Sales
Non-U.S. Government Securities	$	15,698,757,501	$	14,462,697,496	*
U.S. Government Securities.		2,268,349,311		962,349,245

* Includes paydowns.

For the year ended December 31, 2019, purchases and sales related to mortgage dollar rolls were $5,988,007,949 and $5,989,914,092 respectively.

7. INCOME TAX INFORMATION

The Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

As of December 31, 2019, gross unrealized appreciation and depreciation for investments based on cost for U.S. federal income tax purposes were as follows:

Tax cost	$	13,155,837,125
Gross unrealized appreciation	$	416,144,290
Gross unrealized depreciation		(13,968,535	)
Net unrealized appreciation	$	402,175,755

8. BANK BORROWINGS

MIP, on behalf of the Master Portfolio, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the Master Portfolio may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the Master Portfolio, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statement of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the Master Portfolio did not borrow under the credit agreement.

9. PRINCIPAL RISKS

Many municipalities insure repayment of their bonds, which may reduce the potential for loss due to credit risk. The market value of these bonds may fluctuate for other reasons, including market perception of the value of such insurance, and there is no guarantee that the insurer will meet its obligation.

Inventories of municipal bonds held by brokers and dealers may decrease, which would lessen their ability to make a market in these securities. Such a reduction in market making capacity could potentially decrease the Master Portfolio’s ability to buy or sell bonds. As a result, the Master Portfolio may sell a security at a lower price, sell other securities to raise cash, or give up an investment opportunity, any of which could have a negative impact on performance. If the Master Portfolio needed to sell large blocks of bonds, those sales could further reduce the bonds’ prices and impact performance.

In the normal course of business, the Master Portfolio invests in securities or other instruments and may enter into certain transactions, and such activities subject the Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. The Master Portfolio’s prospectus provides details of the risks to which the Master Portfolio is subject.

NOTESTO FINANCIAL STATEMENTS 69

Notes to Financial Statements  (continued)

The Master Portfolio may be exposed to prepayment risk, which is the risk that borrowers may exercise their option to prepay principal earlier than scheduled during periods of declining interest rates, which would force the Master Portfolio to reinvest in lower yielding securities. The Master Portfolio may also be exposed to reinvestment risk, which is the risk that income from the Master Portfolio’s portfolio will decline if the Master Portfolio invests the proceeds from matured, traded or called fixed-income securities at market interest rates that are below the Master Portfolio portfolio’s current earnings rate.

The Master Portfolio may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Counterparty Credit Risk:The Master Portfolio may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolio manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Master Portfolio to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolio’s exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Master Portfolio.

Concentration Risk:The Master Portfolio invests a significant portion of its assets in fixed-income securities and/or uses derivatives tied to the fixed-income markets. Changes in market interest rates or economic conditions may affect the value and/or liquidity of such investments. Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall and decrease as interest rates rise. The Master Portfolio may be subject to a greater risk of rising interest rates due to the current period of historically low rates.

The Master Portfolio invests a significant portion of its assets in securities backed by commercial or residential mortgage loans or in issuers that hold mortgage and other asset-backed securities. Investment percentages in these securities are presented in the Schedule of Investments. Changes in economic conditions, including delinquencies and/or defaults on assets underlying these securities, can affect the value, income and/or liquidity of such positions.

10. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolio through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

70 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm U.S. Total Bond Index Master Portfolio

To the Board of Trustees of

Master Investment Portfolio and Investors of U.S. Total Bond Index Master Portfolio

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of U.S. Total Bond Index Master Portfolio (one of the series constituting Master Investment Portfolio, referred to hereafter as the “Master Portfolio”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Master Portfolio as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Master Portfolio’s management. Our responsibility is to express an opinion on the Master Portfolio’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolio in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING  FIRM 71

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of BlackRock Funds III and MIP, on behalf of iShares U.S. Aggregate Bond Index Fund and U.S. Total Bond Index Master Portfolio, respectively, met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions: During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements: The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

72 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director and non-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

TRUSTEEAND OFFICER INFORMATION 73

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcasting not-for-profit) since 2001; Chair, Basic Health International (non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director, Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

74 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees; Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015); President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on a case-by-case basis, as appropriate.
(c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015.
(d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Trust/MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex.
(e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

TRUSTEEAND OFFICER INFORMATION 75

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016; Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for the BFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.
(b) Officers of the Trust/MIP serve at the pleasure of the Board.

Further information about the Trust’s/MIP’s Trustees and Officers is available in the Trust’s/MIP’s Statement of Additional Information, which can be obtained without charge by calling (800) 441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Trust/MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Trust/MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of the Trust/MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Distributor

BlackRock Investments, LLC

New York, NY 10022

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of the Trust/MIP

400 Howard Street

San Francisco, CA 94105

76 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information

General Information

Householding

The Fund will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Fund at(800) 441-7762.

Availability of Quarterly Schedule of Investments

The Fund/Master Portfolio file their complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to their reports on Form N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information onForm N-Q. The Fund’s/Master Portfolio’s Forms N-PORT and N-Q are available on the SEC’s website at sec.gov. The Fund’s/Master Portfolio’s Form N-Q may also be obtained upon request and without charge by calling(800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Fund/Master Portfolio use to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling (800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Fund/Master Portfolio voted proxies relating to securities held in the Fund’s/Master Portfolio’s portfolio during the most recent 12-month period ended June 30 is available upon request and without charge (1) atblackrock.com or by calling (800) 441-7762 and (2) on the SEC’s website at sec.gov.

BlackRock’s Mutual Fund Family

BlackRock offers a diverse lineup of open-end mutual funds crossing all investment styles and managed by experts in equity, fixed income and tax-exempt investing. Visitblackrock.comfor more information.

Shareholder Privileges

Account Information

Call us at (800) 441-7762 from 8:00 AM to 6:00 PM ET on any business day to get information about your account balances, recent transactions and share prices. You can also visitblackrock.com for more information.

Automatic Investment Plans

Investor class shareholders who want to invest regularly can arrange to have $50 or more automatically deducted from their checking or savings account and invested in any of the BlackRock funds.

Systematic Withdrawal Plans

Investor class shareholders can establish a systematic withdrawal plan and receive periodic payments of $50 or more from their BlackRock funds, as long as their account balance is at least $10,000.

Retirement Plans

Shareholders may make investments in conjunction with Traditional, Rollover, Roth, Coverdell, Simple IRAs, SEP IRAs and 403(b) Plans.

ADDITIONAL INFORMATION 77

Additional Information  (continued)

BlackRock Privacy Principles

BlackRock is committed to maintaining the privacy of its current and former fund investors and individual clients (collectively, “Clients”) and to safeguarding their non-public personal information. The following information is provided to help you understand what personal information BlackRock collects, how we protect that information and why in certain cases we share such information with select parties.

If you are located in a jurisdiction where specific laws, rules or regulations require BlackRock to provide you with additional or different privacy-related rights beyond what is set forth below, then BlackRock will comply with those specific laws, rules or regulations.

BlackRock obtains or verifies personal non-public information from and about you from different sources, including the following: (i) information we receive from you or, if applicable, your financial intermediary, on applications, forms or other documents; (ii) information about your transactions with us, our affiliates, or others; (iii) information we receive from a consumer reporting agency; and (iv) from visits to our websites.

BlackRock does not sell or disclose to non-affiliated third parties any non-public personal information about its Clients, except as permitted by law or as is necessary to respond to regulatory requests or to service Client accounts. These non-affiliated third parties are required to protect the confidentiality and security of this information and to use it only for its intended purpose.

We may share information with our affiliates to service your account or to provide you with information about other BlackRock products or services that may be of interest to you. In addition, BlackRock restricts access to non-public personal information about its Clients to those BlackRock employees with a legitimate business need for the information. BlackRock maintains physical, electronic and procedural safeguards that are designed to protect the non-public personal information of its Clients, including procedures relating to the proper storage and disposal of such information.

Glossary of Terms Used in this Report

Portfolio Abbreviations
AGM	Assured Guaranty Municipal Corp.
ARB	Airport Revenue Bonds
EDA	Economic Development Authority
GO	General Obligation Bonds
LIBOR	London Interbank Offered Rate
NPFGC	National Public Finance Guarantee Corp.
RB	Revenue Bonds
S&P	Standard & Poor’s

78 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Want to know more?

blackrock.com    |    877-275-1255 (1-877-ASK-1BLK)

This report is intended for current holders. It is not authorized for use as an offer of sale or a solicitation of an offer to buy shares of the Fund unless preceded or accompanied by the Fund’s current prospectus. Past performance results shown in this report should not be considered a representation of future performance. Investment returns and principal value of shares will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Statements and other information herein are as dated and are subject to change.

USTB-12/19-AR

Portfolio Information  as of December 31, 2019 Active Stock Master Portfolio

TEN LARGEST HOLDINGS

Security	Percent of Net Assets
Apple, Inc.		2	%
Microsoft Corp.		2
Alibaba Group Holding Ltd. — ADR		1
Amazon.com, Inc.		1
Taiwan Semiconductor Manufacturing Co. Ltd.		1
Tencent Holdings Ltd.		1
Facebook, Inc.		1
Johnson & Johnson		1
Samsung Electronics Co. Ltd.		1
Mastercard, Inc.		1

SECTOR ALLOCATION

Sector	Percent of Net Assets
Information Technology		16	%
Financials		14
Health Care		12
Consumer Discretionary		10
Industrials		10
Communication Services		6
Consumer Staples		6
Materials		5
Energy		4
Real Estate		4
Utilities		2
Short-Term Securities		15
Liabilities in Excess of Other Assets		(4	)

For Active Stock Master Portfolio (the “Master Portfolio”) compliance purposes, the Master Portfolio’s sector classifications refer to one or more of the sector sub-classifications used by one or more widely recognized market indexes or ratings group indexes, and/or as defined by the investment adviser. These definitions may not apply for purposes of this report, which may combine such sector sub-classifications for reporting ease.

Derivative Financial Instruments

The Master Portfolio may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The Master Portfolio’s successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation the Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The Master Portfolio’s investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.

PORTFOLIO INFORMATION / DERIVATIVE FINANCIAL INSTRUMENTS 1

Schedule of Investments December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Common Stocks — 87.4%
Aerospace & Defense — 0.8%
AAR Corp.		1,912	$	86,231
Aerojet Rocketdyne Holdings, Inc.(a)(b)		1,246		56,892
Arconic, Inc.		5,074		156,127
Boeing Co.		496		161,577
Curtiss-Wright Corp.		513		72,277
Ducommun, Inc.(a)		1,147		57,958
Hanwha Aerospace Co. Ltd.(a)		992		30,007
HEICO Corp.(b)		1,945		222,022
HEICO Corp., Class A		1,443		129,192
Hexcel Corp.(b)		1,605		117,663
Lockheed Martin Corp.		3,691		1,437,202
Meggitt PLC		627		5,461
Mercury Systems, Inc.(a)(b)		1,039		71,805
MTU Aero Engines AG		36		10,257
Northrop Grumman Corp.		1,007		346,378
Parsons Corp.(a)(b)		461		19,030
Raytheon Co.		1,815		398,828
Spirit AeroSystems Holdings, Inc., Class A		956		69,673
Teledyne Technologies, Inc.(a)(b)		1,586		549,612
TransDigm Group, Inc.(b)		388		217,280
Wesco Aircraft Holdings, Inc.(a)		2,940		32,399
				4,247,871
Air Freight & Logistics — 0.6%
C.H. Robinson Worldwide, Inc.(b)		3,430		268,226
Deutsche Post AG, Registered Shares		2,215		84,224
DSV PANALPINA A/S		595		68,576
Echo Global Logistics, Inc.(a)(b)		4,359		90,231
Expeditors International of Washington, Inc.		1,672		130,449
FedEx Corp.		3,430		518,650
Hub Group, Inc., Class A(a)(b)		8,291		425,245
Hyundai Glovis Co. Ltd.		279		34,425
Radiant Logistics, Inc.(a)		13,114		73,045
United Parcel Service, Inc., Class B		7,552		884,037
XPO Logistics, Inc.(a)(b)		3,138		250,099
				2,827,207
Airlines — 0.8%
Alaska Air Group, Inc.		1,721		116,598
American Airlines Group, Inc.		19,942		571,937
Copa Holdings SA, Class A		142		15,347
Delta Air Lines, Inc.		19,594		1,145,857
Deutsche Lufthansa AG, Registered Shares		978		18,002
Southwest Airlines Co.		17,353		936,715
Spirit Airlines, Inc.(a)(b)		10,081		406,365
United Airlines Holdings, Inc.(a)		11,511		1,014,004
				4,224,825
Auto Components — 0.5%
Aisin Seiki Co. Ltd.		1,000		37,040
American Axle & Manufacturing Holdings, Inc.(a)(b)		7,040		75,750
Aptiv PLC		2,263		214,917
Autoliv, Inc.		1,195		100,870
BorgWarner, Inc.		2,097		90,968
Cie Generale des Etablissements Michelin SCA		713		87,741
Continental AG		53		6,849
Cooper-Standard Holdings, Inc.(a)		2,053		68,077
Dana, Inc.		22,284		405,569
Denso Corp.		1,700		76,776
Gentex Corp.		1,529		44,310
Goodyear Tire & Rubber Co.		10,338		160,808
Koito Manufacturing Co. Ltd.		600		27,784
LCI Industries		5,286		566,289
Lear Corp.		37		5,076

Security	Shares		Value
Auto Components (continued)
Standard Motor Products, Inc.		1,390	$	73,976
Stanley Electric Co. Ltd.		1,400		40,434
Sumitomo Electric Industries Ltd.		7,400		111,134
Tenneco, Inc., Class A		12,138		159,008
Toyota Industries Corp.		500		28,770
Visteon Corp.(a)		1,269		109,883
				2,492,029
Automobiles — 0.7%
BAIC Motor Corp. Ltd., Class H(c)		74,500		42,333
Bayerische Motoren Werke AG		783		64,132
Daimler AG, Registered Shares		534		29,522
Ferrari NV		179		29,720
Fiat Chrysler Automobiles NV		871		12,914
Ford Motor Co.		51,140		475,602
Ford Otomotiv Sanayi AS		16,064		191,262
General Motors Co.		17,028		623,225
Harley-Davidson, Inc.(b)		1,737		64,599
Honda Motor Co. Ltd.		2,200		62,263
Hyundai Motor Co.		6,380		664,521
Kia Motors Corp.		8,988		343,256
Peugeot SA		844		20,321
Renault SA		623		29,585
Suzuki Motor Corp.		1,100		45,916
Tesla, Inc.(a)(b)		1,434		599,885
Toyota Motor Corp.		4,000		281,846
Winnebago Industries, Inc.(b)		573		30,358
				3,611,260
Banks — 6.6%
ABN AMRO Group NV CVA(c)		288		5,249
AIB Group PLC		1,393		4,853
Akbank TAS(a)		53,248		72,530
Al Rajhi Bank		33,536		584,807
Alinma Bank		45,334		306,341
Ameris Bancorp(b)		333		14,166
AMMB Holdings Bhd		47,400		45,336
Australia & New Zealand Banking Group Ltd.		4,879		84,143
Banco Bilbao Vizcaya Argentaria SA		11,406		64,037
Banco de Sabadell SA		2,141		2,507
Banco do Brasil SA		9,800		128,679
Banco Santander Brasil SA		3,100		38,161
Banco Santander SA		31,805		133,350
Bancolombia SA — ADR		13,858		759,280
Bancorp, Inc.(a)		11,436		148,325
BankAl-Jazira		10,368		41,605
Bank Hapoalim BM		1,940		16,111
Bank LeumiLe-Israel BM		2,554		18,626
Bank Mandiri Persero Tbk PT		631,100		348,723
Bank of America Corp.		53,487		1,883,812
Bank of Beijing Co. Ltd., Class A		215,600		176,062
Bank of Commerce Holdings		4,494		51,996
Bank of East Asia Ltd.(b)		2,200		4,912
Bank of Guiyang Co. Ltd.		84,600		116,308
Bank of Ireland Group PLC		1,656		9,114
Bank of Jiangsu Co. Ltd., Class A		167,298		174,210
Bank of Nanjing Co. Ltd., Class A		85,566		107,912
Bank of Shanghai Co. Ltd., Class A		45,296		61,823
Bank OZK		1,713		52,255
Bank Polska Kasa Opieki SA		6,581		174,156
Bank7 Corp.		10		190
BankFinancial Corp.		1,975		25,833
Banner Corp.		8,722		493,578
Banque Saudi Fransi		3,326		33,605
Barclays PLC		29,492		70,323

2 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Banks (continued)
BNP Paribas SA		1,937	$	115,132
BOC Hong Kong Holdings Ltd.		11,000		38,186
Cadence BanCorp(b)		11,287		204,633
CaixaBank SA		6,139		19,332
Capital City Bank Group, Inc.		2,895		88,297
Capstar Financial Holdings, Inc.		1,368		22,777
Cathay General Bancorp(b)		24,173		919,783
Central Pacific Financial Corp.		18,926		559,831
Chiba Bank Ltd. (The)		900		5,175
China CITIC Bank Corp. Ltd., Class A		62,596		55,521
China CITIC Bank Corp. Ltd., Class H		202,000		121,120
China Construction Bank Corp., Class H		616,000		534,097
China Everbright Bank Co. Ltd., Class A		348,300		220,833
China Merchants Bank Co. Ltd., Class H		16,500		84,829
China Minsheng Banking Corp. Ltd., Class A(a)		169,900		154,099
CIMB Group Holdings Bhd		475,600		599,027
CIT Group, Inc.		5,580		254,615
Citigroup, Inc.		6,077		485,491
Citizens Financial Group, Inc.		2,008		81,545
Coastal Financial Corp./WA(a)		267		4,397
Comerica, Inc.		262		18,798
Commonwealth Bank of Australia		3,313		185,852
Credicorp Ltd.		831		177,111
Credit Agricole SA		1,961		28,535
CTBC Financial Holding Co. Ltd.		557,000		416,715
Cullen/Frost Bankers, Inc.(b)		2,741		268,015
Danske Bank A/S		429		6,940
DBS Group Holdings Ltd.		3,000		57,844
DNB ASA		934		17,478
Dubai Islamic Bank PJSC		32,718		49,107
East West Bancorp, Inc.		3,050		148,535
Erste Group Bank AG(a)		368		13,823
First Abu Dhabi Bank PJSC		28,253		116,824
First BanCorp, Puerto Rico		1,403		14,858
First Citizens BancShares, Inc., Class A		52		27,675
First Commonwealth Financial Corp.		4,945		71,752
First Financial Corp.		1,377		62,956
First Financial Northwest, Inc.		18,667		278,885
First Horizon National Corp.		16,351		270,773
First Midwest Bancorp, Inc.(b)		2,099		48,403
First Savings Financial Group, Inc.(b)		453		30,396
First United Corp.		982		23,656
Glacier Bancorp, Inc.(b)		3,633		167,082
Hang Seng Bank Ltd.(b)		2,400		49,608
HBT Financial, Inc.(a)		12,974		246,376
HDFC Bank Ltd.		45,434		810,704
HDFC Bank Ltd. — ADR		10,362		656,640
Home BancShares, Inc.(b)		23,474		461,499
Hong Leong Bank Bhd		16,600		70,245
HSBC Holdings PLC		43,062		337,108
Iberiabank Corp.		2,882		215,660
Independent Bank Group, Inc.		8,774		486,431
Industrial & Commercial Bank of China Ltd., Class A		126,000		106,516
Industrial & Commercial Bank of China Ltd., Class H		111,000		85,640
ING Groep NV		6,710		80,670
Intesa Sanpaolo SpA		25,629		67,512
Investors Bancorp, Inc.		11,646		138,762
Israel Discount Bank Ltd., Series A		738		3,427
Japan Post Bank Co. Ltd.		12,000		115,137
JPMorgan Chase & Co.(b)		18,954		2,642,188
Karnataka Bank Ltd.		48,343		48,830
KB Financial Group, Inc.		7,343		302,517
KBC Group NV		358		26,991
KeyCorp		615		12,448

Security	Shares		Value
Banks (continued)
Kotak Mahindra Bank Ltd.		14,966	$	353,231
Lakeland Bancorp, Inc.		6,566		114,117
M&T Bank Corp.		132		22,407
Macatawa Bank Corp.		505		5,621
Mediobanca Banca di Credito Finanziario SpA		1,069		11,770
Mercantile Bank Corp.		4,790		174,691
Mitsubishi UFJ Financial Group, Inc.		33,400		180,572
Mizuho Financial Group, Inc.		64,300		99,049
National Australia Bank Ltd.		4,841		83,769
National Bank Holdings Corp., Class A		2,352		82,837
National Commercial Bank		36,998		485,719
Nedbank Group Ltd.		16,668		255,217
Nordea Bank Abp		4,428		35,823
Opus Bank		1,160		30,009
Oversea-Chinese Banking Corp. Ltd.		5,400		44,175
Pacific Mercantile Bancorp(a)		25,243		204,973
Powszechna Kasa Oszczednosci Bank Polski SA		86,780		787,845
Regional SAB de CV		20,200		113,406
Republic Bancorp, Inc., Class A		7,218		337,802
Republic First Bancorp, Inc.(a)(b)		67,050		280,269
Resona Holdings, Inc.		3,500		15,255
RHB Capital Bhd		140,300		198,248
Riyad Bank		35,129		224,835
Royal Bank of Scotland Group PLC		8,273		26,539
Samba Financial Group		10,249		88,672
Sandy Spring Bancorp, Inc.		28,218		1,068,898
Saudi British Bank		3,811		35,241
Shanghai Pudong Development Bank Co. Ltd., Class A		49,300		87,681
Shinhan Financial Group Co. Ltd.		8,654		324,463
Shizuoka Bank Ltd.		700		5,207
Sierra Bancorp(b)		9,097		264,905
Skandinaviska Enskilda Banken AB, Class A		523		4,918
Societe Generale SA		1,313		45,821
South Plains Financial, Inc.		6,038		126,013
South State Corp.		3,361		291,567
Standard Bank Group Ltd.		59,220		712,296
Standard Chartered PLC		4,776		45,005
Sumitomo Mitsui Financial Group, Inc.		4,100		151,435
Sumitomo Mitsui Trust Holdings, Inc.		500		19,765
Svenska Handelsbanken AB, Class A		1,244		13,398
Swedbank AB, Class A		285		4,237
Synovus Financial Corp.		7,303		286,278
TCF Financial Corp.		817		38,236
TriState Capital Holdings, Inc.(a)(b)		43,917		1,147,112
Truist Financial Corp.		6,444		362,926
Turkiye Garanti Bankasi AS(a)		186,241		348,796
U.S. Bancorp		8,658		513,333
UniCredit SpA		3,461		50,589
United Community Banks, Inc.		33,577		1,036,858
United Overseas Bank Ltd.		2,100		41,300
Univest Financial Corp.		4,217		112,931
Wells Fargo & Co.(b)		24,292		1,306,910
WesBanco, Inc.		143		5,404
Westpac Banking Corp.		5,937		101,385
Wintrust Financial Corp.		7,010		497,009
Woori Financial Group, Inc.		3,462		34,662
Zions Bancorp. NA		873		45,326
				33,675,316
Beverages — 1.6%
Anadolu Efes Biracilik Ve Malt Sanayii AS		28,678		111,260
Anheuser-Busch InBev SA		1,735		142,097
Asahi Group Holdings Ltd.		800		36,496
Brown-Forman Corp., Class B(b)		2,236		151,154
Budweiser Brewing Co. APAC Ltd.(a)(c)		7,200		24,301

SCHEDULE OF INVESTMENTS 3

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Beverages (continued)
Carlsberg A/S, Class B		23	$	3,432
Coca-Cola Co.		25,860		1,431,351
Coca-Cola European Partners PLC		6,169		313,879
Coca-Cola Femsa SAB de C.V., ADR		4,212		255,331
Coca-Cola Femsa SAB de CV		38,800		235,745
Coca-Cola HBC AG(a)		777		26,410
Constellation Brands, Inc., Class A		1,282		243,260
Davide Campari-Milano SpA		1,000		9,137
Diageo PLC		5,526		232,847
Fomento Economico Mexicano SAB de CV		92,000		869,371
Fraser & Neave Holdings BHD		10,200		86,876
Heineken Holding NV		1,004		97,581
Heineken NV		325		34,687
Kirin Holdings Co. Ltd.		1,700		37,105
Molson Coors Brewing Co., Class B(b)		3,064		165,150
Monster Beverage Corp.(a)		6,499		413,012
National Beverage Corp.(a)		4,785		244,131
PepsiCo, Inc.		12,467		1,703,865
Pernod Ricard SA		283		50,639
Shanxi Xinghuacun Fen Wine Factory Co. Ltd., Class A		16,863		217,502
Suntory Beverage & Food Ltd.		200		8,350
Wuliangye Yibin Co. Ltd., Class A		46,600		892,351
				8,037,320
Biotechnology — 3.3%
AbbVie, Inc.		13,028		1,153,499
ACADIA Pharmaceuticals, Inc.(a)(b)		8,123		347,502
Acceleron Pharma, Inc.(a)(b)		1,564		82,923
Agenus, Inc.(a)		45,478		185,095
Aimmune Therapeutics, Inc.(a)(b)		600		20,082
Akcea Therapeutics, Inc.(a)		645		10,926
Akero Therapeutics, Inc.(a)		1,213		26,923
Alder Biopharmaceuticals, Inc.(d)		3,943		3,470
Alector, Inc.(a)		801		13,801
Alexion Pharmaceuticals, Inc.(a)		1,731		187,208
Alnylam Pharmaceuticals, Inc.(a)(b)		309		35,588
Amgen, Inc.		4,135		996,824
Apellis Pharmaceuticals, Inc.(a)		5,217		159,745
Aptinyx, Inc.(a)		15,699		53,691
AquaBounty Technologies, Inc.(a)(b)		3		7
Arcus Biosciences, Inc.(a)(b)		24,198		244,400
Arrowhead Pharmaceuticals, Inc.(a)(b)		4,851		307,699
Atara Biotherapeutics, Inc.(a)		3,887		64,019
Athersys, Inc.(a)(b)		54,167		66,625
Audentes Therapeutics, Inc.(a)		2,010		120,278
BeiGene Ltd., ADR(a)		83		13,758
Beyondspring, Inc.(a)		672		10,416
Biocon Ltd.		77,216		317,721
BioCryst Pharmaceuticals, Inc.(a)		5,428		18,727
Biogen, Inc.(a)		1,363		404,443
Biohaven Pharmaceutical Holding Co. Ltd.(a)		1,357		73,875
BioMarin Pharmaceutical, Inc.(a)		200		16,910
Blueprint Medicines Corp.(a)		486		38,933
Calithera Biosciences, Inc.(a)(b)		21,066		120,287
Castle Biosciences, Inc.(a)(b)		1,050		36,089
Celltrion, Inc.(a)		871		135,777
ChemoCentryx, Inc.(a)		8,603		340,249
Chimerix, Inc.(a)		18,925		38,418
Coherus Biosciences, Inc.(a)(b)		15,034		270,687
Corvus Pharmaceuticals, Inc.(a)(b)		21,424		116,547
Crinetics Pharmaceuticals, Inc.(a)(b)		1,995		50,055
CSL Ltd.		868		168,290
CytomX Therapeutics, Inc.(a)		2,089		17,360
Deciphera Pharmaceuticals, Inc.(a)(b)		1,984		123,484
Denali Therapeutics, Inc.(a)(b)		6,803		118,508

Security	Shares		Value
Biotechnology (continued)
Eagle Pharmaceuticals, Inc.(a)(b)		2,477	$	148,818
Eiger Biopharmaceuticals, Inc.(a)		2,058		30,664
Emergent Biosolutions, Inc.(a)(b)		3,075		165,896
Enanta Pharmaceuticals, Inc.(a)(b)		3,700		228,586
Epizyme, Inc.(a)(b)		3,065		75,399
Exact Sciences Corp.(a)(b)		2,871		265,510
Exelixis, Inc.(a)(b)		4,683		82,514
Fate Therapeutics, Inc.(a)(b)		9,857		192,901
FibroGen, Inc.(a)(b)		4,926		211,276
Flexion Therapeutics, Inc.(a)(b)		4,562		94,433
Galapagos NV(a)		26		5,414
Genmab A/S(a)		97		21,573
Gilead Sciences, Inc.(b)		24,851		1,614,818
Global Blood Therapeutics, Inc.(a)(b)		3,675		292,126
Gossamer Bio, Inc.(a)(b)		3,404		53,205
Green Cross Corp.		1,156		132,015
Grifols SA		510		18,019
Hualan Biological Engineering, Inc., Class A		20,900		105,698
Immunomedics, Inc.(a)(b)		10,077		213,229
Incyte Corp.(a)		1,816		158,573
Insmed, Inc.(a)		8,999		214,896
Intellia Therapeutics, Inc.(a)(b)		6,798		99,727
Intercept Pharmaceuticals, Inc.(a)		2,852		353,420
Invitae Corp.(a)(b)		11,559		186,447
Ionis Pharmaceuticals, Inc.(a)		730		44,099
Ironwood Pharmaceuticals, Inc.(a)		19,339		257,402
Jounce Therapeutics, Inc.(a)		6,615		57,749
KalVista Pharmaceuticals, Inc.(a)(b)		1,067		19,003
Kezar Life Sciences, Inc.(a)		3,133		12,563
Kodiak Sciences, Inc.(a)		747		53,747
Ligand Pharmaceuticals, Inc.(a)(b)		2,977		310,471
MacroGenics, Inc.(a)		8,094		88,063
Medicines Co.(a)		3,065		260,341
Medy-Tox, Inc.		155		40,309
Mirati Therapeutics, Inc.(a)		787		101,413
Natera, Inc.(a)		9,359		315,305
Neurocrine Biosciences, Inc.(a)		191		20,531
OPKO Health, Inc.(a)		49,249		72,396
Portola Pharmaceuticals, Inc.(a)(b)		3,626		86,589
Precision BioSciences, Inc.(a)(b)		3,260		45,281
Principia Biopharma, Inc.(a)		1,837		100,631
Puma Biotechnology, Inc.(a)		5,073		44,389
Ra Pharmaceuticals, Inc.(a)(b)		1,921		90,153
Radius Health, Inc.(a)		969		19,535
Regeneron Pharmaceuticals, Inc.(a)		1,328		498,637
Replimune Group, Inc.(a)		3,054		43,825
Retrophin, Inc.(a)(b)		17,990		255,458
Rigel Pharmaceuticals, Inc.(a)		15,153		32,427
Sangamo Therapeutics, Inc.(a)(b)		6,487		54,296
Sarepta Therapeutics, Inc.(a)		169		21,808
Seattle Genetics, Inc.(a)(b)		347		39,648
Seegene, Inc.(a)		3,949		104,287
Seres Therapeutics, Inc.(a)		21,532		74,285
Spectrum Pharmaceuticals, Inc.(a)		9,826		35,767
Stemline Therapeutics, Inc.(a)(b)		1,297		13,787
Sutro Biopharma, Inc.(a)(b)		2,790		30,690
Turning Point Therapeutics, Inc.(a)		801		49,894
Ultragenyx Pharmaceutical, Inc.(a)(b)		6,605		282,100
United Therapeutics Corp.(a)		1,648		145,156
UNITY Biotechnology, Inc.(a)(b)		7,272		52,431
Vanda Pharmaceuticals, Inc.(a)		2,392		39,253
Veracyte, Inc.(a)		9,446		263,732
Vertex Pharmaceuticals, Inc.(a)(b)		3,313		725,381
X4 Pharmaceuticals, Inc.(a)		864		9,245

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Biotechnology (continued)
Xencor, Inc.(a)		1,614	$	55,505
Y-mAbs Therapeutics, Inc.(a)		3,589		112,156
				16,455,734
Building Products — 0.4%
Advanced Drainage Systems, Inc.		881		34,218
AGC, Inc.		1,000		35,758
Allegion PLC		7,117		886,351
Apogee Enterprises, Inc.		617		20,053
Assa Abloy AB, Class B		2,593		60,613
Builders FirstSource, Inc.(a)		19,059		484,289
Cie de Saint-Gobain		930		38,098
Continental Building Products, Inc.(a)		1,921		69,982
Daikin Industries Ltd.		600		84,654
Kingspan Group PLC		239		14,597
Resideo Technologies, Inc.(a)		3,470		41,397
TOTO Ltd.		600		25,336
Trex Co., Inc.(a)		1,789		160,795
Universal Forest Products, Inc.		5,824		277,805
				2,233,946
Capital Markets — 2.1%
3i Group PLC		2,306		33,556
Affiliated Managers Group, Inc.(b)		1,700		144,058
Ameriprise Financial, Inc.		255		42,478
Amundi SA(c)		258		20,288
Ares Management Corp., Class A		2,673		95,399
Artisan Partners Asset Management, Inc., Class A		2,389		77,213
ASX Ltd.		331		18,225
B3 SA — Brasil Bolsa Balcao		21,985		234,841
Bank of New York Mellon Corp.		7,004		352,511
Blackstone Group, Inc., Class A		1,613		90,231
Cboe Global Markets, Inc.		442		53,040
Charles Schwab Corp.(b)		11,911		566,487
China Merchants Securities Co. Ltd., Class A		71,400		188,004
CITIC Securities Co. Ltd., Class H(b)		16,500		37,644
CME Group, Inc.		3,258		653,946
Cohen & Steers, Inc.		3,079		193,238
Credit Suisse Group AG, Registered Shares(a)		5,656		76,456
Daiwa Securities Group, Inc.		2,600		13,126
Deutsche Bank AG, Registered Shares		2,138		16,566
Deutsche Boerse AG		626		98,165
Donnelley Financial Solutions, Inc.(a)(b)		9,716		101,727
E*Trade Financial Corp.		131		5,944
Everbright Securities Co. Ltd., Class A		29,000		54,719
Evercore, Inc., Class A(b)		1,195		89,338
FactSet Research Systems, Inc.(b)		1,754		470,598
Focus Financial Partners, Inc., Class A(a)		3,441		101,406
Franklin Resources, Inc.(b)		929		24,135
Goldman Sachs Group, Inc.		1,015		233,379
Guotai Junan Securities Co. Ltd., Class A		107,400		285,849
Hamilton Lane, Inc., Class A(b)		1,587		94,585
Hargreaves Lansdown PLC		487		12,492
Hong Kong Exchanges & Clearing Ltd.		2,000		64,975
Industrial Securities Co. Ltd., Class A		211,400		215,503
Intercontinental Exchange, Inc.		10,369		959,651
Invesco Ltd.		2,426		43,620
Japan Exchange Group, Inc.		1,600		28,168
Julius Baer Group Ltd.(a)		383		19,745
KKR & Co., Inc., Class A		1,110		32,379
London Stock Exchange Group PLC		700		71,940
Macquarie Group Ltd.		553		53,555
MarketAxess Holdings, Inc.		131		49,663
Moelis & Co., Class A(b)		10,549		336,724
Moody’s Corp.		1,956		464,374

Security	Shares		Value
Capital Markets (continued)
Morgan Stanley		19,504	$	997,045
MSCI, Inc.		227		58,607
Nasdaq, Inc.		758		81,182
Natixis SA		1,618		7,207
NH Investment & Securities Co. Ltd.		4		44
Nomura Holdings, Inc.		7,200		37,050
Northern Trust Corp.		528		56,095
Partners Group Holding AG		66		60,491
Pzena Investment Management, Inc., Class A		2,613		22,524
Raymond James Financial, Inc.		244		21,828
S&P Global, Inc.		3,735		1,019,842
Schroders PLC		213		9,405
SEI Investments Co.		148		9,691
St. James’s Place PLC		908		13,997
Standard Life Aberdeen PLC		4,158		18,090
State Street Corp.		1,144		90,490
Stifel Financial Corp.		8,577		520,195
T. Rowe Price Group, Inc.		752		91,624
TD Ameritrade Holding Corp.		4,362		216,791
UBS Group AG, Registered Shares(a)		9,228		116,452
Virtus Investment Partners, Inc.(b)		2,066		251,474
Westwood Holdings Group, Inc.(b)		1,999		59,210
				10,579,275
Chemicals — 1.7%
Air Liquide SA		461		65,356
Air Products & Chemicals, Inc.		2,450		575,725
Albemarle Corp.(b)		1,874		136,877
Asahi Kasei Corp.		1,700		19,088
Axalta Coating Systems Ltd.(a)		3,003		91,291
BASF SE		2,256		169,959
Celanese Corp.		1,841		226,664
CF Industries Holdings, Inc.		3,122		149,044
Clariant AG, Registered Shares(a)		1,271		28,405
Corteva, Inc.(a)		5,189		153,387
Daicel Corp.		800		7,648
Dow, Inc.(a)		4,085		223,572
DuPont de Nemours, Inc.		4,902		314,708
Eastman Chemical Co.		987		78,230
Ecolab, Inc.		4,588		885,438
EMS-Chemie Holding AG, Registered Shares		55		36,159
FMC Corp.		747		74,566
Givaudan SA, Registered Shares		8		25,064
Hanwha Chemical Corp.		6,484		105,409
Hitachi Chemical Co. Ltd.		900		37,706
Ingevity Corp.(a)		1,605		140,245
Innophos Holdings, Inc.		408		13,048
Innospec, Inc.		2,781		287,667
International Flavors & Fragrances, Inc.(b)		1,582		204,110
Israel Chemicals Ltd.		6,191		29,237
Koninklijke DSM NV		526		68,772
Kumho Petrochemical Co. Ltd.		2,905		194,277
Linde PLC		2,579		549,069
LyondellBasell Industries NV, Class A		2,049		193,589
Mitsui Chemicals, Inc.		600		14,616
Mosaic Co.		8,337		180,413
Nippon Paint Holdings Co. Ltd.		1,900		97,815
Nissan Chemical Corp.		200		8,376
Nitto Denko Corp.		2,000		112,456
Novozymes A/S, Class B		313		15,317
PhosAgro PJSC, — GDR		16,832		213,766
PolyOne Corp.		27,194		1,000,467
PPG Industries, Inc.		2,292		305,959
RPM International, Inc.(b)		1,450		111,302
ScottsMiracle-Gro Co.		867		92,058

SCHEDULE OF INVESTMENTS 5

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Chemicals (continued)
Sherwin-Williams Co.		1,703	$	993,769
Shin-Etsu Chemical Co. Ltd.		600		65,984
Sinopec Shanghai Petrochemical Co. Ltd., Class H		634,000		191,391
Sumitomo Chemical Co. Ltd.		15,900		72,195
Symrise AG		722		75,889
Teijin Ltd.		1,000		18,682
Toray Industries, Inc.		8,300		56,237
Tosoh Corp.		1,300		20,027
Westlake Chemical Corp.(b)		694		48,684
				8,779,713
Commercial Services & Supplies — 0.7%
ADT, Inc.(b)		1,964		15,575
ARC Document Solutions, Inc.(a)		26,658		37,055
Cintas Corp.		740		199,119
Copart, Inc.(a)		1,491		135,592
Country Garden Services Holdings Co. Ltd.		38,000		127,939
Ennis, Inc.		5,515		119,400
Healthcare Services Group, Inc.(b)		10,513		255,676
McGrath RentCorp		10,370		793,720
Mobile Mini, Inc.		15,390		583,435
Republic Services, Inc.		140		12,548
Shanghai M&G Stationery, Inc.		13,900		97,430
Steelcase, Inc., Class A(b)		33,962		694,862
Tetra Tech, Inc.		2,911		250,812
Viad Corp.		5,529		373,207
Waste Management, Inc.		481		54,815
Harsco Corp.(a)		2,315		53,268
SP Plus Corp.(a)		1,632		69,246
				3,873,699
Communications Equipment — 0.4%
Calix, Inc.(a)(b)		16,263		130,104
Ciena Corp.(a)(b)		25,088		1,071,007
Cisco Systems, Inc.		13,083		627,461
Sercomm Corp.		45,000		116,783
Tessco Technologies, Inc.		16,102		180,664
				2,126,019
Construction & Engineering — 0.9%
ACS Actividades de Construccion y Servicios SA		1,606		64,423
Bouygues SA		1,289		54,946
China Communications Services Corp. Ltd., Class H		170,000		123,927
China Railway Construction Corp. Ltd., Class H		71,500		78,308
China Railway Group Ltd., Class H		301,000		185,744
Comfort Systems USA, Inc.		16,969		845,905
Dycom Industries, Inc.(a)(b)		9,856		464,710
Eiffage SA		564		64,706
EMCOR Group, Inc.		649		56,009
Engineers India Ltd.		31,276		43,387
Fluor Corp.		5,713		107,861
Hyundai Engineering & Construction Co. Ltd.		1,986		72,448
IRB Infrastructure Developers Ltd.(a)		49,010		51,154
KEC International Ltd.		14,197		60,106
Larsen & Toubro Ltd.		21,431		389,840
Larsen & Toubro Ltd. — GDR		2,111		38,784
MasTec, Inc.(a)		10,591		679,519
MYR Group, Inc.(a)		3,935		128,242
Obayashi Corp.		2,300		25,545
Samsung Engineering Co. Ltd.(a)		10,961		181,144
Shimizu Corp.		1,100		11,206
Sino-Thai Engineering & Construction PCL		54,500		25,799
Taisei Corp.		300		12,426
Tekfen Holding AS		109,616		356,028
Vinci SA		1,997		222,413

Security	Shares		Value
Construction & Engineering (continued)
Voltas, Ltd.		8,094	$	74,805
				4,419,385
Construction Materials — 0.4%
Anhui Conch Cement Co. Ltd., Class A		34,700		273,376
Anhui Conch Cement Co. Ltd., Class H		125,000		910,766
Cemex SAB de CV CPO		329,510		123,387
CRH PLC(a)		1,169		46,887
Martin Marietta Materials, Inc.		508		142,057
Summit Materials, Inc., Class A(a)(b)		15,613		373,151
Vulcan Materials Co.		969		139,526
				2,009,150
Consumer Finance — 0.7%
Acom Co. Ltd.		3,400		15,426
Ally Financial, Inc.		11,636		355,596
American Express Co.(b)		6,949		865,081
Bajaj Finance Ltd.		4,462		264,854
Capital One Financial Corp.		5,885		605,625
Discover Financial Services		948		80,409
Elevate Credit, Inc.(a)		8,804		39,178
Enova International, Inc.(a)		8,665		208,480
FirstCash, Inc.(b)		4,918		396,538
Gentera SAB de CV		38,100		39,234
Green Dot Corp., Class A(a)		16,891		393,560
Regional Management Corp.(a)		4,047		121,532
Synchrony Financial		1,569		56,500
				3,442,013
Containers & Packaging — 0.0%
Packaging Corp. of America		168		18,814
Westrock Co.		4,112		176,446
				195,260
Distributors — 0.1%
Core-Mark Holding Co., Inc.		8,394		228,233
Pool Corp.(b)		181		38,440
Wuchan Zhongda Group Co. Ltd.		40,300		30,428
				297,101
Diversified Consumer Services — 0.4%
Chegg, Inc.(a)		5,286		200,392
H&R Block, Inc.		7,412		174,034
New Oriental Education & Technology Group, Inc. — ADR(a)		6,673		809,101
OneSpaWorld Holdings Ltd.(a)		3,601		60,641
Strategic Education, Inc.(b)		4,068		646,405
				1,890,573
Diversified Financial Services — 0.7%
AXA Equitable Holdings, Inc.		3,445		85,367
Ayala Corp.		6,535		101,222
Berkshire Hathaway, Inc., Class B(a)		8,421		1,907,356
Chailease Holding Co. Ltd.		106,613		491,468
Eurazeo SE		69		4,736
EXOR NV		403		31,245
FGL Holdings		7,646		81,430
FirstRand Ltd.		94,935		425,972
Groupe Bruxelles Lambert SA		681		71,860
Industrivarden AB, Class C		286		6,897
Investor AB, Class B		2,324		126,876
Kinnevik AB, Class B		414		10,145
L E Lundbergforetagen AB, B Shares		502		22,037
M&G PLC(a)		4,365		13,715
Metro Pacific Investments Corp.		626,000		43,015
Mitsubishi UFJ Lease & Finance Co. Ltd.		600		3,863
ORIX Corp.		3,800		62,971

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Diversified Financial Services (continued)
Pargesa Holding SA, Bearer Shares		285	$	23,678
Voya Financial, Inc.		426		25,977
Wendel SA		46		6,128
Yuanta Financial Holding Co. Ltd.		172,000		115,953
				3,661,911
Diversified Telecommunication Services — 1.0%
AT&T, Inc.		22,860		893,369
Bandwidth, Inc., Class A(a)		716		45,860
CenturyLink, Inc.		10,449		138,031
China Unicom Hong Kong Ltd.		758,000		713,748
Cogent Communications Holdings, Inc.		8,995		591,961
Hellenic Telecommunications Organization SA		4,764		76,256
IDT Corp., Class B(a)		8,437		60,831
KT Corp. — ADR(a)		39,616		459,546
Nippon Telegraph & Telephone Corp.		600		15,164
Ooma, Inc.(a)		10,104		133,676
Saudi Telecom Co.		14,518		393,937
Tata Communications Ltd.		16,541		91,988
Telekom Malaysia Bhd		130,300		121,741
Turk Telekomunikasyon AS(a)		55,862		69,166
Verizon Communications, Inc.		24,033		1,475,626
Vonage Holdings Corp.(a)		2,328		17,250
				5,298,150
Electric Utilities — 1.1%
Alliant Energy Corp.		2,856		156,280
CEZ AS		11,459		257,536
CPFL Energia SA		27,300		241,260
Edison International		2,220		167,410
El Paso Electric Co.		2,241		152,141
Electricite de France SA		1,572		17,541
Energa SA(a)		11		21
Evergy, Inc.		890		57,930
Eversource Energy		226		19,226
Exelon Corp.		5,239		238,846
Fortum OYJ		1,248		30,805
Iberdrola SA		21,323		219,746
IDACORP, Inc.(b)		11,345		1,211,646
Inter RAO UES PJSC		4,981,360		405,154
NextEra Energy, Inc.		2,106		509,989
Orsted A/S(c)		452		46,748
Pinnacle West Capital Corp.		2,008		180,579
PNM Resources, Inc.		872		44,219
Portland General Electric Co.		2,759		153,925
Red Electrica Corp. SA		276		5,561
Tenaga Nasional Bhd		60,400		195,908
Terna Rete Elettrica Nazionale SpA		2,423		16,205
Verbund AG		116		5,821
Xcel Energy, Inc.		16,567		1,051,839
				5,386,336
Electrical Equipment — 0.5%
ABB Ltd., Registered Shares		4,330		104,453
Amara Raja Batteries Ltd.		2,304		23,381
AMETEK, Inc.		5,520		550,565
Atkore International Group, Inc.(a)		7,260		293,740
AZZ, Inc.		225		10,339
Bharat Heavy Electricals Ltd.		110,950		67,569
Fuji Electric Co. Ltd.		500		15,189
Generac Holdings, Inc.(a)		3,063		308,107
Hubbell, Inc.		2,821		417,000
LSI Industries, Inc.		14,477		87,586
Mitsubishi Electric Corp.		8,600		117,095
Nidec Corp.		1,000		136,584
Schneider Electric SE		2,419		248,527

Security	Shares		Value
Electrical Equipment (continued)
Siemens Gamesa Renewable Energy SA		408	$	7,185
Vestas Wind Systems A/S		604		61,008
				2,448,328
Electronic Equipment, Instruments & Components — 1.4%
AAC Technologies Holdings, Inc.		9,500		82,935
Anixter International, Inc.(a)		1,683		155,004
Avnet, Inc.		2,993		127,023
CDW Corp.		4,472		638,781
Compeq Manufacturing Co. Ltd.		110,000		165,874
Corning, Inc.		538		15,661
Daktronics, Inc.		2,955		17,996
ePlus, Inc.(a)		684		57,654
Hirose Electric Co. Ltd.		400		51,133
Hitachi Ltd.		1,100		46,415
Hon Hai Precision Industry Co. Ltd.		450,000		1,365,081
Hon Hai Precision Industry Co. Ltd., — GDR		2,721		16,652
Insight Enterprises, Inc.(a)(b)		3,867		271,811
IPG Photonics Corp.(a)(b)		203		29,419
Keyence Corp.		200		70,228
Largan Precision Co. Ltd.		5,000		835,191
LG Innotek Co. Ltd.		1,389		167,417
Murata Manufacturing Co. Ltd.		2,000		123,097
National Instruments Corp.(b)		6,144		260,137
Omron Corp.		100		5,829
OSI Systems, Inc.(a)(b)		7,925		798,365
PC Connection, Inc.		9,284		461,044
Sanmina Corp.(a)		3,764		128,879
ScanSource, Inc.(a)		19,859		733,790
Sunny Optical Technology Group Co. Ltd.		10,400		180,192
TDK Corp.		800		89,903
Tech Data Corp.(a)		2,009		288,492
TPK Holding Co. Ltd.(a)		23,000		43,620
Unimicron Technology Corp.		70,000		98,634
				7,326,257
Energy Equipment & Services — 0.4%
Archrock, Inc.		37,420		375,697
Baker Hughes Co.		4,401		112,798
Exterran Corp.(a)(b)		4,864		38,085
Forum Energy Technologies, Inc.(a)		129,774		218,020
Halliburton Co.		5,402		132,187
Matrix Service Co.(a)		7,714		176,496
National Oilwell Varco, Inc.		3,544		88,777
Natural Gas Services Group, Inc.(a)(b)		4,228		51,835
Oceaneering International, Inc.(a)(b)		17,187		256,258
Oil States International, Inc.(a)(b)		2,154		35,132
Patterson-UTI Energy, Inc.(b)		8,708		91,434
ProPetro Holding Corp.(a)		5,360		60,300
Seadrill Ltd.(a)		4,489		11,402
TechnipFMC PLC		5,395		115,669
Tenaris SA		2,082		23,589
Transocean Ltd.(a)		13,908		95,687
				1,883,366
Entertainment — 0.7%
Activision Blizzard, Inc.		3,393		201,612
Bollore SA		2,022		8,836
Cinemark Holdings, Inc.		3,311		112,077
Electronic Arts, Inc.(a)		2,157		231,899
Glu Mobile, Inc.(a)(b)		13,000		78,650
HUYA, Inc., ADR(a)		4,086		73,344
IGG, Inc.(b)		91,000		67,201
Konami Holdings Corp.		100		4,109
Live Nation Entertainment, Inc.(a)		3,378		241,426
NCSoft Corp.		292		136,249

SCHEDULE OF INVESTMENTS 7

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Entertainment (continued)
NetEase, Inc. — ADR(b)		2,168	$	664,795
Netflix, Inc.(a)		761		246,237
Nexon Co. Ltd.(a)		800		10,612
Nintendo Co. Ltd.		200		79,992
Spotify Technology SA(a)		803		120,089
Take-Two Interactive Software, Inc.(a)(b)		2,048		250,737
UbiSoft Entertainment SA(a)		143		9,907
Walt Disney Co.		5,628		813,978
Zynga, Inc., Class A(a)		30,985		189,628
				3,541,378
Equity Real Estate Investment Trusts (REITs) — 3.0%
Acadia Realty Trust		9,246		239,749
Agree Realty Corp.		202		14,174
Alexandria Real Estate Equities, Inc.		601		97,110
American Tower Corp.		1,374		315,773
Armada Hoffler Properties, Inc.(b)		19,806		363,440
AvalonBay Communities, Inc.		417		87,445
Boston Properties, Inc.		1,924		265,243
Brandywine Realty Trust(b)		10,960		172,620
British Land Co. PLC		1,539		13,022
City Office REIT, Inc.		30,922		418,065
Covivio		78		8,858
Crown Castle International Corp.		1,243		176,692
Daiwa House REIT Investment Corp.		3		7,844
Dexus		1,867		15,369
DiamondRock Hospitality Co.		13,254		146,854
Digital Realty Trust, Inc.		440		52,686
EastGroup Properties, Inc.		11,431		1,516,551
Equinix, Inc.		230		134,251
Equity LifeStyle Properties, Inc.		127		8,939
Equity Residential		4,480		362,522
Essex Property Trust, Inc.		504		151,633
Extra Space Storage, Inc.		74		7,816
Fibra Uno Administracion SA de CV		41,000		63,514
First Industrial Realty Trust, Inc.		22,013		913,760
Four Corners Property Trust, Inc.(b)		36,485		1,028,512
Gecina SA		129		23,094
Goodman Group		2,792		26,237
GPT Group		3,313		13,050
Healthpeak Properties, Inc.		840		28,955
Hersha Hospitality Trust(b)		32,131		467,506
Host Hotels & Resorts, Inc.		8,983		166,635
ICADE		51		5,553
Invitation Homes, Inc.		11,414		342,078
Japan Prime Realty Investment Corp.		1		4,397
Japan Real Estate Investment Corp.		3		19,909
Japan Retail Fund Investment Corp.		4		8,608
Klepierre SA		342		13,011
Lamar Advertising Co., Class A(b)		5,215		465,491
Land Securities Group PLC		1,205		15,817
Link REIT		4,500		47,673
Mid-America Apartment Communities, Inc.		139		18,329
Mirvac Group		3,934		8,805
National Retail Properties, Inc.		3,327		178,394
National Storage Affiliates Trust(b)		10,634		357,515
NexPoint Residential Trust, Inc.		18,913		851,085
Nippon Building Fund, Inc.		4		29,321
Nippon Prologis REIT, Inc.		3		7,641
Nomura Real Estate Master Fund, Inc.		7		11,974
Park Hotels & Resorts, Inc.(b)		17,230		445,740
Plymouth Industrial REIT, Inc.		786		14,455
Prologis, Inc.		2,819		251,286
Public Storage		463		98,600
QTS Realty Trust, Inc., Class A		16,048		870,925

Security	Shares		Value
Equity Real Estate Investment Trusts (REITs) (continued)
Realty Income Corp.		792	$	58,315
Regency Centers Corp.		158		9,968
RLJ Lodging Trust(b)		62,139		1,101,103
Ryman Hospitality Properties, Inc.		6,879		596,134
SBA Communications Corp.		253		60,970
Scentre Group		9,095		24,477
Segro PLC		1,870		22,267
Simon Property Group, Inc.		6,070		904,187
SL Green Realty Corp.		359		32,985
STAG Industrial, Inc.		7,472		235,891
Stockland		4,079		13,235
Summit Hotel Properties, Inc.(b)		32,574		401,963
Sun Communities, Inc.		118		17,712
Sunstone Hotel Investors, Inc.		13,969		194,448
UDR, Inc.		1,014		47,354
United Urban Investment Corp.		5		9,390
Ventas, Inc.		856		49,425
Vicinity Centres		5,484		9,592
Welltower, Inc.(b)		1,263		103,288
Weyerhaeuser Co.		774		23,375
WP Carey, Inc.		167		13,367
Unibail-Rodamco-Westfield		237		37,391
				15,341,363
Food & Staples Retailing — 1.1%
Aeon Co. Ltd.		1,700		35,082
Carrefour SA		998		16,785
Coles Group Ltd.		1,300		13,533
Colruyt SA		1,059		55,213
Costco Wholesale Corp.		8,001		2,351,654
CP ALL PCL — NVDR		163,700		394,447
FamilyMart Co. Ltd.		400		9,580
ICA Gruppen AB		2,140		99,963
J. Sainsbury PLC		25,567		77,960
Koninklijke Ahold Delhaize NV		280		7,020
Kroger Co.(b)		8,897		257,924
METRO AG		2,017		32,456
Performance Food Group Co.(a)		11,103		571,582
Raia Drogasil SA		2,400		66,606
Seven & i Holdings Co. Ltd.		700		25,659
Spar Group Ltd.(b)		4,442		62,752
Sysco Corp.		4,435		379,370
Tesco PLC		27,887		94,248
Tsuruha Holdings, Inc.		100		12,840
Wal-Mart de Mexico SAB de CV		90,700		259,760
Walgreens Boots Alliance, Inc.		5,858		345,388
Walmart, Inc.		2,086		247,900
Weis Markets, Inc.(b)		874		35,388
WM Morrison Supermarkets PLC		23,724		62,787
Woolworths Group Ltd.		2,992		75,887
				5,591,784
Food Products — 1.6%
a2 Milk Co. Ltd.(a)		1,257		12,727
Associated British Foods PLC		1,828		62,885
BRF SA(a)		5,800		50,752
Calavo Growers, Inc.(b)		5,491		497,430
Chocoladefabriken Lindt & Spruengli AG		2		15,530
Chocoladefabriken Lindt & Spruengli AG, Registered Shares		1		88,345
Conagra Brands, Inc.		282		9,656
Danone SA		1,333		110,700
Freshpet, Inc.(a)(b)		10,897		643,904
General Mills, Inc.		1,252		67,057
Hershey Co.		6,405		941,407

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Food Products (continued)
Hormel Foods Corp.		4,729	$	213,325
Hostess Brands, Inc.(a)		22,013		320,069
J&J Snack Foods Corp.		2,593		477,812
JBS SA		145,236		931,486
John B Sanfilippo & Son, Inc.		3,696		337,371
Kerry Group PLC, Class A		365		45,487
Kraft Heinz Co.		650		20,884
Lamb Weston Holdings, Inc.		39		3,355
Lancaster Colony Corp.		135		21,613
McCormick & Co., Inc.(b)		121		20,537
MEIJI Holdings Co. Ltd.		200		13,516
Mondelez International, Inc., Class A		2,878		158,520
Mowi ASA		353		9,178
Nestle SA, Registered Shares		6,481		701,667
Orkla ASA		6,680		67,741
Simply Good Foods Co.(a)		7,516		214,507
Tingyi Cayman Islands Holding Corp.		192,000		327,694
Tyson Foods, Inc., Class A(b)		464		42,242
Uni-President China Holdings Ltd.		103,000		108,209
Uni-President Enterprises Corp.		431,000		1,068,806
Vitasoy International Holdings Ltd.(b)		10,000		36,276
Want Want China Holdings Ltd.		77,000		71,923
WH Group Ltd.(c)		10,500		10,857
Wilmar International Ltd.		51,300		157,168
Yakult Honsha Co. Ltd.		400		22,045
				7,902,681
Gas Utilities — 0.7%
Atmos Energy Corp.		546		61,075
Beijing Enterprises Holdings Ltd.		66,000		302,845
China Gas Holdings Ltd.		14,000		52,419
ENN Energy Holdings Ltd.		35,500		387,844
GAIL India Ltd.		334,386		566,822
Gujarat Gas Ltd.		15,259		50,783
Gujarat State Petronet Ltd.		24,106		74,130
Hong Kong & China Gas Co. Ltd.		62,000		121,140
Kunlun Energy Co. Ltd.		620,000		547,732
Mahanagar Gas Ltd.		4,989		74,474
Naturgy Energy Group SA		2,430		61,190
New Jersey Resources Corp.(b)		11,530		513,892
Petronas Gas Bhd		24,200		98,326
Snam SpA		3,508		18,444
Southwest Gas Holdings, Inc.		7,643		580,639
Tokyo Gas Co. Ltd.		400		9,720
				3,521,475
Health Care Equipment & Supplies — 1.7%
Abbott Laboratories(b)		7,162		622,091
ABIOMED, Inc.(a)(b)		29		4,947
Alcon, Inc.(a)		772		43,727
Align Technology, Inc.(a)		142		39,624
AtriCure, Inc.(a)(b)		2,977		96,782
Baxter International, Inc.		2,451		204,953
Becton Dickinson & Co.		705		191,739
Boston Scientific Corp.(a)		3,654		165,234
Carl Zeiss Meditec AG, Bearer Shares		111		14,111
Cochlear Ltd.		37		5,831
Coloplast A/S, Class B		458		56,820
Cooper Cos., Inc.		55		17,671
Danaher Corp.		1,877		288,082
DENTSPLY SIRONA, Inc.(b)		248		14,034
DexCom, Inc.(a)		1,115		243,895
Edwards Lifesciences Corp.(a)		2,989		697,304
Fisher & Paykel Healthcare Corp. Ltd.		1,694		25,352
GenMark Diagnostics, Inc.(a)		2,515		12,097

Security	Shares		Value
Health Care Equipment & Supplies (continued)
Globus Medical, Inc., Class A(a)		4,334	$	255,186
Hologic, Inc.(a)		6,796		354,819
Hoya Corp.		900		85,916
IDEXX Laboratories, Inc.(a)		1,324		345,736
Inogen, Inc.(a)(b)		6,101		416,881
Insulet Corp.(a)		67		11,470
Intuitive Surgical, Inc.(a)		272		160,793
iRhythm Technologies, Inc.(a)		3,075		209,377
Koninklijke Philips NV		1,894		92,586
LivaNova PLC(a)(b)		405		30,549
Masimo Corp.(a)(b)		180		28,451
Medtronic PLC		6,668		756,485
Merit Medical Systems, Inc.(a)(b)		1,934		60,380
Neogen Corp.(a)		305		19,904
Novocure Ltd.(a)		3,604		303,709
Olympus Corp.		2,800		43,156
Osstem Implant Co. Ltd.(a)		2,750		100,605
ResMed, Inc.		266		41,222
RTI Surgical Holdings, Inc.(a)(b)		12,556		34,403
SI-BONE, Inc.(a)		3,601		77,422
Siemens Healthineers AG(c)		1,067		51,149
Silk Road Medical, Inc.(a)		2,923		118,031
SmileDirectClub, Inc.(a)(b)		12,222		106,820
Smith & Nephew PLC		1,496		36,055
Sonova Holding AG, Registered Shares		100		22,861
Stryker Corp.(b)		7,286		1,529,623
Sysmex Corp.		300		20,426
Tactile Systems Technology, Inc.(a)(b)		228		15,392
Tandem Diabetes Care, Inc.(a)(b)		1,387		82,679
Teleflex, Inc.		75		28,233
Terumo Corp.		1,500		53,211
TransMedics Group, Inc.(a)(b)		1,439		27,355
Varian Medical Systems, Inc.(a)		83		11,787
Zimmer Biomet Holdings, Inc.		481		71,996
				8,348,962
Health Care Providers & Services — 1.9%
AmerisourceBergen Corp.		2,859		243,072
AMN Healthcare Services, Inc.(a)(b)		12,706		791,711
Anthem, Inc.		3,092		933,877
Apollo Hospitals Enterprise Ltd.		1,925		38,932
Cardinal Health, Inc.		348		17,602
Centene Corp.(a)		227		14,271
Chemed Corp.		1,028		451,559
Cigna Corp.(a)		1,617		330,660
CVS Health Corp.		13,392		994,892
DaVita, Inc.(a)		149		11,179
Fresenius Medical Care AG & Co. KGaA		461		33,942
Fresenius SE & Co. KGaA		881		49,577
HCA Healthcare, Inc.		800		118,248
HealthEquity, Inc.(a)(b)		10,960		811,807
Humana, Inc.		739		270,858
IHH Healthcare Bhd		93,100		124,649
Integer Holdings Corp.(a)		2,427		195,204
Laboratory Corp. of America Holdings(a)		182		30,789
LHC Group, Inc.(a)(b)		264		36,369
Magellan Health, Inc.(a)		1,143		89,440
McKesson Corp.		1,021		141,225
Patterson Cos., Inc.(b)		51,294		1,050,501
Penumbra, Inc.(a)(b)		421		69,158
PetIQ, Inc.(a)		1,594		39,930
Quest Diagnostics, Inc.		108		11,533
Ryman Healthcare Ltd.		1,537		16,893
Select Medical Holdings Corp.(a)		10,800		252,072
Sinopharm Group Co. Ltd., Class H		148,800		542,954

SCHEDULE OF INVESTMENTS 9

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Health Care Providers & Services (continued)
Tivity Health, Inc.(a)(b)		990	$	20,142
U.S. Physical Therapy, Inc.(b)		3,012		344,422
UnitedHealth Group, Inc.		5,006		1,471,664
Universal Health Services, Inc., Class B		153		21,949
WellCare Health Plans, Inc.(a)		200		66,042
				9,637,123
Health Care Technology — 0.6%
Allscripts Healthcare Solutions, Inc.(a)(b)		44,244		434,255
Castlight Health, Inc., Class B(a)		73,355		97,562
Cerner Corp.		394		28,916
Evolent Health, Inc., Class A(a)(b)		25,586		231,553
Inovalon Holdings, Inc., Class A(a)(b)		15,469		291,127
Inspire Medical Systems, Inc.(a)(b)		1,225		90,907
M3, Inc.		800		24,124
NextGen Healthcare, Inc.(a)		3,998		64,248
Omnicell, Inc.(a)		8,252		674,353
Phreesia, Inc.(a)		15,681		417,742
Teladoc Health, Inc.(a)(b)		2,206		184,686
Veeva Systems, Inc., Class A(a)		2,130		299,606
Vocera Communications, Inc.(a)(b)		1,589		32,988
				2,872,067
Hotels, Restaurants & Leisure — 1.5%
BJ’s Restaurants, Inc.(b)		11,329		430,049
Boyd Gaming Corp.		23,338		698,740
Brinker International, Inc.(b)		3,482		146,244
Carnival Corp.		3,066		155,845
Century Casinos, Inc.(a)		28,255		223,780
Cheesecake Factory, Inc.(b)		959		37,267
Chipotle Mexican Grill, Inc.(a)		15		12,557
Choice Hotels International, Inc.(b)		5,105		528,010
Churchill Downs, Inc.		4,187		574,456
Darden Restaurants, Inc.		4,419		481,715
Dunkin’ Brands Group, Inc.		1,217		91,932
Everi Holdings, Inc.(a)		1,826		24,523
Extended Stay America, Inc.		8,568		127,320
Genting Bhd		229,700		339,899
Genting Malaysia Bhd		190,200		153,095
Gourmet Master Co. Ltd.		8,000		33,018
International Game Technology PLC(b)		3,104		46,467
J Alexander’s Holdings, Inc.(a)		4,680		44,741
Jubilant Foodworks Ltd.		6,507		150,732
McDonald’s Corp.		3,842		759,218
OPAP SA		4,323		56,245
Penn National Gaming, Inc.(a)		4,126		105,461
Ruth’s Hospitality Group, Inc.		4,458		97,028
Starbucks Corp.		223		19,606
Target Hospitality Corp.(a)(b)		15,756		78,780
Texas Roadhouse, Inc.(b)		30,258		1,704,130
Wingstop, Inc.		1,974		170,218
Wyndham Destinations, Inc.		543		28,068
Yum China Holdings, Inc.		6,520		313,025
				7,632,169
Household Durables — 0.8%
Bassett Furniture Industries, Inc.		4,635		77,312
Century Communities, Inc.(a)		2,549		69,715
D.R. Horton, Inc.		6,793		358,331
Green Brick Partners, Inc.(a)(b)		6,016		69,064
Helen of Troy Ltd.(a)(b)		752		135,202
Hooker Furniture Corp.		5,569		143,068
iRobot Corp.(a)(b)		1,048		53,060
KB Home		2,654		90,953
La-Z-Boy, Inc.		1,963		61,795
Lennar Corp., Class A(b)		1,412		78,775

Security	Shares		Value
Household Durables (continued)
LG Electronics, Inc.		14,681	$	911,942
LGI Homes, Inc.(a)(b)		872		61,607
M/I Homes, Inc.(a)		4,035		158,777
MDC Holdings, Inc.		24,122		920,496
Meritage Homes Corp.(a)		5,457		333,477
NVR, Inc.(a)		13		49,509
PulteGroup, Inc.		892		34,610
SEB SA		65		9,667
Sony Corp.		1,600		108,636
TopBuild Corp.(a)		2,766		285,119
TRI Pointe Group, Inc.(a)		872		13,586
				4,024,701
Household Products — 0.8%
Central Garden & Pet Co.(a)		660		20,506
Church & Dwight Co., Inc.		7,651		538,171
Clorox Co.		445		68,325
Colgate-Palmolive Co.		2,628		180,912
Henkel AG & Co. KGaA		319		29,984
Kimberly-Clark Corp.		1,380		189,819
Kimberly-Clark de Mexico SAB de CV, Class A(a)		98,500		195,359
LG Household & Health Care Ltd.		429		466,002
Lion Corp.		300		5,832
Procter & Gamble Co.		18,566		2,318,893
Reckitt Benckiser Group PLC		1,585		128,747
Unicharm Corp.		400		13,507
				4,156,057
Independent Power and Renewable Electricity Producers — 0.1%
Huaneng Power International, Inc., Class H		32,000		16,181
Meridian Energy Ltd.		5,962		20,083
TerraForm Power, Inc., Class A		11,724		180,433
Uniper SE		509		16,823
				233,520
Industrial Conglomerates — 0.4%
3M Co.		536		94,561
Carlisle Cos., Inc.		870		140,801
CITIC Ltd.		57,000		76,079
DCC PLC		632		54,819
Honeywell International, Inc.		3,147		557,019
KOC Holding AS		84,786		289,755
NWS Holdings Ltd.		18,000		25,228
Roper Technologies, Inc.		1,195		423,305
Siemens AG, Registered Shares		2,012		262,750
Smiths Group PLC		1,288		28,768
Toshiba Corp.		600		20,365
				1,973,450
Insurance — 2.6%
Admiral Group PLC		323		9,870
Aflac, Inc.		3,961		209,537
Ageas		137		8,101
AIA Group Ltd.		22,600		237,706
Alleghany Corp.(a)		16		12,793
Allianz SE, Registered Shares		1,157		283,497
Allstate Corp.		6,936		779,953
American Financial Group, Inc.		61		6,689
American International Group, Inc.		4,337		222,618
Aon PLC		1,069		222,662
Arch Capital Group Ltd.(a)		725		31,095
Arthur J Gallagher & Co.		2,960		281,881
Assicurazioni Generali SpA		4,950		102,192
Assurant, Inc.		76		9,962
Athene Holding Ltd., Class A(a)		496		23,327
Aviva PLC		6,700		37,189

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Insurance (continued)
AXA SA		4,365	$	123,338
Bajaj Finserv Ltd.		1,238		162,995
Baloise Holding AG, Registered Shares		83		15,022
Brown & Brown, Inc.		5,399		213,152
BRP Group, Inc.(a)		2,788		44,747
Cathay Financial Holding Co. Ltd.		74,476		105,746
China Life Insurance Co. Ltd.(a)		29,948		25,568
China Life Insurance Co. Ltd., Class A		12,652		63,524
China Life Insurance Co. Ltd., Class H		730,000		2,030,609
China Pacific Insurance Group Co. Ltd., Class A		24,800		135,043
China Pacific Insurance Group Co. Ltd., Class H		12,800		50,432
Cincinnati Financial Corp.		3,728		391,999
CNO Financial Group, Inc.(b)		37,565		681,053
CNP Assurances		294		5,858
Dai-ichi Life Holdings, Inc.		1,800		29,664
Direct Line Insurance Group PLC		2,352		9,731
Discovery Ltd.		8,800		75,792
Employers Holdings, Inc.		10,869		453,781
Everest Re Group Ltd.		51		14,119
FedNat Holding Co.		6,938		115,379
Fidelity National Financial, Inc.		564		25,577
First American Financial Corp.		5,541		323,151
Gjensidige Forsikring ASA		155		3,254
Globe Life, Inc.		2,929		308,277
Hannover Rueck SE		282		54,374
Hanwha Life Insurance Co. Ltd.		43,151		86,009
Hartford Financial Services Group, Inc.		1,209		73,471
HCI Group, Inc.(b)		909		41,496
Heritage Insurance Holdings, Inc.		2,252		29,839
Insurance Australia Group Ltd.		2,815		15,125
Investors Title Co.		19		3,025
IRB Brasil Resseguros S/A		16,700		161,699
Japan Post Holdings Co. Ltd.		8,100		76,176
Kinsale Capital Group, Inc.(b)		641		65,164
Legal & General Group PLC		10,196		40,958
Lincoln National Corp.		1,779		104,979
Mapfre SA		1,844		4,889
Markel Corp.(a)		42		48,013
Marsh & McLennan Cos., Inc.		3,007		335,010
MetLife, Inc.		8,769		446,956
MS&AD Insurance Group Holdings, Inc.		1,500		49,513
Muenchener Rueckversicherungs-Gesellschaft AG, Registered Shares		418		123,349
National General Holdings Corp.		2,480		54,808
New China Life Insurance Co. Ltd., Class A		9,600		67,925
NN Group NV		516		19,620
Ping An Insurance Group Co. of China Ltd., Class H		89,000		1,053,178
Poste Italiane SpA(c)		1,575		17,897
Principal Financial Group, Inc.		816		44,880
Progressive Corp.		3,914		283,334
Protective Insurance Corp., Class B		3,231		51,987
Prudential Financial, Inc.(b)		5,120		479,949
Prudential PLC		4,408		84,460
QBE Insurance Group Ltd.		791		7,148
Reinsurance Group of America, Inc.		82		13,371
RenaissanceRe Holdings Ltd.		26		5,096
RSA Insurance Group PLC		1,764		13,221
Sampo OYJ, Class A		1,239		54,099
SCOR SE		271		11,408
Sompo Holdings, Inc.		500		19,635
Sony Financial Holdings, Inc.		200		4,801
Swiss Life Holding AG, Registered Shares		59		29,599
Swiss Re AG		798		89,649
T&D Holdings, Inc.		900		11,381

Security	Shares		Value
Insurance (continued)
Tokio Marine Holdings, Inc.		2,000	$	111,978
Travelers Cos., Inc.		1,431		195,975
United Insurance Holdings Corp.		1,995		25,157
Universal Insurance Holdings, Inc.		1,903		53,265
Unum Group		7,443		217,038
W.R. Berkley Corp.		960		66,336
Watford Holdings Ltd.(a)		548		13,788
Willis Towers Watson PLC		750		151,455
Zurich Insurance Group AG		407		166,951
				13,066,317
Interactive Media & Services — 3.4%
Alphabet, Inc., Class A(a)		2,094		2,804,683
Alphabet, Inc., Class C(a)		2,141		2,862,560
Auto Trader Group PLC(c)		367		2,898
Baidu, Inc. — ADR(a)		5,181		654,878
Care.com, Inc.(a)		1,192		17,916
Cargurus, Inc.(a)(b)		10,451		367,666
Cars.com, Inc.(a)		9,462		115,626
EverQuote, Inc., Class A(a)		3,920		134,652
Facebook, Inc., Class A(a)		17,359		3,562,935
IAC/InterActiveCorp.(a)		170		42,349
JOYY, Inc., ADR(a)		782		41,282
Just Dial Ltd.(a)		22,976		183,913
Momo, Inc., ADR		2,461		82,443
Pinterest, Inc., Class A, Class A(a)		4,705		87,701
Snap, Inc., Class A(a)		2,176		35,534
Tencent Holdings Ltd.		110,000		5,299,374
TripAdvisor, Inc.		3,996		121,398
TrueCar, Inc.(a)		23,092		109,687
Twitter, Inc.(a)		6,273		201,050
Yandex NV, Class A(a)		2,534		110,204
Yelp, Inc.(a)		15,317		533,491
Z Holdings Corp.		4,500		18,999
Zillow Group, Inc., Class C(a)(b)		293		13,460
				17,404,699
Internet & Direct Marketing Retail — 3.3%
1-800-Flowers.com, Inc., Class A(a)		12,050		174,725
Alibaba Group Holding Ltd.(a)		19,500		518,512
Alibaba Group Holding Ltd. — ADR(a)		31,651		6,713,177
Amazon.com, Inc.(a)		3,244		5,994,393
Booking Holdings, Inc.(a)(b)		184		377,886
eBay, Inc.		929		33,546
Expedia Group, Inc.		410		44,337
GrubHub, Inc.(a)(b)		405		19,699
JD.com, Inc. — ADR(a)		50,584		1,782,074
Meituan Dianping, Class B(a)		3,100		40,505
MercadoLibre, Inc.(a)		109		62,341
Naspers Ltd., Class N		4,275		699,591
Prosus NV(a)		956		71,549
Qurate Retail, Inc., Series A(a)		2,289		19,296
Stitch Fix, Inc., Class A(a)(b)		801		20,554
Vipshop Holdings Ltd. — ADR(a)		20,988		297,400
Wayfair, Inc., Class A(a)(b)		342		30,907
				16,900,492
IT Services — 3.3%
Accenture PLC, Class A		2,575		542,218
Adyen NV(a)(c)		34		27,968
Alliance Data Systems Corp.		75		8,415
Amadeus IT Group SA		1,212		99,259
Automatic Data Processing, Inc.		7,109		1,212,084
Black Knight, Inc.(a)(b)		474		30,564
Broadridge Financial Solutions, Inc.(b)		3,233		399,405
Cognizant Technology Solutions Corp., Class A		1,805		111,946

SCHEDULE OF INVESTMENTS 11

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
IT Services (continued)
CSG Systems International, Inc.		13,997	$	724,765
Fidelity National Information Services, Inc.		2,646		368,032
Fiserv, Inc.(a)(b)		2,150		248,604
FleetCor Technologies, Inc.(a)		60		17,263
Fujitsu Ltd.		300		28,217
Genpact Ltd.		13,173		555,505
Global Payments, Inc.		952		173,797
GoDaddy, Inc., Class A(a)		3,091		209,941
Hackett Group, Inc.		17,257		278,528
Infosys Ltd.		103,706		1,067,967
Infosys Ltd. — ADR(b)		88,052		908,697
International Business Machines Corp.		4,190		561,628
International Money Express, Inc.(a)(b)		6,289		75,720
Jack Henry & Associates, Inc.(b)		2,353		342,761
LiveRamp Holdings, Inc.(a)(b)		6,210		298,515
ManTech International Corp., Class A		10,495		838,341
Mastercard, Inc., Class A		9,964		2,975,151
Mphasis Ltd.		12,282		158,691
NEC Corp.		300		12,415
Okta, Inc.(a)(b)		311		35,880
Paychex, Inc.(b)		12,769		1,086,131
PayPal Holdings, Inc.(a)		5,232		565,945
Perficient, Inc.(a)(b)		4,215		194,185
Perspecta, Inc.		620		16,393
Samsung SDS Co. Ltd.		1,182		198,369
Square, Inc., Class A(a)		1,091		68,253
Tech Mahindra Ltd.		6,702		71,576
Twilio, Inc., Class A(a)		300		29,484
VeriSign, Inc.(a)		189		36,416
Verra Mobility Corp.(a)(b)		1,605		22,454
Visa, Inc., Class A		9,928		1,865,471
Wipro Ltd.		19,262		66,326
Wipro Ltd. — ADR		52,692		197,595
Wirecard AG		145		17,484
Worldline SA(a)(c)		250		17,723
				16,766,082
Leisure Products — 0.1%
Malibu Boats, Inc., Class A(a)		7,453		305,200
Life Sciences Tools & Services — 0.4%
10X Genomics, Inc., Class A(a)		1,664		126,880
Adaptive Biotechnologies Corp.(a)		1,018		30,459
Agilent Technologies, Inc.		480		40,949
Illumina, Inc.(a)(b)		421		139,663
IQVIA Holdings, Inc.(a)		387		59,795
Lonza Group AG, Registered Shares(a)		103		37,575
Medpace Holdings, Inc.(a)		4,005		336,660
Mettler-Toledo International, Inc.(a)(b)		34		26,971
NanoString Technologies, Inc.(a)		3,857		107,302
NeoGenomics, Inc.(a)(b)		2,534		74,119
Personalis, Inc.(a)		3,251		35,436
QIAGEN NV(a)		383		13,050
Repligen Corp.(a)		978		90,465
Syneos Health, Inc.(a)		5,587		332,287
Thermo Fisher Scientific, Inc.		2,092		679,628
Waters Corp.(a)		84		19,627
				2,150,866
Machinery — 2.1%
AGCO Corp.		2,182		168,560
Albany International Corp., Class A		2,456		186,460
Alfa Laval AB		223		5,616
ANDRITZ AG		1,348		57,951
Atlas Copco AB, A Shares		3,897		155,551
Atlas Copco AB, Class B		881		30,589

Security	Shares		Value
Machinery (continued)
Blue Bird Corp.(a)		7,049	$	161,563
Cummins, Inc.		1,246		222,984
Daifuku Co. Ltd.		700		42,304
Deere & Co.		2,018		349,639
Doosan Infracore Co. Ltd.(a)		51,964		248,737
Epiroc AB, Class A		4,839		59,177
Epiroc AB, Class B		1,012		12,027
ESCO Technologies, Inc.		10,869		1,005,383
Evoqua Water Technologies Corp.(a)		22,994		435,736
FANUC Corp.		700		129,265
GEA Group AG		257		8,498
Greenbrier Cos., Inc.		1,168		37,878
Hillenbrand, Inc.		10,069		335,398
IDEX Corp.		2,044		351,568
Illinois Tool Works, Inc.		759		136,339
Ingersoll-Rand PLC		711		94,506
Iochpe-Maxion SA		47,806		277,849
John Bean Technologies Corp.(b)		599		67,483
JTEKT Corp.		600		7,088
KION Group AG		190		13,066
Knorr-Bremse AG		958		97,519
Komatsu Ltd.		600		14,401
Kone OYJ, Class B		3,168		207,149
Kubota Corp.		3,400		53,391
Kurita Water Industries Ltd.		1,400		41,545
Lonking Holdings Ltd.		371,000		111,471
Miller Industries, Inc.		8,335		309,479
MINEBEA MITSUMI, Inc.		2,200		45,444
MISUMI Group, Inc.		1,600		39,600
Mitsubishi Heavy Industries Ltd.		1,600		62,043
Nabtesco Corp.		200		5,893
NSK Ltd.		5,400		51,047
Oshkosh Corp.		6,778		641,538
PACCAR, Inc.(b)		15,877		1,255,871
Parker-Hannifin Corp.		14		2,882
Rexnord Corp.(a)		11,638		379,632
Schindler Holding AG, Participation Certificates		390		99,177
Schindler Holding AG, Registered Shares		280		68,570
Sinotruk Hong Kong Ltd.		13,500		28,813
SMC Corp.		200		91,463
Snap-on, Inc.(b)		1,344		227,674
Spirax-Sarco Engineering PLC		120		14,126
Techtronic Industries Co. Ltd.		3,000		24,485
Wabash National Corp.		8,355		122,735
WABCO Holdings, Inc.(a)		360		48,780
Wartsila OYJ Abp	��	674		7,450
Weichai Power Co. Ltd., Class H		377,000		795,743
Westinghouse Air Brake Technologies Corp.		1,984		154,355
Woodward, Inc.		3,927		465,114
Xylem, Inc.(b)		157		12,370
Yaskawa Electric Corp.		200		7,534
Zoomlion Heavy Industry Science and Technology Co. Ltd., Class A		283,098		272,248
Zoomlion Heavy Industry Science and Technology Co. Ltd., Class H		436,000		365,474
				10,726,231
Marine — 0.1%
AP Moeller — Maersk A/S, Class A		23		31,176
Kuehne + Nagel International AG, Registered Shares		335		56,503
MISC Bhd		124,500		254,374
				342,053
Media — 0.7%
AMC Networks, Inc., Class A(a)		4,087		161,436

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Media (continued)
Cardlytics, Inc.(a)		460	$	28,916
Cheil Worldwide, Inc.		2,585		53,759
Comcast Corp., Class A		15,121		679,991
Discovery, Inc., Class A(a)(b)		7,939		259,923
Discovery, Inc., Class C(a)		892		27,197
Emerald Expositions Events, Inc.		2,571		27,124
Entravision Communications Corp., Class A		23,429		61,384
EW Scripps Co., Class A		4,565		71,716
Gray Television, Inc.(a)		6,598		141,461
iHeartMedia, Inc., Class A(a)(b)		27,754		469,043
Interpublic Group of Cos., Inc.		22,012		508,477
Liberty Media Corp. — Liberty SiriusXM, Class A(a)		337		16,291
Marchex, Inc., Class B(a)		5,595		21,149
McClatchy Co., Class A(a)		3,156		1,515
MSG Networks, Inc., Class A(a)		4,505		78,387
MultiChoice Group Ltd.(a)		29,749		247,846
Sirius XM Holdings, Inc.		76,812		549,206
Townsquare Media, Inc., Class A(b)		4,560		45,463
ViacomCBS, Inc., Class B Class B(b)		1,833		76,931
Zee Entertainment Enterprises Ltd.		15,988		65,450
				3,592,665
Metals & Mining — 1.9%
Alcoa Corp.(a)(b)		8,775		188,750
Anglo American Platinum Ltd.		13,678		1,276,714
AngloGold Ashanti Ltd.		8,536		193,902
ArcelorMittal SA		2,648		46,657
Carpenter Technology Corp.		1,031		51,323
Fortescue Metals Group Ltd.		12,712		95,828
Glencore PLC(a)		26,441		82,330
Gold Fields Ltd.		15,095		103,033
Gold Fields Ltd. — ADR		45,262		298,729
Hindalco Industries Ltd.		128,016		388,097
Hochschild Mining PLC		52,450		127,154
Hyundai Steel Co.		987		26,760
Impala Platinum Holdings Ltd.(a)		8,069		82,444
Industrias Penoles SAB de CV		3		31
Jiangxi Copper Co. Ltd., Class H		40,000		55,015
Kaiser Aluminum Corp.		168		18,630
Korea Zinc Co. Ltd.		141		51,814
Magnitogorsk Iron & Steel Works PJSC		434,684		293,976
Magnitogorsk Iron & Steel Works PJSC, — GDR		4,861		42,163
Maruichi Steel Tube Ltd.		300		8,431
Materion Corp.(b)		9,342		555,382
MMC Norilsk Nickel PJSC		1,429		439,629
MMC Norilsk Nickel PJSC, ADR		20,494		626,732
Nippon Steel Corp.		4,000		60,292
Nucor Corp.		11,728		660,052
Olympic Steel, Inc.		2,566		45,983
POSCO		6,712		1,364,305
POSCO — ADR		5,906		298,962
Reliance Steel & Aluminum Co.		1,460		174,850
Rio Tinto Ltd.		2,778		196,543
Rio Tinto PLC		6,898		408,327
Ryerson Holding Corp.(a)		12,781		151,199
Schnitzer Steel Industries, Inc., Class A		713		15,458
Severstal PAO — GDR		7,444		112,654
Severstal PJSC		41,415		626,346
Steel Dynamics, Inc.		13,982		475,947
Warrior Met Coal, Inc.(b)		712		15,045
Zijin Mining Group Co. Ltd., Class H		214,000		106,287
				9,765,774
Mortgage Real Estate Investment Trusts (REITs) — 0.2%
AGNC Investment Corp.		1,341		23,709

Security	Shares		Value
Mortgage Real Estate Investment Trusts (REITs) (continued)
Annaly Capital Management, Inc.		2,760	$	25,999
Ellington Financial, Inc.		628		11,511
Great Ajax Corp.		5,098		75,502
Invesco Mortgage Capital, Inc.(b)		47,362		788,577
KKR Real Estate Finance Trust, Inc.(b)		2,439		49,804
				975,102
Multi-Utilities — 0.4%
Ameren Corp.		8,369		642,739
Avista Corp.		6,836		328,743
Consolidated Edison, Inc.		2,858		258,563
DTE Energy Co.		5,484		712,207
E.ON SE		3,765		40,236
Engie SA		3,124		50,604
National Grid PLC		1,140		14,247
Public Service Enterprise Group, Inc.		1,058		62,475
				2,109,814
Multiline Retail — 0.2%
Dollar General Corp.		3,623		565,115
Kohl’s Corp.		249		12,687
Target Corp.		1,789		229,368
				807,170
Oil, Gas & Consumable Fuels — 4.0%
Aker BP ASA		185		6,072
Apache Corp.(b)		2,061		52,741
Arch Coal, Inc., Class A(b)		1,666		119,519
Ardmore Shipping Corp.(a)		7,033		63,649
BP PLC		44,642		280,834
Brigham Minerals, Inc., Class A		610		13,078
Cabot Oil & Gas Corp.		2,564		44,639
Callon Petroleum Co.(a)		17,433		84,201
Cheniere Energy, Inc.(a)		58		3,542
Chevron Corp.		6,970		839,955
China Coal Energy Co. Ltd., Class H		102,000		40,479
China Petroleum & Chemical Corp., Class H		60,000		36,128
China Shenhua Energy Co. Ltd., Class H		182,500		381,590
CNOOC Ltd.		631,000		1,049,245
CNOOC Ltd. — ADR		1,231		205,171
Concho Resources, Inc.(b)		1,143		100,093
ConocoPhillips		10,064		654,462
Continental Resources, Inc.(b)		6,560		225,008
Cosan Ltd., Class A(a)		2,782		63,541
CVR Energy, Inc.		1,214		49,082
Delek US Holdings, Inc.(b)		2,547		85,401
Devon Energy Corp.		4,583		119,021
Diamondback Energy, Inc.		920		85,431
Eni SpA		9,729		151,103
EOG Resources, Inc.		10,545		883,249
Equinor ASA		3,943		78,632
Evolution Petroleum Corp.(b)		40,922		223,843
Exxon Mobil Corp.		41,468		2,893,637
Galp Energia SGPS SA		1,390		23,335
Geopark Ltd.		10,087		222,923
Hess Corp.		1,485		99,213
HollyFrontier Corp.		136		6,897
Inpex Corp.		3,800		39,367
JXTG Holdings, Inc.		5,500		24,962
Kinder Morgan, Inc.		14,724		311,707
Koninklijke Vopak NV		120		6,521
Laredo Petroleum, Inc.(a)		49,833		143,021
LUKOIL PJSC		9,459		938,815
Lukoil PJSC — ADR		16,419		1,635,440
Lundin Petroleum AB		101		3,429
Marathon Oil Corp.		7,725		104,906

SCHEDULE OF INVESTMENTS 13

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Oil, Gas & Consumable Fuels (continued)
Marathon Petroleum Corp.		10,535	$	634,734
Matador Resources Co.(a)(b)		18,805		337,926
MOL Hungarian Oil & Gas PLC		8,898		88,696
Neste OYJ		1,052		36,604
Noble Energy, Inc.(b)		25,553		634,737
Nordic American Tankers Ltd.		18,788		92,437
Novatek PJSC — GDR		1,627		330,281
Occidental Petroleum Corp.		3,677		151,529
Oil Search Ltd.		2,696		13,747
OMV AG		761		42,635
ONEOK, Inc.		1,047		79,226
Penn Virginia Corp.(a)(b)		657		19,940
PetroChina Co. Ltd., Class H		1,268,000		638,305
Petronas Dagangan Bhd		7,600		42,919
Petronet LNG Ltd.		110,942		416,612
Phillips 66		2,407		268,164
Pioneer Natural Resources Co.(b)		877		132,752
Polski Koncern Naftowy ORLEN SA		16,730		378,425
Reliance Industries Ltd.		9,978		211,654
Repsol SA		3,312		52,032
S-Oil Corp.		2,974		244,260
Santos Ltd.		6,394		36,784
Scorpio Tankers, Inc.		8,746		344,068
Shaanxi Coal Industry Co. Ltd.		125,000		161,612
Star Petroleum Refining PCL		128,600		45,882
Tatneft PAO — ADR		3,068		226,602
Tatneft PJSC		28,364		347,472
Teekay Corp.(b)		3,448		18,343
TOTAL SA		5,388		298,983
Tupras Turkiye Petrol Rafinerileri AS		5,638		120,130
Ultrapar Participacoes SA		74,555		472,235
Valero Energy Corp.		4,333		405,785
Williams Cos., Inc.		13,725		325,557
Woodside Petroleum Ltd.		3,369		81,458
				20,126,408
Paper & Forest Products — 0.2%
Boise Cascade Co.		23,133		845,048
Clearwater Paper Corp.(a)		2,742		58,569
Domtar Corp.		8,241		315,136
				1,218,753
Personal Products — 0.4%
Amorepacific Corp.		2,068		356,145
Beiersdorf AG		466		55,747
Coty, Inc., Class A		1,936		21,780
elf Beauty, Inc.(a)		1,891		30,502
Estee Lauder Cos., Inc., Class A(b)		4,697		970,118
Kao Corp.		800		65,980
L’Oreal SA		500		147,854
Natural Health Trends Corp.		3,327		17,899
Shiseido Co. Ltd.		500		35,505
Unilever NV		2,965		170,163
Unilever PLC		2,768		158,448
USANA Health Sciences, Inc.(a)		809		63,547
				2,093,688
Pharmaceuticals — 3.8%
Acer Therapeutics, Inc.(a)(b)		8,356		33,508
Ajanta Pharma Ltd.		2,386		32,579
Allergan PLC		2,575		492,263
Amneal Pharmaceuticals, Inc.(a)		36,680		176,798
Amphastar Pharmaceuticals, Inc.(a)(b)		7,033		135,667
Astellas Pharma, Inc.		4,500		76,815
AstraZeneca PLC		2,547		254,934
Asymchem Laboratories Tianjin Co. Ltd., Class A		1,800		33,509

Security	Shares		Value
Pharmaceuticals (continued)
Aurobindo Pharma Ltd.		5,568	$	35,638
Bristol-Myers Squibb Co.		26,957		1,730,370
Cara Therapeutics, Inc.(a)(b)		2,377		38,293
Changchun High & New Technology Industry Group, Inc., Class A		2,800		179,967
China Medical System Holdings Ltd.		56,000		80,606
China Resources Pharmaceutical Group Ltd.(c)		44,000		40,790
Chugai Pharmaceutical Co. Ltd.		900		82,886
Cipla Ltd.		96,451		646,278
Corcept Therapeutics, Inc.(a)		10,322		124,896
Daiichi Sankyo Co. Ltd.		1,200		79,253
Dr. Reddy’s Laboratories Ltd.		3,612		145,582
Eisai Co. Ltd.		500		37,413
Elanco Animal Health, Inc.(a)(b)		4,156		122,394
Eli Lilly & Co.		5,370		705,779
Endo International PLC(a)		9,589		44,972
GlaxoSmithKline PLC		10,401		244,393
Glenmark Pharmaceuticals Ltd.		70,165		341,545
Guangzhou Baiyunshan Pharmaceutical Holdings Co. Ltd., Class H		8,000		27,330
H Lundbeck A/S		155		5,926
Horizon Therapeutics PLC(a)		7,732		279,898
Innoviva, Inc.(a)		3,846		54,459
Intersect ENT, Inc.(a)		7,608		189,439
Intra-Cellular Therapies, Inc.(a)		3,891		133,500
Jazz Pharmaceuticals PLC(a)		674		100,615
Jiangsu Hengrui Medicine Co. Ltd., Class A		25,600		322,263
Johnson & Johnson		24,051		3,508,319
Kyowa Kirin Co. Ltd.		1,000		23,560
Merck & Co., Inc.		27,351		2,487,573
Merck KGaA		529		62,366
Mitsubishi Tanabe Pharma Corp.		700		12,842
Mylan NV(a)		13,753		276,435
NGM Biopharmaceuticals, Inc.(a)		9,986		184,641
Novo Nordisk A/S, Class B		4,185		242,516
Ono Pharmaceutical Co. Ltd.		1,000		22,830
Orion OYJ, Class B		179		8,290
Otsuka Holdings Co. Ltd.		1,000		44,574
Pacira BioSciences, Inc.(a)(b)		3,112		140,974
Perrigo Co. PLC		1,737		89,733
Pfizer, Inc.		44,217		1,732,422
Prestige Consumer Healthcare, Inc.(a)(b)		16,989		688,054
Reata Pharmaceuticals, Inc., Class A(a)(b)		1,790		365,930
Recordati SpA		180		7,588
Richter Gedeon Nyrt		10,933		237,701
Roche Holding AG		1,600		520,004
Sanofi		2,274		228,372
Santen Pharmaceutical Co. Ltd.		600		11,426
Shionogi & Co. Ltd.		800		49,489
Sino Biopharmaceutical Ltd.		41,000		57,360
Sumitomo Dainippon Pharma Co. Ltd.		300		5,813
Supernus Pharmaceuticals, Inc.(a)		5,981		141,869
Taisho Pharmaceutical Holdings Co. Ltd.		100		7,380
Takeda Pharmaceutical Co. Ltd.		2,900		114,701
Teva Pharmaceutical Industries Ltd. — ADR(a)		1,869		18,316
TherapeuticsMD, Inc.(a)(b)		4,394		10,633
Tricida, Inc.(a)		315		11,888
UCB SA		216		17,188
Zoetis, Inc.		8,259		1,093,079
				19,454,424
Professional Services — 0.7%
ASGN, Inc.(a)(b)		8,796		624,252
Centre Testing International Group Co. Ltd.		35,600		76,363
CoStar Group, Inc.(a)		18		10,770

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Professional Services (continued)
CRA International, Inc.		3,909	$	212,923
Experian PLC		1,704		57,765
Forrester Research, Inc.		761		31,734
IHS Markit Ltd.(a)		2,025		152,584
Insperity, Inc.(b)		10,348		890,342
Kforce, Inc.		14,386		571,124
Recruit Holdings Co. Ltd.		1,900		71,165
RELX PLC		1,929		48,694
Robert Half International, Inc.(b)		6,562		414,390
SEEK Ltd.		7,591		120,148
SGS SA, Registered Shares		37		101,331
Teleperformance		415		101,392
TriNet Group, Inc.(a)		4,893		276,993
				3,761,970
Real Estate Management & Development — 0.4%
Aroundtown SA		2,580		23,173
Azrieli Group Ltd.		264		19,339
Beijing Capital Development Co. Ltd.		58,200		66,684
CBRE Group, Inc., Class A(a)(b)		230		14,097
China Aoyuan Group Ltd.		39,000		63,638
CK Asset Holdings Ltd.		5,500		39,689
Daito Trust Construction Co. Ltd.		100		12,358
Daiwa House Industry Co. Ltd.		1,300		40,244
Dar Al Arkan Real Estate Development Co.(a)		13,465		39,514
Deutsche Wohnen SE, Bearer Shares		782		31,809
Emaar Properties PJSC		94,788		103,851
Greenland Holdings Corp. Ltd., Class A		245,000		244,662
Hang Lung Properties Ltd.		3,000		6,587
Hemisphere Properties India Ltd.(a)		27,195		58,662
Henderson Land Development Co. Ltd.		6,000		29,442
Hongkong Land Holdings Ltd.		4,200		24,159
Hulic Co. Ltd.		500		6,020
Jinke Properties Group Co. Ltd.		95,100		104,900
Kerry Properties Ltd.		1,000		3,176
Lendlease Group		527		6,516
Mitsubishi Estate Co. Ltd.		3,000		57,405
Mitsui Fudosan Co. Ltd.		2,000		48,880
Multiplan Empreendimentos Imobiliarios SA		7,900		65,004
New World Development Co. Ltd.		10,000		13,707
RE/MAX Holdings, Inc., Class A(b)		12,166		468,269
RMR Group, Inc., Class A		4,071		185,800
Sino Land Co. Ltd.		4,000		5,806
SM Prime Holdings, Inc.		52,100		43,243
Sumitomo Realty & Development Co. Ltd.		800		27,912
Sun Hung Kai Properties Ltd.		4,000		61,259
Swire Pacific Ltd., Class A		500		4,645
Swire Properties Ltd.		5,400		17,889
Swiss Prime Site AG, Registered Shares(a)		130		15,040
Vonovia SE		1,375		73,850
Wharf Real Estate Investment Co. Ltd.		2,000		12,203
Wheelock & Co. Ltd.		1,000		6,666
				2,046,098
Road & Rail — 0.5%
AMERCO(b)		101		37,958
Central Japan Railway Co.		400		80,428
Covenant Transportation Group, Inc., Class A(a)(b)		18,895		244,218
CSX Corp.		5,269		381,265
East Japan Railway Co.		1,000		90,262
Hankyu Hanshin Holdings, Inc.		400		17,110
JB Hunt Transport Services, Inc.		309		36,085
Landstar System, Inc.(b)		2,890		329,084
Lyft, Inc., Class A(a)		465		20,004
Marten Transport Ltd.		5,858		125,889

Security	Shares		Value
Road & Rail (continued)
Norfolk Southern Corp.		739	$	143,462
Old Dominion Freight Line, Inc.(b)		781		148,218
Saia, Inc.(a)(b)		853		79,431
Tokyu Corp.		900		16,643
Uber Technologies, Inc.(a)(b)		1,526		45,383
Union Pacific Corp.		2,477		447,817
Universal Logistics Holdings, Inc.		11,266		213,603
US Xpress Enterprises, Inc., Class A(a)		7,689		38,676
West Japan Railway Co.		200		17,299
				2,512,835
Semiconductors & Semiconductor Equipment — 3.6%
Advantest Corp.		400		22,559
Ambarella, Inc.(a)		14,764		894,108
Amkor Technology, Inc.(a)		64,740		841,620
Analog Devices, Inc.		171		20,322
Applied Materials, Inc.		8,845		539,899
ASM Pacific Technology Ltd.		1,500		20,821
ASML Holding NV		423		125,232
Broadcom, Inc.		620		195,932
Brooks Automation, Inc.		380		15,945
Cirrus Logic, Inc.(a)		22,367		1,843,264
Cypress Semiconductor Corp.		1,467		34,225
Elan Microelectronics Corp.		48,000		146,232
FormFactor, Inc.(a)		6,722		174,570
Inphi Corp.(a)		2,582		191,120
Intel Corp.		26,949		1,612,898
Lam Research Corp.		2,146		627,490
MediaTek, Inc.		100,000		1,481,708
Micron Technology, Inc.(a)		3,913		210,441
Novatek Microelectronics Corp.		7,000		51,289
NVIDIA Corp.		3,470		816,491
Parade Technologies Ltd.		2,000		41,112
Pixart Imaging, Inc.		12,000		59,262
Power Integrations, Inc.		535		52,917
QUALCOMM, Inc.(b)		4,480		395,270
Radiant Opto-Electronics Corp.		56,000		224,217
Realtek Semiconductor Corp.		128,000		1,005,853
Skyworks Solutions, Inc.		1,273		153,880
SunPower Corp.(a)		1,795		14,001
Taiwan Semiconductor Manufacturing Co. Ltd.		511,000		5,655,658
Texas Instruments, Inc.		3,589		460,433
Tokyo Electron Ltd.		100		21,833
United Microelectronics Corp.		512,000		280,550
				18,231,152
Software — 4.1%
Adobe, Inc.(a)		3,588		1,183,358
Alarm.com Holdings, Inc.(a)(b)		4,610		198,092
Autodesk, Inc.(a)		270		49,534
Benefitfocus, Inc.(a)		43,830		961,630
Bill.Com Holdings, Inc.(a)		712		27,092
Birlasoft Ltd.(a)		35,982		35,640
Bottomline Technologies DE, Inc.(a)(b)		11,963		641,217
Box, Inc., Class A(a)(b)		7,818		131,186
Cadence Design Systems, Inc.(a)(b)		919		63,742
Cloudera, Inc.(a)(b)		13,728		159,657
Cloudflare, Inc., Class A(a)		3,841		65,527
CommVault Systems, Inc.(a)		9,291		414,750
Cornerstone OnDemand, Inc.(a)		2,633		154,162
Dassault Systemes SE		301		49,643
Dropbox, Inc., Class A(a)		3,046		54,554
Five9, Inc.(a)		1,379		90,435
Fortinet, Inc.(a)		101		10,783
Intuit, Inc.		4,161		1,089,891

SCHEDULE OF INVESTMENTS 15

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Software (continued)
Manhattan Associates, Inc.(a)		1,745	$	139,164
Microsoft Corp.		50,904		8,027,561
Model N, Inc.(a)		3,978		139,508
Oracle Corp.		5,990		317,350
Oracle Corp. Japan		100		9,076
Paycom Software, Inc.(a)		57		15,091
Paylocity Holding Corp.(a)(b)		11,320		1,367,682
PROS Holdings, Inc.(a)(b)		974		58,362
Q2 Holdings, Inc.(a)(b)		1,103		89,431
Rapid7, Inc.(a)		2,197		123,076
RingCentral, Inc., Class A(a)(b)		4,587		773,689
Sage Group PLC		605		6,002
salesforce.com, Inc.(a)		7,830		1,273,471
SAP SE		1,868		251,429
ServiceNow, Inc.(a)(b)		2,838		801,224
Splunk, Inc.(a)		236		35,346
SPS Commerce, Inc.(a)		12,404		687,430
SVMK, Inc.(a)		6,523		116,566
Totvs SA		26,373		423,193
Tyler Technologies, Inc.(a)		55		16,501
VMware, Inc., Class A(a)		36		5,464
Workday, Inc., Class A(a)(b)		2,368		389,418
Yext, Inc.(a)(b)		19,125		275,783
				20,722,710
Specialty Retail — 1.7%
Advance Auto Parts, Inc.		1,448		231,912
America’sCar-Mart, Inc.(a)		1,097		120,297
American Eagle Outfitters, Inc.(b)		839		12,333
Asbury Automotive Group, Inc.(a)		9,008		1,007,004
AutoNation, Inc.(a)(b)		943		45,858
AutoZone, Inc.(a)		356		424,106
Best Buy Co., Inc.		3,921		344,264
CarMax, Inc.(a)		2,855		250,298
Children’s Place, Inc.		507		31,698
Designer Brands, Inc., Class A		2,029		31,937
Fast Retailing Co. Ltd.		100		59,407
Five Below, Inc.(a)		27		3,452
Home Depot, Inc.		13,485		2,944,854
Home Product Center PCL — NVDR		552,800		294,820
Industria de Diseno Textil SA		1,771		62,588
JUMBO SA		2,026		42,156
Lithia Motors, Inc., Class A		1,971		289,737
Lowe’s Cos., Inc.		7,605		910,775
MarineMax, Inc.(a)		7,616		127,111
O’Reilly Automotive, Inc.(a)		1,269		556,152
Ross Stores, Inc.(b)		660		76,837
Shoe Carnival, Inc.(b)		1,767		65,874
Signet Jewelers Ltd.(b)		4,267		92,765
Sonic Automotive, Inc., Class A(b)		9,322		288,982
Tilly’s, Inc., Class A		5,473		67,044
Tractor Supply Co.		232		21,678
Zumiez, Inc.(a)		5,350		184,789
				8,588,728
Technology Hardware, Storage & Peripherals — 2.7%
Acer, Inc.		354,000		210,992
Apple, Inc.		29,656		8,708,484
Asustek Computer, Inc.		44,000		339,586
Chicony Electronics Co. Ltd.		32,000		95,094
HP, Inc.		6,956		142,946
Lenovo Group Ltd.		782,000		525,155
Pegatron Corp.		66,000		150,936
Quanta Computer, Inc.		230,000		494,066
Samsung Electronics Co. Ltd.		62,764		3,024,399

Security	Shares		Value
Technology Hardware, Storage & Peripherals (continued)
Simplo Technology Co. Ltd.		9,000	$	91,120
				13,782,778
Textiles, Apparel & Luxury Goods — 0.9%
adidas AG		142		46,160
ANTA Sports Products Ltd.		21,000		188,017
Arvind Ltd.		13,505		7,561
Bosideng International Holdings Ltd.		70,000		25,252
Cie Financiere Richemont SA, Registered Shares		88		6,877
Crocs, Inc.(a)		10,770		451,155
EssilorLuxottica SA		201		30,729
Feng TAY Enterprise Co. Ltd.		12,100		78,753
G-III Apparel Group Ltd.(a)(b)		5,193		173,966
Hermes International		189		141,581
Kering SA		131		86,318
Li Ning Co. Ltd.		260,000		779,814
Lululemon Athletica, Inc.(a)		849		196,688
LVMH Moet Hennessy Louis Vuitton SE		405		188,711
NIKE, Inc., Class B(b)		11,248		1,139,535
Oxford Industries, Inc.(b)		9,171		691,677
Ralph Lauren Corp.(b)		1,072		125,660
Steven Madden Ltd.(b)		5,532		237,931
Swatch Group AG, Bearer Shares		8		2,234
Wolverine World Wide, Inc.(b)		5,382		181,589
				4,780,208
Thrifts & Mortgage Finance — 0.8%
Entegra Financial Corp.(a)		119		3,589
Essent Group Ltd.		15,250		792,848
Federal Agricultural Mortgage Corp., Class C		2,997		250,250
Housing Development Finance Corp. Ltd.		30,701		1,038,076
Merchants Bancorp(b)		7,933		156,359
OceanFirst Financial Corp.		13,812		352,759
Radian Group, Inc.		12,890		324,312
Riverview Bancorp, Inc.		46,822		384,409
Timberland Bancorp, Inc.		1,091		32,446
United Community Financial Corp.		10,134		118,162
Washington Federal, Inc.		12,142		445,004
				3,898,214
Tobacco — 0.3%
Altria Group, Inc.		7,504		374,525
Gudang Garam Tbk PT		63,900		243,756
ITC Ltd.		137,531		458,092
Philip Morris International, Inc.		2,632		223,957
Vector Group Ltd.		5,013		67,124
				1,367,454
Trading Companies & Distributors — 0.8%
Applied Industrial Technologies, Inc.(b)		9,839		656,163
Ashtead Group PLC		1,327		42,430
Barloworld Ltd.		33,450		269,229
Beacon Roofing Supply, Inc.(a)		1,126		36,010
BMC Stock Holdings, Inc.(a)		18,771		538,540
Brenntag AG		230		12,479
Fastenal Co.		324		11,972
Ferguson PLC		793		72,168
Foundation Building Materials, Inc.(a)(b)		12,543		242,707
GATX Corp.(b)		5,857		485,252
GMS, Inc.(a)(b)		6,363		172,310
H&E Equipment Services, Inc.		12,040		402,497
Herc Holdings, Inc.(a)(b)		6,370		311,748
ITOCHU Corp.		3,700		85,754
Marubeni Corp.		6,800		50,241
Mitsubishi Corp.		4,500		119,211
Mitsui & Co. Ltd.		500		8,888

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Trading Companies & Distributors (continued)
Posco International Corp.		4,483	$	72,118
Rush Enterprises, Inc., Class A		4,602		213,993
SiteOne Landscape Supply, Inc.(a)		224		20,306
Sumitomo Corp.		4,800		71,296
Titan Machinery, Inc.(a)		3,677		54,346
Toyota Tsusho Corp.		600		21,077
W.W. Grainger, Inc.		25		8,463
Watsco, Inc.		82		14,772
				3,993,970
Transportation Infrastructure — 0.3%
Aena SME SA(c)		478		91,641
Aeroports de Paris		536		106,125
Atlantia SpA		1,842		42,990
Auckland International Airport Ltd.		3,058		18,025
DP World PLC		3,095		40,573
Fraport AG Frankfurt Airport Services Worldwide		272		23,089
Grupo Aeroportuario del Centro Norte SAB de CV		51,705		387,853
Grupo Aeroportuario del Centro Norte SAB de CV, ADR		1,414		84,755
Grupo Aeroportuario del Pacifico SAB de CV, ADR		2,631		312,063
Grupo Aeroportuario del Pacifico SAB de CV, Class B		36,800		437,279
Transurban Group		3,242		33,934
				1,578,327
Water Utilities — 0.1%
American States Water Co.		223		19,320
American Water Works Co., Inc.		5,335		655,405
Global Water Resources, Inc.		1,899		24,972
				699,697
Wireless Telecommunication Services — 0.7%
Advanced Info Service PCL — NVDR		17,400		123,555
America Movil SAB de CV, Series L		606,569		484,421
Boingo Wireless, Inc.(a)		1,809		19,809
China Mobile Ltd.		110,000		929,484
Etihad Etisalat Co.(a)		10,447		69,610
Gogo, Inc.(a)		3,675		23,520
KDDI Corp.		1,800		53,705
Maxis Bhd		95,100		123,810
Mobile TeleSystems PJSC — ADR		9,288		94,273
NTT DOCOMO, Inc.		500		13,928
Sistema JSFC		257,977		63,453
SoftBank Group Corp.		1,900		82,492
Sprint Corp.(a)		41,214		214,725
T-Mobile U.S., Inc.(a)		5,567		436,564
Telephone & Data Systems, Inc.		10,467		266,176
Turkcell Iletisim Hizmetleri AS		22,361		51,862
United States Cellular Corp.(a)		6,074		220,061
Vodafone Group PLC		34,012		66,030
				3,337,478
Total Common Stocks — 87.4% (Cost — $376,267,463)				443,306,131
Preferred Stocks — 0.8%
Banks — 0.8%
Banco Bradesco SA, Preference Shares, 0.00%(a)		279,137		2,509,853
Itau Unibanco Holding SA, Preference Shares, 0.00%		168,741		1,556,241
				4,066,094
Health Care Equipment & Supplies — 0.0%
Sartorius AG, Preference Shares, 0.00%		26		5,558
Household Products — 0.0%
Henkel AG & Co. KGaA, Preference Shares, 0.00%		87		8,987

Security	Shares		Value
Metals & Mining — 0.0%
Gerdau SA, Preference Shares, 0.00%		24,360	$	121,113
Oil, Gas & Consumable Fuels — 0.0%
Petroleo Brasileiro SA, Preference Shares, 0.00%		10,100		75,774
Total Preferred Stocks — 0.8% (Cost — $3,783,504)				4,277,526
Rights — 0.0%
Metals & Mining — 0.0%
Pan American Silver Corp., (Expires 02/22/29)(a)(d)		16,660		3,499
Oil, Gas & Consumable Fuels — 0.0%
Repsol SA, (Expires 01/21/20)(a)		3,312		1,571
Pharmaceuticals — 0.0%
Bristol-Myers Squibb Co., (Expires 03/31/21)(a)		4,640		13,966
Total Rights — 0.0% (Cost — $14,989)				19,036
Total Long-Term Investments — 88.2% (Cost — $380,065,956)				447,602,693
Short-Term Securities — 15.4%
BlackRock Cash Funds: Institutional, SL Agency Shares, 1.84%(e)(f)(g)		34,053,507		34,067,128
BlackRock Cash Funds: Treasury, SL Agency Shares, 1.52%(f)(g)		43,836,183		43,836,183
Total Short-Term Securities — 15.4% (Cost — $77,898,420)				77,903,311
Total Investments — 103.6% (Cost — $457,964,376)				525,506,004
Liabilities in Excess of Other Assets — (3.6)%				(18,368,036	)
Net Assets — 100.0%			$	507,137,968

^(a)  Non-income producing security.

^(b)  Security, or a portion of the security, is on loan.

^(c)  Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

^(d)  Security is valued using significant unobservable inputs and is classified as Level 3 in the fair value hierarchy.

^(e)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(f)  Annualized7-day yield as of period end.

SCHEDULE OF INVESTMENTS 17

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio

^(g)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliate	Shares Held at 12/31/18		Net Activity		Shares Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss) (a)		Change in Unrealized Appreciation (Depreciation)
BlackRock Cash Funds: Institutional, SL Agency Shares		29,237,013		4,816,494		34,053,507	$	34,067,128	$	135,153	(b)	$	4,137	$	3,959
BlackRock Cash Funds: Treasury, SL Agency Shares		24,397,577		19,438,606		43,836,183		43,836,183		798,965			—		—
							$	77,903,311	$	934,118		$	4,137	$	3,959

^(a)  Includes net capital gain distributions, if applicable.

^(b)  Represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

For Master Portfolio compliance purposes, the Master Portfolio’s industry classifications refer to one or more of the industry sub-classifications used by one or more widely recognized market indexes or rating group indexes, and/or as defined by the investment adviser. These definitions may not apply for purposes of this report, which may combine such industry sub-classifications for reporting ease.

Derivative Financial Instruments Outstanding as of Year End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
MSCI Emerging Markets Index		47		03/20/20	$	2,632	$	63,536
Russell 2000E-Mini Index		12		03/20/20		1,002		10,573
S&P 500E-Mini Index		1,802		03/20/20		291,122		8,284,791
								8,358,900
Short Contracts
MSCI EAFE Index		253		03/20/20		25,762		(682,282	)
MSCI Emerging MarketsE-Mini Index		2,020		03/20/20		113,140		(6,681,668	)
Russell 2000E-Mini Index		1,160		03/20/20		96,895		(1,992,568	)
								(9,356,518	)
							$	(997,618	)

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statement of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instruments
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	8,358,900	$	—	$	—	$	—	$	8,358,900
Liabilities — Derivative Financial Instruments
Futures contracts
Unrealized depreciation on futures contracts(a)	$	—	$	—	$	9,356,518	$	—	$	—	$	—	$	9,356,518

^(a) Net cumulative unrealized appreciation (depreciation) on futures contracts, if any, are reported in the Schedule of Investments. In Statement of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in net unrealized appreciation (depreciation).

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio

Derivative Financial Instruments Categorized by Risk Exposure (continued)

For the year ended December 31, 2019, the effect of derivative financial instruments in the Statement of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Futures contracts	$	—	$	—	$	25,804,744	$	—	$	—	$	—	$	25,804,744
Net Change in Unrealized Appreciation (Depreciation) on:
Futures contracts	$	—	$	—	$	3,214,066	$	—	$	—	$	—	$	3,214,066

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	260,227,199
Average notional value of contracts — short	$	204,932,945

For more information about the Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Common Stocks:
Aerospace & Defense	$	4,202,146	$	45,725	$	—	$	4,247,871
Air Freight & Logistics		2,708,558		118,649		—		2,827,207
Airlines		4,224,825		—		—		4,224,825
Auto Components		2,075,501		416,528		—		2,492,029
Automobiles		1,793,669		1,817,591		—		3,611,260
Banks		21,364,400		12,310,916		—		33,675,316
Beverages		6,248,686		1,788,634		—		8,037,320
Biotechnology		15,720,882		731,382		3,470		16,455,734
Building Products		1,989,487		244,459		—		2,233,946
Capital Markets		9,007,563		1,571,712		—		10,579,275
Chemicals		7,258,965		1,520,748		—		8,779,713
Commercial Services & Supplies		3,648,330		225,369		—		3,873,699
Communications Equipment		2,009,236		116,783		—		2,126,019
Construction & Engineering		2,333,400		2,085,985		—		4,419,385
Construction Materials		778,121		1,231,029		—		2,009,150
Consumer Finance		3,161,733		280,280		—		3,442,013
Containers & Packaging		195,260		—		—		195,260
Distributors		266,673		30,428		—		297,101
Diversified Consumer Services		1,890,573		—		—		1,890,573
Diversified Financial Services		2,156,860		1,505,051		—		3,661,911
Diversified Telecommunication Services		3,908,138		1,390,012		—		5,298,150
Electric Utilities		4,495,416		890,920		—		5,386,336
Electrical Equipment		1,690,718		757,610		—		2,448,328
Electronic Equipment, Instruments & Components		3,984,056		3,342,201		—		7,326,257
Energy Equipment & Services		1,859,777		23,589		—		1,883,366
Entertainment		3,224,472		316,906		—		3,541,378
Equity Real Estate Investment Trusts (REITs)		15,018,335		323,028		—		15,341,363
Food & Staples Retailing		4,633,572		958,212		—		5,591,784
Food Products		5,121,289		2,781,392		—		7,902,681
Gas Utilities		1,378,845		2,142,630		—		3,521,475
Health Care Equipment & Supplies		7,697,156		651,806		—		8,348,962
Health Care Providers & Services		8,830,176		806,947		—		9,637,123
Health Care Technology		2,847,943		24,124		—		2,872,067
Hotels, Restaurants & Leisure		6,899,180		732,989		—		7,632,169

SCHEDULE OF INVESTMENTS 19

Schedule of Investments  (continued) December 31, 2019 Active Stock Master Portfolio

Fair Value Hierarchy as of Period End (continued)

	Level 1			Level 2		Level 3		Total
Household Durables	$	2,994,456		$	1,030,245	$	—	$	4,024,701
Household Products		3,511,985			644,072		—		4,156,057
Independent Power and Renewable Electricity Producers		180,433			53,087		—		233,520
Industrial Conglomerates		1,215,686			757,764		—		1,973,450
Insurance		7,413,635			5,652,682		—		13,066,317
Interactive Media & Services		12,083,428			5,321,271		—		17,404,699
Internet & Direct Marketing Retail		16,088,847			811,645		—		16,900,492
IT Services		15,247,838			1,518,244		—		16,766,082
Leisure Products		305,200			—		—		305,200
Life Sciences Tools & Services		2,100,241			50,625		—		2,150,866
Machinery		7,557,793			3,168,438		—		10,726,231
Marine		31,176			310,877		—		342,053
Media		3,344,819			247,846		—		3,592,665
Metals & Mining		4,227,055			5,538,719		—		9,765,774
Mortgage Real Estate Investment Trusts (REITs)		975,102			—		—		975,102
Multi-Utilities		2,004,727			105,087		—		2,109,814
Multiline Retail		807,170			—		—		807,170
Oil, Gas & Consumable Fuels		12,251,769			7,874,639		—		20,126,408
Paper & Forest Products		1,218,753			—		—		1,218,753
Personal Products		1,159,593			934,095		—		2,093,688
Pharmaceuticals		15,727,601			3,726,823		—		19,454,424
Professional Services		3,185,112			576,858		—		3,761,970
Real Estate Management & Development		733,170			1,312,928		—		2,046,098
Road & Rail		2,291,093			221,742		—		2,512,835
Semiconductors & Semiconductor Equipment		9,094,826			9,136,326		—		18,231,152
Software		20,406,560			316,150		—		20,722,710
Specialty Retail		8,171,913			416,815		—		8,588,728
Technology Hardware, Storage & Peripherals		8,851,430			4,931,348		—		13,782,778
Textiles, Apparel & Luxury Goods		3,244,361			1,535,847		—		4,780,208
Thrifts & Mortgage Finance		2,860,138			1,038,076		—		3,898,214
Tobacco		665,606			701,848		—		1,367,454
Trading Companies & Distributors		3,438,308			555,662		—		3,993,970
Transportation Infrastructure		1,221,950			356,377		—		1,578,327
Water Utilities		699,697			—		—		699,697
Wireless Telecommunication Services		1,759,549			1,577,929		—		3,337,478
Preferred Stocks		4,262,981			14,545		—		4,277,526
Rights		15,537			—		3,499		19,036
Short-Term Securities		77,903,311			—		—		77,903,311
	$	423,876,790		$	101,622,245	$	6,969	$	525,506,004
Derivative Financial Instruments(a)
Assets:
Equity contracts	$	8,358,900		$	—	$	—	$	8,358,900
Liabilities:
Equity contracts		(9,356,518	)		—		—		(9,356,518	)
	$	(997,618	)	$	—	$	—	$	(997,618	)

^(a)  Derivative financial instruments are futures contracts. Futures contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	Active Stock Master Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $33,274,990, cost — $380,065,956)	$	447,602,693
Investments at value — affiliated (cost — $77,898,420)		77,903,311
Cash pledged for futures contracts		17,270,000
Foreign currency at value (cost — $787,658)		798,762
Receivables:
Investments sold		9,972
Securities lending income — affiliated		13,378
Dividends — affiliated		55,945
Dividends — unaffiliated		720,550
Variation margin on futures contracts		703,074
Prepaid expenses		5,744
Total assets		545,083,429
LIABILITIES
Cash collateral on securities loaned at value		34,064,801
Payables:
Administration fees		83,655
Deferred foreign capital gain tax		11,255
Trustees’ fees		3,743
Investment advisory fees		40,391
Other accrued expenses		22,820
Variation margin on futures contracts		563,875
Withdrawals to investors		3,154,921
Total liabilities		37,945,461
NET ASSETS	$	507,137,968
NET ASSETS CONSIST OF
Investors’ capital	$	440,594,622
Net unrealized appreciation (depreciation)		66,543,346
NET ASSETS	$	507,137,968

See notes to financial statements.

FINANCIAL STATEMENTS 21

Statement of Operations

Year Ended December 31, 2019

	Active Stock Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	798,965
Dividends — unaffiliated		8,493,899
Interest — unaffiliated		261,527
Securities lending income — affiliated — net		135,153
Foreign taxes withheld		(399,165	)
Total investment income		9,290,379
EXPENSES
Investment advisory		1,161,050
Administration		464,420
Professional		22,903
Trustees		17,564
Total expenses		1,665,937
Less:
Fees waived and/or reimbursed by the Manager		(508,390	)
Fees waived and/or reimbursed by the Administrator		(464,420	)
Total expenses after fees waived and/or reimbursed		693,127
Net investment income		8,597,252
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Futures contracts		25,804,744
Foreign currency transactions		(140,485	)
Investments — affiliated		4,137
Investments — unaffiliated (including $141,131 foreign capital gain tax)		19,812,363
		45,480,759
Net change in unrealized appreciation (depreciation) on:
Futures contracts		3,214,066
Foreign currency translations		11,710
Investments — affiliated		3,959
Investments — unaffiliated (including $32,657 foreign capital gain tax)		72,114,450
		75,344,185
Net realized and unrealized gain		120,824,944
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	129,422,196

See notes to financial statements.

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	Active Stock Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	8,597,252		$	9,668,652
Net realized gain		45,480,759			45,014,797
Net change in unrealized appreciation (depreciation)		75,344,185			(66,244,769	)
Net increase (decrease) in net assets resulting from operations		129,422,196			(11,561,320	)
CAPITAL TRANSACTIONS
Proceeds from contributions		76,298,543			28,030,716
Value of withdrawals		(127,680,923	)		(122,827,185	)
Net decrease in net assets derived from capital transactions		(51,382,380	)		(94,796,469	)
NET ASSETS
Total increase (decrease) in net assets		78,039,816			(106,357,789	)
Beginning of year		429,098,152			535,455,941
End of year	$	507,137,968		$	429,098,152

See notes to financial statements.

FINANCIAL STATEMENTS 23

Financial Highlights

	Active Stock Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		31.98	%		(3.90	)%		22.15	%		12.45	%		(1.20	)%
Ratios to Average Net Assets
Total expenses		0.36	%(a)		0.36	%		0.36	%		0.36	%		0.35	%
Total expenses after fees waived and/or reimbursed		0.15	%(a)		0.15	%		0.15	%		0.15	%		0.15	%
Net investment income		1.85	%(a)		1.88	%		1.69	%		1.66	%		1.65	%
Supplemental Data
Net assets, end of year (000)	$	507,138		$	429,098		$	535,456		$	503,047		$	445,996
Portfolio turnover rate		172	%		150	%		252	%		115	%		132	%

^(a)  Excludes expenses incurred indirectly as a result of investments in underlying funds of 0.01%.

See notes to financial statements.

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. Active Stock Master Portfolio (the “Master Portfolio”) is a series of MIP. The Master Portfolio is classified as diversified.

The Master Portfolio, together with certain other registered investment companies advised by BlackRock Fund Advisors (the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the Master Portfolio is informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain. Interest income, including amortization and accretion of premiums and discounts on debt securities is recognized on an accrual basis.

Foreign Currency Translation:The Master Portfolio’s books and records are maintained in U.S. dollars. Securities and other assets and liabilities denominated in foreign currencies are translated into U.S. dollars using exchange rates determined as of the close of trading on the New York Stock Exchange (“NYSE”). Purchases and sales of investments are recorded at the rates of exchange prevailing on the respective dates of such transactions. Generally, when the U.S. dollar rises in value against a foreign currency, the investments denominated in that currency will lose value; the opposite effect occurs if the U.S. dollar falls in relative value.

The Master Portfolio does not isolate the portion of the results of operations arising as a result of changes in the exchange rates from the changes in the market prices of investments held or sold for financial reporting purposes. Accordingly, the effects of changes in exchange rates on investments are not segregated in the Statement of Operations from the effects of changes in market prices of those investments, but are included as a component of net realized and unrealized gain (loss) from investments. The Master Portfolio reports realized currency gains (losses) on foreign currency related transactions as components of net realized gain (loss) for financial reporting purposes, whereas such components are generally treated as ordinary income for U.S. federal income tax purposes.

Segregation and Collateralization:In cases where the Master Portfolio enters into certain investments (e.g., futures contracts) that would be treated as “senior securities” for 1940 Act purposes, the Master Portfolio may segregate or designate on itsbooks and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the Master Portfolio may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, the Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. The Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Master Portfolio, which cannot be predicted with any certainty.

Other: Expenses directly related to the Master Portfolio are charged to the Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the NYSE (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board of Trustees of MIP (the “Board”). The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of the Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

Generally, trading in foreign instruments is substantially completed each day at various times prior to the close of trading on the NYSE. Occasionally, events affecting the values of such instruments may occur between the foreign market close and the close of trading on the NYSE that may not be reflected in the

NOTESTO FINANCIAL STATEMENTS 25

Notes to Financial Statements  (continued)

computation of the Master Portfolio’s net assets. Each business day, the Master Portfolio uses a pricing service to assist with the valuation of certain foreign exchange-traded equity securities and foreign exchange-traded andover-the-counter (“OTC”) options (the “Systematic Fair Value Price”). Using current market factors, the Systematic Fair Value Price is designed to value such foreign securities and foreign options at fair value as of the close of trading on the NYSE, which follows the close of the local markets.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that the Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

For investments in equity or debt issued by privately held companies or funds (“Private Company” or collectively, the “Private Companies”) and other Fair Valued Investments, the fair valuation approaches that are used by the Global Valuation Committee and third party pricing services utilize one or a combination of, but not limited to, the following inputs.

	Standard Inputs Generally Considered By Third Party Pricing Services
Market approach	(i)  recent market transactions, including subsequent rounds of financing, in the underlying investment or comparable issuers; (ii) recapitalizations and other transactions across the capital structure; and (iii)   market multiples of comparable issuers.
Income approach	(i)  future cash flows discounted to present and adjusted as appropriate for liquidity, credit, and/or market risks; (ii) quoted prices for similar investments or assets in active markets; and (iii)   other risk factors, such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks, recovery rates, liquidation amounts and/or default rates.
Cost approach	(i)  audited or unaudited financial statements, investor communications and financial or operational metrics issued by the Private Company; (ii) changes in the valuation of relevant indices or publicly traded companies comparable to the Private Company; (iii)   relevant news and other public sources; and (iv)   known secondary market transactions in the Private Company’s interests and merger or acquisition activity in companies comparable to the Private Company.

Investments in series of preferred stock issued by Private Companies are typically valued utilizing market approach in determining the enterprise value of the company. Such investments often contain rights and preferences that differ from other series of preferred and common stock of the same issuer. Valuation techniques such as an option pricing model (“OPM”), a probability weighted expected return model (“PWERM”) or a hybrid of those techniques are used in allocating enterprise value of the company, as deemed appropriate under the circumstances. The use of OPM and PWERM techniques involve a determination of the exit scenarios of the investment in order to appropriately allocate the enterprise value of the company among the various parts of its capital structure.

The Private Companies are not subject to the public company disclosure, timing, and reporting standards as other investments held by a Trust. Typically, the most recently available information by a Private Company is as of a date that is earlier than the date a Trust is calculating its NAV. This factor may result in a difference between the value of the investment and the price a Trust could receive upon the sale of the investment.

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by privately held companies or funds. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

4. SECURITIES AND OTHER INVESTMENTS

Preferred Stocks:Preferred stock has a preference over common stock in liquidation (and generally in receiving dividends as well), but is subordinated to the liabilities of the issuer in all respects. As a general rule, the market value of preferred stock with a fixed dividend rate and no conversion element varies inversely with interest rates and perceived credit risk, while the market price of convertible preferred stock generally also reflects some element of conversion value. Because preferred stock is junior to debt securities and other obligations of the issuer, deterioration in the credit quality of the issuer will cause greater changes in the value of a preferred stock than in a more senior debt security with similar stated yield characteristics. Unlike interest payments on debt securities, preferred stock dividends are payable only if declared by the issuer’s board of directors. Preferred stock also may be subject to optional or mandatory redemption provisions.

Securities Lending:The Master Portfolio may lend its securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the Master Portfolio collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by the Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the Master Portfolio and any additional required collateral is delivered to the Master Portfolio, or excess collateral returned by the Master Portfolio, on the next business day. During the term of the loan, the Master Portfolio is entitled to all distributions made on or in respect of the loaned securities, but does not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as common stocks in the Master Portfolio’s Schedule of Investments, and the value of any related collateral are shown separately in the Statement of Assets and Liabilities as a component of investments at value-unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedule of Investments.

Securities lending transactions are entered into by the Master Portfolio under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the Master Portfolio, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and the Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the Master Portfolio’s securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount (b)
Barclays Bank PLC	$	1,473,793	$	(1,473,793	)	$	—
BNP Paribas S.A.		3,800,557		(3,800,557	)		—
Bank of America N.A.		695,194		(695,194	)		—
Citigroup Global Markets Inc.		1,340,962		(1,340,962	)		—
Credit Suisse Securities (USA) LLC		3,797,279		(3,797,279	)		—
Deutsche Bank Securities Inc.		14,126		(14,126	)		—
Goldman Sachs & Co.		1,303,788		(1,303,788	)		—
HSBC Bank PLC		1,075,955		(1,075,955	)		—
ING Financial Markets LLC		140,091		(140,091	)		—
Jefferies LLC		375,650		(375,650	)		—
JP Morgan Securities LLC		5,123,356		(5,123,356	)		—
Morgan Stanley		5,905,649		(5,905,649	)		—
National Financial Services LLC		273,387		(273,387	)		—
Scotia Capital (USA) Inc.		1,264,625		(1,264,625	)		—
Toronto-Dominion Bank		534,586		(524,626	)		9,960
UBS AG		4,570,210		(4,570,210	)		—
Virtu Americas LLC		1,195,861		(1,195,861	)		—
Wells Fargo Securities LLC		389,921		(389,921	)		—
	$	33,274,990	$	(33,265,030	)	$	9,960

^(a)  Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by Master Portfolio is disclosed in the Master Portfolio’s Statement of Assets and Liabilities.

^(b)  The market value of the loaned securities is determined as of December 31, 2019. Additional collateral is delivered to the Master Portfolio on the next business day in accordance with the MSLA. The net amount would be subject to the borrower default indemnity in the event of default by the counterparty.

NOTESTO FINANCIAL STATEMENTS 27

Notes to Financial Statements  (continued)

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the Master Portfolio benefits from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”). BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. The Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the Master Portfolio.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The Master Portfolio engages in various portfolio investment strategies using derivative contracts both to increase the returns of the Master Portfolio and/or to manage its exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedule of Investments. These contracts may be transacted on an exchange or OTC.

Futures Contracts: Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

Futures contracts are agreements between the Master Portfolio and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the Master Portfolio is required to deposit initial margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statement of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedule of Investments and cash deposited, if any, are shown as cash pledged for futures contracts in the Statement of Assets and Liabilities. Pursuant to the contract, the Master Portfolio agrees to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statement of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statement of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the Master Portfolio, entered into an Investment Advisory Agreement with the Manager, the Master Portfolio’s investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of the Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Master Portfolio.

For such services, the Master Portfolio pays the Manager a monthly fee at an annual rate equal to the following percentages of the average daily value of the Master Portfolio’s net assets.

Average Daily Net Assets	Investment Advisory Fee
First $1 Billion		0.25	%
$1 Billion — $3 Billion		0.24
$3 Billion — $5 Billion		0.23
$5 Billion — $10 Billion		0.22
Greater than $10 Billion		0.21

Administration: MIP, on behalf of the Master Portfolio, entered into an Administration Agreement with BlackRock Advisors, LLC (“BAL” or the “Administrator”), which has agreed to provide general administrative services (other than investment advice and related portfolio activities). BAL has agreed to bear all of the Master Portfolio’s ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Master Portfolio. BAL is entitled to receive for these administrative services an annual fee of 0.10% based on the average daily net assets of the Master Portfolio.

From time to time, BAL may waive such fees in whole or in part. Any such waiver will reduce the expenses of the Master Portfolio and, accordingly, have a favorable impact on its performance. BAL may delegate certain of its administration duties tosub-administrators.

Expense Waivers and Reimbursements:The Manager has voluntarily agreed to waive a portion of the investment advisory fees payable by the Master Portfolio. This voluntary waiver may be terminated at any time. This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the Manager waived $441,199 pursuant to this arrangement.

BAL voluntarily agreed to waive a portion of its administration fees payable by the Master Portfolio. This arrangement is voluntary and may be terminated by BAL at any time. This amount is included in fees waived and/or reimbursed by the Administrator in the Statement of Operations. For the year ended December 31, 2019, the amount waived was $464,420.

The fees and expenses of MIP’s trustees who are not “interested persons” of MIP, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and MIP’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Master Portfolio. BAL has contractually

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

agreed to reimburse the Master Portfolio or provide an offsetting credit against these administration fees paid by the Master Portfolio in an amount equal to the independent expenses through April 30, 2020. For the year ended December 31, 2019, the amount waived was $40,470.

With respect to the Master Portfolio, the Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees the Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the amount waived was $26,721.

The Manager has contractually agreed to waive its investment advisory fee with respect to any portion of the Master Portfolio’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through April 30, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees or by a vote of a majority of the outstanding voting securities of the Master Portfolio. For the year ended December 31, 2019, there were no fees waived and/or reimbursed by the Manager pursuant to this arrangement.

Securities Lending:The U.S. Securities and Exchange Commission (“SEC”) has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities lending. The Master Portfolio is responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the Master Portfolio bears to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a 90 day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, the Master Portfolio retains 73.5% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, the Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 80% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Statement of Operations. For the year ended December 31, 2019, the Master Portfolio paid BTC $40,184 in total for securities lending agent services.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, the Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Master Portfolio’s investment policies and restrictions. The Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of MIP are directors and/or officers of BlackRock or its affiliates.

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments excluding short-term securities, were $703,913,478 and $722,548,219, respectively.

8. INCOME TAX INFORMATION

The Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

NOTESTO FINANCIAL STATEMENTS 29

Notes to Financial Statements  (continued)

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

Tax Cost	$	462,717,387
Gross unrealized appreciation	$	82,765,756	��
Gross unrealized depreciation		(19,977,139	)
Net unrealized appreciation	$	62,788,617

9. BANK BORROWINGS

MIP, on behalf of the Master Portfolio, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the Master Portfolio may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the Master Portfolio, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of (a)one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statement of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the Master Portfolio did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, the Master Portfolio invests in securities or other instruments and may enter into certain transactions, and such activities subject the Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. The Master Portfolio’s prospectus provides details of the risks to which the Master Portfolio is subject.

The Master Portfolio may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk: The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. The Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that the Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. The Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause the Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of the Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which the Master Portfolio invests.

Counterparty Credit Risk:The Master Portfolio may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolio manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Master Portfolio to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolio’s exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Master Portfolio.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

With exchange-traded futures, there is less counterparty credit risk to the Master Portfolio since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, the Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists inexchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Master Portfolio.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolio through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of

Master Investment Portfolio and Investors of Active Stock Master Portfolio

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Active Stock Master Portfolio (one of the series constituting Master Investment Portfolio, referred to hereafter as the “Master Portfolio”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Master Portfolio as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Master Portfolio’s management. Our responsibility is to express an opinion on the Master Portfolio’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolio in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM 31

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of Master Investment Portfolio (“MIP”), on behalf of Active Stock Master Portfolio, met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions. During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions. During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements. The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”)  Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019) and Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

TRUSTEEAND OFFICER INFORMATION 33

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”)  Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”)  Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015) President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc.,55 East 52nd Street, New York, New York 10055. (b) Independent Trustees serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate. (c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015. (d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex. (e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

TRUSTEEAND OFFICER INFORMATION 35

Trustee and Officer Information  (continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Officers of MIP serve at the pleasure of the Board.

Further information about MIP’s Trustees and Officers is available in MIP’s Statement of Additional Information, which can be obtained without charge by calling (800)441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of MIP.

Investment Adviser

BlackRock Fund Advisors

San Francisco, CA 94105

Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of MIP

400 Howard Street

San Francisco, CA 94105

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Additional Information

General Information

Householding

The Master Portfolio will mail only one copy of shareholder documents, including prospectuses, annual and semi-annual reports and proxy statements, to shareholders with multiple accounts at the same address. This practice is commonly called “householding” and is intended to reduce expenses and eliminate duplicate mailings of shareholder documents. Mailings of your shareholder documents may be householded indefinitely unless you instruct us otherwise. If you do not want the mailing of these documents to be combined with those for other members of your household, please call the Master Portfolio at (800) 441-7762.

Availability of Quarterly Schedule of Investments

The Master Portfolio files its complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports onForm N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information on Form N-Q. The Master Portfolio’s Forms N-PORT and N-Q are available on the SEC’s website at sec.gov. The Master Portfolio’s Form N-Q may also be obtained upon request and without charge by calling(800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Master Portfolio uses to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling (800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Master Portfolio voted proxies relating to securities held in the Master Portfolio’s portfolio during the most recent 12-month period ended June 30 is available upon request and without charge (1) atblackrock.com or by calling (800) 441-7762; and (2) on the SEC’s website at sec.gov.

Glossary of Terms Used in this Report

ADR	American Depositary Receipts
GDR	Global Depositary Receipt
NVDR	Non-voting Depository Receipts
PCL	Public Company Limited
REIT	Real Estate Investment Trust
S&P	Standard & Poor’s

ADDITIONAL INFORMATION / GLOSSARYOF TERMS USEDINTHIS REPORT 37

Portfolio Information  as of December 31, 2019 International Tilts Master Portfolio

TEN LARGEST HOLDINGS

Security	Percent of Net Assets
Roche Holding AG		2	%
Novartis AG, Registered Shares		2
LVMH Moet Hennessy Louis Vuitton SE		2
SAP SE		2
Nestle SA, Registered Shares		2
GlaxoSmithKline PLC		1
Allianz SE, Registered Shares		1
HSBC Holdings PLC		1
L’Oreal SA		1
Diageo PLC		1

GEOGRAPHIC ALLOCATION

Country	Percent of Net Assets
Japan		22	%
United Kingdom		15
France		12
Switzerland		10
Germany		10
Australia		8
Netherlands		6
United States		3
Sweden		2
Denmark		2
Finland		2
Spain		2
Hong Kong		2
Belgium		1
Italy		1
Other(a)		2
Other Assets Less Liabilities		—	(b)

^(a)  Other includes a less than 1% investment in each of the following countries: Austria, China, Ireland, Israel, Luxembourg, Singapore, Macau, Norway, New Zealand, South Africa.

^(b)  Represents less than 1% of Net Assets.

Derivative Financial Instruments

International Tilts Master Portfolio (the “Master Portfolio”) may invest in various derivative financial instruments. These instruments are used to obtain exposure to a security, commodity, index, market, and/or other assets without owning or taking physical custody of securities, commodities and/or other referenced assets or to manage market, equity, credit, interest rate, foreign currency exchange rate, commodity and/or other risks. Derivative financial instruments may give rise to a form of economic leverage and involve risks, including the imperfect correlation between the value of a derivative financial instrument and the underlying asset, possible default of the counterparty to the transaction or illiquidity of the instrument. The Master Portfolio’s successful use of a derivative financial instrument depends on the investment adviser’s ability to predict pertinent market movements accurately, which cannot be assured. The use of these instruments may result in losses greater than if they had not been used, may limit the amount of appreciation the Master Portfolio can realize on an investment and/or may result in lower distributions paid to shareholders. The Master Portfolio’s investments in these instruments, if any, are discussed in detail in the Notes to Financial Statements.

PORTFOLIO INFORMATION / DERIVATIVE FINANCIAL INSTRUMENTS 1

Schedule of Investments   December 31, 2019 International Tilts Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Common Stocks — 96.5%
Australia — 7.7%
AGL Energy Ltd.(a)		18,072	$	260,121
ALS Ltd.		21,307		137,183
Altium Ltd.		1,559		37,987
Ansell Ltd.		17,178		349,794
Aristocrat Leisure Ltd.		64,930		1,534,241
AusNet Services		122,037		145,527
Australia & New Zealand Banking Group Ltd.		39,134		674,904
Bendigo & Adelaide Bank Ltd.		9,556		65,572
BHP Group Ltd.		46,974		1,286,256
BHP Group PLC		297		6,960
Brambles Ltd.		9,071		74,661
Carsales.com Ltd.		4,386		51,149
Challenger Ltd.		4,370		24,868
CIMIC Group Ltd.		6,210		144,380
Coca-Cola Amatil Ltd.		4,839		37,578
Cochlear Ltd.		3,450		543,741
Commonwealth Bank of Australia		20,542		1,152,361
Computershare Ltd.		19,439		229,184
Crown Resorts Ltd.		4,738		39,947
CSL Ltd.		5,245		1,016,911
Domino’s Pizza Enterprises Ltd.		606		22,274
Goodman Group		1,153		10,835
IDP Education Ltd.		17,634		212,566
Macquarie Group Ltd.		9,794		948,493
Magellan Financial Group Ltd.		6,484		259,781
Orica Ltd.		12,137		187,158
Orora Ltd.		18		40
Platinum Asset Management Ltd.		23		73
QBE Insurance Group Ltd.		6,579		59,451
REA Group Ltd.(a)		4,796		348,414
Rio Tinto PLC		3,118		184,570
Scentre Group(a)		519,185		1,397,259
Sonic Healthcare Ltd.		2,765		55,750
Spark Infrastructure Group(b)		34,941		51,223
Tabcorp Holdings Ltd.		61,609		195,861
Treasury Wine Estates Ltd.		72,128		821,591
Vicinity Centres		8,553		14,960
Westpac Banking Corp.		51,591		881,006
WiseTech Global Ltd.(a)		788		12,941
				13,477,571
Austria — 0.1%
Raiffeisen Bank International AG		1,742		43,602
Vienna Insurance Group AG Wiener Versicherung Gruppe		1,945		55,098
Wienerberger AG		4,765		141,212
				239,912
Belgium — 0.9%
Ackermans & van Haaren NV		87		13,642
Galapagos NV(c)		486		101,208
Groupe Bruxelles Lambert SA		5,149		543,327
Solvay SA		2,950		343,359
UCB SA		8,067		641,928
				1,643,464
China — 0.4%
BOC Hong Kong Holdings Ltd.		224,500		779,335
Denmark — 2.4%
Carlsberg A/S, Class B		6,281		937,351
Chr Hansen Holding A/S		15,798		1,255,426
Coloplast A/S, Class B		678		84,113
FLSmidth & Co. A/S		3,018		120,354
Genmab A/S(c)		740		164,579
GN Store Nord A/S		7,035		330,931

Security	Shares		Value
Denmark (continued)
H Lundbeck A/S		3,396	$	129,831
Novo Nordisk A/S, Class B		2,217		128,473
Novozymes A/S, Class B		263		12,870
Royal Unibrew A/S		2,767		253,454
SimCorp A/S		6,362		723,405
Tryg A/S		1,885		55,883
				4,196,670
Finland — 2.3%
Fortum OYJ		32,720		807,641
Huhtamaki OYJ		886		41,125
Kone OYJ, Class B		26,455		1,729,835
Metso OYJ		865		34,172
Nordea Bank Abp		37,458		303,042
Sampo OYJ, Class A		13,745		600,149
TietoEVRY OYJ		2,135		66,385
UPM-Kymmene OYJ		8,396		291,295
Valmet OYJ		7,149		171,432
				4,045,076
France — 11.8%
Air Liquide SA		1,460		206,985
Arkema SA		343		36,676
BNP Paribas SA		2,031		120,719
Bouygues SA		9,998		426,184
Capgemini SE		865		105,794
Christian Dior SE		2,229		1,145,686
Cie de Saint-Gobain		1,730		70,871
CNP Assurances		3,059		60,951
Credit Agricole SA		25,912		377,054
Dassault Aviation SA		55		72,181
Dassault Systemes SE		5,780		953,268
Edenred		8,286		429,417
Electricite de France SA		2,647		29,536
Engie SA		29,222		473,347
EssilorLuxottica SA		3,378		516,434
Gaztransport Et Technigaz SA		2		193
Hermes International		138		103,377
Imerys SA		1,707		72,458
Ingenico Group SA		224		24,366
Kering SA		213		140,349
Korian SA		435		20,506
L’Oreal SA		7,530		2,226,677
Lagardere SCA		14,331		312,339
Legrand SA		1,299		106,081
LVMH Moet Hennessy Louis Vuitton SE		6,239		2,907,085
Natixis SA		9,611		42,812
Nexity SA		1,020		51,267
Pernod Ricard SA		10,151		1,816,395
Peugeot SA		6,777		163,171
Publicis Groupe SA		11,002		498,846
Renault SA		6,362		302,115
Rexel SA		40,292		535,911
Rubis SCA		1,350		83,074
Safran SA		12,564		1,940,626
Sanofi		2,822		283,406
Sartorius Stedim Biotech		819		135,944
Schneider Electric SE		4,535		465,925
SCOR SE		8,374		352,510
SPIE SA		1,066		21,787
Teleperformance		1,654		404,102
TOTAL SA		27,606		1,531,871
Veolia Environnement SA		15,778		419,827
Vinci SA		6,542		728,606
Wendel SA		88		11,722
				20,728,451

2 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 International Tilts Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Germany — 9.1%
adidas AG		1,746	$	567,570
Allianz SE, Registered Shares		9,485		2,324,089
alstria officeREIT-AG		1,037		19,484
Aroundtown SA		13,734		123,356
BASF SE		9,492		715,095
Bayer AG, Registered Shares		6,454		524,688
Bayerische Motoren Werke AG		13,003		1,065,020
CANCOM SE		831		48,832
Carl Zeiss Meditec AG, Bearer Shares		1,420		180,524
CompuGroup Medical SE		2,259		161,537
Continental AG		5,398		697,585
Covestro AG(d)		460		21,404
CTS Eventim AG & Co. KGaA		3,465		217,406
Daimler AG, Registered Shares		4,716		260,721
Deutsche Pfandbriefbank AG(d)		18,415		299,918
Deutsche Post AG, Registered Shares		47,030		1,788,276
DWS Group GmbH & Co. KGaA(d)		458		16,262
Evonik Industries AG		1,625		49,631
Fielmann AG		136		10,977
Freenet AG		6,222		142,655
GEA Group AG		2,036		67,326
HeidelbergCement AG		769		55,879
Hella GmbH & Co. KGaA		351		19,397
Hochtief AG		860		109,492
Jenoptik AG		2		57
Merck KGaA		4,675		551,153
MTU Aero Engines AG		50		14,246
Puma SE		1,506		115,483
Rational AG		435		348,486
SAP SE		21,551		2,900,724
Siemens AG, Registered Shares		8,416		1,099,058
Software AG		12,417		432,329
Stroeer SE & Co. KGaA		220		17,725
TAG Immobilien AG(c)		1,537		38,172
Talanx AG(c)		395		19,549
Telefonica Deutschland Holding AG		193,041		559,524
Uniper SE		2,343		77,440
Volkswagen AG		2,184		423,008
				16,084,078
Hong Kong — 1.7%
AIA Group Ltd.		40,600		427,029
ASM Pacific Technology Ltd.		1,700		23,597
CK Asset Holdings Ltd.		8,000		57,730
CLP Holdings Ltd.		9,500		99,725
Hang Lung Group Ltd.		5,000		12,369
Henderson Land Development Co. Ltd.		39,404		193,358
HKT Trust & HKT Ltd.(b)		36,000		50,734
Hongkong Land Holdings Ltd.		109,900		632,151
Kerry Properties Ltd.		74,500		236,618
Swire Pacific Ltd., Class A		61,000		566,671
Swire Properties Ltd.		61,800		204,734
Techtronic Industries Co. Ltd.(a)		32,000		261,174
Wheelock & Co. Ltd.		47,000		313,315
				3,079,205
Ireland — 0.1%
Kingspan Group PLC		1,899		115,984
Smurfit Kappa Group PLC		1,925		74,223
UDG Healthcare PLC		6,843		73,162
				263,369
Israel — 0.1%
Bank LeumiLe-Israel BM		17,252		125,818
Delek Group Ltd.		98		14,926
First International Bank of Israel Ltd.		1,166		33,771

Security	Shares		Value
Israel (continued)
Gazit-Globe Ltd.		1,345	$	14,908
Israel Chemicals Ltd.(a)		9,734		45,969
				235,392
Italy — 0.8%
A2A SpA		17,064		32,044
Ferrari NV		7,422		1,232,316
Interpump Group SpA		1,105		35,003
Italgas SpA		5,611		34,304
Mediobanca Banca di Credito Finanziario SpA		2,388		26,293
				1,359,960
Japan — 22.4%
Advantest Corp.		1,900		107,156
AEON Financial Service Co. Ltd.		600		9,454
AGC, Inc.		8,400		300,367
Aica Kogyo Co. Ltd.		600		19,799
Aisin Seiki Co. Ltd.		1,000		37,040
Amada Holdings Co. Ltd.		24,700		280,931
Amano Corp.		400		12,189
Aozora Bank Ltd.		5,300		140,019
Astellas Pharma, Inc.		24,600		419,922
Benesse Holdings, Inc.		6,600		173,479
Calbee, Inc.		700		22,807
Canon, Inc.(a)		13,700		374,948
Central Japan Railway Co.		2,100		422,244
Chubu Electric Power Co., Inc.		9,900		139,945
Citizen Watch Co. Ltd.(a)		41,700		227,102
Dai-ichi Life Holdings, Inc.		54,000		889,935
Daicel Corp.		7,700		73,615
Daikin Industries Ltd.		4,200		592,577
Daito Trust Construction Co. Ltd.		2,300		284,225
Denka Co. Ltd.		3,200		95,128
Denso Corp.		9,100		410,977
Dentsu, Inc.		3,700		127,487
DIC Corp.		6,900		190,429
Dip Corp.		500		14,770
DMG Mori Co. Ltd.		1,300		19,890
East Japan Railway Co.		5,200		469,362
Eisai Co. Ltd.		4,400		329,234
Electric Power Development Co. Ltd.		4,500		109,227
Fancl Corp.		1,200		31,949
FANUC Corp.		200		36,933
Fast Retailing Co. Ltd.(a)		2,900		1,722,814
Fuji Electric Co. Ltd.		400		12,151
Fuji Media Holdings, Inc.		2,500		35,496
Fuji Seal International, Inc.		500		11,090
FUJIFILM Holdings Corp.		7,200		343,842
Fujikura Ltd.		2,500		10,287
Furukawa Electric Co. Ltd.		500		12,800
Glory Ltd.		1,000		30,219
GS Yuasa Corp.		1,100		23,710
Honda Motor Co. Ltd.		20,500		580,182
Hoshizaki Corp.		1,300		115,908
Idemitsu Kosan Co. Ltd.		500		13,816
Isetan Mitsukoshi Holdings Ltd.(a)		9,200		82,613
Isuzu Motors Ltd.		5,900		69,743
Izumi Co. Ltd.		2,100		75,639
Japan Airlines Co. Ltd.		8,800		273,996
Japan Post Bank Co. Ltd.		12,400		118,975
Japan Post Holdings Co. Ltd.		41,500		390,285
Japan Post Insurance Co. Ltd.		600		10,228
Japan Tobacco, Inc.		14,900		332,219
JFE Holdings, Inc.		19,500		250,213
JSR Corp.		2,600		47,561

SCHEDULES OF INVESTMENTS 3

Schedule of Investments  (continued) December 31, 2019 International Tilts Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Japan (continued)
JTEKT Corp.		15,300	$	180,740
JXTG Holdings, Inc.		152,650		692,814
Kajima Corp.		14,100		187,462
Kakaku.com, Inc.		6,400		163,412
Kaneka Corp.		8,900		285,034
Kansai Electric Power Co., Inc.		7,400		85,728
Kao Corp.		20,600		1,698,986
Kawasaki Heavy Industries Ltd.		2,100		45,899
KDDI Corp.		28,400		847,352
Kewpie Corp.		500		11,234
Keyence Corp.		1,000		351,138
Kirin Holdings Co. Ltd.		29,200		637,336
Kobe Steel Ltd.		12,300		65,905
Komatsu Ltd.(a)		6,600		158,409
Konami Holdings Corp.		1,600		65,748
Konica Minolta, Inc.		36,800		239,718
Kyowa Exeo Corp.		500		12,648
Lintec Corp.		4,300		95,729
Mabuchi Motor Co. Ltd.		700		26,429
Marubeni Corp.		31,100		229,778
Maruha Nichiro Corp.		400		10,240
Maruichi Steel Tube Ltd.		500		14,051
Mazda Motor Corp.		23,800		202,810
MEIJI Holdings Co. Ltd.		1,800		121,644
Miraca Holdings, Inc.		4,600		112,668
Mitsubishi Corp.		4,600		121,860
Mitsubishi Electric Corp.		12,500		170,196
Mitsubishi Gas Chemical Co., Inc.		17,900		272,692
Mitsubishi Heavy Industries Ltd.		9,200		356,747
Mitsubishi Motors Corp.		59,500		248,012
Mitsubishi UFJ Financial Group, Inc.		221,000		1,194,800
Mitsui Chemicals, Inc.		3,400		82,822
Mitsui Mining & Smelting Co. Ltd.		600		15,912
Mizuho Financial Group, Inc.		140,500		216,429
MS&AD Insurance Group Holdings, Inc.		23,300		769,102
Nagase & Co. Ltd.		600		8,898
NEC Corp.		2,100		86,907
NGK Spark Plug Co. Ltd.		600		11,630
Nichirei Corp.		1,100		25,696
Nidec Corp.		3,500		478,043
Nifco, Inc.		500		13,655
Nihon Kohden Corp.		600		16,640
Nikon Corp.(a)		9,100		111,290
Nintendo Co. Ltd.		1,200		479,952
Nippon Electric Glass Co. Ltd.		10,500		233,099
Nippon Shokubai Co. Ltd.		900		55,772
Nippon Television Holdings, Inc.		1,700		22,680
Nissan Chemical Corp.		4,400		184,262
Nissan Motor Co. Ltd.		121,200		702,322
Nitori Holdings Co. Ltd.		1,100		173,636
Nitto Denko Corp.		5,100		286,762
NOK Corp.		1,200		17,899
NTN Corp.(a)		35,500		111,012
NTT Data Corp.		12,600		168,512
Oji Holdings Corp.		36,200		195,769
Ono Pharmaceutical Co. Ltd.		4,100		93,604
Otsuka Corp.		300		11,980
Otsuka Holdings Co. Ltd.(a)		11,500		512,604
Park24 Co. Ltd.		400		9,794
PeptiDream, Inc.(c)		1,000		51,103
Persol Holdings Co. Ltd.		1,800		33,734
Pola Orbis Holdings, Inc.(a)		18,100		431,125
Recruit Holdings Co. Ltd.		33,100		1,239,771
Rengo Co. Ltd.		1,400		10,666

Security	Shares		Value
Japan (continued)
Resona Holdings, Inc.		115,200	$	502,102
Sanwa Holdings Corp.		4,100		45,944
SCSK Corp.		700		36,298
Secom Co. Ltd.		5,000		446,213
Seino Holdings Co Ltd.		700		9,457
Seria Co. Ltd.		400		10,897
Seven & i Holdings Co. Ltd.		21,900		802,753
Shimadzu Corp.		4,000		125,093
Shimizu Corp.		9,900		100,850
Shin-Etsu Chemical Co. Ltd.		100		10,997
Shionogi & Co. Ltd.		8,000		494,892
SMC Corp.		400		182,926
Sojitz Corp.		8,000		25,785
Sompo Holdings, Inc.		900		35,343
Subaru Corp.		7,100		175,866
Sumitomo Chemical Co. Ltd.(a)		52,100		236,563
Sumitomo Heavy Industries Ltd.		3,900		110,779
Sumitomo Mitsui Financial Group, Inc.		29,400		1,085,899
Sumitomo Mitsui Trust Holdings, Inc.		6,200		245,092
Sumitomo Realty & Development Co. Ltd.		300		10,467
Sumitomo Rubber Industries Ltd.		8,600		104,866
Sundrug Co. Ltd.		5,900		213,473
Suntory Beverage & Food Ltd.		6,800		283,891
T&D Holdings, Inc.		43,900		555,147
Taisei Corp.		6,900		285,805
Taisho Pharmaceutical Holdings Co. Ltd.		200		14,759
Takeda Pharmaceutical Co. Ltd.		43,800		1,732,386
TIS, Inc.		400		23,645
Tokio Marine Holdings, Inc.		9,000		503,899
Tokyo Electron Ltd.		4,500		982,485
Topcon Corp.		600		7,755
Toshiba Corp.		3,200		108,614
Toyota Motor Corp.		13,100		923,045
Trend Micro, Inc.		7,000		358,189
TS Tech Co. Ltd.		5,300		164,507
TV Asahi Holdings Corp.		600		11,079
Ube Industries Ltd.(a)		23,100		500,305
Ulvac, Inc.		500		19,732
Yakult Honsha Co. Ltd.		600		33,068
Yamaguchi Financial Group, Inc.		4,800		32,462
Yamaha Motor Co. Ltd.		10,800		216,356
Yamato Holdings Co. Ltd.		17,800		303,483
Yamato Kogyo Co. Ltd.		400		10,016
Yokogawa Electric Corp.		3,900		68,488
Z Holdings Corp.		93,200		393,501
Zenkoku Hosho Co. Ltd.		2,900		123,141
Zeon Corp.		11,900		148,090
				39,513,631
Luxembourg — 0.1%
APERAM SA		2,337		75,071
RTL Group SA		1,696		83,565
				158,636
Macau — 0.2%
Sands China Ltd.		51,600		275,702
Netherlands — 5.6%
ABN AMRO Group NV CVA(d)		51,585		940,205
Aegon NV		280,480		1,283,926
Akzo Nobel NV		5,073		518,075
ASM International NV		3,185		359,499
ASML Holding NV		1,403		415,367
ASR Nederland NV		18,785		703,977
Euronext NV(d)		1,703		139,203
ING Groep NV		99,534		1,196,638

4 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 International Tilts Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
Netherlands (continued)
NN Group NV		39,342	$	1,495,892
Royal Dutch Shell PLC, B Shares		38,859		1,153,477
Royal Dutch Shell PLC, Class A		53,808		1,593,482
Wolters Kluwer NV		678		49,504
				9,849,245
New Zealand — 0.1%
Contact Energy Ltd.		1,970		9,463
Vector Ltd.		5,687		14,286
Xero Ltd.(c)		1,303		73,205
				96,954
Norway — 0.1%
Aker Solutions ASA(c)		13		37
DNB ASA		10,926		204,457
Dolphin Drilling ASA(c)(e)		8		1
				204,495
Singapore — 0.4%
CapitaLand Mall Trust		7,600		13,912
DBS Group Holdings Ltd.		19,100		368,272
Singapore Technologies Engineering Ltd.		44,200		129,446
Suntec Real Estate Investment Trust		147,200		201,508
				713,138
South Africa — 0.1%
Anglo American PLC		5,216		149,845
Spain — 1.8%
Acerinox SA		11,486		129,788
ACS Actividades de Construccion y Servicios SA		12,784		512,819
Amadeus IT Group SA		6,385		522,911
Banco Bilbao Vizcaya Argentaria SA		46,693		262,150
CaixaBank SA		60,608		190,858
CIE Automotive SA		426		10,110
Grifols SA		3,259		115,145
Mediaset Espana Comunicacion SA		9		57
Telefonica SA		197,089		1,378,263
				3,122,101
Sweden — 2.5%
Assa Abloy AB, Class B		42,012		982,049
Investor AB, Class B		16,641		908,495
Kinnevik AB		24,711		605,544
SSAB AB, A Shares		25,106		88,216
Telia Co. AB		2		9
Volvo AB, Class B		104,755		1,753,723
				4,338,036
Switzerland — 10.3%
Banque Cantonale Vaudoise, Registered Shares		69		56,324
Bucher Industries AG, Registered Shares		426		149,508
Cie Financiere Richemont SA, Registered Shares		5,635		440,380
Clariant AG, Registered Shares(c)		1,140		25,477
Dufry AG, Registered Shares(c)		1,408		139,619
Flughafen Zuerich AG, Registered Shares		1,079		196,950
Galenica AG(c)(d)		1,572		97,089
Geberit AG, Registered Shares		526		295,234
Givaudan SA, Registered Shares		193		604,668
LafargeHolcim Ltd., Registered Shares(c)		31,401		1,742,048
Logitech International SA, Registered Shares		21,987		1,041,585
Nestle SA, Registered Shares		24,586		2,661,808
Novartis AG, Registered Shares		34,823		3,297,375
Pargesa Holding SA, Bearer Shares		1,568		130,271
PSP Swiss Property AG, Registered Shares		649		89,610
Roche Holding AG		12,508		4,065,133
Schindler Holding AG, Participation Certificates		358		91,040
Sika AG, Registered Shares		1,999		375,403

Security	Shares		Value
Switzerland (continued)
Straumann Holding AG, Registered Shares		707	$	693,519
Sunrise Communications Group AG(c)(d)		8,213		645,235
UBS Group AG, Registered Shares(c)		50,260		634,250
Zurich Insurance Group AG		1,825		748,614
				18,221,140
United Kingdom — 15.2%
Ashtead Group PLC		15,252		487,678
Associated British Foods PLC		1		34
AstraZeneca PLC		12,613		1,262,460
Auto Trader Group PLC(d)		74,921		591,662
Aviva PLC		8,203		45,531
Bellway PLC		2,299		116,036
boohoo Group PLC(c)		11,269		44,467
BP PLC		172,543		1,085,434
British American Tobacco PLC		47,293		2,010,050
British Land Co. PLC		31,182		263,848
Britvic PLC		1,502		18,001
Centrica PLC		239,078		282,798
Cineworld Group PLC(a)		12,915		37,448
CK Hutchison Holdings Ltd.		81,000		772,374
Compass Group PLC		56,429		1,414,211
DCC PLC		1,719		149,104
Dechra Pharmaceuticals PLC		2,288		87,974
Diageo PLC		51,045		2,150,866
Direct Line Insurance Group PLC		46,147		190,935
Electrocomponents PLC		3,010		27,072
Experian PLC		50,774		1,721,211
GlaxoSmithKline PLC		110,795		2,603,353
Great Portland Estates PLC		2,381		27,176
Greggs PLC		5,847		178,347
Halma PLC		3,383		94,733
Hargreaves Lansdown PLC		835		21,419
HomeServe PLC		14,146		236,846
Howden Joinery Group PLC		8,898		79,274
HSBC Holdings PLC		295,736		2,315,150
IG Group Holdings PLC		27,122		249,684
Imperial Brands PLC		3,590		88,818
Intertek Group PLC		5,533		428,742
ITV PLC		41,996		84,025
J. Sainsbury PLC		120,997		368,950
JD Sports Fashion PLC		25,596		284,310
John Wood Group PLC		5,538		29,372
Lloyds Banking Group PLC		648,664		537,367
London Stock Exchange Group PLC		430		44,192
Man Group PLC		34,488		72,230
Moneysupermarket.com Group PLC		38,392		168,534
National Grid PLC		55,987		699,679
Pearson PLC		9,814		82,910
Pennon Group PLC		3,893		52,803
Prudential PLC		1,331		25,503
Reckitt Benckiser Group PLC		1,915		155,552
RELX PLC		14,383		363,075
Rentokil Initial PLC		29,844		178,872
Rightmove PLC		21,699		182,079
Rotork PLC		3,418		15,194
Royal Mail PLC		38,677		116,320
Severn Trent PLC		8,921		297,191
SSP Group PLC		26,738		230,198
Subsea 7 SA		5,937		71,025
Taylor Wimpey PLC		5,871		15,054
Unilever NV		17,300		992,859
Unilever PLC		10,726		613,984
Vodafone Group PLC		598,171		1,161,273
WH Smith PLC		2,492		85,884

SCHEDULES OF INVESTMENTS 5

Schedule of Investments  (continued) December 31, 2019 International Tilts Master Portfolio (Percentages shown are based on Net Assets)

Security	Shares		Value
United Kingdom (continued)
WM Morrison Supermarkets PLC		255,908	$	677,273
WPP PLC		3,283		46,199
				26,734,643
United States — 0.3%
James Hardie Industries PLC		23,044		450,382
Total Common Stocks — 96.5% (Cost — $153,426,002)				169,960,431
Preferred Stocks — 0.5%
Germany — 0.5%
Bayerische Motoren Werke AG, Preference Shares, 0.00%		254		15,637
Henkel AG & Co. KGaA, Preference Shares, 0.00%		3,501		361,655
Sartorius AG, Preference Shares, 0.00%		1,938		414,270
Total Preferred Stocks — 0.5% (Cost — $748,191)				791,562
Total Long-Term Investments — 97.0% (Cost — $154,174,193)				170,751,993

Security	Shares		Value
Short-Term Securities — 2.7%
BlackRock Cash Funds: Institutional, SL Agency Shares, 1.84%(f)(g)(h)		3,502,221	$	3,503,622
BlackRock Cash Funds: Treasury, SL Agency Shares, 1.52%(f)(h)		1,224,018		1,224,018
Total Short-Term Securities — 2.7% (Cost — $4,727,142)				4,727,640
Total Investments — 99.7% (Cost — $158,901,335)				175,479,633
Other Assets Less Liabilities — 0.3%				586,244
Net Assets — 100.0%			$	176,065,877

^(a)  Security, or a portion of the security, is on loan.

^(b)  A security contractually bound to one or more other securities to form a single saleable unit which cannot be sold separately.

^(c)  Non-income producing security.

^(d)  Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933, as amended. These securities may be resold in transactions exempt from registration to qualified institutional investors.

^(e)  Security is valued using significant unobservable inputs and is classified as Level 3 in the fair value hierarchy.

^(f)  Annualized7-day yield as of period end.

^(g)  All or a portion of the security was purchased with the cash collateral from loaned securities.

^(h)  During the year ended December 31, 2019, investments in issuers considered to be an affiliate/affiliates of the Master Portfolio for purposes of Section 2(a)(3) of the Investment Company Act of 1940, as amended, were as follows:

Affiliate	Shares Held at 12/31/18	Net Activity		Shares Held at 12/31/19		Value at 12/31/19		Income			Net Realized Gain (Loss)	(a)		Change in Unrealized Appreciation (Depreciation)
BlackRock Cash Funds: Institutional, SL Agency Shares	6,307,282	(2,805,061	)	3,502,221	$	3,503,622	$	26,388	(b)	$	527		$	361
BlackRock Cash Funds: Treasury, SL Agency Shares	1,531,004	(306,986	)	1,224,018		1,224,018		34,778			—			—
					$	4,727,640	$	61,166		$	527		$	361

^(a)  Includes net capital gain distributions, if applicable.

^(b)  All or a portion represents securities lending income earned from the reinvestment of cash collateral from loaned securities, net of fees and collateral investment expenses, and other payments to and from borrowers of securities.

Derivative Financial Instruments Outstanding as of Period End

Futures Contracts

Description	Number of Contracts		Expiration Date		Notional Amount (000)		Value/ Unrealized Appreciation (Depreciation)
Long Contracts
Yen Denom Nikkei Index		11		03/12/20	$	1,186	$	(1,280	)
SPI 200 Index		3		03/19/20		348		(8,514	)
Euro Stoxx 50 Index		61		03/20/20		2,552		(5,340	)
FTSE 100 Index		10		03/20/20		993		4,944
							$	(10,190	)

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) December 31, 2019 International Tilts Master Portfolio

Derivative Financial Instruments Categorized by Risk Exposure

As of period end, the fair values of derivative financial instruments located in the Statement of Assets and Liabilities were as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Assets — Derivative Financial Instrument
Futures contracts
Unrealized appreciation on futures contracts(a)	$	—	$	—	$	4,944	$	—	$	—	$	—	$	4,944
Liabilities — Derivative Financial Instrument
Futures contracts
Unrealized depreciation on futures contracts(a)	$	—	$	—	$	15,134	$	—	$	—	$	—	$	15,134

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts, if any, are reported in the Schedule of Investments. In the Statement of Assets and Liabilities, only current day’s variation margin is reported in receivables or payables and the net cumulative unrealized appreciation (depreciation) is included in accumulated earnings (loss).

For the period ended December 31, 2019, the effect of derivative financial instruments in the Statement of Operations was as follows:

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Net Realized Gain (Loss) from:
Future contracts	$	—	$	—	$	1,112,191	$	—	$	—	$	—	$	1,112,191

	Commodity Contracts		Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Net Change in Unrealized Appreciation (Depreciation) on:
Future contracts	$	—	$	—	$	47,911	$	—	$	—	$	—	$	47,911

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	7,874,358
Average notional value of contracts — short		—	(a)

^(a)  Derivative not held atquarter-end. The risk exposure table serves as an indicator of activity during the period.

For more information about the Master Portfolio’s investment risks regarding derivative financial instruments, refer to the Notes to Financial Statements.

Fair Value Hierarchy as of Period End

Various inputs are used in determining the fair value of investments and derivative financial instruments. For information about the Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Financial Statements.

The following tables summarize the Master Portfolio’s investments and derivative financial instruments categorized in the disclosure hierarchy:

	Level 1		Level 2		Level 3		Total
Assets:
Investments:
Common Stocks:
Australia	$	—	$	13,477,571	$	—	$	13,477,571
Austria		141,212		98,700		—		239,912
Belgium		—		1,643,464		—		1,643,464
China		—		779,335		—		779,335
Denmark		2,047,584		2,149,086		—		4,196,670
Finland		107,510		3,937,566		—		4,045,076
France		384,520		20,343,931		—		20,728,451
Germany		1,518,096		14,565,982		—		16,084,078
Hong Kong		—		3,079,205		—		3,079,205
Ireland		115,984		147,385		—		263,369

SCHEDULES OF INVESTMENTS 7

Schedule of Investments  (continued) December 31, 2019 International Tilts Master Portfolio

Fair Value Hierarchy as of Period End (continued)

	Level 1			Level 2		Level 3		Total
Israel	$	—		$	235,392	$	—	$	235,392
Italy		—			1,359,960		—		1,359,960
Japan		—			39,513,631		—		39,513,631
Luxembourg		—			158,636		—		158,636
Macau		—			275,702		—		275,702
Netherlands		—			9,849,245		—		9,849,245
New Zealand		—			96,954		—		96,954
Norway		—			204,494		1		204,495
Singapore		—			713,138		—		713,138
South Africa		—			149,845		—		149,845
Spain		—			3,122,101		—		3,122,101
Sweden		—			4,338,036		—		4,338,036
Switzerland		56,324			18,164,816		—		18,221,140
United Kingdom		2,052,107			24,682,536		—		26,734,643
United States		—			450,382		—		450,382
Preferred Stocks		—			791,562		—		791,562
Short-Term Securities		4,727,640			—		—		4,727,640
	$	11,150,977		$	164,328,655	$	1	$	175,479,633
Derivative Financial Instruments(a)
Assets:
Other contracts	$	4,944		$	—	$	—	$	4,944
Liabilities:
Equity contracts		(15,134	)		—		—		(15,134	)
	$	(10,190	)	$	—	$	—	$	(10,190	)

^(a)  Derivative financial instruments are futures contracts. Futures contracts are valued at the unrealized appreciation (depreciation) on the instrument.

See notes to financial statements.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

December 31, 2019

	International Tilts Master Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $3,314,009, cost — $154,174,193)	$	170,751,993
Investments at value — affiliated (cost — $4,727,142)		4,727,640
Cash pledged for futures contracts		312,910
Foreign currency at value (cost — $4,337,889)		4,396,276
Receivables:
Securities lending income — affiliated		963
Dividends — affiliated		1,616
Dividends — unaffiliated		215,190
Variation margin on futures contracts		724
Prepaid expenses		5,545
Total assets		180,412,857
LIABILITIES
Cash collateral on securities loaned at value		3,500,238
Payables:
Administration fees		14,552
Investment advisory fees		101,713
Other accrued expenses		22,290
Trustees’ fees		2,587
Variation margin on futures contracts		46,814
Withdrawals to investors		658,786
Total liabilities		4,346,980
NET ASSETS	$	176,065,877
NET ASSETS CONSIST OF
Investors’ capital	$	159,435,883
Net unrealized appreciation (depreciation)		16,629,994
NET ASSETS	$	176,065,877

See notes to financial statements.

FINANCIAL STATEMENTS 9

Statement of Operations

Year Ended December 31, 2019

	International Tilts Master Portfolio
INVESTMENT INCOME
Dividends — affiliated	$	34,778
Dividends — unaffiliated		5,985,697
Securities lending income — affiliated — net		26,388
Foreign taxes withheld		(242,768	)
Total investment income		5,804,095
EXPENSES
Investment advisory		642,081
Administration		80,260
Professional		22,689
Trustees		13,012
Total expenses		758,042
Less fees waived and/or reimbursed by the Manager		(117,129	)
Total expenses after fees waived and/or reimbursed		640,913
Net investment income		5,163,182
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain from:
Futures contracts		1,112,191
Foreign currency transactions		14,121
Investments — affiliated		527
Investments — unaffiliated		3,765,818
		4,892,657
Net change in unrealized appreciation (depreciation) on:
Futures contracts		47,911
Foreign currency translations		69,934
Investments — affiliated		361
Investments — unaffiliated		22,631,149
		22,749,355
Net realized and unrealized gain		27,642,012
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	32,805,194

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statements of Changes in Net Assets

	International Tilts Master Portfolio
	Year Ended December 31,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	5,163,182		$	4,508,257
Net realized gain (loss)		4,892,657			(914,470	)
Net change in unrealized appreciation (depreciation)		22,749,355			(30,450,447	)
Net increase (decrease) in net assets resulting from operations		32,805,194			(26,856,660	)
CAPITAL TRANSACTIONS
Proceeds from contributions		39,066,209			63,886,547
Value of withdrawals		(43,182,203	)		(53,622,664	)
Net increase (decrease) in net assets derived from capital transactions		(4,115,994	)		10,263,883
NET ASSETS
Total increase (decrease) in net assets		28,689,200			(16,592,777	)
Beginning of year		147,376,677			163,969,454
End of year	$	176,065,877		$	147,376,677

See notes to financial statements.

FINANCIAL STATEMENTS 11

Financial Highlights  

(For a share outstanding throughout each period)

	International Tilts Master Portfolio
	Year Ended December 31,
	2019			2018			2017			2016			2015
Total Return
Total return		22.30	%		(15.06	)%		29.06	%		0.00	%		2.25	%
Ratios to Average Net Assets
Total expenses		0.47	%		0.46	%		0.47	%		0.46	%		0.45	%
Total expenses after fees waived and/or reimbursed		0.40	%		0.40	%		0.40	%		0.40	%		0.43	%
Net investment income		3.22	%		2.68	%(a)		2.81	%		2.91	%		2.65	%
Supplemental Data
Net assets, end of year (000)	$	176,066		$	147,377		$	163,969		$	187,213		$	304,851
Portfolio turnover rate		151	%		130	%		106	%		98	%		107	%

^(a)  The ratio of net investment income to average net assets includes 0.04% resulting from a special dividend.

See notes to financial statements.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  

1. ORGANIZATION

Master Investment Portfolio (“MIP”) is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as anopen-end management investment company. MIP is organized as a Delaware statutory trust. International Tilts Master Portfolio (the “Master Portfolio”) is a series of MIP. The Master Portfolio is classified as diversified.

The Master Portfolio, together with certain other registered investment companies advised by BlackRock Advisors, LLC (the “Manager”) or its affiliates, is included in a complex of equity, multi-asset, index and money market funds referred to as the BlackRock Multi-Asset Complex.

2. SIGNIFICANT ACCOUNTING POLICIES

The financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which may require management to make estimates and assumptions that affect the reported amounts of assets and liabilities in the financial statements, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. The Master Portfolio is considered an investment company under U.S. GAAP and follows the accounting and reporting guidance applicable to investment companies. Below is a summary of significant accounting policies:

Investment Transactions and Income Recognition:For financial reporting purposes, investment transactions are recorded on the dates the transactions are executed. Realized gains and losses on investment transactions are determined on the identified cost basis. Dividend income is recorded on theex-dividend date. Dividends from foreign securities where theex-dividend date may have passed are subsequently recorded when the Master Portfolio is informed of theex-dividend date. Under the applicable foreign tax laws, a withholding tax at various rates may be imposed on capital gains, dividends and interest. Upon notification from issuers, a portion of the dividend income received from a real estate investment trust may be redesignated as a reduction of cost of the related investment and/or realized gain.

Foreign Currency Translation:The Master Portfolio’s books and records are maintained in U.S. dollars. Securities and other assets and liabilities denominated in foreign currencies are translated into U.S. dollars using exchange rates determined as of the close of trading on the New York Stock Exchange (“NYSE”). Purchases and sales of investments are recorded at the rates of exchange prevailing on the respective dates of such transactions. Generally, when the U.S. dollar rises in value against a foreign currency, the investments denominated in that currency will lose value; the opposite effect occurs if the U.S. dollar falls in relative value.

The Master Portfolio does not isolate the portion of the results of operations arising as a result of changes in the exchange rates from the changes in the market prices of investments held or sold for financial reporting purposes. Accordingly, the effects of changes in exchange rates on investments are not segregated in the Statement of Operations from the effects of changes in market prices of those investments, but are included as a component of net realized and unrealized gain (loss) from investments. The Master Portfolio reports realized currency gains (losses) on foreign currency related transactions as components of net realized gain (loss) for financial reporting purposes, whereas such components are generally treated as ordinary income for U.S. federal income tax purposes.

Segregation and Collateralization:In cases where the Master Portfolio enters into certain investments (e.g., futures contracts) that would be treated as “senior securities” for 1940 Act purposes, the Master Portfolio may segregate or designate on itsbooks and records cash or liquid assets having a market value at least equal to the amount of its future obligations under such investments. Doing so allows the investment to be excluded from treatment as a “senior security.” Furthermore, if required by an exchange or counterparty agreement, the Master Portfolio may be required to deliver/deposit cash and/or securities to/with an exchange, or broker-dealer or custodian as collateral for certain investments or obligations.

Indemnifications:In the normal course of business, the Master Portfolio enters into contracts that contain a variety of representations that provide general indemnification. The Master Portfolio’s maximum exposure under these arrangements is unknown because it involves future potential claims against the Master Portfolio, which cannot be predicted with any certainty.

Other: Expenses directly related to the Master Portfolio are charged to the Master Portfolio. Other operating expenses shared by several funds, including other funds managed by the Manager, are prorated among those funds on the basis of relative net assets or other appropriate methods.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

Investment Valuation Policies: The Master Portfolio’s investments are valued at fair value (also referred to as “market value” within the financial statements) as of the close of trading on the NYSE (generally 4:00 p.m., Eastern time). U.S. GAAP defines fair value as the price the Master Portfolio would receive to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. The Master Portfolio determines the fair values of its financial instruments using various independent dealers or pricing services under policies approved by the Board of Trustees of MIP (the “Board”). The BlackRock Global Valuation Methodologies Committee (the “Global Valuation Committee”) is the committee formed by management to develop global pricing policies and procedures and to oversee the pricing function for all financial instruments.

Fair Value Inputs and Methodologies: The following methods and inputs are used to establish the fair value of the Master Portfolio’s assets and liabilities:

• Equity investments traded on a recognized securities exchange are valued at the official closing price each day, if available. For equity investments traded on more than one exchange, the official closing price on the exchange where the stock is primarily traded is used. Equity investments traded on a recognized exchange for which there were no sales on that day may be valued at the last available bid (long positions) or ask (short positions) price.

Generally, trading in foreign instruments is substantially completed each day at various times prior to the close of trading on the NYSE. Occasionally, events affecting the values of such instruments may occur between the foreign market close and the close of trading on the NYSE that may not be reflected in the computation of the Master Portfolio’s net assets. Each business day, the Master Portfolio uses a pricing service to assist with the valuation of certain foreign

NOTESTO FINANCIAL STATEMENTS 13

Notes to Financial Statements  (continued)

exchange-traded equity securities and foreign exchange-traded andover-the-counter (“OTC”) options (the “Systematic Fair Value Price”). Using current market factors, the Systematic Fair Value Price is designed to value such foreign securities and foreign options at fair value as of the close of trading on the NYSE, which follows the close of the local markets.

• Investments inopen-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• Futures contracts traded on exchanges are valued at their last sale price.

If events (e.g., a company announcement, market volatility or a natural disaster) occur that are expected to materially affect the value of such investments, or in the event that the application of these methods of valuation results in a price for an investment that is deemed not to be representative of the market value of such investment, or if a price is not available, the investment will be valued by the Global Valuation Committee, or its delegate, in accordance with a policy approved by the Board as reflecting fair value (“Fair Valued Investments”). The fair valuation approaches that may be used by the Global Valuation Committee will include market approach, income approach and cost approach. Valuation techniques such as discounted cash flow, use of market comparables and matrix pricing are types of valuation approaches and are typically used in determining fair value. When determining the price for Fair Valued Investments, the Global Valuation Committee, or its delegate, seeks to determine the price that the Master Portfolio might reasonably expect to receive or pay from the current sale or purchase of that asset or liability in anarm’s-length transaction. Fair value determinations shall be based upon all available factors that the Global Valuation Committee, or its delegate, deems relevant and consistent with the principles of fair value measurement. The pricing of all Fair Valued Investments is subsequently reported to the Board or a committee thereof on a quarterly basis.

For investments in equity or debt issued by privately held companies or funds (“Private Company” or collectively, the “Private Companies”) and other Fair Valued Investments, the fair valuation approaches that are used by the Global Valuation Committee and third party pricing services utilize one or a combination of, but not limited to, the following inputs.

	Standard Inputs Generally Considered By Third Party Pricing Services
Market approach	(i)  recent market transactions, including subsequent rounds of financing, in the underlying investment or comparable issuers; (ii) recapitalizations and other transactions across the capital structure; and (iii)   market multiples of comparable issuers.
Income approach	(i)  future cash flows discounted to present and adjusted as appropriate for liquidity, credit, and/or market risks; (ii) quoted prices for similar investments or assets in active markets; and (iii)   other risk factors, such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks, recovery rates, liquidation amounts and/or default rates.
Cost approach	(i)  audited or unaudited financial statements, investor communications and financial or operational metrics issued by the Private Company; (ii) changes in the valuation of relevant indices or publicly traded companies comparable to the Private Company; (iii)   relevant news and other public sources; and (iv)   known secondary market transactions in the Private Company’s interests and merger or acquisition activity in companies comparable to the Private Company.

Investments in series of preferred stock issued by Private Companies are typically valued utilizing market approach in determining the enterprise value of the company. Such investments often contain rights and preferences that differ from other series of preferred and common stock of the same issuer. Valuation techniques such as an option pricing model (“OPM”), a probability weighted expected return model (“PWERM”) or a hybrid of those techniques are used in allocating enterprise value of the company, as deemed appropriate under the circumstances. The use of OPM and PWERM techniques involve a determination of the exit scenarios of the investment in order to appropriately allocate the enterprise value of the company among the various parts of its capital structure.

The Private Companies are not subject to the public company disclosure, timing, and reporting standards as other investments held by the Fund. Typically, the most recently available information by a Private Company is as of a date that is earlier than the date the Fund is calculating its NAV. This factor may result in a difference between the value of the investment and the price the Fund could receive upon the sale of the investment.

Fair Value Hierarchy: Various inputs are used in determining the fair value of investments and derivative financial instruments. These inputs to valuation techniques are categorized into a fair value hierarchy consisting of three broad levels for financial statement purposes as follows:

• Level 1 — Unadjusted price quotations in active markets/exchanges for identical assets or liabilities that the Master Portfolio has the ability to access

• Level 2 — Other observable inputs (including, but not limited to, quoted prices for similar assets or liabilities in markets that are active, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the assets or liabilities (such as interest rates, yield curves, volatilities, prepayment speeds, loss severities, credit risks and default rates) or other market–corroborated inputs)

• Level 3 — Unobservable inputs based on the best information available in the circumstances, to the extent observable inputs are not available (including the Global Valuation Committee’s assumptions used in determining the fair value of investments and derivative financial instruments)

The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Accordingly, the degree of judgment exercised in determining fair value is greatest for instruments categorized in Level 3. The inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, for disclosure purposes, the fair value hierarchy classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Investments classified within Level 3 have significant unobservable inputs used by the Global Valuation Committee in determining the price for Fair Valued Investments. Level 3 investments include equity or debt issued by Private Companies. There may not be a secondary market, and/or there are a limited number of investors. The categorization of a value determined for investments and derivative financial instruments is based on the pricing transparency of the investments and derivative financial instruments and is not necessarily an indication of the risks associated with investing in those securities.

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

4. SECURITIES AND OTHER INVESTMENTS

Preferred Stocks: Preferred stock has a preference over common stock in liquidation (and generally in receiving dividends as well), but is subordinated to the liabilities of the issuer in all respects. As a general rule, the market value of preferred stock with a fixed dividend rate and no conversion element varies inversely with interest rates and perceived credit risk, while the market price of convertible preferred stock generally also reflects some element of conversion value. Because preferred stock is junior to debt securities and other obligations of the issuer, deterioration in the credit quality of the issuer will cause greater changes in the value of a preferred stock than in a more senior debt security with similar stated yield characteristics. Unlike interest payments on debt securities, preferred stock dividends are payable only if declared by the issuer’s board of directors. Preferred stock also may be subject to optional or mandatory redemption provisions.

Securities Lending:The Master Portfolio may lend its securities to approved borrowers, such as brokers, dealers and other financial institutions. The borrower pledges and maintains with the Master Portfolio collateral consisting of cash, an irrevocable letter of credit issued by a bank, or securities issued or guaranteed by the U.S. Government. The initial collateral received by the Master Portfolio is required to have a value of at least 102% of the current value of the loaned securities for securities traded on U.S. exchanges and a value of at least 105% for all other securities. The collateral is maintained thereafter at a value equal to at least 100% of the current market value of the securities on loan. The market value of the loaned securities is determined at the close of each business day of the Master Portfolio and any additional required collateral is delivered to the Master Portfolio, or excess collateral returned by the Master Portfolio, on the next business day. During the term of the loan, the Master Portfolio is entitled to all distributions made on or in respect of the loaned securities, but does not receive interest income on securities received as collateral. Loans of securities are terminable at any time and the borrower, after notice, is required to return borrowed securities within the standard time period for settlement of securities transactions.

The market value of any securities on loan, all of which were classified as common stocks in the Master Portfolio’s Schedule of Investments, and the value of any related collateral are shown separately in the Statement of Assets and Liabilities as a component of investments at value-unaffiliated, and collateral on securities loaned at value, respectively. As of period end, any securities on loan were collateralized by cash and/or U.S. Government obligations. Cash collateral invested by the securities lending agent, BlackRock Institutional Trust Company, N.A. (“BTC”), if any, is disclosed in the Schedule of Investments.

Securities lending transactions are entered into by the Master Portfolio under Master Securities Lending Agreements (each, an “MSLA”), which provide the right, in the event of default (including bankruptcy or insolvency), for thenon-defaulting party to liquidate the collateral and calculate a net exposure to the defaulting party or request additional collateral. In the event that a borrower defaults, the Master Portfolio, as lender, would offset the market value of the collateral received against the market value of the securities loaned. When the value of the collateral is greater than that of the market value of the securities loaned, the lender is left with a net amount payable to the defaulting party. However, bankruptcy or insolvency laws of a particular jurisdiction may impose restrictions on or prohibitions against such a right of offset in the event of an MSLA counterparty’s bankruptcy or insolvency. Under the MSLA, absent an event of default, the borrower can resell orre-pledge the loaned securities, and the Master Portfolio can reinvest cash collateral received in connection with loaned securities. Upon an event of default, the parties’ obligations to return the securities or collateral to the other party are extinguished, and the parties can resell orre-pledge the loaned securities or the collateral received in connection with the loaned securities in order to satisfy the defaulting party’s net payment obligation for all transactions under the MSLA. The defaulting party remains liable for any deficiency.

As of period end, the following table is a summary of the Master Portfolio’s securities lending agreements by counterparty which are subject to offset under an MSLA:

Counterparty	Securities Loaned at Value		Cash Collateral Received (a)			Net Amount
Goldman Sachs & Co.	$	145,294	$	(145,294	)	$	—
Jefferies LLC		237,630		(237,630	)		—
J.P. Morgan Securities LLC		100,283		(100,283	)		—
Morgan Stanley & Co. LLC		1,564,694		(1,564,694	)		—
State Street Bank and Trust Co.		815,216		(815,216	)		—
UBS AG		450,892		(450,892	)		—
	$	3,314,009	$	(3,314,009	)	$	—

^(a)  Collateral received in excess of the market value of securities on loan is not presented in this table. The total cash collateral received by the Fund is disclosed in the Fund’s Statement of Assets and Liabilities.

The risks of securities lending include the risk that the borrower may not provide additional collateral when required or may not return the securities when due. To mitigate these risks, the Master Portfolio benefits from a borrower default indemnity provided by BlackRock, Inc. (“BlackRock”).BlackRock’s indemnity allows for full replacement of the securities loaned to the extent the collateral received does not cover the value on the securities loaned in the event of borrower default. The Master Portfolio could incur a loss if the value of an investment purchased with cash collateral falls below the market value of loaned securities or if the value of an investment purchased with cash collateral falls below the value of the original cash collateral received. Such losses are borne entirely by the Master Portfolio.

5. DERIVATIVE FINANCIAL INSTRUMENTS

The Master Portfolio engages in various portfolio investment strategies using derivative contracts both to increase the returns of the Master Portfolio and/or to manage its exposure to certain risks such as credit risk, equity risk, interest rate risk, foreign currency exchange rate risk, commodity price risk or other risks (e.g., inflation risk). Derivative financial instruments categorized by risk exposure are included in the Schedule of Investments. These contracts may be transacted on an exchange or OTC.

Futures Contracts: Futures contracts are purchased or sold to gain exposure to, or manage exposure to, changes in interest rates (interest rate risk) and changes in the value of equity securities (equity risk) or foreign currencies (foreign currency exchange rate risk).

NOTESTO FINANCIAL STATEMENTS 15

Notes to Financial Statements  (continued)

Futures contracts are agreements between the Master Portfolio and a counterparty to buy or sell a specific quantity of an underlying instrument at a specified price and on a specified date. Depending on the terms of a contract, it is settled either through physical delivery of the underlying instrument on the settlement date or by payment of a cash amount on the settlement date. Upon entering into a futures contract, the Master Portfolio is required to deposit initial margin with the broker in the form of cash or securities in an amount that varies depending on a contract’s size and risk profile. The initial margin deposit must then be maintained at an established level over the life of the contract. Amounts pledged, which are considered restricted, are included in cash pledged for futures contracts in the Statement of Assets and Liabilities.

Securities deposited as initial margin are designated in the Schedule of Investments and cash deposited, if any, are shown as cash pledged for futures contracts in the Statement of Assets and Liabilities. Pursuant to the contract, the Master Portfolio agrees to receive from or pay to the broker an amount of cash equal to the daily fluctuation in market value of the contract (“variation margin”). Variation margin is recorded as unrealized appreciation (depreciation) and, if any, shown as variation margin receivable (or payable) on futures contracts in the Statement of Assets and Liabilities. When the contract is closed, a realized gain or loss is recorded in the Statement of Operations equal to the difference between the notional amount of the contract at the time it was opened and the notional amount at the time it was closed. The use of futures contracts involves the risk of an imperfect correlation in the movements in the price of futures contracts and interest, foreign currency exchange rates or underlying assets.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory: MIP, on behalf of the Master Portfolio, entered into an Investment Advisory Agreement with the Manager, the Master Portfolio’s investment adviser and an indirect, wholly-owned subsidiary of BlackRock, to provide investment advisory services. The Manager is responsible for the management of the Master Portfolio’s portfolio and provides the personnel, facilities, equipment and certain other services necessary to the operations of the Master Portfolio.

For such services, the Master Portfolio pays the Manager a monthly fee at an annual rate equal to the following percentages of the average daily value of the Master Portfolio’s net assets.

Average Daily Net Assets	Investment Advisory Fee
First $1 Billion		0.40	%
$1 Billion — $3 Billion		0.38
$3 Billion — $5 Billion		0.36
$5 Billion — $10 Billion		0.35
Greater than $10 Billion		0.34

The Manager entered into separatesub-advisory agreements with BlackRock Fund Advisors (“BFA”) and BlackRock International Limited (“BIL”), each an affiliate of the Manager. The Manager pays each of BFA and BIL for services it provides for that portion of the Master Portfolio for which it acts assub-adviser, a monthly fee that is equal to a percentage of the investment advisory fees paid by the Master Portfolio to the Manager.

Administration: MIP, on behalf of the Master Portfolio, entered into an Administration Agreement with the Manager, which has agreed to provide general administrative services (other than investment advice and related portfolio activities). The Manager has agreed to bear all of the Master Portfolio’s ordinary operating expenses, excluding, generally, investment advisory fees, distribution fees, brokerage and other expenses related to the execution of portfolio transactions, extraordinary expenses and certain other expenses which are borne by the Master Portfolio. The Manager is entitled to receive for these administrative services an annual fee of 0.05% based on the average daily net assets of the Master Portfolio.

From time to time, the Manager may waive such fees in whole or in part. Any such waiver will reduce the expenses of the Master Portfolio and, accordingly, have a favorable impact on its performance. The Manager may delegate certain of its administration duties tosub-administrators. For the year ended December 31, 2019, the Manager waived $80,260.

Expense Waivers and Reimbursements: The fees and expenses of MIP’s trustees who are not “interested persons” of MIP, as defined in the 1940 Act (“Independent Trustees”), counsel to the Independent Trustees and the Master Portfolio’s independent registered public accounting firm (together, the “independent expenses”) are paid directly by the Master Portfolio. The Manager has contractually agreed to reimburse the Master Portfolio or provide an offsetting credit against the administration fees paid by the Master Portfolio in an amount equal to the independent expenses through April 30, 2020. For the year ended December 31, 2019, the amount waived was $35,701.

The Manager voluntarily agreed to waive its investment advisory fees by the amount of investment advisory fees the Master Portfolio pays to the Manager indirectly through its investment in affiliated money market funds (the “affiliated money market fund waiver”). This amount is included in fees waived and/or reimbursed by the Manager in the Statement of Operations. For the year ended December 31, 2019, the amounts waived were $1,168.

The Manager has contractually agreed to waive its investment advisory fee with respect to any portion of the Master Portfolio’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through April 30, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees or by a vote of a majority of the outstanding voting securities of the Master Portfolio. For the year ended December 31, 2019, there were no fees waived and/or reimbursed by the Manager pursuant to this arrangement.

The Manager is entitled to receive an annual administrative fee of 0.05% of the Master Portfolio’s average daily net assets for providing administration services. The Manager has contractually agreed to waive this administration fee through April 30, 2020. This waiver agreement may be terminated upon 90 days’ notice by a majority of the Independent Trustees or by a majority of the outstanding voting securities of the Master Portfolio.

Securities Lending:The U.S. Securities and Exchange Commission (“SEC”) has issued an exemptive order which permits BTC, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BTC bears all operational costs directly related to securities

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

lending. The Master Portfolio is responsible for fees in connection with the investment of cash collateral received for securities on loan (the “collateral investment fees”). The cash collateral is invested in a money market fund managed by the Manager or its affiliates. However, BTC has agreed to reduce the amount of securities lending income it receives in order to effectively limit the collateral investment fees the Master Portfolio bears to an annual rate of 0.04%. The shares of such money market fund will not be subject to a sales load, distribution fee or service fee. The money market fund in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value redeemed or temporarily restrict redemptions for up to 10 business days during a 90 day period, in the event that the money market fund’s weekly liquid assets fall below certain thresholds.

Securities lending income is equal to the total of income earned from the reinvestment of cash collateral, net of fees and other payments to and from borrowers of securities, and less the collateral investment fees. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BTC as compensation for its services as securities lending agent.

Pursuant to the current securities lending agreement, the Master Portfolio retains 82% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Multi-Asset Complex in a calendar year exceeds a specified threshold, the Master Portfolio, pursuant to the securities lending agreement, will retain for the remainder of that calendar year securities lending income in an amount equal to 85% of securities lending income (which excludes collateral investment fees), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment fees.

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Statement of Operations. For the year ended December 31, 2019, the Master Portfolio paid BTC $5,641 for securities lending agent services.

Interfund Lending: In accordance with an exemptive order (the “Order”) from the SEC, the Master Portfolio may participate in a joint lending and borrowing facility for temporary purposes (the “Interfund Lending Program”), subject to compliance with the terms and conditions of the Order, and to the extent permitted by the Master Portfolio’s investment policies and restrictions. The Master Portfolio is currently permitted to borrow and lend under the Interfund Lending Program.

A lending BlackRock fund may lend in aggregate up to 15% of its net assets, but may not lend more than 5% of its net assets to any one borrowing fund through the Interfund Lending Program. A borrowing BlackRock fund may not borrow through the Interfund Lending Program or from any other source more than 33 1/3% of its total assets (or any lower threshold provided for by the fund’s investment restrictions). If a borrowing BlackRock fund’s total outstanding borrowings exceed 10% of its total assets, each of its outstanding interfund loans will be subject to collateralization of at least 102% of the outstanding principal value of the loan. All interfund loans are for temporary or emergency purposes and the interest rate to be charged will be the average of the highest current overnight repurchase agreement rate available to a lending fund and the bank loan rate, as calculated according to a formula established by the Board.

During the year ended December 31, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Trustees and Officers:Certain trustees and/or officers of MIP are directors and/or officers of BlackRock or its affiliates.

Other Transactions: The Master Portfolio may purchase securities from, or sell securities to, an affiliated fund provided the affiliation is due solely to having a common investment adviser, common officers, or common trustees. For the year ended December 31, 2019, the purchase and sale transactions and any net realized gains (losses) with an affiliated funds in compliance with Rule17a-7 under the 1940 Act were as follows:

Purchases	Sales		Net Realized Gain (Loss)
$353,985	$	208,804	$(6,351)

7. PURCHASES AND SALES

For the year ended December 31, 2019, purchases and sales of investments excluding short-term securities, were $233,493,909 and $235,264,036, respectively.

8. INCOME TAX INFORMATION

The Master Portfolio is classified as a partnership for U.S. federal income tax purposes. As such, each investor in the Master Portfolio is treated as the owner of its proportionate share of net assets, income, expenses and realized and unrealized gains and losses of the Master Portfolio. Therefore, no U.S. federal income tax provision is required. It is intended that the Master Portfolio’s assets will be managed so an investor in the Master Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code of 1986, as amended.

The Master Portfolio files U.S. federal and various state and local tax returns. No income tax returns are currently under examination. The statute of limitations on the Master Portfolio’s U.S. federal tax returns generally remains open for each of the four years ended December 31, 2019. The statutes of limitations on the Master Portfolio’s state and local tax returns may remain open for an additional year depending upon the jurisdiction.

Management has analyzed tax laws and regulations and their application to the Master Portfolio as of December 31, 2019, inclusive of the open tax return years, and does not believe that there are any uncertain tax positions that require recognition of a tax liability in the Master Portfolio’s financial statements.

NOTESTO FINANCIAL STATEMENTS 17

Notes to Financial Statements  (continued)

As of December 31, 2019, gross unrealized appreciation and depreciation for investments and derivatives based on cost for U.S. federal income tax purposes were as follows:

Tax cost	$	162,322,081
Gross unrealized appreciation	$	18,832,816
Gross unrealized depreciation		(5,683,778	)
Net unrealized appreciation	$	13,149,038

9. BANK BORROWINGS

MIP, on behalf of the Master Portfolio, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a364-day, $2.25 billion credit agreement with a group of lenders. Under this agreement, the Master Portfolio may borrow to fund shareholder redemptions. Excluding commitments designated for certain individual funds, the Participating Funds, including the Master Portfolio, can borrow up to an aggregate commitment amount of $1.75 billion at any time outstanding, subject to asset coverage and other limitations as specified in the agreement. The credit agreement has the following terms: a fee of 0.10% per annum on unused commitment amounts and interest at a rate equal to the higher of(a) one-month LIBOR (but, in any event, not less than 0.00%) on the date the loan is made plus 0.80% per annum or (b) the Fed Funds rate (but, in any event, not less than 0.00%) in effect from time to time plus 0.80% per annum on amounts borrowed. The agreement expires in April 2020 unless extended or renewed. Prior to April 18, 2019, Participating Funds paid an upfront commitment fee of 0.02% on the total commitment amounts, in addition to administration, legal and arrangement fees, which are included in miscellaneous expenses in the Statement of Operations. These fees were allocated among such funds based upon portions of the aggregate commitment available to them and relative net assets of Participating Funds. During the year ended December 31, 2019, the Master Portfolio did not borrow under the credit agreement.

10. PRINCIPAL RISKS

In the normal course of business, the Master Portfolio invests in securities or other instruments and may enter into certain transactions, and such activities subject the Master Portfolio to various risks, including among others, fluctuations in the market (market risk) or failure of an issuer to meet all of its obligations. The value of securities or other instruments may also be affected by various factors, including, without limitation: (i) the general economy; (ii) the overall market as well as local, regional or global political and/or social instability; (iii) regulation, taxation or international tax treaties between various countries; or (iv) currency, interest rate and price fluctuations. The Master Portfolio’s prospectus provides details of the risks to which the Master Portfolio is subject.

The Master Portfolio may be exposed to additional risks when reinvesting cash collateral in money market funds that do not seek to maintain a stable NAV per share of $1.00, which may be subject to redemption gates or liquidity fees under certain circumstances.

Valuation Risk: The market values of equities, such as common stocks and preferred securities or equity related investments, such as futures and options, may decline due to general market conditions which are not specifically related to a particular company. They may also decline due to factors which affect a particular industry or industries. The Master Portfolio may invest in illiquid investments. An illiquid investment is any investment that the Master Portfolio reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. The Master Portfolio may experience difficulty in selling illiquid investments in a timely manner at the price that it believes the investments are worth. Prices may fluctuate widely over short or extended periods in response to company, market or economic news. Markets also tend to move in cycles, with periods of rising and falling prices. This volatility may cause the Master Portfolio’s NAV to experience significant increases or decreases over short periods of time. If there is a general decline in the securities and other markets, the NAV of the Master Portfolio may lose value, regardless of the individual results of the securities and other instruments in which the Master Portfolio invests.

The price the Master Portfolio could receive upon the sale of any particular portfolio investment may differ from the Master Portfolio’s valuation of the investment, particularly for securities that trade in thin or volatile markets or that are valued using a fair valuation technique or a price provided by an independent pricing service. Changes to significant unobservable inputs and assumptions (i.e., publicly traded company multiples, growth rate, time to exit) due to the lack of observable inputs may significantly impact the resulting fair value and therefore the Master Portfolio’s results of operations. As a result, the price received upon the sale of an investment may be less than the value ascribed by the Master Portfolio, and the Master Portfolio could realize a greater than expected loss or lesser than expected gain upon the sale of the investment. The Master Portfolio’s ability to value its investments may also be impacted by technological issues and/or errors by pricing services or other third party service providers.

Counterparty Credit Risk:The Master Portfolio may be exposed to counterparty credit risk, or the risk that an entity may fail to or be unable to perform on its commitments related to unsettled or open transactions. The Master Portfolio manages counterparty credit risk by entering into transactions only with counterparties that the Manager believes have the financial resources to honor their obligations and by monitoring the financial stability of those counterparties. Financial assets, which potentially expose the Master Portfolio to market, issuer and counterparty credit risks, consist principally of financial instruments and receivables due from counterparties. The extent of the Master Portfolio’s exposure to market, issuer and counterparty credit risks with respect to these financial assets is approximately their value recorded in the Statement of Assets and Liabilities, less any collateral held by the Master Portfolio.

A derivative contract may suffer amark-to-market loss if the value of the contract decreases due to an unfavorable change in the market rates or values of the underlying instrument. Losses can also occur if the counterparty does not perform under the contract.

With exchange-traded futures, there is less counterparty credit risk to the Master Portfolio since the exchange or clearinghouse, as counterparty to such instruments, guarantees against a possible default. The clearinghouse stands between the buyer and the seller of the contract; therefore, credit risk is limited to failure of the clearinghouse. While offset rights may exist under applicable law, the Master Portfolio does not have a contractual right of offset against a clearing broker or clearinghouse

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued)

in the event of a default (including the bankruptcy or insolvency). Additionally, credit risk exists inexchange-traded futures with respect to initial and variation margin that is held in a clearing broker’s customer accounts. While clearing brokers are required to segregate customer margin from their own assets, in the event that a clearing broker becomes insolvent or goes into bankruptcy and at that time there is a shortfall in the aggregate amount of margin held by the clearing broker for all its clients, typically the shortfall would be allocated on a pro rata basis across all the clearing broker’s customers, potentially resulting in losses to the Master Portfolio.

Concentration Risk:The Master Portfolio invests a substantial amount of its assets in issuers located in a single country or a limited number of countries. When the Master Portfolio concentrates its investments in this manner, it assumes the risk that economic, political and social conditions in those countries may have a significant impact on their investment performance. Foreign issuers may not be subject to the same uniform accounting, auditing and financial reporting standards and practices as used in the United States. Foreign securities markets may also be less liquid, more volatile, and less subject to governmental supervision not typically associated with investing in U.S. securities. Investment percentages in specific countries are presented in the Schedule of Investments.

The Master Portfolio invests a significant portion of its assets in securities of issuers located in Europe or with significant exposure to European issuers or countries. The European financial markets have recently experienced volatility and adverse trends due to concerns about economic downturns in, or rising government debt levels of, several European countries. These events may spread to other countries in Europe and may affect the value and liquidity of certain of the Master Portfolio’s investments.

Responses to the financial problems by European governments, central banks and others, including austerity measures and reforms, may not work, may result in social unrest and may limit future growth and economic recovery or have other unintended consequences. Further defaults or restructurings by governments and others of their debt could have additional adverse effects on economies, financial markets and asset valuations around the world. In addition, the United Kingdom has voted to withdraw from the European Union, and one or more other countries may withdraw from the European Union and/or abandon the Euro, the common currency of the European Union. The impact of these actions, especially if they occur in a disorderly fashion, is not clear but could be significant and far reaching.

The Master Portfolio invests a significant portion of its assets in securities of issuers located in Asia or with significant exposure to Asian issuers or countries. The Asian financial markets have recently experienced volatility and adverse trends due to concerns in several Asian countries regarding monetary policy, government intervention in the markets, rising government debt levels or economic downturns. These events may spread to other countries in Asia and may affect the value and liquidity of certain of the Master Portfolio’s investments.

11. SUBSEQUENT EVENTS

Management has evaluated the impact of all subsequent events on the Master Portfolio through the date the financial statements were issued and has determined that there were no subsequent events requiring adjustment or additional disclosure in the financial statements.

NOTESTO FINANCIAL STATEMENTS 19

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of

Master Investment Portfolio and Investors of International Tilts Master Portfolio

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of International Tilts Master Portfolio (one of the series constituting Master Investment Portfolio, referred to hereafter as the “Master Portfolio”) as of December 31, 2019, the related statement of operations for the year ended December 31, 2019, the statements of changes in net assets for each of the two years in the period ended December 31, 2019, including the related notes, and the financial highlights for each of the five years in the period ended December 31, 2019 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Master Portfolio as of December 31, 2019, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended December 31, 2019 and the financial highlights for each of the five years in the period ended December 31, 2019 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Master Portfolio’s management. Our responsibility is to express an opinion on the Master Portfolio’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“PCAOB”) and are required to be independent with respect to the Master Portfolio in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of December 31, 2019 by correspondence with the custodian, transfer agent and brokers. We believe that our audits provide a reasonable basis for our opinion.

/s/PricewaterhouseCoopers LLP

Philadelphia, Pennsylvania

February 27, 2020

We have served as the auditor of one or more BlackRock investment companies since 2000.

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement Regarding Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940, as amended (the “Liquidity Rule”) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Board of Trustees (the “Board”) of Master Investment Portfolio (“MIP”), on behalf of International Tilts Master Portfolio, met on November 12-13, 2019 (the “Meeting”) to review the liquidity risk management program (the “Program”) applicable to the BlackRock open-end funds, excluding money market funds (each, a “Fund”), pursuant to the Liquidity Rule. The Board has appointed BlackRock Advisors, LLC or BlackRock Fund Advisors (“BlackRock”), each an investment adviser to certain Funds, as the program administrator for each Fund’s Program, as applicable. BlackRock has delegated oversight of the Program to the 40 Act Liquidity Risk Management Committee (the “Committee”). At the Meeting, the Committee, on behalf of BlackRock, provided the Board with a report that addressed the operation of the Program and assessed its adequacy and effectiveness of implementation, including the operation of each Fund’s Highly Liquid Investment Minimum (“HLIM”) where applicable, and any material changes to the Program (the “Report”). The Report covered the period from December 1, 2018 through September 30, 2019 (the “Program Reporting Period”).

The Report described the Program’s liquidity classification methodology for categorizing a Fund’s investments (including derivative transactions) into one of four liquidity buckets. It also described BlackRock’s methodology in establishing a Fund’s HLIM and noted that the Committee reviews and ratifies the HLIM assigned to each Fund no less frequently than annually.

The Report noted that the Program complied with the key factors for consideration under the Liquidity Rule for assessing, managing and periodically reviewing a Fund’s liquidity risk, as follows:

A. The Fund’s investment strategy and liquidity of portfolio investments during both normal and reasonably foreseeable stressed conditions:During the Program Reporting Period, the Committee reviewed whether each Fund’s strategy is appropriate for an open-end fund structure with a focus on Funds with more significant and consistent holdings of less liquid and illiquid assets. The Committee also factored a Fund’s concentration in an issuer into the liquidity classification methodology by taking issuer position sizes into account. Where a Fund participated in borrowings for investment purposes (such as tender option bonds and reverse repurchase agreements), such borrowings were factored into the Program’s calculation of a Fund’s liquidity bucketing. Derivative exposure was also considered in such calculation.

B. Short-term and long-term cash flow projections during both normal and reasonably foreseeable stressed conditions:During the Program Reporting Period, the Committee reviewed historical net redemption activity and used this information as a component to establish each Fund’s reasonably anticipated trading size (“RATS”). Each Fund has adopted an in-kind redemption policy which may be utilized to meet larger redemption requests. The Committee may also take into consideration a Fund’s shareholder ownership concentration (which, depending on product type and distribution channel, may or may not be available), a Fund’s distribution channels, and the degree of certainty associated with a Fund’s short-term and long-term cash flow projections.

C. Holdings of cash and cash equivalents, as well as borrowing arrangements:The Committee considered the terms of the credit facility applicable to the Funds, the financial health of the institution providing the facility and the fact that the credit facility is shared among multiple Funds (including that a portion of the aggregate commitment amount is specifically designated for BlackRock Floating Rate Income Portfolio and BlackRock Credit Strategies Income Fund, each a series of BlackRock Funds V). The Committee also considered other types of borrowing available to the Funds, such as the ability to use reverse repurchase agreements and interfund lending, as applicable.

There were no material changes to the Program during the Program Reporting Period. The Report provided to the Board stated that the Committee concluded that based on the operation of the functions, as described in the Report, the Program is operating as intended and is effective in implementing the requirements of the Liquidity Rule.

STATEMENT REGARDING LIQUIDITY RISK MANAGEMENT PROGRAM 21

Trustee and Officer Information

Independent Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Mark Stalnecker 1951	Chair of the Board (Since 2019); Trustee (Since 2015)	Chief Investment Officer, University of Delaware from 1999 to 2013; Trustee and Chair of the Finance and Investment Committees, Winterthur Museum and Country Estate from 2005 to 2016; Member of the Investment Committee, Delaware Public Employees’ Retirement System since 2002; Member of the Investment Committee, Christiana Care Health System from 2009 to 2017; Member of the Investment Committee, Delaware Community Foundation from 2013 to 2014; Director and Chair of the Audit Committee, SEI Private Trust Co. from 2001 to 2014.	37 RICs consisting of 177 Portfolios	None
Bruce R. Bond 1946	Trustee (Since 2019)	Board Member, Amsphere Limited (software) since 2018; Trustee and Member of the Governance Committee, State Street Research Mutual Funds from 1997 to 2005; Board Member of Governance, Audit and Finance Committee, Avaya Inc. (computer equipment) from 2003 to 2007.	37 RICs consisting of 177 Portfolios	None
Susan J. Carter 1956	Trustee (Since 2016)	Director, Pacific Pension Institute from 2014 to 2018; Advisory Board Member, Center for Private Equity and Entrepreneurship at Tuck School of Business since 1997; Senior Advisor, Commonfund Capital, Inc. (“CCI”) (investment adviser) in 2015; Chief Executive Officer, CCI from 2013 to 2014; President & Chief Executive Officer, CCI from 1997 to 2013; Advisory Board Member, Girls Who Invest from 2015 to 2018 and Board Member thereof since 2018; Advisory Board Member, Bridges Fund Management since 2016; Trustee, Financial Accounting Foundation since 2017; Practitioner Advisory Board Member, Private Capital Research Institute (“PCRI”) since 2017.	37 RICs consisting of 177 Portfolios	None
Collette Chilton 1958	Trustee (Since 2015)	Chief Investment Officer, Williams College since 2006; Chief Investment Officer, Lucent Asset Management Corporation from 1998 to 2006.	37 RICs consisting of 177 Portfolios	None
Neil A. Cotty 1954	Trustee (Since 2016)	Bank of America Corporation from 1996 to 2015, serving in various senior finance leadership roles, including Chief Accounting Officer from 2009 to 2015, Chief Financial Officer of Global Banking, Markets and Wealth Management from 2008 to 2009, Chief Accounting Officer from 2004 to 2008, Chief Financial Officer of Consumer Bank from 2003 to 2004, Chief Financial Officer of Global Corporate Investment Bank from 1999 to 2002.	37 RICs consisting of 177 Portfolios	None
Lena G. Goldberg 1949	Trustee (Since 2019)	Senior Lecturer, Harvard Business School, since 2008; Director, Charles Stark Draper Laboratory, Inc. since 2013; FMR LLC/Fidelity Investments (financial services) from 1996 to 2008, serving in various senior roles including Executive Vice President — Strategic Corporate Initiatives and Executive Vice President and General Counsel; Partner, Sullivan & Worcester LLP from 1985 to 1996 and Associate thereof from 1979 to 1985.	37 RICs consisting of 177 Portfolios	None
Robert M. Hernandez 1944	Trustee (Since 2019)	Director, Vice Chairman and Chief Financial Officer of USX Corporation (energy and steel business) from 1991 to 2001; Director andnon-executive Chairman, RTI International Metals, Inc. from 1990 to 2015; Director, TE Connectivity (electronics) from 2006 to 2012.	37 RICs consisting of 177 Portfolios	Chubb Limited (insurance company); Eastman Chemical Company

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information  (continued)

Independent Trustees (a)(continued)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Henry R. Keizer 1956	Trustee (Since 2019)	Director, Park Indemnity Ltd. (captive insurer) since 2010; Director, MUFG Americas Holdings Corporation and MUFG Union Bank, N.A. (financial and bank holding company) from 2014 to 2016; Director, American Institute of Certified Public Accountants from 2009 to 2011; Director, KPMG LLP (audit, tax and advisory services) from 2004 to 2005 and 2010 to 2012; Director, KPMG International in 2012, Deputy Chairman and Chief Operating Officer thereof from 2010 to 2012 and U.S. Vice Chairman of Audit thereof from 2005 to 2010; Global Head of Audit, KPMGI (consortium of KPMG firms) from 2006 to 2010; Director, YMCA of Greater New York from 2006 to 2010.	37 RICs consisting of 177 Portfolios	Hertz Global Holdings (car rental); Montpelier Re Holdings, Ltd. (publicly held property and casualty reinsurance) from 2013 until 2015; Sealed Air Corp. (packaging); WABCO (commercial vehicle safety systems)
Cynthia A. Montgomery 1952	Trustee (Since 2009)	Professor, Harvard Business School since 1989.	37 RICs consisting of 177 Portfolios	Newell Rubbermaid, Inc. (manufacturing)
Donald C. Opatrny 1952	Trustee (Since 2019)	Trustee, Vice Chair, Member of the Executive Committee and Chair of the Investment Committee, Cornell University since 2004; President, Trustee and Member of the Investment Committee, The Aldrich Contemporary Art Museum from 2007 to 2014; Member of the Board and Investment Committee, University School from 2007 to 2018; Member of the Investment Committee, Mellon Foundation from 2009 to 2015; Trustee, Artstor (a Mellon Foundation affiliate) from 2010 to 2015; President and Trustee, the Center for the Arts, Jackson Hole from 2011 to 2018; Director, Athena Capital Advisors LLC (investment management firm) since 2013; Trustee and Chair of the Investment Committee, Community Foundation of Jackson Hole since 2014; Member of Affordable Housing Supply Board of Jackson, Wyoming since 2018; Member, Investment Funds Committee, State of Wyoming since 2017; Trustee, Phoenix Art Museum since 2018.	37 RICs consisting of 177 Portfolios	None
Joseph P. Platt 1947	Trustee (Since 2009)	General Partner, Thorn Partners, LP (private investments) since 1998; Director, WQED Multi-Media (public broadcastingnot-for-profit) since 2001; Chair, Basic Health International(non-profit) since 2015.	37 RICs consisting of 177 Portfolios	Greenlight Capital Re, Ltd. (reinsurance company); Consol Energy Inc.
Kenneth L. Urish 1951	Trustee (Since 2009)	Managing Partner, Urish Popeck & Co., LLC (certified public accountants and consultants) since 1976; Past-Chairman of the Professional Ethics Committee of the Pennsylvania Institute of Certified Public Accountants and Committee Member thereof since 2007; Member of External Advisory Board, The Pennsylvania State University Accounting Department since founding in 2001; Principal, UP Strategic Wealth Investment Advisors, LLC since 2013; Trustee, The Holy Family Institute from 2001 to 2010; President and Trustee, Pittsburgh Catholic Publishing Associates from 2003 to 2008; Director,Inter-Tel from 2006 to 2007.	37 RICs consisting of 177 Portfolios	None
Claire A. Walton 1957	Trustee (Since 2016)	Chief Operating Officer and Chief Financial Officer of Liberty Square Asset Management, LP from 1998 to 2015; General Partner of Neon Liberty Capital Management, LLC since 2003; Director, Boston Hedge Fund Group from 2009 to 2018; Director, Woodstock Ski Runners since 2013; Director, Massachusetts Council on Economic Education from 2013 to 2015.	37 RICs consisting of 177 Portfolios	None

TRUSTEEAND OFFICER INFORMATION 23

Trustee and Officer Information  (continued)

Interested Trustees (a)(d)
Name Year of Birth (b)	Position(s) Held (Length of Service) (c)	Principal Occupation(s) During Past Five Years	Number of BlackRock-Advised Registered Investment Companies (“RICs”) Consisting of Investment Portfolios (“Portfolios”) Overseen	Public Company and Other Investment Company Directorships Held During Past Five Years
Robert Fairbairn 1965	Trustee (Since 2018)	Vice Chairman of BlackRock, Inc. since 2019; Member of BlackRock’s Global Executive and Global Operating Committees;Co-Chair of BlackRock’s Human Capital Committee; Senior Managing Director of BlackRock, Inc. from 2010 to 2019; oversaw BlackRock’s Strategic Partner Program and Strategic Product Management Group from 2012 to 2019; Member of the Board of Managers of BlackRock Investments, LLC from 2011 to 2018; Global Head of BlackRock’s Retail and iShares® businesses from 2012 to 2016.	123 RICs consisting of 287 Portfolios	None
John M. Perlowski (e) 1964	Trustee (Since 2015); President and Chief Executive Officer (Since 2010)	Managing Director of BlackRock, Inc. since 2009; Head of BlackRock Global Accounting and Product Services since 2009; Advisory Director of Family Resource Network (charitable foundation) since 2009.	124 RICs consisting of 288 Portfolios	None
(a) The address of each Trustee is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Independent Trustee serve until their resignation, retirement, removal or death, or until December 31 of the year in which they turn 75. The Board may determine to extend the terms of Independent Trustees on acase-by-case basis, as appropriate. (c) In connection with the acquisition of Barclays Global Investors by BlackRock, Inc. in December 2009, certain Independent Trustees were elected to the Board. Furthermore, effective January 1, 2019, three BlackRock Fund Complexes were realigned and consolidated into two BlackRock Fund Complexes. As a result, although the chart shows the year that each Independent Trustee joined the Board, certain Independent Trustees first became members of the boards of other BlackRock-advised Funds or legacy BlackRock funds as follows: Bruce R. Bond, 2005; Robert M. Hernandez, 1996; Cynthia A. Montgomery, 1994; Joseph P. Platt, 1999; Kenneth L. Urish, 1999; Lena G. Goldberg, 2016; Henry R. Keizer, 2016; Donald C. Opatrny, 2015. (d) Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of MIP based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Fixed-Income Complex. (e) Mr. Perlowski is also a trustee of the BlackRock Credit Strategies Fund.

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Trustee and Officer Information(continued)

Officers Who Are Not Trustees (a)
Name Year of Birth (b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
Thomas Callahan 1968	Vice President (Since 2016)	Managing Director of BlackRock, Inc. since 2013; Member of the Board of Managers of BlackRock Investments, LLC (principal underwriter) since 2019 and Managing Director thereof since 2017; Head of BlackRock’s Global Cash Management Business since 2016;Co-Head of the Global Cash Management Business from 2014 to 2016; Deputy Head of the Global Cash Management Business from 2013 to 2014; Member of the Cash Management Group Executive Committee since 2013; Chief Executive Officer of NYSE Liffe U.S. from 2008 to 2013.
Jennifer McGovern 1977	Vice President (Since 2014)	Managing Director of BlackRock, Inc. since 2016; Director of BlackRock, Inc. from 2011 to 2015; Head of Product Development and Oversight for BlackRock’s Strategic Product Management Group since 2019; Head of Product Structure and Oversight for BlackRock’s U.S. Wealth Advisory Group from 2013 to 2019.
Neal J. Andrews 1966	Chief Financial Officer (Since 2009)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2009)	Managing Director of BlackRock, Inc. since 2007.
Charles Park 1967	Chief Compliance Officer (Since 2014)	Anti-Money Laundering Compliance Officer for certain BlackRock-advised Funds from 2014 to 2015; Chief Compliance Officer of BlackRock Advisors, LLC and the BlackRock-advised Funds in the BlackRock Multi-Asset Complex and the BlackRock Fixed-Income Complex since 2014; Principal of and Chief Compliance Officer for iShares® Delaware Trust Sponsor LLC since 2012 and BlackRock Fund Advisors (“BFA”) since 2006; Chief Compliance Officer for theBFA-advised iShares® exchange traded funds since 2006; Chief Compliance Officer for BlackRock Asset Management International Inc. since 2012.
Lisa Belle 1968	Anti-Money Laundering Compliance Officer (Since 2019)	Managing Director of BlackRock, Inc. since 2019; Global Financial Crime Head for Asset and Wealth Management of JP Morgan from 2013 to 2019; Managing Director of RBS Securities from 2012 to 2013; Head of Financial Crimes for Barclays Wealth Americas from 2010 to 2012.
Janey Ahn 1975	Secretary (Since 2019)	Managing Director of BlackRock, Inc. since 2018; Director of BlackRock, Inc. from 2009 to 2017.
(a) The address of each Officer is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055. (b) Officers of MIP serve at the pleasure of the Board.

Further information about MIP’s Trustees and Officers is available in the Master Portfolio’s Statement of Additional Information, which can be obtained without charge by calling (800)441-7762.

Effective September 19, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of MIP.

Effective September 19, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of MIP.

Effective December 31, 2019, Robert M. Hernandez retired as Trustee of MIP.

Investment Adviser and Administrator

BlackRock Advisors, LLC

Wilmington, DE 19809

Sub-Advisers

BlackRock Fund Advisors

San Francisco, CA 94105

BlackRock International Limited

Edinburgh EH3 8BL, United Kingdom

Accounting Agent and Custodian

State Street Bank and Trust Company

Boston, MA 02111

Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP

Philadelphia, PA 19103

Legal Counsel

Sidley Austin LLP

New York, NY 10019

Address of MIP

400 Howard Street

San Francisco, CA 94105

TRUSTEEAND OFFICER INFORMATION 25

Additional Information

Availability of Quarterly Schedule of Investments

The Master Portfolio files its complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports onForm N-PORT, and for reporting periods ended prior to March 31, 2019, filed such information onForm N-Q. The Master Portfolio’s Forms N-PORT andN-Q are available on the SEC’s website at sec.gov. The Master Portfolio’s FormN-Q may also be obtained upon request and without charge by calling(800) 441-7762.

Availability of Proxy Voting Policies and Procedures

A description of the policies and procedures that the Master Portfolio uses to determine how to vote proxies relating to portfolio securities is available upon request and without charge (1) by calling(800) 441-7762; (2) atblackrock.com; and (3) on the SEC’s website at sec.gov.

Availability of Proxy Voting Record

Information about how the Master Portfolio voted proxies relating to securities held in the Master Portfolio’s portfolio during the most recent12-month period ended June 30 is available upon request and without charge (1) atblackrock.com or by calling(800) 441-7762 and (2) on the SEC’s website at sec.gov.

ADDITIONAL INFORMATION 26

Item 2 –	Code of Ethics – Each registrant (or each, a “Fund”) has adopted a code of ethics, as of the end of the period covered by this report, applicable to the registrants’ principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. During the period covered by this report, the code of ethics was amended to update certain information and to make othernon-material changes. During the period covered by this report, there have been no waivers granted under the code of ethics. The registrants undertake to provide a copy of the code of ethics to any person upon request, without charge, who calls1-800-441-7762.
Item 3 –	Audit Committee Financial Expert – Each registrant’s board of directors (the “board of directors”), has determined that (i) the registrant has the following audit committee financial expert serving on its audit committee and (ii) each audit committee financial expert is independent:
	Neil A. Cotty Robert M. Hernandez Henry R. Keizer Kenneth L. Urish Claire A. Walton
	Under applicable securities laws, a person determined to be an audit committee financial expert will not be deemed an “expert” for any purpose, including without limitation for the purposes of Section 11 of the Securities Act of 1933, as a result of being designated or identified as an audit committee financial expert. The designation or identification of a person as an audit committee financial expert does not impose on such person any duties, obligations, or liabilities greater than the duties, obligations, and liabilities imposed on such person as a member of the audit committee and board of directors in the absence of such designation or identification. The designation or identification of a person as an audit committee financial expert does not affect the duties, obligations, or liability of any other member of the audit committee or board of directors.

Item 4 –	Principal Accountant Fees and Services
	The following table presents fees billed by PricewaterhouseCoopers LLP (“PwC”) in each of the last two fiscal years for the services rendered to the Funds:

	(a) Audit Fees		(b) Audit-Related Fees1		(c) Tax Fees2		(d) All Other Fees
Entity Name	Current     Fiscal Year     End	Previous     Fiscal Year     End	Current Fiscal   Year End	Previous Fiscal     Year End	Current Fiscal     Year End	Previous Fiscal   Year End	Current Fiscal   Year End	Previous Fiscal   Year End
BlackRock Cash Funds: Institutional	$11,000	$11,000	$0	$0	$2,900	$2,900	$0	$0
BlackRock Cash Funds: Treasury	$11,000	$11,000	$0	$0	$2,900	$2,900	$0	$0
BlackRock LifePath Dynamic Retirement Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2025 Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2030 Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2035 Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2040 Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2045 Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2050 Fund	$11,000	$11,023	$0	$0	$8,100	$8,100	$0	$0

3

BlackRock LifePath Dynamic 2055 Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
BlackRock LifePath Dynamic 2060 Fund	$11,000	$9,921	$0	$0	$8,100	$8,100	$0	$0
Blackrock LifePath Dynamic 2065 Fund	$9,900	N/A	$0	N/A	$11,000	N/A	$0	N/A
iShares MSCI Total International Index Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
iShares Russell 1000Large-Cap Index Fund	$11,000	$11,000	$0	$0	$8,100	$8,100	$0	$0
iShares S&P 500 Index Fund	$12,200	$11,000	$0	$0	$8,100	$8,100	$0	$0
iShares U.S. Aggregate Bond Index Fund	$12,200	$11,000	$0	$0	$8,100	$8,100	$0	$0
Active Stock Master Portfolio	$22,000	$22,000	$0	$0	$20,700	$20,700	$0	$0
International Tilts Master Portfolio	$22,000	$22,000	$0	$0	$15,600	$15,600	$0	$0
Large Cap Index Master Portfolio	$22,000	$22,000	$0	$0	$17,600	$15,600	$0	$0
LifePath Dynamic Retirement Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2025 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2030 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2035 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2040 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2045 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2050 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2055 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2060 Master Portfolio	$15,300	$15,300	$0	$0	$15,600	$15,600	$0	$0
LifePath Dynamic 2065 Master Portfolio	$13,770	N/A	$0	N/A	$0	N/A	$0	N/A
Money Market Master Portfolio	$12,400	$12,400	$0	$0	$0	$0	$0	$0
S&P 500 Index Master Portfolio	$22,000	$20,000	$0	$0	$15,600	$15,600	$0	$0
Total International ex U.S. Index Master Portfolio	$22,000	$22,000	$0	$0	$15,600	$15,600	$0	$0
Treasury Money Market Master Portfolio	$12,400	$12,400	$0	$0	$7,100	$7,100	$0	$0
U.S. Total Bond Index Master Portfolio	$24,100	$24,100	$0	$0	$17,600	$15,600	$0	$0

The following table presents fees billed by PwC that were required to be approved by each registrant’s audit committee (each a “Committee”) for services that relate directly to the operations or financial reporting of each Fund and that are rendered on behalf of BlackRock Advisors, LLC (the “investment adviser” or “BlackRock”) and entities controlling, controlled by, or under common control with BlackRock (not including anysub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) that provide ongoing services to each Fund (“Affiliated Service Providers”):

	Current Fiscal Year End	Previous Fiscal Year  End
(b) Audit-Related Fees1	$0	$0
(c) Tax Fees2	$0	$0
(d) All Other Fees3	$0	$0

4

¹ The nature of the services includes assurance and related services reasonably related to the performance of the audit or review of financial statements not included in Audit Fees, including accounting consultations, agreed-upon procedure reports, attestation reports, comfort letters,out-of-pocket expenses and internal control reviews not required by regulators.

² The nature of the services includes tax compliance and/or tax preparation, including services relating to the filing or amendment of federal, state or local income tax returns, regulated investment company qualification reviews, taxable income and tax distribution calculations.

³ Aggregate fees borne by BlackRock in connection with the review of compliance procedures and attestation thereto performed by PwC with respect to all of the registeredclosed-end funds and some of the registeredopen-end funds advised by BlackRock.

(e)(1) Audit CommitteePre-Approval Policies and Procedures:

Each Committee has adopted policies and procedures with regard to thepre-approval of services. Audit, audit-related and tax compliance services provided to the registrant on an annual basis require specificpre-approval by the registrant’s Committee. The Committee also must approve othernon-audit services provided to the registrant and thosenon-audit services provided to the Investment Adviser and Affiliated Service Providers that relate directly to the operations and the financial reporting of the registrant. Certain of thesenon-audit services that the Committee believes are (a) consistent with the SEC’s auditor independence rules and (b) routine and recurring services that will not impair the independence of the independent accountants may be approved by the Committee without consideration on a specificcase-by-case basis (“generalpre-approval”). The term of any generalpre-approval is 12 months from the date of thepre-approval, unless the Committee provides for a different period. Tax or othernon-audit services provided to the registrant which have a direct impact on the operations or financial reporting of the registrant will only be deemedpre-approved provided that any individual project does not exceed $10,000 attributable to the registrant or $50,000 per project. For this purpose, multiple projects will be aggregated to determine if they exceed the previously mentioned cost levels.

Any proposed services exceeding thepre-approved cost levels will require specificpre-approval by the registrant’s Committee, as will any other services not subject to generalpre-approval (e.g., unanticipated but permissible services). The Committee is informed of each service approved subject to generalpre-approval at the next regularly scheduledin-person board meeting. At this meeting, an analysis of such services is presented to the Committee for ratification. The Committee may delegate to the Committee Chairman the authority to approve the provision of and fees for any specific engagement of permittednon-audit services, including services exceedingpre-approved cost levels.

(e)(2) None of the services described in each of Items 4(b) through (d) were approved by either Committee pursuant to the de minimus exception in paragraph (c)(7)(i)(C) of Rule2-01 of RegulationS-X.

(f) Not Applicable

(g) The aggregatenon-audit fees, defined as the sum of the fees shown under “Audit-Related Fees,” “Tax Fees” and “All Other Fees,” paid to the accountant for services rendered by the accountant to the registrant, the Investment Adviser and the Affiliated Service Providers were:

Entity Name	Current   Fiscal   Year End	Previous   Fiscal Year   End
BlackRock Cash Funds: Institutional	$2,900	$2,900
BlackRock Cash Funds: Treasury	$2,900	$2,900
BlackRock LifePath Dynamic Retirement Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2025 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2030 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2035 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2040 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2045 Fund	$8,100	$8,100

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BlackRock LifePath Dynamic 2050 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2055 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2060 Fund	$8,100	$8,100
BlackRock LifePath Dynamic 2065 Fund	$11,000	N/A
iShares MSCI Total International Index Fund	$8,100	$8,100
iShares Russell 1000Large-Cap Index Fund	$8,100	$8,100
iShares S&P 500 Index Fund	$8,100	$8,100
iShares U. S. Aggregate Bond Index Fund	$8,100	$8,100
Active Stock Master Portfolio	$20,700	$20,700
International Tilts Master Portfolio	$15,600	$15,600
Large Cap Index Master Portfolio	$17,600	$15,600
LifePath Dynamic Retirement Master Portfolio	$15,600	$15,600
LifePath Dynamic 2025 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2030 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2035 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2040 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2045 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2050 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2055 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2060 Master Portfolio	$15,600	$15,600
LifePath Dynamic 2065 Master Portfolio	$0	N/A
Money Market Master Portfolio	$0	$0
S&P 500 Index Master Portfolio	$15,600	$15,600
Total International ex U.S. Index Master Portfolio	$15,600	$15,600
Treasury Money Market Master Portfolio	$7,100	$7,100
U.S. Total Bond Index Master Portfolio	$17,600	$15,600

(h) Each Committee has considered and determined that the provision ofnon-audit services that were rendered to the Investment Adviser and the Affiliated Service Providers that were notpre-approved pursuant to paragraph (c)(7)(ii) ofRule 2-01 of RegulationS-X is compatible with maintaining the principal accountant’s independence.

Item 5 – Audit Committee of Listed Registrants – Not Applicable

Item 6 – Investments

(a) The registrants’ Schedules of Investments are included as part of the Report to Stockholders filed under Item 1 of this Form.

(b) Not Applicable due to no such divestments during the semi-annual period covered since the previous FormN-CSR filing.

Item 7 – Disclosure of Proxy Voting Policies and Procedures forClosed-End Management Investment Companies – Not Applicable

Item 8 – Portfolio Managers ofClosed-End Management Investment Companies – Not Applicable

Item 9 – Purchases of Equity Securities byClosed-End Management Investment Company and Affiliated Purchasers – Not Applicable

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Item 10 – Submission of Matters to a Vote of Security Holders – There have been no material changes to these procedures.

Item 11 – Controls and Procedures

(a) – The registrants’ principal executive and principal financial officers, or persons performing similar functions, have concluded that the registrants’ disclosure controls and procedures (as defined in Rule30a-3(c) under the Investment Company Act of 1940, as amended (the “1940 Act”)) are effective as of a date within 90 days of the filing of this report based on the evaluation of these controls and procedures required by Rule30a-3(b) under the 1940 Act and Rule 15(d)-15(b) under the Securities Exchange Act of 1934, as amended.

(b) – There were no changes in the registrants’ internal control over financial reporting (as defined in Rule30a-3(d) under the 1940 Act) that occurred during the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrants’ internal control over financial reporting.

Item 12 – Disclosure of Securities Lending Activities forClosed-End Management Investment Companies – Not Applicable to the registrants.

Item 13 – Exhibits attached hereto

(a)(1) Code of Ethics – See Item 2

(a)(2) Certifications – Attached hereto

(a)(3) Not Applicable

(a)(4) Not Applicable

(b) Certifications – Attached hereto

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Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, each registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.
BlackRock Funds III and Master Investment Portfolio
By:	/s/ John M. Perlowski
	John M. Perlowski
	Chief Executive Officer (principal executive officer) of
	BlackRock Funds III and Master Investment Portfolio
Date: March 6, 2020
Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of each registrant and in the capacities and on the dates indicated.
By:	/s/ John M. Perlowski
	John M. Perlowski
	Chief Executive Officer (principal executive officer) of
	BlackRock Funds III and Master Investment Portfolio
Date: March 6, 2020
By:	/s/ Neal J. Andrews
	Neal J. Andrews
	Chief Financial Officer (principal financial officer) of
	BlackRock Funds III and Master Investment Portfolio
Date: March 6, 2020

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