Blackrock Bond Fund 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:811-02857 and811-21434

Name of Fund: BlackRock Total Return Fund of BlackRock Bond Fund, Inc. and Master Total Return Portfolio of Master Bond LLC

Fund Address:    100 Bellevue Parkway, Wilmington, DE 19809

Name and address of agent for service: John M. Perlowski, Chief Executive Officer, BlackRock Total Return Fund of BlackRock Bond Fund, Inc. and Master Total Return Portfolio of Master Bond LLC, 55 East 52^nd Street, New York, NY 10055

Registrants’ telephone number, including area code: (800)441-7762

Date of fiscal year end: 09/30/2019

Date of reporting period: 09/30/2019

Item 1 – Report to Stockholders

SEPTEMBER 30, 2019

2019 Annual Report

BlackRock Bond Fund, Inc.

· BlackRock Total Return 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 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,

Investment performance in the 12 months ended September 30, 2019 was a tale of two markets. The first half of the reporting period was characterized by restrictive monetary policy, deteriorating economic growth, equity market volatility, and rising fear of an imminent recession. During the second half of the reporting period, stocks and bonds rebounded sharply, as influential central banks shifted toward accommodative monetary policy, which led to broad-based optimism that a near-term recession could be averted.

After the dust settled, equity and bond markets posted mixed returns while weathering significant volatility. Less volatile U.S. large cap equities and U.S. bonds advanced, while equities at the high end of the risk spectrum — emerging markets, international developed, and U.S. small cap — posted modest negative returns.

Fixed-income securities delivered strong returns with relatively low volatility, as interest rates declined (and bond prices rose). U.S. Treasuries, particularly long-term Treasuries, proved to be an effective ballast for diversified investors. Investment grade and high yield corporate bonds also posted positive returns, as the credit fundamentals in corporate markets remained relatively solid.

In the U.S. equity market, volatility spiked in late 2018, as a wide range of risks were brought to bear on markets, ranging from rising interest rates and slowing global growth to heightened trade tensions and political turmoil. Volatility also rose in emerging markets, as the appreciating U.S. dollar and higher interest rates in the U.S. disrupted economic growth abroad. An economic slowdown in Europe and ongoing uncertainty about Brexit led to negative performance for European equities.

As equity performance faltered and global economic growth slowed, the U.S. Federal Reserve (the “Fed”) shifted to a more patient perspective on the economy in January 2019. The Fed left interest rates unchanged for six months, then reduced interest rates twice thereafter. 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, markets are pricing in additional rate cuts by the Fed over the next year, as investors anticipate a steady shift toward more stimulative monetary policy.

We continue to expect a slowing expansion with additional room to run. Despite a sharp slowdown in trade and manufacturing across the globe, U.S. consumers continued to spend at a relatively healthy pace, benefitting from the lowest unemployment rate in 50 years and rising wages. However, escalating trade tensions and the resulting disruptions in global supply chains are becoming increasingly unpredictable, as are geopolitical tensions in the Middle East.

We believe U.S. equities remain relatively attractive, but we are shifting to a more cautious stance within emerging markets and Asia ex-Japan equities. For bonds, U.S. Treasuries are likely to continue to help buffer against volatility in risk assets, while income from other types of bonds can continue to offer steady returns.

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.comfor 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 September 30, 2019
	6-month	12-month
U.S. large cap equities (S&P 500® Index)	6.08%	4.25%
U.S. small cap equities (Russell 2000® Index)	(0.36)	(8.89)
International equities (MSCI Europe, Australasia, Far East Index)	2.57	(1.34)
Emerging market equities (MSCI Emerging Markets Index)	(3.66)	(2.02)
3-month Treasury bills (ICE BofAML 3-Month U.S. Treasury Bill Index)	1.20	2.39
U.S. Treasury securities (ICE BofAML 10-Year U.S. Treasury Index)	7.54	15.15
U.S. investment grade bonds (Bloomberg Barclays U.S. Aggregate Bond Index)	5.42	10.30
Tax-exempt municipal bonds (S&P Municipal Bond Index)	3.71	8.19
U.S. high yield bonds (Bloomberg Barclays U.S. Corporate High Yield 2% Issuer Capped Index)	3.87	6.35
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 PAGE IS NOT PART OF YOUR FUND REPORT

Table of Contents

	Page
The Markets in Review		2
Annual Report:
Fund Summary		4
Disclosure of Expenses		6
The Benefits and Risks of Leveraging		7
Derivative Financial Instruments		7
About Fund Performance		8
Fund Financial Statements:
Statement of Assets and Liabilities		9
Statement of Operations		10
Statements of Changes in Net Assets		11
Fund Financial Highlights		12
Fund Notes to Financial Statements		21
Fund Report of Independent Registered Public Accounting Firm		27
Important Tax Information		27
Master Portfolio Information		28
Master Portfolio Consolidated Financial Statements:
Schedule of Investments		29
Statement of Assets and Liabilities		100
Consolidated Statement of Operations		101
Consolidated Statements of Changes in Net Assets		102
Master Portfolio Consolidated Financial Highlights		103
Master Portfolio Notes to Consolidated Financial Statements		104
Master Portfolio Report of Independent Registered Public Accounting Firm		117
Disclosure of Investment Advisory Agreements and Sub-Advisory Agreements		118
Director and Officer Information		122
Additional Information		125
Glossary of Terms Used in this Report		127

3

Fund Summary as of September 30, 2019 BlackRock Total Return Fund

Investment Objective

BlackRock Total Return Fund’s (the “Fund”)investment objective is to realize a total return that exceeds that of the Bloomberg Barclays U.S. Aggregate Bond Index.

Portfolio Management Commentary

How did the Fund perform?

For the 12-month period ended September 30, 2019, through its investment in Master Total Return Portfolio (the “Master Portfolio”), the Fund’s Class K Shares matched the performance of its benchmark, the Bloomberg Barclays U.S. Aggregate Bond Index, while all other share classes of the Fund underperformed.

What factors influenced performance?

During the period, the Master Portfolio’s overweight to investment grade corporate credit contributed positively to performance. Exposure to municipal bonds also added to relative performance. In addition, the Master Portfolio’s duration positioning (sensitivity to changes in interest rates) contributed positively as Treasury yields declined over the period. Finally, within securitized assets, allocations to collateralized loan obligations (“CLOs”) and non-agency mortgage-backed securities contributed positively to performance.

The Master Portfolio’s non-benchmark allocation to European corporate credit detracted from Fund performance, as did an overweight exposure to agency mortgage-backed securities (“MBS”). Lastly, the Master Portfolio’s global rates exposure and small active currency positioning under macro-oriented strategies detracted from Fund returns.

Describe recent portfolio activity.

During the fourth quarter of 2018, the Master Portfolio’s overweight in duration was reduced, while exposure was rotated further out the yield curve. On the view that slowing economic growth and a near-neutral rate policy by the Fed was anticipated to keep U.S. interest rates range-bound in the near term, the Master Portfolio added to sectors that should benefit from more accommodative monetary policy, such as agency MBS and municipals, as well as local-currency emerging market debt. The Master Portfolio also used this opportunity to rotate from floating-rate to fixed-rate exposure in lower quality credits, reducing floating rate loan interest (or bank loan) exposure in favor of high yield bonds, while also adding to investment grade credits for high quality income. Despite broader market weakness during the fourth quarter, securitized assets performed well, and the Master Portfolio took profits there.

Coming into 2019, risk assets rebounded sharply, and during the first half of the year, the Master Portfolio’s overweight in duration was modestly increased, while exposure was shifted slightly toward longer-dated issues. Following the aggressive re-pricing of risk assets in late 2018, the investment adviser used the opportunity to add to the Master Portfolio’s overweight in investment grade credits. The Master Portfolio also added tactically to its emerging market position as the dovish Fed took pressure off the U.S. dollar, allowing for easier local monetary policy within emerging countries. Given the decline in interest rates and pick-up in mortgage prepayment speeds, the Master Portfolio shifted to an underweight position in agency MBS, while maintaining diversified exposure in securitized assets.

During the third quarter of 2019, the Master Portfolio’s duration was increased slightly to a modest overweight versus the benchmark. Globally, the Master Portfolio marginally increased allocations in non-U.S. sovereign bonds that should benefit from a more accommodative monetary policy from the European Central Bank (“ECB”). Within spread sectors, the Master Portfolio emphasized high quality “carry” assets (i.e., low risk, income-generating assets) given trade uncertainties and the slowdown in global growth. In particular, an overweight position in agency MBS was increased based on attractive valuations. Lastly, the Master Portfolio slightly reduced its overweight to investment grade credit in anticipation of heavy issuance in September, while maintaining a preference for high quality, less cyclical names within the sector.

Describe portfolio positioning at period end.

At period end, the Master Portfolio was positioned with an overweight in duration versus the benchmark as geopolitical uncertainty continued to pressure interest rates lower. The Master Portfolio had non-benchmark exposure to interest rates in European peripheral markets that should benefit from ECB accommodation. In addition, the Master Portfolio held an overweight in agency MBS given attractive valuations, as well as elevated demand from banks and other institutions. The Master Portfolio maintained an overweight in investment grade credit as well. Finally, within a modest emerging market position, the Master Portfolio preferred local currency exposure as many emerging market central banks are expected to cut interest rates, along with select corporate credit positions.

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  (continued) BlackRock Total Return Fund

TOTAL RETURN BASED ON A $10,000 INVESTMENT

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

^(b)  The Fund invests all of its assets in the Master Portfolio. The Master Portfolio typically invests more than 90% of its assets in a diversified portfolio of fixed-income securities such as corporate bonds and notes, mortgage-backed securities, asset-backed securities, convertible securities, preferred securities and government obligations. Under normal circumstances, the Master Portfolio invests at least 80% of its assets in bonds and invests primarily in investment grade fixed-income securities.

^(c)  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.

Performance Summary for the Period Ended September 30, 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		2.70	%		2.66	%		5.61	%		10.23	%		N/A			3.60	%		N/A			4.97	%		N/A
Service		2.41			2.41			5.36			9.80			N/A			3.30			N/A			4.69			N/A
Investor A		2.27			2.27			5.43			9.85			5.46	%		3.27			2.43	%		4.64			4.21	%
Investor A1		2.55			2.54			5.53			10.06			N/A			3.46			N/A			4.84			N/A
Investor C		1.71			1.66			5.09			9.14			8.14			2.59			2.59			3.97			3.97
Investor C1		1.78			1.70			5.13			9.18			N/A			2.67			N/A			4.05			N/A
Investor C2		2.11			1.91			5.21			9.49			N/A			2.99			N/A			4.32			N/A
Class K		2.76			2.76			5.65			10.30			N/A			3.66			N/A			5.07			N/A
Class R		2.11			2.11			5.30			9.58			N/A			3.01			N/A			4.38			N/A
Bloomberg Barclays U.S. Aggregate Bond Index		—			—			5.42			10.30			N/A			3.38			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 8 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.

FUND SUMMARY 5

Disclosure of Expenses BlackRock Total Return Fund

Shareholders of the Fund may incur the following charges: (a) transactional expenses, such as sales charges; and (b) operating expenses, including investment advisory 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 April 1, 2019 and held through September 30, 2019) are 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 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 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 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 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 Example

	Actual									Hypothetical(b)
	Beginning Account Value (04/01/19)			Ending Account Value (09/30/19)			Expenses Paid During the Period(a)			Beginning Account Value (04/01/19)			Ending Account Value (09/30/19)			Expenses Paid During the Period(a)			Annualized Expense Ratio
Institutional		$	1,000.00		$	1,056.10		$	2.27		$	1,000.00		$	1,022.86		$	2.23		0.44	%
Service			1,000.00			1,053.60			3.80			1,000.00			1,021.37			3.74		0.74
Investor A			1,000.00			1,054.30			4.01			1,000.00			1,021.16			3.95		0.78
Investor A1			1,000.00			1,055.30			3.04			1,000.00			1,022.11			2.99		0.59
Investor C			1,000.00			1,050.90			7.40			1,000.00			1,017.85			7.28		1.44
Investor C1			1,000.00			1,051.30			6.99			1,000.00			1,018.25			6.88		1.36
Investor C2			1,000.00			1,052.10			5.30			1,000.00			1,019.90			5.22		1.03
Class K			1,000.00			1,056.50			1.90			1,000.00			1,023.22			1.87		0.37
Class R			1,000.00			1,053.00			5.30			1,000.00			1,019.90			5.22		1.03

^(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 183/365 (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.

6 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

The Benefits and Risks of Leveraging BlackRock Total Return Fund

The Master Portfolio may utilize leverage to seek to enhance returns and net asset value (“NAV”). However, there is no guarantee that these objectives can be achieved in all interest rate environments.

The Master Portfolio may utilize leverage through a credit facility. In general, the concept of leveraging is based on the premise that the financing cost of leverage, which is based on short-term interest rates, is normally lower than the income earned by the Master Portfolio on its longer-term portfolio investments purchased with the proceeds from leverage. To the extent that the total assets of the Master Portfolio (including the assets obtained from leverage) are invested in higher-yielding portfolio investments, the Master Portfolio’s investors benefit from the incremental net income.

The interest earned on securities purchased with the proceeds from leverage is distributed to the Master Portfolio’s investors, and the value of these portfolio holdings is reflected in the Master Portfolio’s NAV. However, in order to benefit investors, the return on assets purchased with leverage proceeds must exceed the ongoing costs associated with the leverage. If interest and other ongoing costs of leverage exceed the Master Portfolio’s return on assets purchased with leverage proceeds, income to investors is lower than if the Master Portfolio had not used leverage.

Furthermore, the value of the Master Portfolio’s investments generally varies inversely with the direction of long-term interest rates, although other factors can also influence the value of portfolio investments. As a result, changes in interest rates can influence the Master Portfolio’s NAV positively or negatively in addition to the impact on the Master Portfolio’s performance from leverage. Changes in the direction of interest rates are difficult to predict accurately, and there is no assurance that the Master Portfolio’s leveraging strategy will be successful.

The use of leverage also generally causes greater changes in the Master Portfolio’s NAV and dividend rates than comparable portfolios without leverage. In a declining market, leverage is likely to cause a greater decline in the NAV of the Master Portfolio’s shares than if the Master Portfolio were not leveraged. In addition, the Master Portfolio may be required to sell portfolio securities at inopportune times or at distressed values in order to comply with regulatory requirements applicable to the use of leverage or as required by the terms of the leverage instruments, which may cause the Master Portfolio to incur losses. The use of leverage may limit the Master Portfolio’s ability to invest in certain types of securities or use certain types of hedging strategies. The Master Portfolio incurs expenses in connection with the use of leverage, all of which are borne by the Master Portfolio’s investors and may reduce income.

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 Consolidated Financial Statements.

THE BENEFITSAND RISKSOF LEVERAGINGAND DERIVATIVE FINANCIAL INSTRUMENTS 7

About Fund Performance BlackRock Total Return Fund

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.

Service Sharesare not subject to any sales charge. These shares are subject to a service fee of 0.25% per year (but no distribution fee) and are available only to certain eligible investors.

Investor A Sharesare 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). 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 A1 Sharesare subject to a maximum initial sales charge (front-end load) of 1.00% and a service fee of 0.10% per year (but no distribution fee). The maximum initial sales charge does not apply to current eligible shareholders of Investor A1 Shares of the Fund. Certain redemptions of these shares may be subject to a CDSC where no initial sales charge was paid at the time of purchase. However, the CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through the reinvestment of dividends and capital gains by existing shareholders.

Investor C Sharesare 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. Effective November 8, 2018, the Fund adopted an automatic conversion feature whereby Investor C Shares held for approximately ten years will be automatically converted into Investor A Shares.

Investor C1 Sharesare subject to a 1.00% CDSC if redeemed within one year of purchase. However, the CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through the reinvestment of dividends and capital gains by existing shareholders. In addition, these shares are subject to a distribution fee of 0.55% per year and a service fee of 0.25% per year. Effective November 8, 2018, the Fund adopted an automatic conversion feature whereby Investor C1 Shares held for approximately ten years will be automatically converted into Investor A Shares.

Investor C2 Sharesare subject to a 1.00% CDSC if redeemed within one year of purchase. However, the CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through the reinvestment of dividends and capital gains by existing shareholders. In addition, these shares are subject to a distribution fee of 0.25% per year and a service fee of 0.25% per year. Effective November 8, 2018, the Fund adopted an automatic conversion feature whereby Investor C2 Shares held for approximately ten years will be automatically converted into Investor A Shares.

Class R Sharesare 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.

Investor A1, Investor C1 and Investor C2 Shares are only available for dividend and capital gain reinvestment by existing shareholders, and for purchase by 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 towww.blackrock.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 tables on the previous page assume reinvestment of all distributions, if any, at net asset value (“NAV”) on the ex-dividend/payable 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 “Manager”), the Fund’s investment adviser, 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 waivers, the Manager 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.

8 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Assets and Liabilities

September 30, 2019

	BlackRock Total Return Fund
ASSETS
Investments at value — Master Portfolio	$	14,908,898,447
Receivables:
Capital shares sold		61,127,312
From the Manager		217,237
Prepaid expenses		356,317
Total assets		14,970,599,313
LIABILITIES
Payables:
Board realignment and consolidation		12,513
Capital shares redeemed		53,080,162
Contributions to the Master Portfolio		8,047,150
Income dividend distributions		6,614,851
Investment advisory fees		3,508,431
Officer’s fees		10,647
Other accrued expenses		2,467,240
Other affiliates		233,056
Service and distribution fees		643,986
Total liabilities		74,618,036
NET ASSETS	$	14,895,981,277
NET ASSETS CONSIST OF
Paid-in capital	$	14,622,515,986
Accumulated earnings		273,465,291
NET ASSETS	$	14,895,981,277
NET ASSET VALUE
Institutional— Based on net assets of $6,535,538,243 and 546,834,579 shares outstanding, 1 billion shares authorized, $0.10 par value	$	11.95
Service— Based on net assets of $120,243,085 and 10,059,169 shares outstanding, 50 million shares authorized, $0.10 par value	$	11.95
Investor A— Based on net assets of $1,840,587,059 and 153,941,492 shares outstanding, 450 million shares authorized, $0.10 par value	$	11.96
Investor A1— Based on net assets of $28,769,024 and 2,407,970 shares outstanding, 50 million shares authorized, $0.10 par value	$	11.95
Investor C— Based on net assets of $209,532,471 and 17,538,448 shares outstanding, 100 million shares authorized, $0.10 par value	$	11.95
Investor C1— Based on net assets of $2,832,738 and 236,990 shares outstanding, 100 million shares authorized, $0.10 par value	$	11.95
Investor C2— Based on net assets of $698,681 and 58,495 shares outstanding, 50 million shares authorized, $0.10 par value	$	11.94
Class K— Based on net assets of $6,015,061,608 and 503,356,883 shares outstanding, 1 billion shares authorized, $0.10 par value	$	11.95
Class R— Based on net assets of $142,718,368 and 11,935,578 shares outstanding, 250 million shares authorized, $0.10 par value	$	11.96

See notes to financial statements.

FUND FINANCIAL STATEMENTS 9

Statement of Operations

Year Ended September 30, 2019

	BlackRock Total Return Fund
INVESTMENT INCOME
Net investment income allocated from the Master Portfolio:
Interest — unaffiliated	$	475,444,921
Dividends — affiliated		15,932,772
Dividends — unaffiliated		327,439
Securities lending income — affiliated — net		86,914
Foreign taxes withheld		(319,573	)
Total expenses		(9,277,071	)
Fees waived		434,642
Total investment income		482,630,044
FUND EXPENSES
Investment advisory		37,917,839
Transfer agent — class specific		10,000,909
Service and distribution — class specific		7,510,422
Registration		661,095
Board realignment and consolidation		116,949
Printing		115,473
Professional		96,869
Officer		17,771
Accounting services		6,797
Miscellaneous		14,687
Total expenses		56,458,811
Less transfer agent fees waived and/or reimbursed — class specific		(2,215,399	)
Total expenses after fees waived and/or reimbursed		54,243,412
Net investment income		428,386,632
REALIZED AND UNREALIZED GAIN (LOSS) ALLOCATED FROM THE MASTER PORTFOLIO
Net realized gain from investments, foreign currency transactions, forward foreign currency exchange contracts, futures contracts, options written and swaps		218,652,965
Net change in unrealized appreciation (depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts, futures contracts, options written, swaps and unfunded floating rate loan interests		624,071,217
Net realized and unrealized gain		842,724,182
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	1,271,110,814

See notes to financial statements.

10 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Statement of Changes in Net Assets

	BlackRock Total Return Fund
	Year Ended September 30,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	428,386,632		$	389,644,002
Net realized gain (loss)		218,652,965			(202,759,976	)
Net change in unrealized appreciation (depreciation)		624,071,217			(375,574,324	)
Net increase (decrease) in net assets resulting from operations		1,271,110,814			(188,690,298	)
DISTRIBUTIONS TO SHAREHOLDERS(a)(b)
Institutional		(187,713,642	)		(171,990,481	)
Service		(3,358,018	)		(3,638,411	)
Investor A		(51,952,065	)		(57,025,339	)
Investor A1		(951,501	)		(983,351	)
Investor B		—			(8,143	)
Investor C		(5,071,504	)		(6,532,847	)
Investor C1		(123,069	)		(306,956	)
Investor C2		(19,709	)		(29,093	)
Class K		(177,543,510	)		(145,324,812	)
Class R		(3,950,278	)		(4,454,410	)
Decrease in net assets resulting from distributions to shareholders		(430,683,296	)		(390,293,843	)
CAPITAL SHARE TRANSACTIONS
Net increase in net assets derived from capital share transactions		1,648,881,289			1,903,361,114
NET ASSETS(b)
Total increase in net assets		2,489,308,807			1,324,376,973
Beginning of year		12,406,672,470			11,082,295,497
End of year	$	14,895,981,277		$	12,406,672,470

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

^(b)  Prior year distribution character information and distributions in excess of net investment income has been modified or removed to conform with current year Regulation S-X presentation changes. Refer to Note 8 for this prior year information.

See notes to financial statements.

FUND FINANCIAL STATEMENTS 11

Financial Highlights

(For a share outstanding throughout each period)

	BlackRock Total Return Fund
	Institutional
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.21		$	11.77		$	11.96		$	11.71		$	11.76
Net investment income(a)			0.38			0.38			0.34			0.31			0.32
Net realized and unrealized gain (loss)			0.75			(0.56	)		(0.18	)		0.32			0.01
Net increase (decrease) from investment operations			1.13			(0.18	)		0.16			0.63			0.33
Distributions from net investment income(b)			(0.39	)		(0.38	)		(0.35	)		(0.38	)		(0.38	)
Net asset value, end of year		$	11.95		$	11.21		$	11.77		$	11.96		$	11.71
Total Return(c)
Based on net asset value			10.23	%		(1.55	)%(d)		1.43	%		5.47	%		2.77	%
Ratios to Average Net Assets
Total expenses(e)			0.47	%(f)		0.75	%(g)		0.74	%(g)		0.61	%(g)		0.56	%(g)
Total expenses after fees waived and/or reimbursed(e)			0.44	%(f)		0.71	%(g)		0.69	%(g)		0.58	%(g)		0.50	%(g)
Total expenses after fees waived and/or reimbursed excluding interest expense(e)			0.44	%(f)		0.45	%(g)		0.45	%(g)		0.45	%(g)		0.45	%(g)
Net investment income(e)			3.33	%(f)		3.31	%(g)		2.93	%(g)		2.63	%(g)		2.72	%(g)
Supplemental Data
Net assets, end of year (000)		$	6,535,538		$	5,402,121		$	4,621,641		$	3,126,440		$	1,547,791
Portfolio turnover rate of the Master Portfolio(h)			574	%		734	%		806	%		841	%		1,015	%

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

^(e)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

		Year Ended September 30,
	2019				2018			2017			2016			2015
Investments in underlying funds			0.01	%		0.01	%		0.01	%		0.01	%		—

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

^(g)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(h)  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:

		Year Ended September 30,
	2019				2018			2017			2016			2015
Portfolio turnover rate (excluding mortgage dollar roll transactions)			241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

12 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Service
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.22		$	11.77		$	11.96		$	11.71		$	11.76
Net investment income(a)			0.35			0.34			0.31			0.28			0.29
Net realized and unrealized gain (loss)			0.73			(0.54	)		(0.18	)		0.31			0.01
Net increase (decrease) from investment operations			1.08			(0.20	)		0.13			0.59			0.30
Distributions from net investment income(b)			(0.35	)		(0.35	)		(0.32	)		(0.34	)		(0.35	)
Net asset value, end of year		$	11.95		$	11.22		$	11.77		$	11.96		$	11.71
Total Return(c)
Based on net asset value			9.80	%		(1.76	)%(d)		1.13	%		5.15	%		2.55	%
Ratios to Average Net Assets
Total expenses(e)			0.74	%(f)		1.03	%(g)		1.02	%(g)		0.93	%(g)		0.80	%(g)
Total expenses after fees waived and/or reimbursed(e)			0.74	%(f)		1.03	%(g)		1.00	%(g)		0.88	%(g)		0.74	%(g)
Total expenses after fees waived and/or reimbursed excluding interest expense(e)			0.74	%(f)		0.75	%(g)		0.75	%(g)		0.75	%(g)		0.67	%(g)
Net investment income(e)			3.04	%(f)		3.01	%(g)		2.62	%(g)		2.35	%(g)		2.46	%(g)
Supplemental Data
Net assets, end of year (000)		$	120,243		$	117,278		$	125,903		$	74,723		$	45,616
Portfolio turnover rate of the Master Portfolio(h)			574	%		734	%		806	%		841	%		1,015	%

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

^(e)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

	Year Ended September 30,
	2019		2018			2017			2016			2015
Investments in underlying funds		0.01%		0.01	%		0.01	%		0.01	%		—

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

^(g)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(h)  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:

	Year Ended September 30,
	2019			2018			2017			2016			2015
Portfolio turnover rate (excluding mortgage dollar roll transactions)		241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

FUND FINANCIAL HIGHLIGHTS 13

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Investor A
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.22		$	11.78		$	11.96		$	11.71		$	11.76
Net investment income(a)			0.34			0.34			0.30			0.28			0.28
Net realized and unrealized gain (loss)			0.75			(0.56	)		(0.16	)		0.31			0.01
Net increase (decrease) from investment operations			1.09			(0.22	)		0.14			0.59			0.29
Distributions from net investment income(b)			(0.35	)		(0.34	)		(0.32	)		(0.34	)		(0.34	)
Net asset value, end of year		$	11.96		$	11.22		$	11.78		$	11.96		$	11.71
Total Return(c)
Based on net asset value			9.85	%		(1.88	)%(d)		1.18	%		5.12	%		2.44	%
Ratios to Average Net Assets
Total expenses(e)			0.79	%(f)		1.08	%(g)		1.04	%(g)		0.91	%(g)		0.87	%(g)
Total expenses after fees waived and/or reimbursed(e)			0.78	%(f)		1.07	%(g)		1.03	%(g)		0.91	%(g)		0.84	%(g)
Total expenses after fees waived and/or reimbursed excluding interest expense(e)			0.78	%(f)		0.79	%(g)		0.79	%(g)		0.78	%(g)		0.78	%(g)
Net investment income(e)			3.00	%(f)		2.97	%(g)		2.58	%(g)		2.34	%(g)		2.40	%(g)
Supplemental Data
Net assets, end of year (000)		$	1,840,587		$	1,729,459		$	2,033,975		$	2,087,043		$	2,267,386
Portfolio turnover rate of the Master Portfolio(h)			574	%		734	%		806	%		841	%		1,015	%

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

^(e)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

		Year Ended September 30,
	2019				2018			2017			2016			2015
Investments in underlying funds			0.01	%		0.01	%		0.01	%		0.01	%		—

^(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

^(g)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

^(h)  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:

		Year Ended September 30,
	2019				2018			2017			2016			2015
Portfolio turnover rate (excluding mortgage dollar roll transactions)			241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

14 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Investor A1
	Year Ended September 30,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.21		$	11.77		$	11.95		$	11.70		$	11.75
Net investment income(a)		0.37			0.36			0.32			0.30			0.31
Net realized and unrealized gain (loss)		0.74			(0.56	)		(0.16	)		0.31			0.00	(b)
Net increase (decrease) from investment operations		1.11			(0.20	)		0.16			0.61			0.31
Distributions from net investment income(c)		(0.37	)		(0.36	)		(0.34	)		(0.36	)		(0.36	)
Net asset value, end of year	$	11.95		$	11.21		$	11.77		$	11.95		$	11.70
Total Return(d)
Based on net asset value		10.06	%		(1.69	)%(e)		1.37	%		5.32	%		2.63	%
Ratios to Average Net Assets(f)(g)
Total expenses(h)		0.63	%		0.92	%		0.86	%		0.74	%		0.67	%
Total expenses after fees waived and/or reimbursed(h)		0.59	%		0.88	%		0.84	%		0.72	%		0.64	%
Total expenses after fees waived and/or reimbursed excluding interest expense(h)		0.59	%		0.60	%		0.60	%		0.60	%		0.60	%
Net investment income(h)		3.20	%		3.17	%		2.77	%		2.54	%		2.59	%
Supplemental Data
Net assets, end of year (000)	$	��  28,769		$	28,072		$	31,705		$	34,722		$	38,412
Portfolio turnover rate of the Master Portfolio(i)		574	%		734	%		806	%		841	%		1,015	%

^(a)  Based on average shares outstanding.

^(b)  Amount is less than $0.005 per share.

^(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 a 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 fees waived of less than 0.01%.

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

^(h)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

			Year Ended September 30,
		2019				2018			2017			2016			2015
	Investments in underlying funds			0.01	%		0.01	%		0.01	%		0.01	%		—
(i)  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:
			Year Ended September 30,
		2019				2018			2017			2016			2015
	Portfolio turnover rate (excluding mortgage dollar roll transactions)			241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

FUND FINANCIAL HIGHLIGHTS 15

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Investor C
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.21		$	11.77		$	11.95		$	11.70		$	11.75
Net investment income(a)			0.27			0.27			0.22			0.20			0.20
Net realized and unrealized gain (loss)			0.74			(0.56	)		(0.16	)		0.31			0.01
Net increase (decrease) from investment operations			1.01			(0.29	)		0.06			0.51			0.21
Distributions from net investment income(b)			(0.27	)		(0.27	)		(0.24	)		(0.26	)		(0.26	)
Net asset value, end of year		$	11.95		$	11.21		$	11.77		$	11.95		$	11.70
Total Return(c)
Based on net asset value			9.14	%		(2.53	)%(d)		0.52	%		4.42	%		1.76	%
Ratios to Average Net Assets
Total expenses(e)			1.51	%(f)		1.82	%(g)		1.76	%(g)		1.66	%(g)		1.60	%(g)
Total expenses after fees waived and/or reimbursed(e)			1.44	%(f)		1.74	%(g)		1.68	%(g)		1.58	%(g)		1.50	%(g)
Total expenses after fees waived and/or reimbursed excluding interest expense(e)			1.44	%(f)		1.45	%(g)		1.45	%(g)		1.45	%(g)		1.45	%(g)
Net investment income(e)			2.35	%(f)		2.32	%(g)		1.90	%(g)		1.67	%(g)		1.73	%(g)
Supplemental Data
Net assets, end of year (000)		$	209,532		$	235,682		$	339,329		$	498,254		$	421,097
Portfolio turnover rate of the Master Portfolio(h)			574	%		734	%		806	%		841	%		1,015	%

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

^(e)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

		Year Ended September 30,
		2019			2018			2017			2016			2015
	Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		—
(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%. (g) Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%. (h) Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:
		Year Ended September 30,
		2019			2018			2017			2016			2015
	Portfolio turnover rate (excluding mortgage dollar roll transactions)		241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

16 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Investor C1
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.22		$	11.77		$	11.96		$	11.71		$	11.76
Net investment income(a)			0.28			0.28			0.23			0.21			0.22
Net realized and unrealized gain (loss)			0.74			(0.55	)		(0.17	)		0.31			0.00	(b)
Net increase (decrease) from investment operations			1.02			(0.27	)		0.06			0.52			0.22
Distributions from net investment income(c)			(0.29	)		(0.28	)		(0.25	)		(0.27	)		(0.27	)
Net asset value, end of year		$	11.95		$	11.22		$	11.77		$	11.96		$	11.71
Total Return(d)
Based on net asset value			9.18	%		(2.36	)%(e)		0.52	%		4.52	%		1.85	%
Ratios to Average Net Assets(f)(g)
Total expenses(h)			1.38	%		1.69	%		1.58	%		1.49	%		1.44	%
Total expenses after fees waived and/or reimbursed(h)			1.32	%		1.66	%		1.57	%		1.48	%		1.41	%
Total expenses after fees waived and/or reimbursed excluding interest expense(h)			1.32	%		1.36	%		1.37	%		1.36	%		1.37	%
Net investment income(h)			2.48	%		2.40	%		1.93	%		1.79	%		1.83	%
Supplemental Data
Net assets, end of year (000)		$	2,833		$	10,789		$	15,744		$	69,583		$	88,551
Portfolio turnover rate of the Master Portfolio(i)			574	%		734	%		806	%		841	%		1,015	%

^(a)  Based on average shares outstanding.

^(b)  Amount is less than $0.005 per share.

^(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 a 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 fees waived of less than 0.01%.

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

^(h)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

		Year Ended September 30,
		2019			2018			2017			2016			2015
	Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		—
(i)  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:
		Year Ended September 30,
		2019			2018			2017			2016			2015
	Portfolio turnover rate (excluding mortgage dollar roll transactions)		241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

FUND FINANCIAL HIGHLIGHTS 17

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Investor C2
	Year Ended September 30,
	2019			2018			2017			2016			2015
Net asset value, beginning of year	$	11.21		$	11.76		$	11.95		$	11.70		$	11.75
Net investment income(a)		0.31			0.31			0.26			0.25			0.25
Net realized and unrealized gain (loss)		0.74			(0.55	)		(0.16	)		0.31			0.01
Net increase (decrease) from investment operations		1.05			(0.24	)		0.10			0.56			0.26
Distributions from net investment income(b)		(0.32	)		(0.31	)		(0.29	)		(0.31	)		(0.31	)
Net asset value, end of year	$	11.94		$	11.21		$	11.76		$	11.95		$	11.70
Total Return(c)
Based on net asset value		9.49	%		(2.05	)%(d)		0.84	%		4.86	%		2.17	%
Ratios to Average Net Assets
Total expenses(e)		1.30	%(f)		1.52	%(g)		1.30	%(g)		1.20	%(g)		1.16	%(g)
Total expenses after fees waived and/or reimbursed(e)		1.03	%(f)		1.32	%(g)		1.25	%(g)		1.16	%(g)		1.09	%(g)
Total expenses after fees waived and/or reimbursed excluding interest expense(e)		1.03	%(f)		1.04	%(g)		1.04	%(g)		1.04	%(g)		1.05	%(g)
Net investment income(e)		2.75	%(f)		2.72	%(g)		2.27	%(g)		2.11	%(g)		2.15	%(g)
Supplemental Data
Net assets, end of year (000)	$	699		$	1,021		$	1,259		$	3,878		$	4,729
Portfolio turnover rate of the Master Portfolio(h)		574	%		734	%		806	%		841	%		1,015	%

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

^(e)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

			Year Ended September 30,
		2019				2018			2017			2016			2015
	Investments in underlying funds			0.01	%		0.01	%		0.01	%		0.01	%		—
(f)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%. (g) Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%. (h) Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:

		Year Ended September 30,
	2019				2018			2017			2016			2015
Portfolio turnover rate (excluding mortgage dollar roll transactions)			241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

18 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Class K
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.21		$	11.77		$	11.95		$	11.71		$	11.76
Net investment income(a)			0.39			0.39			0.35			0.32			0.33
Net realized and unrealized gain (loss)			0.74			(0.56	)		(0.17	)		0.30			0.00	(b)
Net increase (decrease) from investment operations			1.13			(0.17	)		0.18			0.62			0.33
Distributions from net investment income(c)			(0.39	)		(0.39	)		(0.36	)		(0.38	)		(0.38	)
Net asset value, end of year		$	11.95		$	11.21		$	11.77		$	11.95		$	11.71
Total Return(d)
Based on net asset value			10.30	%		(1.49	)%(e)		1.59	%		5.44	%		2.84	%
Ratios to Average Net Assets
Total expenses(f)			0.37	%(g)		0.64	%(h)		0.64	%(h)		0.52	%(h)		0.46	%(h)
Total expenses after fees waived and/or reimbursed(f)			0.37	%(g)		0.64	%(h)		0.63	%(h)		0.52	%(h)		0.44	%(h)
Total expenses after fees waived and/or reimbursed excluding interest expense(f)			0.37	%(g)		0.38	%(h)		0.39	%(h)		0.39	%(h)		0.39	%(h)
Net investment income(f)			3.40	%(g)		3.36	%(h)		3.00	%(h)		2.73	%(h)		2.76	%(h)
Supplemental Data
Net assets, end of year (000)		$	6,015,062		$	4,726,240		$	3,751,146		$	2,770,095		$	2,500,152
Portfolio turnover rate of the Master Portfolio(i)			574	%		734	%		806	%		841	%		1,015	%

^(a)  Based on average shares outstanding.

^(b)  Amount is less than $0.005 per share.

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

^(f)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

	Year Ended September 30,
	2019			2018			2017			2016			2015
Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		—

^(g)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of 0.01%.

^(h)  Includes the Fund’s share of the Master Portfolio’s allocated fees waived of less than 0.01%.

⁽ⁱ⁾  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:

	Year Ended September 30,
	2019			2018			2017			2016			2015
Portfolio turnover rate (excluding mortgage dollar roll transactions)		241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

FUND FINANCIAL HIGHLIGHTS 19

Financial Highlights  (continued)

(For a share outstanding throughout each period)

	BlackRock Total Return Fund (continued)
	Class R
	Year Ended September 30,
		2019			2018			2017			2016			2015
Net asset value, beginning of year		$	11.22		$	11.78		$	11.96		$	11.71		$	11.76
Net investment income(a)			0.32			0.31			0.28			0.24			0.26
Net realized and unrealized gain (loss)			0.74			(0.56	)		(0.17	)		0.32			0.00	(b)
Net increase (decrease) from investment operations			1.06			(0.25	)		0.11			0.56			0.26
Distributions from net investment income(c)			(0.32	)		(0.31	)		(0.29	)		(0.31	)		(0.31	)
Net asset value, end of year		$	11.96		$	11.22		$	11.78		$	11.96		$	11.71
Total Return(d)
Based on net asset value			9.58	%		(2.12	)%(e)		0.93	%		4.86	%		2.18	%
Ratios to Average Net Assets(f)(g)
Total expenses(h)			1.07	%		1.37	%		1.34	%		1.22	%		1.14	%
Total expenses after fees waived and/or reimbursed(h)			1.03	%		1.31	%		1.29	%		1.17	%		1.08	%
Total expenses after fees waived and/or reimbursed excluding interest expense(h)			1.03	%		1.04	%		1.04	%		1.04	%		1.03	%
Net investment income(h)			2.76	%		2.72	%		2.36	%		2.06	%		2.15	%
Supplemental Data
Net assets, end of year (000)		$	142,718		$	156,009		$	160,166		$	90,332		$	53,622
Portfolio turnover rate of the Master Portfolio(i)			574	%		734	%		806	%		841	%		1,015	%

^(a)  Based on average shares outstanding.

^(b)  Amount is less than $0.005 per share.

^(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 a 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 fees waived of less than 0.01%.

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

^(h)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

	Year Ended September 30,
	2019			2018			2017			2016			2015
Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		—

⁽ⁱ⁾  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:

	Year Ended September 30,
	2019			2018			2017			2016			2015
Portfolio turnover rate (excluding mortgage dollar roll transactions)		241	%		350	%		540	%		598	%		725	%

See notes to financial statements.

20 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements BlackRock Total Return Fund

1. ORGANIZATION

BlackRock Total Return Fund (the “Fund”), a series of BlackRock Bond Fund, Inc. (the “Corporation”), is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as an open-end management investment company. The Fund is classified as diversified. The Fund seeks to achieve its investment objective by investing all of its assets in Master Total Return Portfolio (the “Master Portfolio”) of Master Bond LLC, an affiliate of the Fund, which has the same investment objective and strategies as the Fund. The Corporation is organized as a Maryland corporation. The Master Bond LLC is organized as a Delaware limited liability company. 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 September 30, 2019, the percentage of the Master Portfolio owned by the Fund was 94.9%. The consolidated 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, Service and Class K Shares are sold without a sales charge and only to certain eligible investors. Investor A Shares are generally sold with an initial sales charge, and 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. Investor A1 Shares are subject to a maximum sales charge on purchases of 1.00%. The sales charge does not apply to dividend and capital gain reinvestments by existing shareholders and new purchases for certain employer-sponsored retirement plans, which are currently the only investors who may invest in Investor A1 Shares. Investor C Shares may be subject to a 1.00% CDSC if redeemed within one year of purchase. However, the CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through the reinvestment of dividends and capital gains by existing shareholders. Class R Shares are sold without a sales charge and only to certain employer-sponsored retirement plans. Service, Investor A, Investor A1, Investor C, Investor C1, Investor C2 and Class R Shares bear certain expenses related to shareholder servicing of such shares, and Investor C, Investor C1, Investor C2 and Class R Shares also bear certain expenses related to the distribution of such shares. Investor A and Investor C Shares are generally available through financial intermediaries. Investor A1, Investor C1 and Investor C2 Shares are only available for dividend and capital gain reinvestment by existing shareholders, and for purchase by certain employer-sponsored retirement plans. Effective November 8, 2018, the Fund adopted an automatic conversion feature whereby Investor C, Investor C1 and Investor C2 Shares held for approximately ten years will be automatically converted into Investor A Shares. Each class has exclusive voting rights with respect to matters relating to its shareholder servicing and distribution expenditures (except that Investor C, Investor C1 and Investor C2 shareholders may vote on material changes to the Investor A Shares distribution and service plan). The Board of Directors of the Corporation and Board of Directors of the Master Bond LLC are referred to throughout this report as the “Board of Directors” or the “Board” and the members are referred to as “Directors”.

Share Class	Initial Sales Charge		CDSC		Conversion Privilege
Institutional, Service, Class K and Class R Shares	No		No		None
Investor A Shares	Yes		No	(a)	None
Investor A1 Shares	No	(b)	No	(c)	None
Investor C Shares	No		Yes		To Investor A Shares after approximately 10 years
Investor C1 and Investor C2 Shares	No		No	(d)	To Investor A Shares after approximately 10 years

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

^(b)  Investor A1 Shares are subject to a maximum sales charge on purchases of 1.00%. The sales charge does not apply to dividend and capital gain reinvestments by existing shareholders and new purchases for certain employer-sponsored retirement plans, which are currently the only investors who may invest in Investor A1 Shares.

^(c)  Investor A1 Shares may be subject to a CDSC for certain redemptions where no initial sales charge was paid at the time of purchase. However, the CDSC does not apply to redemptions by certain employer-sponsored retirement plans, or to redemptions of shares acquired through reinvestment of dividends and capital gains by existing shareholders.

^(d)  A CDSC of 1.00% is assessed on certain redemptions of Investor C1 and Investor C2 Shares made within one year of after purchase. The CDSC does not apply to redemptions by certain employer-sponsored retirement plans or to redemptions of shares acquired through reinvestment of dividends and capital gains by existing shareholders.

The Fund, together with certain other registered investment companies advised by BlackRockAdvisors, LLC (the “Manager”) or its affiliates, is included in a complex of non-index fixed-income mutual funds and all BlackRock-advised closed-end funds referred to as the BlackRock Fixed-Income 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 the ex-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.

Net income and realized gains from investments held by the Master Portfolio’s investment in BlackRock Cayman Master Total Return Portfolio I, Ltd. (the “Subsidiary”) are treated as ordinary income for tax purposes. If a net loss is realized by the Subsidiary in any taxable year, the loss will generally not be available to offset the Fund’s ordinary income and/or capital gains for that year. Effective November 30, 2018, the Fund, through the Master Portfolio, no longer invests in the Subsidiary.

Deferred Compensation Plan:Under the Deferred Compensation Plan (the “Plan”) approved by the Corporation’s Board effective January 1, 2019, the directors who are

FUND NOTESTO FINANCIAL STATEMENTS 21

Notes to Financial Statements  (continued) BlackRock Total Return Fund

not “interested persons” of the Fund, as defined in the 1940 Act (“Independent Directors”), may defer a portion of their annual complex-wide compensation. Deferred amounts earn an approximate return as though equivalent dollar amounts had been invested in common shares of certain funds in the BlackRock Fixed-Income Complex selected by the Independent Directors. This has the same economic effect for the Independent Directors as if the Independent Directors had invested the deferred amounts directly in certain funds in the BlackRock Fixed-Income Complex.

The Plan is not funded and obligations thereunder represent general unsecured claims against the general assets of the Fund, as applicable. Deferred compensation liabilities are included in the Directors’ and Officer’s fees payable in the Statement of Assets and Liabilities and will remain as a liability of the Fund until such amounts are distributed in accordance with the Plan.

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.

The Fund has an arrangement with its custodian whereby credits are earned on uninvested cash balances, which could be used to reduce custody fees and/or overdraft charges. The Fund may incur charges on certain uninvested cash balances and overdrafts, subject to certain conditions.

3. INVESTMENT VALUATION AND FAIR VALUE MEASUREMENTS

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 Consolidated Financial Statements, which are included elsewhere in this report.

4. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

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

For such services, the Fund pays the Manager a monthly fee at an annual rate equal to the following percentages of the average daily value of the Fund’s net assets:

Average Daily Net Assets	Investment Advisory Fee(a)
First $250 million	0.32	%
$250 million — $500 million.	0.31
$500 million — $750 million.	0.30
Greater than $750 million	0.29

^(a)  This investment advisory fee applies to the Fund for as long as the Fund invests in the Master Portfolio or another master fund advised by the Manager or an affiliate thereof in a master-feeder structure. If the Fund ceases to operate as a feeder fund in a master/feeder structure, the maximum actual investment advisory fees payable to the Manager (as a percentage of average daily net assets) by the Fund are as follows: 0.48% (first $250 million), 0.43% ($250 million — $500 million), 0.38% ($500 million — $750 million) and 0.34% (greater than $750 million).

With respect to the Fund, the Manager entered into separate sub-advisory agreements with BlackRock International Limited (“BIL”) and BlackRock (Singapore) Limited (“BRS”), each an affiliate of the Manager. The Manager pays BIL and BRS for services they provide for that portion of the Fund for which BIL and BRS, as applicable, act as sub-advisers, a monthly fee that is equal to a percentage of the investment advisory fees paid by the Fund to the Manager.

Service and Distribution Fees:The Corporation, 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 Manager. Pursuant to the Distribution and Service Plan and in accordance with Rule 12b-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 Fee		Distribution Fee
Service	0.25	%	—	%
Investor A	0.25		—
Investor A1	0.10		—
Investor C	0.25		0.75
Investor C1	0.25		0.55
Investor C2	0.25		0.25
Class R	0.25		0.25

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

22 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued) BlackRock Total Return Fund

For the year ended September 30, 2019, the following table shows the class specific service and distribution fees borne directly by each share class of the Fund:

Service	$	275,770
Investor A		4,308,404
Investor A1		29,533
Investor C		2,139,885
Investor C1		37,552
Investor C2		3,510
Class R		715,768
	$	7,510,422

Transfer Agent:Pursuant to written agreements, certain financial intermediaries, some of which may be affiliates, provide the Fund with sub-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 September 30, 2019, the Fund paid the following amounts to affiliates of BlackRock in return for these services, which are included in transfer agent — class specific in the Statement of Operations:

Institutional	$	898,933
Service		5,980
Investor C		30

The Manager 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 September 30, 2019, the Fund reimbursed the Manager 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	$	23,661
Service		580
Investor A		11,220
Investor A1		125
Investor C		2,281
Investor C1		30
Investor C2		9
Class K		10,610
Class R		1,225

For the year ended September 30, 2019, the following table shows the class specific transfer agent fees borne directly by each share class of the Fund:

Institutional	$	5,916,320
Service		136,013
Investor A		3,024,775
Investor A1		46,912
Investor C		309,962
Investor C1		12,506
Investor C2		3,182
Class K		267,711
Class R		283,528
	$	10,000,909

Other Fees:For the year ended September 30, 2019, affiliates earned underwriting discounts, direct commissions and dealer concessions on sales of the Fund’s Investor A Shares which totaled $52,811.

For the year ended September 30, 2019, affiliates received CDSCs as follows:

Investor A	$	28,274
Investor C		1

Expense Limitations, Waivers and Reimbursements:With the exception of the Fund’s investment in the Master Portfolio, the Manager contractually agreed to waive its investment advisory fee with respect to any portion of the Fund’s assets invested in affiliated equity and fixed-income mutual funds and affiliated exchange-traded funds that have a contractual management fee through January 31, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Directors, or by a vote of a majority of the outstanding voting securities of the Fund. For the year ended September 30, 2019, there were no fees waived and/or reimbursed by the Manager pursuant to this arrangement.

FUND NOTESTO FINANCIAL STATEMENTS 23

Notes to Financial Statements  (continued) BlackRock Total Return Fund

With respect to the Fund, the 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	0.44	%
Service	0.75
Investor A	0.78
Investor A1	0.59
Investor C	1.44
Investor C1	1.36
Investor C2	1.03
Class K	0.39
Class R	1.03

The Manager has agreed not to reduce or discontinue this contractual expense limitation through January 31, 2020, unless approved by the Board, including a majority of the Independent Directors, or by a vote of a majority of the outstanding voting securities of the Fund. For the year ended September 30, 2019, there were no fees waived and/or reimbursed by the Manager.

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 September 30, 2019, class specific waivers and/or reimbursements are as follows:

	Institutional	Service	Investor A	Investor A1	Investor C	Investor C1	Investor C2	Class R	Total
Transfer agent fees waived and/or reimbursed — class specific	$1,776,313	$274	$218,467	$10,433	$151,590	$2,629	$1,950	$53,743	$2,215,399

Directors and Officers:Certain directors and/or officers of the Corporation are directors and/or officers of BlackRock or its affiliates. The Fund reimburses the Manager for a portion of the compensation paid to the Corporation’s Chief Compliance Officer, which is included in Officer in the 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 September 30, 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 September 30, 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.

U.S. GAAP requires that certain components of net assets be adjusted to reflect permanent differences between financial and tax reporting. These reclassifications have no effect on net assets or net asset values per share. As of period end, the following permanent differences attributable to the timing and recognition of partnership income were reclassified to the following accounts:

Paid-in capital	$	(50,877	)
Accumulated earnings		50,877

The tax character of distributions paid was as follows:

	09/30/19	09/30/18
Ordinary income	$430,683,296	$390,293,843

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

Non-expiring capital loss carryforward(a)	$	(61,799,267	)
Net unrealized gains(b)		335,264,558
	$	273,465,291

^(a)  Amounts available to offset future realized capital gains.

^(b)  The difference between book-basis and tax-basis net unrealized gains was attributable primarily to the timing and recognition of partnership income.

During the year ended September 30, 2019, the Fund utilized $264,537,543 of its capital loss carryforward.

24 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Financial Statements  (continued) BlackRock Total Return Fund

6. CAPITAL SHARE TRANSACTIONS

Transactions in capital shares for each class were as follows:

	Year Ended 09/30/19						Year Ended 09/30/18
	Shares			Amount			Shares			Amount
Institutional
Shares sold		248,575,631		$	2,861,599,396			272,466,653		$	3,128,810,897
Shares issued to shareholders in reinvestment of distributions		14,525,913			167,432,098			13,238,372			151,563,700
Shares redeemed		(197,982,082	)		(2,255,643,059	)		(196,586,431	)		(2,245,389,758	)
Net increase		65,119,462		$	773,388,435			89,118,594		$	1,034,984,839
Service
Shares sold		2,633,011		$	30,539,897			2,650,586		$	30,473,553
Shares issued to shareholders in reinvestment of distributions		290,731			3,346,732			316,986			3,632,627
Shares redeemed		(3,320,538	)		(37,717,924	)		(3,205,100	)		(36,834,782	)
Net decrease		(396,796	)	$	(3,831,295	)		(237,528	)	$	(2,728,602	)
Investor A
Shares issued from conversion(a)		—		$	—			105,284		$	1,231,828
Shares sold and automatic conversion of shares		52,838,741			608,058,533			42,356,774			487,400,424
Shares issued to shareholders in reinvestment of distributions		4,315,535			49,716,759			4,757,468			54,552,537
Shares redeemed		(57,369,066	)		(655,450,031	)		(65,778,983	)		(755,244,044	)
Net increase (decrease)		(214,790	)	$	2,325,261			(18,559,457	)	$	(212,059,255	)
Investor A1
Shares sold		728,073		$	8,251,242			548,999		$	6,338,595
Shares issued to shareholders in reinvestment of distributions		71,592			823,903			73,578			842,998
Shares redeemed		(895,767	)		(10,300,632	)		(812,818	)		(9,290,628	)
Net decrease		(96,102	)	$	(1,225,487	)		(190,241	)	$	(2,109,035	)
Investor B
Shares sold		—		$	—			60		$	1,060
Shares issued to shareholders in reinvestment of distributions		—			—			448			5,239
Shares converted(a)		—			—			(105,375	)		(1,231,828	)
Shares redeemed and automatic conversion of shares		—			—			(16,575	)		(194,092	)
Net decrease		—		$	—			(121,442	)	$	(1,419,621	)
Investor C
Shares sold		2,388,212		$	27,390,322			2,045,266		$	23,585,083
Shares issued to shareholders in reinvestment of distributions		394,319			4,531,917			507,575			5,821,437
Shares redeemed and automatic conversion of shares		(6,268,068	)		(71,295,742	)		(10,365,871	)		(119,188,707	)
Net decrease		(3,485,537	)	$	(39,373,503	)		(7,813,030	)	$	(89,782,187	)
Investor C1
Shares sold		47,120		$	538,826			92,669		$	1,063,856
Shares issued to shareholders in reinvestment of distributions		10,726			122,547			26,637			305,657
Shares redeemed and automatic conversion of shares		(782,823	)		(8,816,460	)		(494,632	)		(5,698,380	)
Net decrease		(724,977	)	$	(8,155,087	)		(375,326	)	$	(4,328,867	)
Investor C2
Shares sold		15,166		$	173,976			10,335		$	118,817
Shares issued to shareholders in reinvestment of distributions		1,693			19,459			2,538			29,079
Shares redeemed and automatic conversion of shares		(49,499	)		(554,379	)		(28,727	)		(333,140	)
Net decrease		(32,640	)	$	(360,944	)		(15,854	)	$	(185,244	)

FUND NOTESTO FINANCIAL STATEMENTS 25

Notes to Financial Statements  (continued) BlackRock Total Return Fund

	Year Ended 09/30/19							Year Ended 09/30/18
		Shares			Amount			Shares			Amount
Class K
Shares sold			177,823,402		$	2,038,544,786			169,746,822		$	1,942,482,577
Shares issued to shareholders in reinvestment of distributions			14,426,091			166,439,994			11,938,438			136,576,430
Shares redeemed			(110,398,196	)		(1,256,722,089	)		(78,885,930	)		(901,866,813	)
Net increase			81,851,297		$	948,262,691			102,799,330		$	1,177,192,194
Class R
Shares sold			3,353,858		$	38,664,537			4,129,594		$	47,578,401
Shares issued to shareholders in reinvestment of distributions			341,935			3,935,434			387,445			4,440,513
Shares redeemed			(5,664,806	)		(64,748,753	)		(4,211,797	)		(48,222,022	)
Net increase (decrease)			(1,969,013	)	$	(22,148,782	)		305,242		$	3,796,892
Total Net Increase			140,050,904		$	1,648,881,289			164,910,288		$	1,903,361,114

^(a) On December 27, 2017, the Fund’s Investor B Shares converted into Investor A Shares.

7. REGULATION S-X AMENDMENTS

On August 17, 2018, the SEC adopted amendments to certain disclosure requirements in Securities Act Release No. 33-10532, Disclosure Update and Simplification. The Fund has adopted the amendments pertinent to Regulation S-X in this shareholder report. The amendments impacted certain disclosure presentation on the Statement of Assets and Liabilities, Statements of Changes in Net Assets and Notes to the Financial Statements.

Prior year distribution information and undistributed net investment income in the Statements of Changes in Net Assets has been modified to conform to the current year presentation in accordance with the Regulation S-X changes.

Distributions for the year ended September 30, 2018 were classified as follows:

Share Class	Net Investment Income
Institutional	$	171,990,481
Service		3,638,411
Investor A		57,025,339
Investor A1		983,351
Investor B		8,143
Investor C		6,532,847
Investor C1		306,956
Investor C2		29,093
Class K		145,324,812
Class R		4,454,410

Distributions in excess of net investment income as of September 30, 2018 was $(8,290,155).

8. 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.

26 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm

To the Shareholders of BlackRock Total Return Fund and the Board of Directors of BlackRock Bond Fund, Inc.:

Opinion on the Financial Statements and Financial Highlights

We have audited the accompanying statement of assets and liabilities of BlackRock Total Return Fund of Blackrock Bond Fund, Inc. (the “Fund”) as of September 30, 2019, the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended, the financial highlights for each of the five years in the period then ended, and the related notes. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of September 30, 2019, and 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 then ended, and the financial highlights for each of the five years in the period then ended in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements and financial highlights 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 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 and financial highlights are free of material misstatement, whether due to error or fraud. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Fund’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements and financial highlights, 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 and financial highlights. 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 and financial highlights. We believe that our audits provide a reasonable basis for our opinion.

Deloitte & Touche LLP

Boston, Massachusetts

November 22, 2019

We have served as the auditor of one or more BlackRock investment companies since 1992.

Important Tax Information(unaudited)

During the fiscal year ended September 30, 2019, the following information is provided with respect to the ordinary income distribution paid by the Fund:

	Months Paid
Qualified Dividend Income for Individuals(a)	January 2019 — September 2019	1.49	%
Interest-Related Dividends for Non-U.S. Residents(b)	October 2018 — December 2018	68.82
	January 2019 — September 2019	79.65
Federal Obligation Interest(c)		4.63

^(a)  The Funds hereby designate 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.

^(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.

REPORTOF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM/IMPORTANT TAX INFORMATION 27

Master Portfolio Information Master Total Return Portfolio

As of September 30, 2019

PORTFOLIO COMPOSITION

Asset Type	Percent of Total Investments(a)
U.S. Government Sponsored Agency Securities		52%
Corporate Bonds		24
Asset-Backed Securities		7
U.S. Treasury Obligations		6
Non-Agency Mortgage-Backed Securities		3
Taxable Municipal Bonds		3
Foreign Government Obligations		2
Floating Rate Loan Interests		1
Foreign Agency Obligations		1
Preferred Securities		1
Common Stocks		—	(b)
Warrants		—	(b)

^(a) Total investments exclude short-term securities, options purchased, options written and TBA sale commitments.

^(b) Amount is less than 1%.

CREDIT QUALITY ALLOCATION^(a)

Credit Rating	Percent of Total Investments(b)
AAA/Aaa		62%
AA/Aa		5
A		12
BBB/Baa		12
BB/Ba		2
B		1
CCC/Caa		1
CC/Ca		1
N/R(c)		4

^(a) 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 if ratings differ. 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.

^(b) Total investments exclude short-term securities, options purchased, options written and TBA sale commitments.

^(c) The investment adviser evaluates the credit quality of unrated investments based upon certain factors including, but not limited to, credit ratings for similar investments and financial analysis of sectors, individual investments and/or issuers. Using this approach, the investment adviser has deemed unrated U.S. Government Sponsored Agency Securities and U.S. Treasury Obligations to be of similar credit quality as investments rated AAA/Aaa.

28 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments   September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Asset-Backed Securities — 10.3%
Accredited Mortgage Loan Trust, Series 2006-1, Class M2, (1 mo. LIBOR US + 0.340%), 2.36%, 04/25/36(a)	USD		5,510	$	2,978,322
ACE Securities Corp. Home Equity Loan Trust:
Series 2003-OP1, Class A2, (1 mo. LIBOR US + 0.720%), 2.74%, 12/25/33(a)			581		571,550
Series 2006-CW1, Class A2C, (1 mo. LIBOR US + 0.140%), 2.16%, 07/25/36(a)			388		329,883
Series 2007-HE4, Class A2A, (1 mo. LIBOR US + 0.130%), 2.15%, 05/25/37(a)			2,751		760,048
ACIS CLO Ltd., Series 2014-4A, Class A, (3 mo. LIBOR US + 1.420%), 3.67%, 05/01/26(a)(b)			2,009		2,011,970
Adams Mill CLO Ltd., Series 2014-1A, Class A2R, (3 mo. LIBOR US + 1.100%), 3.40%, 07/15/26(a)(b)			3,504		3,503,609
AIMCO CLO, Series 2017-AA, Class A, (3 mo. LIBOR US + 1.260%), 3.54%, 07/20/29(a)(b)			500		500,337
Ajax Mortgage Loan Trust:
Series 2017-D, Class A, 3.75%, 12/25/57(b)			10,239		10,533,933
Series 2017-D, Class B, 0.00%, 12/25/57(b)(c)(d)			1,765		794,161
Series 2018-A, Class A, 3.85%, 04/25/58(b)(c)			10,151		9,990,023
Series 2018-A, Class B, 0.00%, 04/25/58(b)(c)(d)			2,680		1,554,265
Series 2018-B, Class A, 3.75%, 02/26/57(b)(c)			5,940		5,936,898
Series 2018-B, Class B, 0.00%, 02/26/57(b)(c)			3,134		877,404
Series 2018-D, Class A, 3.75%, 08/25/58(b)(c)(d)			11,276		11,318,688
Series 2018-D, Class B, 0.00%, 08/25/58(b)(c)(d)			2,855		1,598,609
Series 2018-E, Class A, 4.38%, 06/25/58(b)(d)			4,830		4,882,113
Series 2018-E, Class B, 5.25%, 06/25/58(b)(d)			840		874,171
Series 2018-E, Class C, 0.00%, 06/25/58(b)(c)(d)			2,157		646,550
Series 2018-F, Class A, 4.38%, 11/25/58(b)(c)(d)			16,601		16,727,421
Series 2018-F, Class B, 5.25%, 11/25/58(b)(c)(d)			2,415		2,388,827
Series 2018-F, Class C, 0.00%, 11/25/58(b)(c)			5,808		2,824,864
Series 2018-G, Class A, 4.38%, 06/25/57(b)(c)(d)			14,707		14,798,535
Series 2018-G, Class B, 5.25%, 06/25/57(b)(c)(d)			2,042		2,017,904
Series 2018-G, Class C, 0.00%, 06/25/57(b)(c)			5,273		4,992,193
Series 2019-A, Class A, 3.75%, 08/25/57(b)(d)			15,712		15,696,926
Series 2019-A, Class B, 5.25%, 08/25/57(b)(c)(d)			1,720		1,695,404
Series 2019-A, Class C, 0.00%, 08/25/57(b)			4,309		3,680,971
Series 2019-B, Class A, 3.75%, 01/25/59(b)(d)			25,984		26,032,621
Series 2019-B, Class B, 5.25%, 01/25/59(b)(d)			2,845		2,789,343

Security		Par (000)		Value
Ajax Mortgage Loan Trust: (continued)
Series 2019-B, Class C, 0.00%, 01/25/59(b)(c)	USD		7,296	$	5,996,131
Series 2019-C, Class A, 3.95%, 10/25/58(b)(c)(d)			7,312		7,370,995
Series 2019-E, Class A, 3.00%, 10/30/59(b)			27,810		27,717,571
Series 2019-E, Class B, 4.88%, 10/30/59(b)			2,600		2,584,004
Series 2019-E, Class C, 0.00%, 10/30/59(b)			6,670		3,024,719
Allegro CLO II-S Ltd., Series 2014-1RA, Class A1, (3 mo. LIBOR US + 1.080%), 3.36%, 10/21/28(a)(b)			3,790		3,782,247
Allegro CLO IV Ltd.:
Series 2016-1A, Class AR, (3 mo. LIBOR US + 1.150%), 3.45%, 01/15/30(a)(b)			6,640		6,640,000
Series 2016-1A, Class BR, (3 mo. LIBOR US + 1.700%), 4.00%, 01/15/30(a)(b)			2,530		2,530,000
Allegro CLO V Ltd., Series 2017-1A, Class A, (3 mo. LIBOR US + 1.240%), 3.56%, 10/16/30(a)(b)			1,100		1,101,006
ALM V Ltd.:
Series 2012-5A, Class A1R3, (3 mo. LIBOR US + 0.910%), 3.21%, 10/18/27(a)(b)			4,410		4,406,269
Series 2012-5A, Class A2R3, (3 mo. LIBOR US + 1.250%), 3.55%, 10/18/27(a)(b)			1,600		1,585,486
Series 2012-5A, Class BR3, (3 mo. LIBOR US + 1.650%), 3.95%, 10/18/27(a)(b)			2,140		2,107,406
ALM VI Ltd., Series 2012-6A, Class A2R3, (3 mo. LIBOR US + 1.400%), 3.70%, 07/15/26(a)(b)			1,514		1,503,348
ALM VII Ltd., Series 2012-7A, Class A1A2, (3 mo. LIBOR US + 1.170%), 3.47%, 07/15/29(a)(b)			750		750,415
ALM VII R Ltd., Series 2013-7RA, Class A1R, (3 mo. LIBOR US + 1.410%), 3.71%, 10/15/28(a)(b)			2,970		2,969,070
ALM VIII Ltd.:
Series 2013-8A, Class A1R, (3 mo. LIBOR US + 1.490%), 3.79%, 10/15/28(a)(b)			9,310		9,312,972
Series 2013-8A, Class A2R, (3 mo. LIBOR US + 1.800%), 4.10%, 10/15/28(a)(b)			600		599,204
ALM XII Ltd.:
Series 2015-12A, Class A1R2, (3 mo. LIBOR US + 0.890%), 3.21%, 04/16/27(a)(b)			1,195		1,194,426
Series 2015-12A, Class BR2, (3 mo. LIBOR US + 1.650%), 3.97%, 04/16/27(a)(b)			3,635		3,615,901
ALM XVI Ltd./ALM XVI LLC:
Series 2015-16A, Class A2R2, (3 mo. LIBOR US + 1.500%), 3.80%, 07/15/27(a)(b)			6,284		6,264,502
Series 2015-16A, Class BR2, (3 mo. LIBOR US + 1.900%), 4.20%, 07/15/27(a)(b)			2,060		2,032,516
ALM XVIII Ltd., Series 2016-18A, Class A2R, (3 mo. LIBOR US + 1.650%), 3.95%, 01/15/28(a)(b)			750		748,088
AMMC CLO 16 Ltd., Series 2015-16A, Class BR, (3 mo. LIBOR US + 1.600%), 3.90%, 04/14/29(a)(b)			500		496,581

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 29

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
AMMC CLO 19 Ltd., Series 2016-19A, Class C, (3 mo. LIBOR US + 2.800%), 5.10%, 10/15/28(a)(b)	USD		720	$	721,671
AMMC CLO 21 Ltd., Series 2017-21A, Class A, (3 mo. LIBOR US + 1.250%), 3.52%, 11/02/30(a)(b)			750		748,588
AMMC CLO XII Ltd., Series 2013-12A, Class AR, (3 mo. LIBOR US + 1.200%), 3.38%, 11/10/30(a)(b)			540		538,023
AMMC CLO XIII Ltd., Series 2013-13A, Class A1LR, (3 mo. LIBOR US + 1.260%), 3.54%, 07/24/29(a)(b)			2,620		2,628,322
AMMC CLO XIV Ltd., Series 2014-14A, Class A1LR, (3 mo. LIBOR US + 1.250%), 3.53%, 07/25/29(a)(b)			6,220		6,219,517
Anchorage Capital CLO 3-R Ltd.:
Series 2014-3RA, Class A, (3 mo. LIBOR US + 1.050%), 3.31%, 01/28/31(a)(b)			2,120		2,106,696
Series 2014-3RA, Class B, (3 mo. LIBOR US + 1.500%), 3.76%, 01/28/31(a)(b)			3,600		3,534,723
Series 2014-3RA, Class C, (3 mo. LIBOR US + 1.850%), 4.11%, 01/28/31(a)(b)			500		482,222
Anchorage Capital CLO 4-R Ltd.:
Series 2014-4RA, Class A, (3 mo. LIBOR US + 1.050%), 3.31%, 01/28/31(a)(b)			5,330		5,312,163
Series 2014-4RA, Class C, (3 mo. LIBOR US + 1.850%), 4.11%, 01/28/31(a)(b)			3,760		3,624,380
Anchorage Capital CLO 5-R Ltd.:
Series 2014-5RA, Class B, (3 mo. LIBOR US + 1.450%), 3.75%, 01/15/30(a)(b)			9,200		9,054,163
Series 2014-5RA, Class C, (3 mo. LIBOR US + 1.850%), 4.15%, 01/15/30(a)(b)			3,540		3,494,115
Anchorage Capital CLO 6 Ltd., Series 2015-6A, Class AR, (3 mo. LIBOR US + 1.270%), 3.57%, 07/15/30(a)(b)			4,010		4,007,736
Anchorage Capital CLO 7 Ltd.:
Series 2015-7A, Class B1R, (3 mo. LIBOR US + 1.300%), 3.60%, 10/15/27(a)(b)			3,470		3,445,088
Series 2015-7A, Class CR, (3 mo. LIBOR US + 1.700%), 4.00%, 10/15/27(a)(b)			2,880		2,850,165
Anchorage Capital CLO 8 Ltd.:
Series 2016-8A, Class AR, (3 mo. LIBOR US + 1.000%), 3.26%, 07/28/28(a)(b)			2,430		2,431,222
Series 2016-8A, Class BR, (3 mo. LIBOR US + 1.600%), 3.86%, 07/28/28(a)(b)			3,050		3,037,709
Anchorage Capital CLO Ltd.:
Series 2013-1A, Class A1R, (3 mo. LIBOR US + 1.250%), 3.55%, 10/13/30(a)(b)			2,755		2,749,305
Series 2013-1A, Class A2R, (3 mo. LIBOR US + 1.650%), 3.95%, 10/13/30(a)(b)			750		740,114
Series 2013-1A, Class BR, (3 mo. LIBOR US + 2.150%), 4.45%, 10/13/30(a)(b)			1,410		1,395,830
Apidos CLO XII, Series 2013-12A, Class AR, (3 mo. LIBOR US + 1.080%), 3.38%, 04/15/31(a)(b)			2,402		2,390,408
Apidos CLO XV, Series 2013-15A, Class A1RR, (3 mo. LIBOR US + 1.010%), 3.29%, 04/20/31(a)(b)			1,080		1,068,021
Apidos CLO XVI, Series 2013-16A, Class A1R, (3 mo. LIBOR US + 0.980%), 3.28%, 01/19/25(a)(b)			281		280,988
Apidos CLO XVIII, Series 2018-18A, Class A1, (3 mo. LIBOR US + 1.140%), 3.42%, 10/22/30(a)(b)			880		876,822
Apres Static CLO Ltd., Series 2019-1A, Class A2, (3 mo. LIBOR US + 1.750%), 4.05%, 01/15/27(a)(b)			350		348,954

Security		Par (000)		Value
Arbor Realty Collateralized Loan Obligation Ltd., Series 2017-FL3, Class A, (1 mo. LIBOR US + 0.990%), 3.02%, 12/15/27(a)(b)	USD		3,740	$	3,738,462
Arbor Realty Commercial Real Estate Notes Ltd., Series 2017-FL2, Class A, (1 mo. LIBOR US + 0.990%), 3.02%, 08/15/27(a)(b)			1,660		1,659,794
ARES XXXVII CLO Ltd., Series 2015-4A, Class A1R, (3 mo. LIBOR US + 1.170%), 3.47%, 10/15/30(a)(b)			1,150		1,148,553
Argent Mortgage Loan Trust, Series 2005-W1, Class A2, (1 mo. LIBOR US + 0.480%), 2.50%, 05/25/35(a)			4,078		3,765,329
ASSURANT CLO I Ltd., Series 2017-1A, Class B, (3 mo. LIBOR US + 1.700%), 3.98%, 10/20/29(a)(b)			1,400		1,395,271
Atrium IX, Series 9A, Class AR, (3 mo. LIBOR US + 1.240%), 3.38%, 05/28/30(a)(b)			4,010		4,010,018
Atrium XII:
Series 12A, Class AR, (3 mo. LIBOR US + 0.830%), 3.11%, 04/22/27(a)(b)			1,620		1,620,287
Series 12A, Class CR, (3 mo. LIBOR US + 1.650%), 3.93%, 04/22/27(a)(b)			2,381		2,357,864
Avery Point IV CLO Ltd., Series 2014-1A, Class AR, (3 mo. LIBOR US + 1.100%), 3.38%, 04/25/26(a)(b)			19,451		19,464,709
Avery Point V CLO Ltd.:
Series 2014-5A, Class AR, (3 mo. LIBOR US + 0.980%), 3.28%, 07/17/26(a)(b)			2,614		2,615,321
Series 2014-5A, Class BR, (3 mo. LIBOR US + 1.500%), 3.80%, 07/17/26(a)(b)			2,250		2,241,829
Avery Point VI CLO Ltd.:
Series 2015-6A, Class AR, (3 mo. LIBOR US + 1.050%), 3.34%, 08/05/27(a)(b)			3,960		3,964,025
Series 2015-6A, Class BR, (3 mo. LIBOR US + 1.500%), 3.79%, 08/05/27(a)(b)			3,240		3,217,965
Avery Point VII CLO Ltd., Series 2015-7A, Class AR, (3 mo. LIBOR US + 1.140%), 3.44%, 01/15/28(a)(b)			7,480		7,479,627
B2R Mortgage Trust, Series 2015-2, Class A, 3.34%, 11/15/48(b)			308		308,277
Babson CLO Ltd.:
Series 2015-2A, Class AR, (3 mo. LIBOR US + 1.190%), 3.47%, 10/20/30(a)(b)			2,590		2,581,808
Series 2015-IA, Class BR, (3 mo. LIBOR US + 1.400%), 3.68%, 01/20/31(a)(b)			610		595,432
Bain Capital Credit CLO, Series 2018-2A, Class A1, (3 mo. LIBOR US + 1.080%), 3.38%, 07/19/31(a)(b)			1,420		1,408,148
Bain Capital Credit CLO Ltd.:
Series 2016-2A, Class AR, (3 mo. LIBOR US + 1.140%), 3.26%, 01/15/29(a)(b)			1,350		1,351,470
Series 2016-2A, Class BR, (3 mo. LIBOR US + 1.800%), 3.92%, 01/15/29(a)(b)			1,000		1,000,921
BankAmerica Manufactured Housing Contract Trust:
Series 1997-2, Class B1, 7.07%, 02/10/22(d)			1,680		1,277,109
Series 1998-2, Class B1, 7.58%, 12/10/25(d)			2,790		1,625,029
Barings CLO Ltd., Series 2018-3A, Class A1, (3 mo. LIBOR US + 0.950%), 3.23%, 07/20/29(a)(b)			1,085		1,084,264
Battalion CLO VII Ltd., Series 2014-7A, Class A1RR, (3 mo. LIBOR US + 1.040%), 3.34%, 07/17/28(a)(b)			3,450		3,441,243

30 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Battalion CLO X Ltd., Series 2016-10A, Class A1R, (3 mo. LIBOR US + 1.250%), 3.53%, 01/24/29(a)(b)	USD		23,120	$	23,167,308
Bayview Financial Revolving Asset Trust:
Series 2004-B, Class A1, (1 mo. LIBOR US + 1.000%), 3.04%, 05/28/39(a)(b)			6,227		5,741,374
Series 2004-B, Class A2, (1 mo. LIBOR US + 1.300%), 3.34%, 05/28/39(a)(b)			598		504,809
Series 2005-A, Class A1, (1 mo. LIBOR US + 1.000%), 3.04%, 02/28/40(a)(b)			2,686		2,602,153
Series 2005-E, Class A1, (1 mo. LIBOR US + 1.000%), 3.04%, 12/28/40(a)(b)			1,027		1,014,169
BCMSC Trust:
Series 2000-A, Class A2, 7.58%, 06/15/30(d)			1,674		553,336
Series 2000-A, Class A3, 7.83%, 06/15/30(d)			1,554		530,854
Series 2000-A, Class A4, 8.29%, 06/15/30(d)			1,121		405,435
BDS Ltd., Series 2019-FL3, Class A, (1 mo. LIBOR US + 1.400%), 3.42%, 12/15/35(a)(b)			4,680		4,690,109
Bear Stearns Asset-Backed Securities I Trust:
Series 2004-HE7, Class M2, (1 mo. LIBOR US + 1.725%), 3.74%, 08/25/34(a)			240		241,775
Series 2006-HE1, Class 1M4, (1 mo. LIBOR US + 0.680%), 2.70%, 12/25/35(a)			1,693		2,237,729
Series 2006-HE7, Class 1A2, (1 mo. LIBOR US + 0.170%), 2.19%, 09/25/36(a)			3,232		3,822,034
Series 2007-FS1, Class 1A3, (1 mo. LIBOR US + 0.170%), 2.19%, 05/25/35(a)			1,146		1,233,592
Series 2007-HE1, Class 21A2, (1 mo. LIBOR US + 0.160%), 2.18%, 01/25/37(a)			647		640,162
Series 2007-HE2, Class 1A4, (1 mo. LIBOR US + 0.320%), 2.34%, 03/25/37(a)			1,033		771,646
Series 2007-HE2, Class 22A, (1 mo. LIBOR US + 0.140%), 2.16%, 03/25/37(a)			988		980,735
Series 2007-HE2, Class 23A, (1 mo. LIBOR US + 0.140%), 2.16%, 03/25/37(a)			1,784		1,891,547
Series 2007-HE3, Class 1A3, (1 mo. LIBOR US + 0.250%), 2.27%, 04/25/37(a)			1,110		1,184,896
Series 2007-HE3, Class 1A4, (1 mo. LIBOR US + 0.350%), 2.37%, 04/25/37(a)			6,164		5,402,755
Bear Stearns Asset-Backed Securities Trust, Series 2005-4, Class M2, (1 mo. LIBOR US + 1.200%), 3.22%, 01/25/36(a)			117		116,336
Benefit Street Partners CLO II Ltd., Series 2013-IIA, Class A2R, (3 mo. LIBOR US + 1.750%), 4.05%, 07/15/29(a)(b)			900		897,021
Benefit Street Partners CLO III Ltd., Series 2013-IIIA, Class A1R, (3 mo. LIBOR US + 1.250%), 3.53%, 07/20/29(a)(b)			750		752,328
Benefit Street Partners CLO IV Ltd., Series 2014-IVA, Class A1RR, (3 mo. LIBOR US + 1.250%), 3.53%, 01/20/29(a)(b)			7,830		7,837,513
Benefit Street Partners CLO V-B Ltd., Series 2018-5BA, Class A1A, (3 mo. LIBOR US + 1.090%), 3.37%, 04/20/31(a)(b)			1,450		1,441,036

Security		Par (000)		Value
Benefit Street Partners CLO VI Ltd.:
Series 2015-VIA, Class A1R, (3 mo. LIBOR US + 1.240%), 3.54%, 10/18/29(a)(b)	USD		12,030	$	12,017,751
Series 2015-VIA, Class A2R, (3 mo. LIBOR US + 1.720%), 4.02%, 10/18/29(a)(b)			3,320		3,300,592
Benefit Street Partners CLO VII Ltd., Series 2015-VIIA, Class A1AR, (3 mo. LIBOR US + 0.780%), 3.08%, 07/18/27(a)(b)			2,790		2,790,305
Benefit Street Partners CLO VIII Ltd., Series 2015-8A, Class A1AR, (3 mo. LIBOR US + 1.100%), 3.38%, 01/20/31(a)(b)			1,250		1,246,040
Benefit Street Partners CLO X Ltd.:
Series 2016-10A, Class A1R, (3 mo. LIBOR US + 1.140%), 3.44%, 01/15/29(a)(b)			1,000		1,001,579
Series 2016-10A, Class A2R, (3 mo. LIBOR US + 1.750%), 4.05%, 01/15/29(a)(b)			600		598,516
Black Diamond CLO Ltd., Series 2013-1A, Class A2R, (3 mo. LIBOR US + 1.450%), 3.75%, 02/06/26(a)(b)			1,000		999,866
BlueMountain CLO Ltd.:
Series 2013-1A, Class A1R2, (3 mo. LIBOR US + 1.230%), 3.51%, 01/20/29(a)(b)			4,012		4,015,266
Series 2013-2A, Class A1R, (3 mo. LIBOR US + 1.180%), 3.46%, 10/22/30(a)(b)			6,370		6,364,320
Series 2015-3A, Class A1R, (3 mo. LIBOR US + 1.000%), 3.28%, 04/20/31(a)(b)			2,550		2,533,649
Bowman Park CLO Ltd., Series 2014-1A, Class AR, (3 mo. LIBOR US + 1.180%), 3.33%, 11/23/25(a)(b)			3,748		3,754,504
California Street CLO XII Ltd., Series 2013-12A, Class AR, (3 mo. LIBOR US + 1.030%), 3.33%, 10/15/25(a)(b)			2,272		2,273,993
Carlyle Global Market Strategies CLO Ltd.:
Series 2013-2A, Class AR, (3 mo. LIBOR US + 0.890%), 3.19%, 01/18/29(a)(b)			1,490		1,484,006
Series 2013-4A, Class A1RR, (3 mo. LIBOR US + 1.000%), 3.30%, 01/15/31(a)(b)			1,880		1,863,888
Series 2014-1A, Class A1R2, (3 mo. LIBOR US + 0.970%), 3.27%, 04/17/31(a)(b)			3,170		3,136,763
Series 2015-3A, Class A2R, (3 mo. LIBOR US + 1.600%), 3.86%, 07/28/28(a)(b)			2,470		2,468,966
Carlyle U.S. CLO Ltd.:
Series 2016-4A, Class A2R, (3 mo. LIBOR US + 1.450%), 3.73%, 10/20/27(a)(b)			750		741,922
Series 2017-4A, Class A1, (3 mo. LIBOR US + 1.180%), 3.48%, 01/15/30(a)(b)			4,620		4,607,058
Carrington Mortgage Loan Trust:
Series 2006-FRE2, Class A2, (1 mo. LIBOR US + 0.120%), 2.14%, 10/25/36(a)			884		685,474
Series 2006-FRE2, Class A3, (1 mo. LIBOR US + 0.160%), 2.18%, 10/25/36(a)			2,943		2,292,776
Series 2006-FRE2, Class A5, (1 mo. LIBOR US + 0.080%), 2.10%, 10/25/36(a)			747		575,886
Series 2006-NC1, Class M2, (1 mo. LIBOR US + 0.420%), 2.44%, 01/25/36(a)			610		479,358
Series 2006-NC3, Class A4, (1 mo. LIBOR US + 0.240%), 2.26%, 08/25/36(a)			2,003		1,564,381

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 31

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Carrington Mortgage Loan Trust: (continued)
Series 2006-NC4, Class A3, (1 mo. LIBOR US + 0.160%), 2.18%, 10/25/36(a)	USD		934	$	867,264
Series 2006-NC5, Class A3, (1 mo. LIBOR US + 0.150%), 2.17%, 01/25/37(a)			3,978		3,290,086
Series 2007-RFC1, Class A4, (1 mo. LIBOR US + 0.220%), 2.24%, 10/25/36(a)			1,440		1,207,372
CBAM Ltd.:
Series 2017-1A, Class A1, (3 mo. LIBOR US + 1.250%), 3.53%, 07/20/30(a)(b)			6,050		6,028,841
Series 2017-2A, Class B1, (3 mo. LIBOR US + 1.750%), 4.05%, 10/17/29(a)(b)			2,955		2,949,608
Series 2017-3A, Class A, (3 mo. LIBOR US + 1.230%), 3.53%, 10/17/29(a)(b)			3,780		3,782,849
Series 2017-3A, Class B1, (3 mo. LIBOR US + 1.700%), 4.00%, 10/17/29(a)(b)			1,000		990,378
C-BASS Trust, Series 2006-CB7, Class A4, (1 mo. LIBOR US + 0.160%), 2.18%, 10/25/36(a)			635		485,092
CDO Repack SPC Ltd., Series 2006-CLF1, Class D1, 0.01%, 05/20/30(b)			540		574,576
Cedar Funding II CLO Ltd.:
Series 2013-1A, Class A1R, (3 mo. LIBOR US + 1.230%), 3.33%, 06/09/30(a)(b)			1,511		1,510,101
Series 2013-1A, Class BR, (3 mo. LIBOR US + 1.750%), 3.85%, 06/09/30(a)(b)			2,450		2,440,883
Cedar Funding IV CLO Ltd.,Series 2014-4A, Class AR, (3 mo. LIBOR US + 1.230%), 3.49%, 07/23/30(a)(b)			3,790		3,789,774
Cedar Funding IX CLO Ltd.,Series 2018-9A, Class A1, (3 mo. LIBOR US + 0.980%), 3.26%, 04/20/31(a)(b)			940		929,087
Cedar Funding V CLO Ltd.,Series 2016-5A, Class A1R, (3 mo. LIBOR US + 1.100%), 3.40%, 07/17/31(a)(b)			1,880		1,870,041
Cedar Funding VI CLO Ltd.,Series 2016-6A, Class AR, (3 mo. LIBOR US + 1.090%), 3.37%, 10/20/28(a)(b)			15,035		15,015,662
Cedar Funding VIII CLO Ltd.:
Series 2017-8A, Class A1, (3 mo. LIBOR US + 1.250%), 3.55%, 10/17/30(a)(b)			16,520		16,516,808
Series 2017-8A, Class B, (3 mo. LIBOR US + 1.700%), 4.00%, 10/17/30(a)(b)			2,628		2,597,306
Series 2017-8A, Class C, (3 mo. LIBOR US + 2.250%), 4.55%, 10/17/30(a)(b)			750		734,668
Cent CLO Ltd.:
Series 2015-24A, Class A1R, (3 mo. LIBOR US + 1.070%), 3.37%, 10/15/26(a)(b)			4,000		3,999,096
Series C17A, Class A1AR, (3 mo. LIBOR US + 1.030%), 3.30%, 04/30/31(a)(b)			7,620		7,546,060
CIFC Funding Ltd.:
Series 2013-1A, Class A2R, (3 mo. LIBOR US + 1.750%), 4.07%, 07/16/30(a)(b)			500		497,172
Series 2014-4RA, Class A1A, (3 mo. LIBOR US + 1.130%), 3.43%, 10/17/30(a)(b)			26,820		26,793,625
Series 2014-4RA, Class A2, (3 mo. LIBOR US + 1.650%), 3.95%, 10/17/30(a)(b)			250		247,981
Series 2015-2A, Class AR, (3 mo. LIBOR US + 0.780%), 3.08%, 04/15/27(a)(b)			763		760,940

Security		Par (000)		Value
CIFC Funding Ltd.: (continued)
Series 2015-2A, Class CR, (3 mo. LIBOR US + 1.700%), 4.00%, 04/15/27(a)(b)	USD		4,620	$	4,565,539
Series 2017-1A, Class B, (3 mo. LIBOR US + 1.700%), 3.98%, 04/23/29(a)(b)			2,910		2,899,697
Series 2018-1A, Class A, (3 mo. LIBOR US + 1.000%), 3.30%, 04/18/31(a)(b)			1,834		1,814,559
Citicorp Residential Mortgage Trust, Series 2007-2, Class M1, 5.01%, 06/25/37(e)			2,830		2,781,005
Citigroup Mortgage Loan Trust:
Series 2006-WFH4, Class M3, (1 mo. LIBOR US + 0.320%), 2.34%, 11/25/36(a)			3,007		2,667,213
Series 2007-AHL2, Class A3B, (1 mo. LIBOR US + 0.200%), 2.22%, 05/25/37(a)			7,050		5,146,200
Series 2007-AHL2, Class A3C, (1 mo. LIBOR US + 0.270%), 2.29%, 05/25/37(a)			3,203		2,358,684
Cloud Pass-Through Trust, Series 2019-1A, Class CLOU, 3.55%, 12/05/22(b)(d)			25,595		25,912,936
Conseco Finance Corp.:
Series 1997-3, Class M1, 7.53%, 03/15/28(d)			1,686		1,692,601
Series 1997-6, Class M1, 7.21%, 01/15/29(d)			311		315,868
Series 1998-4, Class M1, 6.83%, 04/01/30(d)			350		322,728
Series 1998-8, Class A1, 6.28%, 09/01/30			810		856,031
Series 1998-8, Class M1, 6.98%, 09/01/30(d)			2,577		2,305,502
Series 1999-5, Class A5, 7.86%, 03/01/30(d)			1,001		700,105
Series 1999-5, Class A6, 7.50%, 03/01/30(d)			1,073		724,942
Series 2001-D, Class B1, (1 mo. LIBOR US + 2.500%), 4.53%, 11/15/32(a)			2,038		1,981,783
Conseco Finance Securitizations Corp.:
Series 2000-1, Class A5, 8.06%, 09/01/29(d)			1,606		690,135
Series 2000-4, Class A5, 7.97%, 05/01/32			5,477		2,219,333
Series 2000-4, Class A6, 8.31%, 05/01/32(d)			1,375		580,839
Series 2000-5, Class A6, 7.96%, 05/01/31			2,268		1,232,513
Series 2000-5, Class A7, 8.20%, 05/01/31			4,138		2,312,880
Countrywide Asset-Backed Certificates:
Series 2003-BC3, Class A2, (1 mo. LIBOR US + 0.620%), 2.64%, 09/25/33(a)			560		552,095
Series 2004-5, Class A, (1 mo. LIBOR US + 0.900%), 2.92%, 10/25/34(a)			573		566,762
Series 2005-16, Class 1AF, 4.72%, 04/25/36(d)			3,781		3,759,643
Series 2005-16, Class 2AF3, 4.52%, 05/25/36(d)			794		806,061
Series 2005-17, Class 1AF4, 6.05%, 05/25/36(e)			2,875		2,940,190
Series 2006-11, Class 3AV2, (1 mo. LIBOR US + 0.160%), 2.18%, 09/25/46(a)			251		247,959
Series 2006-17, Class 2A2, (1 mo. LIBOR US + 0.150%), 2.17%, 03/25/47(a)			268		263,577
Series 2006-8, Class 2A3, (1 mo. LIBOR US + 0.160%), 2.18%, 12/25/35(a)			652		645,436
Series 2006-S10, Class A3, (1 mo. LIBOR US + 0.320%), 2.34%, 10/25/36(a)			5,357		5,155,371

32 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Countrywide Asset-Backed Certificates: (continued)
Series 2006-S3, Class A4, 6.64%, 01/25/29(e)	USD		452	$	499,700
Series 2006-SPS1, Class A, (1 mo. LIBOR US + 0.220%), 2.24%, 12/25/25(a)			157		175,295
Countrywide Asset-Backed Certificates Revolving Home Equity Loan Trust, Series 2004-U, Class 2A, (1 mo. LIBOR US + 0.270%), 2.30%, 03/15/34(a)			781		745,489
Credit Suisse First Boston Mortgage Securities Corp., Series 2001-MH29, Class B1, 8.10%, 09/25/31(d)			1,750		1,870,308
Credit-Based Asset Servicing & Securitization LLC:
Series 2006-CB2, Class AF4, 3.43%, 12/25/36(e)			465		426,867
Series 2006-MH1, Class B1, 6.25%, 10/25/36(b)(e)			852		878,915
Series 2006-SL1, Class A2, 6.06%, 09/25/36(b)(e)			3,131		433,752
Series 2007-CB6, Class A4, (1 mo. LIBOR US + 0.340%), 2.36%, 07/25/37(a)(b)			664		452,701
Cumberland Park CLO Ltd.,Series 2015-2A, Class CR, (3 mo. LIBOR US + 1.800%), 4.08%, 07/20/28(a)(b)			1,190		1,168,876
CWHEQ Home Equity Loan Trust, Series 2006-S5, Class A5, 6.16%, 06/25/35			516		563,459
CWHEQ Revolving Home Equity Loan Resuritization Trust:
Series 2006-RES, Class 4Q1B, (1 mo. LIBOR US + 0.300%), 2.33%, 12/15/33(a)(b)			882		821,451
Series 2006-RES, Class 5B1A, (1 mo. LIBOR US + 0.190%), 2.22%, 05/15/35(a)(b)			397		375,712
Series 2006-RES, Class 5B1B, (1 mo. LIBOR US + 0.190%), 2.22%, 05/15/35(a)(b)(c)			232		223,280
CWHEQ Revolving Home Equity Loan Trust:
Series 2005-B, Class 2A, (1 mo. LIBOR US + 0.180%), 2.21%, 05/15/35(a)			542		525,365
Series 2006-C, Class 2A, (1 mo. LIBOR US + 0.180%), 2.21%, 05/15/36(a)			3,178		3,118,897
Series 2006-H, Class 1A, (1 mo. LIBOR US + 0.150%), 2.18%, 11/15/36(a)			1,895		1,608,074
DCP Rights LLC, Series 2014-1A, Class A, 5.46%, 10/25/44(b)(c)			7,661		7,686,541
Deer Creek CLO Ltd., Series 2017-1A, Class A, (3 mo. LIBOR US + 1.180%), 3.46%, 10/20/30(a)(b)			1,000		993,139
Dorchester Park CLO DAC,Series 2015-1A, Class BR, (3 mo. LIBOR US + 1.450%), 3.73%, 04/20/28(a)(b)			3,064		3,026,781
Dryden 43 Senior Loan Fund,Series 2016-43A, Class AR, (3 mo. LIBOR US + 1.140%), 3.42%, 07/20/29(a)(b)			7,230		7,233,971
Dryden 53 CLO Ltd., Series 2017-53A, Class A, (3 mo. LIBOR US + 1.120%), 3.42%, 01/15/31(a)(b)			18,720		18,647,741
Dryden 55 CLO Ltd., Series 2018-55A, Class A1, (3 mo. LIBOR US + 1.020%), 3.32%, 04/15/31(a)(b)			250		248,620

Security		Par (000)		Value
Dryden XXV Senior Loan Fund:
Series 2012-25A, Class ARR, (3 mo. LIBOR US + 0.900%), 3.20%, 10/15/27(a)(b)	USD		11,030	$	11,030,319
Series 2012-25A, Class CRR, (3 mo. LIBOR US + 1.850%), 4.15%, 10/15/27(a)(b)			1,340		1,327,510
Dryden XXVI Senior Loan Fund, Series 2013-26A, Class AR, (3 mo. LIBOR US + 0.900%), 3.20%, 04/15/29(a)(b)			1,170		1,168,425
Dryden XXVIII Senior Loan Fund, Series 2013-28A, Class A1LR, (3 mo. LIBOR US + 1.200%), 3.36%, 08/15/30(a)(b)			9,085		9,087,830
Eaton Vance CLO Ltd.:
Series 2013-1A, Class A1RR, (3 mo. LIBOR US + 1.160%), 3.38%, 01/15/28(a)(b)			1,280		1,280,930
Series 2013-1A, Class A2RR, (3 mo. LIBOR US + 1.850%), 4.07%, 01/15/28(a)(b)			1,150		1,150,570
Elm CLO Ltd.:
Series 2014-1A, Class ARR, (3 mo. LIBOR US + 1.170%), 3.47%, 01/17/29(a)(b)			18,150		18,170,700
Series 2014-1A, Class BRR, (3 mo. LIBOR US + 1.750%), 4.05%, 01/17/29(a)(b)			1,950		1,949,479
Emerson Park CLO Ltd., Series 2013-1A, Class B1R, (3 mo. LIBOR US + 1.450%), 3.75%, 07/15/25(a)(b)			984		984,195
Finance of America Structured Securities Trust, Series 2018-HB1, Class M5, 6.00%, 09/25/28(b)(c)(d)			1,451		1,440,698
First Franklin Mortgage Loan Trust:
Series 2004-FFH3, Class M3, (1 mo. LIBOR US + 1.050%), 3.07%, 10/25/34(a)			1,000		932,009
Series 2006-FF13, Class A1, (1 mo. LIBOR US + 0.120%), 2.14%, 10/25/36(a)			2,689		2,169,458
Series 2006-FF16, Class 2A3, (1 mo. LIBOR US + 0.140%), 2.16%, 12/25/36(a)			12,978		7,407,338
Series 2006-FF17, Class A5, (1 mo. LIBOR US + 0.150%), 2.17%, 12/25/36(a)			18,510		16,218,939
Series 2006-FFH1, Class M2, (1 mo. LIBOR US + 0.400%), 2.42%, 01/25/36(a)			2,772		1,732,286
Flatiron CLO Ltd., Series 2015-1A, Class AR, (3 mo. LIBOR US + 0.890%), 3.19%, 04/15/27(a)(b)			2,604		2,604,849
Fremont Home Loan Trust, Series 2006-3, Class 1A1, (1 mo. LIBOR US + 0.140%), 2.16%, 02/25/37(a)			6,987		5,298,761
Galaxy XV CLO Ltd., Series 2013-15A, Class AR, (3 mo. LIBOR US + 1.200%), 3.50%, 10/15/30(a)(b)			1,350		1,344,686
Galaxy XXIII CLO Ltd., Series 2017-23A, Class A, (3 mo. LIBOR US + 1.280%), 3.56%, 04/24/29(a)(b)			2,603		2,603,038
Galaxy XXIX CLO Ltd.:
Series 2018-29A, Class B, (3 mo. LIBOR US + 1.400%), 3.56%, 11/15/26(a)(b)			250		248,418
Series 2018-29A, Class C, (3 mo. LIBOR US + 1.680%), 3.84%, 11/15/26(a)(b)			1,470		1,457,809

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 33

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
GE-WMC Asset-Backed Pass-Through Certificates:
Series 2005-2, Class A2C, (1 mo. LIBOR US + 0.250%), 2.27%, 12/25/35(a)	USD		368	$	366,204
Series 2005-2, Class M1, (1 mo. LIBOR US + 0.440%), 2.46%, 12/25/35(a)			4,906		4,004,056
GLG Ore Hill CLO Ltd., Series 2013-1A, Class A, (3 mo. LIBOR US + 1.120%), 3.42%, 07/15/25(a)(b)			59		58,918
GoldenTree Loan Opportunities IX Ltd., Series 2014-9A, Class AR2, (3 mo. LIBOR US + 1.110%), 3.37%, 10/29/29(a)(b)			1,830		1,826,556
Greenpoint Manufactured Housing:
Series 1999-5, Class M1B, 8.29%, 12/15/29(d)			870		927,670
Series 1999-5, Class M2, 9.23%, 12/15/29(d)			1,128		958,042
GSAA Home Equity Trust:
Series 2005-14, Class 1A2, (1 mo. LIBOR US + 0.350%), 2.37%, 12/25/35(a)			836		351,894
Series 2006-4, Class 1A1, 4.03%, 03/25/36(d)			2,896		2,512,388
Series 2006-5, Class 2A1, (1 mo. LIBOR US + 0.070%), 2.09%, 03/25/36(a)			15		7,135
Series 2007-2, Class AF3, 5.92%, 03/25/37(d)			517		173,612
GSAMP Trust:
Series 2006-FM3, Class A1, (1 mo. LIBOR US + 0.140%), 2.16%, 11/25/36(a)			5,460		3,351,558
Series 2007-H1, Class A1B, (1 mo. LIBOR US + 0.200%), 2.22%, 01/25/47(a)			1,009		613,465
Series 2007-HS1, Class M6, (1 mo. LIBOR US + 2.250%), 4.27%, 02/25/47(a)			1,300		1,346,071
Halcyon Loan Advisors Funding Ltd.:
Series 2013-2A, Class A, (3 mo. LIBOR US + 1.200%), 3.45%, 08/01/25(a)(b)			3		3,251
Series 2014-1A, Class A1R, (3 mo. LIBOR US + 1.130%), 3.43%, 04/18/26(a)(b)			64		64,469
Series 2015-2A, Class AR, (3 mo. LIBOR US + 1.080%), 3.36%, 07/25/27(a)(b)			13,570		13,555,107
Highbridge Loan Management Ltd.:
Series 12A-18, Class A1B, (3 mo. LIBOR US + 1.250%), 3.55%, 07/18/31(a)(b)			750		747,849
Series 6A-2015, Class A1R, (3 mo. LIBOR US + 1.000%), 3.29%, 02/05/31(a)(b)			11,390		11,280,380
Series 7A-2015, Class BR, (3 mo. LIBOR US + 1.180%), 3.34%, 03/15/27(a)(b)			500		491,704
Home Equity Asset Trust, Series 2007-1, Class 2A3, (1 mo. LIBOR US + 0.150%), 2.17%, 05/25/37(a)			2,490		2,076,170
Home Equity Mortgage Loan Asset-Backed Trust:
Series 2004-A, Class M2, (1 mo. LIBOR US + 2.025%), 4.04%, 07/25/34(a)			597		600,301
Series 2007-A, Class 2A2, (1 mo. LIBOR US + 0.190%), 2.21%, 04/25/37(a)			2,029		1,503,935
Series 2007-B, Class 2A3, (1 mo. LIBOR US + 0.200%), 2.22%, 07/25/37(a)			3,317		2,256,503
Home Equity Mortgage Trust, Series 2006-2, Class 1A1, 5.87%, 07/25/36(e)			2,493		741,975
Home Loan Mortgage Loan Trust, Series 2005-1, Class A3, (1 mo. LIBOR US + 0.720%), 2.75%, 04/15/36(a)			1,119		1,037,418
Home Partners of America Trust, Series 2016-2, Class A, (1 mo. LIBOR US + 1.150%), 3.18%, 10/17/33(a)(b)			746		745,504

Security		Par (000)		Value
HPS Loan Management Ltd.:
Series 10A-16, Class A1R, (3 mo. LIBOR US + 1.140%), 3.28%, 01/20/28(a)(b)	USD		4,550	$	4,546,276
Series 14A-19, Class A1, (3 mo. LIBOR US + 1.270%), 3.54%, 07/25/30(a)(b)			1,300		1,300,518
ICG U.S. CLO Ltd., Series 2015-1A, Class A1R, (3 mo. LIBOR US + 1.140%), 3.44%, 10/19/28(a)(b)			5,420		5,408,991
Invitation Homes Trust:
Series 2018-SFR3, Class A, (1 mo. LIBOR US + 1.000%), 3.03%, 07/17/37(a)(b)			2,840		2,835,727
Series 2018-SFR3, Class E, (1 mo. LIBOR US + 2.000%), 4.02%, 07/17/37(a)(b)			2,468		2,472,164
Irwin Home Equity Loan Trust, Series 2006-3, Class 2A3, 6.53%, 09/25/37(b)(e)			578		573,592
JPMorgan Mortgage Acquisition Trust, Series 2006-CW1, Class M1, (1 mo. LIBOR US + 0.270%), 2.29%, 05/25/36(a)			1,170		1,123,921
Kayne CLO II Ltd.:
Series 2018-2A, Class A, (3 mo. LIBOR US + 1.240%), 3.54%, 10/15/31(a)(b)			500		498,728
Series 2018-2A, Class B, (3 mo. LIBOR US + 1.900%), 4.20%, 10/15/31(a)(b)			250		248,660
KKR CLO 16 Ltd., Series 16, Class A1R, (3 mo. LIBOR US + 1.250%), 3.53%, 01/20/29(a)(b)			7,421		7,420,507
LCM 26 Ltd., Series 26A, Class A1, (3 mo. LIBOR US + 1.070%), 3.35%, 01/20/31(a)(b)			8,120		8,085,955
LCM XX LP:
Series 20A, Class AR, (3 mo. LIBOR US + 1.040%), 3.32%, 10/20/27(a)(b)			3,740		3,742,707
Series 20A, Class BR, (3 mo. LIBOR US + 1.550%), 3.83%, 10/20/27(a)(b)			250		248,902
LCM XXI LP, Series 21A, Class AR, (3 mo. LIBOR US + 0.880%), 3.16%, 04/20/28(a)(b)			3,430		3,416,652
LCM XXIV Ltd., Series 24A, Class A, (3 mo. LIBOR US + 1.310%), 3.59%, 03/20/30(a)(b)			500		501,085
Legacy Mortgage Asset Trust:
Series 2019-GS2, Class A1, 3.75%, 01/25/59(b)(e)			2,652		2,694,273
Series 2019-SL2, Class A, 3.38%, 02/25/59(b)(c)(d)			10,134		9,881,101
Series 2019-SL2, Class B, 0.00%, 02/25/59(b)(c)			2,551		448,655
Series 2019-SL2, Class M, 4.25%, 02/25/59(b)(c)(d)			2,083		1,593,495
Lehman ABS Manufactured Housing Contract Trust:
Series 2001-B, Class M1, 6.63%, 04/15/40(d)			4,337		4,592,715
Series 2002-A, Class C, 0.00%, 06/15/33			426		361,553
Lehman ABS Mortgage Loan Trust, Series 2007-1, Class 2A1, (1 mo. LIBOR US + 0.090%), 2.11%, 06/25/37(a)(b)			471		339,649
Litigation Fee Residual Funding LLC, Series 2015-1, Class A, 4.00%, 10/01/27(b)(c)			3,160		3,148,680
LoanCore Issuer Ltd., Series 2018-CRE1, Class A, (1 mo. LIBOR US + 1.130%), 3.16%, 05/15/28(a)(b)			7,580		7,585,668
Long Beach Mortgage Loan Trust:
Series 2006-10, Class 2A3, (1 mo. LIBOR US + 0.160%), 2.18%, 11/25/36(a)			3,636		1,718,766
Series 2006-10, Class 2A4, (1 mo. LIBOR US + 0.220%), 2.24%, 11/25/36(a)			2,160		1,034,880
Series 2006-2, Class 1A, (1 mo. LIBOR US + 0.180%), 2.20%, 03/25/46(a)			6,764		5,468,520

34 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Long Beach Mortgage Loan Trust: (continued)
Series 2006-4, Class 2A3, (1 mo. LIBOR US + 0.160%), 2.18%, 05/25/36(a)	USD		10,765	$	4,616,509
Series 2006-4, Class 2A4, (1 mo. LIBOR US + 0.260%), 2.28%, 05/25/36(a)			8,065		3,574,328
Series 2006-5, Class 2A3, (1 mo. LIBOR US + 0.150%), 2.17%, 06/25/36(a)			3,955		2,132,442
Series 2006-7, Class 2A3, (1 mo. LIBOR US + 0.160%), 2.18%, 08/25/36(a)			6,707		3,718,771
Series 2006-8, Class 2A3, (1 mo. LIBOR US + 0.160%), 2.18%, 09/25/36(a)			2,989		1,220,324
Series 2006-9, Class 2A2, (1 mo. LIBOR US + 0.110%), 2.13%, 10/25/36(a)			1,582		664,319
Series 2006-9, Class 2A3, (1 mo. LIBOR US + 0.160%), 2.18%, 10/25/36(a)			10,075		4,283,585
Series 2006-9, Class 2A4, (1 mo. LIBOR US + 0.230%), 2.25%, 10/25/36(a)			1,593		688,975
Madison Avenue Manufactured Housing Contract Trust, Series 2002-A, Class B2, (1 mo. LIBOR US + 3.250%), 5.27%, 03/25/32(a)			1,354		1,375,598
Madison Park Funding X Ltd.:
Series 2012-10A, Class AR2, (3 mo. LIBOR US + 1.220%), 3.50%, 01/20/29(a)(b)			10,710		10,709,685
Series 2012-10A, Class BR2, (3 mo. LIBOR US + 1.800%), 4.08%, 01/20/29(a)(b)			250		249,943
Madison Park Funding XI Ltd., Series 2013-11A, Class AR, (3 mo. LIBOR US + 1.160%), 3.42%, 07/23/29(a)(b)			4,830		4,835,951
Madison Park Funding XIII Ltd., Series 2014-13A, Class AR2, (3 mo. LIBOR US + 0.950%), 3.25%, 04/19/30(a)(b)			7,780		7,770,196
Madison Park Funding XIX Ltd.:
Series 2015-19A, Class A1R, (3 mo. LIBOR US + 1.250%), 3.53%, 01/22/28(a)(b)			5,420		5,419,864
Series 2015-19A, Class A2R, (3 mo. LIBOR US + 1.750%), 4.03%, 01/22/28(a)(b)			1,000		998,939
Madison Park Funding XVI Ltd., Series 2015-16A, Class A2R, (3 mo. LIBOR US + 1.900%), 4.18%, 04/20/26(a)(b)			500		501,056
Madison Park Funding XVIII Ltd., Series 2015-18A, Class A1R, (3 mo. LIBOR US + 1.190%), 3.47%, 10/21/30(a)(b)			14,970		14,977,388
Madison Park Funding XXIII Ltd., Series 2017-23A, Class A, (3 mo. LIBOR US + 1.210%), 3.47%, 07/27/30(a)(b)			250		249,799
Madison Park Funding XXVI Ltd., Series 2017-26A, Class AR, (3 mo. LIBOR US + 1.200%), 3.46%, 07/29/30(a)(b)			11,115		11,122,399
Marathon CRE Ltd., Series 2018-FL1, Class A, (1 mo. LIBOR US + 1.150%), 3.18%, 06/15/28(a)(b)			1,780		1,780,362
Marble Point CLO XI Ltd., Series 2017-2A, Class A, (3 mo. LIBOR US + 1.180%), 3.48%, 12/18/30(a)(b)			2,000		1,992,099
Mariner CLO 5 Ltd., Series 2018-5A, Class A, (3 mo. LIBOR US + 1.110%), 3.39%, 04/25/31(a)(b)			3,550		3,531,063

Security		Par (000)		Value
Mariner CLO LLC, Series 2017-4A, Class A, (3 mo. LIBOR US + 1.210%), 3.48%, 10/26/29(a)(b)	USD		1,800	$	1,796,510
Mariner Finance Issuance Trust:
Series 2019-AA, Class A, 2.96%, 07/20/32(b)			14,870		15,050,560
Series 2019-AA, Class B, 3.51%, 07/20/32(b)			2,420		2,439,220
Series 2019-AA, Class C, 4.01%, 07/20/32(b)			2,150		2,168,446
MASTR Asset-Backed Securities Trust:
Series 2006-AM2, Class A4, (1 mo. LIBOR US + 0.260%), 2.28%, 06/25/36(a)(b)			1,781		1,580,905
Series 2007-HE1, Class A4, (1 mo. LIBOR US + 0.280%), 2.30%, 05/25/37(a)			1,318		1,150,142
MASTR Specialized Loan Trust, Series 2006-3, Class A, (1 mo. LIBOR US + 0.260%), 2.28%, 06/25/46(a)(b)			556		529,212
Merrill Lynch First Franklin Mortgage Loan Trust, Series 2007-2, Class A2C, (1 mo. LIBOR US + 0.240%), 2.26%, 05/25/37(a)			2,016		1,512,789
Merrill Lynch Mortgage Investors Trust:
Series 2006-OPT1, Class M1, (1 mo. LIBOR US + 0.260%), 2.28%, 08/25/37(a)			395		202,213
Series 2006-RM3, Class A2B, (1 mo. LIBOR US + 0.090%), 2.11%, 06/25/37(a)			951		278,399
MidOcean Credit CLO III, Series 2014-3A, Class A3A2, (3 mo. LIBOR US + 0.970%), 3.25%, 04/21/31(a)(b)			2,020		1,987,563
Mill City Solar Loan Ltd., Series 2019-2GS, Class A, 3.69%, 07/20/43(b)			8,938		9,053,298
Morgan Stanley ABS Capital I, Inc. Trust:
Series 2005-HE1, Class A2MZ, (1 mo. LIBOR US + 0.600%), 2.62%, 12/25/34(a)			820		817,432
Series 2005-HE5, Class M4, (1 mo. LIBOR US + 0.870%), 2.89%, 09/25/35(a)			3,901		2,188,029
Series 2007-NC1, Class A1, (1 mo. LIBOR US + 0.130%), 2.15%, 11/25/36(a)			13,381		8,068,713
Morgan Stanley Mortgage Loan Trust, Series 2007-9SL, Class A, (1 mo. LIBOR US + 0.320%), 2.34%, 07/25/37(a)			1,239		1,183,226
Mountain Hawk II CLO Ltd., Series 2013-2A, Class BR, (3 mo. LIBOR US + 1.600%), 3.88%, 07/20/24(a)(b)			4,047		4,047,558
MP CLO III Ltd., Series 2013-1A, Class AR, (3 mo. LIBOR US + 1.250%), 3.53%, 10/20/30(a)(b)			2,820		2,812,945
MP CLO VII Ltd., Series 2015-1A, Class ARR, (3 mo. LIBOR US + 1.080%), 3.38%, 10/18/28(a)(b)			490		487,217
MP CLO VIII Ltd.:
Series 2015-2A, Class AR, (3 mo. LIBOR US + 0.910%), 3.17%, 10/28/27(a)(b)			5,910		5,910,121
Series 2015-2A, Class BR, (3 mo. LIBOR US + 1.420%), 3.68%, 10/28/27(a)(b)			3,250		3,219,717
Nationstar Home Equity Loan Trust, Series 2007-C, Class 2AV3, (1 mo. LIBOR US + 0.180%), 2.20%, 06/25/37(a)			176		175,962

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 35

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Navient Private Education Loan Trust:
Series 2014-AA, Class B, 3.50%, 08/15/44(b)	USD		6,000	$	6,147,407
Series 2014-CTA, Class B, (1 mo. LIBOR US + 1.750%), 3.78%, 10/17/44(a)(b)			8,550		8,637,054
Neuberger Berman CLO XVI-S Ltd., Series 2017-16SA, Class A, (3 mo. LIBOR US + 0.850%), 3.15%, 01/15/28(a)(b)			1,200		1,196,092
Neuberger Berman CLO XX Ltd., Series 2015-20A, Class AR, (3 mo. LIBOR US + 0.800%), 3.10%, 01/15/28(a)(b)			1,000		998,965
Neuberger Berman CLO XXIII Ltd., Series 2016-23A, Class BR, (3 mo. LIBOR US + 1.550%), 3.85%, 10/17/27(a)(b)			400		396,797
Neuberger Berman Loan Advisers CLO 26 Ltd., Series 2017-26A, Class A, (3 mo. LIBOR US + 1.170%), 3.47%, 10/18/30(a)(b)			5,520		5,510,403
Nomura Asset Acceptance Corp. Alternative Loan Trust, Series 2006-S5, Class A1, (1 mo. LIBOR US + 0.400%), 2.42%, 10/25/36(a)(b)			296		276,193
Oaktree CLO Ltd., Series 2015-1A, Class A1R, (3 mo. LIBOR US + 0.870%), 3.15%, 10/20/27(a)(b)			500		499,708
Oakwood Mortgage Investors, Inc.:
Series 2001-D, Class A2, 5.26%, 01/15/20(d)			755		545,297
Series 2001-D, Class A4, 6.93%, 09/15/31(d)			480		397,103
Series 2002-B, Class M1, 7.62%, 06/15/32(d)			4,418		3,780,604
OCP CLO Ltd.:
Series 2014-5A, Class A1R, (3 mo. LIBOR US + 1.080%), 3.35%, 04/26/31(a)(b)			660		654,202
Series 2014-7A, Class A2RR, (3 mo. LIBOR US + 1.650%), 3.93%, 07/20/29(a)(b)			750		743,492
Series 2015-10A, Class A1R, (3 mo. LIBOR US + 0.820%), 3.09%, 10/26/27(a)(b)			820		817,773
Series 2015-10A, Class BR, (3 mo. LIBOR US + 1.850%), 4.12%, 10/26/27(a)(b)			1,120		1,113,117
Series 2016-12A, Class A1R, (3 mo. LIBOR US + 1.120%), 3.42%, 10/18/28(a)(b)			7,806		7,811,382
Series 2016-12A, Class A2R, (3 mo. LIBOR US + 1.600%), 3.90%, 10/18/28(a)(b)			500		494,411
Series 2017-13A, Class A1A, (3 mo. LIBOR US + 1.260%), 3.56%, 07/15/30(a)(b)			9,170		9,174,423
Series 2017-14A, Class B, (3 mo. LIBOR US + 1.950%), 4.09%, 11/20/30(a)(b)			500		487,136
Octagon Investment Partners 18-R Ltd., Series 2018-18A, Class A1A, (3 mo. LIBOR US + 0.960%), 3.28%, 04/16/31(a)(b)			7,300		7,217,443
Octagon Investment Partners 33 Ltd., Series 2017-1A, Class A1, (3 mo. LIBOR US + 1.190%), 3.47%, 01/20/31(a)(b)			1,310		1,306,480
Octagon Investment Partners XIX Ltd., Series 2014-1A, Class AR, (3 mo. LIBOR US + 1.100%), 3.40%, 04/15/26(a)(b)			1,160		1,161,110
Octagon Investment Partners XVI Ltd., Series 2013-1A, Class A1R, (3 mo. LIBOR US + 1.020%), 3.32%, 07/17/30(a)(b)			3,580		3,534,982
Octagon Investment Partners XVII Ltd., Series 2013-1A, Class A1R2, (3 mo. LIBOR US + 1.000%), 3.28%, 01/25/31(a)(b)			7,240		7,193,652

Security		Par (000)		Value
Octagon Investment Partners XXIII Ltd., Series 2015-1A, Class CR, (3 mo. LIBOR US + 1.850%), 4.15%, 07/15/27(a)(b)	USD		1,380	$	1,355,901
OFSI Fund VI Ltd., Series 2014-6A, Class A2R, (3 mo. LIBOR US + 1.130%), 3.43%, 03/20/25(a)(b)			11,430		11,414,001
OFSI Fund VII Ltd., Series 2014-7A, Class AR, (3 mo. LIBOR US + 0.900%), 3.20%, 10/18/26(a)(b)			2,232		2,230,611
OHA Credit Partners IX Ltd., Series 2013-9A, Class DR, (3 mo. LIBOR US + 1.010%), 3.29%, 10/20/25(a)(b)			152		152,119
OHA Loan Funding Ltd.:
Series 2013-2A, Class AR, (3 mo. LIBOR US + 1.040%), 3.19%, 05/23/31(a)(b)			5,315		5,290,361
Series 2015-1A, Class AR, (3 mo. LIBOR US + 1.410%), 3.57%, 08/15/29(a)(b)			3,185		3,185,555
Series 2016-1A, Class B1, (3 mo. LIBOR US + 1.800%), 4.08%, 01/20/28(a)(b)			300		299,920
OneMain Financial Issuance Trust, Series 2019-2A, Class A, 3.14%, 10/14/36(b)			14,760		14,895,098
Option One Mortgage Acceptance Corp. Asset-Backed Certificates, Series 2003-4, Class A2, (1 mo. LIBOR US + 0.640%), 2.66%, 07/25/33(a)			882		875,261
Option One Mortgage Loan Trust:
Series 2006-3, Class 1A1, (1 mo. LIBOR US + 0.140%), 2.16%, 02/25/37(a)			1,317		992,469
Series 2007-CP1, Class 2A3, (1 mo. LIBOR US + 0.210%), 2.23%, 03/25/37(a)			2,360		1,631,680
Series 2007-FXD1, Class 1A1, 5.87%, 01/25/37(e)			2,875		2,784,100
Series 2007-FXD1, Class 2A1, 5.87%, 01/25/37(e)			7,340		7,298,670
Series 2007-FXD2, Class 1A1, 5.82%, 03/25/37(e)			12,247		12,527,514
Origen Manufactured Housing Contract Trust:
Series 2001-A, Class M1, 7.82%, 03/15/32(d)			1,523		1,538,360
Series 2007-B, Class A1, (1 mo. LIBOR US + 1.200%), 3.23%, 10/15/37(a)(b)(c)			2,173		2,136,830
Ownit Mortgage Loan Trust Series, Series 2006-2, Class A2C, 6.00%, 01/25/37(e)			1,990		1,924,822
OZLM Funding IV Ltd.:
Series 2013-4A, Class A1R, (3 mo. LIBOR US + 1.250%), 3.53%, 10/22/30(a)(b)			13,285		13,209,629
Series 2013-4A, Class A2R, (3 mo. LIBOR US + 1.700%), 3.98%, 10/22/30(a)(b)			2,120		2,099,408
OZLM Funding Ltd., Series 2012-1A, Class A2R2, (3 mo. LIBOR US + 1.850%), 4.13%, 07/22/29(a)(b)			495		494,912
OZLM VIII Ltd., Series 2014-8A, Class BRR, (3 mo. LIBOR US + 2.200%), 4.50%, 10/17/29(a)(b)			1,160		1,133,505
OZLM XIV Ltd., Series 2015-14A, Class A2AR, (3 mo. LIBOR US + 1.700%), 4.00%, 01/15/29(a)(b)			5,770		5,737,240
OZLM XIX Ltd., Series 2017-19A, Class A1, (3 mo. LIBOR US + 1.220%), 3.52%, 11/22/30(a)(b)			2,160		2,152,492
OZLM XV Ltd.:
Series 2016-15A, Class A1, (3 mo. LIBOR US + 1.490%), 3.77%, 01/20/29(a)(b)			4,740		4,746,537

36 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
OZLM XV Ltd.: (continued)
Series 2016-15A, Class A2A, (3 mo. LIBOR US + 2.100%), 4.38%, 01/20/29(a)(b)	USD		1,940	$	1,938,119
OZLM XXI Ltd., Series 2017-21A, Class B, (3 mo. LIBOR US + 1.900%), 4.18%, 01/20/31(a)(b)			930		902,249
OZLM XXIV Ltd., Series 2019-24A, Class A2A, (3 mo. LIBOR US + 2.250%), 4.41%, 07/20/32(a)(b)			750		749,394
Palmer Square CLO Ltd.:
Series 2014-1A, Class A1R2, (3 mo. LIBOR US + 1.130%), 3.43%, 01/17/31(a)(b)			4,548		4,538,151
Series 2015-1A, Class A1R2, (3 mo. LIBOR US + 1.220%), 3.37%, 05/21/29(a)(b)			10,965		10,962,397
Series 2015-1A, Class A2R2, (3 mo. LIBOR US + 1.650%), 3.80%, 05/21/29(a)(b)			2,460		2,459,171
Series 2018-1A, Class A1, (3 mo. LIBOR US + 1.030%), 3.33%, 04/18/31(a)(b)			3,360		3,337,459
Series 2018-2A, Class A1A, (3 mo. LIBOR US + 1.100%), 3.42%, 07/16/31(a)(b)			4,820		4,785,375
Series 2018-3A, Class A2, (3 mo. LIBOR US + 1.350%), 3.51%, 08/15/26(a)(b)			3,323		3,309,723
Palmer Square Loan Funding Ltd.:
, (3 mo. LIBOR US + 1.600%), 0.00%, 08/20/27(a)(b)			2,110		2,107,841
Series 2017-1A, Class A2, (3 mo. LIBOR US + 1.300%), 3.60%, 10/15/25(a)(b)			6,400		6,378,065
Parallel Ltd.:
Series 2015-1A, Class AR, (3 mo. LIBOR US + 0.850%), 3.13%, 07/20/27(a)(b)			3,990		3,985,880
Series 2015-1A, Class C1R, (3 mo. LIBOR US + 1.750%), 4.03%, 07/20/27(a)(b)			1,150		1,118,527
Series 2017-1A, Class B, (3 mo. LIBOR US + 1.700%), 3.98%, 07/20/29(a)(b)			953		944,462
Park Avenue Institutional Advisers CLO Ltd.:
Series 2017-1A, Class A1, (3 mo. LIBOR US + 1.220%), 3.40%, 11/14/29(a)(b)			6,970		6,953,562
Series 2017-1A, Class A2, (3 mo. LIBOR US + 1.700%), 3.88%, 11/14/29(a)(b)			2,940		2,928,002
Preston Ridge Partners Mortgage LLC, Series 2017-1A, Class A1, 4.25%, 01/25/22(b)(e)			115		115,483
Progress Residential Trust:
Series 2015-SFR3, Class F, 6.64%, 11/12/32(b)			500		501,239
Series 2017-SFR1, Class A, 2.77%, 08/17/34(b)			2,640		2,647,440
Series 2018-SFR1, Class F, 4.78%, 03/17/35(b)			1,620		1,644,197
Series 2018-SFR2, Class E, 4.66%, 08/17/35(b)			870		896,896
Series 2018-SFR2, Class F, 4.95%, 08/17/35(b)			1,030		1,056,053
Race Point IX CLO Ltd., Series 2015-9A, Class A1AR, (3 mo. LIBOR US + 1.210%), 3.51%, 10/15/30(a)(b)			3,730		3,729,997
Race Point X CLO Ltd., Series 2016-10A, Class A1R, (3 mo. LIBOR US + 1.100%), 3.38%, 07/25/31(a)(b)			5,550		5,500,314
Regatta Funding LP, Series 2013-2A, Class A1R2, (3 mo. LIBOR US + 1.250%), 3.55%, 01/15/29(a)(b)			1,300		1,302,699

Security		Par (000)		Value
Regatta VI Funding Ltd., Series 2016-1A, Class AR, (3 mo. LIBOR US + 1.080%), 3.36%, 07/20/28(a)(b)	USD		10,290	$	10,272,684
Riserva CLO Ltd., Series 2016-3A, Class AR, (3 mo. LIBOR US + 1.140%), 3.44%, 10/18/28(a)(b)			4,670		4,669,623
Rockford Tower CLO Ltd.:
Series 2017-1A, Class A, (3 mo. LIBOR US + 1.370%), 3.67%, 04/15/29(a)(b)			9,130		9,130,728
Series 2017-1A, Class B, (3 mo. LIBOR US + 1.800%), 4.10%, 04/15/29(a)(b)			3,870		3,856,311
Series 2017-2A, Class B, (3 mo. LIBOR US + 1.750%), 4.05%, 10/15/29(a)(b)			6,049		6,007,793
Series 2017-2A, Class C, (3 mo. LIBOR US + 2.300%), 4.60%, 10/15/29(a)(b)			940		927,166
Series 2017-3A, Class A, (3 mo. LIBOR US + 1.190%), 3.47%, 10/20/30(a)(b)			9,076		9,058,518
Romark WM-R Ltd., Series 2018-1A, Class A1, (3 mo. LIBOR US + 1.030%), 3.31%, 04/20/31(a)(b)			2,910		2,878,422
RR 3 Ltd., Series 2018-3A, Class A1R2, (3 mo. LIBOR US + 1.090%), 3.39%, 01/15/30(a)(b)			2,020		2,006,162
RR 6 Ltd., Series 2019-6A, Class A1A, (3 mo. LIBOR US + 1.250%), 3.63%, 04/15/30(a)(b)			9,840		9,839,773
SACO I Trust, Series 2006-9, Class A1, (1 mo. LIBOR US + 0.300%), 2.32%, 08/25/36(a)			375		367,824
Securitized Asset-Backed Receivables LLC Trust:
Series 2006-WM4, Class A1, (1 mo. LIBOR US + 0.190%), 2.21%, 11/25/36(a)(b)			2,848		1,665,306
Series 2006-WM4, Class A2A, (1 mo. LIBOR US + 0.080%), 2.10%, 11/25/36(a)			1,382		521,332
Series 2006-WM4, Class A2C, (1 mo. LIBOR US + 0.160%), 2.18%, 11/25/36(a)			4,140		1,589,198
Security National Mortgage Loan Trust, Series 2007-1A, Class 2A, (1 mo. LIBOR US + 0.350%), 2.37%, 04/25/37(a)(b)			667		660,000
Seneca Park CLO Ltd., Series 2014-1A, Class AR, (3 mo. LIBOR US + 1.120%), 3.42%, 07/17/26(a)(b)			211		211,815
SG Mortgage Securities Trust, Series 2006-FRE2, Class A2C, (1 mo. LIBOR US + 0.160%), 2.18%, 07/25/36(a)			974		298,050
Silver Creek CLO Ltd.:
Series 2014-1A, Class AR, (3 mo. LIBOR US + 1.240%), 3.52%, 07/20/30(a)(b)			3,920		3,920,590
Series 2014-1A, Class CR, (3 mo. LIBOR US + 2.300%), 4.58%, 07/20/30(a)(b)			500		494,555
SLM Private Credit Student Loan Trust:
Series 2004-A, Class A3, (3 mo. LIBOR US + 0.400%), 2.52%, 06/15/33(a)			2,153		2,124,221
Series 2004-B, Class A3, (3 mo. LIBOR US + 0.330%), 2.45%, 03/15/24(a)			8,675		8,625,978
Series 2006-B, Class A5, (3 mo. LIBOR US + 0.270%), 2.39%, 12/15/39(a)			544		530,693
SMB Private Education Loan Trust, Series 2015-B, Class B, 3.50%, 12/17/40(b)			2,480		2,545,889
Sound Point CLO II Ltd., Series 2013-1A, Class A1R, (3 mo. LIBOR US + 1.070%), 3.34%, 01/26/31(a)(b)			500		495,737
Sound Point CLO XI Ltd., Series 2016-1A, Class CR, (3 mo. LIBOR US + 2.250%), 4.53%, 07/20/28(a)(b)			440		435,443

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 37

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Sound Point CLO XIV Ltd.:
Series 2016-3A, Class AR, (3 mo. LIBOR US + 1.150%), 3.30%, 01/23/29(a)(b)	USD		9,440	$	9,470,709
Series 2016-3A, Class C, (3 mo. LIBOR US + 2.650%), 4.91%, 01/23/29(a)(b)			1,000		1,002,529
Sound Point CLO XV Ltd., Series 2017-1A, Class AR, (3 mo. LIBOR US + 1.150%), 0.00%, 01/23/29(a)(b)(c)			1,720		1,720,000
Sound Point CLO XVIII Ltd., Series 2017-4A, Class B, (3 mo. LIBOR US + 1.800%), 4.08%, 01/21/31(a)(b)			500		479,520
Sound Point CLO XXIII, Series 2019-2A, Class A1, (3 mo. LIBOR US + 1.400%), 3.88%, 04/15/32(a)(b)			19,610		19,596,822
Soundview Home Loan Trust, Series 2004-WMC1, Class M2, (1 mo. LIBOR US + 0.795%), 2.81%, 01/25/35(a)			51		49,943
Steele Creek CLO Ltd., Series 2017-1A, Class A, (3 mo. LIBOR US + 1.250%), 3.55%, 01/15/30(a)(b)			4,140		4,127,407
Stewart Park CLO Ltd., Series 2015-1A, Class CR, (3 mo. LIBOR US + 1.800%), 4.10%, 01/15/30(a)(b)			1,630		1,584,186
Structured Asset Securities Corp. Assistance Loan Trust, Series 2003-AL2, Class A, 3.36%, 01/25/31(b)			303		301,158
Structured Asset Securities Corp. Mortgage Pass-Through Certificates, Series 2004-23XS, Class 2A1, (1 mo. LIBOR US + 0.300%), 2.32%, 01/25/35(a)			554		550,107
Symphony CLO XVII Ltd., Series 2016-17A, Class AR, (3 mo. LIBOR US + 0.880%), 3.18%, 04/15/28(a)(b)			3,620		3,603,870
Symphony CLO XVIII Ltd.:
Series 2016-18A, Class AR, (3 mo. LIBOR US + 1.150%), 3.41%, 01/23/28(a)(b)			4,140		4,142,215
Series 2016-18A, Class B, (3 mo. LIBOR US + 1.800%), 4.06%, 01/23/28(a)(b)			300		299,423
TCI-Flatiron CLO Ltd., Series 2017-1A, Class A, (3 mo. LIBOR US + 1.200%), 3.32%, 11/17/30(a)(b)			3,290		3,286,394
Thacher Park CLO Ltd., Series 2014-1A, Class AR, (3 mo. LIBOR US + 1.160%), 3.44%, 10/20/26(a)(b)			385		384,593
THL Credit Wind River CLO Ltd.:
Series 2012-1A, Class BR2, (3 mo. LIBOR US + 1.450%), 3.75%, 01/15/26(a)(b)			920		918,583
Series 2016-1A, Class AR, (3 mo. LIBOR US + 1.050%), 3.35%, 07/15/28(a)(b)			4,880		4,873,972
TIAA CLO II Ltd., Series 2017-1A, Class A, (3 mo. LIBOR US + 1.280%), 3.56%, 04/20/29(a)(b)			2,340		2,340,806
TIAA CLO III Ltd., Series 2017-2A, Class A, (3 mo. LIBOR US + 1.150%), 3.47%, 01/16/31(a)(b)			1,467		1,454,394
TICP CLO I Ltd., Series 2015-1A, Class AR, (3 mo. LIBOR US + 0.800%), 3.08%, 07/20/27(a)(b)			1,000		996,457
TICP CLO VI Ltd.:
Series 2016-6A, Class AR, (3 mo. LIBOR US + 1.200%), 3.50%, 01/15/29(a)(b)			1,490		1,491,284
Series 2016-6A, Class BR, (3 mo. LIBOR US + 1.700%), 4.00%, 01/15/29(a)(b)			5,360		5,341,161

Security		Par (000)		Value
Towd Point Mortgage Trust:
Series 2019-SJ2, Class A2, 4.25%, 11/25/58(b)(d)	USD		3,280	$	3,381,653
Series 2019-SJ2, Class M1, 4.50%, 11/25/58(b)(d)			8,260		8,612,474
Trestles CLO Ltd., Series 2017-1A, Class A1A, (3 mo. LIBOR US + 1.290%), 3.57%, 07/25/29(a)(b)			250		250,330
Tricon American Homes Trust:
Series 2017-SFR2, Class F, 5.10%, 01/17/36(b)			2,010		2,090,520
Series 2018-SFR1, Class E, 4.56%, 05/17/37(b)			890		942,038
Series 2018-SFR1, Class F, 4.96%, 05/17/37(b)			610		637,425
Venture CLO Ltd.:
Series 2018-32A, Class A2A, (3 mo. LIBOR US + 1.070%), 3.37%, 07/18/31(a)(b)			1,480		1,467,535
Series 2018-35A, Class AS, (3 mo. LIBOR US + 1.150%), 3.43%, 10/22/31(a)(b)			2,810		2,806,997
Venture XVIII CLO Ltd., Series 2014-18A, Class AR, (3 mo. LIBOR US + 1.220%), 3.52%, 10/15/29(a)(b)			9,820		9,837,953
Venture XXIV CLO Ltd., Series 2016-24A, Class AR, (3 mo. LIBOR US + 1.180%), 3.46%, 10/20/28(a)(b)			3,300		3,300,000
Vericrest Opportunity Loan Trust, Series 2019-NPL2, Class A1, 3.97%, 02/25/49(b)(e)			1,489		1,494,193
Vibrant CLO V Ltd., Series 2016-5A, Class A, (3 mo. LIBOR US + 1.550%), 3.83%, 01/20/29(a)(b)			2,480		2,480,932
Vibrant CLO VII Ltd., Series 2017-7A, Class A1, (3 mo. LIBOR US + 1.270%), 3.55%, 09/15/30(a)(b)			1,750		1,741,095
Voya CLO Ltd.:
Series 2015-2A, Class BR, (3 mo. LIBOR US + 1.500%), 3.76%, 07/23/27(a)(b)			780		772,136
Series 2017-4A, Class A1, (3 mo. LIBOR US + 1.130%), 3.43%, 10/15/30(a)(b)			6,640		6,628,679
Series 2019-1A, Class A, (3 mo. LIBOR US + 1.170%), 3.81%, 04/15/29(a)(b)			10,580		10,579,816
Wachovia Asset Securitization Issuance II LLC Trust, Series 2007-HE2A, Class A, (1 mo. LIBOR US + 0.130%), 2.15%, 07/25/37(a)(b)			1,740		1,633,283
Washington Mutual Asset-Backed Certificates Trust:
Series 2006-HE4, Class 2A2, (1 mo. LIBOR US + 0.180%), 2.20%, 09/25/36(a)			5,283		2,431,209
Series 2006-HE5, Class 1A, (1 mo. LIBOR US + 0.155%), 2.17%, 10/25/36(a)			2,090		1,674,596
Series 2007-HE2, Class 2A2, (1 mo. LIBOR US + 0.220%), 2.24%, 02/25/37(a)			5,483		2,287,086
Series 2007-HE2, Class 2A3, (1 mo. LIBOR US + 0.250%), 2.27%, 04/25/37(a)			9,594		5,047,793
Series 2007-HE2, Class 2A4, (1 mo. LIBOR US + 0.360%), 2.38%, 04/25/37(a)			1,031		553,199

38 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security			Par (000)		Value
Wellfleet CLO Ltd.:
Series 2017-1A, Class A1, (3 mo. LIBOR US + 1.320%), 3.60%, 04/20/29(a)(b)		USD		2,160	$	2,159,137
Series 2017-3A, Class B, (3 mo. LIBOR US + 1.950%), 4.25%, 01/17/31(a)(b)				750		702,209
Westcott Park CLO Ltd., Series 2016-1A, Class AR, (3 mo. LIBOR US + 1.210%), 3.49%, 07/20/28(a)(b)				5,610		5,623,828
Yale Mortgage Loan Trust, Series 2007-1, Class A, (1 mo. LIBOR US + 0.400%), 2.42%, 06/25/37(a)(b)				2,545		1,060,718
York CLO-3 Ltd., Series 2016-1A, Class BR, (3 mo. LIBOR US + 1.750%), 4.03%, 10/20/29(a)(b)				3,380		3,358,726
York CLO-4 Ltd., Series 2016-2A, Class A, (3 mo. LIBOR US + 1.630%), 3.91%, 01/20/30(a)(b)				3,380		3,386,162
Total Asset-Backed Securities — 10.3% (Cost: $1,626,093,796)						1,613,368,478
	Shares
Common Stocks — 0.2%
Diversified Financial Services — 0.0%
Pure Acquisition Corp.(f)				900		9,225
Diversified Telecommunication Services — 0.0%
Intelsat SA(f)				35,775		815,670
Energy Equipment & Services — 0.0%
Vantage Drilling Co.(f)				311,000		2,270
Entertainment — 0.0%
Sciplay Corp.(f)				43,008		460,186
Equity Real Estate Investment Trusts (REITs) — 0.0%
Gaming and Leisure Properties, Inc.				67,680		2,588,083
VICI Properties, Inc.				106,956		2,422,553
						5,010,636
Health Care Providers & Services — 0.0%
HCA Healthcare, Inc.				38,223		4,602,814
Hotels, Restaurants & Leisure — 0.0%
Golden Entertainment, Inc.(f)				35,439		470,984
Target Hospitality Corp.(f)				236,970		1,613,766
						2,084,750
Household Durables — 0.1%
Beazer Homes USA, Inc.(f)				18,420		274,458
Century Communities, Inc.(f)				78,526		2,405,251
M/I Homes, Inc.(f)				22,460		845,619
Taylor Morrison Home Corp.(f)				106,945		2,774,153
William Lyon Homes, Class A(f)				93,411		1,901,848
						8,201,329
Independent Power and Renewable Electricity Producers — 0.0%
Vistra Energy Corp.				23,312		623,130
IT Services — 0.0%
Everi Holdings, Inc.(f)				73,000		617,580
Media — 0.0%
Altice USA, Inc., Class A(f)				91,753		2,631,476
Metals & Mining — 0.0%
Northern Graphite Corp.(f)				99,612		6,391
Oil, Gas & Consumable Fuels — 0.1%
Centennial Resource Development, Inc.(f)				41,400		186,921

Security			Shares		Value
Oil, Gas & Consumable Fuels (continued)
Rattler Midstream LP(f)				238,119	$	4,243,281
Sunoco LP				151,742		4,772,286
						9,202,488
Real Estate Management & Development — 0.0%
Forestar Group, Inc.(f)				22,564		412,470
Total Common Stocks — 0.2% (Cost: $32,783,440)						34,680,415
	Par       (000)
Corporate Bonds — 37.1%
Aerospace & Defense — 1.4%
Airbus SE, 3.95%, 04/10/47(b)		USD		4,240		4,911,890
Arconic, Inc.:
6.15%, 08/15/20				4,555		4,700,578
5.40%, 04/15/21				312		322,775
BAE Systems Holdings, Inc.:
3.80%, 10/07/24(b)				595		624,888
3.85%, 12/15/25(b)				10,355		10,887,667
4.75%, 10/07/44(b)				259		303,697
Boeing Co.:
3.25%, 02/01/35				1,155		1,196,829
3.38%, 06/15/46				837		839,602
3.85%, 11/01/48				2,782		3,029,555
3.83%, 03/01/59				2,575		2,745,105
General Dynamics Corp., 3.75%, 05/15/28				3,603		4,009,940
L3 Technologies, Inc., 4.95%, 02/15/21				250		256,829
L3Harris Technologies, Inc.:
2.70%, 04/27/20				1,299		1,301,600
3.85%, 06/15/23(b)				16,190		17,053,649
3.83%, 04/27/25				49		52,330
3.85%, 12/15/26(b)				10,802		11,603,744
4.40%, 06/15/28(b)				13,622		15,303,526
4.85%, 04/27/35				77		91,158
6.15%, 12/15/40				80		109,337
5.05%, 04/27/45				4,390		5,508,138
Lockheed Martin Corp.:
2.90%, 03/01/25				1,370		1,418,365
3.55%, 01/15/26				1,161		1,244,738
3.60%, 03/01/35				21,240		22,961,317
3.80%, 03/01/45				37		41,213
Northrop Grumman Corp.:
2.55%, 10/15/22				32		32,428
2.93%, 01/15/25				10,272		10,588,821
3.25%, 01/15/28				14,045		14,740,191
3.85%, 04/15/45				2,310		2,546,982
4.03%, 10/15/47				2,724		3,089,646
Raytheon Co.:
7.20%, 08/15/27				2,353		3,140,841
7.00%, 11/01/28				7,205		9,543,288
4.20%, 12/15/44				2,312		2,745,732
Textron, Inc.:
3.65%, 03/15/27				2,985		3,114,661
3.90%, 09/17/29				5,706		6,109,557
TransDigm, Inc., 6.00%, 07/15/22				252		255,780
United Technologies Corp.:
3.35%, 08/16/21				358		367,246
1.95%, 11/01/21				13,880		13,869,070
2.30%, 05/04/22				33		33,305
1.15%, 05/18/24		EUR		5,035		5,714,338
4.13%, 11/16/28		USD		14,025		15,867,687
5.40%, 05/01/35				2,411		3,080,788
6.13%, 07/15/38				4,600		6,322,379

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 39

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Aerospace & Defense (continued)
United Technologies Corp.: (continued)
4.50%, 06/01/42	USD		9,371	$	11,222,215
					222,903,425
Air Freight & Logistics — 0.1%
FedEx Corp.:
0.45%, 08/05/25	EUR		1,610		1,756,023
1.30%, 08/05/31			1,270		1,396,819
3.90%, 02/01/35	USD		2,069		2,116,763
3.88%, 08/01/42			6,233		6,019,979
GLP China Holdings Ltd., 4.97%, 02/26/24			925		974,141
United Parcel Service, Inc.:
3.40%, 03/15/29			4,084		4,370,165
2.50%, 09/01/29			4,755		4,736,795
4.88%, 11/15/40			350		422,824
4.25%, 03/15/49			149		172,147
XPO Logistics, Inc., 6.50%, 06/15/22(b)			100		101,950
					22,067,606
Airlines — 0.8%
Air Canada Pass-Through Trust:
Series 2015, Class 2B, 5.00%, 06/15/25(b)			1,426		1,488,750
Series 2017-1, Class B, 3.70%, 07/15/27(b)			23		22,600
Series 2017, Class 1AA, 3.30%, 07/15/31(b)			2,086		2,151,755
American Airlines Group, Inc.:
5.50%, 10/01/19(b)			312		312,000
4.63%, 03/01/20(b)			3,144		3,163,650
American Airlines Pass-Through Trust:
Series 2014-1, Class B, 4.38%, 04/01/24			77		79,135
Series 2015-1, Class B, 3.70%, 11/01/24			767		775,001
Series 2015-2, Class B, 4.40%, 03/22/25			6,244		6,454,733
Series 2016-1, Class B, 5.25%, 07/15/25			4,196		4,459,621
Series 2019-1, Class B, 4.00%, 12/15/25(c)			2,006		2,028,668
Series 2017-1, Class B, 4.95%, 08/15/26			1,469		1,550,062
Series 2017-2, Class B, 3.70%, 04/15/27			1,699		1,708,296
Series 2016-3, Class B, 3.75%, 04/15/27			82		83,697
Series 2019-1, Class A, 3.50%, 12/15/27(c)			5,099		5,220,356
Series 2015-2, Class AA, 3.60%, 03/22/29			1,096		1,149,349
Series 2019-1, Class B, 3.85%, 08/15/29			5,695		5,752,353
Series 2016-2, Class AA, 3.20%, 12/15/29			1,994		2,046,349
Series 2016-3, Class AA, 3.00%, 04/15/30			4,504		4,586,595
Series 2017-1, Class AA, 3.65%, 08/15/30			1,532		1,627,644
Series 2017-2, Class AA, 3.35%, 04/15/31			1,957		2,014,639
Series 2019-1, Class AA, 3.15%, 08/15/33			5,280		5,423,152
American Airlines, Inc.:
Series 2019-1C, 4.13%, 06/15/22(c)			15,927		15,927,000
Series 2011-1B, 4.87%, 04/22/25(c)			1,342		1,389,072
ANA Holdings, Inc.:
0.00%, 09/16/22(g)(h)	JPY		10,000		91,334
0.00%, 09/19/24(g)(h)			60,000		551,335
Avianca Holdings SA/Avianca Leasing LLC/Grupo Taca Holdings Ltd., 8.38%, 05/10/20	USD		383		357,866
Continental Airlines Pass-Through Trust, Series 2012, Class B, 6.25%, 10/11/21			29		29,767
Delta Air Lines Pass-Through Trust, Series 2019-1, Class 1AA, 3.20%, 10/25/25			4,265		4,455,654
Delta Air Lines, Inc., 2.88%, 03/13/20			26,462		26,518,495
Gol Finance, Inc., 7.00%, 01/31/25(b)			2,093		2,041,002
Turkish Airlines Pass-Through Trust, Series 2015-1, Class A, 4.20%, 09/15/28(b)			1,452		1,341,655
United Airlines Pass-Through Trust:
Series 2014-1, Class B, 4.75%, 10/11/23			424		436,319
Series 2014-2, Class B, 4.63%, 03/03/24			488		502,482
Series 2016-2, Class B, 3.65%, 04/07/27			266		268,756
Series 2016-1, Class B, 3.65%, 07/07/27			479		487,066
Series 2018-1, Class B, 4.60%, 09/01/27			2,113		2,202,886
Series 2015-1, Class AA, 3.45%, 06/01/29			774		806,297
Series 2019-2, Class B, 3.50%, 11/01/29			4,006		4,012,608

Security		Par (000)		Value
Airlines (continued)
United Airlines Pass-Through Trust: (continued)
Series 2016-1, Class AA, 3.10%, 01/07/30	USD		291	$	297,657
Series 2016-2, Class AA, 2.88%, 04/07/30			1,922		1,940,731
Series 2018-1, Class AA, 3.50%, 09/01/31			1,283		1,342,871
Series 2019-2, Class AA, 2.70%, 11/01/33			3,365		3,355,705
US Airways Pass-Through Trust:
Series 2012-2, Class B, 6.75%, 12/03/22			147		154,364
Series 2013-1, Class B, 5.38%, 05/15/23			570		594,622
					121,203,949
Auto Components — 0.0%
Aptiv PLC, 5.40%, 03/15/49			615		703,380
Lear Corp., 5.25%, 05/15/49			355		365,158
					1,068,538
Automobiles — 0.4%
BMW US Capital LLC, 2.80%, 04/11/26(b)			2,019		2,044,894
Daimler Finance North America LLC:
3.10%, 05/04/20(b)			10,030		10,087,979
2.30%, 02/12/21(b)			9,005		9,011,965
3.35%, 05/04/21(b)			13,377		13,597,370
3.75%, 11/05/21(b)			910		935,633
Daimler International Finance BV, 0.25%, 08/09/21	EUR		370		405,397
Fiat Chrysler Automobiles NV, 4.50%, 04/15/20	USD		336		338,386
General Motors Co.:
5.00%, 04/01/35			259		259,969
6.60%, 04/01/36			3,030		3,471,580
6.25%, 10/02/43			2,689		2,945,885
5.40%, 04/01/48			737		738,248
Toyota Motor Corp., 2.76%, 07/02/29			175		180,971
Volkswagen Group of America Finance LLC:
2.50%, 09/24/21(b)			2,387		2,392,917
2.70%, 09/26/22(b)			4,036		4,055,373
4.75%, 11/13/28(b)			900		1,001,209
Volkswagen International Finance NV:
1.88%, 03/30/27	EUR		2,600		2,994,833
4.13%, 11/16/38			1,200		1,708,019
Volkswagen Leasing GmbH, 1.00%, 02/16/23			650		722,554
					56,893,182
Banks — 7.4%
ABN AMRO Bank NV, 2.65%, 01/19/21(b)	USD		8,540		8,577,828
Australia & New Zealand Banking Group Ltd.:
2.55%, 11/23/21			1,361		1,373,955
2.63%, 11/09/22			1,075		1,093,214
Banco de Sabadell SA, 0.88%, 07/22/25	EUR		3,900		4,307,583
Banco Espirito Santo SA:
2.63%, 05/08/17(f)(i)			400		82,837
4.75%, 01/15/18(f)(i)			2,200		455,601
4.00%, 01/21/19(f)(i)			6,300		1,304,675
Banco Internacional del Peru SAA Interbank, 3.25%, 10/04/26(b)	USD		1,709		1,706,864
Banco Santander SA:
3.85%, 04/12/23			1,600		1,667,347
2.71%, 06/27/24			6,200		6,268,057
3.31%, 06/27/29			6,400		6,612,035
Banco Votorantim SA:
4.00%, 09/24/22(b)			2,516		2,557,514
4.50%, 09/24/24(b)			2,745		2,820,487
Bangkok Bank PCL, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 1.900%), 3.73%, 09/25/34(j)			2,075		2,103,428
Bank Mandiri Persero Tbk PT, 3.75%, 04/11/24			705		728,353
Bank of America Corp.:
2.63%, 10/19/20			5,775		5,811,651
2.63%, 04/19/21			12		12,107
(3 mo. LIBOR US + 0.660%), 2.37%, 07/21/21(j)			14,085		14,107,220

40 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Banks (continued)
Bank of America Corp.: (continued)
(3 mo. LIBOR US + 0.630%), 2.33%, 10/01/21(j)	USD		37,283	$	37,324,785
(3 mo. LIBOR US + 0.370%), 2.74%, 01/23/22(j)			83		83,470
(3 mo. LIBOR US + 0.630%), 3.50%, 05/17/22(j)			8,468		8,635,996
3.30%, 01/11/23			1,307		1,350,350
(3 mo. LIBOR US + 1.160%), 3.12%, 01/20/23(j)			471		480,408
(3 mo. LIBOR US + 1.021%), 2.88%, 04/24/23(j)			768		779,238
(3 mo. LIBOR US + 0.930%), 2.82%, 07/21/23(j)			7,970		8,091,120
(3 mo. LIBOR US + 0.790%), 3.00%, 12/20/23(j)			401		409,528
(3 mo. LIBOR US + 0.780%), 3.55%, 03/05/24(j)			733		761,781
4.00%, 04/01/24			1,947		2,087,090
4.20%, 08/26/24			3,424		3,672,563
(3 mo. LIBOR US + 0.970%), 3.46%, 03/15/25(j)			5,933		6,182,808
3.95%, 04/21/25			3,619		3,835,168
(3 mo. LIBOR US + 0.810%), 3.37%, 01/23/26(j)			331		344,285
4.45%, 03/03/26			10,821		11,792,618
3.50%, 04/19/26			192		203,842
4.25%, 10/22/26			137		147,919
(3 mo. LIBOR US + 1.060%), 3.56%, 04/23/27(j)			6,820		7,193,732
Series L, 4.18%, 11/25/27			655		707,083
(3 mo. LIBOR US + 1.575%), 3.82%, 01/20/28(j)			17,716		19,017,125
(3 mo. LIBOR US + 1.512%), 3.71%, 04/24/28(j)			21,048		22,386,216
(3 mo. LIBOR US + 1.370%), 3.59%, 07/21/28(j)			1,235		1,303,864
(3 mo. LIBOR US + 1.040%), 3.42%, 12/20/28(j)			37,230		38,883,047
(3 mo. LIBOR US + 1.070%), 3.97%, 03/05/29(j)			8,037		8,708,139
(3 mo. LIBOR US + 1.310%), 4.27%, 07/23/29(j)			2,256		2,509,530
(3 mo. LIBOR US + 1.210%), 3.97%, 02/07/30(j)			3,926		4,290,387
(3 mo. LIBOR US + 1.180%), 3.19%, 07/23/30(j)			1,801		1,857,410
6.11%, 01/29/37			150		196,462
4.75%, 04/21/45			84		101,110
Bank of Montreal:
3.10%, 07/13/20			185		186,594
3.10%, 04/13/21			1,274		1,295,850
1.90%, 08/27/21			281		280,582
2.90%, 03/26/22			1,794		1,828,468
2.55%, 11/06/22			364		369,788
3.30%, 02/05/24			385		400,627
2.50%, 06/28/24			1,387		1,401,719
Barclays PLC:
(3 mo. LIBOR US + 1.610%), 3.93%, 05/07/25(j)			1,650		1,705,398
(3 mo. LIBOR US + 1.902%), 4.97%, 05/16/29(j)			9,280		10,180,501
5.25%, 08/17/45			933		1,052,087
4.95%, 01/10/47			3,853		4,229,393
BAWAG PSK Bank fuer Arbeit und Wirtschaft und Oesterreichische Postsparkasse AG, 0.38%, 09/03/27	EUR		3,000		3,168,875

Security		Par (000)		Value
Banks (continued)
BBVA Bancomer SA, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 4.308%), 5.88%, 09/13/34(b)(j)	USD		4,634	$	4,605,037
BNP Paribas SA:
5.00%, 01/15/21			190		197,041
3.50%, 03/01/23(b)			7,725		7,973,300
3.38%, 01/09/25(b)			988		1,020,251
(3 mo. LIBOR US + 2.235%), 4.71%, 01/10/25(b)(j)			10,062		10,876,574
1.50%, 05/25/28	EUR		14,015		16,958,536
BPCE SA:
3.00%, 05/22/22(b)	USD		2,017		2,046,748
2.70%, 10/01/29(b)			11,639		11,561,352
Citibank NA:
3.40%, 07/23/21			10,990		11,248,139
(3 mo. LIBOR US + 0.530%), 3.17%, 02/19/22(j)			2,510		2,543,002
3.65%, 01/23/24			33,670		35,709,262
Citigroup, Inc.:
2.75%, 04/25/22			62		62,923
4.05%, 07/30/22			27		28,277
(3 mo. LIBOR US + 1.023%), 4.04%, 06/01/24(j)			256		270,497
(3 mo. LIBOR US + 0.897%), 3.35%, 04/24/25(j)			858		888,982
4.40%, 06/10/25			4,656		5,011,671
5.50%, 09/13/25			759		860,464
3.20%, 10/21/26			282		291,513
4.45%, 09/29/27			6,216		6,782,123
(3 mo. LIBOR US + 1.563%), 3.89%, 01/10/28(j)			13,340		14,289,240
(3 mo. LIBOR US + 1.390%), 3.67%, 07/24/28(j)			23,362		24,732,168
(3 mo. LIBOR US + 1.151%), 3.52%, 10/27/28(j)			190		198,700
8.13%, 07/15/39			121		198,379
4.65%, 07/23/48			238		291,267
Citizens Bank N.A., 2.25%, 03/02/20			14,776		14,780,603
Cooperatieve Rabobank UA, 1.38%, 02/03/27	EUR		2,945		3,524,332
Credit Agricole SA, 1.25%, 04/14/26			3,200		3,755,915
Danske Bank A/S:
5.00%, 01/12/22(b)	USD		12,395		13,031,473
3.88%, 09/12/23(b)			1,060		1,098,950
5.38%, 01/12/24(b)			8,820		9,688,162
(3 mo. LIBOR US + 1.591%), 3.24%, 12/20/25(b)(j)			870		876,991
Fifth Third Bancorp, 3.65%, 01/25/24			2,460		2,593,135
HSBC Holdings PLC:
5.10%, 04/05/21			5,085		5,301,180
(3 mo. LIBOR US + 0.987%), 3.95%, 05/18/24(j)			1,875		1,962,284
(3 mo. LIBOR US + 1.546%), 4.04%, 03/13/28(j)			14,472		15,368,548
(3 mo. LIBOR US + 1.535%), 4.58%, 06/19/29(j)			400		443,029
(3 mo. LIBOR US + 1.610%), 3.97%, 05/22/30(j)			1,135		1,211,830
HSBC USA, Inc., 2.35%, 03/05/20			18,862		18,887,132
Huntington National Bank, 3.25%, 05/14/21			3,780		3,843,798
ING Bank NV, 0.00%, 04/08/22	EUR		3,000		3,280,031
ING Groep NV:
4.10%, 10/02/23	USD		14,146		15,016,021
3.55%, 04/09/24			4,289		4,480,713
4.63%, 01/06/26(b)			5,150		5,702,289
Intesa Sanpaolo SpA, 6.50%, 02/24/21(b)			3,034		3,186,845
JPMorgan Chase & Co.:
4.25%, 10/15/20			266		272,183
2.55%, 03/01/21			7,831		7,874,956

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 41

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Banks (continued)
JPMorgan Chase & Co.: (continued)
4.63%, 05/10/21	USD		5,281	$	5,488,651
4.35%, 08/15/21			249		259,024
(3 mo. LIBOR US + 0.610%), 3.51%, 06/18/22(j)			7,676		7,849,183
2.97%, 01/15/23			7,538		7,674,380
3.20%, 01/25/23			1,190		1,228,959
(3 mo. LIBOR US + 0.695%), 3.21%, 04/01/23(j)			25,500		26,121,381
(3 mo. LIBOR US + 0.935%), 2.78%, 04/25/23(j)			2,204		2,232,103
3.38%, 05/01/23			232		239,941
2.70%, 05/18/23			7,711		7,840,635
3.88%, 02/01/24			310		330,296
(3 mo. LIBOR US + 0.730%), 3.56%, 04/23/24(j)			3,340		3,482,965
(3 mo. LIBOR US + 0.890%), 3.80%, 07/23/24(j)			14,168		14,942,602
3.88%, 09/10/24			1,785		1,899,284
(3 mo. LIBOR US + 1.000%), 4.02%, 12/05/24(j)			21,937		23,390,706
3.13%, 01/23/25			1,555		1,610,139
(3 mo. LIBOR US + 1.155%), 3.22%, 03/01/25(j)			86		89,039
3.90%, 07/15/25			169		182,210
(Secured Overnight Financing Rate + 1.160%), 2.30%, 10/15/25(j)			6,600		6,575,044
3.20%, 06/15/26			370		384,111
4.13%, 12/15/26			233		254,234
(3 mo. LIBOR US + 1.245%), 3.96%, 01/29/27(j)			365		394,659
4.25%, 10/01/27			640		703,127
(3 mo. LIBOR US + 1.337%), 3.78%, 02/01/28(j)			29,607		31,675,958
(3 mo. LIBOR US + 1.380%), 3.54%, 05/01/28(j)			31,677		33,402,238
(3 mo. LIBOR US + 0.945%), 3.51%, 01/23/29(j)			2,232		2,359,310
(3 mo. LIBOR US + 1.260%), 4.20%, 07/23/29(j)			4,566		5,060,486
(3 mo. LIBOR US + 1.160%), 3.70%, 05/06/30(j)			1,126		1,206,498
(Secured Overnight Financing Rate + 1.510%), 2.74%, 10/15/30(j)			15,455		15,346,442
(3 mo. LIBOR US + 1.360%), 3.88%, 07/24/38(j)			2,282		2,521,275
(3 mo. LIBOR US + 1.460%), 4.03%, 07/24/48(j)			58		65,572
Kasikornbank PCL, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 1.700%), 3.34%, 10/02/31(j)			1,740		1,727,154
KeyBank NA:
3.35%, 06/15/21			1,500		1,530,179
2.30%, 09/14/22			745		748,932
Keycorp, 4.15%, 10/29/25			1,241		1,358,013
Lloyds Banking Group PLC:
4.45%, 05/08/25			3,220		3,465,410
3.75%, 01/11/27			5,349		5,547,378
Mitsubishi UFJ Financial Group, Inc.:
3.54%, 07/26/21			1,810		1,850,734
3.00%, 02/22/22			3,776		3,843,168
2.67%, 07/25/22			140		141,446
3.46%, 03/02/23			28,535		29,559,402
3.76%, 07/26/23			8,920		9,377,202
3.41%, 03/07/24			30		31,232
3.85%, 03/01/26			941		1,009,805
3.29%, 07/25/27			477		498,400
3.20%, 07/18/29			770		795,637

Security		Par (000)		Value
Banks (continued)
Mizuho Financial Group, Inc.:
2.63%, 04/12/21(b)	USD		7,250	$	7,280,913
2.27%, 09/13/21			5,639		5,635,524
2.95%, 02/28/22			32,190		32,650,839
(3 mo. LIBOR US + 0.980%), 2.84%, 07/16/25(j)			797		805,573
(3 mo. LIBOR US + 1.100%), 2.56%, 09/13/25(j)			9,080		9,055,069
3.66%, 02/28/27			352		377,139
(3 mo. LIBOR US + 1.310%), 2.87%, 09/13/30(j)			4,826		4,805,775
Nordea Bank Abp, 2.13%, 05/29/20(b)			9,883		9,887,328
Royal Bank of Scotland Group PLC:
(3 mo. LIBOR US + 1.480%), 3.50%, 05/15/23(j)			1,875		1,899,956
(3 mo. LIBOR US + 1.550%), 4.52%, 06/25/24(j)			884		929,645
Samba Funding Ltd., 2.75%, 10/02/24			1,800		1,787,850
Santander UK Group Holdings PLC, 2.88%, 08/05/21			12,877		12,922,997
Santander UK PLC, 5.00%, 11/07/23(b)			18,713		19,870,589
Shinhan Financial Group Co. Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 1.500%), 3.34%, 02/05/30(j)			1,025		1,038,224
Shizuoka Bank Ltd., (3 mo. LIBOR US - 0.500%), 1.78%, 01/25/23(a)(g)			200		189,714
Societe Generale SA, 0.75%, 05/26/23	EUR		5,000		5,609,077
Standard Chartered PLC:
(3 mo. LIBOR US + 1.150%), 4.25%, 01/20/23(b)(j)	USD		18,430		19,054,758
(3 mo. LIBOR US + 1.080%), 3.89%, 03/15/24(b)(j)			4,755		4,908,573
Sumitomo Mitsui Financial Group, Inc.:
2.70%, 07/16/24			4,400		4,449,090
3.04%, 07/16/29			2,780		2,843,607
SunTrust Bank:
2.80%, 05/17/22			4,550		4,629,190
3.20%, 04/01/24			78		81,087
Svenska Handelsbanken AB, 3.35%, 05/24/21			3,000		3,062,883
Toronto-Dominion Bank:
3.50%, 07/19/23			2,658		2,802,923
3.25%, 03/11/24			50		52,254
0.38%, 04/25/24	EUR		4,950		5,456,951
2.65%, 06/12/24	USD		2,502		2,549,164
U.S. Bancorp, 2.95%, 07/15/22			4,709		4,818,366
U.S. Bank NA, (3 mo. LIBOR US + 0.290%), 3.10%, 05/21/21(j)			3,410		3,431,140
US Bancorp:
2.40%, 07/30/24			7,609		7,706,839
3.15%, 04/27/27			187		198,196
Volkswagen Bank GmbH, 0.38%, 07/05/22	EUR		3,800		4,151,773
Washington Mutual Escrow Bonds:
0.00%(c)(f)(i)(k)	USD		2,570		—
0.00%(c)(f)(i)(k)			3,115		—
0.00%(c)(f)(i)(k)			11,911		1
0.00%(c)(f)(i)(k)			13,308		1
Wells Fargo & Co.:
2.60%, 07/22/20			4,233		4,252,982
2.55%, 12/07/20			4,636		4,660,879
3.00%, 01/22/21			80		80,884
2.50%, 03/04/21			15,980		16,055,019
4.60%, 04/01/21			4,396		4,556,239
2.10%, 07/26/21			617		616,378
3.50%, 03/08/22			6,866		7,084,825
2.63%, 07/22/22			14,612		14,774,230
3.75%, 01/24/24			19,263		20,382,947
3.30%, 09/09/24			970		1,012,608
3.00%, 02/19/25			1,100		1,128,051

42 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Banks (continued)
Wells Fargo & Co.: (continued)
3.55%, 09/29/25	USD		1,284	$	1,357,027
3.00%, 04/22/26			6,321		6,481,284
3.00%, 10/23/26			2,228		2,288,130
(3 mo. LIBOR US + 1.170%), 3.20%, 06/17/27(j)			1,209		1,249,232
(3 mo. LIBOR US + 1.310%), 3.58%, 05/22/28(j)			23,712		25,119,890
4.15%, 01/24/29			2,566		2,845,131
Wells Fargo Bank NA:
(3 mo. LIBOR US + 0.490%), 3.33%, 07/23/21(j)			13,250		13,366,883
3.55%, 08/14/23			2,040		2,141,940
Woori Bank, 5.13%, 08/06/28			600		682,773
Yamaguchi Financial Group, Inc., (3 mo. LIBOR US - 0.500%), 1.61%, 03/26/20(a)(g)			1,000		977,042
					1,158,205,484
Beverages — 0.6%
Anheuser-Busch Cos. LLC/Anheuser-Busch InBev Worldwide, Inc.:
4.70%, 02/01/36			29,211		33,741,568
4.90%, 02/01/46			6,312		7,531,649
Anheuser-Busch InBev Worldwide, Inc.:
4.00%, 04/13/28			57		62,864
4.75%, 01/23/29			26,725		31,061,433
4.95%, 01/15/42			500		589,767
Coca-Cola Co.:
2.20%, 05/25/22			331		333,720
3.20%, 11/01/23			17		17,879
2.88%, 10/27/25			1,599		1,673,345
2.25%, 09/01/26			1,840		1,849,736
Coca-Cola European Partners PLC, 1.88%, 03/18/30	EUR		2,150		2,636,888
Keurig Dr Pepper, Inc.:
3.55%, 05/25/21	USD		2,577		2,632,081
4.06%, 05/25/23			294		310,919
3.43%, 06/15/27			318		328,054
Molson Coors Brewing Co.:
5.00%, 05/01/42			190		209,842
4.20%, 07/15/46			1,710		1,727,993
PepsiCo, Inc.:
3.45%, 10/06/46			3,905		4,208,458
4.00%, 05/02/47			2,861		3,350,701
PepsiCo., Inc., 4.45%, 04/14/46			1,227		1,528,576
					93,795,473
Biotechnology — 0.5%
AbbVie, Inc.:
3.60%, 05/14/25			1,710		1,778,547
4.50%, 05/14/35			13,962		14,962,050
4.70%, 05/14/45			91		97,349
Amgen, Inc.:
4.40%, 05/01/45			8,673		9,801,223
4.66%, 06/15/51			461		539,751
Baxalta, Inc., 5.25%, 06/23/45			923		1,193,705
Celgene Corp.:
3.95%, 10/15/20			840		854,836
2.25%, 08/15/21			470		470,019
3.25%, 08/15/22			4,110		4,234,647
3.55%, 08/15/22			3,980		4,127,616
2.75%, 02/15/23			5,783		5,886,114
3.25%, 02/20/23			12,189		12,618,251
3.63%, 05/15/24			48		50,688
Gilead Sciences, Inc.:
3.50%, 02/01/25			8,217		8,675,297
3.65%, 03/01/26			945		1,012,876
4.60%, 09/01/35			4,174		4,948,381
4.80%, 04/01/44			2,377		2,842,800

Security		Par (000)		Value
Biotechnology (continued)
Gilead Sciences, Inc.: (continued)
4.50%, 02/01/45	USD		630	$	729,062
4.75%, 03/01/46			324		385,640
					75,208,852
Building Products — 0.1%
Johnson Controls International PLC:
4.63%, 07/02/44			1,950		2,119,742
5.13%, 09/14/45			107		124,852
4.50%, 02/15/47			57		62,836
LIXIL Group Corp.:
0.00%, 03/04/20(g)(h)	JPY		80,000		730,847
0.00%, 03/04/22(g)(h)			30,000		269,605
Masonite International Corp., 5.75%, 09/15/26(b)	USD		120		126,600
Owens Corning:
3.95%, 08/15/29			1,900		1,931,864
4.30%, 07/15/47			259		235,209
Sika Capital BV, 0.88%, 04/29/27	EUR		3,000		3,411,780
					9,013,335
Capital Markets — 2.0%
Bank of New York Mellon Corp.:
(3 mo. LIBOR US + 0.634%), 2.66%, 05/16/23(j)	USD		763		772,917
3.65%, 02/04/24			134		142,193
2.80%, 05/04/26			1,534		1,575,439
(3 mo. LIBOR US + 1.069%), 3.44%, 02/07/28(j)			5,665		6,006,943
CCTI 2017 Ltd., 3.63%, 08/08/22			1,675		1,657,203
Charles Schwab Corp., 3.20%, 03/02/27			3,391		3,548,817
Cindai Capital Ltd., 0.00%, 02/08/23(g)(h)			2,461		2,381,379
CME Group, Inc.:
3.00%, 09/15/22			255		263,159
3.75%, 06/15/28			1,760		1,966,723
Credit Suisse Group AG:
(3 mo. LIBOR US + 1.200%), 3.00%, 12/14/23(b)(j)			15,500		15,656,431
(3 mo. LIBOR US + 1.240%), 4.21%, 06/12/24(b)(j)			11,965		12,599,423
Credit Suisse Group Funding Guernsey Ltd.:
3.45%, 04/16/21			1,328		1,349,877
3.80%, 06/09/23			1,710		1,785,885
3.75%, 03/26/25			790		829,712
Deutsche Bank AG:
2.70%, 07/13/20			12,042		12,017,350
2.95%, 08/20/20			925		924,626
4.25%, 02/04/21			2,930		2,962,730
4.25%, 10/14/21			3,652		3,709,962
Goldman Sachs Group, Inc.:
2.55%, 10/23/19			17,220		17,222,076
2.75%, 09/15/20			2,492		2,505,389
5.25%, 07/27/21			81		85,364
2.35%, 11/15/21			14,988		15,003,737
5.75%, 01/24/22			1,691		1,821,869
(3 mo. LIBOR US + 1.053%), 2.91%, 06/05/23(j)			668		676,638
(3 mo. LIBOR US + 0.990%), 2.91%, 07/24/23(j)			193		195,592
3.75%, 05/22/25			340		359,801
3.75%, 02/25/26			20		21,151
(3 mo. LIBOR US + 1.170%), 3.33%, 05/15/26(a)			10,315		10,368,005
3.50%, 11/16/26			900		934,964
3.85%, 01/26/27			9,801		10,392,701
(3 mo. LIBOR US + 1.510%), 3.69%, 06/05/28(j)			15,287		16,034,753

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 43

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Capital Markets (continued)
Goldman Sachs Group, Inc.: (continued)
(3 mo. LIBOR US + 1.158%), 3.81%, 04/23/29(j)	USD		2,608	$	2,768,937
(3 mo. LIBOR US + 1.301%), 4.22%, 05/01/29(j)			2,770		3,023,704
(3 mo. LIBOR US + 1.373%), 4.02%, 10/31/38(j)			4,160		4,479,361
(3 mo. LIBOR US + 1.430%), 4.41%, 04/23/39(j)			135		152,471
Intercontinental Exchange, Inc.:
4.00%, 10/15/23			1,000		1,067,262
3.75%, 12/01/25			6,634		7,141,819
3.10%, 09/15/27			1,680		1,759,593
3.75%, 09/21/28			6,270		6,868,453
4.25%, 09/21/48			330		391,768
Lehman Brothers Holdings, Inc., 6.75%, 12/28/17(c)(f)(i)			7,360		1
Moody’s Corp.:
2.75%, 12/15/21			411		416,442
4.88%, 02/15/24			608		669,906
Morgan Stanley:
3.13%, 01/23/23			178		182,581
3.75%, 02/25/23			13,503		14,117,944
4.00%, 07/23/25			230		248,119
3.13%, 07/27/26			260		267,957
6.25%, 08/09/26			5,612		6,804,333
3.63%, 01/20/27			26,090		27,625,230
(3 mo. LIBOR US + 1.340%), 3.59%, 07/22/28(j)			20,468		21,576,847
(3 mo. LIBOR US + 1.140%), 3.77%, 01/24/29(j)			14,783		15,799,742
Northern Trust Corp.:
3.15%, 05/03/29			419		443,367
(3 mo. LIBOR US + 1.131%), 3.38%, 05/08/32(j)			4,895		5,023,592
Nuveen LLC, 4.00%, 11/01/28(b)			421		470,172
Poseidon Finance 1 Ltd., 0.00%, 02/01/25(g)(h)			2,640		2,614,267
State Street Corp.:
3.55%, 08/18/25			99		106,045
2.65%, 05/19/26			3,056		3,134,458
(3 mo. LIBOR US + 1.030%), 4.14%, 12/03/29(j)			461		520,387
UBS Group AG, (3 mo. LIBOR US + 1.468%), 3.13%, 08/13/30(b)(j)			3,857		3,883,277
UBS Group Funding Switzerland AG:
2.65%, 02/01/22(b)			334		336,832
3.49%, 05/23/23(b)			3,000		3,079,514
(3 mo. LIBOR US + 0.954%), 2.86%, 08/15/23(b)(j)			14,300		14,454,263
4.13%, 09/24/25(b)			9,064		9,792,452
4.25%, 03/23/28(b)			1,726		1,882,668
					306,876,573
Chemicals — 0.4%
Air Liquide Finance SA, 2.50%, 09/27/26(b)			1,050		1,060,232
BASF SE, 2.00%, 12/05/22	EUR		7,460		8,680,976
Cydsa SAB de CV, 6.25%, 10/04/27(b)	USD		2,415		2,454,998
Dow Chemical Co.:
9.00%, 04/01/21			3,960		4,322,919
4.13%, 11/15/21			136		140,947
4.55%, 11/30/25(b)			2,012		2,210,133
3.63%, 05/15/26(b)			6,554		6,840,804
4.80%, 11/30/28(b)			515		581,785
4.38%, 11/15/42			6,397		6,640,432
DuPont de Nemours, Inc.:
4.21%, 11/15/23			97		103,947
4.49%, 11/15/25			17,561		19,406,896
5.42%, 11/15/48			6,752		8,548,287
Kansai Paint Co. Ltd., 0.00%, 06/17/22(g)(h)	JPY		80,000		778,802

Security		Par (000)		Value
Chemicals (continued)
LG Chem Ltd., 0.00%, 04/16/21(g)(h)	EUR		300	$	324,125
Mitsubishi Chemical Holdings Corp.:
0.00%, 03/30/22(g)(h)	JPY		150,000		1,390,204
0.00%, 03/29/24(g)(h)			40,000		372,621
Rock International Investment, Inc., 6.63%, 03/27/20	USD		500		372,225
RPM International, Inc., 4.25%, 01/15/48			679		662,755
Sherwin-Williams Co.:
4.00%, 12/15/42			971		1,005,356
4.50%, 06/01/47			1,391		1,558,782
UPL Corp. Ltd., 4.50%, 03/08/28			1,040		1,078,192
					68,535,418
Commercial Services & Supplies — 0.2%
Beijing Environment Bvi Co. Ltd., 5.30%, 10/18/21			680		701,463
Conservation Fund, 3.47%, 12/15/29			2,533		2,576,140
Republic Services, Inc.:
3.55%, 06/01/22			2,050		2,123,923
4.75%, 05/15/23			5,974		6,470,532
2.90%, 07/01/26			2,994		3,080,478
3.95%, 05/15/28			5,737		6,347,858
Waste Management, Inc.:
3.13%, 03/01/25			1,035		1,085,419
3.90%, 03/01/35			1,676		1,848,242
4.00%, 07/15/39			6,465		7,343,091
4.15%, 07/15/49			4,100		4,777,897
					36,355,043
Communications Equipment — 0.1%
Cisco Systems, Inc., 2.95%, 02/28/26			309		325,494
Motorola Solutions, Inc., 4.60%, 05/23/29			10,200		11,115,579
					11,441,073
Construction & Engineering — 0.0%
China City Construction International Co. Ltd., 5.35%, 07/03/17(f)(i)	CNH		340		1,546
China Singyes Solar Technologies Holdings Ltd., 7.95%, 02/15/19(f)(i)	USD		350		287,070
Great Lakes Dredge & Dock Corp., 8.00%, 05/15/22			2,048		2,182,758
IHS Netherlands Holdco BV:
7.13%, 03/18/25(b)			1,509		1,534,578
8.00%, 09/18/27(b)			2,135		2,178,234
Shimizu Corp., 0.00%, 10/16/20(g)(h)	JPY		50,000		465,896
Zhengzhou Real Estate Group Co. Ltd., 3.95%, 10/09/22	USD		965		964,963
					7,615,045
Construction Materials — 0.0%
Cemex SAB de CV, 3.72%, 03/15/20(g)			593		590,331
Summit Materials LLC/Summit Materials Finance Corp., 6.13%, 07/15/23			134		136,345
					726,676
Consumer Finance — 1.0%
American Express Co.:
2.50%, 08/01/22			2,604		2,630,140
3.70%, 08/03/23			6,277		6,613,221
2.50%, 07/30/24			240		241,856
4.20%, 11/06/25			3,624		3,982,556
3.13%, 05/20/26			11,205		11,647,574
American Express Credit Corp.:
2.38%, 05/26/20			563		563,734
2.60%, 09/14/20			48		48,247
2.25%, 05/05/21			3,441		3,453,206
2.70%, 03/03/22			437		444,614
American Honda Finance Corp., 2.15%, 09/10/24			4,500		4,480,792

44 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Consumer Finance (continued)
Capital One Financial Corp.:
3.45%, 04/30/21	USD		1,162	$	1,183,045
4.75%, 07/15/21			719		750,714
3.20%, 01/30/23			940		964,689
3.90%, 01/29/24			12,656		13,371,099
3.30%, 10/30/24			125		129,376
4.25%, 04/30/25			3,691		3,994,276
3.75%, 03/09/27			3,676		3,858,684
3.80%, 01/31/28			748		789,130
Credivalores-Crediservicios SAS, 9.75%, 07/27/22(b)			1,482		1,473,664
Discover Financial Services, 4.10%, 02/09/27			1,762		1,874,898
Ford Motor Credit Co. LLC:
2.43%, 06/12/20			2,180		2,174,550
3.16%, 08/04/20			2,130		2,135,296
3.20%, 01/15/21			2,396		2,399,203
5.75%, 02/01/21			7,810		8,074,094
3.34%, 03/18/21			1,500		1,507,006
5.88%, 08/02/21			200		209,490
3.22%, 01/09/22			31,157		31,125,419
3.34%, 03/28/22			2,303		2,306,030
2.98%, 08/03/22			6,575		6,520,906
5.58%, 03/18/24			1,894		2,013,454
4.69%, 06/09/25			925		943,547
4.13%, 08/04/25			1,907		1,886,712
4.39%, 01/08/26			1,078		1,072,775
5.11%, 05/03/29			209		210,127
General Motors Financial Co., Inc.:
4.20%, 11/06/21			724		746,919
3.55%, 07/08/22			120		122,456
4.00%, 01/15/25			11,830		12,145,476
4.35%, 04/09/25			210		218,746
4.00%, 10/06/26			1,389		1,405,509
Hyundai Capital Services, Inc., 3.00%, 08/29/22(b)			7,790		7,850,859
Synchrony Financial:
2.70%, 02/03/20			1,986		1,988,255
4.38%, 03/19/24			3,303		3,504,905
4.25%, 08/15/24			570		600,826
4.50%, 07/23/25			133		141,936
3.70%, 08/04/26			4		4,083
Tarjeta Naranja SA, (30 to 35 Days Argentina Deposit Rates Badlar Private Banks + 3.500%), 51.58%, 04/11/22(a)(b)			3,141		507,642
Toyota Motor Credit Corp.:
3.35%, 01/08/24			75		79,050
3.05%, 01/11/28			3,390		3,580,943
3.65%, 01/08/29			1,684		1,864,732
Unifin Financiera SAB de CV SOFOM ENR, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 6.308%), 8.88%(b)(j)(k)			2,052		1,811,531
					161,647,992
Containers & Packaging — 0.1%
Ardagh Packaging Finance PLC/Ardagh Holdings USA, Inc., 4.25%, 09/15/22(b)			336		340,361
Graphic Packaging International LLC, 4.75%, 04/15/21			104		107,380
International Paper Co.:
5.00%, 09/15/35			245		284,922
6.00%, 11/15/41			4,020		4,905,898
4.40%, 08/15/47			79		82,227
Klabin Finance SA, 4.88%, 09/19/27(b)			3,015		3,049,861
Reynolds Group Issuer, Inc./Reynolds Group Issuer LLC/Reynolds Group Issuer Luxembourg, 7.00%, 07/15/24(b)			155		160,619
					8,931,268

Security		Par (000)		Value
Diversified Consumer Services — 0.1%
American University, 3.67%, 04/01/49	USD		6,416	$	7,073,229
China Education Group Holdings Ltd., 2.00%, 03/28/24(g)	HKD		8,000		1,083,226
George Washington University, 4.13%, 09/15/48	USD		3,257		3,887,316
Massachusetts Institute of Technology, 3.96%, 07/01/38			1,385		1,615,568
University of Southern California, 3.03%, 10/01/39			366		377,054
Wesleyan University, 4.78%, 07/01/2116			1,285		1,539,517
					15,575,910
Diversified Financial Services — 1.3%
AXA Equitable Holdings, Inc.:
3.90%, 04/20/23			880		918,489
5.00%, 04/20/48			1,640		1,767,776
Azul Investments LLP, 5.88%, 10/26/24(b)			234		233,561
Banque Federative du Credit Mutuel SA:
0.13%, 02/05/24	EUR		4,100		4,487,133
0.75%, 06/08/26			700		789,461
Baoxin Auto Finance I Ltd., (3 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 8.909%), 5.63%(j)(k)	USD		500		406,563
BAT International Finance PLC:
3.95%, 06/15/25(b)			12,755		13,278,198
3.13%, 03/06/29	EUR		4,527		5,545,986
BHP Billiton Finance USA Ltd.:
4.13%, 02/24/42	USD		1,179		1,357,698
5.00%, 09/30/43			1,571		2,028,220
Capitol Investment Merger Sub 2 LLC, 10.00%, 08/01/24(b)			2,287		2,372,762
CC Holdings GS V LLC/Crown Castle GS III Corp., 3.85%, 04/15/23			2,211		2,317,360
CK Hutchison International 17 II Ltd., 3.25%, 09/29/27			600		617,812
Coastal Emerald Ltd.:
(5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 7.445%), 4.30%(j)(k)			1,190		1,188,217
3.95%, 08/01/22			695		698,475
Deutsche Telekom International Finance BV, 3.60%, 01/19/27(b)			3,890		4,107,512
Easy Tactic Ltd.:
8.63%, 02/27/24			630		604,800
8.13%, 07/11/24			800		750,848
Energuate Trust, 5.88%, 05/03/27(b)			547		547,684
GE Capital International Funding Co. Unlimited Co., 4.42%, 11/15/35			8,729		9,135,062
GlaxoSmithKline Capital PLC, 3.38%, 06/01/29			5,651		6,063,424
GlaxoSmithKline Capital, Inc., 3.88%, 05/15/28			3,223		3,556,879
Greenko Mauritius Ltd., 6.25%, 02/21/23			900		913,500
Guojing Capital BVI Ltd., 3.95%, 12/11/22			498		497,378
Holcim U.S. Finance Sarl & Cie SCS, 5.15%, 09/12/23(b)			3,645		3,917,076
Hyundai Capital America:
2.55%, 04/03/20(b)			21,316		21,362,629
3.95%, 02/01/22(b)			11,376		11,681,901
IBM Credit LLC, 3.45%, 11/30/20			4,770		4,853,185
Intelsat Jackson Holdings SA:
5.50%, 08/01/23			2,174		2,028,125
8.00%, 02/15/24(b)			155		161,006
8.50%, 10/15/24(b)			1,808		1,821,000
InterCorp. Peru Ltd., 3.88%, 08/15/29(b)			789		792,945
Merck Financial Services GmbH:
0.01%, 12/15/23	EUR		10,600		11,578,813
0.88%, 07/05/31			1,500		1,685,614
New Lion Bridge Co. Ltd., 9.75%, 10/10/20	USD		430		384,313

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 45

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Diversified Financial Services (continued)
ORIX Corp., 2.90%, 07/18/22	USD		4,177	$	4,247,287
Pacific National Finance Pty Ltd., 4.75%, 03/22/28			1,100		1,153,557
Pearl Holding III Ltd., 9.50%, 12/11/22			600		435,000
Prime Bloom Holdings Ltd., 6.95%, 07/05/22			890		592,015
RELX Capital, Inc.:
3.50%, 03/16/23			6,730		6,972,189
1.30%, 05/12/25	EUR		4,085		4,720,651
4.00%, 03/18/29	USD		6,770		7,389,266
Santos Finance Ltd., 5.25%, 03/13/29			1,500		1,621,703
Shell International Finance BV:
2.25%, 01/06/23			900		909,050
3.25%, 05/11/25			3,000		3,173,921
1.25%, 05/12/28	EUR		2,550		3,031,379
4.13%, 05/11/35	USD		7,771		8,980,658
6.38%, 12/15/38			1,561		2,281,788
3.63%, 08/21/42			2,076		2,234,483
4.55%, 08/12/43			1,125		1,383,306
3.75%, 09/12/46			3		3,327
Siemens Financieringsmaatschappij NV:
0.00%, 09/05/21	EUR		5,070		5,550,668
0.13%, 09/05/29			1,110		1,187,193
1.38%, 09/06/30			200		240,016
1.25%, 02/28/31			4,670		5,538,776
0.50%, 09/05/34			1,020		1,087,274
Silversea Cruise Finance Ltd., 7.25%, 02/01/25(b)	USD		2,647		2,826,996
Total Capital International SA:
2.75%, 06/19/21			380		384,880
2.88%, 02/17/22			370		378,342
3.70%, 01/15/24			21		22,408
3.75%, 04/10/24			140		149,966
2.43%, 01/10/25			2,110		2,133,739
1.38%, 10/04/29	EUR		2,200		2,665,542
Volvo Treasury AB, (3 mo. EURIBOR + 0.650%), 0.22%, 09/13/21(a)			1,600		1,755,140
Woodside Finance Ltd., 3.65%, 03/05/25(b)	USD		562		579,237
					198,081,162
Diversified Telecommunication Services — 1.5%
AT&T Inc.:
3.20%, 03/01/22			2,658		2,722,826
3.40%, 06/15/22			116		119,574
0.00%, 11/27/22(b)(h)			18,000		16,661,750
3.60%, 07/15/25			2,168		2,282,197
3.80%, 02/15/27			1,895		2,005,542
4.10%, 02/15/28			23		24,864
4.35%, 03/01/29			114		125,912
4.30%, 02/15/30			27,163		29,886,848
4.50%, 05/15/35			6,227		6,832,209
5.25%, 03/01/37			130		152,999
6.00%, 08/15/40			8,417		10,496,386
5.35%, 09/01/40			420		492,109
6.38%, 03/01/41			699		899,912
5.55%, 08/15/41			295		352,636
5.15%, 03/15/42			2,277		2,609,171
4.30%, 12/15/42			591		616,724
4.65%, 06/01/44			689		742,528
4.80%, 06/15/44			3,085		3,412,457
4.35%, 06/15/45			10,368		10,895,272
4.85%, 07/15/45			4,435		4,946,878
4.75%, 05/15/46			1,091		1,209,882
5.15%, 11/15/46			2,197		2,538,598
5.45%, 03/01/47			1,393		1,685,172
C&W Senior Financing DAC, 6.88%, 09/15/27(b)			3,437		3,561,591
Connect Finco SARL/Connect U.S. Finco LLC, 6.75%, 10/01/26(b)			2,788		2,840,275
Empresa Nacional de Telecomunicaciones SA, 4.75%, 08/01/26(b)			1,285		1,354,470

Security		Par (000)		Value
Diversified Telecommunication Services (continued)
Intelsat SA, 4.50%, 06/15/25(g)	USD		3,270	$	4,801,037
Level 3 Financing, Inc.:
5.38%, 08/15/22			1,419		1,426,982
5.63%, 02/01/23			2,376		2,405,700
Oi SA, 10.00% (10.00% Cash or 12.00% PIK), 07/27/25(l)			4,532		4,152,445
Orange SA:
1.20%, 07/11/34	EUR		2,700		3,096,376
1.38%, 09/04/49			300		310,512
Telefonica del Peru SAA, 7.38%, 04/10/27(b)	PEN		4,500		1,415,304
Verizon Communications, Inc.:
3.38%, 02/15/25	USD		674		710,980
4.13%, 03/16/27			45,463		50,199,083
4.50%, 08/10/33			10,648		12,363,827
4.40%, 11/01/34			2,201		2,517,821
4.27%, 01/15/36			30,080		33,823,325
5.25%, 03/16/37			1,994		2,468,696
4.81%, 03/15/39			2,493		2,987,994
4.75%, 11/01/41			423		501,683
					232,650,547
Electric Utilities — 2.1%
Adani Transmission Ltd., 4.00%, 08/03/26			662		676,688
AEP Texas, Inc.:
3.95%, 06/01/28			9,781		10,797,539
4.15%, 05/01/49			93		107,015
AEP Transmission Co. LLC:
4.25%, 09/15/48			2,195		2,582,386
3.80%, 06/15/49			40		43,987
3.15%, 09/15/49			1,870		1,839,546
Alabama Power Co.:
3.55%, 12/01/23			885		935,404
4.15%, 08/15/44			310		351,680
3.75%, 03/01/45			5,240		5,647,771
Series A, 4.30%, 07/15/48			2,597		3,036,011
3.45%, 10/01/49			3,110		3,207,488
Baltimore Gas & Electric Co.:
3.50%, 08/15/46			4,197		4,357,716
3.75%, 08/15/47			2,530		2,730,994
4.25%, 09/15/48			1,490		1,736,796
3.20%, 09/15/49			1,480		1,464,389
Bi Hai Co. Ltd., 6.25%, 03/05/22			400		412,375
CenterPoint Energy Houston Electric LLC:
3.55%, 08/01/42			2,240		2,398,862
3.95%, 03/01/48			549		626,463
Commonwealth Edison Co., 2.95%, 08/15/27			1,200		1,242,677
Dayton Power & Light Co., 3.95%, 06/15/49(b)			4,358		4,785,302
DTE Electric Co., 4.05%, 05/15/48			6,670		7,734,423
Duke Energy Carolinas LLC:
3.05%, 03/15/23			1,085		1,122,593
3.95%, 11/15/28			1,701		1,898,941
2.45%, 08/15/29			5,675		5,679,234
5.30%, 02/15/40			444		575,587
4.25%, 12/15/41			483		557,062
4.00%, 09/30/42			1,150		1,286,808
3.88%, 03/15/46			1,550		1,720,844
3.70%, 12/01/47			3,510		3,810,520
3.95%, 03/15/48			856		964,330
3.20%, 08/15/49			2,905		2,912,874
Duke Energy Florida LLC:
3.80%, 07/15/28			2,807		3,092,144
6.40%, 06/15/38			3,550		5,213,676
3.40%, 10/01/46			2,103		2,171,796
4.20%, 07/15/48			6		6,983
Duke Energy Ohio, Inc., 3.65%, 02/01/29			10,000		10,941,123
Duke Energy Progress LLC:
3.00%, 09/15/21			1,710		1,741,688
3.25%, 08/15/25			4,025		4,245,190
3.70%, 09/01/28			10,090		11,074,838
3.45%, 03/15/29			599		646,507

46 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security			Par (000)		Value
Electric Utilities (continued)
Duke Energy Progress LLC: (continued)
4.10%, 05/15/42	USD			2,622	$	2,985,603
4.10%, 03/15/43				2,545		2,872,263
4.38%, 03/30/44				625		737,465
3.70%, 10/15/46				49		52,642
Entergy Arkansas LLC, 4.20%, 04/01/49				164		189,836
Entergy Corp., 2.95%, 09/01/26				521		529,058
Entergy Louisiana LLC:
5.40%, 11/01/24				1,470		1,701,370
4.20%, 09/01/48				5,580		6,537,150
4.20%, 04/01/50				10		11,755
Eversource Energy, 2.90%, 10/01/24				6,724		6,889,054
Exelon Corp.:
4.95%, 06/15/35				700		819,348
4.45%, 04/15/46				2,155		2,436,676
FirstEnergy Transmission LLC:
4.35%, 01/15/25(b)				13,860		14,952,336
4.55%, 04/01/49(b)				4,200		4,940,573
Florida Power & Light Co.:
(3 mo. LIBOR US + 0.400%), 2.64%, 05/06/22(a)				26,545		26,552,292
3.25%, 06/01/24				60		62,988
3.70%, 12/01/47				81		89,803
3.95%, 03/01/48				5,658		6,540,665
3.15%, 10/01/49				5,810		5,911,841
Generacion Mediterranea SA/Generacion Frias SA/Central Termica Roca SA, 9.63%, 07/27/23(b)				4,333		2,274,825
Huachen Energy Co. Ltd., 6.63%, 05/18/20				400		231,375
Indiana Michigan Power Co.:
4.55%, 03/15/46				366		442,662
3.75%, 07/01/47				684		742,548
4.25%, 08/15/48				195		230,078
Interstate Power & Light Co.:
3.60%, 04/01/29				112		120,102
3.50%, 09/30/49				395		396,919
ITC Holdings Corp., 2.70%, 11/15/22				3,406		3,438,764
Kansas City Power & Light Co., 4.20%, 03/15/48				6,533		7,650,880
LLPL Capital Pte Ltd., 6.88%, 02/04/39				642		743,270
MidAmerican Energy Co.:
4.40%, 10/15/44				2,689		3,224,789
3.65%, 08/01/48				1,020		1,111,734
Mid-Atlantic Interstate Transmission LLC, 4.10%, 05/15/28(b)				1,152		1,269,989
Mong Duong Finance Holdings BV, 5.13%, 05/07/29				1,175		1,188,219
Northern States Power Co.:
3.40%, 08/15/42				4,300		4,503,679
4.00%, 08/15/45				1,610		1,838,678
3.60%, 09/15/47				855		928,110
4.20%, 09/01/48				2,160		2,480,014
2.90%, 03/01/50				1,945		1,880,390
NSTAR Electric Co.:
3.20%, 05/15/27				2,007		2,112,486
3.25%, 05/15/29				825		879,727
Ohio Power Co.:
Series G, 6.60%, 02/15/33				3,415		4,735,084
4.00%, 06/01/49				2,719		3,092,143
Oklahoma Gas & Electric Co., 3.30%, 03/15/30 .				9,325		9,706,831
Oncor Electric Delivery Co. LLC:		��
3.70%, 11/15/28(b)				5,350		5,890,990
5.75%, 03/15/29				480		607,456
4.55%, 12/01/41				1,621		1,977,695
3.80%, 09/30/47				2,227		2,465,460
4.10%, 11/15/48				169		198,976
3.80%, 06/01/49(b)				997		1,117,783

Security		Par (000)		Value
Electric Utilities (continued)
Oncor Electric Delivery Co. LLC: (continued)
3.10%, 09/15/49(b)	USD		2,220	$	2,224,559
Pacificorp:
4.10%, 02/01/42			5,963		6,789,611
4.13%, 01/15/49			2,385		2,765,064
Public Service Electric & Gas Co.:
2.38%, 05/15/23			990		1,002,494
3.65%, 09/01/28			6,843		7,496,137
3.20%, 05/15/29			321		341,233
Southern Co. Gas Capital Corp., 3.95%, 10/01/46			310		325,443
Southwestern Electric Power Co., 4.10%, 09/15/28			2,574		2,851,871
Southwestern Public Service Co.:
4.50%, 08/15/41			147		172,994
3.40%, 08/15/46			338		348,250
3.75%, 06/15/49			6		6,617
Tampa Electric Co.:
4.35%, 05/15/44			1,250		1,458,446
4.30%, 06/15/48			1,017		1,189,439
4.45%, 06/15/49			2,741		3,308,568
Tohoku Electric Power Co., Inc., 0.00%, 12/03/20(g)(h)	JPY		110,000		1,004,382
Trans-Allegheny Interstate Line Co., 3.85%, 06/01/25(b)	USD		8,407		8,936,538
Union Electric Co., 3.50%, 03/15/29			3,760		4,086,253
Vistra Operations Co. LLC:
3.55%, 07/15/24(b)			5,420		5,455,974
5.00%, 07/31/27(b)			2,527		2,602,001
4.30%, 07/15/29(b)			8,908		9,139,674
					330,178,172
Electrical Equipment — 0.2%
Bizlink Holding, Inc., 0.00%, 02/01/23(g)(h)			750		790,843
Eaton Capital Unlimited Co.:
0.02%, 05/14/21	EUR		7,480		8,167,644
0.70%, 05/14/25			3,085		3,426,732
Schneider Electric SE, 0.25%, 09/09/24			12,700		14,037,701
Suzlon Energy Ltd., 5.75%, 07/16/19(e)(f)(g)(i)	USD		500		150,000
					26,572,920
Electronic Equipment, Instruments & Components — 0.0%
Amphenol Corp., 3.20%, 04/01/24			1,816		1,872,470
Corning, Inc.:
3.70%, 11/15/23			775		810,706
4.38%, 11/15/57			1,800		1,853,529
Hon Hai Precision Industry Co. Ltd., 0.00%, 11/06/22(g)(h)			600		576,095
LG Display Co. Ltd., 1.50%, 08/22/24(g)			600		607,398
					5,720,198
Energy Equipment & Services — 0.2%
Anton Oilfield Services Group/Hong Kong, 9.75%, 12/05/20			410		421,147
Bristow Group, Inc., 8.75%, 03/01/23(b)(f)(i)			4,619		4,526,620
Halliburton Co.:
3.80%, 11/15/25			11,850		12,551,795
7.45%, 09/15/39			95		135,310
4.75%, 08/01/43			183		197,436
Hilong Holding Ltd., 8.25%, 09/26/22			250		252,500
Nabors Industries, Inc., 5.50%, 01/15/23			2		1,645
Odebrecht Drilling Norbe VIII/IX Ltd., 6.35%, 12/01/21(b)			885		874,134
SEACOR Holdings, Inc., 3.25%, 05/15/30(g)			4,204		3,924,732
Transocean Guardian Ltd., 5.88%, 01/15/24(b)			1,058		1,060,856
Transocean Phoenix 2 Ltd., 7.75%, 10/15/24(b).			8,718		9,110,310
Transocean Proteus Ltd., 6.25%, 12/01/24(b)			875		888,379

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 47

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Energy Equipment & Services (continued)
Transocean, Inc., 9.00%, 07/15/23(b)	USD		1,797	$	1,846,418
					35,791,282
Equity Real Estate Investment Trusts (REITs) — 0.5%
American Tower Corp.:
3.30%, 02/15/21			60		60,857
2.25%, 01/15/22			120		120,158
4.70%, 03/15/22			20		21,188
3.50%, 01/31/23			4,832		5,006,064
3.00%, 06/15/23			1,030		1,053,618
5.00%, 02/15/24			1,063		1,174,497
3.38%, 05/15/24			170		176,695
2.95%, 01/15/25			1,660		1,695,031
4.00%, 06/01/25			2,279		2,435,862
4.40%, 02/15/26			118		129,324
3.38%, 10/15/26			2,523		2,623,896
2.75%, 01/15/27			1,475		1,472,610
3.13%, 01/15/27			541		551,885
3.95%, 03/15/29			1,740		1,873,983
3.80%, 08/15/29			3,514		3,750,511
Crown Castle International Corp.:
3.40%, 02/15/21			32		32,439
2.25%, 09/01/21			80		80,066
4.88%, 04/15/22			144		153,081
5.25%, 01/15/23			1,333		1,451,329
3.15%, 07/15/23			2,323		2,380,150
3.20%, 09/01/24			18,123		18,615,741
4.45%, 02/15/26			534		584,768
3.70%, 06/15/26			6,074		6,403,888
4.00%, 03/01/27			548		589,533
3.65%, 09/01/27			945		1,000,569
3.80%, 02/15/28			118		125,495
4.30%, 02/15/29			232		256,139
3.10%, 11/15/29			7,185		7,207,683
Equinix, Inc., 5.38%, 01/01/22			620		633,950
ESH Hospitality, Inc., 5.25%, 05/01/25(b)			300		310,200
GLP Capital LP/GLP Financing II, Inc.:
4.38%, 04/15/21			650		664,287
3.35%, 09/01/24			2,340		2,353,338
MGM Growth Properties Operating Partnership LP/MGP Finance Co-Issuer, Inc., 5.63%, 05/01/24			1,030		1,129,138
Prologis Euro Finance LLC, 1.50%, 09/10/49	EUR		1,010		1,051,764
Realty Income Corp.:
4.13%, 10/15/26	USD		2,860		3,150,141
3.00%, 01/15/27			865		891,289
Trust F/1401, 4.87%, 01/15/30(b)			1,856		1,909,070
					73,120,237
Food & Staples Retailing — 0.6%
Alimentation Couche-Tard, Inc., 3.55%, 07/26/27(b)			10,695		11,117,998
CVS Health Corp.:
4.10%, 03/25/25			7,921		8,463,310
2.88%, 06/01/26			714		715,642
4.88%, 07/20/35			910		1,013,717
4.78%, 03/25/38			971		1,063,423
5.13%, 07/20/45			15,122		17,140,198
5.05%, 03/25/48			2,100		2,383,350
Kroger Co., 2.65%, 10/15/26			4,198		4,159,360
Walgreens Boots Alliance, Inc.:
3.45%, 06/01/26			20,919		21,602,829
4.80%, 11/18/44			267		281,970
Walmart, Inc.:
3.55%, 06/26/25			4,279		4,619,480
3.25%, 07/08/29			8,153		8,807,561
3.95%, 06/28/38			6,100		7,145,850
4.00%, 04/11/43			2,215		2,597,458
4.30%, 04/22/44			255		315,618
					91,427,764

Security		Par (000)		Value
Food Products — 0.1%
BRF GmbH, 4.35%, 09/29/26(b)	USD		2,256	$	2,234,145
Campbell Soup Co., 8.88%, 05/01/21			2,350		2,567,567
Ezaki Glico Co. Ltd., 0.00%, 01/30/24(g)(h)	JPY		10,000		91,783
Grupo Bimbo SAB de CV, 4.00%, 09/06/49(b)	USD		2,420		2,279,943
JBS Investments II GmbH, 5.75%, 01/15/28(b)			2,377		2,475,646
Knight Castle Investments Ltd., 7.99%, 01/23/21			700		390,250
Marfrig Holdings Europe BV, 8.00%, 06/08/23(b)			1,600		1,666,500
MHP Lux SA, 6.25%, 09/19/29(b)			4,129		3,974,163
Tyson Foods, Inc.:
4.00%, 03/01/26			123		133,367
3.55%, 06/02/27			5,114		5,418,902
5.15%, 08/15/44			480		572,526
4.55%, 06/02/47			385		431,763
5.10%, 09/28/48			662		804,269
					23,040,824
Gas Utilities — 0.0%
Atmos Energy Corp.:
4.13%, 10/15/44			44		50,912
3.38%, 09/15/49			2,565		2,603,514
Piedmont Natural Gas Co., Inc., 3.64%, 11/01/46			427		440,050
					3,094,476
Health Care Equipment & Supplies — 0.3%
Abbott Laboratories:
3.40%, 11/30/23			1,079		1,131,611
3.75%, 11/30/26			18,829		20,513,130
Baxter International, Inc., 1.70%, 08/15/21			500		495,923
Becton Dickinson and Co.:
2.68%, 12/15/19			1,865		1,865,452
3.30%, 03/01/23			5,026		5,120,690
4.69%, 12/15/44			139		161,372
Covidien International Finance SA, 2.95%, 06/15/23			3,090		3,190,580
Edwards Lifesciences Corp., 4.30%, 06/15/28			856		964,239
Medtronic Global Holdings SCA:
0.00%, 12/02/22	EUR		1,995		2,177,763
0.38%, 03/07/23			1,720		1,896,704
1.63%, 03/07/31			535		647,288
Medtronic, Inc.:
3.50%, 03/15/25	USD		1,202		1,290,218
4.38%, 03/15/35			9,883		11,893,602
					51,348,572
Health Care Providers & Services — 1.4%
Aetna, Inc.:
4.50%, 05/15/42			5,358		5,654,289
4.13%, 11/15/42			1,329		1,330,609
4.75%, 03/15/44			1,703		1,866,300
AMN Healthcare, Inc., 5.13%, 10/01/24(b)			136		141,100
Anthem, Inc.:
3.50%, 08/15/24			473		495,731
3.65%, 12/01/27			238		250,088
4.10%, 03/01/28			1,795		1,938,714
2.88%, 09/15/29			1,625		1,607,967
Baylor Scott & White Holdings, 4.19%, 11/15/45			1,525		1,796,990
Catholic Health Initiatives, 4.35%, 11/01/42			1,075		1,152,256
CHRISTUS Health, 4.34%, 07/01/28			11,064		12,519,532
Cigna Corp.:
3.20%, 09/17/20			5,035		5,083,798
4.38%, 10/15/28			9,033		9,870,143
Cigna Holding Co., 3.25%, 04/15/25			6,379		6,567,854
CommonSpirit Health:
3.35%, 10/01/29			3,888		3,931,009
3.82%, 10/01/49			8,300		8,373,476
4.19%, 10/01/49			2,568		2,643,226

48 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Health Care Providers & Services (continued)
DH Europe Finance II Sarl:
0.20%, 03/18/26	EUR		3,010	$	3,270,722
0.45%, 03/18/28			2,080		2,270,360
1.35%, 09/18/39			660		719,700
Dignity Health:
2.64%, 11/01/19	USD		2,493		2,493,055
3.81%, 11/01/24			2,030		2,146,932
HCA, Inc.:
4.75%, 05/01/23			6,789		7,271,954
5.00%, 03/15/24			4,880		5,328,708
5.25%, 04/15/25			17,214		19,146,029
5.25%, 06/15/26			2,130		2,371,791
4.50%, 02/15/27			923		989,624
4.13%, 06/15/29			10,666		11,185,279
Laboratory Corp. of America Holdings, 2.63%, 02/01/20			2,946		2,948,065
Montefiore Obligated Group, 5.25%, 11/01/48			3,453		4,043,594
Ochsner Clinic Foundation, 5.90%, 05/15/45			783		1,084,788
PeaceHealth Obligated Group, 4.79%, 11/15/48			462		592,627
Redco Group, 13.50%, 01/21/20			490		492,450
SSM Health Care Corp., 3.69%, 06/01/23			8,263		8,679,539
Sutter Health, 3.70%, 08/15/28			3,083		3,350,412
Tenet Healthcare Corp.:
4.63%, 09/01/24(b)			7,363		7,574,171
4.88%, 01/01/26(b)			8,347		8,566,109
Toledo Hospital, 5.75%, 11/15/38			5,230		6,166,345
UnitedHealth Group, Inc.:
3.50%, 02/15/24			291		306,457
3.75%, 07/15/25			16,698		17,954,134
3.70%, 12/15/25			4,035		4,344,176
3.10%, 03/15/26			3,481		3,638,558
3.85%, 06/15/28			4,268		4,672,391
2.88%, 08/15/29			524		534,809
3.50%, 08/15/39			5,106		5,315,293
4.63%, 11/15/41			3,478		4,114,336
4.75%, 07/15/45			630		765,680
3.75%, 10/15/47			3,272		3,461,970
4.25%, 06/15/48			240		275,546
4.45%, 12/15/48			1,819		2,151,056
WuXi AppTec Co. Ltd., 0.00%, 09/17/24(g)(h)			500		524,448
					213,974,190
Hotels, Restaurants & Leisure — 0.3%
Carlson Travel, Inc., 9.50%, 12/15/24(b)			215		216,612
Carnival Corp., 1.88%, 11/07/22	EUR		160		184,310
Eldorado Resorts, Inc., 7.00%, 08/01/23	USD		296		309,320
HIS Co. Ltd., 0.00%, 11/15/24(g)(h)	JPY		40,000		366,295
International Game Technology PLC, 6.25%, 02/15/22(b)	USD		4,246		4,480,666
McDonald’s Corp.:
3.70%, 01/30/26			5,015		5,382,996
4.70%, 12/09/35			8		9,505
6.30%, 03/01/38			199		271,996
3.70%, 02/15/42			1,085		1,115,037
3.63%, 05/01/43			2,105		2,141,018
4.88%, 12/09/45			560		677,130
4.45%, 03/01/47			970		1,113,783
4.45%, 09/01/48			1,560		1,803,300
3.63%, 09/01/49			12,840		12,978,754
MGM Resorts International, 5.25%, 03/31/20			156		157,755
REXLot Holdings Ltd., 4.50%, 04/17/19(f)(g)(i)	HKD		1,161		44,433
Scientific Games International, Inc., 10.00%, 12/01/22	USD		3,985		4,144,400
Studio City Finance Ltd., 7.25%, 02/11/24			1,000		1,050,000
Vinpearl JSC, 3.50%, 06/14/23(g)			800		878,744
Wynn Resorts Finance LLC/Wynn Resorts Capital Corp., 5.13%, 10/01/29(b)			2,893		3,031,575
					40,357,629

Security		Par (000)		Value
Household Durables — 0.3%
Ashton Woods USA LLC/Ashton Woods Finance Co.:
6.75%, 08/01/25(b)	USD		1,069	$	1,066,327
9.88%, 04/01/27(b)			3,448		3,766,940
Beazer Homes USA, Inc., 7.25%, 10/15/29(b)			4,961		5,041,616
Brookfield Residential Properties, Inc., 6.50%, 12/15/20(b)			1,023		1,023,307
Brookfield Residential Properties, Inc./Brookfield Residential U.S. Corp.:
6.13%, 07/01/22(b)			467		474,287
6.25%, 09/15/27(b)			3,187		3,202,935
Century Communities, Inc., 6.75%, 06/01/27(b)			5,674		6,093,876
Harvest International Co., 0.00%, 11/21/22(g)(h)	HKD		8,000		1,023,897
Iida Group Holdings Co. Ltd., 0.00%, 06/18/20(g)(h)	JPY		100,000		911,789
KB Home:
8.00%, 03/15/20	USD		165		168,993
7.63%, 05/15/23			1,769		2,003,393
Lennar Corp.:
4.50%, 11/15/19			1,105		1,105,000
2.95%, 11/29/20			20		20,025
8.38%, 01/15/21			755		808,794
4.75%, 04/01/21			447		456,499
5.88%, 11/15/24			4,092		4,531,890
5.25%, 06/01/26			60		64,875
LGI Homes, Inc., 6.88%, 07/15/26(b)			1,069		1,111,760
PulteGroup, Inc.:
4.25%, 03/01/21			152		155,040
5.00%, 01/15/27			204		220,320
6.00%, 02/15/35			53		56,445
Shea Homes LP/Shea Homes Funding Corp., 5.88%, 04/01/23(b)			58		59,305
Toll Brothers Finance Corp.:
4.38%, 04/15/23			5,264		5,514,040
3.80%, 11/01/29			6,706		6,601,252
TRI Pointe Group, Inc., 5.25%, 06/01/27			2,378		2,383,945
Weekley Homes LLC/Weekley Finance Corp., 6.00%, 02/01/23			2,406		2,399,023
William Lyon Homes, Inc., 6.00%, 09/01/23			3,857		4,011,280
					54,276,853
Household Products — 0.0%
Clorox Co., 3.10%, 10/01/27			990		1,032,630
Procter & Gamble Co., 0.63%, 10/30/24	EUR		4,460		5,014,964
					6,047,594
Independent Power and Renewable Electricity Producers — 0.2%
AES Panama SRL, 6.00%, 06/25/22(b)	USD		527		540,669
Inkia Energy Ltd., 5.88%, 11/09/27(b)			1,009		1,045,261
NRG Energy, Inc.:
3.75%, 06/15/24(b)			554		570,072
7.25%, 05/15/26			1,725		1,889,306
4.45%, 06/15/29(b)			1,534		1,598,224
2.75%, 06/01/48(g)			2,906		3,265,927
Orazul Energy Egenor S en C por A, 5.63%, 04/28/27(b)			1,497		1,547,056
ReNew Power Ltd., 6.45%, 09/27/22			1,000		1,011,875
ReNew Power Synthetic, 6.67%, 03/12/24			800		810,250
Rio Energy SA/UGEN SA/UENSA SA, 6.88%, 02/01/25			1,381		662,880
Stoneway Capital Corp., 10.00%, 03/01/27(b)			6,024		3,452,353
Talen Energy Supply LLC:
6.50%, 06/01/25			3,071		2,333,960
10.50%, 01/15/26(b)			1,956		1,687,050
7.25%, 05/15/27(b)			3,890		3,953,407
Vistra Energy Corp., 5.88%, 06/01/23			350		357,525
					24,725,815

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 49

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Industrial Conglomerates — 0.3%
3M Co.:
3.00%, 08/07/25	USD		1,150	$	1,206,408
2.25%, 09/19/26			1,300		1,300,048
2.88%, 10/15/27			1,433		1,489,011
3.38%, 03/01/29			880		946,609
2.38%, 08/26/29			4,610		4,585,390
3.63%, 10/15/47			80		83,985
General Electric Co.:
5.88%, 01/14/38			1,199		1,441,657
6.88%, 01/10/39			297		392,913
4.13%, 10/09/42			567		567,355
Grupo KUO SAB de CV, 5.75%, 07/07/27(b)			3,203		3,220,016
Honeywell International, Inc.:
1.30%, 02/22/23	EUR		22,085		25,185,137
3.81%, 11/21/47	USD		1,640		1,887,818
Tyco Electronics Group SA:
3.45%, 08/01/24			865		903,277
3.13%, 08/15/27			1,837		1,888,559
					45,098,183
Insurance — 0.7%
Allianz Finance II BV:
0.25%, 06/06/23	EUR		3,500		3,865,195
1.38%, 04/21/31			2,300		2,811,772
Ambac Assurance Corp., 5.10%, 06/07/20(b)	USD		462		671,349
Ambac LSNI LLC, (3 mo. LIBOR US + 5.000%), 7.10%, 02/12/23(a)(b)			2,912		2,941,247
Aon Corp.:
4.50%, 12/15/28			8,860		9,999,906
3.75%, 05/02/29			8,811		9,400,474
Aon PLC, 4.75%, 05/15/45			1,475		1,732,416
Berkshire Hathaway Finance Corp.:
4.40%, 05/15/42			950		1,133,163
4.25%, 01/15/49			1,060		1,254,917
Brighthouse Financial, Inc., 4.70%, 06/22/47			365		325,621
China Reinsurance Finance Corp. Ltd., 3.38%, 03/09/22			1,311		1,314,278
Marsh & McLennan Cos., Inc.:
4.05%, 10/15/23			2,451		2,608,861
3.50%, 06/03/24			8,930		9,417,969
3.50%, 03/10/25			3,180		3,361,778
3.75%, 03/14/26			177		190,431
1.35%, 09/21/26	EUR		3,970		4,585,922
4.38%, 03/15/29	USD		5,140		5,813,321
4.35%, 01/30/47			657		756,713
4.20%, 03/01/48			4,532		5,109,615
4.90%, 03/15/49			23		28,812
MetLife, Inc., 4.13%, 08/13/42			494		550,300
Metropolitan Life Global Funding I:
0.00%, 09/23/22	EUR		2,810		3,071,077
2.38%, 01/11/23			2,607		3,063,511
Principal Financial Group, Inc., 3.70%, 05/15/29	USD		2,435		2,622,497
QBE Insurance Group Ltd., (10 yr. Swap Semi 30/360 US + 4.395%), 5.88%, 06/17/46(j)			450		483,658
T&D Holdings, Inc., 0.00%, 06/05/20(g)(h)	JPY		80,000		733,890
Travelers Cos., Inc.:
6.25%, 06/15/37	USD		65		92,038
4.60%, 08/01/43			3,224		3,964,221
4.00%, 05/30/47			32		36,669
4.10%, 03/04/49			289		337,702
Trinity Acquisition PLC, 4.40%, 03/15/26			1,850		2,006,222
Union Life Insurance Co. Ltd., 3.00%, 09/19/21	.		229		200,948
Willis North America, Inc.:
3.60%, 05/15/24			14,990		15,576,933
3.88%, 09/15/49			240		234,724
Zurich Finance Ireland Designated Activity Co.,
1.63%, 06/17/39	EUR		3,063		3,740,167
					104,038,317

Security		Par (000)		Value
Interactive Media & Services — 0.0%
Baidu, Inc., 4.38%, 05/14/24	USD		3,320	$	3,540,881
Tencent Holdings Ltd., 3.98%, 04/11/29			1,400		1,494,369
YY, Inc., 0.75%, 06/15/25(b)(g)			166		151,231
					5,186,481
Internet & Direct Marketing Retail — 0.1%
Alibaba Group Holding Ltd., 3.60%, 11/28/24			5,095		5,340,069
Amazon.com, Inc., 3.88%, 08/22/37			7,590		8,732,500
Baozun, Inc., 1.63%, 05/01/24(b)(g)			258		277,995
Expedia Group, Inc.:
3.80%, 02/15/28			760		795,396
3.25%, 02/15/30(b)			8,045		8,022,058
					23,168,018
IT Services — 1.1%
21Vianet Group, Inc., 7.88%, 10/15/21			485		489,777
Fidelity National Information Services, Inc.:
3.63%, 10/15/20			277		280,693
1.10%, 07/15/24	EUR		11,365		12,910,319
3.00%, 08/15/26	USD		15,395		15,851,451
2.95%, 05/21/39	EUR		886		1,187,897
4.50%, 08/15/46	USD		1,179		1,366,769
4.75%, 05/15/48			3,790		4,597,259
Fiserv, Inc.:
4.75%, 06/15/21			1,600		1,665,988
3.85%, 06/01/25			1,580		1,689,030
3.20%, 07/01/26			18,059		18,689,173
4.20%, 10/01/28			9,909		10,961,342
3.50%, 07/01/29			3,204		3,370,984
1.63%, 07/01/30	EUR		6,360		7,453,230
Global Payments, Inc.:
2.65%, 02/15/25	USD		2,175		2,185,069
3.20%, 08/15/29			8,850		8,974,706
International Business Machines Corp.:
2.90%, 11/01/21			535		545,276
3.63%, 02/12/24			5,876		6,231,517
3.30%, 05/15/26			22,011		23,211,066
5.60%, 11/30/39			1		1,319
4.70%, 02/19/46			378		459,015
LINE Corp., 0.00%, 09/19/25(g)(h)	JPY		70,000		607,220
Mastercard, Inc.:
2.95%, 11/21/26	USD		2,250		2,367,201
2.95%, 06/01/29			8,265		8,669,334
3.65%, 06/01/49			1,535		1,738,747
PayPal Holdings, Inc.:
2.40%, 10/01/24			1,510		1,518,186
2.65%, 10/01/26			1,780		1,792,261
Sabre GLBL, Inc., 5.25%, 11/15/23(b)			300		308,250
Total System Services, Inc.:
3.80%, 04/01/21			1,910		1,950,134
3.75%, 06/01/23			2,350		2,445,681
4.00%, 06/01/23			236		247,730
4.80%, 04/01/26			9,197		10,218,314
Transcosmos, Inc., 0.00%, 12/22/20(g)(h)	JPY		40,000		365,840
VeriSign, Inc., 4.63%, 05/01/23	USD		9,359		9,513,424
Visa, Inc.:
4.15%, 12/14/35			3,879		4,672,885
4.30%, 12/14/45			2,265		2,810,740
					171,347,827
Life Sciences Tools & Services — 0.2%
Agilent Technologies, Inc.:
3.88%, 07/15/23			658		691,517
3.05%, 09/22/26			9,644		9,848,939
2.75%, 09/15/29			1,415		1,399,408
Thermo Fisher Scientific, Inc.:
2.95%, 09/19/26			17,354		17,879,254
2.60%, 10/01/29			7,760		7,729,873
5.30%, 02/01/44			300		382,573
					37,931,564

50 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Machinery — 0.0%
Atlas Copco AB, 2.50%, 02/28/23	EUR		3,455	$	4,110,300
Atlas Copco Finance DAC, 0.13%, 09/03/29			1,110		1,183,026
China Conch Venture Holdings International Ltd., 0.00%, 09/05/23(g)(h)	HKD		6,000		790,303
CNH Industrial NV, 3.85%, 11/15/27	USD		870		896,546
Gates Global LLC/Gates Global Co., 6.00%, 07/15/22(b)			445		443,331
					7,423,506
Marine — 0.0%
MV24 Capital BV, 6.75%, 06/01/34(b)			1,653		1,702,828
Media — 1.2%
CCO Holdings LLC/CCO Holdings Capital Corp.:
5.13%, 02/15/23			307		311,989
5.13%, 05/01/23(b)			305		312,546
5.75%, 01/15/24			153		156,442
Charter Communications Operating LLC/Charter Communications Operating Capital:
(3 mo. LIBOR US + 1.650%), 3.90%, 02/01/24(a)			208		213,172
4.50%, 02/01/24			5,989		6,434,122
4.91%, 07/23/25			5,801		6,363,437
4.20%, 03/15/28			3,039		3,196,001
5.05%, 03/30/29			955		1,068,427
6.38%, 10/23/35			10,062		12,183,425
6.48%, 10/23/45			17,314		21,068,137
5.38%, 05/01/47			653		711,487
Clear Channel Worldwide Holdings, Inc., 5.13%, 08/15/27(b)			333		346,936
Comcast Corp.:
3.30%, 10/01/20			13,872		14,060,867
3.38%, 02/15/25			1,054		1,111,385
3.15%, 03/01/26			9,094		9,522,187
2.35%, 01/15/27			740		736,863
3.15%, 02/15/28			1,993		2,077,237
4.15%, 10/15/28			756		848,025
4.25%, 10/15/30			2,493		2,835,770
4.25%, 01/15/33			717		824,604
4.20%, 08/15/34			2,107		2,408,001
4.40%, 08/15/35			2,300		2,679,065
6.50%, 11/15/35			1,550		2,171,684
3.20%, 07/15/36			19,163		19,605,229
6.95%, 08/15/37			61		89,521
4.60%, 10/15/38			1,062		1,268,666
4.75%, 03/01/44			68		82,560
3.40%, 07/15/46			6,948		7,105,162
3.97%, 11/01/47			929		1,020,241
4.70%, 10/15/48			2,532		3,100,290
4.00%, 11/01/49			1,611		1,789,196
Cox Communications, Inc.:
3.15%, 08/15/24(b)			14,176		14,517,670
3.35%, 09/15/26(b)			894		923,369
CSC Holdings LLC, 10.88%, 10/15/25(b)			777		879,914
Discovery Communications LLC:
5.00%, 09/20/37			3,814		4,100,057
4.95%, 05/15/42			275		288,894
5.20%, 09/20/47			2,498		2,731,441
Fox Corp., 4.03%, 01/25/24(b)			2,145		2,280,713
Historic TW, Inc., 6.63%, 05/15/29			420		531,247
Kakao Corp., 0.00%, 05/11/21(g)(h)	KRW		400,000		383,836
Lamar Media Corp., 5.38%, 01/15/24	USD		463		475,154
NBCUniversal Media LLC:
6.40%, 04/30/40			89		126,604
5.95%, 04/01/41			4,270		5,874,888
4.45%, 01/15/43			4,239		4,914,367
Sirius XM Radio, Inc., 4.63%, 07/15/24(b)			1,750		1,814,453
Time Warner Cable LLC:
5.00%, 02/01/20			2,900		2,923,443
4.00%, 09/01/21			911		932,060

Security		Par (000)		Value
Media (continued)
Time Warner Cable LLC: (continued)
5.50%, 09/01/41	USD		3,125	$	3,365,006
4.50%, 09/15/42			314		308,991
TWDC Enterprises 18 Corp., 7.00%, 03/01/32			210		308,172
Viacom, Inc.:
3.88%, 12/15/21			78		80,627
4.25%, 09/01/23			30		31,813
6.88%, 04/30/36			2,944		3,848,416
5.85%, 09/01/43			210		257,573
Walt Disney Co.:
6.20%, 12/15/34(b)			1,217		1,731,276
6.40%, 12/15/35(b)			3,227		4,649,136
6.65%, 11/15/37(b)			1,190		1,788,408
4.75%, 09/15/44(b)			960		1,243,672
Warner Media LLC, 7.63%, 04/15/31			1,815		2,463,445
					189,477,319
Metals & Mining — 0.3%
Anglo American Capital PLC:
3.63%, 09/11/24(b)			7,445		7,691,228
4.75%, 04/10/27(b)			4,150		4,475,312
4.50%, 03/15/28(b)			984		1,044,640
ArcelorMittal:
3.60%, 07/16/24			94		94,957
6.13%, 06/01/25			2,700		3,038,251
4.55%, 03/11/26			319		333,771
Barrick Gold Corp., 5.25%, 04/01/42			2,009		2,437,379
Barrick PD Australia Finance Pty Ltd., 5.95%, 10/15/39			360		464,127
BHP Billiton Finance Ltd., 3.13%, 04/29/33	EUR		1,500		2,139,242
Evraz PLC, 5.25%, 04/02/24(b)	USD		1,103		1,166,423
Industrias Penoles SAB de CV, 4.15%, 09/12/29(b)			2,303		2,303,000
Kaiser Aluminum Corp., 5.88%, 05/15/24			82		85,371
Minera Mexico SA de CV, 4.50%, 01/26/50(b)			3,933		3,849,030
Newmont Goldcorp Corp.:
2.80%, 10/01/29			3,260		3,221,784
4.88%, 03/15/42			95		112,021
Novolipetsk Steel Via Steel Funding DAC, 4.70%, 05/30/26(b)			2,149		2,302,788
Nucor Corp., 5.20%, 08/01/43			1,640		2,046,351
Shandong Iron And Steel Xinheng International Co. Ltd., 6.50%, 06/14/21			285		286,870
Steel Dynamics, Inc.:
5.13%, 10/01/21			2,954		2,964,516
5.25%, 04/15/23			312		317,460
Teck Resources Ltd., 6.25%, 07/15/41			684		760,219
Usiminas International Sarl, 5.88%, 07/18/26(b)			2,094		2,115,621
Vale Overseas Ltd., 4.38%, 01/11/22			1,494		1,545,823
Vedanta Resources Finance II PLC, 8.00%, 04/23/23			500		502,500
Vedanta Resources PLC, 6.38%, 07/30/22			586		575,196
Zekelman Industries, Inc., 9.88%, 06/15/23(b)			151		159,116
					46,032,996
Multiline Retail — 0.0%
Dollar General Corp., 3.88%, 04/15/27			998		1,069,646
Multi-Utilities — 0.4%
Alliant Energy Finance LLC, 3.75%, 06/15/23(b)			1,748		1,827,210
Ameren Illinois Co., 3.80%, 05/15/28			3,671		4,080,442
Berkshire Hathaway Energy Co., 5.15%, 11/15/43			380		480,575
Black Hills Corp., 3.95%, 01/15/26			1,812		1,915,215
Consumers Energy Co.:
3.95%, 05/15/43			5		5,692
3.25%, 08/15/46			995		1,017,952
3.95%, 07/15/47			410		467,575
4.05%, 05/15/48			1,325		1,536,428
3.75%, 02/15/50			3,627		4,047,914

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 51

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Multi-Utilities (continued)
Consumers Energy Co.: (continued)
3.10%, 08/15/50	USD		2,045	$	2,059,514
Dominion Energy Gas Holdings LLC:
4.80%, 11/01/43			1,110		1,324,757
4.60%, 12/15/44			3,485		4,116,261
DTE Energy Co., 3.70%, 08/01/23			2,960		3,103,751
Engie SA:
0.00%, 03/04/27	EUR		2,700		2,906,878
1.38%, 06/21/39			1,500		1,781,532
NiSource, Inc., 3.49%, 05/15/27	USD		2,860		2,999,331
Veolia Environnement SA, 0.67%, 03/30/22	EUR		1,600		1,772,436
Virginia Electric & Power Co.:
Series C, 2.75%, 03/15/23	USD		6,506		6,641,555
Series A, 3.50%, 03/15/27			6,512		6,946,793
4.00%, 01/15/43			5,490		6,086,915
Series C, 4.00%, 11/15/46			6,944		7,758,139
Wisconsin Power & Light Co., 3.00%, 07/01/29	.		878		915,570
					63,792,435
Oil, Gas & Consumable Fuels — 3.7%
Andeavor Logistics LP/Tesoro Logistics Finance Corp.:
5.50%, 10/15/19			16,323		16,340,174
4.25%, 12/01/27			60		63,360
5.20%, 12/01/47			180		194,398
Antero Resources Corp., 5.38%, 11/01/21			6,681		6,447,165
Boardwalk Pipelines LP, 4.80%, 05/03/29			640		679,696
BP Capital Markets America, Inc.:
3.79%, 02/06/24			3,688		3,919,489
3.80%, 09/21/25			7,819		8,435,454
3.12%, 05/04/26			2,440		2,543,948
3.94%, 09/21/28			574		636,091
BP Capital Markets PLC:
2.32%, 02/13/20			1,834		1,835,952
1.53%, 09/26/22	EUR		1,455		1,661,292
1.11%, 02/16/23			1,565		1,770,249
3.28%, 09/19/27	USD		156		164,191
Bruin E&P Partners LLC, 8.88%, 08/01/23(b)			3,001		2,243,247
Carrizo Oil & Gas, Inc., 6.25%, 04/15/23			844		799,690
Centennial Resource Production LLC:
5.38%, 01/15/26(b)			297		282,150
6.88%, 04/01/27(b)			1,460		1,456,350
Cheniere Corpus Christi Holdings LLC:
7.00%, 06/30/24			5,227		6,007,391
5.88%, 03/31/25			205		228,089
Cheniere Energy Partners LP, 5.25%, 10/01/25	.		156		161,850
Cheniere Energy, Inc., 4.88% (4.88 Cash or 4.88% PIK), 05/28/21(b)(g)(l)			15,300		15,607,224
Chesapeake Energy Corp.:
6.63%, 08/15/20			623		626,115
6.13%, 02/15/21			260		255,450
5.50%, 09/15/26(g)			3,640		2,174,900
Chevron Corp.:
2.36%, 12/05/22			130		131,768
3.19%, 06/24/23			170		177,236
2.90%, 03/03/24			2,210		2,293,039
Cimarex Energy Co.:
4.38%, 06/01/24			2,560		2,689,963
3.90%, 05/15/27			3,824		3,893,461
Concho Resources, Inc., 3.75%, 10/01/27			4,145		4,308,154
Continental Resources, Inc.:
5.00%, 09/15/22			5,064		5,108,425
3.80%, 06/01/24			4,876		4,968,910
CVR Refining LLC/Coffeyville Finance, Inc., 6.50%, 11/01/22			311		314,887
Devon Energy Corp., 5.85%, 12/15/25			5,062		6,016,687
Diamondback Energy, Inc.:
4.75%, 11/01/24			4,995		5,113,631
5.38%, 05/31/25			7,684		8,018,715

Security		Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
Enbridge, Inc.:
2.90%, 07/15/22	USD		2,385	$	2,430,037
3.70%, 07/15/27			4,318		4,581,996
Endeavor Energy Resources LP/EER Finance, Inc., 5.50%, 01/30/26(b)			2,532		2,633,280
Energen Corp., 4.63%, 09/01/21			377		387,839
Energy Transfer Operating LP:
7.50%, 10/15/20			5,092		5,351,163
5.88%, 01/15/24			4,069		4,523,339
4.90%, 02/01/24			159		171,245
4.50%, 04/15/24			14		14,923
4.20%, 04/15/27			507		534,130
5.50%, 06/01/27			3,976		4,498,029
5.80%, 06/15/38			226		258,635
6.50%, 02/01/42			9,966		11,954,030
5.95%, 10/01/43			439		496,848
5.15%, 03/15/45			281		294,937
6.13%, 12/15/45			2,635		3,091,357
5.30%, 04/15/47			384		413,051
Ensco Jersey Finance Ltd., 3.00%, 01/31/24(g)			1,020		688,500
Enterprise Products Operating LLC:
3.90%, 02/15/24			536		570,567
3.75%, 02/15/25			753		802,291
6.88%, 03/01/33			2,153		2,955,686
6.65%, 10/15/34			205		282,714
6.13%, 10/15/39			131		170,118
4.45%, 02/15/43			5,728		6,262,550
4.85%, 03/15/44			576		661,292
5.10%, 02/15/45			3,142		3,699,154
4.90%, 05/15/46			214		251,496
4.25%, 02/15/48			329		355,555
4.80%, 02/01/49			476		554,241
EOG Resources, Inc.:
4.15%, 01/15/26			756		836,107
3.90%, 04/01/35			398		443,214
Exxon Mobil Corp.:
2.22%, 03/01/21			18		18,094
1.90%, 08/16/22			326		327,419
2.71%, 03/06/25			7,116		7,348,390
2.28%, 08/16/26			6,886		6,939,788
3.00%, 08/16/39			10		10,002
3.57%, 03/06/45			380		412,965
3.10%, 08/16/49			5,474		5,495,680
Frontera Energy Corp., 9.70%, 06/25/23(b)			1,316		1,391,259
Gran Tierra Energy, Inc., 7.75%, 05/23/27(b)			1,723		1,619,620
Great Western Petroleum LLC/Great Western Finance Corp., 9.00%, 09/30/21(b)			6,447		5,608,890
Hammerhead Resources, Inc., 9.00%, 07/10/22			4,789		4,262,210
Hess Corp., 6.00%, 01/15/40			1,521		1,761,972
Kinder Morgan Energy Partners LP:
4.25%, 09/01/24			1,607		1,723,109
5.80%, 03/15/35			1,923		2,258,340
6.50%, 02/01/37			4,900		6,086,043
6.95%, 01/15/38			401		523,472
6.38%, 03/01/41			462		566,349
5.63%, 09/01/41			85		96,799
5.00%, 03/01/43			3,564		3,910,929
Kinder Morgan, Inc.:
3.05%, 12/01/19			7,370		7,374,108
3.15%, 01/15/23			12,130		12,416,330
4.30%, 03/01/28			7,845		8,507,997
5.05%, 02/15/46			5,348		5,931,281
Marathon Petroleum Corp.:
4.75%, 12/15/23			2,680		2,907,060
5.13%, 12/15/26			225		252,902

52 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
Marathon Petroleum Corp.: (continued) 5.85%, 12/15/45	USD		1,915	$	2,178,576
Medco Straits Services Pte Ltd., 8.50%, 08/17/22			1,250		1,339,453
MPLX LP:
(3 mo. LIBOR US + 0.900%), 3.00%, 09/09/21(a)			8,515		8,543,270
(3 mo. LIBOR US + 1.100%), 3.20%, 09/09/22(a)			14,554		14,599,918
6.38%, 05/01/24(b)			207		217,124
4.88%, 12/01/24			9,330		10,241,826
5.25%, 01/15/25(b)			850		897,226
4.00%, 02/15/25			2,190		2,313,891
4.13%, 03/01/27			18,399		19,403,197
4.25%, 12/01/27(b)			21,078		22,300,318
NGPL PipeCo LLC, 4.38%, 08/15/22(b)			6,149		6,374,085
Northern Oil and Gas, Inc., 8.50% (8.50% Cash or 9.50% PIK), 05/15/23(l)			2,516		2,591,136
Northwest Pipeline LLC, 4.00%, 04/01/27			10,235		10,797,255
Oasis Petroleum, Inc., 6.50%, 11/01/21			1,547		1,522,836
Occidental Petroleum Corp.:
4.85%, 03/15/21			119		123,061
2.60%, 08/13/21			7,863		7,914,216
3.13%, 02/15/22			50		50,784
2.70%, 08/15/22			18,474		18,645,908
2.70%, 02/15/23			3,570		3,588,941
2.90%, 08/15/24			3,425		3,450,631
3.50%, 06/15/25			927		953,060
3.50%, 08/15/29			4,352		4,413,801
0.00%, 10/10/36(h)			24,055		11,880,283
4.40%, 04/15/46			2,433		2,478,145
4.20%, 03/15/48			650		644,077
Odebrecht Offshore Drilling Finance Ltd.:
6.72%, 12/01/22(b)			1,041		1,023,333
7.72% (7.72% Cash or 7.72% PIK), 12/01/26(b)(l)			39		9,956
Odebrecht Oil & Gas Finance Ltd., 0.00%(b)(h)(k)			193		963
Pacific Drilling SA, 8.38%, 10/01/23(b)			2,340		1,965,600
Parsley Energy LLC/Parsley Finance Corp.:
6.25%, 06/01/24(b)			2,004		2,074,140
5.25%, 08/15/25(b)			500		507,355
Plains All American Pipeline LP/PAA Finance Corp., 3.65%, 06/01/22			184		188,725
Puma International Financing SA, 5.00%, 01/24/26(b)			2,288		2,156,439
Rockies Express Pipeline LLC, 5.63%, 04/15/20(b)			10,242		10,382,828
Sabine Pass Liquefaction LLC:
5.63%, 02/01/21			165		170,431
6.25%, 03/15/22			4,179		4,502,740
5.63%, 04/15/23			7,074		7,686,410
5.75%, 05/15/24			12,723		14,181,206
5.63%, 03/01/25			14,635		16,432,732
5.88%, 06/30/26			6,070		6,954,999
Sable Permian Resources Land LLC/AEPB Finance Corp., 13.00%, 11/30/20(b)(f)(i)			1,080		1,112,400
Spectra Energy Partners LP:
3.38%, 10/15/26			80		82,797
4.50%, 03/15/45			6,555		7,129,290
Suncor Energy, Inc.:
3.60%, 12/01/24			2,534		2,672,745
6.80%, 05/15/38(m)			1,770		2,481,860
6.50%, 06/15/38(n)			200		275,406
4.00%, 11/15/47			883		948,653
Sunoco Logistics Partners Operations LP:
4.65%, 02/15/22			1,115		1,168,872
5.30%, 04/01/44			52		54,932

Security		Par (000)		Value
Oil, Gas & Consumable Fuels (continued)
Sunoco Logistics Partners Operations LP: (continued)
5.35%, 05/15/45	USD		2,360	$	2,532,171
5.40%, 10/01/47			1,748		1,907,255
Talos Production LLC/Talos Production Finance, Inc., 11.00%, 04/03/22			5,130		5,232,600
Targa Resources Partners LP/Targa Resources Partners Finance Corp., 5.13%, 02/01/25			154		158,366
Texas Eastern Transmission LP:
3.50%, 01/15/28(b)			4,350		4,523,322
4.15%, 01/15/48(b)			2,200		2,316,594
Total Capital Canada Ltd., 2.75%, 07/15/23			200		205,530
TransCanada PipeLines Ltd.:
4.88%, 01/15/26			11,120		12,482,806
4.25%, 05/15/28			3,315		3,664,548
4.63%, 03/01/34			357		405,603
5.85%, 03/15/36			1,026		1,264,919
4.75%, 05/15/38			1,307		1,491,051
6.10%, 06/01/40			3,796		4,899,352
5.10%, 03/15/49			27		32,417
Transcontinental Gas Pipe Line Co. LLC:
7.85%, 02/01/26			3,073		3,897,788
4.00%, 03/15/28			6,240		6,672,825
4.45%, 08/01/42			440		467,636
4.60%, 03/15/48			1,270		1,406,288
Valero Energy Corp.:
3.65%, 03/15/25			1,461		1,545,879
3.40%, 09/15/26			6,091		6,228,918
4.35%, 06/01/28			705		765,285
4.00%, 04/01/29			53		56,366
Western Midstream Operating LP:
4.00%, 07/01/22			940		951,358
4.65%, 07/01/26			2,305		2,277,480
5.45%, 04/01/44			720		638,415
Whiting Petroleum Corp., 1.25%, 04/01/20(g)			451		439,842
Williams Cos., Inc.:
4.55%, 06/24/24			1,879		2,022,379
3.75%, 06/15/27			3,149		3,252,561
7.50%, 01/15/31			2,180		2,864,197
5.75%, 06/24/44			2,630		3,035,015
Yankuang Group Cayman Ltd., 4.75%, 11/30/20			770		773,835
					585,528,554
Paper & Forest Products — 0.2%
Celulosa Arauco y Constitucion SA, 4.25%, 04/30/29(b)			1,305		1,357,990
Daio Paper Corp., 0.00%, 09/17/20(g)(h)	JPY		140,000		1,306,520
Eldorado Intl. Finance GmbH, 8.63%, 06/16/21(b)	USD		1,939		2,022,619
Georgia-Pacific LLC:
5.40%, 11/01/20(b)			3,718		3,845,963
3.73%, 07/15/23(b)			3,907		4,103,844
3.60%, 03/01/25(b)			1,475		1,564,626
7.38%, 12/01/25			3,288		4,166,414
7.75%, 11/15/29			1,275		1,820,000
8.88%, 05/15/31			528		836,505
Suzano Austria GmbH:
6.00%, 01/15/29			1,548		1,671,066
5.00%, 01/15/30			1,075		1,078,225
7.00%, 03/16/47(b)			2,148		2,447,915
					26,221,687
Personal Products — 0.0%
Top Glove Labuan Ltd., 2.00%, 03/01/24(g)			800		781,824
Pharmaceuticals — 0.9%
Allergan Finance LLC, 3.25%, 10/01/22			975		995,836

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 53

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Pharmaceuticals (continued)
Allergan Funding SCS:
3.80%, 03/15/25	USD		12,976	$	13,587,545
4.55%, 03/15/35			7,054		7,488,234
Bausch Health Cos., Inc., 6.50%, 03/15/22(b)			5,656		5,846,890
Bayer U.S. Finance II LLC:
3.88%, 12/15/23(b)			910		950,589
3.38%, 07/15/24(b)			393		401,972
2.85%, 04/15/25(b)			2,800		2,697,872
4.25%, 12/15/25(b)			200		213,671
3.60%, 07/15/42(b)			2,845		2,447,993
4.40%, 07/15/44(b)			115		116,038
Bayer U.S. Finance LLC, 3.38%, 10/08/24(b)			2,902		2,973,599
Bristol-Myers Squibb Co.:
3.20%, 06/15/26(b)			18,677		19,594,321
3.40%, 07/26/29(b)			2,300		2,456,680
4.13%, 06/15/39(b)			10		11,332
Eli Lilly & Co., 4.15%, 03/15/59			3,890		4,580,242
Johnson & Johnson, 2.45%, 03/01/26			1,273		1,295,319
Jubilant Pharma Ltd., 6.00%, 03/05/24			700		721,555
Luye Pharma Group Ltd., 1.50%, 07/09/24(g)			1,100		1,152,250
Merck & Co., Inc.:
3.90%, 03/07/39			49		56,793
3.60%, 09/15/42			835		920,199
3.70%, 02/10/45			1,765		1,990,531
Mylan, Inc.:
5.40%, 11/29/43			1,120		1,178,318
5.20%, 04/15/48			1,774		1,877,965
Novartis Capital Corp.:
3.40%, 05/06/24			4,367		4,641,323
3.00%, 11/20/25			2,405		2,531,413
3.10%, 05/17/27			2,405		2,555,702
4.40%, 05/06/44			945		1,168,954
Pfizer, Inc.:
4.00%, 12/15/36			2,145		2,455,660
4.30%, 06/15/43			66		77,345
4.40%, 05/15/44			283		337,008
4.13%, 12/15/46			137		158,971
Roche Finance Europe BV:
0.50%, 02/27/23	EUR		1,930		2,153,677
0.88%, 02/25/25			4,100		4,696,935
Shire Acquisitions Investments Ireland DAC:
2.88%, 09/23/23	USD		4,400		4,485,579
3.20%, 09/23/26			10,946		11,294,049
Takeda Pharmaceutical Co. Ltd., 5.00%, 11/26/28(b)			11,845		13,865,694
Teva Pharmaceutical Finance IV LLC, 2.25%, 03/18/20			4,322		4,264,599
Wyeth LLC:
6.45%, 02/01/24			985		1,160,991
5.95%, 04/01/37			5,789		7,863,422
					137,267,066
Professional Services — 0.0%
Nielsen Finance LLC/Nielsen Finance Co., 4.50%, 10/01/20			110		110,285
Real Estate Management & Development — 0.3%
Alam Synergy Pte Ltd., 6.63%, 04/24/22			415		392,519
Arrow Bidco LLC, 9.50%, 03/15/24(b)			2,177		2,177,000
Central China Real Estate Ltd.:
7.33%, 01/27/20			455		452,725
6.88%, 10/23/20			500		498,750
6.50%, 03/05/21			260		257,299
6.75%, 11/08/21			435		426,726
CFLD Cayman Investment Ltd.:
8.63%, 02/28/21			581		592,620
8.60%, 04/08/24			519		513,648
China Aoyuan Group Ltd.:
7.95%, 09/07/21			265		273,281

Security		Par (000)		Value
Real Estate Management & Development (continued)
China Aoyuan Group Ltd.: (continued)
8.50%, 01/23/22	USD		640	$	667,200
7.95%, 02/19/23			1,765		1,804,712
China Evergrande Group:
6.25%, 06/28/21			213		191,966
9.50%, 04/11/22			465		424,894
4.25%, 02/14/23(g)	HKD		15,000		1,678,187
10.00%, 04/11/23	USD		600		541,446
7.50%, 06/28/23			800		661,750
8.75%, 06/28/25			900		725,906
China SCE Group Holdings Ltd.:
7.45%, 04/17/21			400		405,524
7.25%, 04/19/23			800		777,000
7.38%, 04/09/24			800		765,000
CIFI Holdings Group Co. Ltd.:
6.88%, 04/23/21			980		999,698
5.50%, 01/23/22			1,300		1,283,750
Country Garden Holdings Co. Ltd.:
8.00%, 01/27/24			200		216,750
6.15%, 09/17/25			560		571,200
Esic Sukuk Ltd., 3.94%, 07/30/24			1,500		1,490,625
Fantasia Holdings Group Co. Ltd.:
8.38%, 03/08/21			510		475,734
11.75%, 04/17/22			230		216,850
7.95%, 07/05/22			530		452,984
Five Point Operating Co. LP/Five Point Capital Corp., 7.88%, 11/15/25(b)			4,247		4,310,705
Forestar Group, Inc., 8.00%, 04/15/24(b)			9,456		10,212,480
Future Land Development Holdings Ltd.:
6.50%, 09/12/20			300		290,438
7.50%, 01/22/21			700		670,688
Global Prime Capital Pte Ltd., 7.25%, 04/26/21			440		453,706
Jingrui Holdings Ltd., 9.45%, 04/23/21			700		642,383
Kaisa Group Holdings Ltd., 8.50%, 06/30/22			254		230,743
KWG Group Holdings Ltd., 5.88%, 11/10/24			200		179,063
Logan Property Holdings Co. Ltd.:
6.88%, 04/24/21			285		290,677
6.50%, 07/16/23			700		694,094
Longfor Group Holdings Ltd., 3.95%, 09/16/29			620		608,762
New Metro Global Ltd., 6.50%, 04/23/21			600		563,646
No Va Land Investment Group Corp., 5.50%, 04/27/23(g)			1,500		1,474,687
NWD MTN Ltd., 4.13%, 07/18/29			1,200		1,189,125
Realogy Group LLC/Realogy Co-Issuer Corp., 9.38%, 04/01/27(b)			410		380,898
Ronshine China Holdings Ltd.:
11.25%, 08/22/21			265		279,459
8.75%, 10/25/22			530		528,675
8.95%, 01/22/23			705		700,594
Scenery Journey Ltd., 11.00%, 11/06/20			1,200		1,198,500
Shimao Property Holdings Ltd., 5.60%, 07/15/26			200		204,250
Shui On Development Holding Ltd., (5 yr. Swap Semi 30/360 US + 8.809%), 7.50%(g)(j)(k)			500		525,000
Singha Estate PCL, 2.00%, 07/20/22(g)			1,000		989,688
Sunac China Holdings Ltd., 7.25%, 06/14/22			605		589,119
Times China Holdings Ltd.:
7.63%, 02/21/22			800		819,000
5.75%, 04/26/22			500		490,765
Wanda Group Overseas Ltd., 7.50%, 07/24/22			640		626,400
Xinyuan Real Estate Co. Ltd., 9.88%, 03/19/20			410		386,425
Yanlord Land HK Co. Ltd., 6.80%, 02/27/24			680		700,196
Yuzhou Properties Co. Ltd.:
8.63%, 01/23/22			700		719,250
6.00%, 10/25/23			620		566,525

54 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Real Estate Management & Development (continued)
Yuzhou Properties Co. Ltd.: (continued) 8.50%, 02/26/24	USD		700	$	685,563
Zhenro Properties Group Ltd., 8.70%, 08/03/22			600		590,189
					52,727,437
Road & Rail — 0.6%
Burlington Northern Santa Fe LLC:
3.00%, 04/01/25			625		651,880
6.15%, 05/01/37			988		1,390,221
5.75%, 05/01/40			4,663		6,273,369
5.05%, 03/01/41			399		499,060
4.40%, 03/15/42			255		299,235
4.55%, 09/01/44			2,028		2,434,691
4.15%, 04/01/45			5,095		5,861,764
4.05%, 06/15/48			845		969,365
CSX Corp.:
3.80%, 03/01/28			105		114,405
4.25%, 03/15/29			1,995		2,252,632
6.15%, 05/01/37			875		1,150,593
5.50%, 04/15/41			285		359,731
3.80%, 11/01/46			599		629,257
4.30%, 03/01/48			3,703		4,169,306
4.75%, 11/15/48			2,300		2,773,159
4.50%, 03/15/49			50		58,790
3.35%, 09/15/49			3,201		3,127,173
3.95%, 05/01/50			350		374,022
4.25%, 11/01/66			2,578		2,734,553
Norfolk Southern Corp.:
3.65%, 08/01/25			4,095		4,376,882
2.90%, 06/15/26			5,595		5,771,327
4.84%, 10/01/41			485		582,254
4.45%, 06/15/45			35		40,281
3.94%, 11/01/47			225		244,293
4.10%, 05/15/49			462		516,606
4.05%, 08/15/52			4,322		4,722,851
Penske Truck Leasing Co. LP/PTL Finance Corp.:
4.45%, 01/29/26(b)			3,900		4,211,503
3.40%, 11/15/26(b)			1,079		1,102,784
4.20%, 04/01/27(b)			2,992		3,183,849
Ryder System, Inc.:
2.25%, 09/01/21			66		65,990
2.80%, 03/01/22			66		66,837
2.50%, 09/01/22			345		347,436
3.40%, 03/01/23			2,600		2,686,078
Union Pacific Corp.:
3.15%, 03/01/24			2,885		2,996,075
2.75%, 03/01/26			4,737		4,811,060
3.38%, 02/01/35			6,037		6,232,727
3.60%, 09/15/37			4,839		5,100,815
3.55%, 08/15/39			407		426,111
4.75%, 09/15/41			1,100		1,290,444
4.05%, 11/15/45			100		109,960
4.50%, 09/10/48			396		472,522
4.30%, 03/01/49			170		197,591
3.80%, 10/01/51			824		881,106
3.88%, 02/01/55			4,114		4,291,640
3.95%, 08/15/59			1,409		1,494,925
Union Pacific Railroad Co. Pass-Through Trust, Series 2014-1, 3.23%, 05/14/26			2,778		2,901,926
					95,249,079
Semiconductors & Semiconductor Equipment — 1.0%
Analog Devices, Inc.:
3.90%, 12/15/25			485		521,585
3.50%, 12/05/26			2,953		3,092,682
Applied Materials, Inc.:
3.30%, 04/01/27			8,055		8,571,095
5.10%, 10/01/35			3,720		4,714,811

Security		Par (000)		Value
Semiconductors & Semiconductor Equipment (continued)
Applied Materials, Inc.: (continued)
5.85%, 06/15/41	USD		645	$	880,309
4.35%, 04/01/47			5,713		6,971,372
Broadcom Corp./Broadcom Cayman Finance Ltd.:
2.38%, 01/15/20			4,194		4,193,735
2.20%, 01/15/21			4,190		4,174,729
3.88%, 01/15/27			12,569		12,622,042
Broadcom, Inc.:
3.13%, 04/15/21(b)			10,939		11,043,934
4.25%, 04/15/26(b)			13,640		14,088,853
Intel Corp., 4.80%, 10/01/41			2,955		3,726,783
KLA-Tencor Corp.:
4.10%, 03/15/29			5,379		5,934,474
5.00%, 03/15/49			3,560		4,383,223
Lam Research Corp.:
2.75%, 03/15/20			3,359		3,364,202
3.75%, 03/15/26			6,728		7,185,107
4.88%, 03/15/49			2,870		3,508,652
NVIDIA Corp., 3.20%, 09/16/26			12,346		12,980,314
NXP BV/NXP Funding LLC:
4.13%, 06/01/21(b)			11,201		11,492,543
4.63%, 06/15/22(b)			2,400		2,512,030
4.63%, 06/01/23(b)			9,245		9,840,947
5.55%, 12/01/28(b)			92		106,733
NXP BV/NXP Funding LLC/NXP USA, Inc.:
3.88%, 06/18/26(b)			861		906,727
4.30%, 06/18/29(b)			3,759		4,015,733
QUALCOMM, Inc.:
4.65%, 05/20/35			2,197		2,588,243
4.80%, 05/20/45			197		235,265
4.30%, 05/20/47			2,501		2,795,787
SK Hynix, Inc., 3.00%, 09/17/24			482		479,256
Texas Instruments, Inc.:
2.75%, 03/12/21			360		364,283
2.25%, 05/01/23			2,000		2,021,766
2.90%, 11/03/27			110		115,506
2.25%, 09/04/29			3,445		3,391,546
3.88%, 03/15/39			80		92,350
4.15%, 05/15/48			1,827		2,238,997
					155,155,614
Software — 0.6%
Autodesk, Inc., 3.50%, 06/15/27			12,151		12,554,346
CDK Global, Inc., 3.80%, 10/15/19			2,000		2,000,000
Microsoft Corp.:
3.50%, 02/12/35			7,483		8,269,868
4.20%, 11/03/35			730		873,167
3.45%, 08/08/36			15,965		17,647,958
3.70%, 08/08/46			14,512		16,516,461
Oracle Corp.:
2.50%, 10/15/22			853		865,687
3.40%, 07/08/24			1,375		1,449,909
2.65%, 07/15/26			6,339		6,472,288
3.25%, 11/15/27			2,096		2,220,101
3.25%, 05/15/30			360		382,190
4.30%, 07/08/34			427		494,808
3.90%, 05/15/35			5,205		5,747,055
3.85%, 07/15/36			59		64,807
3.80%, 11/15/37			1,136		1,236,776
5.38%, 07/15/40			2,990		3,888,302
4.13%, 05/15/45			1,477		1,672,130
4.00%, 07/15/46			5,625		6,289,449
SAP SE:
0.75%, 12/10/24	EUR		2,500		2,837,248
1.63%, 03/10/31			800		987,891
					92,470,441

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 55

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Specialty Retail — 0.2%
Home Depot, Inc.:
1.80%, 06/05/20	USD		201	$	200,729
2.13%, 09/15/26			1,695		1,684,195
3.90%, 12/06/28			1,658		1,862,857
2.95%, 06/15/29			2,230		2,340,246
5.88%, 12/16/36			4,119		5,696,385
5.95%, 04/01/41			514		735,832
4.20%, 04/01/43			895		1,051,452
4.88%, 02/15/44			930		1,198,878
4.25%, 04/01/46			201		240,717
3.90%, 06/15/47			462		528,935
3.50%, 09/15/56			1,602		1,704,376
Lowe’s Cos., Inc.:
4.25%, 09/15/44			99		106,441
4.38%, 09/15/45			4,380		4,839,707
3.70%, 04/15/46			100		100,698
4.05%, 05/03/47			1,707		1,822,081
					24,113,529
Technology Hardware, Storage & Peripherals — 0.3%
Apple Inc.:
1.00%, 11/10/22	EUR		7,100		8,031,783
3.00%, 02/09/24	USD		4,064		4,234,582
3.25%, 02/23/26			572		606,236
3.35%, 02/09/27			496		530,285
3.85%, 05/04/43			18,489		20,730,500
4.45%, 05/06/44			76		92,287
3.45%, 02/09/45			6,666		7,065,508
4.38%, 05/13/45			12		14,527
4.65%, 02/23/46			646		812,282
Dell International LLC/EMC Corp.:
5.88%, 06/15/21(b)			463		470,408
7.13%, 06/15/24(b)			356		375,224
8.35%, 07/15/46(b)			1,020		1,345,326
EMC Corp., 2.65%, 06/01/20			310		309,757
Hewlett Packard Enterprise Co.:
3.60%, 10/15/20			58		58,747
4.40%, 10/15/22			640		677,948
HP, Inc.:
3.75%, 12/01/20			73		74,198
6.00%, 09/15/41			460		525,142
Seagate HDD Cayman, 4.25%, 03/01/22			643		664,023
					46,618,763
Textiles, Apparel & Luxury Goods — 0.1%
LVMH Moet Hennessy Louis Vuitton SE:
0.38%, 05/26/22	EUR		1,442		1,591,203
0.13%, 02/28/23			6,000		6,588,667
					8,179,870
Thrifts & Mortgage Finance — 0.0%
Mongolian Mortgage Corp. Hfc LLC, 9.75%, 01/29/22	USD		800		789,750
Tobacco — 0.5%
Altria Group, Inc.:
1.00%, 02/15/23	EUR		1,845		2,044,898
4.40%, 02/14/26	USD		8,615		9,212,439
4.80%, 02/14/29			7,207		7,894,753
5.80%, 02/14/39			216		250,160
4.50%, 05/02/43			2,446		2,453,466
5.38%, 01/31/44			9,076		10,089,168
6.20%, 02/14/59			705		826,626
BAT Capital Corp.:
3.22%, 09/06/26			1,800		1,777,314
3.56%, 08/15/27			1,990		2,004,486
Philip Morris International, Inc.:
2.13%, 05/10/23			170		169,438
2.88%, 05/01/24			3,870		3,968,571
1.45%, 08/01/39	EUR		2,505		2,606,082

Security		Par (000)		Value
Tobacco (continued)
Philip Morris International, Inc.: (continued)
4.50%, 03/20/42	USD		1,110	$	1,232,230
3.88%, 08/21/42			58		59,301
Reynolds American, Inc.:
4.45%, 06/12/25			20,597		21,967,735
5.85%, 08/15/45			5,432		6,010,919
					72,567,586
Trading Companies & Distributors — 0.0%
Ashtead Capital, Inc.:
5.63%, 10/01/24(b)			2,016		2,076,480
4.13%, 08/15/25(b)			998		1,015,465
5.25%, 08/01/26(b)			330		350,212
Beacon Roofing Supply, Inc., 6.38%, 10/01/23			134		138,355
GATX Corp., 2.60%, 03/30/20			2,962		2,964,791
					6,545,303
Transportation Infrastructure — 0.0%
Adani Ports & Special Economic Zone Ltd.:
4.00%, 07/30/27			203		207,441
4.38%, 07/03/29			1,275		1,326,797
Aeropuertos Dominicanos Siglo XXI SA, 6.75%, 03/30/29(b)			706		739,314
Rumo Luxembourg Sarl, 5.88%, 01/18/25(b)			2,174		2,298,326
					4,571,878
Wireless Telecommunication Services — 0.2%
Digicel Group Two Ltd., 8.25%, 09/30/22(b)			3,096		628,304
Digicel Ltd.:
6.00%, 04/15/21(b)			2,289		1,611,599
6.75%, 03/01/23(b)			233		110,602
Millicom International Cellular SA, 6.63%, 10/15/26(b)			1,100		1,203,813
Sprint Communications, Inc., 7.00%, 03/01/20(b)			1,024		1,040,640
Sprint Corp.:
7.88%, 09/15/23			312		342,720
7.13%, 06/15/24			156		168,137
Sprint Spectrum Co. LLC/Sprint Spectrum Co. II LLC/Sprint Spectrum Co. III LLC, 3.36%, 03/20/23(b)			8,258		8,288,466
Vodafone Group PLC:
3.75%, 01/16/24			3,254		3,426,338
4.13%, 05/30/25			3,461		3,737,000
4.38%, 05/30/28			562		620,731
6.15%, 02/27/37			294		370,775
5.00%, 05/30/38			75		85,705
4.38%, 02/19/43			1,409		1,455,561
5.25%, 05/30/48			8,936		10,358,027
5.13%, 06/19/59			78		89,328
					33,537,746
Total Corporate Bonds — 37.1% (Cost: $5,583,382,567)					5,827,178,609
Floating Rate Loan Interests(a) — 2.1%
Air Freight & Logistics — 0.0%
XPO Logistics, Inc., Refinancing Term Loan (2018) (1 mo. LIBOR US + 2.000%, 0.000% Floor), 4.23%, 02/24/25			1,918		1,926,218
Airlines — 0.2%
Allegiant Travel Co., Class B Term Loan (3 mo. LIBOR US + 4.500%, 0.000% Floor), 6.71%, 02/05/24(c)			7,281		7,336,021

56 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		value
Airlines (continued)
Gol Luxco SA, Term Loan (6 mo. FIXED US + 6.500%, 0.000% Floor), 6.50%, 08/31/20(o)	USD		7,462	$	7,536,620
WestJet Airlines Ltd., Term Loan B, 3.00%, 08/07/26(p)			14,767		14,868,597
					29,741,238
Banks — 0.1%
Goldman Sachs Bank USA, Term Loan B (MFA), (3 mo. LIBOR US + 0.000%, 0.25% Floor), 4.12%, 09/17/20(c)			11,428		11,399,732
Building Products — 0.0%
Jeld-Wen, Inc., Term B-4 Loan (3 mo. LIBOR US + 2.000%, 0.000% Floor), 4.39%, 12/14/24			2,920		2,917,381
TAMKO Building Products LLC:
Initial Term Loan (1 mo. LIBOR US + 3.250%, 0.000% Floor), 5.29%, 05/29/26			3,169		3,165,205
Initial Term Loan (3 mo. LIBOR US + 3.250%, 0.000% Floor), 5.37%, 05/29/26			634		633,041
					6,715,627
Capital Markets — 0.2%
LSTAR Securities Financing Vehicle LLC, Loan (1 mo. LIBOR US + 2.000%, 0.000% Floor), 4.44%, 05/30/22(c)			24,036		24,035,578
Commercial Services & Supplies — 0.1%
Colorado Plaza, Term Loan, 2.90%, 05/15/20(c)(p)			8,600		8,600,000
KAR Auction Services, Inc., Tranche B-6 Term Loan, 2.25%, 09/19/26(p)			1,080		1,084,184
NRC U.S. Holding Co. LLC, Initial Term Loan (3 mo. LIBOR US + 5.250%, 1.000% Floor), 7.35%, 06/11/24			7,837		7,803,159
					17,487,343
Construction & Engineering — 0.0%
PLH Infrastructure Services, Inc., Term Loan (3 mo. LIBOR US + 6.000%, 0.000% Floor), 8.21%, 08/07/23(c)			2,717		2,689,625
Ply Gem Midco, Inc., Initial Term Loan (1 mo. LIBOR US + 3.750%, 0.000% Floor), 5.79%, 04/12/25			3,127		3,056,748
					5,746,373
Diversified Financial Services — 0.3%
18 Fremont Street Acquisition LLC, Term Loan (6 mo. LIBOR US + 8.000%, 1.500% Floor), 10.04%, 08/09/25(c)			12,000		12,000,273
BSREP II Houston Office 1HC Owner LLC, Mezzanine Loan (1 mo. LIBOR US + 2.500%, 0.000% Floor), 4.54%, 12/09/22			9,589		9,588,750
Goldman Sachs Lending Partners LLC, Term Loan A (MFA), (3 mo. LIBOR US + 0.000%, 0.25% Floor), 4.12%, 08/26/20(c)			4,793		4,781,436
Inmarsat PLC, Term Loan B, 4.50%, 09/23/26(p)			2,535		2,493,401
Intelsat Jackson Holdings SA:
Tranche B-3 Term Loan (1 mo. LIBOR US + 3.750%, 1.000% Floor), 5.80%, 11/27/23			1,275		1,277,792
Tranche B-4 Term Loan (1 mo. LIBOR US + 4.500%, 1.000% Floor), 6.55%, 01/02/24			1,458		1,474,123
RNTR-1 LLC (AKA Seer Sylvan), Initial Term Loan (1 mo. LIBOR US + 2.375%, 0.250% Floor), 4.40%, 12/20/21(c)			7,860		7,840,350

Security		Par (000)		value
Diversified Financial Services (continued)
Stars Group Holdings BV, USD Term Loan (3 mo. LIBOR US + 3.500%, 0.000% Floor), 5.60%, 07/10/25	USD		10,041	$	10,078,548
					49,534,673
Electronic Equipment, Instruments & Components — 0.0%
Robertshaw U.S. Holding Corp. (FKA Fox U.S. Bidco Corp.), Initial Term Loan (Second Lien) (1 mo. LIBOR US + 8.000%, 1.000% Floor), 10.06%, 02/28/26			1,795		1,537,723
Energy Equipment & Services — 0.1%
Bristow Group, Inc.:
Term Loan, 0.00%, 08/21/20(c)(p)			867		866,693
Term Loan (1 mo. LIBOR US + 7.000%, 2.500% Floor), 9.50%, 05/10/22(c)			1,738		1,728,848
PHI Group, Inc., Loan (1 mo. LIBOR US + 7.000%, 1.000% Floor), 9.04%, 09/04/24(c)			5,616		5,531,760
Pioneer Energy Services Corp. (FKA Pioneer Drilling Co.), Term Loan (1 mo. LIBOR US + 7.750%, 1.000% Floor), 9.80%, 11/08/22(c)			6,928		6,581,781
					14,709,082
Food Products — 0.0%
JBS USA Lux SA (FKA JBS USA LLC), New Term Loan (1 mo. LIBOR US + 2.500%, 0.000% Floor), 4.54%, 05/01/26			4,769		4,788,922
Health Care Providers & Services — 0.1%
Acadia Healthcare Co., Inc., Tranche B-4 Term Loan, 2.50%, 02/16/23(p)			7,638		7,643,958
Hotels, Restaurants & Leisure — 0.2%
DuPont Hotel Project Owner LLC, Loan (1 mo. LIBOR US + 2.500%, 1.000% Floor), 4.54%, 04/01/24(c)			12,000		12,000,000
MGM Growth Properties Operating Partnership LP, Term B Loan (1 mo. LIBOR US + 2.000%, 0.000% Floor), 4.04%, 03/21/25			12,310		12,328,499
PCI Gaming Authority, Term B Facility Loan (1 mo. LIBOR US + 3.000%, 0.000% Floor), 5.04%, 05/29/26			7,492		7,529,684
					31,858,183
Machinery — 0.0%
Gates Global LLC, Initial B-2 Dollar Term Loan (1 mo. LIBOR US + 2.750%, 1.000% Floor), 4.79%, 04/01/24			989		972,269
Media — 0.1%
Charter Communications Operating LLC (AKA CCO Safari LLC), Term A-2 Loan (1 mo. LIBOR US + 1.500%, 0.000% Floor), 3.55%, 03/31/23			7,078		7,051,147
Facebook Burlingame, Term Loan, 0.00%, 05/09/23(p)			5,628		5,627,840
Lamar Media Corp., Term B Loan, 1.75%, 03/14/25(p)			478		479,883
					13,158,870
Metals & Mining — 0.0%
Samarco Mineracao SA, Term Loan, 1.40%, 12/02/18(c)(f)(i)(p)			1,122		785,534

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 57

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Oil, Gas & Consumable Fuels — 0.2%
BCP Raptor II LLC, Initial Term Loan (1 mo. LIBOR US + 4.750%, 0.000% Floor), 6.79%, 11/03/25	USD		9,523	$	8,531,108
California Resources Corp.:
Initial Loan (1 mo. LIBOR US + 4.750%, 1.000% Floor), 6.79%, 12/31/22			5,498		4,870,293
Loan (1 mo. LIBOR US + 10.375%, 1.000% Floor), 12.42%, 12/31/21			7,760		6,736,689
CITGO Holding, Inc., Term Loan (1 mo. LIBOR US + 7.000%, 1.000% Floor), 9.04%, 08/01/23			1,128		1,147,740
Midcoast Energy LLC, Tranche B Term Loan (3 mo. LIBOR US + 5.500%, 0.000% Floor), 7.60%, 08/01/25			3,807		3,735,177
					25,021,007
Real Estate Management & Development — 0.2%
BRE Park Avenue Tower Owner LLC, Mezzanine A Loan (1 mo. LIBOR US + 2.053%, 0.000% Floor), 4.10%, 03/09/24			16,233		16,232,743
VICI Properties 1 LLC, Term B Loan (1 mo. LIBOR US + 2.000%, 0.000% Floor), 4.05%, 12/20/24			6,752		6,766,062
					22,998,805
Software — 0.0%
Interface Security Systems LLC, Initial Term Loan (1 mo. LIBOR US + 7.000%, 1.750% Floor), 9.04%, 08/07/23(c)			5,536		5,418,637
Technology Hardware, Storage & Peripherals — 0.1%
Aligned Energy Data Centers (SLC) Propco LLC, Term Loan (1 mo. LIBOR US + 3.500%, 0.000% Floor), 5.54%, 10/09/23			17,695		17,588,706
Thrifts & Mortgage Finance — 0.2%
Caliber Home Loans, Inc., Term Loan (1 mo. LIBOR US + 3.250%, 0.000% Floor), 5.35%, 04/24/21(c)			13,733		13,698,849
Roundpoint Mortgage Servicing Corp., Closing Date Term Loan (1 mo. LIBOR US + 3.375%, 0.000% Floor), 5.48%, 08/27/20(c)			17,937		17,960,255
					31,659,104
Trading Companies & Distributors — 0.0%
Foundation Building Materials Holding Company LLC, Term Loan (1 mo. LIBOR US + 3.000%, 0.000% Floor), 5.04%, 08/13/25			3,980		3,974,950
Total Floating Rate Loan Interests — 2.1% (Cost: $331,498,499)					328,702,532
Foreign Agency Obligations — 1.1%
Brazil — 0.1%
Petrobras Global Finance BV:
8.75%, 05/23/26			3,094		3,958,000
7.25%, 03/17/44			7,271		8,691,117
					12,649,117
China — 0.1%
Chalco Hong Kong Investment Co. Ltd., 4.88%, 09/07/21			775		796,189
Chengdu Xingcheng Investment Group Co. Ltd., 2.50%, 03/20/21	EUR		800		841,436

Security		Par (000)		Value
China (continued)
China Cinda Finance 2017 I Ltd., 4.75%, 02/21/29	USD		710	$	799,416
China Construction Bank Corp., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 1.880%), 4.25%, 02/27/29(j)			805		842,734
China Minmetals Corp., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 4.717%), 3.75%(j)(k)			339		339,000
China Railway Construction Corp. Ltd., 1.50%, 12/21/21(g)	CNH		4,000		552,379
Chinalco Capital Holdings Ltd.:
(5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 5.788%), 4.10%(j)(k)			735		735,735
4.25%, 04/21/22	USD		1,025		1,034,481
CNAC HK Finbridge Co. Ltd., 4.63%, 03/14/23			1,675		1,757,180
CNAC HK Synbridge Co. Ltd., 5.00%, 05/05/20			2,857		2,885,570
Franshion Brilliant Ltd., 4.25%, 07/23/29			1,000		991,840
Guangxi Financial Investment Group Co. Ltd., 5.75%, 01/23/21			500		479,325
HBIS Group Hong Kong Co. Ltd., 4.25%, 04/07/20			492		491,692
Huarong Finance 2019 Co. Ltd., 4.50%, 05/29/29			1,500		1,577,813
Hubei Science & Technology Investment Group Hong Kong Ltd., 4.38%, 03/05/21			255		256,913
Inner Mongolia High-Grade High Way Construction And Development Co. Ltd., 4.38%, 12/04/20			300		299,160
Leader Goal International Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 6.919%), 4.25%(j)(k)			700		711,156
Rongshi International Finance Ltd., 3.75%, 05/21/29			1,945		2,081,150
Sino-Ocean Land Treasure IV Ltd.:
5.25%, 04/30/22			480		490,773
4.75%, 08/05/29			715		692,049
Xi’an Municipal Infrastructure Construction Investment Group Corp. Ltd., 4.00%, 06/24/22			645		649,838
					19,305,829
Colombia — 0.1%
Ecopetrol SA, 7.38%, 09/18/43			2,035		2,724,992
Empresas Publicas de Medellin ESP, 4.25%, 07/18/29(b)			2,801		2,932,647
					5,657,639
France — 0.0%
RTE Reseau de Transport d’Electricite SADIR:
0.00%, 09/09/27	EUR		1,000		1,072,626
1.13%, 09/09/49			2,600		2,775,179
					3,847,805
Hong Kong — 0.0%
Joy Treasure Assets Holdings, Inc.:
4.50%, 03/20/29	USD		470		505,250
3.50%, 09/24/29			1,565		1,552,915
					2,058,165
India — 0.0%
Greenko Investment Co., 4.88%, 08/16/23			589		582,558
Oil India Ltd., 5.13%, 02/04/29			880		999,075
Power Finance Corp. Ltd.:
3.75%, 06/18/24			1,060		1,081,846
3.75%, 12/06/27			1,130		1,128,941

58 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
India (continued)
Power Finance Corp. Ltd.: (continued) 4.50%, 06/18/29	USD		893	$	932,906
REC Ltd., 4.63%, 03/22/28			670		703,081
					5,428,407
Indonesia — 0.0%
Indonesia Asahan Aluminium Persero PT, 5.71%, 11/15/23			1,925		2,122,914
Pertamina Persero PT, 4.70%, 07/30/49			625		648,438
Perusahaan Listrik Negara PT:
5.45%, 05/21/28			300		345,469
5.38%, 01/25/29			300		344,250
6.15%, 05/21/48			200		256,438
4.88%, 07/17/49			850		913,750
					4,631,259
Ireland — 0.0%
ESB Finance DAC, 3.49%, 01/12/24	EUR		2,915		3,659,390
Malaysia — 0.0%
1MDB Energy Ltd., 5.99%, 05/11/22	USD		1,500		1,578,750
Mexico — 0.5%
Petroleos Mexicanos:
6.38%, 02/04/21			5,442		5,680,088
(3 mo. LIBOR US + 3.650%), 5.79%, 03/11/22(a)			1,086		1,129,315
6.88%, 08/04/26			4,512		4,850,400
6.49%, 01/23/27(b)			1,156		1,205,130
6.50%, 03/13/27			42,323		43,966,986
5.35%, 02/12/28			6,035		5,774,741
7.69%, 01/23/50(b)			11,511		11,972,303
					74,578,963
Netherlands — 0.1%
Enexis Holding NV, 0.75%, 07/02/31	EUR		5,665		6,397,985
TenneT Holding BV:
1.25%, 10/24/33			950		1,124,686
1.50%, 06/03/39			2,960		3,606,285
					11,128,956
Norway — 0.1%
Telenor ASA:
0.00%, 09/25/23			3,400		3,721,408
1.75%, 05/31/34			4,660		5,723,145
					9,444,553
Saudi Arabia — 0.0%
SABIC Capital II BV, 4.00%, 10/10/23(b)	USD		1,864		1,957,200
Saudi Telecom Co., 3.89%, 05/13/29(b)			1,699		1,823,877
					3,781,077
Singapore — 0.0%
BOC Aviation Ltd., 3.00%, 09/11/29			2,000		1,974,940
South Africa — 0.1%
Eskom Holdings SOC Ltd.:
5.75%, 01/26/21(b)			2,400		2,424,000
6.75%, 08/06/23(b)			2,325		2,390,298
7.13%, 02/11/25(b)			656		675,680
					5,489,978
United Arab Emirates — 0.0%
Abu Dhabi Crude Oil Pipeline LLC, 4.60%, 11/02/47			1,100		1,278,750
United States — 0.0%
Citgo Holding, Inc., 9.25%, 08/01/24(b)			571		606,687
Total Foreign Agency Obligations — 1.1% (Cost: $161,812,461)					167,100,265

Security		Par (000)		Value
Foreign Government Obligations — 3.2%
Argentina — 0.1%
Bonos de la Nacion Argentina con Ajuste por CER, 4.00%, 03/06/20	ARS		75,811	$	473,186
Republic of Argentina:
3.38%, 10/12/20	CHF		385		187,934
4.63%, 01/11/23	USD		1,871		784,651
7.50%, 04/22/26			2,142		937,125
5.88%, 01/11/28			8,423		3,453,430
7.13%, 07/06/36			3,371		1,449,530
6.88%, 01/11/48			5,442		2,299,245
					9,585,101
Brazil — 0.1%
Federative Republic of Brazil, 4.50%, 05/30/29			8,556		8,916,956
China — 0.0%
People’s Republic of China, 3.30%, 07/04/23	CNH		3,500		496,612
Colombia — 0.5%
Colombian TES:
10.00%, 07/24/24	COP		61,158,000		21,154,517
6.25%, 11/26/25			44,752,400		13,380,968
Republic of Colombia, 3.88%, 04/25/27	USD		35,230		37,387,837
					71,923,322
Ecuador — 0.0%
Republic of Ecuador, 9.50%, 03/27/30(b)			5,775		5,841,413
Egypt — 0.1%
Arab Republic of Egypt:
15.90%, 07/02/24	EGP		13,550		877,306
7.50%, 01/31/27	USD		2,338		2,513,350
16.10%, 05/07/29	EGP		60,647		4,066,339
5.63%, 04/16/30	EUR		2,767		3,010,248
6.38%, 04/11/31(b)			2,459		2,786,567
6.88%, 04/30/40	USD		3,055		2,976,716
8.50%, 01/31/47			1,144		1,212,998
8.70%, 03/01/49(b)			989		1,061,939
8.70%, 03/01/49			1,155		1,240,181
					19,745,644
France — 0.3%
Republic of France, 1.75%, 05/25/66(b)	EUR		28,539		43,492,127
Hungary — 0.1%
Republic of Hungary, 5.38%, 03/25/24	USD		8,710		9,831,413
Indonesia — 0.3%
Perusahaan Penerbit SBSN Indonesia III, 4.40%, 03/01/28			550		601,563
Republic of Indonesia:
4.10%, 04/24/28			5,130		5,537,194
8.25%, 05/15/29	IDR		212,926,000		15,962,419
6.63%, 05/15/33			25,942,000		1,655,756
8.38%, 03/15/34			106,527,000		7,906,037
7.50%, 06/15/35			33,141,000		2,292,998
8.38%, 04/15/39			195,428,000		14,435,101
					48,391,068
Maldives — 0.0%
Republic of Maldives, 7.00%, 06/07/22	USD		775		732,375
Mexico — 0.9%
United Mexican States:
6.50%, 06/09/22	MXN		618,767		31,150,434
8.00%, 12/07/23			194,194		10,285,144
8.00%, 09/05/24			151,314		8,065,444
10.00%, 12/05/24			453,941		26,263,907
5.75%, 03/05/26			78,245		3,743,547

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 59

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security			Par (000)		Value
Mexico (continued)
United Mexican States: (continued)
4.15%, 03/28/27		USD		53,967	$	57,178,037
						136,686,513
Nigeria — 0.0%
Republic of Nigeria:
7.14%, 02/23/30				921		943,449
8.75%, 01/21/31				1,126		1,264,991
9.25%, 01/21/49				1,245		1,387,786
						3,596,226
Panama — 0.1%
Republic of Panama, 3.88%, 03/17/28				16,318		17,730,527
Peru — 0.1%
Republic of Peru, 4.13%, 08/25/27				14,574		16,354,761
Philippines — 0.1%
Republic of the Philippines, 3.00%, 02/01/28				22,148		23,211,990
Russia — 0.2%
Russian Federation, 8.50%, 09/17/31		RUB		2,049,275		35,331,391
South Africa — 0.1%
Republic of South Africa:
4.85%, 09/30/29		USD		2,446		2,439,885
5.75%, 09/30/49				5,698		5,679,482
						8,119,367
Sri Lanka — 0.0%
Republic of Sri Lanka, 6.85%, 03/14/24				425		433,500
Turkey — 0.0%
Republic of Turkey, 7.63%, 04/26/29				4,710		5,010,263
Ukraine — 0.0%
Ukraine Government, 9.75%, 11/01/28				5,666		6,494,653
United Arab Emirates — 0.1%
Emirate of Abu Dhabi:
2.13%, 09/30/24(b)				5,090		5,058,188
2.50%, 09/30/29				1,270		1,261,428
2.50%, 09/30/29(b)				5,723		5,684,370
3.13%, 09/30/49				1,925		1,867,238
						13,871,224
Uruguay — 0.1%
Republic of Uruguay, 4.38%, 10/27/27				14,750		16,211,533
Total Foreign Government Obligations — 3.2% (Cost: $501,726,845)						502,007,979
	Shares
Investment Companies — 0.3%
Communication Services Select Sector SPDR Fund				87,000		4,308,240
Invesco Senior Loan ETF(q)				68,385		1,544,817
VanEck Vectors Gold Miners ETF				160,590		4,289,359
VanEck Vectors JPMorgan EM Local Currency Bond ETF(q)				726,933		23,988,789
Health Care Select Sector SPDR Fund				47,000		4,236,110
iShares MSCI Emerging Markets ETF(v)				138,000		5,640,060
Total Investment Companies — 0.3% (Cost: $44,815,741)						44,007,375

Security		Par (000)		Value
Non-Agency Mortgage-Backed Securities — 5.2%
Collateralized Mortgage Obligations — 1.7%
American Home Mortgage Assets Trust:
Series 2006-3, Class 2A11, (12 mo. Federal Reserve Cumulative Average US + 0.940%), 3.42%, 10/25/46(a)	USD		937	$	843,084
Series 2006-4, Class 1A12, (1 mo. LIBOR US + 0.210%), 2.23%, 10/25/46(a)			2,697		1,878,073
Series 2006-5, Class A1, (12 mo. Federal Reserve Cumulative Average US + 0.920%), 3.37%, 11/25/46(a)			3,635		1,786,229
Series 2007-1, Class A1, (12 mo. Federal Reserve Cumulative Average US + 0.700%), 3.15%, 02/25/47(a)			829		513,268
APS Resecuritization Trust:
Series 2016-1, Class 1MZ, 4.02%, 07/31/57(b)(d)			7,026		2,641,803
Series 2016-3, Class 3A, (1 mo. LIBOR US + 2.850%), 4.87%, 09/27/46(a)(b)			5,877		5,961,408
Series 2016-3, Class 4A, (1 mo. LIBOR US + 2.600%), 4.62%, 04/27/47(a)(b)(c)			1,213		1,191,762
ARI Investments LLC, Series 2017-1, Class A, 0.00%, 01/06/25(c)(d)			2,978		2,977,624
Banc of America Funding Trust:
Series 2014-R2, Class 1C, 0.00%, 11/26/36(b)(d)			4,132		983,258
Series 2016-R2, Class 1A1, 4.70%, 05/01/33(b)(c)(d)			1,509		1,569,555
Bear Stearns Asset-Backed Securities I Trust, Series 2005-AC9, Class A5, 6.25%, 12/25/35(e)			248		246,303
Bear Stearns Mortgage Funding Trust:
Series 2006-SL1, Class A1, (1 mo. LIBOR US + 0.280%), 2.30%, 08/25/36(a)			1,565		1,560,143
Series 2007-AR2, Class A1, (1 mo. LIBOR US + 0.170%), 2.19%, 03/25/37(a)			478		448,785
Series 2007-AR3, Class 1A1, (1 mo. LIBOR US + 0.140%), 2.16%, 03/25/37(a)			718		692,585
Series 2007-AR4, Class 2A1, (1 mo. LIBOR US + 0.210%), 2.23%, 06/25/37(a)			778		758,026
BlackRock Capital Finance LP, Series 1997-R2, Class AP, 1.15%, 12/25/35(b)(d)(v)			3		3,056
Chase Mortgage Finance Trust, Series 2007-S6, Class 1A1, 6.00%, 12/25/37			26,102		18,925,066
Citicorp Mortgage Securities Trust:
Series 2007-9, Class 1A1, 6.25%, 12/25/37			2,015		1,790,492
Series 2008-2, Class 1A1, 6.50%, 06/25/38			6,538		5,693,875
Citigroup Mortgage Loan Trust, Series 2007-2, Class 2A, 6.00%, 11/25/36			16		16,396
Countrywide Alternative Loan Trust:
Series 2005-22T1, Class A1, (1 mo. LIBOR US + 0.350%), 2.37%, 06/25/35(a)			4,584		3,976,500
Series 2005-72, Class A3, (1 mo. LIBOR US + 0.600%), 2.62%, 01/25/36(a)			723		632,293
Series 2005-76, Class 2A1, (12 mo. Federal Reserve Cumulative Average US + 1.000%), 3.45%, 02/25/36(a)			881		832,162

60 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Collateralized Mortgage Obligations (continued)
Countrywide Alternative Loan Trust: (continued)
Series 2006-11CB, Class 3A1, 6.50%, 05/25/36	USD		1,879	$	1,458,940
Series 2006-15CB, Class A1, 6.50%, 06/25/36			435		325,576
Series 2006-23CB, Class 2A5, (1 mo. LIBOR US + 0.400%), 2.42%, 08/25/36(a)			6,126		2,034,511
Series 2006-OA14, Class 1A1, (12 mo. Federal Reserve Cumulative Average US + 1.730%), 4.18%, 11/25/46(a)			3,782		3,350,110
Series 2006-OA16, Class A4C, (1 mo. LIBOR US + 0.340%), 2.36%, 10/25/46(a)			4,212		2,559,263
Series 2006-OA21, Class A1, (1 mo. LIBOR US + 0.190%), 2.23%, 03/20/47(a)			9,975		8,629,243
Series 2006-OA6, Class 1A2, (1 mo. LIBOR US + 0.210%), 2.23%, 07/25/46(a)			3,594		3,515,863
Series 2006-OA8, Class 1A1, (1 mo. LIBOR US + 0.190%), 2.21%, 07/25/46(a)			545		530,861
Series 2006-OC10, Class 2A3, (1 mo. LIBOR US + 0.230%), 2.25%, 11/25/36(a)			1,661		1,371,295
Series 2006-OC7, Class 2A3, (1 mo. LIBOR US + 0.250%), 2.27%, 07/25/46(a)			2,414		1,981,660
Series 2007-3T1, Class 1A1, 6.00%, 04/25/37			403		281,860
Series 2007-OA3, Class 1A1, (1 mo. LIBOR US + 0.140%), 2.16%, 04/25/47(a)			1,175		1,119,591
Series 2007-OA3, Class 2A2, (1 mo. LIBOR US + 0.180%), 2.20%, 04/25/47(a)			133		40,739
Series 2007-OA8, Class 2A1, (1 mo. LIBOR US + 0.180%), 2.20%, 06/25/47(a)			411		329,802
Series 2007-OH2, Class A2A, (1 mo. LIBOR US + 0.240%), 2.26%, 08/25/47(a)			545		446,217
Countrywide Home Loan Mortgage Pass-Through Trust:
Series 2004-29, Class 1A1, (1 mo. LIBOR US + 0.540%), 2.56%, 02/25/35(a)			283		275,127
Series 2006-OA4, Class A1, (12 mo. Federal Reserve Cumulative Average US + 0.960%), 3.41%, 04/25/46(a)			1,513		731,765
Series 2006-OA5, Class 3A1, (1 mo. LIBOR US + 0.200%), 2.22%, 04/25/46(a)			750		714,457
Series 2007-15, Class 2A2, 6.50%, 09/25/37			10,616		7,837,329
Credit Suisse Commercial Mortgage Trust:
Series 19-JR1, Class A1, 4.10%, 09/27/66(b)(d)			42,621		42,713,298
Series 2009-12R, Class 3A1, 6.50%, 10/27/37(b)			8,103		4,600,202
Series 2009-5R, Class 4A4, 4.25%, 06/25/36(b)(d)			2,005		1,860,117
Series 2014-11R, Class 16A1, 4.00%, 09/27/47(b)(d)			1,771		1,800,740
Series 2014-4R, Class 16A3, (1 mo. LIBOR US + 0.200%), 2.35%, 02/27/36(a)(b)(c)			815		757,676
Series 2014-9R, Class 9A1, (1 mo. LIBOR US + 0.120%), 2.27%, 08/27/36(a)(b)			1,535		1,399,352
Series 2015-6R, Class 5A1, (1 mo. LIBOR US + 0.180%), 2.51%, 03/27/36(a)(b)			132		131,428

Security		Par (000)		Value
Collateralized Mortgage Obligations (continued)
Credit Suisse Commercial Mortgage Trust: (continued)
Series 2015-6R, Class 5A2, (1 mo. LIBOR US + 0.180%), 2.51%, 03/27/36(a)(b)	USD		2,721	$	2,096,235
Series 2019-RPL4, Class A1, 3.83%, 08/26/58(b)			6,281		6,352,784
CSFB Mortgage-Backed Pass-Through Certificates, Series 2005-10, Class 10A1, (1 mo. LIBOR US + 1.350%), 3.37%, 11/25/35(a)			1,306		395,188
Deutsche Alt-A Securities Mortgage Loan Trust, Series 2007-OA4, Class A2A, (1 mo. LIBOR US + 0.170%), 2.19%, 08/25/47(a)			1,437		1,011,708
Deutsche Alt-A Securities, Inc., Series 2007-RS1, Class A2, (1 mo. LIBOR US + 0.500%), 2.64%, 01/27/37(a)(b)			102		98,839
Deutsche Alt-B Securities Mortgage Loan Trust:
Series 2006-AB3, Class A3, 6.51%, 07/25/36(d)			533		499,615
Series 2006-AB3, Class A8, 6.36%, 07/25/36(d)			340		318,603
GreenPoint Mortgage Funding Trust, Series 2006-AR2, Class 4A1, (12 mo. Federal Reserve Cumulative Average US + 2.000%), 4.45%, 03/25/36(a)			954		952,904
GSR Mortgage Loan Trust:
Series 2006-OA1, Class 1A1, (1 mo. LIBOR US + 0.220%), 2.24%, 08/25/46(a)			18,537		7,314,934
Series 2007-1F, Class 2A4, 5.50%, 01/25/37			306		338,002
HarborView Mortgage Loan Trust, Series 2007-4, Class 2A2, (1 mo. LIBOR US + 0.250%), 2.31%, 07/19/47(a)			818		749,507
Impac CMB Trust:
Series 2004-11, Class 1A2, (1 mo. LIBOR US + 0.520%), 2.54%, 03/25/35(a)			1,477		1,461,972
Series 2005-6, Class 1A1, (1 mo. LIBOR US + 0.500%), 2.52%, 10/25/35(a)			1,101		1,085,536
IndyMac INDX Mortgage Loan Trust:
Series 2007-AR19, Class 3A1, 3.72%, 09/25/37(d)			3,443		2,470,456
Series 2007-FLX5, Class 2A2, (1 mo. LIBOR US + 0.240%), 2.26%, 08/25/37(a)			1,172		1,046,631
JPMorgan Alternative Loan Trust:
Series 2007-A1, Class 1A4, (1 mo. LIBOR US + 0.210%), 2.23%, 03/25/37(a)			1,772		1,704,701
Series 2007-A2, Class 2A1, 4.17%, 05/25/37(d)			409		373,037
Legacy Mortgage Asset Trust, Series 2019-SL1, Class A 4.00%, 12/25/54(b)(d)			10,141		10,151,528
Lehman XS Trust, Series 2007-20N, Class A1, (1 mo. LIBOR US + 1.150%), 3.17%, 12/25/37(a)			1,090		1,078,383
LSTAR Securities Investment Trust:
Series 2019-1, Class A1, (1 mo. LIBOR US + 1.700%), 3.79%, 03/01/24(a)(b)			3,632		3,634,163

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 61

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Collateralized Mortgage Obligations (continued)
LSTAR Securities Investment Trust: (continued)
Series 2019-2, Class A1, (1 mo. LIBOR US + 1.500%), 3.59%, 04/01/24(a)(b)	USD		4,589	$	4,589,430
MASTR Resecuritization Trust, Series 2008-3, Class A1, 2.58%, 08/25/37(b)(c)(d)			1,284		1,014,372
MCM Trust:
Series 2018-NPL1, Class A, 4.00%, 06/25/58(b)(c)(d)			3,688		3,691,695
Series 2018-NPL1, Class B, 0.00%, 06/25/58(b)(c)(d)			9,920		1,388,802
Series 2018-NPL2, Class A, 4.00%, 10/25/28(b)(c)(e)			10,984		11,066,357
Series 2018-NPL2, Class B, 0.00%, 10/25/28(b)(c)			17,060		3,775,428
Merrill Lynch Alternative Note Asset Trust, Series 2007-OAR2, Class A2, (1 mo. LIBOR US + 0.210%), 2.23%, 04/25/37(a)			2,651		2,322,426
Merrill Lynch Mortgage Investors Trust, Series 2006-A3, Class 6A1, 4.10%, 05/25/36(d)			1,583		1,475,583
Mortgage Loan Resecuritization Trust, Series 2009-RS1, Class A85, (1 mo. LIBOR US + 0.340%), 2.44%, 04/16/36(a)(b)			8,546		7,410,806
New Residential Mortgage Loan Trust:
Series 2019-2A, Class A1, 4.25%, 12/25/57(b)(d)			2,327		2,424,922
Series 2019-RPL1, Class A1, 4.33%, 02/26/24(b)(e)			6,899		6,945,861
Nomura Asset Acceptance Corp. Alternative Loan Trust:
Series 2001-R1A, Class A, 7.00%, 02/19/30(b)(d)			502		514,539
Series 2006-AF1, Class 1A4, 6.63%, 05/25/36(e)			606		229,630
Series 2007-2, Class A4, (1 mo. LIBOR US + 0.420%), 2.44%, 06/25/37(a)			453		374,648
Paragon Mortgages No. 13 PLC, Series 13X, Class A2C, (3 mo. LIBOR US + 0.180%), 2.48%, 01/15/39(a)			336		318,398
RALI Trust, Series 2007-QH9, Class A1, 3.65%, 11/25/37(d)			887		827,885
Reperforming Loan REMIC Trust:
Series 2005-R2, Class 1AF1, (1 mo. LIBOR US + 0.340%), 2.36%, 06/25/35(a)(b)			529		507,037
Series 2005-R3, Class AF, (1 mo. LIBOR US + 0.400%), 2.42%, 09/25/35(a)(b)			176		161,806
Seasoned Credit Risk Transfer Trust:
Series 2017-3, Class M2, 4.75%, 07/25/56(b)(d)			1,550		1,560,589
Series 2018-1, Class BX, 5.32%, 05/25/57(d)			553		289,441
Series 2018-1, Class M, 4.75%, 05/25/57(d)			500		509,429
Series 2018-3, Class M, 4.75%, 08/25/57(b)(d)			2,700		2,750,205
STACR Trust, Series 2018-DNA2, Class M2, (1 mo. LIBOR US + 2.150%), 4.17%, 12/25/30(a)(b)			1,430		1,442,298
Structured Adjustable Rate Mortgage Loan Trust, Series 2006-3, Class 4A, 4.03%, 04/25/36(d)			1,024		856,009
Structured Asset Mortgage Investments II Trust: Series 2006-AR4, Class 3A1, (1 mo. LIBOR US + 0.190%), 2.21%, 06/25/36(a)			3,066		2,983,334

Security		Par (000)		Value
Collateralized Mortgage Obligations (continued)
Structured Asset Mortgage Investments II Trust: (continued)
Series 2006-AR5, Class 2A1, (1 mo. LIBOR US + 0.210%), 2.23%, 05/25/46(a)	USD		616	$	533,588
Thornburg Mortgage Securities Trust, Series 2007-3, Class 4A1, (12 mo. LIBOR US + 1.250%), 3.28%, 06/25/47(a)			440		403,665
Washington Mutual Mortgage Pass-Through Certificates, Series 2006-1, Class 4CB, 6.50%, 02/25/36			1,546		1,383,998
Washington Mutual Mortgage Pass-Through Certificates Trust:
Series 2005-AR2, Class B1, (1 mo. LIBOR US + 0.530%), 2.55%, 01/25/45(a)			622		480,863
Series 2006-4, Class 1A1, 6.00%, 04/25/36			4,566		4,300,022
Series 2006-4, Class 3A1, 6.50%, 05/25/36(e)			1,525		1,381,590
Series 2006-4, Class 3A5, 6.35%, 05/25/36(e)			591		535,695
Total Collateralized Mortgage Obligations — 1.7% (Cost: $263,728,031)					258,303,845
Commercial Mortgage-Backed Securities — 3.2%
1211 Avenue of the Americas Trust, Series 2015-1211, Class D, 4.28%, 08/10/35(b)(d)			660		700,942
245 Park Avenue Trust:
Series 2017-245P, Class D, 3.66%, 06/05/37(b)(d)			480		501,290
Series 2017-245P, Class E, 3.78%, 06/05/37(b)(d)			1,699		1,694,280
280 Park Avenue Mortgage Trust:
Series 2017-280P, Class D, (1 mo. LIBOR US + 1.537%), 3.56%, 09/15/34(a)(b)			2,920		2,925,453
Series 2017-280P, Class E, (1 mo. LIBOR US + 2.119%), 4.15%, 09/15/34(a)(b)			5,835		5,853,159
Series 2017-280P, Class F, (1 mo. LIBOR US + 2.827%), 4.86%, 09/15/34(a)(b)			630		632,748
Americold LLC, Series 2010-ARTA, Class C, 6.81%, 01/14/29(b)			700		727,319
AOA Mortgage Trust, Series 2015-1177, Class C, 3.11%, 12/13/29(b)(d)			1,340		1,348,547
AREIT Trust, Series 2018-CRE1, Class A, (1 mo. LIBOR US + 0.850%), 2.88%, 02/14/35(a)(b)			47		47,180
Ashford Hospitality Trust, Series 2018-ASHF, Class D, (1 mo. LIBOR US + 2.100%), 4.13%, 04/15/35(a)(b)			1,791		1,795,467
Asset Securitization Corp., Series 1997-D5, Class B2, 6.93%, 02/14/43			75		74,814
Atrium Hotel Portfolio Trust:
Series 2017-ATRM, Class D, (1 mo. LIBOR US + 1.950%), 3.98%, 12/15/36(a)(b)			4,840		4,846,008
Series 2017-ATRM, Class E, (1 mo. LIBOR US + 3.050%), 5.08%, 12/15/36(a)(b)			910		913,347
Series 2018-ATRM, Class E, (1 mo. LIBOR US + 3.400%), 5.43%, 06/15/35(a)(b)			1,640		1,649,207
Aventura Mall Trust, Series 2013-AVM, Class D, 3.74%, 12/05/32(b)(d)			300		303,525
Banc of America Commercial Mortgage Trust, Series 2007-1, Class AMFX, 5.48%, 01/15/49(d)			158		157,790

62 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Banc of America Merrill Lynch Commercial Mortgage Securities Trust:
Series 2015-200P, Class F, 3.72%, 04/14/33(b)(d)	USD		1,241	$	1,252,796
Series 2016-ISQ, Class C, 3.73%, 08/14/34(b)(d)			445		467,536
Series 2016-ISQ, Class E, 3.73%, 08/14/34(b)(d)			6,140		6,152,426
Series 2017-SCH, Class BF, (1 mo. LIBOR US + 1.400%), 3.43%, 11/15/33(a)(b)			2,170		2,162,275
Series 2017-SCH, Class CL, (1 mo. LIBOR US + 1.500%), 3.53%, 11/15/32(a)(b)			970		969,893
Series 2017-SCH, Class DL, (1 mo. LIBOR US + 2.000%), 4.03%, 11/15/32(a)(b)			1,930		1,929,788
Series 2018-DSNY, Class D, (1 mo. LIBOR US + 1.700%), 3.73%, 09/15/34(a)(b)			3,275		3,285,269
Bancorp Commercial Mortgage Trust, Series 2018-CR3, Class A, (1 mo. LIBOR US + 0.850%), 2.88%, 01/15/33(a)(b)			1,644		1,639,520
BANK, Series 2019-BN19, Class C, 4.17%, 08/15/61(d)			1,540		1,659,037
Barclays Commercial Mortgage Trust:
Series 2015-STP, Class E, 4.43%, 09/10/28(b)(d)			100		99,044
Series 2018-TALL, Class A, (1 mo. LIBOR US + 0.722%), 2.75%, 03/15/37(a)(b)			918		915,716
Series 2018-TALL, Class D, (1 mo. LIBOR US + 1.449%), 3.48%, 03/15/37(a)(b)			1,120		1,119,997
Series 2019-C3, Class C, 4.18%, 05/15/52			1,514		1,631,225
Series 2019-C3, Class D, 3.00%, 05/15/52(b)			1,189		1,112,565
Bayview Commercial Asset Trust:
Series 2005-2A, Class A1, (1 mo. LIBOR US + 0.310%), 2.33%, 08/25/35(a)(b)			1,299		1,246,697
Series 2005-4A, Class A1, (1 mo. LIBOR US + 0.300%), 2.32%, 01/25/36(a)(b)			321		309,215
Series 2005-4A, Class A2, (1 mo. LIBOR US + 0.390%), 2.41%, 01/25/36(a)(b)			90		87,536
Series 2005-4A, Class M1, (1 mo. LIBOR US + 0.450%), 2.47%, 01/25/36(a)(b)			241		232,370
Series 2006-1A, Class A2, (1 mo. LIBOR US + 0.360%), 2.38%, 04/25/36(a)(b)			325		313,006
Series 2006-3A, Class A1, (1 mo. LIBOR US + 0.250%), 2.27%, 10/25/36(a)(b)			593		567,377
Series 2006-3A, Class A2, (1 mo. LIBOR US + 0.300%), 2.32%, 10/25/36(a)(b)			413		396,471
Series 2006-4A, Class A1, (1 mo. LIBOR US + 0.230%), 2.25%, 12/25/36(a)(b)			850		819,951
Series 2007-6A, Class A4A, (1 mo. LIBOR US + 1.500%), 3.52%, 12/25/37(a)(b)			1,980		1,883,173
BBCMS Mortgage Trust, Series 2018-CHRS, Class E, 4.41%, 08/05/38(b)(d)			980		913,276
BBCMS Trust, Series 2015-SRCH, Class A1, 3.31%, 08/10/35(b)			2,730		2,842,741
BB-UBS Trust, Series 2012-SHOW, Class E, 4.03%, 11/05/36(b)(d)			790		795,591
Bear Stearns Commercial Mortgage Securities Trust:
Series 2005-PWR7, Class B, 5.21%, 02/11/41(d)			888		885,657
Series 2007-T26, Class AM, 5.51%, 01/12/45(d)			768		766,064

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Benchmark Mortgage Trust:
Series 2018-B3, Class D, 3.06%, 04/10/51(b)(d)	USD		210	$	197,885
Series 2019-B10, Class 3CCA, 4.03%, 03/15/62(b)(d)			4,860		5,159,376
Series 2019-B13, Class A4, 2.95%, 08/15/57			1,927		1,999,624
BHMS, Series 2018-ATLS, Class A, (1 mo. LIBOR US + 1.250%), 3.28%, 07/15/35(a)(b)			7,050		7,049,958
BWAY Mortgage Trust:
Series 2013-1515, Class A2, 3.45%, 03/10/33(b)			2,920		3,093,575
Series 2013-1515, Class D, 3.63%, 03/10/33(b)			1,400		1,449,745
Series 2013-1515, Class E, 3.72%, 03/10/33(b)			250		258,038
Series 2013-1515, Class F, 4.06%, 03/10/33(b)(d)			250		255,356
BX Commercial Mortgage Trust, Series 2018-IND, Class H, (1 mo. LIBOR US + 3.000%), 5.03%, 11/15/35(a)(b)			12,313		12,340,148
BXP Trust:
Series 2017-CC, Class D, 3.67%, 08/13/37(b)(d)			750		771,831
Series 2017-CC, Class E, 3.67%, 08/13/37(b)(d)			1,450		1,456,283
Series 2017-GM, Class D, 3.54%, 06/13/39(b)(d)			590		610,308
Series 2017-GM, Class E, 3.54%, 06/13/39(b)(d)			1,240		1,240,549
CAMB Commercial Mortgage Trust, Series 2019-LIFE, Class D, (1 mo. LIBOR US + 1.750%), 3.78%, 12/15/37(a)(b)			6,011		6,040,480
CCRESG Commercial Mortgage Trust, Series 2016-HEAT, Class D, 5.67%, 04/10/29(b)(d)			560		572,587
CFCRE Commercial Mortgage Trust:
Series 2016-C3, Class A3, 3.87%, 01/10/48	.		410		444,205
Series 2018-TAN, Class C, 5.29%, 02/15/33(b)			1,160		1,242,209
CFK Trust, Series 2019-FAX, Class D, 4.64%, 01/15/39(b)(d)			2,643		3,027,291
CGBAM Commercial Mortgage Trust:
Series 2015-SMRT, Class E, 3.91%, 04/10/28(b)(d)			1,880		1,888,428
Series 2015-SMRT, Class F, 3.91%, 04/10/28(b)(d)			230		231,031
CGDBB Commercial Mortgage Trust:
Series 2017-BIOC, Class A, (1 mo. LIBOR US + 0.790%), 2.82%, 07/15/32(a)(b)			4,330		4,329,994
Series 2017-BIOC, Class D, (1 mo. LIBOR US + 1.600%), 3.63%, 07/15/32(a)(b)			4,760		4,760,006
Series 2017-BIOC, Class E, (1 mo. LIBOR US + 2.150%), 4.18%, 07/15/32(a)(b)			7,000		7,000,003
CHC Commercial Mortgage Trust, Series 2019-CHC, Class B, (1 mo. LIBOR US + 1.500%), 3.53%, 06/15/34(a)(b)			7,293		7,302,132
Citigroup Commercial Mortgage Trust:
Series 2014-GC19, Class C, 5.26%, 03/10/47(d)			440		477,320
Series 2015-SHP2, Class B, (1 mo. LIBOR US + 1.850%), 3.88%, 07/15/27(a)(b)			3,470		3,474,263

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 63

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Citigroup Commercial Mortgage Trust: (continued)
Series 2015-SHP2, Class F, (1 mo. LIBOR US + 5.200%), 7.23%, 07/15/27(a)(b)	USD		370	$	370,248
Series 2016-C1, Class C, 5.12%, 05/10/49(d)			1,290		1,435,157
Series 2016-C1, Class D, 5.12%, 05/10/49(b)(d)			450		471,046
Series 2016-GC37, Class C, 5.09%, 04/10/49(d)			640		697,798
Series 2016-P3, Class C, 5.00%, 04/15/49(d)			120		131,593
Series 2016-P3, Class D, 2.80%, 04/15/49(b)(d)			137		120,895
Series 2017-C4, Class A4, 3.47%, 10/12/50			1,220		1,312,279
Series 2019-PRM, Class E, 4.89%, 05/10/36(b)			4,801		4,973,498
Series 2019-SMRT, Class D, 4.90%, 01/10/24(b)(d)			7,200		7,664,076
Series 2019-SMRT, Class E, 4.90%, 01/10/24(b)(d)			419		435,554
Citigroup/Deutsche Bank Commercial Mortgage Trust:
Series 2006-CD3, Class AM, 5.65%, 10/15/48			3,229		3,320,574
Series 2017-CD3, Class A4, 3.63%, 02/10/50			850		920,928
Series 2017-CD4, Class A4, 3.51%, 05/10/50(d)			50		53,623
CLNS Trust, Series 2017-IKPR, Class E, (1 mo. LIBOR US + 3.500%), 5.55%, 06/11/32(a)(b)			1,554		1,554,964
Commercial Mortgage Pass-Through Certificates:
Series 2005-C6, Class F, 5.91%, 06/10/44(b)(d)			380		386,958
Series 2014-CR14, Class A4, 4.24%, 02/10/47(d)			855		922,341
Series 2014-CR15, Class C, 4.90%, 02/10/47(d)			260		282,222
Series 2014-CR16, Class A4, 4.05%, 04/10/47			4,806		5,160,312
Series 2014-CR17, Class A5, 3.98%, 05/10/47			2,642		2,836,713
Series 2014-CR18, Class A4, 3.55%, 07/15/47			390		408,912
Series 2014-CR19, Class A5, 3.80%, 08/10/47			1,391		1,488,397
Series 2014-CR21, Class C, 4.58%, 12/10/47(d)			1,010		1,073,664
Series 2015-CR23, Class CMC, 3.81%, 05/10/48(b)(d)			210		210,540
Series 2015-CR23, Class CMD, 3.81%, 05/10/48(b)(d)			10,150		10,166,654
Series 2015-CR23, Class CME, 3.81%, 05/10/48(b)(d)			2,600		2,599,442
Series 2015-CR24, Class A5, 3.70%, 07/10/25			1,370		1,471,708
Series 2015-CR25, Class A4, 3.76%, 08/10/48			3,505		3,773,870
Series 2015-CR25, Class C, 4.70%, 08/10/48(d)			1,010		1,066,576
Series 2015-LC19, Class A4, 3.18%, 02/10/48			1,785		1,865,101
Series 2015-LC19, Class C, 4.39%, 02/10/48(d)			450		476,563

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Commercial Mortgage Pass-Through Certificates: (continued)
Series 2015-LC19, Class D, 2.87%, 02/10/48(b)	USD		676	$	645,517
Series 2015-LC21, Class C, 4.44%, 07/10/48(d)			1,600		1,694,072
Series 2017-COR2, Class A3, 3.51%, 09/10/50			1,180		1,266,455
Series 2017-COR2, Class D, 3.00%, 09/10/50 (b)			860		812,766
Series 2018-HCLV, Class B, (1 mo. LIBOR US + 1.400%), 3.43%, 09/15/33(a)(b)			1,420		1,416,886
Commercial Mortgage Trust:
Series 2013-GAM, Class A2, 3.37%, 02/10/28(b)			1,656		1,666,524
Series 2014-LC15, Class A4, 4.01%, 04/10/47			2,350		2,519,462
Series 2014-UBS4, Class C, 4.80%, 08/10/47(d)			2,395		2,507,856
Series 2015-CR23, Class A4, 3.50%, 05/10/48			810		860,341
Series 2015-LC23, Class A4, 3.77%, 10/10/48			1,040		1,123,720
Series 2016-667M, Class D, 3.28%, 10/10/36(b)(d)			630		638,651
Core Industrial Trust:
Series 2015-CALW, Class A, 3.04%, 02/10/34(b)			1,802		1,840,797
Series 2015-CALW, Class G, 3.98%, 02/10/34(b)(d)			1,971		2,001,891
Series 2015-TEXW, Class A, 3.08%, 02/10/34(b)			2,948		3,012,869
Series 2015-TEXW, Class D, 3.98%, 02/10/34(b)(d)			1,330		1,355,919
Series 2015-TEXW, Class E, 3.98%, 02/10/34(b)(d)			250		253,062
Series 2015-TEXW, Class F, 3.98%, 02/10/34(b)(d)			5,869		5,894,843
Credit Suisse Commercial Mortgage Trust:
Series 2015-GLPB, Class A, 3.64%, 11/15/34(b)			2,305		2,415,795
Series 2017-PFHP, Class A, (1 mo. LIBOR US + 0.950%), 2.98%, 12/15/30(a)(b)			900		898,876
Series 2017-TIME, Class A, 3.65%, 11/13/39(b)			850		902,635
Credit Suisse First Boston Mortgage Securities Corp., Series 2005-C3, Class C, 4.95%, 07/15/37(d)			1		1,221
CSAIL Commercial Mortgage Trust:
Series 2015-C2, Class A4, 3.50%, 06/15/57			1,160		1,229,426
Series 2018-C14, Class C, 5.06%, 11/15/51(d)			1,250		1,414,476
Series 2019-C15, Class A4, 4.05%, 03/15/52			3,683		4,131,030
Series 2019-C15, Class C, 5.15%, 03/15/52(d)			2,755		3,127,172
Series 2019-C15, Class D, 3.00%, 03/15/52(b)			1,285		1,178,268
Series 2019-C16, Class A3, 3.33%, 06/15/52			2,650		2,821,963
Series 2019-C16, Class C, 4.24%, 06/15/52(d)			3,600		3,854,826
Series 2019-C17, Class C, 3.93%, 09/15/52			4,458		4,634,289

64 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
CSAIL Commercial Mortgage Trust: (continued)
Series 2019-C17, Class D, 2.50%, 09/15/52(b)	USD		3,641	$	3,112,056
DBGS Mortgage Trust, Series 2019-1735, Class F, 4.33%, 04/10/37(b)(d)			1,144		1,129,050
Deutsche Bank JPMorgan Mortgage Trust, Series 2016-C1, Class A4, 3.28%, 02/10/26	.		1,430		1,512,049
Deutsche Bank UBS Mortgage Trust:
Series 2017-BRBK, Class A, 3.45%, 10/10/34(b)			2,540		2,668,612
Series 2017-BRBK, Class D, 3.65%, 10/10/34(b)(d)			1,800		1,852,558
Series 2017-BRBK, Class E, 3.65%, 10/10/34(b)(d)			4,290		4,325,868
Series 2017-BRBK, Class F, 3.65%, 10/10/34(b)(d)			880		875,373
Eleven Madison Trust Mortgage Trust, Series 2015-11MD, Class A, 3.67%, 09/10/35(b)(d)			1,190		1,274,295
Exantas Capital Corp. Ltd., Series 2019-RSO7, Class AS, (1 mo. LIBOR US + 1.500%), 3.53%, 04/15/36(a)(b)			3,495		3,498,778
FREMF Mortgage Trust:
Series 2016-K54, Class B, 4.19%, 04/25/48(b)(d)			1,280		1,362,548
Series 2017-K64, Class B, 4.12%, 05/25/50(b)(d)			766		824,928
Series 2017-KGX1, Class BFX, 3.71%, 10/25/27(b)(d)			1,190		1,192,332
Series 2018-K74, Class B, 4.23%, 02/25/51(b)(d)			120		129,464
Series 2018-K77, Class B, 4.16%, 05/25/51(b)(d)			770		834,381
Series 2018-K80, Class B, 4.37%, 08/25/50(b)(d)			1,510		1,643,608
FRESB Mortgage Trust:
Series 2018-SB52, Class A10F, 3.48%, 06/25/28(d)			2,446		2,572,207
Series 2018-SB53, Class A10F, 3.66%, 06/25/28(d)			1,456		1,571,194
GPMT Ltd., Series 2018-FL1, Class A, (1 mo. LIBOR US + 0.900%), 2.94%, 11/21/35(a)(b)			1,759		1,757,497
Grace Mortgage Trust, Series 2014-GRCE, Class F, 3.71%, 06/10/28(b)(d)			1,662		1,677,104
GS Mortgage Securities Corp Trust:
Series 2017-500K, Class D, (1 mo. LIBOR US + 1.300%), 3.33%, 07/15/32(a)(b)			230		230,072
Series 2017-500K, Class E, (1 mo. LIBOR US + 1.500%), 3.53%, 07/15/32(a)(b)			480		480,599
Series 2017-500K, Class F, (1 mo. LIBOR US + 1.800%), 3.83%, 07/15/32(a)(b)			549		550,373
Series 2017-500K, Class G, (1 mo. LIBOR US + 2.500%), 4.53%, 07/15/32(a)(b)			170		168,620
GS Mortgage Securities Corp. II:
Series 2005-ROCK, Class A, 5.37%, 05/03/32(b)			2,750		3,165,696
Series 2013-KING, Class E, 3.55%, 12/10/27(b)(d)			2,990		2,984,392
GS Mortgage Securities Corp. Trust:
Series 2017-GPTX, Class A, 2.86%, 05/10/34(b)			2,290		2,299,209

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
GS Mortgage Securities Corp. Trust: (continued)
Series 2018-HULA, Class D, (1 mo. LIBOR US + 1.800%), 3.83%, 07/15/25(a)(b)	USD		1,204	$	1,207,350
Series 2019-BOCA, Class A, (1 mo. LIBOR US + 1.200%), 3.23%, 06/15/38(a)(b)			1,431		1,431,891
Series 2019-SOHO, Class E, (1 mo. LIBOR US + 1.875%), 3.90%, 06/15/36(a)(b)			4,020		4,011,170
GS Mortgage Securities Trust:
Series 2010-C1, Class A1, 3.68%, 08/10/43(b)			70		70,268
Series 2014-GC20, Class B, 4.53%, 04/10/47(d)			140		150,393
Series 2014-GC24, Class A5, 3.93%, 09/10/47			882		949,462
Series 2015-590M, Class E, 3.93%, 10/10/35(b)(d)			1,410		1,421,848
Series 2015-GC28, Class B, 3.98%, 02/10/48			680		719,330
Series 2015-GC32, Class C, 4.56%, 07/10/48(d)			1,370		1,466,500
Series 2015-GS1, Class A3, 3.73%, 11/10/48			670		725,209
Series 2016-RENT, Class C, 4.20%, 02/10/29(b)(d)			1,070		1,083,826
Series 2017-GS6, Class A3, 3.43%, 05/10/50			1,290		1,380,186
Series 2017-GS7, Class A4, 3.43%, 08/10/50			3,001		3,199,474
Series 2017-GS7, Class D, 3.00%, 08/10/50(b)			530		506,681
Series 2017-GS7, Class E, 3.00%, 08/10/50(b)			180		167,987
GSCG Trust, Series 2019-600C, Class F, 4.12%, 09/06/34(b)(d)			1,950		1,941,437
HMH Trust, Series 2017-NSS, Class A, 3.06%, 07/05/31(b)			3,390		3,443,559
Hudson Yards Mortgage Trust:
Series 2016-10HY, Class A, 2.84%, 08/10/38(b)			2,640		2,717,284
Series 2019-30HY, Class E, 3.56%, 07/10/39(b)(d)			6,210		6,266,679
IMT Trust:
Series 2017-APTS, Class AFX, 3.48%, 06/15/34(b)			1,540		1,616,124
Series 2017-APTS, Class DFX, 3.61%, 06/15/34(b)(d)			1,600		1,628,552
Series 2017-APTS, Class EFX, 3.61%, 06/15/34(b)(d)			810		809,075
InTown Hotel Portfolio Trust, Series 2018-STAY, Class A, (1 mo. LIBOR US + 0.700%), 2.73%, 01/15/33(a)(b)			620		619,026
JPMBB Commercial Mortgage Securities Trust:
Series 2014-C26, Class A4, 3.49%, 01/15/48			1,247		1,320,768
Series 2015-C33, Class D1, 4.27%, 12/15/48(b)(d)			1,873		1,877,996
JPMDB Commercial Mortgage Securities Trust:
Series 2017-C5, Class A5, 3.69%, 03/15/50			1,880		2,045,799
Series 2017-C5, Class C, 4.51%, 03/15/50(d)			240		258,803

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 65

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
JPMDB Commercial Mortgage Securities Trust: (continued)
Series 2017-C5, Class D, 4.72%, 03/15/50(b)(d)	USD		2,051	$	2,122,433
JPMorgan Chase Commercial Mortgage Securities Corp., Series 2019-BKWD, Class E, (1 mo. LIBOR US + 2.600%), 4.65%, 09/15/29(a)(b)			4,580		4,594,448
JPMorgan Chase Commercial Mortgage Securities Trust:
Series 2012-CBX, Class A4FL, (1 mo. LIBOR US + 1.300%), 3.33%, 06/15/45(a)(b)			419		423,428
Series 2014-C20, Class A5, 3.81%, 07/15/47			1,990		2,125,040
Series 2014-C21, Class A5, 3.78%, 08/15/47			1,420		1,516,551
Series 2014-C22, Class A4, 3.80%, 09/15/47			563		602,383
Series 2015-JP1, Class A5, 3.91%, 01/15/49	.		339		370,264
Series 2015-JP1, Class C, 4.89%, 01/15/49(d)			710		773,857
Series 2015-UES, Class C, 3.62%, 09/05/32(b)(d)			3,431		3,448,556
Series 2015-UES, Class E, 3.74%, 09/05/32(b)(d)			3,880		3,884,062
Series 2015-UES, Class F, 3.62%, 09/05/32(b)(d)			350		349,296
Series 2016-NINE, Class A, 2.95%, 10/06/38(b)(d)			4,650		4,795,036
Series 2017-JP5, Class C, 4.05%, 03/15/50(d)			1,260		1,317,079
Series 2017-JP5, Class D, 4.80%, 03/15/50(b)(d)			1,650		1,736,263
Series 2017-JP6, Class A5, 3.49%, 07/15/50	.		1,180		1,269,698
Series 2017-JP7, Class B, 4.05%, 09/15/50			320		346,062
Series 2019-COR5, Class C, 3.75%, 06/13/52			3,052		3,151,031
Series 2019-MFP, Class E, (1 mo. LIBOR US + 2.100%), 4.13%, 07/15/36(a)(b)			2,460		2,466,147
Series 2019-MFP, Class F, (1 mo. LIBOR US + 3.100%), 5.13%, 07/15/36(a)(b)			891		894,338
Series 2019-OSB, Class E, 3.78%, 06/05/39(b)(d)			1,384		1,434,478
KNDL Mortgage Trust, Series 2019-KNSQ, Class E, (1 mo. LIBOR US + 1.800%), 3.83%, 05/15/36(a)(b)			11,283		11,282,951
Lehman Brothers Small Balance Commercial Mortgage Trust:
Series 2006-2A, Class M2, (1 mo. LIBOR US + 0.390%), 2.54%, 09/25/36(a)(b)			670		654,602
Series 2007-1A, Class 1A, (1 mo. LIBOR US + 0.250%), 2.40%, 03/25/37(a)(b)			1,109		1,077,558
LSTAR Commercial Mortgage Trust, Series 2015-3, Class AS, 3.30%, 04/20/48(b)(d)			1,620		1,655,154
MAD Mortgage Trust:
Series 2017-330M, Class D, 4.11%, 08/15/34(b)(d)			1,085		1,111,603
Series 2017-330M, Class E, 4.17%, 08/15/34(b)(d)			3,010		3,019,586
Morgan Stanley Bank of America Merrill Lynch Trust:
Series 2014-C16, Class A5, 3.89%, 06/15/47			3,880		4,144,854
Series 2015-C23, Class A4, 3.72%, 07/15/50			1,016		1,092,686
Series 2015-C23, Class D, 4.27%, 07/15/50(b)(d)			412		414,288

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Morgan Stanley Bank of America Merrill Lynch Trust: (continued)
Series 2015-C24, Class A4, 3.73%, 05/15/48	USD		840	$	903,205
Series 2015-C25, Class C, 4.68%, 10/15/48(d)			430		465,186
Series 2015-C26, Class A5, 3.53%, 10/15/48			1,144		1,221,294
Series 2015-C26, Class D, 3.06%, 10/15/48(b)			762		724,535
Series 2017-C33, Class C, 4.56%, 05/15/50(d)			840		912,490
Morgan Stanley Capital Barclays Bank Trust, Series 2016-MART, Class A, 2.20%, 09/13/31(b)			820		819,564
Morgan Stanley Capital I Trust:
Series 2006-IQ11, Class C, 6.39%, 10/15/42(d)			1,601		1,640,862
Series 2007-T27, Class AJ, 6.14%, 06/11/42(d)			2,146		2,279,808
Series 2014-CPT, Class E, 3.56%, 07/13/29(b)(d)			250		252,501
Series 2014-CPT, Class F, 3.56%, 07/13/29(b)(d)			2,059		2,071,074
Series 2014-CPT, Class G, 3.56%, 07/13/29(b)(d)			1,290		1,292,916
Series 2015-MS1, Class A4, 3.78%, 05/15/48(d)			420		451,784
Series 2015-MS1, Class C, 4.17%, 05/15/48(d)			1,000		1,040,771
Series 2015-MS1, Class D, 4.17%, 05/05/48(b)(d)			310		299,285
Series 2017-CLS, Class F, (1 mo. LIBOR US + 2.600%), 4.63%, 11/15/34(a)(b)			6,092		6,111,041
Series 2017-H1, Class C, 4.28%, 06/15/50(d)			1,350		1,441,424
Series 2017-H1, Class D, 2.55%, 06/15/50(b)			4,190		3,811,628
Series 2017-HR2, Class D, 2.73%, 12/15/50			430		393,045
Series 2018-H3, Class A5, 4.18%, 07/15/51			175		197,767
Series 2018-H3, Class C, 5.01%, 07/15/51(d)			1,400		1,553,441
Series 2018-MP, Class E, 4.42%, 07/11/40(b)(d)			3,789		3,834,379
Series 2018-SUN, Class F, (1 mo. LIBOR US + 2.550%), 4.58%, 07/15/35(a)(b)			1,015		1,014,992
Series 2019-AGLN, Class D, (1 mo. LIBOR US + 1.750%), 3.78%, 03/15/34(a)(b)			3,605		3,604,994
Series 2019-AGLN, Class F, (1 mo. LIBOR US + 2.600%), 4.63%, 03/15/34(a)(b)			3,840		3,839,991
Series 2019-H6, Class A4, 3.42%, 06/15/52			1,858		1,997,432
Series 2019-L2, Class A4, 4.07%, 03/15/52			1,485		1,675,049
Morgan Stanley Capital I, Inc., Series 2018-H3, Class D, 3.00%, 07/15/51(b)			960		882,400
Natixis Commercial Mortgage Securities Trust:
Series 2018-FL1, Class A, (1 mo. LIBOR US + 0.950%), 3.15%, 06/15/35(a)(b)			757		754,650
Series 2018-FL1, Class MCR1, (1 mo. LIBOR US + 2.350%), 4.55%, 06/15/35(a)(b)			646		646,117
Series 2019-10K, Class D, 4.27%, 05/15/39(b)(d)			4,070		4,349,316
Series 2019-LVL, Class D, 4.44%, 08/15/38(b)(d)			1,550		1,692,329
Olympic Tower Mortgage Trust, Series 2017-OT, Class E, 4.08%, 05/10/39(b)(d)			2,910		2,993,146
One Bryant Park Trust, Series 2019-OBP, Class A, 2.52%, 09/13/49(b)			2,193		2,204,031

66 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
PFP Ltd.:
Series 2019-5, Class A, (1 mo. LIBOR US + 0.970%), 3.00%, 04/14/36(a)(b)	USD		1,533	$	1,534,263
Series 2019-5, Class AS, (1 mo. LIBOR US + 1.420%), 3.45%, 04/14/36(a)(b)			900		901,197
Prima Capital CRE Securitization Ltd.:
Series 2015-4A, Class C, 4.00%, 08/24/49(b)(c)			1,590		1,621,323
Series 2016-6A, Class C, 4.00%, 08/24/40(b)(c)			7,170		7,124,112
RAIT Trust, Series 2017-FL7, Class C, (1 mo. LIBOR US + 2.500%), 4.53%, 06/15/37(a)(b)			550		548,686
Scorpio European Loan Conduit No. 34 DAC, Series 34A, Class C, (3 mo. LIBOR GBP + 2.100%), 2.87%, 05/17/29(a)(b)	GBP		1,185		1,455,624
SG Commercial Mortgage Securities Trust, Series 2019-PREZ, Class D, 3.59%, 09/15/39(b)(d)	USD		2,200		2,238,485
U.S. Mortgage, Series 2018-USDC, Class F, 4.64%, 05/09/38(b)(d)			1,420		1,455,031
UBS Commercial Mortgage Trust, Series 2019-C17, Class A4, 2.92%, 10/15/52			3,795		3,908,842
US, Series 2018-USDC, Class E, 4.64%, 05/13/38(b)(d)			1,160		1,226,065
Velocity Commercial Capital Loan Trust:
Series 2016-1, Class M4, 9.06%, 04/25/46(b)(d)			370		416,836
Series 2016-2, Class M1, 3.66%, 10/25/46(d)			360		367,658
Series 2016-2, Class M2, 4.46%, 10/25/46(d)			200		206,086
Series 2016-2, Class M3, 5.50%, 10/25/46(d)			800		841,450
Series 2016-2, Class M4, 7.23%, 10/25/46(d)			370		397,933
Series 2017-1, Class M2, 4.45%, 05/25/47(b)(d)			410		415,665
Series 2017-1, Class M3, 5.35%, 05/25/47(b)(d)			410		422,801
Series 2017-2, Class M3, 4.24%, 11/25/47(b)(d)			622		631,163
Series 2017-2, Class M4, 5.00%, 11/25/47(b)(d)			373		379,424
Series 2018-1, Class M2, 4.26%, 04/25/48(b)			337		349,014
VNDO Mortgage Trust, Series 2013-PENN, Class D, 4.08%, 12/13/29(b)(d)			550		554,946
Wells Fargo Commercial Mortgage Trust:
Series 2014-LC18, Class A5, 3.41%, 12/15/47			550		579,756
Series 2015-C27, Class C, 3.89%, 02/15/48	.		902		912,462
Series 2015-C28, Class A4, 3.54%, 05/15/48			930		989,890
Series 2015-C30, Class A4, 3.66%, 09/15/48			1,715		1,841,586
Series 2015-C31, Class A4, 3.70%, 11/15/48	.		590		635,423
Series 2015-NXS1, Class A5, 3.15%, 05/15/48			399		416,490
Series 2015-NXS2, Class A5, 3.77%, 07/15/58(d)			3,050		3,287,587
Series 2015-NXS4, Class A4, 3.72%, 12/15/48			608		655,517
Series 2015-NXS4, Class D, 3.75%, 12/15/48(d)			95		96,502
Series 2015-P2, Class A4, 3.81%, 12/15/48			2,150		2,332,790
Series 2015-P2, Class D, 3.24%, 12/15/48(b)			1,784		1,607,910
Series 2017-C39, Class C, 4.12%, 09/15/50	.		590		626,412
Series 2017-C39, Class D, 4.50%, 09/15/50(b)(d)			594		606,154

Security		Par (000)		Value
Commercial Mortgage-Backed Securities (continued)
Wells Fargo Commercial Mortgage Trust: (continued)
Series 2017-C41, Class D, 2.60%, 11/15/50(b)(d)	USD		1,772	$	1,574,638
Series 2017-HSDB, Class A, (1 mo. LIBOR US + 0.850%), 2.89%, 12/13/31(a)(b)			1,508		1,503,570
Series 2018-1745, Class A, 3.87%, 06/15/36(b)(d)			930		1,022,612
Series 2018-BXI, Class E, (1 mo. LIBOR US + 2.157%), 4.18%, 12/15/36(a)(b)			877		881,517
Series 2018-C44, Class D, 3.00%, 05/15/51(b)			1,100		1,034,571
Series 2018-C45, Class C, 4.73%, 06/15/51	.		530		575,797
WFRBS Commercial Mortgage Trust:
Series 2011-C3, Class A3FL, (1 mo. LIBOR US + 0.950%), 2.98%, 03/15/44(a)(b)			38		38,403
Series 2014-C21, Class A5, 3.68%, 08/15/47 .			1,515		1,610,003
Series 2014-C24, Class B, 4.20%, 11/15/47(d)			770		802,498
Total Commercial Mortgage-Backed Securities — 3.2% (Cost: $491,757,014)					507,878,138
Interest Only Collateralized Mortgage Obligations — 0.0%
Seasoned Credit Risk Transfer Trust, Series 2017-3, Class BIO, 1.22%, 07/25/56(b)(d)			3,267		406,228
Voyager OPTONE Delaware Trust, Series 2009-1, Class SAA7, 2.36%, 02/25/38(b)(d)			14,563		5,327,244
Total Interest Only Collateralized Mortgage Obligations — 0.0% (Cost: $5,964,438)					5,733,472
Interest Only Commercial Mortgage-Backed Securities — 0.3%
245 Park Avenue Trust, Series 2017-245P, Class XA, 0.15%, 06/05/37(b)(d)			13,000		175,630
Banc of America Commercial Mortgage Trust:
Series 2017-BNK3, Class XB, 0.78%, 02/15/50(d)			11,850		510,082
Series 2017-BNK3, Class XD, 1.44%, 02/15/50(b)(d)			5,000		408,850
BANK:
Series 2019-BN20, Class XA, 0.84%, 09/15/61(d)			11,565		800,814
Series 2019-BN20, Class XB, 0.36%, 09/15/61(d)			39,279		1,324,068
Barclays Commercial Mortgage Trust:
Series 2015-SRCH, Class XA, 1.12%, 08/10/35(b)(d)			17,710		1,054,985
Series 2019-C3, Class XA, 1.51%, 05/15/52(d)			19,823		2,090,265
Benchmark Mortgage Trust:
Series 2019-B13, Class XA, 1.27%, 08/15/57(d)			68,774		5,922,452
Series 2019-B9, Class XA, 1.21%, 03/15/52(d)			21,009		1,713,247
CFCRE Commercial Mortgage Trust:
Series 2016-C3, Class XD, 1.86%, 01/10/48(b)(d)			5,497		517,927
Series 2016-C4, Class XB, 0.89%, 05/10/58(d)			5,810		259,765

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 67

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Interest Only Commercial Mortgage-Backed Securities (continued)
Commercial Mortgage Pass-Through Certificates:
Series 2013-CR6, Class XA, 1.19%, 03/10/46(d)	USD		19,912	$	522,190
Series 2015-3BP, Class XA, 0.17%, 02/10/35(b)(d)			150,000		766,500
Series 2015-CR25, Class XA, 1.05%, 08/10/48(d)			5,149		213,356
Series 2018-COR3, Class XD, 1.75%, 05/10/51(b)(d)			3,200		404,657
Core Industrial Trust:
Series 2015-TEXW, Class XA, 0.90%, 02/10/34(b)(d)			12,812		190,091
Series 2015-WEST, Class XA, 1.08%, 02/10/37(b)(d)			9,716		440,510
CSAIL Commercial Mortgage Trust:
Series 2017-CX10, Class XB, 0.22%, 11/15/50(d)			12,490		206,918
Series 2019-C16, Class XA, 1.73%, 06/15/52(d)			50,881		6,239,894
Series 2019-C17, Class XA, 1.37%, 09/15/52(d)			48,290		5,083,203
Series 2019-C17, Class XB, 0.56%, 09/15/52(d)			19,090		951,176
DBGS Mortgage Trust, Series 2019-1735, Class X, 0.43%, 04/10/37(b)(d)			21,535		595,012
Deutsche Bank JPMorgan Mortgage Trust, Series 2017-C6, Class XD, 1.00%, 06/10/50(b)(d)			5,780		350,904
FREMF Mortgage Trust, Series 2015-K718, Class X2A, 0.10%, 02/25/48(b)(d)			86,509		154,618
GS Mortgage Securities Corp. II, Series 2005-ROCK, Class X1, 0.21%, 05/03/32(b)(d)			21,000		300,105
JPMBB Commercial Mortgage Securities Trust:
Series 2014-C22, Class XA, 1.01%, 09/15/47(d)			2,083		71,496
Series 2014-C23, Class XA, 0.81%, 09/15/47(d)			31,558		779,793
Series 2015-C29, Class XA, 0.90%, 05/15/48(d)			2,628		65,844
JPMDB Commercial Mortgage Securities Trust, Series 2016-C4, Class XC, 0.75%, 12/15/49(b)(d)			4,940		228,627
JPMorgan Chase Commercial Mortgage Securities Trust:
Series 2013-LC11, Class XB, 0.65%, 04/15/46(d)			4,570		83,100
Series 2016-JP3, Class XC, 0.75%, 08/15/49(b)(d)			13,040		581,714
LSTAR Commercial Mortgage Trust, Series 2017-5, Class X, 1.26%, 03/10/50(b)(d)			3,500		145,403
Morgan Stanley Bank of America Merrill Lynch Trust:
Series 2014-C19, Class XF, 1.35%, 12/15/47(b)(d)			4,370		215,616
Series 2015-C26, Class XD, 1.49%, 10/15/48(b)(d)			4,490		328,668
Series 2016-C31, Class XA, 1.56%, 11/15/49(d)			2,576		189,366

Security		Par (000)		Value
Interest Only Commercial Mortgage-Backed Securities (continued)
Morgan Stanley Capital I Trust:
Series 2016-UBS9, Class XD, 1.69%, 03/15/49(b)(d)	USD		13,984	$	1,264,993
Series 2017-H1, Class XD, 2.36%, 06/15/50(b)(d)			3,293		478,111
Series 2018-H4, Class XA, 1.04%, 12/15/51(d)			13,951		912,242
Series 2019-H6, Class XB, 0.87%, 06/15/52(d)			23,510		1,479,061
Series 2019-L2, Class XA, 1.20%, 03/15/52(d)			8,861		723,502
Olympic Tower Mortgage Trust, Series 2017-OT, Class XA, 0.51%, 05/10/39(b)(d)			36,697		1,037,424
One Market Plaza Trust:
Series 2017-1MKT, Class XCP, 0.22%, 02/10/32(b)(d)			53,230		183,111
Series 2017-1MKT, Class XNCP, 0.00%, 02/10/32(b)(c)(d)			10,646		106
UBS Commercial Mortgage Trust:
Series 2018-C14, Class XA, 1.18%, 12/15/51(d)			4,977		370,840
Series 2019-C17, Class XA, 1.64%, 10/15/52(d)			32,837		3,797,205
Wells Fargo Commercial Mortgage Trust:
Series 2015-NXS1, Class XB, 0.49%, 05/15/48(d)			3,210		88,051
Series 2015-NXS4, Class XA, 1.05%, 12/15/48(d)			3,162		137,506
Series 2016-BNK1, Class XD, 1.40%, 08/15/49(b)(d)			4,420		316,074
Series 2018-C44, Class XA, 0.92%, 05/15/51(d)			25,867		1,355,024
Series 2019-C50, Class XA, 1.63%, 05/15/52(d)			21,542		2,322,094
Total Interest Only Commercial Mortgage-Backed Securities — 0.3% (Cost: $48,172,777)					48,352,190
Principal Only Collateralized Mortgage Obligations — 0.0%
Seasoned Credit Risk Transfer Trust, Series 2017-3, Class B, 0.00%, 07/25/56(b)(h)			1,602		133,756
Total Principal Only Collateralized Mortgage Obligations — 0.0% (Cost: $150,310)					133,756
Total Non-Agency Mortgage-Backed Securities — 5.2% (Cost: $809,772,570)					820,401,401
Preferred Securities — 0.8%
Capital Trusts — 0.8%
Banks — 0.4%
Banco Mercantil del Norte SA:
(5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 5.035%), 6.88%(b)(j)(k)			903		909,772
(10 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 5.353%), 7.63%(b)(j)(k)			903		919,649

68 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Banks (continued)
Bank of America Corp., (3 mo. LIBOR US + 2.931%), 5.88%(j)(k)	USD		7,350	$	7,938,000
Bank of East Asia Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 4.257%), 5.88%(j)(k)			735		750,802
BNP Paribas SA:
(5 yr. Swap Semi 30/360 US + 5.150%), 7.38%(b)(j)(k)			7,450		8,325,375
(5 yr. Swap Semi 30/360 US + 6.314%), 7.63%(b)(j)(k)			5,920		6,238,200
Burgan Bank SAK, (5 yr. Swap Semi 30/360 US + 4.007%), 5.75%(j)(k)			350		348,513
Credit Agricole SA, (5 yr. Swap Semi 30/360 US + 6.185%), 8.13%(b)(j)(k)			10,300		12,115,375
Emirates NBD PJSC, (6 yr. Swap Semi 30/360 US + 3.656%), 6.13%(j)(k)			1,650		1,728,375
HSBC Holdings PLC:
(USD Swap Rate 11:00 am NY 1 + 3.746%), 6.00%(j)(k)			6,905		7,101,931
(USD Swap Rate 11:00 am NY 1 + 3.606%), 6.50%(j)(k)			2,860		2,991,417
Itau Unibanco Holding SA:
(5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 3.981%), 6.13%(b)(j)(k)			1,607		1,621,513
(5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 3.863%), 6.50%(b)(j)(k)			946		971,560
JPMorgan Chase & Co., (Secured Overnight Financing Rate + 3.380%), 5.00%(j)(k)			10,890		11,133,609
Kookmin Bank, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 2.639%), 4.35%(j)(k)			1,700		1,740,375
Lehman Brothers Holdings Capital Trust VII, 5.86%(c)(f)(i)(k)			1,888		—
Shinhan Financial Group Co. Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 3.051%), 5.88%(j)(k)			900		967,219
United Overseas Bank Ltd., (5 yr. Swap Semi 30/360 US + 1.794%), 3.88%(j)(k)			864		868,590
					66,670,275
Capital Markets — 0.2%
Bank of New York Mellon Corp.:
Series F, (3 mo. LIBOR US + 3.131%), 4.63%(j)(k)			7,622		7,789,379
(3 mo. LIBOR US + 3.420%), 4.95%(j)(k)			4,380		4,401,900
State Street Corp.:
(3 mo. LIBOR US + 3.597%), 5.25%(j)(k)			4,015		4,085,263
(3 mo. LIBOR US + 2.539%), 5.63%(j)(k)			9,655		9,990,318
UBS Group Funding Switzerland AG, (5 yr. Swap Semi 30/360 US + 4.344%), 7.00%(b)(j)(k)			11,250		11,947,500
					38,214,360
Commercial Services & Supplies — 0.0%
King Talent Management Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 3.521%), 5.60%(j)(k)			600		522,937
Construction & Engineering — 0.0%
Chalieco Hong Kong Corp. Ltd., (3 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 8.292%), 5.70%(j)(k)			200		200,937
Consumer Finance — 0.0%
Credito Real SAB de CV SOFOM ER, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 7.026%), 9.13%(b)(j)(k)			480		493,350

Security		Par (000)		Value
Insurance — 0.0%
Heungkuk Life Insurance Co. Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 2.472%), 4.48%(j)(k)	USD		1,000	$	972,500
KDB Life Insurance Co. Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 4.658%), 7.50%(j)(k)			900		890,156
Mitsui Sumitomo Insurance Co. Ltd., (5 yr. Swap Semi 30/360 US + 3.256%), 4.95%(j)(k)			2,000		2,215,000
					4,077,656
Machinery — 0.0%
Weichai International Hong Kong Energy Group Co. Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 6.084%), 3.75%(j)(k)			278		277,305
Media — 0.1%
NBCUniversal Enterprise, Inc., 5.25%(b)(k)			13,680		14,090,400
Oil, Gas & Consumable Fuels — 0.1%
Enbridge, Inc., (3 mo. LIBOR US + 3.418%), 5.50%, 07/15/77(j)			10,120		10,185,487
Real Estate Management & Development — 0.0%
Agile Group Holdings Ltd., (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 9.216%), 6.88%(j)(k)			200		194,688
Transportation Infrastructure — 0.0%
Royal Capital BV, (5 yr. U.S. Treasury Yield Curve Rate T Note Constant Maturity + 5.930%), 4.88%(j)(k)			219		220,275
Total Preferred Securities — 0.8% (Cost: $130,671,485)					135,147,670
Taxable Municipal Bonds — 4.8%
Arizona — 0.0%
Arizona Health Facilities Authority RB, 2.22%, 01/01/37(d)			1,355		1,323,195
Salt River Project Agricultural Improvement & Power District RB, 5.00%, 12/01/45			5,310		6,171,070
					7,494,265
California — 1.2%
Bay Area Toll Authority RB:
2.43%, 04/01/26			7,195		7,236,731
6.92%, 04/01/40			3,145		4,689,069
7.04%, 04/01/50			17,715		29,708,764
California Health Facilities Financing Authority RB:
5.00%, 08/15/33			1,190		1,457,667
5.00%, 08/15/47			1,650		1,926,259
California Pollution Control Financing Authority RB, 5.00%, 11/21/45(b)			1,000		1,065,660
City of Riverside, CA Electric Revenue RB, 7.61%, 10/01/40			1,325		2,128,334
Contra Costa Community College District GO, 6.50%, 08/01/34			570		771,501
Los Angeles Community College District GO, 6.60%, 08/01/42			5,160		8,072,407
Los Angeles Department of Water & Power RB, 6.60%, 07/01/50			2,645		4,332,325
Los Angeles Unified School District GO: 5.75%, 07/01/34			415		539,670

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 69

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
California (continued)
Los Angeles Unified School District GO: (continued)
6.76%, 07/01/34	USD		7,405	$	10,407,283
Orange County Local Transportation Authority RB, 6.91%, 02/15/41			2,790		4,071,698
Regents of the University of California Medical Center Pooled Revenue RB:
5.00%, 05/15/47			1,500		1,744,470
6.58%, 05/15/49			2,860		4,273,984
Sacramento County Sanitation Districts Financing Authority RB, 1.96%, 12/01/35(d)			8,500		8,093,122
San Diego Public Facilities Financing Authority Sewer Revenue RB, 5.00%, 05/15/39			1,250		1,520,900
San Francisco City & County Airport Comm-San Francisco International Airport RB:
5.00%, 05/01/46			3,330		3,891,571
5.00%, 05/01/50			2,695		3,312,640
San Jose Redevelopment Agency Successor Agency TA:
2.96%, 08/01/24			7,265		7,584,660
3.18%, 08/01/26			2,025		2,152,636
3.13%, 08/01/28			4,275		4,511,493
3.25%, 08/01/29			3,585		3,797,447
State of California GO:
5.00%, 10/01/25			3,685		4,474,069
2.65%, 04/01/26			10,385		10,668,303
7.50%, 04/01/34			2,210		3,387,753
4.60%, 04/01/38			16,540		18,739,655
7.55%, 04/01/39			3,715		6,119,794
7.30%, 10/01/39			2,575		4,012,133
7.35%, 11/01/39			720		1,132,531
University of California RB:
3.06%, 07/01/25			1,865		1,958,642
3.35%, 07/01/29			6,210		6,718,289
4.60%, 05/15/31			3,755		4,366,239
5.00%, 05/15/32			2,070		2,482,655
5.77%, 05/15/43			3,980		5,403,885
4.86%, 05/15/2112			1,415		1,872,795
					188,627,034
Colorado — 0.1%
City of Aurora, CO Water Revenue RB:
5.00%, 08/01/41			3,500		4,215,820
5.00%, 08/01/46			3,530		4,180,402
Colorado Health Facilities Authority RB:
5.25%, 02/01/31			785		825,184
5.00%, 08/01/44			9,250		10,994,827
					20,216,233
Connecticut — 0.2%
Connecticut State Health & Educational Facility Authority RB, 5.00%, 07/01/45			1,700		1,927,596
State of Connecticut GO:
2.99%, 01/15/23			3,680		3,770,896
3.31%, 01/15/26			4,655		4,900,086
5.09%, 10/01/30			7,910		9,297,414
5.85%, 03/15/32			10,760		14,137,134
					34,033,126
District of Columbia — 0.1%
District of Columbia RB:
5.00%, 07/15/34			775		913,407
5.00%, 07/15/35			775		912,462
Metropolitan Washington Airports Authority Dulles Toll Road Revenue RB:
7.46%, 10/01/46			1,060		1,754,597
5.00%, 10/01/53			1,000		1,071,640

Security		Par (000)		Value
District of Columbia (continued)
Metropolitan Washington Airports Authority RB, 5.00%, 10/01/32	USD		2,710	$	3,243,301
					7,895,407
Florida — 0.2%
Canaveral Port Authority RB:
5.00%, 06/01/45			1,890		2,234,471
5.00%, 06/01/48			1,890		2,272,252
County of Miami-Dade, FL Aviation RB, 4.06%, 10/01/31			1,765		1,967,940
County of Miami-Dade, FL Aviation Revenue RB:
3.35%, 10/01/29			560		591,338
2.53%, 10/01/30			5,705		5,641,960
3.45%, 10/01/30			1,030		1,092,531
3.50%, 10/01/31			965		1,024,126
5.00%, 10/01/38			1,600		1,848,800
5.00%, 10/01/40			1,650		1,963,500
Putnam County Development Authority RB, 5.00%, 03/15/42			2,965		3,593,224
Sumter Landing Community Development District RB, 4.17%, 10/01/47			920		1,067,853
					23,297,995
Georgia — 0.1%
City of Atlanta, GA Water & Wastewater Revenue RB, 5.00%, 11/01/40			885		1,034,264
Metropolitan Atlanta Rapid Transit Authority RB:
4.00%, 07/01/25			1,425		1,632,281
5.00%, 07/01/41			2,220		2,613,584
Municipal Electric Authority of Georgia RB:
6.64%, 04/01/57			1,601		2,198,141
6.66%, 04/01/57			1,895		2,717,165
					10,195,435
Idaho — 0.0%
Idaho Health Facilities Authority RB, 5.00%, 12/01/47			1,155		1,385,238
Illinois — 0.1%
State of Illinois GO, 5.10%, 06/01/33			13,140		14,211,041
Indiana — 0.0%
Indiana Finance Authority RB, 5.00%, 10/01/45			3,120		3,547,502
Indiana Housing & Community Development Authority RB GNMA Collateral, 3.80%, 07/01/38			930		993,221
					4,540,723
Kentucky — 0.0%
Kentucky Economic Development Finance Authority RB, 5.25%, 06/01/50			850		959,803
Louisiana — 0.0%
Louisiana Public Facilities Authority RB, 5.00%, 07/01/48			1,240		1,473,864
New Orleans Aviation Board RB, 5.00%, 01/01/40			1,140		1,284,746
					2,758,610
Maryland — 0.0%
Maryland Community Development Administration RB, 3.85%, 09/01/33			1,620		1,778,452
Maryland Health & Higher Educational Facilities Authority RB, 5.25%, 07/01/27			815		940,404
State of Maryland GO, 5.00%, 08/01/30			3,100		4,082,607
					6,801,463

70 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Massachusetts — 0.1%
Commonwealth of Massachusetts GO, 2.90%, 09/01/49	USD		4,350	$	4,243,338
Massachusetts Development Finance Agency RB:
5.00%, 07/01/43			2,390		2,863,483
5.00%, 07/01/47			1,260		1,501,315
5.00%, 07/01/48			2,535		3,014,850
Massachusetts Educational Financing Authority RB, 5.00%, 01/01/22			500		537,030
Massachusetts Housing Finance Agency RB:
4.50%, 12/01/39			940		981,125
4.60%, 12/01/44			995		1,066,282
4.50%, 12/01/48			1,160		1,224,102
Massachusetts Port Authority RB, 5.00%, 07/01/43			1,590		1,859,298
Massachusetts Water Resources Authority RB, 5.00%, 08/01/40			920		1,109,069
					18,399,892
Michigan — 0.1%
Great Lakes Water Authority Water Supply System Revenue RB, 5.25%, 07/01/33			755		911,889
Michigan Finance Authority RB:
5.00%, 06/01/39			840		950,636
5.00%, 11/15/41			850		1,003,816
5.00%, 12/01/47			5,290		5,780,859
2.86%, 09/01/49(d)			6,090		6,197,671
Michigan State Housing Development Authority RB:
3.55%, 10/01/33			1,055		1,132,479
4.00%, 10/01/43			1,010		1,094,901
4.05%, 10/01/48			465		500,247
4.15%, 10/01/53			2,400		2,589,096
Royal Oak Hospital Finance Authority RB, 5.00%, 09/01/39			1,160		1,301,961
					21,463,555
Mississippi — 0.0%
Mississippi Hospital Equipment & Facilities Authority RB, 5.00%, 09/01/46			1,610		1,802,942
Montana — 0.1%
Health & Educational Facilities Authority of the State of Missouri RB:
5.00%, 11/15/29			840		1,004,380
3.65%, 01/15/46			605		667,424
3.09%, 09/15/51			3,585		3,544,418
Kansas City Industrial Development Authority RB AGM, 5.00%, 03/01/49			4,700		5,640,799
					10,857,021
Nebraska — 0.0%
Public Power Generation Agency RB, 5.00%, 01/01/35			1,070		1,259,572
New Jersey — 0.1%
New Jersey State Turnpike Authority RB, 7.41%, 01/01/40			2,329		3,732,386
New Jersey Transportation Trust Fund Authority RB:
5.75%, 12/15/28			3,350		3,877,357
5.00%, 06/15/29			915		1,072,151
					8,681,894
New York — 1.0%
City of New York, NY GO:
3.76%, 12/01/27			2,675		2,959,299
2.85%, 08/01/31			5,380		5,515,737

Security		Par (000)		Value
New York (continued)
City of New York, NY GO: (continued)
2.90%, 08/01/32	USD		9,025	$	9,329,413
6.27%, 12/01/37			4,215		6,079,210
Dutchess County Local Development Corp. RB, 5.00%, 07/01/46			2,685		3,131,328
Metropolitan Transportation Authority RB:
5.87%, 11/15/39			735		970,362
6.67%, 11/15/39			350		513,247
5.00%, 11/15/40			3,000		3,716,550
6.69%, 11/15/40			1,160		1,679,529
6.81%, 11/15/40			860		1,251,807
5.00%, 11/15/41			1,860		2,328,999
5.00%, 11/15/42			3,590		4,427,691
5.00%, 11/15/43			2,530		3,160,577
5.00%, 11/15/52			3,410		4,127,464
New York City Housing Development Corp. RB:
3.70%, 11/01/38			1,090		1,150,615
3.85%, 11/01/43			3,300		3,423,981
4.00%, 11/01/53			2,510		2,641,875
New York City Transitional Finance Authority Building Aid Revenue RB, 5.00%, 07/15/40			930		1,087,682
New York City Transitional Finance Authority Future Tax Secured Revenue RB:
3.65%, 11/01/24			4,050		4,292,555
3.55%, 05/01/25			5,040		5,399,503
3.75%, 11/01/25			4,050		4,298,873
3.05%, 05/01/27			4,675		4,903,701
3.35%, 11/01/30			6,190		6,606,030
3.90%, 08/01/31			4,860		5,364,322
New York City Water & Sewer System RB:
5.75%, 06/15/41			1,330		1,915,213
6.01%, 06/15/42			665		978,567
5.38%, 06/15/43			2,920		3,063,168
5.38%, 06/15/43			1,490		1,557,601
5.44%, 06/15/43			1,775		2,487,432
5.50%, 06/15/43			5,285		5,552,474
5.88%, 06/15/44			1,240		1,845,170
New York Convention Center Development Corp. RB:
5.00%, 11/15/40			930		1,112,531
5.00%, 11/15/46			2,370		2,873,767
New York Liberty Development Corp. RB, 5.00%, 11/15/44(b)			2,200		2,426,292
New York State Dormitory Authority RB, 5.39%, 03/15/40			1,470		1,954,336
New York State Urban Development Corp. RB:
3.12%, 03/15/25			1,955		2,058,517
3.25%, 03/15/25			2,325		2,465,895
3.32%, 03/15/29			4,035		4,279,642
New York Transportation Development Corp. RB:
5.00%, 08/01/20			2,200		2,250,050
5.00%, 07/01/46			730		804,241
5.25%, 01/01/50			9,190		10,268,998
Port Authority of New York & New Jersey RB:
5.65%, 11/01/40			2,165		2,963,842
4.96%, 08/01/46			3,735		4,929,677
4.93%, 10/01/51			1,045		1,420,740
4.46%, 10/01/62			3,155		4,026,379
TSASC, Inc. RB, 5.00%, 06/01/41			1,700		1,898,951
					151,493,833
North Carolina — 0.0%
North Carolina Turnpike Authority RB, AGM, 5.00%, 01/01/35			1,290		1,591,989

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 71

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Ohio — 0.2%
American Municipal Power, Inc. RB:
7.83%, 02/15/41	USD		1,500	$	2,392,050
6.45%, 02/15/44			4,635		6,690,715
Buckeye Tobacco Settlement Financing Authority RB, 5.88%, 06/01/47			5,210		5,216,565
JobsOhio Beverage System RB, 3.99%, 01/01/29			8,385		9,214,444
					23,513,774
Oklahoma — 0.0%
Oklahoma Development Finance Authority RB:
5.25%, 08/15/43			1,000		1,188,460
5.50%, 08/15/57			4,760		5,670,255
					6,858,715
Oregon — 0.2%
Oregon School Boards Association GO:
AMBAC, 4.76%, 06/30/28			5,785		6,545,612
5.55%, 06/30/28			7,175		8,496,635
5.68%, 06/30/28			10,105		12,222,705
State of Oregon GO, 5.89%, 06/01/27			8,145		9,879,233
					37,144,185
Pennsylvania — 0.2%
Berks County Industrial Development Authority RB, 5.00%, 11/01/47			1,780		2,052,393
City of Philadelphia, PA Airport Revenue RB, 5.00%, 07/01/42			1,000		1,192,050
Commonwealth Financing Authority RB:
3.86%, 06/01/38			2,325		2,556,431
4.14%, 06/01/38			1,730		1,973,653
3.81%, 06/01/41			11,155		12,342,115
DuBois Hospital Authority RB, 5.00%, 07/15/43			1,290		1,527,863
Pennsylvania Economic Development Financing Authority RB:
5.00%, 12/31/22			1,000		1,090,900
5.00%, 12/31/38			320		365,456
Pennsylvania Turnpike Commission RB:
5.00%, 12/01/43			3,460		4,185,770
5.00%, 12/01/46			1,120		1,314,354
5.25%, 06/01/47			2,370		2,801,198
5.00%, 12/01/48			2,805		3,379,941
					34,782,124
Puerto Rico — 0.0%
Commonwealth of Puerto Rico GO, 8.00%, 07/01/35(f)(i)			6,430		3,860,585
South Carolina — 0.1%
Lexington County Health Services District, Inc. RB, 5.00%, 11/01/41			960		1,110,413
South Carolina Public Service Authority RB, 2.39%, 12/01/23			7,497		7,667,857
Spartanburg County School District No. 7 GO, SCSDE, 5.00%, 03/01/48			645		785,720
					9,563,990
Tennessee — 0.0%
Metropolitan Government Nashville & Davidson County Health & Educational Facilities Board RB:
5.00%, 07/01/40			930		1,084,603
5.00%, 07/01/46			1,800		2,090,718
Tennessee Housing Development Agency RB:
3.75%, 07/01/38			975		1,040,725
3.85%, 07/01/43			460		486,027

Security		Par (000)		Value
Tennessee (continued)
Tennessee Housing Development Agency RB: (continued)
3.95%, 01/01/49	USD		360	$	383,656
					5,085,729
Texas — 0.3%
Aldine Independent School District GO PSF, 5.00%, 02/15/43			1,020		1,252,968
Central Texas Regional Mobility Authority RB:
5.00%, 01/01/45			900		1,024,677
5.00%, 01/01/46			900		1,031,751
City of Austin, TX Water & Wastewater System Revenue RB, 5.00%, 11/15/43			1,650		1,880,653
City Public Service Board of San Antonio, TX RB, 5.81%, 02/01/41			3,260		4,687,163
Dallas Area Rapid Transit RB:
5.00%, 12/01/41			1,780		2,108,303
5.00%, 12/01/46			2,410		2,841,631
Dallas/Fort Worth International Airport RB:
5.00%, 11/01/42			2,025		2,146,217
Series A, 5.00%, 11/01/43			60		62,218
3.14%, 11/01/45			2,420		2,443,208
5.00%, 11/01/45			3,670		3,807,111
5.00%, 11/01/45			2,650		2,804,389
New Hope Cultural Education Facilities Finance Corp. RB, 5.00%, 08/15/47			1,380		1,640,378
North Texas Tollway Authority RB:
5.00%, 01/01/29			3,500		4,461,520
5.00%, 01/01/43			1,245		1,502,665
San Antonio Water System RB, 5.00%, 05/15/39			1,520		1,775,284
Texas A&M University RB, 2.84%, 05/15/27			2,240		2,328,838
Texas Municipal Gas Acquisition & Supply Corp. RB, 6.25%, 12/15/26			790		919,726
Texas Private Activity Bond Surface Transportation Corp. RB:
5.00%, 12/31/55			370		412,125
5.00%, 06/30/58			7,185		8,395,816
					47,526,641
Utah — 0.0%
Salt Lake City Corp. Airport Revenue RB:
5.00%, 07/01/47			2,960		3,474,330
5.00%, 07/01/47			1,100		1,313,961
					4,788,291
Virginia — 0.1%
Chesapeake Bay Bridge & Tunnel District RB:
AGM, 5.00%, 07/01/41			880		1,037,080
5.00%, 07/01/51			700		803,950
Tobacco Settlement Financing Corp. RB, 6.71%, 06/01/46			4,135		3,975,265
Virginia Small Business Financing Authority RB:
5.00%, 12/31/52			2,535		2,924,046
5.00%, 12/31/56			2,190		2,519,420
					11,259,761
Washington — 0.1%
Central Puget Sound Regional Transit Authority RB, 5.00%, 11/01/50			1,730		2,028,529
Grant County Public Utility District No. 2 RB, 4.58%, 01/01/40			600		706,566
Port of Seattle, WA RB, 5.00%, 05/01/43			930		1,089,551
State of Washington GO: 5.00%, 08/01/40			2,720		3,201,086

72 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)			Value
Washington (continued)
State of Washington GO: (continued)
5.00%, 08/01/40	USD		1,120		$	1,366,781
5.00%, 02/01/41			1,880			2,269,818
5.00%, 08/01/41			1,175			1,432,619
						12,094,950
West Virginia — 0.1%
Tobacco Settlement Finance Authority RB, 7.47%, 06/01/47			6,535			6,749,283
West Virginia Hospital Finance Authority RB:
5.00%, 06/01/20			965			987,108
5.00%, 06/01/21			960			1,014,355
5.00%, 06/01/22			1,050			1,143,713
5.00%, 06/01/23			870			975,000
5.00%, 06/01/24			935			1,076,101
						11,945,560
Wisconsin — 0.1%
Public Finance Authority RB, 5.00%, 09/30/49			5,440			5,536,778
State of Wisconsin GO:
5.00%, 05/01/36			1,520			1,792,065
5.00%, 05/01/38			1,530			1,796,557
State of Wisconsin RB, 3.15%, 05/01/27			1,900			2,016,603
						11,142,003
Total Taxable Municipal Bonds — 4.8% (Cost: $712,771,630)						757,533,379
U.S. Government Sponsored Agency Securities — 79.3%
Agency Obligations — 0.0%
Fannie Mae 6.63%, 11/15/30			1,450			2,123,474
Collateralized Mortgage Obligations — 0.0%
Fannie Mae:
Series 2003-W5, Class A, (1 mo. LIBOR US + 0.110%), 2.37%, 04/25/33(a)			2			1,895
Series 2005-48, Class AR, 5.50%, 02/25/35			—	(r)		218
Freddie Mac:
Series 2015-DN1, Class B, (1 mo. LIBOR US + 11.500%), 13.52%, 01/25/25(a)			494			660,683
Series 2015-HQ2, Class B, (1 mo. LIBOR US + 7.950%), 9.97%, 05/25/25(a)			524			623,747
Series 2017-DNA2, Class B1, (1 mo. LIBOR US + 5.150%), 7.17%, 10/25/29(a)			590			680,130
Series 2017-DNA3, Class B1, (1 mo. LIBOR US + 4.450%), 6.47%, 03/25/30(a)			1,860			2,052,515
Series 2017-HRP1, Class M2, (1 mo. LIBOR US + 2.450%), 4.47%, 12/25/42(a)			734			741,948
						4,761,136
Commercial Mortgage-Backed Securities — 0.1%
Fannie MaeSeries 2006-M2, Class A2A, 5.27%, 10/25/32(d)			1,564			1,779,780
Freddie Mac:
Series K076, Class A2, 3.90%, 06/25/51			5,896			6,650,145
Series KL4F, Class A2AS, 3.68%, 10/25/25(d)			1,664			1,784,745
Series KW06, Class A2, 3.80%, 06/25/28(d)			1,040			1,167,353
Ginnie Mae:
Series 2015-97, Class VA, 2.25%, 12/16/38			1,065			1,052,299
Series 2016-158, Class VA, 2.00%, 03/16/35			696			672,656
						13,106,978

Security		Par (000)		Value
Interest Only Commercial Mortgage-Backed Securities — 0.2%
Fannie Mae:
Series 2013-M5, Class X2, 2.16%, 01/25/22(d)	USD		4,950	$	113,346
Series 2015-M4, Class X2, 0.48%, 07/25/22(d)			30,362		237,330
Freddie Mac:
Series K718, Class X1, 0.73%, 01/25/22(d)			5,529		66,320
Series KW03, Class X1, 0.98%, 06/25/27(d)			7,657		383,589
Ginnie Mae:
Series 2012-23, Class IO, 0.56%, 06/16/53(d)			3,454		79,708
Series 2013-191, Class IO, 0.73%, 11/16/53(d)			2,834		90,848
Series 2013-30, Class IO, 0.80%, 09/16/53(d)			12,748		496,221
Series 2013-63, Class IO, 0.79%, 09/16/51(d)			17,008		862,587
Series 2013-78, Class IO, 0.76%, 10/16/54(d)			13,472		533,914
Series 2014-40, Class AI, 1.00%, 02/16/39			1,568		7,645
Series 2014-52, Class AI, 0.83%, 08/16/41			4,244		88,190
Series 2015-173, Class IO, 0.88%, 09/16/55(d)			6,417		397,247
Series 2015-22, Class IO, 0.70%, 03/16/55(d)			9,625		418,281
Series 2015-37, Class IO, 0.76%, 10/16/56(d)			2,376		131,215
Series 2015-48, Class IO, 0.69%, 02/16/50(d)			5,451		234,817
Series 2016-110, Class IO, 1.03%, 05/16/58(d)			6,374		473,949
Series 2016-113, Class IO, 1.18%, 02/16/58(d)			8,322		748,119
Series 2016-119, Class IO, 1.12%, 04/16/58(d)			2,688		195,442
Series 2016-125, Class IO, 1.04%, 12/16/57(d)			8,520		645,056
Series 2016-128, Class IO, 0.95%, 09/16/56(d)			13,341		977,099
Series 2016-13, Class IO, 0.87%, 04/16/57(d)			13,336		814,017
Series 2016-152, Class IO, 0.92%, 08/15/58(d)			8,576		617,196
Series 2016-162, Class IO, 1.00%, 09/16/58(d)			25,858		2,045,643
Series 2016-165, Class IO, 0.97%, 12/16/57(d)			6,554		510,682
Series 2016-175, Class IO, 0.92%, 09/16/58(d)			11,304		807,608
Series 2016-26, Class IO, 0.96%, 02/16/58(d)			33,182		2,284,524
Series 2016-36, Class IO, 0.94%, 08/16/57(d)			4,419		312,368
Series 2016-67, Class IO, 1.17%, 07/16/57(d)			5,120		395,322
Series 2016-87, Class IO, 1.00%, 08/16/58(d)			25,814		1,738,875
Series 2016-92, Class IO, 1.00%, 04/16/58(d)			8,455		594,810
Series 2016-96, Class IO, 0.98%, 12/16/57(d)			16,794		1,221,450
Series 2016-97, Class IO, 1.04%, 07/16/56(d)			9,833		725,392

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 73

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Interest Only Commercial Mortgage-Backed Securities (continued)
Ginnie Mae: (continued)
Series 2018-106, Class IO, 0.49%, 04/16/60(d)	USD		11,140	$	632,767
Series 2018-85, Class IO, 0.52%, 07/16/60(d)			11,420		649,642
					20,531,219
Mortgage-Backed Securities — 79.0%
Fannie Mae Mortgage-Backed Securities:
4.50%, 02/01/25 - 10/01/49(s)			882,821		941,545,662
2.50%, 09/01/27 - 10/01/49(s)			216,760		218,114,706
3.00%, 04/01/28 - 10/01/49(s)			1,421,802		1,449,826,499
3.50%, 08/01/28 - 10/01/49(s)			2,332,311		2,402,392,388
4.00%, 08/01/31 - 10/01/49(s)			3,079,123		3,215,826,729
2.00%, 10/01/31 - 03/01/32			17,321		17,181,618
5.00%, 11/01/32 - 10/01/49(s)			63,498		68,814,393
5.50%, 12/01/32 - 04/01/41			23,036		25,947,026
6.00%, 02/01/34 - 10/01/49(s)			23,416		26,390,261
6.50%, 05/01/40			2,699		3,107,702
Freddie Mac Mortgage-Backed Securities:
2.50%, 02/01/24 - 04/01/31			22,907		23,201,346
3.00%, 09/01/27 - 04/01/47			86,817		89,321,243
3.50%, 09/01/30 - 08/01/49			287,466		302,644,197
5.50%, 02/01/35 - 06/01/41			3,200		3,607,419
5.00%, 07/01/35 - 11/01/41			10,727		11,791,677
4.50%, 02/01/39 - 04/01/49			168,126		181,502,906
4.00%, 08/01/40 - 08/01/49			200,272		212,787,623
Ginnie Mae Mortgage-Backed Securities:
5.00%, 04/15/33 - 10/15/49(s)			93,856		99,303,274
4.00%, 04/20/39 - 10/15/49(s)			525,897		547,370,293
4.50%, 12/20/39 - 10/15/49(s)			918,369		960,241,820
3.50%, 01/15/42 - 10/15/49(s)			799,052		829,304,516
3.00%, 12/20/44 - 10/15/49(s)			760,413		779,996,750
5.50%, 10/15/49(s)			5,800		6,192,180
					12,416,412,228
Total U.S. Government Sponsored Agency Securities — 79.3% (Cost: $12,388,878,953)					12,456,935,035
U.S. Treasury Obligations — 8.3%
U.S. Treasury Bonds:
4.25%, 05/15/39			2,177		2,998,477
4.50%, 08/15/39			2,177		3,096,187
4.38%, 11/15/39			2,177		3,053,838
3.13%, 02/15/43			8,352		9,961,391
2.88%, 05/15/43 - 11/15/46			28,473		32,857,962
3.63%, 08/15/43			8,352		10,771,796
3.75%, 11/15/43			20,927		27,526,362
3.00%, 02/15/48			20,121		23,889,758
2.25%, 08/15/49			11,366		11,689,665
U.S. Treasury Inflation Indexed Notes:
0.63%, 04/15/23			16,038		16,164,609
0.50%, 04/15/24			804,236		813,861,382
U.S. Treasury Notes:
2.00%, 07/31/20 - 02/15/25			52,222		52,678,698
2.50%, 12/31/20			24,104		24,311,144
1.13%, 07/31/21			36,154		35,793,872
1.75%, 07/31/21 - 07/31/24			81,097		81,515,348
1.50%, 01/31/22 - 08/15/26			55,438		55,165,722
2.13%, 12/31/22 - 05/15/25			49,810		50,994,016
2.75%, 05/31/23			16,066		16,733,743
2.25%, 08/15/27			16,066		16,795,873

Security		Par (000)		Value
U.S. Treasury Notes: (continued) 2.88%, 08/15/28	USD		4,822	$	5,301,940
3.13%, 11/15/28			4,822		5,413,448
1.63%, 08/15/29			4,833		4,810,723
Total U.S. Treasury Obligations — 8.3% (Cost: $1,281,907,810)					1,305,385,954
		Shares
Warrants — 0.0%
Capital Markets — 0.0%
Sentinel Energy Services, Inc., Class A (Issued/Exercisable 12/22/17, 1 Share for 1 Warrant, Expires 12/22/22, Strike Price USD 11.50)(f)			145,423		47,990
Diversified Financial Services — 0.0%
Pure Acquisition Corp. (Issued/Exercisable 4/17/18, 1 Share for 1 Warrant, Expires 4/17/23, Strike Price USD 11.50)(f)			20,627		21,040
Real Estate Management & Development — 0.0%
Target Hospitality Corp. (Issued/Exercisable 3/05/18, 1 Share for 1 Warrant, Expires 3/15/24, Strike Price USD 11.50)(f)			8,280		7,121
Total Warrants — 0.0% (Cost: $132,491)					76,151
Total Long-Term Investments — 152.7% (Cost: $23,606,248,288)					23,992,525,243
Short-Term Securities — 1.3%
Mutual Funds — 1.3%
BlackRock Liquidity Funds,T-Fund, Institutional Class, 1.87%(t)(v)			205,577,418		205,577,418
SL Liquidity Series, LLC, Money Market Series, 2.13%(t)(u)(v)			1,616,527		1,616,850
Total Short-Term Investments — 1.3% (Cost: $207,194,268)					207,194,268
Options Purchased — 0.1%
(Cost: $18,532,337)					15,615,632
Total Investments Before Options Written and TBA Sale Commitments — 154.1% (Cost: $23,831,974,893)					24,215,335,143
		Par     (000)
TBA Sale Commitments — (35.0)%(s)
Mortgage-Backed Securities — (35.0)%
Fannie Mae Mortgage-Backed Securities:
2.50%, 10/01/34	USD		166,592		(167,998,192	)
3.00%, 10/01/34 - 10/01/49			1,109,720		(1,126,311,428	)
3.50%, 10/01/49			908,244		(931,588,714	)
4.00%, 10/01/49			1,402,731		(1,455,497,796	)
4.50%, 10/01/49			190,500		(200,587,863	)
5.50%, 10/01/49			1,113		(1,204,779	)

74 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio (Percentages shown are based on Net Assets)

Security		Par (000)		Value
Mortgage-Backed Securities (continued)
Ginnie Mae Mortgage-Backed Securities:
3.00%, 10/15/49	USD		375,883	$	(385,705,366	)
3.50%, 10/15/49			591,168		(612,319,054	)
4.00%, 10/15/49			260,401		(270,801,263	)
4.50%, 10/15/49			291,738		(304,861,577	)
5.00%, 10/15/49			43,232		(45,579,363	)
Total TBA Sale Commitments — (35.0)% (Proceeds: $5,500,310,481)					(5,502,455,395	)

Security	Value
Options Written — (0.1)%
(Premiums Received: $10,067,543)	$	(8,861,759	)
Total Investments Net of Options Written and TBA Sale Commitments — 119.0% (Cost: $18,321,596,869)		18,704,017,989
Liabilities in Excess of Other Assets — (19.0)%		(2,991,186,585	)
Net Assets — 100.0%	$	15,712,831,404

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

^(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)  Security is valued using significant unobservable inputs and is classified as Level 3 in the fair value hierarchy.

^(d)  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.

^(e)  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.

^(f)  Non-income producing security.

^(g)  Convertible security.

^(h)  Zero-coupon bond.

⁽ⁱ⁾  Issuer filed for bankruptcy and/or is in default.

^(j)  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.

^(k)  Perpetual security with no stated maturity date.

^(l)  Payment-in-kind security which may pay interest/dividends in additional par/shares and/or in cash. Rates shown are the current rate and possible payment rates.

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

⁽ⁿ⁾  U.S. dollar denominated security issued by foreign domiciled entity.

^(o)  Fixed rate.

^(p)  Represents an unsettled loan commitment at period end. Certain details associated with this purchase are not known prior to the settlement date, including coupon rate.

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

^(r)  Amount is less than $500.

^(s)  Represents or includes a TBA transaction.

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

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

^(v)  During the year ended September 30, 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 Fund were as follows:

Affiliated Persons and/or Related Parties	Par/Shares Held at 09/30/18		Par/Shares Purchased		Par/Shares Sold			Par/Shares Held at 09/30/19		Value at 09/30/19		Income			Net Realized Gain (Loss)(a)			Change in   Unrealized   Appreciation   (Depreciation)
BlackRock Capital Finance LP, Series1997-R2, Class AP	$	3,374	$	—	$	—		$	3,374	$	3,056	$	—		$	—			$	63
BlackRock Liquidity Funds,T-Fund, Institutional Class(b)		791,503,000		—		(585,925,582	)		205,577,418		205,577,418		13,552,292			—				—
iShares ChinaLarge-Cap ETF(c)		—		40,000		(40,000	)		—		—		—			3,614				—
iShares MSCI Emerging Markets ETF		—		178,000		(40,000	)		138,000		5,640,060		—			28,390				(128,478	)
iShares iBoxx $ High Yield Corporate Bond ETF(c)		—		2,121,807		(2,121,807	)		—		—		270,501			100,959				—
iShares JPMorgan USD Emerging Markets Bond ETF(c)		1,201,638		1,093,793		(2,295,431	)		—		—		2,969,209			(4,216,578	)			(603,443	)
SL Liquidity Series, LLC, Money Market Series(b)		8,009,890		—		(6,393,363	)		1,616,527		1,616,850		91,969	(d)		(454	)			(416	)
										$	212,837,384	$	16,883,971		$	(4,084,069	)		$	(732,274	)

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

^(b)  Represents net shares sold.

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

^(d)  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.

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 75

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

For Master Portfolio compliance purposes, the Master Portfolio’s industry classifications refer to one or more of the industrysub-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 industrysub-classifications for reporting ease.

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
Euro-BTP Italian Government Bond		375		12/06/19		$	59,610		$	260,596
Euro-OAT		254		12/06/19			47,150			(227,656	)
Euro-Schatz		3		12/06/19			367			(35	)
Euro Dollar		52		12/16/19			12,745			(13,703	)
U.S. Treasury Bonds (30 Year)		106		12/19/19			17,205			(43,239	)
U.S. Ultra Treasury Bonds		5,135		12/19/19			985,439			(10,480,277	)
U.S. Ultra Treasury Bonds (10 Year)		2,828		12/19/19			402,725			1,409,078
U.S. Treasury Notes (2 Year)		6,884		12/31/19			1,483,502			2,472,603
U.S. Treasury Notes (5 Year)		7,457		12/31/19			888,490			2,163,097
Three Month Sterling		129		06/17/20			19,712			38,052
										(4,421,484	)
Short Contracts
Euro-Bobl		973		12/06/19			143,860			685,045
Euro-Bund		1,066		12/06/19			202,459			714,749
Euro-Buxl		439		12/06/19			104,072			1,519,211
Canadian Government Bonds (10 Year)		276		12/18/19			29,707			(118,514	)
U.S. Treasury Notes (10 Year)		5,211		12/19/19			679,058			(2,457,150	)
E-Mini S&P 500 Index		431		12/20/19			64,187			390,898
NASDAQ 100E-Mini Index		35		12/20/19			5,439			(30,440	)
										703,799
									$	(3,717,685	)

Forward Foreign Currency Exchange Contracts

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized     Appreciation     (Depreciation)
CAD	3,389,253	EUR	2,335,000	Deutsche Bank AG		10/01/19		$	13,012
BRL	38,774,461	EUR	8,455,000	BNP Paribas S.A.		10/02/19			113,690
BRL	61,794,459	EUR	13,474,000	BNP Paribas S.A.		10/02/19			181,892
BRL	1,927,906	USD	460,000	Citibank N.A.		10/02/19			3,933
USD	3,110,000	BRL	12,793,918	Morgan Stanley & Co. International PLC		10/02/19			31,260
USD	606,076,701	EUR	549,706,000	Bank of America N.A.		10/03/19			6,779,011
USD	121,719	JPY	13,152,000	Citibank N.A.		10/03/19			56
INR	154,018,900	USD	2,135,000	BNP Paribas S.A.		10/07/19			36,618
USD	1,156,000	ARS	57,568,800	Citibank N.A.		10/07/19			190,995
USD	24,707,250	CAD	32,714,129	Deutsche Bank AG		10/07/19			11,768
USD	24,707,250	EUR	22,649,137	Goldman Sachs International		10/07/19			6,936
USD	24,707,250	GBP	20,034,584	Bank of America N.A.		10/07/19			66,401
USD	445,000	ARS	26,522,000	JPMorgan Chase Bank N.A.		10/09/19			421
USD	725,627	CHF	712,173	Morgan Stanley & Co. International PLC		10/09/19			11,476
USD	7,514,725	EUR	6,807,678	HSBC Bank PLC		10/09/19			89,336
KRW	2,816,733,068	USD	2,352,000	BNP Paribas S.A.		10/10/19			3,500
TRY	13,707,593	USD	2,355,000	UBS AG		10/10/19			63,962
USD	2,352,000	KRW	2,802,408,000	BNP Paribas S.A.		10/10/19			8,480
USD	3,339,000	KRW	3,979,212,514	UBS AG		10/10/19			11,374
USD	490,000	ARS	29,522,500	Goldman Sachs International		10/15/19			6,237
USD	4,677,000	SGD	6,452,300	BNP Paribas S.A.		10/15/19			7,860

76 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized     Appreciation     (Depreciation)
USD	3,097,000	CLP	2,199,179,700	Citibank N.A.		10/16/19		$	79,941
USD	3,064,000	CLP	2,178,197,600	Citibank N.A.		10/23/19			75,306
USD	3,907,676	COP	13,442,406,850	Citibank N.A.		10/23/19			49,029
USD	3,999,813	COP	13,849,352,500	Credit Suisse International		10/23/19			24,352
USD	7,019,067	COP	23,942,036,050	Credit Suisse International		10/23/19			146,497
USD	3,902,005	COP	13,442,406,850	JPMorgan Chase Bank N.A.		10/23/19			43,358
USD	5,118,016	COP	17,649,477,000	JPMorgan Chase Bank N.A.		10/23/19			51,728
USD	3,131,000	COP	10,667,317,000	JPMorgan Chase Bank N.A.		10/23/19			68,943
USD	3,125,000	COP	10,818,750,000	Morgan Stanley & Co. International PLC		10/23/19			19,474
USD	5,128,754	COP	17,649,477,000	NatWest Markets PLC		10/23/19			62,465
USD	3,064,000	COP	10,383,896,000	NatWest Markets PLC		10/23/19			83,299
USD	7,023,185	COP	23,942,036,050	NatWest Markets PLC		10/23/19			150,615
USD	2,323,000	ZAR	34,205,762	Morgan Stanley & Co. International PLC		10/23/19			71,644
ZAR	107,875,163	USD	7,097,751	Citibank N.A.		10/23/19			2,381
USD	3,144,000	RUB	202,096,320	Bank of America N.A.		10/25/19			38,407
TWD	95,560,307	USD	3,083,000	UBS AG		10/30/19			2,726
BRL	3,401,667	USD	811,000	JPMorgan Chase Bank N.A.		11/04/19			5,648
USD	312,946	EUR	285,000	Goldman Sachs International		11/05/19			1,437
RUB	503,104,740	USD	7,628,000	JPMorgan Chase Bank N.A.		11/06/19			90,745
RUB	654,793,520	USD	9,848,000	Morgan Stanley & Co. International PLC		11/06/19			197,989
USD	3,005,265	EUR	2,744,000	JPMorgan Chase Bank N.A.		11/06/19			5,833
USD	78,448,040	MXN	1,537,126,594	BNP Paribas S.A.		11/06/19			1,050,625
USD	3,179,000	MXN	62,710,544	HSBC Bank PLC		11/06/19			21,398
USD	7,816,000	MXN	153,736,812	HSBC Bank PLC		11/06/19			75,042
USD	7,619,000	RUB	496,073,090	Bank of America N.A.		11/06/19			8,136
USD	2,381,000	RUB	154,145,940	Bank of America N.A.		11/06/19			16,059
USD	4,928,500	RUB	316,138,633	Bank of America N.A.		11/06/19			78,230
USD	4,928,500	RUB	316,877,908	Citibank N.A.		11/06/19			66,888
USD	720,000	ARS	50,580,000	Goldman Sachs International		11/29/19			6,410
USD	377,068	CNH	2,690,000	Bank of America N.A.		12/12/19			1,029
USD	376,655	CNH	2,686,079	Bank of America N.A.		12/12/19			1,165
USD	377,205	CNH	2,690,000	Bank of America N.A.		12/12/19			1,167
USD	2,608,453	EUR	2,345,421	Barclays Bank PLC		12/12/19			37,796
USD	9,578,065	JPY	1,024,374,026	Bank of America N.A.		12/12/19			54,581
USD	373,365	KRW	444,098,451	UBS AG		12/12/19			1,310
USD	43,851,570	EUR	33,810,000	Deutsche Bank AG		12/13/19			6,791,274
CAD	19,717,541	AUD	21,557,000	Citibank N.A.		12/18/19			316,313
CAD	31,109	USD	23,460	Citibank N.A.		12/18/19			53
CHF	2,950,809	EUR	2,695,000	JPMorgan Chase Bank N.A.		12/18/19			21,980
EUR	24,611,000	CAD	35,689,272	JPMorgan Chase Bank N.A.		12/18/19			15,323
JPY	1,952,319,652	ZAR	266,765,000	Bank of America N.A.		12/18/19			726,843
NOK	121,615,000	SEK	129,596,471	Bank of America N.A.		12/18/19			147,857
USD	4,033,462	AUD	5,879,931	BNP Paribas S.A.		12/18/19			54,864
USD	1,349,462	CHF	1,333,325	BNP Paribas S.A.		12/18/19			4,106
USD	18,742,175	EUR	16,917,000	Bank of America N.A.		12/18/19			190,248
USD	15,014,782	EUR	13,474,000	JPMorgan Chase Bank N.A.		12/18/19			238,600
USD	1,295,309	EUR	1,174,711	NatWest Markets PLC		12/18/19			7,069
USD	28,654,193	EUR	25,930,000	Standard Chartered Bank		12/18/19			218,212
USD	5,283	GBP	4,218	BNP Paribas S.A.		12/18/19			80
USD	4,012,508	GBP	3,231,405	JPMorgan Chase Bank N.A.		12/18/19			26,331
USD	22,975,000	JPY	2,469,261,100	BNP Paribas S.A.		12/18/19			4,111
USD	3,130,000	JPY	336,399,880	Royal Bank of Canada		12/18/19			560

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 77

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized     Appreciation     (Depreciation)
USD	40,667	NOK	367,510	Bank of America N.A.		12/18/19		$	220
USD	12,015,471	NZD	18,862,000	BNP Paribas S.A.		12/18/19			182,838
USD	13,581,341	NZD	21,557,000	Citibank N.A.		12/18/19			58,063
USD	945	NZD	1,502	UBS AG		12/18/19			3
USD	2,857,825	EUR	2,500,000	NatWest Markets PLC		01/15/20			110,165
USD	2,856,320	EUR	2,500,000	Royal Bank of Canada		01/17/20			108,295
USD	44,135,574	EUR	33,810,000	Deutsche Bank AG		02/25/20			6,874,922
JPY	4,504,440,000	USD	41,738,695	JPMorgan Chase Bank N.A.		03/16/20			414,402
USD	44,963,466	JPY	4,504,440,000	HSBC Bank PLC		03/16/20			2,810,368
									29,652,971
CAD	35,527,886	EUR	24,611,000	JPMorgan Chase Bank N.A.		10/01/19			(10,029	)
EUR	26,946,000	CAD	39,004,335	Deutsche Bank AG		10/01/19			(68,798	)
BRL	40,209,384	USD	9,848,000	Citibank N.A.		10/02/19			(171,977	)
BRL	6,485,932	USD	1,569,000	Citibank N.A.		10/02/19			(8,219	)
BRL	16,081,982	USD	3,921,000	Morgan Stanley & Co. International PLC		10/02/19			(51,017	)
EUR	10,778,500	BRL	49,502,417	BNP Paribas S.A.		10/02/19			(162,363	)
EUR	6,288,500	BRL	28,881,194	BNP Paribas S.A.		10/02/19			(94,728	)
EUR	4,490,000	BRL	20,579,466	BNP Paribas S.A.		10/02/19			(57,587	)
USD	10,308,000	BRL	42,955,498	BNP Paribas S.A.		10/02/19			(28,850	)
USD	811,000	BRL	3,395,170	JPMorgan Chase Bank N.A.		10/02/19			(6,017	)
USD	1,569,000	BRL	6,536,297	Morgan Stanley & Co. International PLC		10/02/19			(3,901	)
USD	720,000	ARS	47,880,000	JPMorgan Chase Bank N.A.		10/04/19			(82,595	)
USD	715,000	ARS	46,832,500	Morgan Stanley & Co. International PLC		10/04/19			(70,036	)
ARS	73,609,200	USD	1,524,000	BNP Paribas S.A.		10/07/19			(290,116	)
ARS	20,880,000	USD	360,000	Goldman Sachs International		10/07/19			(9,996	)
ARS	20,826,000	USD	360,000	Morgan Stanley & Co. International PLC		10/07/19			(10,901	)
CAD	21,812,005	USD	16,471,500	Deutsche Bank AG		10/07/19			(5,893	)
CAD	10,907,856	USD	8,235,750	TD Securities, Inc.		10/07/19			(1,548	)
EUR	15,055,672	USD	16,471,500	Standard Chartered Bank		10/07/19			(52,338	)
EUR	7,518,462	USD	8,235,750	Standard Chartered Bank		10/07/19			(36,392	)
GBP	13,333,738	USD	16,471,500	UBS AG		10/07/19			(72,127	)
GBP	6,664,528	USD	8,235,750	UBS AG		10/07/19			(38,943	)
USD	2,135,000	INR	153,399,750	HSBC Bank PLC		10/07/19			(27,889	)
AUD	24,352,975	USD	16,471,500	Deutsche Bank AG		10/08/19			(29,549	)
AUD	12,152,808	USD	8,235,750	HSBC Bank PLC		10/08/19			(30,762	)
USD	24,707,250	AUD	36,623,327	Morgan Stanley & Co. International PLC		10/08/19			(19,050	)
EUR	1,806,000	USD	1,990,738	BNP Paribas S.A.		10/09/19			(20,867	)
USD	635,000	ARS	38,481,000	Morgan Stanley & Co. International PLC		10/09/19			(10,043	)
USD	2,355,000	TRY	13,730,561	UBS AG		10/10/19			(68,015	)
ARS	86,275,000	USD	1,750,000	JPMorgan Chase Bank N.A.		10/15/19			(336,277	)
SGD	6,454,335	USD	4,677,000	BNP Paribas S.A.		10/15/19			(6,387	)
USD	700,000	ARS	48,300,000	BNP Paribas S.A.		10/15/19			(91,455	)
USD	1,400,000	ARS	98,000,000	Goldman Sachs International		10/15/19			(205,852	)
USD	700,000	ARS	47,600,000	Goldman Sachs International		10/15/19			(79,985	)
CLP	2,764,233,780	USD	3,894,000	NatWest Markets PLC		10/16/19			(101,743	)
CLP	743,142,560	USD	1,026,440	JPMorgan Chase Bank N.A.		10/23/19			(6,778	)
CLP	732,050,880	USD	1,011,120	JPMorgan Chase Bank N.A.		10/23/19			(6,677	)
CLP	743,655,780	USD	1,026,440	UBS AG		10/23/19			(6,074	)
COP	12,729,852,000	USD	3,732,000	Barclays Bank PLC		10/23/19			(77,892	)
COP	10,393,532,000	USD	3,097,000	Citibank N.A.		10/23/19			(113,533	)
COP	7,780,674,500	USD	2,294,000	UBS AG		10/23/19			(60,555	)
USD	6,978,277	ZAR	107,875,163	HSBC Bank PLC		10/23/19			(121,854	)

78 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized     Appreciation     (Depreciation)
ZAR	34,391,550	USD	2,323,000	Bank of America N.A.		10/23/19		$	(59,416	)
EUR	2,853,000	USD	3,152,327	Citibank N.A.		10/28/19			(35,724	)
USD	3,083,000	TWD	96,343,750	BNP Paribas S.A.		10/30/19			(28,024	)
BRL	32,759,451	USD	7,911,000	Citibank N.A.		11/04/19			(46,347	)
BRL	2,847,293	USD	689,000	Citibank N.A.		11/04/19			(5,443	)
BRL	10,250,955	USD	2,475,000	Deutsche Bank AG		11/04/19			(14,025	)
BRL	13,208,000	USD	3,175,000	JPMorgan Chase Bank N.A.		11/04/19			(4,119	)
USD	720,000	ARS	53,820,000	BNP Paribas S.A.		11/04/19			(101,583	)
USD	360,000	ARS	26,226,000	BNP Paribas S.A.		11/04/19			(40,350	)
USD	2,349,000	BRL	9,845,129	Citibank N.A.		11/04/19			(14,548	)
EUR	2,744,000	USD	3,025,050	JPMorgan Chase Bank N.A.		11/06/19			(25,618	)
IDR	163,343,950,000	USD	11,495,000	BNP Paribas S.A.		11/06/19			(34,519	)
IDR	110,768,352,000	USD	7,816,000	Citibank N.A.		11/06/19			(44,309	)
MXN	153,148,267	USD	7,816,000	BNP Paribas S.A.		11/06/19			(104,677	)
MXN	80,492,974	USD	4,108,000	BNP Paribas S.A.		11/06/19			(55,017	)
USD	20,372,047	IDR	292,990,777,792	Bank of America N.A.		11/06/19			(184,670	)
USD	9,724,387	IDR	141,100,857,267	Citibank N.A.		11/06/19			(175,482	)
USD	6,277,424	IDR	91,148,198,746	Citibank N.A.		11/06/19			(117,684	)
USD	5,801,553	IDR	83,582,975,242	Goldman Sachs International		11/06/19			(62,767	)
USD	11,495,000	IDR	169,838,625,000	JPMorgan Chase Bank N.A.		11/06/19			(421,159	)
USD	11,495,000	MXN	229,483,881	Citibank N.A.		11/06/19			(59,975	)
USD	32,487,889	RUB	2,142,202,637	Morgan Stanley & Co. International PLC		11/06/19			(378,263	)
USD	3,896,035	RUB	261,385,000	Morgan Stanley & Co. International PLC		11/06/19			(114,192	)
ARS	59,881,000	USD	1,165,000	HSBC Bank PLC		11/13/19			(276,131	)
ARS	30,039,750	USD	585,000	HSBC Bank PLC		11/13/19			(139,092	)
USD	715,000	ARS	53,088,750	Morgan Stanley & Co. International PLC		11/29/19			(33,984	)
USD	5,623,010	HKD	44,069,776	Bank of America N.A.		12/12/19			(4,130	)
USD	1,245,893	TWD	38,600,260	Bank of America N.A.		12/12/19			(3,511	)
EUR	33,810,000	USD	41,367,211	JPMorgan Chase Bank N.A.		12/13/19			(4,306,916	)
AUD	21,557,000	CAD	19,620,427	Citibank N.A.		12/18/19			(242,913	)
AUD	25,506,000	NZD	27,566,375	JPMorgan Chase Bank N.A.		12/18/19			(34,734	)
AUD	900,000	NZD	972,630	JPMorgan Chase Bank N.A.		12/18/19			(1,180	)
AUD	540,000	NZD	583,023	JPMorgan Chase Bank N.A.		12/18/19			(360	)
AUD	1,161,449	USD	786,223	JPMorgan Chase Bank N.A.		12/18/19			(340	)
BRL	73,428,672	USD	17,984,000	UBS AG		12/18/19			(395,621	)
CHF	1,283,785	USD	1,307,059	JPMorgan Chase Bank N.A.		12/18/19			(11,690	)
EUR	2,695,000	CHF	2,941,458	Citibank N.A.		12/18/19			(12,544	)
EUR	2,234,101	USD	2,486,923	BNP Paribas S.A.		12/18/19			(36,909	)
EUR	5,389,000	USD	5,986,771	HSBC Bank PLC		12/18/19			(76,956	)
EUR	8,085,000	USD	8,960,670	JPMorgan Chase Bank N.A.		12/18/19			(94,303	)
EUR	25,930,000	USD	28,600,738	Standard Chartered Bank		12/18/19			(164,758	)
EUR	5,389,000	USD	5,983,202	Standard Chartered Bank		12/18/19			(73,387	)
JPY	3,344,925,162	USD	31,127,000	Citibank N.A.		12/18/19			(10,037	)
JPY	226,738,251	USD	2,116,695	UBS AG		12/18/19			(7,408	)
NOK	36,008,614	USD	4,039,217	BNP Paribas S.A.		12/18/19			(76,194	)
NZD	6,364,388	USD	4,037,778	BNP Paribas S.A.		12/18/19			(45,228	)
NZD	18,862,000	USD	11,996,251	Deutsche Bank AG		12/18/19			(163,618	)
NZD	21,557,000	USD	13,551,575	JPMorgan Chase Bank N.A.		12/18/19			(28,297	)
SEK	130,393,414	NOK	121,615,000	JPMorgan Chase Bank N.A.		12/18/19			(66,458	)
SEK	27,907,245	USD	2,893,310	BNP Paribas S.A.		12/18/19			(42,903	)
SEK	10,805,999	USD	1,115,992	NatWest Markets PLC		12/18/19			(12,282	)
USD	17,984,000	BRL	75,298,468	JPMorgan Chase Bank N.A.		12/18/19			(52,251	)

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 79

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Currency Purchased		Currency Sold		Counterparty	Settlement Date		Unrealized       Appreciation       (Depreciation)
USD	4,039,281	CAD	5,351,660	BNP Paribas S.A.		12/18/19		$	(5,538	)
USD	4,034,740	JPY	434,003,989	BNP Paribas S.A.		12/18/19			(2,685	)
USD	5,022,000	JPY	539,859,425	Citibank N.A.		12/18/19			(171	)
ZAR	150,675,000	JPY	1,088,310,457	BNP Paribas S.A.		12/18/19			(276,536	)
ZAR	60,100,000	JPY	436,656,550	BNP Paribas S.A.		12/18/19			(134,120	)
ZAR	32,095,000	JPY	230,917,106	BNP Paribas S.A.		12/18/19			(50,515	)
ZAR	6,685,000	JPY	48,690,197	BNP Paribas S.A.		12/18/19			(16,038	)
ZAR	9,810,000	JPY	70,869,402	JPMorgan Chase Bank N.A.		12/18/19			(18,123	)
ZAR	7,400,000	JPY	53,388,040	JPMorgan Chase Bank N.A.		12/18/19			(13,010	)
EUR	5,000,000	USD	5,659,655	NatWest Markets PLC		01/17/20			(163,606	)
EUR	33,810,000	USD	41,665,584	JPMorgan Chase Bank N.A.		02/25/20			(4,404,933	)
									(16,382,929	)
Net Unrealized Appreciation								$	13,270,042

Interest Rate Caps Purchased

Reference Entity	Exercise Rate	Counterparty	Expiration Date	Notional Amount (000)			Value		Premiums Paid (Received)		Unrealized      Appreciation      (Depreciation)
10Y-2Y CMS Index Cap	0.50%	Citibank N.A.	03/13/20		USD	1,017,480	$	77,898	$	391,730		$	(313,832	)
10Y-2Y CMS Index Cap	0.40%	Goldman Sachs International	03/31/20		USD	860,000		171,923		718,100			(546,177	)
							$	249,821	$	1,109,830		$	(860,009	)

Exchange-Traded Options Purchased

Description	Number of Contracts	Expiration Date	Exercise Price				Notional Amount (000)		Value
Call
SPDR S&P 500 ETF Trust	1,682	10/18/19	USD		299.00	USD		49,917	$	489,462
U.S. Treasury Notes (10 Year)	258	10/25/19	USD		131.00	USD		33,621		104,813
DAX Performance-Index	309	12/20/19	EUR		13,700.00	EUR		19,201		6,989
EURO STOXX 50 Index	1,073	12/20/19	EUR		3,850.00	EUR		38,300		50,289
iShares MSCI Emerging Markets Index ETF	1,097	12/20/19	USD		45.00	USD		4,483		14,810
Caesars Entertainment Corp.	14,489	01/17/20	USD		12.00	USD		16,894		420,181
VanEck Vectors JPMorgan EM Local Currency Bond ETF	11,684	01/17/20	USD		37.00	USD		38,557		87,630
DAX Performance-Index	415	03/20/20	EUR		13,600.00	EUR		25,788		155,489
EURO STOXX 50 Index	1,443	03/20/20	EUR		3,800.00	EUR		51,507		554,413
SPDR S&P 500 ETF Trust	3,347	06/30/20	USD		325.00	USD		99,329		1,342,147
Caesars Entertainment Corp.	11,693	01/15/21	USD		12.00	USD		13,634		906,208
Market Vectors Gold Miners ETF	2,288	01/15/21	USD		30.00	USD		6,111		661,232
										4,793,663
Put				��
SPDR S&P 500 ETF Trust	2,346	10/07/19	USD		290.00	USD		69,622		97,359
SPDR S&P 500 ETF Trust	2,346	10/18/19	USD		290.00	USD		69,622		397,647
SPDR S&P 500 ETF Trust	2,346	10/30/19	USD		290.00	USD		69,622		619,344
Energy Select Sector SPDR ETF	2,920	12/20/19	USD		56.00	USD		17,286		386,900
Market Vectors Gold Miners ETF	11,440	12/20/19	USD		23.00	USD		30,556		331,760

80 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Description	Number of Contracts	Expiration Date		Exercise Price		Notional Amount (000)		Value
SPDR S&P 500 ETF Trust	187		12/20/19	USD	297.00	USD	5,550	$	157,267
Caesars Entertainment Corp.	499		01/17/20	USD	10.00	USD	582		4,242
									1,994,519
								$	6,788,182

OTC Barrier Options Purchased

Description

Type of Option

Counterparty

Number of Contracts

Expiration Date

Exercise Price

Barrier Price/Range

Notional Amount (000)

Value

Put

EUR Currency

One-Touch

Bank of America N.A.

—

11/27/19

USD

1.09

USD1.09

EUR

1,130

$

487,620

EUR Currency

Under-and-In

BNP Paribas S.A.

—

12/20/19

USD

1.11

USD1.16

EUR

44,900

1,778

$

489,398

OTC Options Purchased

Description	Counterparty	Number of Contracts	Expiration Date		Exercise Price		Notional Amount (000)		Value
Call
EUR Currency(a)	BNP Paribas S.A.	—		10/11/19	USD	1.14	EUR	2,763	$	—
USD Currency	BNP Paribas S.A.	—		10/11/19	BRL	4.07	USD	10,506		263,178
EUR Currency	Morgan Stanley & Co. International PLC	—		10/23/19	CHF	1.13	EUR	26,946		854
EUR Currency	Bank of America N.A.	—		11/08/19	USD	1.14	EUR	3,800		1,353
USD Currency	Morgan Stanley & Co. International PLC	—		11/14/19	TWD	30.75	USD	6,220		62,864
										328,249
Put
USD Currency	Citibank N.A.	—		10/04/19	ZAR	14.75	USD	2,928		256
USD Currency	Morgan Stanley & Co. International PLC	—		10/04/19	ZAR	14.40	USD	3,074		1
USD Currency	Deutsche Bank AG	—		10/07/19	BRL	3.93	USD	5,832		22
EUR Currency	UBS AG	—		10/11/19	USD	1.12	EUR	5,526		126,972
USD Currency	Deutsche Bank AG	—		10/18/19	RUB	66.25	USD	4,677		97,927
USD Currency	BNP Paribas S.A.	—		10/29/19	BRL	4.08	USD	3,145		17,799
USD Currency	Morgan Stanley & Co. International PLC	—		10/29/19	BRL	4.08	USD	3,145		17,718
USD Currency	Bank of America N.A.	—		10/30/19	MXN	20.15	USD	4,722		102,774
USD Currency	HSBC Bank PLC	—		10/30/19	MXN	20.00	USD	11,788		191,696
USD Currency	Morgan Stanley & Co. International PLC	—		10/30/19	MXN	19.50	USD	18,861		74,639
USD Currency	BNP Paribas S.A.	—		11/04/19	BRL	4.12	USD	3,152		31,515
USD Currency	Deutsche Bank AG	—		11/07/19	BRL	3.90	USD	13,752		15,394
EUR Currency	NatWest Markets PLC	—		11/08/19	USD	1.11	EUR	7,700		141,837
USD Currency	HSBC Bank PLC	—		11/14/19	BRL	4.08	USD	6,219		50,429

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 81

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Description	Counterparty	Number of Contracts		Expiration Date		Exercise Price		Notional Amount (000)		Value
USD Currency	Bank of America N.A.		—		11/18/19	INR	71.50	USD	4,671	$	62,456
USD Currency	Bank of America N.A.		—		11/18/19	RUB	64.50	USD	4,671		36,433
USD Currency	JPMorgan Chase Bank N.A.		—		11/22/19	BRL	3.65	USD	21,603		807
USD Currency(a)	JPMorgan Chase Bank N.A.		—		11/22/19	BRL	3.40	USD	9,001		1
EUR Currency	BNP Paribas S.A.		—		11/27/19	USD	1.11	EUR	57,240		1,079,967
EUR Currency	BNP Paribas S.A.		—		11/27/19	USD	1.09	EUR	34,410		261,841
USD Currency	BNP Paribas S.A.		—		12/17/19	JPY	106.00	USD	122,025		906,199
USD Currency	Royal Bank of Canada		—		12/17/19	JPY	106.00	USD	14,323		106,367
USD Currency	Deutsche Bank AG		—		12/20/19	JPY	106.00	USD	120,342		934,571
EUR Currency	JPMorgan Chase Bank N.A.		—		04/29/20	USD	1.11	EUR	29,665		569,037
											4,826,658
										$	5,154,907

^(a) Security is valued using significant unobservable inputs and is classified as Level 3 in the fair value hierarchy.

OTC Interest Rate Swaptions Purchased

Paid by the Fund

Received by the Fund

Counterparty

Expiration Date

Exercise Rate

Notional Amount (000)

Value

Description

Rate

Frequency

Rate

Frequency

Call

10-Year Interest Rate Swap, 03/19/30

3-month LIBOR, 2.09%

Quarterly

1.70%

Semi-Annual

Bank of America N.A.

03/17/20

1.70%

USD

62,112

$

1,573,104

10-Year Interest Rate Swap, 03/19/30

3-month LIBOR, 2.09%

Quarterly

1.70%

Semi-Annual

Bank of America N.A.

03/17/20

1.70%

USD

4,176

105,765

1,678,869

Put

10-Year Interest Rate Swap, 03/19/30

1.70%

Semi-Annual

3-month LIBOR, 2.09%

Quarterly

Bank of America N.A.

03/17/20

1.70%

USD

62,112

746,870

10-Year Interest Rate Swap, 03/19/30

1.70%

Semi-Annual

3-month LIBOR, 2.09%

Quarterly

Bank of America N.A.

03/17/20

1.70%

USD

4,176

50,215

10-Year Interest Rate Swap, 03/25/30

1.79%

Semi-Annual

3-month LIBOR, 2.09%

Quarterly

Deutsche Bank AG

03/23/20

1.79%

USD

49,348

457,370

1,254,455

$

2,933,324

Exchange-Traded Options Written

Description	Number of Contracts	Expiration Date	Exercise Price		Notional Amount (000)		Value
Call
PowerShares QQQ Trust, Series 1 ETF	1,552	10/04/19	USD	194.00	USD	29,303	$	(7,760	)
iShares Transportation Average ETF	467	10/18/19	USD	187.00	USD	8,693		(126,090	)
PowerShares QQQ Trust, Series 1 ETF	467	10/18/19	USD	189.00	USD	8,817		(151,075	)
SPDR KBW Regional Banking ETF	1,832	10/18/19	USD	53.50	USD	9,671		(130,072	)
SPDR S&P Retail ETF	2,336	10/18/19	USD	42.50	USD	9,912		(200,896	)

82 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Description	Number of Contracts	Expiration Date	Exercise Price		Notional Amount (000)		Value
SPDR S&P 500 ETF Trust	3	10/21/19	USD	297.00	USD	89	$	(1,307	)
U.S. Treasury Notes (10 Year)	94	10/25/19	USD	132.50	USD	12,249		(10,281	)
U.S. Treasury Notes (10 Year)	308	10/25/19	USD	132.00	USD	40,136		(52,938	)
Energy Select Sector SPDR ETF	940	11/15/19	USD	60.00	USD	5,565		(132,540	)
U.S. Treasury Notes (10 Year)	261	11/22/19	USD	132.00	USD	34,012		(106,031	)
								(918,990	)
Put
CME CBOT U.S. Treasury Notes (10 Year) Week 1	801	10/04/19	USD	129.25	USD	104,380		(37,547	)
PowerShares QQQ Trust, Series 1 ETF	1,552	10/04/19	USD	185.00	USD	29,303		(58,200	)
SPDR S&P Oil & Gas Explore & Production ETF	2,325	10/18/19	USD	21.00	USD	5,199		(66,263	)
U.S. Treasury Notes (10 Year)	260	10/25/19	USD	129.00	USD	33,881		(56,875	)
U.S. Treasury Notes (2 Year)	1,487	10/25/19	USD	107.38	USD	320,449		(92,938	)
SPDR S&P 500 ETF Trust	5,864	10/30/19	USD	282.00	USD	174,026		(847,348	)
SPDR S&P 500 ETF Trust	1,339	12/20/19	USD	255.00	USD	39,738		(174,070	)
Technology Select Sector SPDR Fund	3,074	12/20/19	USD	72.00	USD	24,755		(287,419	)
SPDR S&P 500 ETF Trust	915	12/31/19	USD	275.00	USD	27,154		(342,210	)
SPDR S&P 500 ETF Trust	2,346	12/31/19	USD	265.00	USD	69,622		(568,905	)
SPDR S&P 500 ETF Trust	3,347	06/30/20	USD	250.00	USD	99,329		(1,862,602	)
								(4,394,377	)
							$	(5,313,367	)

OTC Options Written

Description	Counterparty	Number of Contracts		Expiration Date		Exercise Price			Notional Amount (000)			Value
Call
USD Currency	Deutsche Bank AG		—		10/07/19		BRL	4.20		USD	2,916	$	(12,056	)
EUR Currency(a)	UBS AG		—		10/11/19		USD	1.14		EUR	2,763		—
USD Currency	BNP Paribas S.A.		—		10/11/19		BRL	4.22		USD	21,011		(81,754	)
USD Currency	Deutsche Bank AG		—		10/18/19		RUB	70.00		USD	2,338		(98	)
USD Currency	BNP Paribas S.A.		—		10/29/19		BRL	4.30		USD	1,573		(8,632	)
USD Currency	Morgan Stanley & Co. International PLC		—		10/29/19		BRL	4.30		USD	1,573		(8,632	)
USD Currency	BNP Paribas S.A.		—		11/04/19		BRL	4.30		USD	1,576		(10,545	)
USD Currency	Deutsche Bank AG		—		11/07/19		BRL	4.10		USD	2,453		(66,711	)
EUR Currency	NatWest Markets PLC		—		11/08/19		USD	1.14		EUR	3,800		(1,353	)
USD Currency	Bank of America N.A.		—		11/18/19		RUB	66.00		USD	2,336		(23,128	)
USD Currency	JPMorgan Chase Bank N.A.		—		11/22/19		BRL	3.95		USD	6,751		(389,614	)
													(602,523	)
Put
USD Currency	Citibank N.A.		—		10/04/19		ZAR	14.40		USD	4,392		(1	)
	Deutsche Bank
USD Currency(a)	AG		—		10/07/19		BRL	3.80		USD	5,832		(1	)
EUR Currency	UBS AG		—		10/11/19		USD	1.10		EUR	4,145		(23,110	)
USD Currency	BNP Paribas S.A.		—		10/11/19		BRL	3.95		USD	10,506		(295	)
USD Currency	BNP Paribas S.A.		—		10/29/19		BRL	3.92		USD	3,145		(1,820	)

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 83

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Description	Counterparty	Number of     Contracts	Expiration     Date		Exercise Price		Notional Amount (000)		Value
USD Currency	Morgan Stanley & Co. International PLC	—		10/29/19	BRL	3.92	USD	3,145		$	(1,809	)
USD Currency	Bank of America N.A.	—		10/30/19	MXN	19.65	USD	7,083			(45,891	)
USD Currency	HSBC Bank PLC	—		10/30/19	MXN	19.50	USD	18,861			(74,040	)
USD Currency	BNP Paribas S.A.	—		11/04/19	BRL	4.00	USD	4,728			(12,531	)
EUR Currency	HSBC Bank PLC	—		11/08/19	USD	1.11	EUR	7,700			(141,839	)
USD Currency	HSBC Bank PLC	—		11/14/19	BRL	3.99	USD	9,329			(30,349	)
USD Currency	Bank of America N.A.	—		11/18/19	RUB	62.90	USD	7,007			(13,017	)
USD Currency	Bank of America N.A.	—		11/18/19	INR	70.50	USD	7,007			(40,994	)
USD Currency	JPMorgan Chase Bank N.A.	—		11/22/19	BRL	3.50	USD	27,004			(48	)
EUR Currency	Citibank N.A.	—		11/27/19	USD	1.09	EUR	34,410			(259,086	)
EUR Currency	HSBC Bank PLC	—		11/27/19	USD	1.09	EUR	35,200			(270,687	)
EUR Currency	NatWest Markets PLC	—		11/27/19	USD	1.11	EUR	57,240			(1,079,945	)
USD Currency	BNP Paribas S.A.	—		12/17/19	JPY	102.00	USD	136,348			(277,955	)
USD Currency	Deutsche Bank AG	—		12/20/19	JPY	102.00	USD	120,342			(264,440	)
											(2,537,858	)
										$	(3,140,381	)

^(a)  Security is valued using significant unobservable inputs and is classified as Level 3 in the fair value hierarchy.

OTC Interest Rate Swaptions Written

Paid by the Fund

Received by the Fund

Counterparty

Expiration Date

Exercise Rate

Notional Amount (000)

Description

Rate

Frequency

Rate

Frequency

Value

Put

2-Year Interest Rate Swap, 03/25/22

3-month LIBOR, 2.09%

Quarterly

1.71

%

Semi-Annual

Deutsche Bank AG

03/23/20

1.71%

USD

234,990

$

(408,011

)

Centrally Cleared Credit Default Swaps — Buy Protection

Reference Obligation	Financing Rate Paid by the Fund		Payment     Frequency		Termination     Date		Notional Amount (000)		Value			Upfront Premium Paid (Received)			Unrealized Appreciation (Depreciation)
CDX.NA.IG.32.V1		1.00%		Quarterly		06/20/24		USD     71,835	$	(1,556,992	)	$	(1,613,293	)		$	56,301
ITRAXX.EUR.32.V1		1.00%		Quarterly		12/20/24		EUR   358,233		(9,218,917	)		(9,061,700	)			(157,217	)
CDX.NA.IG.33.V1		1.00%		Quarterly		12/20/24		USD   170,755		(3,446,785	)		(3,548,907	)			102,122
									$	(14,222,694	)	$	(14,223,900	)		$	1,206

Centrally Cleared Credit Default Swaps — Sell Protection

Reference Obligation

Financing Rate Received by the Fund

Payment     Frequency

Termination     Date

Credit   Rating(a)

Notional Amount (000)(b)

Value

Upfront Premium Paid (Received)

Unrealized Appreciation (Depreciation)

CDX.NA.HY.33.V1

5.00%

Quarterly

12/20/24

B+

USD

10,400

$

713,489

$

690,181

$

23,308

^(a)  Using the rating of the issuer or the underlying securities of the index, as applicable, provided by S&P Global Ratings.

^(b)  The maximum potential amount the Master Portfolio may pay should a negative credit event take place as defined under the terms of the agreement.

84 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Centrally Cleared Inflation Swaps

Paid by the Fund		Received by the Fund		Termination		Notional Amount					Upfront Premium Paid			Unrealized Appreciation
Reference	Frequency	Rate	Frequency	Date		(000)		Value			(Received)			(Depreciation)
0.81%	At Termination	Eurostat Eurozone HICP Ex Tobacco NSA (CPTFEMU)	At Termination		09/15/24		EUR  241,985	$	(186,431	)		$	3,512		$	(189,943	)
Eurostat Eurozone HICP Ex Tobacco NSA (CPTFEMU)	At Termination	0.99%	At Termination		09/15/29		EUR  241,985		364,116				6,168			357,948
								$	177,685			$	9,680		$	168,005

Centrally Cleared Interest Rate Swaps

Paid by the Fund		Received by the Fund		Effective	Termination		Notional Amount					Upfront Premium Paid			Unrealized Appreciation
Rate	Frequency	Rate	Frequency	Date	Date		(000)		Value			(Received)			(Depreciation)
28-day MXIBTIIE, 8.03%	Monthly	8.21%	Monthly	N/A		10/07/20	MXN	665,409		$  376,992			$	30		$	376,962
3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	1.77%	Semi-Annual	N/A		06/26/21	CAD	56,565		(104,229	)			383			(104,612	)
3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	1.76%	Semi-Annual	N/A		06/26/21	CAD	56,565		(116,931	)			399			(117,330	)
3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	1.82%	Semi-Annual	N/A		07/05/21	CAD	57,135		(56,805	)			647			(57,452	)
6.86%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	7/24/20(a)		07/23/21	MXN	136,786		(39,992	)			12			(40,004	)
6.90%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	7/27/20(a)		07/26/21	MXN	190,933		(59,540	)			17			(59,557	)
3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	1.79%	Semi-Annual	N/A		08/01/21	CAD	50,565		(67,015	)			347			(67,362	)
6.78%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	8/07/20(a)		08/06/21	MXN	604,159		(156,012	)			52			(156,064	)
3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	1.85%	Semi-Annual	N/A		09/11/21	CAD	104,440		(21,470	)			620			(22,090	)
6-month GBP LIBOR, 0.83%	Semi-Annual	0.75%	Semi-Annual	N/A		09/24/21	GBP	318,820		650,000				2,940			647,060
6-month GBP LIBOR, 0.83%	Semi-Annual	0.73%	Semi-Annual	N/A		09/26/21	GBP	320,060		486,971				3,212			483,759
2.58%	Semi-Annual	3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	N/A		12/03/21	CAD	15,645		(210,667	)			255			(210,922	)
6-month CIBOR, (0.30)%	Semi-Annual	0.12%	Annual	N/A		12/06/21	DKK	92,248		167,222				1,828			165,394

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 85

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Paid by the Fund		Received by the Fund		Effective	Termination		Notional Amount					Upfront Premium Paid				Unrealized Appreciation
Rate	Frequency	Rate	Frequency	Date	Date		(000)		Value			(Received)				(Depreciation)
6-month STIBOR, 0.02%	Quarterly	0.17%	Annual	N/A		12/06/21	SEK	128,311		$   90,077			$	1,418			$	88,659
3.01%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		12/07/21	USD	11,851		(450,444	)			(3,125	)			(447,319	)
6-month EURIBOR, (0.39)%	Semi-Annual	(0.35)%	Annual	N/A		07/03/22	EUR	10,000		47,579				83				47,496
7.23%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		07/18/22	MXN	148,112		(128,772	)			(237	)			(128,535	)
7.23%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		07/19/22	MXN	74,056		(64,986	)			(118	)			(64,868	)
7.22%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		07/20/22	MXN	28,487		(24,690	)			(46	)			(24,644	)
7.21%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		07/25/22	MXN	39,870		(34,497	)			9				(34,506	)
0.63%	Semi-Annual	6-month GBP LIBOR, 0.83%	Semi-Annual	N/A		08/01/22	GBP	6,000		(72	)			(1	)			(71	)
7.20%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		08/03/22	MXN	271,274		(227,064	)			(424	)			(226,640	)
28-day MXIBTIIE, 8.03%	Monthly	7.00%	Monthly	N/A		08/11/22	MXN	347,829		202,947				746				202,201
3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	1.58%	Semi-Annual	8/23/21(a)		08/23/22	CAD	214,000		(167,820	)			504				(168,324	)
7.11%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		10/14/22	MXN	146,271		(116,321	)			69				(116,390	)
7.11%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	N/A		10/14/22	MXN	110,975		(89,045	)			52				(89,097	)
2.62%	Semi-Annual	3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	N/A		12/03/23	CAD	9,604		(267,631	)			(816	)			(266,815	)
6-month EURIBOR, (0.39)%	Semi-Annual	0.28%	Annual	N/A		12/04/23	EUR	7,490		270,878				940				269,938
6-month CIBOR, (0.30)%	Semi-Annual	0.42%	Annual	N/A		12/06/23	DKK	55,726		299,488				4,026				295,462
6-month STIBOR, 0.02%	Quarterly	0.51%	Annual	N/A		12/06/23	SEK	77,818		222,648				2,263				220,385
3.00%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		12/07/23	USD	7,311		(498,401	)			(3,653	)			(494,748	)
28-day MXIBTIIE, 8.03%	Monthly	8.13%	Monthly	N/A		02/02/24	MXN	168,229		522,733				362				522,371
28-day MXIBTIIE, 8.03%	Monthly	8.14%	Monthly	N/A		02/05/24	MXN	120,900		378,807				118				378,689
1.30%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	1/06/20(a)		02/29/24	USD	88,052		585,139				(18,609	)			603,748

86 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Paid by the Fund		Received by the Fund		Effective     Date	Termination Date		Notional Amount (000)		Value			Upfront Premium Paid (Received)			Unrealized Appreciation (Depreciation)
Rate	Frequency	Rate	Frequency
1.56%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	1/06/20(a)		02/29/24	USD	44,026		$(157,494	)		$  390			$(157,884	)
1.77%	Annual	6-month NIBOR, 1.91%	Semi-Annual	N/A		06/05/24	NOK	60,000		(16,503	)		68			(16,571	)
28-day MXIBTIIE, 8.03%	Monthly	6.73%	Monthly	N/A		08/09/24	MXN	117,510		44,758			882			43,876
28-day MXIBTIIE, 8.03%	Monthly	6.67%	Monthly	N/A		08/12/24	USD	258,548		66,442			688			65,754
28-day MXIBTIIE, 8.03%	Monthly	6.72%	Monthly	N/A		08/13/24	EUR	222,465		79,262			574			78,688
28-day MXIBTIIE, 8.03%	Monthly	6.32%	Monthly	N/A		07/17/25	MXN	73,475		(48,761	)		324			(49,085	)
3-month LIBOR, 2.09%	Quarterly	2.13%	Semi-Annual	N/A		08/25/25	USD	2,360		82,671			21			82,650
2.27%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		09/11/25	USD	1,800		(78,043	)		23			(78,066	)
2.91%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		08/23/26	USD	3,692		(342,199	)		(46	)		(342,153	)
2.93%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		08/24/28	USD	8,170		(946,796	)		128			(946,924	)
3.16%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		10/03/28	USD	4,519		(656,800	)		71			(656,871	)
2.75%	Semi-Annual	3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	N/A		12/03/28	CAD	5,110		(341,499	)		(2,133	)		(339,366	)
6-month CIBOR, (0.30)%	Semi-Annual	1.03%	Annual	N/A		12/06/28	DKK	28,735		497,148			7,581			489,567
6-month STIBOR, 0.02%	Quarterly	1.16%	Annual	N/A		12/06/28	SEK	40,557		397,311			6,636			390,675
3.08%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		12/07/28	USD	3,916		(547,194	)		(2,139	)		(545,055	)
1.86%	Annual	6-month NIBOR, 1.91%	Semi-Annual	N/A		06/05/29	NOK	32,000		(54,202	)		63			(54,265	)
6-month CHF LIBOR, (0.72)%	Semi-Annual	(0.59)%	Annual	N/A		09/05/29	CHF	4,300		(82,187	)		74			(82,261	)
2.91%	Semi-Annual	3-month Canadian Bankers Acceptances, 1.97%	Semi-Annual	N/A		12/03/48	CAD	2,165		(385,248	)		(444	)		(384,804	)
6-month EURIBOR, (0.39)%	Semi-Annual	1.46%	Annual	N/A		12/04/48	EUR	1,518		623,766			92			623,674
1.73%	Semi-Annual	6-month GBP LIBOR, 0.83%	Semi-Annual	N/A		12/04/48	GBP	1,134		(383,871	)		1,687			(385,558	)
6-month CIBOR, (0.30)%	Semi-Annual	1.53%	Annual	N/A		12/06/48	DKK	11,141		654,630			694			653,936

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 87

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Paid by the Fund		Received by the Fund		Effective     Date	Termination Date		Notional Amount (000)		Value				Upfront Premium Paid (Received)				Unrealized Appreciation (Depreciation)
Rate	Frequency	Rate	Frequency
6-month STIBOR, 0.02%	Quarterly	1.68%	Annual	N/A		12/06/48	SEK	16,157		$	486,678			$	2,289			$	484,389
3.19%	Semi-Annual	3-month LIBOR, 2.09%	Quarterly	N/A		12/07/48	USD	1,695			(599,775	)			(1,494	)			(598,281	)
										$	(308,829	)		$	10,332			$	(319,161	)

^(a) Forward swap.

OTC Credit Default Swaps — Buy Protection

Reference Obligation	Financing Rate Paid by the Fund		Payment Frequency	Counterparty	Termination Date	Notional Amount (000)		Value				Upfront Premium Paid (Received)				Unrealized Appreciation (Depreciation)
Beazer Homes USA, Inc.		5.00%	Quarterly	Barclays Bank PLC	06/20/20	USD	2,050		$	(72,029	)		$	(61,684	)		$	(10,345	)
HCA, Inc.		5.00%	Quarterly	JPMorgan Chase Bank N.A.	06/20/20	USD	3,095			(112,633	)			(102,938	)			(9,695	)
HCA, Inc.		5.00%	Quarterly	JPMorgan Chase Bank N.A.	06/20/20	USD	930			(33,845	)			(31,073	)			(2,772	)
United Mexican States		1.00%	Quarterly	JPMorgan Chase Bank N.A.	06/20/20	USD	7,452			(38,910	)			9,451				(48,361	)
United Mexican States		1.00%	Quarterly	Bank of America N.A.	09/20/20	USD	7,452			(47,642	)			18,226				(65,868	)
Australia & New Zealand Banking Group Ltd.		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	USD	1,205			(13,892	)			(1,373	)			(12,519	)
Australia & New Zealand Banking Group Ltd.		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	USD	1,000			(11,531	)			(88	)			(11,443	)
Australia & New Zealand Banking Group Ltd.		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	USD	795			(9,169	)			(998	)			(8,171	)
Commonwealth Bank of Australia		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	USD	1,150			(13,380	)			(1,031	)			(12,349	)
Commonwealth Bank of Australia		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	USD	1,000			(11,634	)			(661	)			(10,973	)
Itochu Corp.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	32,023			(3,465	)			(462	)			(3,003	)
Itochu Corp.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	29,326			(3,173	)			(412	)			(2,761	)
Itochu Corp.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	29,326			(3,173	)			(389	)			(2,784	)
Itochu Corp.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	29,326			(3,173	)			(312	)			(2,861	)
Mitsubishi Corp.		1.00%	Quarterly	Barclays Bank PLC	12/20/20	JPY	47,573			(5,257	)			(1,547	)			(3,710	)
Mitsubishi Corp.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	29,326			(3,241	)			(811	)			(2,430	)
Mitsui & Co. Ltd.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	58,651			(6,460	)			(637	)			(5,823	)
Mitsui & Co. Ltd.		1.00%	Quarterly	Goldman Sachs International	12/20/20	JPY	29,326			(3,230	)			(239	)			(2,991	)
National Australia Bank Ltd.		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	USD	1,000			(11,671	)			(334	)			(11,337	)
Standard Chartered Bank		1.00%	Quarterly	BNP Paribas S.A.	12/20/20	EUR	810			(10,113	)			4,926				(15,039	)
Standard Chartered Bank		1.00%	Quarterly	BNP Paribas S.A.	12/20/20	EUR	460			(5,744	)			2,917				(8,661	)
Standard Chartered Bank		1.00%	Quarterly	Goldman Sachs International	12/20/20	EUR	610			(7,616	)			1,653				(9,269	)
Standard Chartered Bank		1.00%	Quarterly	Morgan Stanley & Co. International PLC	12/20/20	EUR	240			(2,996	)			1,553				(4,549	)
Sumitomo Corp.		1.00%	Quarterly	Barclays Bank PLC	12/20/20	JPY	24,938			(2,728	)			239				(2,967	)
Sumitomo Corp.		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/20	JPY	25,316			(2,770	)			421				(3,191	)
Westpac Banking Corp.		1.00%	Quarterly	Citibank N.A.	12/20/20	USD	1,000			(11,613	)			(777	)			(10,836	)
Frontier Communications Corp.		5.00%	Quarterly	Barclays Bank PLC	06/20/21	USD	1,661			861,340				373,545				487,795
Frontier Communications Corp.		5.00%	Quarterly	Barclays Bank PLC	06/20/21	USD	725			378,177				155,954				222,223
Transocean, Inc.		1.00%	Quarterly	Morgan Stanley & Co. International PLC	06/20/22	USD	2,172			247,951				190,997				56,954
DISH DBS Corp.		5.00%	Quarterly	Goldman Sachs International	12/20/23	USD	2,168			(149,783	)			94,394				(244,177	)
KB Home		5.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/23	USD	2,138			(347,239	)			(151,737	)			(195,502	)

88 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Reference Obligation	Financing Rate Paid by the Fund		Payment Frequency	Counterparty	Termination Date		Notional Amount (000)		Value				Upfront Premium Paid (Received)				Unrealized    Appreciation   (Depreciation)
Realogy Group LLC		5.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/23	��	USD	1,069		$	113,296			$	(8,869	)		$	122,165
RR Donnelley & Sons Co.		5.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/23		USD	1,070			(5,420	)			45,878				(51,298	)
Beazer Homes USA, Inc.		5.00%	Quarterly	Barclays Bank PLC	06/20/24		USD	1,199			(119,409	)			(75,667	)			(43,742	)
Beazer Homes USA, Inc.		5.00%	Quarterly	BNP Paribas S.A.	06/20/24		USD	1,103			(109,848	)			(66,325	)			(43,523	)
Beazer Homes USA, Inc.		5.00%	Quarterly	BNP Paribas S.A.	06/20/24		USD	1,000			(99,590	)			(55,723	)			(43,867	)
Tenet Healthcare Corp.		5.00%	Quarterly	Barclays Bank PLC	06/20/24		USD	1,000			(45,770	)			(11,121	)			(34,649	)
Tenet Healthcare Corp.		5.00%	Quarterly	Goldman Sachs International	06/20/24		USD	1,223			(55,970	)			(16,448	)			(39,522	)
Tenet Healthcare Corp.		5.00%	Quarterly	Goldman Sachs International	06/20/24		USD	1,175			(53,779	)			(40,119	)			(13,660	)
Tenet Healthcare Corp.		5.00%	Quarterly	Goldman Sachs International	06/20/24		USD	1,175			(53,779	)			(40,084	)			(13,695	)
Tenet Healthcare Corp.		5.00%	Quarterly	Goldman Sachs International	06/20/24		USD	1,150			(52,635	)			(39,231	)			(13,404	)
Tenet Healthcare Corp.		5.00%	Quarterly	JPMorgan Chase Bank N.A.	06/20/24		USD	500			(22,885	)			(6,511	)			(16,374	)
Broadcom, Inc.		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/24		USD	1,325			40,071				42,454				(2,383	)
CDX.EM.32.V1		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	8,090			423,410				394,342				29,068
Federative Republic of Brazil		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	39,966			710,454				693,733				16,721
Federative Republic of Brazil		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	7,570			134,567				131,393				3,174
Federative Republic of Brazil		1.00%	Quarterly	Goldman Sachs International	12/20/24		USD	25,912			460,631				491,204				(30,573	)
Federative Republic of Brazil		1.00%	Quarterly	Goldman Sachs International	12/20/24		USD	4,524			80,428				85,766				(5,338	)
Republic of Argentina		5.00%	Quarterly	Morgan Stanley & Co. International PLC	12/20/24		USD	2,714			1,630,265				1,557,804				72,461
Republic of Colombia		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	50,670			(175,283	)			(192,213	)			16,930
Republic of Colombia		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	2,313			(8,001	)			(8,774	)			773
Republic of Colombia		1.00%	Quarterly	Morgan Stanley & Co. International PLC	12/20/24		USD	27,910			(96,550	)			(110,942	)			14,392
Republic of Colombia		1.00%	Quarterly	Morgan Stanley & Co. International PLC	12/20/24		USD	1,280			(4,428	)			(5,088	)			660
Republic of South Africa		1.00%	Quarterly	Goldman Sachs International	12/20/24		USD	26,499			1,169,060				1,069,095				99,965
Republic of the Philippines		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	18,990			(493,855	)			(500,604	)			6,749
Republic of Turkey		1.00%	Quarterly	Goldman Sachs International	12/20/24		USD	11,575			1,338,776				1,502,210				(163,434	)
State of Qatar		1.00%	Quarterly	JPMorgan Chase Bank N.A.	12/20/24		USD	4,095			(95,682	)			(106,210	)			10,528
United Mexican States		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	36,742			282,164				289,835				(7,671	)
United Mexican States		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	21,450			164,726				135,845				28,881
United Mexican States		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	6,938			53,280				54,729				(1,449	)
United Mexican States		1.00%	Quarterly	Citibank N.A.	12/20/24		USD	4,060			31,179				25,712				5,467
CMBX.NA.9.AAA		0.50%	Annual	Credit Suisse International	09/17/58		USD	4,540			(58,280	)			52,725				(111,005	)
CMBX.NA.9.AAA		0.50%	Annual	Deutsche Bank AG	09/17/58		USD	3,620			(46,470	)			42,649				(89,119	)
CMBX.NA.9.AAA		0.50%	Annual	Morgan Stanley & Co. International PLC	09/17/58		USD	5,570			(71,501	)			70,977				(142,478	)
CMBX.NA.9.AAA		0.50%	Annual	Morgan Stanley & Co. International PLC	09/17/58		USD	3,050			(39,153	)			35,421				(74,574	)
CMBX.NA.9.AAA		0.50%	Annual	Morgan Stanley & Co. International PLC	09/17/58		USD	2,530			(32,477	)			29,382				(61,859	)
CMBX.NA.9.BBB-		3.00%	Monthly	Citigroup Global Markets, Inc.	09/17/58		USD	2,080			56,119				72,578				(16,459	)
CMBX.NA.9.BBB-		3.00%	Monthly	Morgan Stanley & Co. International PLC	09/17/58		USD	204			5,504				11,655				(6,151	)
CMBX.NA.6.AAA		0.50%	Annual	Deutsche Bank AG	05/11/63		USD	5,519			(47,741	)			(1,744	)			(45,997	)
CMBX.NA.6.AAA		0.50%	Annual	Deutsche Bank AG	05/11/63		USD	2,271			(19,647	)			428				(20,075	)
CMBX.NA.6.BBB-		3.00%	Annual	J.P. Morgan Securities LLC	05/11/63		USD	850			71,502				81,247				(9,745	)
										$	5,496,637			$	6,128,162			$	(631,525	)

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 89

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

OTC Credit Default Swaps — Sell Protection

Reference Obligation	Financing Rate Received by the Fund			Payment Frequency		Counterparty	Termination Date	Credit Rating(a)	Notional Amount (000)(b)		Value				Upfront Premium Paid (Received)			Unrealized   Appreciation  (Depreciation)
United Mexican States		1.00	%		Quarterly	Bank of America N.A.	06/20/20	BBB+	USD	7,452		$	38,910		$	(10,955	)		$	49,865
People’s Republic of China		1.00	%		Quarterly	Barclays Bank PLC	09/20/20	A+	USD	1,000			9,190			(1,577	)			10,767
People’s Republic of China		1.00	%		Quarterly	Goldman Sachs International	09/20/20	A+	USD	1,000			9,191			(1,667	)			10,858
United Mexican States		1.00	%		Quarterly	JPMorgan Chase Bank N.A.	09/20/20	BBB+	USD	7,452			47,642			(15,878	)			63,520
ITRAXX.ASIA.XJ.IG.24.V1		1.00	%		Quarterly	Goldman Sachs International	12/20/20	A	USD	1,825			21,810			(12,460	)			34,270
Beazer Homes USA, Inc.		5.00	%		Quarterly	Barclays Bank PLC	06/20/23	B-	USD	2,050			220,241			123,625				96,616
Beazer Homes USA, Inc.		5.00	%		Quarterly	Goldman Sachs International	06/20/23	B-	USD	1,036			111,300			34,907				76,393
Beazer Homes USA, Inc.		5.00	%		Quarterly	Goldman Sachs International	06/20/23	B-	USD	622			66,780			21,533				45,247
Broadcom, Inc.		1.00	%		Quarterly	Citibank N.A.	06/20/24	BBB-	USD	14,931			(833,454	)		(1,080,000	)			246,546
Republic of Turkey		1.00	%		Quarterly	Goldman Sachs International	12/20/24	B+	USD	2,894			(334,694	)		(375,552	)			40,858
CMBX.NA.7.AAA		0.50	%		Monthly	Morgan Stanley & Co. International PLC	01/17/47	AAA	USD	4,977			59,079			(147,254	)			206,333
CMBX.NA.3.AM		0.50	%		Monthly	Credit Suisse International	12/13/49	Not Rated	USD	11			(38	)		(910	)			872
CMBX.NA.3.AM		0.50	%		Monthly	Goldman Sachs International	12/13/49	Not Rated	USD	28			(98	)		(2,325	)			2,227
CMBX.NA.3.AM		0.50	%		Monthly	JPMorgan Chase Bank N.A.	12/13/49	Not Rated	USD	60			(211	)		(4,754	)			4,543
CMBX.NA.9.BBB-		3.00	%		Monthly	Deutsche Bank AG	09/17/58	Not Rated	USD	906			(24,444	)		(107,029	)			82,585
CMBX.NA.9.BBB-		3.00	%		Monthly	J.P. Morgan Securities LLC	09/17/58	Not Rated	USD	438			(11,817	)		(38,169	)			26,352
CMBX.NA.9.BBB-		3.00	%		Monthly	Morgan Stanley & Co. International PLC	09/17/58	Not Rated	USD	1,060			(28,599	)		(52,886	)			24,287
CMBX.NA.9.BBB-		3.00	%		Quarterly	Morgan Stanley & Co. International PLC	09/17/58	Not Rated	USD	486			(13,113	)		(29,151	)			16,038
CMBX.NA.10.A		2.00	%		Monthly	Deutsche Bank AG	11/17/59	A-	USD	3,340			13,102			(143,125	)			156,227
CMBX.NA.10.A		2.00	%		Monthly	Deutsche Bank AG	11/17/59	A-	USD	1,670			6,551			(72,766	)			79,317
CMBX.NA.10.BBB-		3.00	%		Annual	J.P. Morgan Securities LLC	11/17/59	BBB-	USD	60			(1,960	)		(5,087	)			3,127
CMBX.NA.6.BBB-		3.00	%		Annual	Credit Suisse International	05/11/63	BB+	USD	850			(71,503	)		(65,794	)			(5,709	)
												$	(716,135	)	$	(1,987,274	)		$	1,271,139

^(a)  Using the rating of the issuer or the underlying securities of the index, as applicable, provided by S&P Global Ratings.

^(b)  The maximum potential amount the Master Portfolio may pay should a negative credit event take place as defined under the terms of the agreement.

OTC Interest Rate Swaps

Paid by the Fund		Received by the Fund			Termination	Notional Amount					Upfront Premium Paid			Unrealized   Appreciation
Rate	Frequency	Rate	Frequency	Counterparty	Date	(000)		Value			(Received)			(Depreciation)
3.27%	Quarterly	3-month LIBOR, 2.09%	Semi-Annual	Deutsche Bank AG	05/16/21	USD	9,510	$	(330,395	)		$	—		$	(330,395	)
1-day BZDIOVER, 0.02%	At Termination	8.27%	At Termination	JPMorgan Chase Bank N.A.	01/02/23	BRL	62,487		1,302,718				—			1,302,718
1-day BZDIOVER, 0.02%	At Termination	6.35%	At Termination	JPMorgan Chase Bank N.A.	01/02/23	BRL	110,569		309,397				—			309,397
5.73%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	Bank of America N.A.	01/03/25	MXN	23,376		45,056				262			44,794

90 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Paid by the Fund		Received by the Fund			Termination		Notional Amount						Upfront Premium Paid				Unrealized   Appreciation
Rate	Frequency	Rate	Frequency	Counterparty	Date		(000)			Value			(Received)				(Depreciation)
28-day MXIBTIIE, 8.03%	Monthly	6.33%	Monthly	Citibank N.A.		06/09/25		MXN	14,869	$	(9,664	)		$	(63	)		$	(9,601	)
28-day MXIBTIIE, 8.03%	Monthly	6.33%	Monthly	Citibank N.A.		07/17/25		MXN	36,610		(23,838	)			(122	)			(23,716	)
28-day MXIBTIIE, 8.03%	Monthly	6.32%	Monthly	Goldman Sachs International		08/06/25		MXN	109,616		(75,986	)			(356	)			(75,630	)
6.31%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	Bank of America N.A.		08/11/25		MXN	36,783		26,168				154				26,014
6.31%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	Bank of America N.A.		08/11/25		MXN	36,783		26,168				154				26,014
6.31%	Monthly	28-day MXIBTIIE, 8.03%	Monthly	Deutsche Bank AG		08/11/25		MXN	136,536		98,105				571				97,534
28-day MXIBTIIE, 8.03%	Monthly	6.27%	Monthly	Bank of America N.A.		12/05/25		MXN	4,348		(3,828	)			(39	)			(3,789	)
										$	1,363,901			$	561			$	1,363,340

OTC Total Return Swaps

Paid by the Fund

Received by the Fund

Termination

Notional Amount

Upfront Premium Paid

Unrealized   Appreciation

Rate

Frequency

Rate

Frequency

Counterparty

Date

(000)

Value

(Received)

(Depreciation)

SPDR Barclays Capital High Yield Bond ETF

Quarterly

3-month LIBOR minus 0.60%, 2.09%

Quarterly

Citibank N.A.

10/10/19

USD

23,013

$

(167,001

)

$

—

$

(167,001

)

Canadian Natural Resources Ltd.

Quarterly

3-month LIBOR minus 0.45%, 2.09%

Quarterly

BNP Paribas S.A.

11/27/19

USD

528

(84,028

)

—

(84,028

)

SPDR S&P Oil & Gas Exploration & Production ETF

Monthly

1-month LIBOR minus 0.47%, 2.02%

Monthly

Merrill Lynch International

03/17/20

USD

1,086

103,890

—

103,890

Occidental Petroleum Corp.

Quarterly

3-month LIBOR, 2.09%

Quarterly

BNP Paribas S.A.

05/15/20

USD

2,432

(65,145

)

—

(65,145

)

Sprint Corp.

Quarterly

3-month LIBOR, 2.09%

Quarterly

Citibank N.A.

06/11/20

USD

735

91,420

—

91,420

Sprint Corp.

Quarterly

3-month LIBOR, 2.09%

Quarterly

Citibank N.A.

06/11/20

USD

735

91,420

—

91,420

Intelsat SA

Quarterly

3-month LIBOR minus 0.52%, 2.09%

Quarterly

Credit Suisse International

06/11/20

USD

2,175

(64,225

)

—

(64,225

)

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 91

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Paid by the Fund

Received by the Fund

Termination

Notional Amount

Upfront Premium Paid

Unrealized    Appreciation

Rate

Frequency

Rate

Frequency

Counterparty

Date

(000)

Value

(Received)

(Depreciation)

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

102

$

16,133

$—

$

16,133

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

40

6,273

—

6,273

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

29

4,546

—

4,546

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

25

3,947

—

3,947

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

22

3,409

—

3,409

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

17

2,630

—

2,630

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

15

2,371

—

2,371

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

12

1,818

—

1,818

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

10

1,500

—

1,500

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

9

1,463

—

1,463

Quorum Health Corp.

Quarterly

3-month LIBOR minus 1.25%, 2.09%

Quarterly

JPMorgan Chase Bank N.A.

06/11/20

USD

9

1,364

—

1,364

Consumer Staples Select Sector SPD

Monthly

1-month LIBOR plus 0.05%, 2.02%

Monthly

Merrill Lynch International

07/11/20

USD

4,607

(43,317

)

—

(43,317

)

iShares Transportation Average ETF

Monthly

1-month LIBOR minus 0.90%, 2.02%

Monthly

Merrill Lynch International

07/11/20

USD

4,467

173,533

—

173,533

92 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Paid by the Fund		Received by the Fund			Termination Date	Notional Amount (000)						Upfront Premium Paid (Received)			Unrealized Appreciation (Depreciation)
Rate	Frequency	Rate	Frequency	Counterparty					Value
SPDR S&P Retail ETF	Monthly	1-month LIBOR minus 0.95%, 2.02%	Monthly	BNP Paribas S.A.	07/13/20		USD	2,334	$	(15,087	)		$	—	$	(15,087	)
SPDR S&P Retail ETF	Monthly	1-month LIBOR minus 0.95%, 2.02%	Monthly	Citibank N.A.	07/13/20		USD	2,291		57,895				—		57,895
SPDR S&P Retail ETF	Monthly	1-month LIBOR minus 0.95%, 2.02%	Monthly	Citibank N.A.	07/13/20		USD	2,122		48,973				—		48,973
Sprint Corp.	Quarterly	3-month LIBOR minus 0.08%, 2.09%	Quarterly	BNP Paribas S.A.	07/17/20		USD	2,011		221,709				—		221,709
Charter Communications, Inc.	Quarterly	3-month LIBOR minus 0.25%, 2.09%	Quarterly	BNP Paribas S.A.	08/05/20		USD	599		(42,233	)			—		(42,233	)
SPDR S&P Oil & Gas Exploration & Production ETF	Quarterly	3-month LIBOR minus 0.63%, 2.09%	Quarterly	BNP Paribas S.A.	08/05/20		USD	464		(10,013	)			—		(10,013	)
Charter Communications, Inc.	Quarterly	3-month LIBOR minus 0.10%, 2.09%	Quarterly	BNP Paribas S.A.	08/26/20		USD	1,192		(37,351	)			—		(37,351	)
3-month LIBOR, 2.09%	Quarterly	Goldman Sachs Systematic Skew U.S. Series 10 Excess Return Strategy	Quarterly	Goldman Sachs International	09/09/20		USD	3,129		31				—		31
Tidewater, Inc.	Quarterly	3-month LIBOR minus 0.30%, 2.09%	Quarterly	BNP Paribas S.A.	09/29/20		USD	229		(1,092	)			—		(1,092	)
									$	304,833			$	—	$	304,833

Balances Reported in the Statement of Assets and Liabilities for Centrally Cleared Swaps, OTC Swaps and Options Written

	Swap Premiums Paid		Swap Premiums Received			Unrealized         Appreciation		Unrealized     Depreciation			Value
Centrally Cleared Swaps(a)		$   743,478		$(14,257,185	)		$7,755,012		$(7,881,654	)	$	—
OTC Swaps		7,952,544		(3,811,095	)		5,112,550		(2,804,763	)		—
Options Written		N/A		N/A			2,205,182		(999,398	)		(8,861,759	)

^(a)  Includes cumulative appreciation (depreciation) on centrally cleared swaps, as reported in the Schedule of Investments. Only current day’s variation margin is reported within the Statement of Assets and Liabilities and is net of any previously paid (received) swap premium amounts.

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 93

Schedule of Investments  (continued) September 30, 2019 Master Total Return 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:

Assets — Derivative Financial Instruments		Commodity Contracts			Credit Contracts		Equity Contracts		Foreign Currency Exchange Contracts		Interest Rate Contracts		Other Contracts		Total
Futures contracts	Unrealized appreciation on futures contracts(a)		$	—	$	—	$	390,898	$	—	$	9,262,431	$	—	$	9,653,329
Forward foreign currency exchange contracts	Unrealized appreciation on forward foreign currency exchange contracts			—		—		—		29,652,971		—		—		29,652,971
Options purchased	Investments at value — unaffiliated(b)			—		—		6,683,369		5,644,305		3,287,958		—		15,615,632
Swaps — centrally cleared	Unrealized appreciation on centrally cleared swaps(a)			—		181,731		—		—		7,215,333		357,948		7,755,012
Swaps — OTC	Unrealized appreciation on OTC swaps; Swap premiums paid			—		10,423,157		834,325		—		1,807,612		—		13,065,094
			$	—	$	10,604,888	$	7,908,592	$	35,297,276	$	21,573,334	$	357,948	$	75,742,038
Liabilities — Derivative Financial Instruments
Futures contracts	Unrealized depreciation on futures contracts(a)		$	—	$	—	$	30,440	$	—	$	13,340,574	$	—	$	13,371,014
Forward foreign currency exchange contracts	Unrealized depreciation on forward foreign currency exchange contracts			—		—		—		16,382,929		—		—		16,382,929
Options written	Options written at value			—		—		4,956,757		3,140,381		764,621		—		8,861,759
Swaps — centrally cleared	Unrealized depreciation on centrally cleared swaps(a)			—		157,217		—		—		7,534,494		189,943		7,881,654
Swaps — OTC	Unrealized depreciation on OTC swaps; Swap premiums received			—		5,642,655		529,492		—		443,711		—		6,615,858
			$	—	$	5,799,872	$	5,516,689	$	19,523,310	$	22,083,400	$	189,943	$	53,113,214

^(a)  Net cumulative unrealized appreciation (depreciation) on futures contracts and centrally cleared swaps, 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).

^(b)  Includes options purchased at value as reported in the Schedule of Investments.

For the year ended September 30, 2019, the effect of derivative financial instruments in the Consolidated Statement of Operations was as follows:

Net Realized Gain (Loss) from:	Commodity Contracts			Credit Contracts			Equity Contracts			Foreign Currency Exchange Contracts			Interest Rate Contracts			Other Contracts			Total
Futures contracts	$	(13,435	)	$	—		$	(15,624,025	)	$	—		$	131,047,709		$	—		$	115,410,249
Forward foreign currency exchange contracts		—			—			—			18,103,812			—			—			18,103,812
Options purchased(a)		—			(213,857	)		11,349,142			(35,791,931	)		(15,275,432	)		—			(39,932,078	)
Options written		—			—			(1,677,735	)		22,556,927			5,096,725			—			25,975,917
Swaps		—			(13,791,003	)		3,807,328			(170,389	)		(1,778,809	)		(6,437,849	)		(18,370,722	)
	$	(13,435	)	$	(14,004,860	)	$	(2,145,290	)	$	4,698,419		$	119,090,193		$	(6,437,849	)	$	101,187,178

^(a) Options purchased are included in net realized gain (loss) from investments.

Net Change in Unrealized Appreciation (Depreciation) on:	Commodity Contracts		Credit Contracts		Equity Contracts			Foreign Currency Exchange Contracts			Interest Rate Contracts		Other Contracts		Total
Futures contracts	$	71,559	$	—	$	(460,988	)	$	—		$	48,650,853	$	—	$	48,261,424
Forward foreign currency exchange contracts		—		—		—			(4,613,806	)		—		—		(4,613,806	)
Options purchased(a)		—		—		1,119,425			7,664,240			3,504,513		—		12,288,178
Options written		—		—		(181,484	)		(3,685,244	)		963,823		—		(2,902,905	)
Swaps		—		4,703,786		545,221			—			380,907		94,720		5,724,634
	$	71,559	$	4,703,786	$	1,022,174		$	(634,810	)	$	53,500,096	$	94,720	$	58,757,525

^(a)  Options purchased are included in net change in unrealized appreciation (depreciation) on investments.

94 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

Average Quarterly Balances of Outstanding Derivative Financial Instruments

Futures contracts:
Average notional value of contracts — long	$	5,098,237,720
Average notional value of contracts — short		1,550,592,710
Forward foreign currency exchange contracts:
Average amounts purchased — in USD		1,143,009,037
Average amounts sold — in USD		679,104,380
Options:
Average value of option contracts purchased		10,883,282
Average value of option contracts written		7,178,086
Average notional value of swaption contracts purchased		509,514,000
Average notional value of swaption contracts written		422,852,000
Credit default swaps:
Average notional value — buy protection		605,073,537
Average notional value — sell protection		85,023,660
Interest rate swaps:
Average notional value — pays fixed rate		1,709,631,182
Average notional value — receives fixed rate		2,062,552,133
Currency swaps:
Average notional value — pays fixed rate		480,444
Average notional value — receives fixed rate		2,250
Inflation swaps:
Average notional value — pays fixed rate		209,012,540
Average notional value — receives fixed rate		201,947,894
Total return swaps:
Average notional value		27,829,192

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

Derivative Financial Instruments – Offsetting as of Period End

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

	Assets			Liabilities
Derivative Financial Instruments:
Futures contracts	$	1,273,895		$	1,203,730
Forward foreign currency exchange contracts		29,652,971			16,382,929
Options		15,615,632	(a)		8,861,759
Swaps — Centrally cleared		1,976,016			—
Swaps — OTC(b)		13,065,094			6,615,858
Total derivative assets and liabilities in the Statement of Assets and Liabilities	$	61,583,608		$	33,064,276
Derivatives not subject to a Master Netting Agreement or similar agreement (“MNA”)		(10,038,093	)		(6,517,097	)
Total derivative assets and liabilities subject to an MNA	$	51,545,515		$	26,547,179

^(a)  Includes interest rate caps purchased at value and options purchased at value which are included in Investments at value — unaffiliated in the Statement of Assets and Liabilities and reported in the Schedule of Investments.

^(b)  Includes unrealized appreciation (depreciation) on OTC swaps and swap premiums paid/received in the Statement of Assets and Liabilities.

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 95

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

The following tables present the Master Portfolio’s derivative assets and liabilities by counterparty net of amounts for offset under an MNA and net of the related collateral received and pledged by the Master Portfolio:

Counterparty		Derivative Assets Subject to an MNA by Counterparty		Derivatives Available for Offset(a)		Non-cash Collateral Received				Cash Collateral Received			Net Amount of Derivative Assets(b)(c)
Bank of America N.A	$	11,441,427	$	(455,408	)		$	—	$	(2,340,000	)	$	8,646,019
Barclays Bank PLC		1,508,560		(324,901	)			—		(1,183,659	)		—
BNP Paribas S.A		4,440,493		(2,684,808	)			—		(1,130,000	)		625,685
Citibank N.A		3,290,718		(3,290,718	)			—		—			—
Citigroup Global Markets, Inc.		72,578		(16,459	)			—		—			56,119
Credit Suisse International		224,446		(224,446	)			—		—			—
Deutsche Bank AG		15,655,571		(1,843,450	)			—		—			13,812,121
Goldman Sachs International		3,803,554		(1,521,459	)			—		(2,210,000	)		72,095
HSBC Bank PLC		3,238,269		(1,189,599	)			—		—			2,048,670
J.P. Morgan Securities LLC		110,726		(53,001	)			—		—			57,725
JPMorgan Chase Bank N.A		3,509,686		(3,509,686	)			—		—			—
Merrill Lynch International		277,423		(43,317	)			—		—			234,106
Morgan Stanley & Co.
International PLC		2,776,833		(1,336,760	)			—		(910,000	)		530,073
NatWest Markets PLC		555,450		(555,450	)			—		—			—
Royal Bank of Canada		215,222		—				—		—			215,222
Standard Chartered Bank		218,212		(218,212	)			—		—			—
UBS AG		206,347		(206,347	)			—		—			—
	$	51,545,515	$	(17,474,021	)		$	—	$	(7,773,659	)	$	26,297,835
Counterparty		Derivative Liabilities Subject to an MNA by Counterparty		Derivatives Available for Offset(a)		Non-cash Collateral Pledged				Cash Collateral Pledged(d)			Net Amount of Derivative Liabilities(c)(e)
Bank of America N.A	$	455,408	$	(455,408	)		$	—	$	—		$	—
Barclays Bank PLC		324,901		(324,901	)			—		—			—
BNP Paribas S.A		2,684,808		(2,684,808	)			—		—			—
Citibank N.A		3,320,820		(3,290,718	)			—		—			30,102
Citigroup Global Markets, Inc.		16,459		(16,459	)			—		—			—
Credit Suisse International		247,643		(224,446	)			—		(23,197	)		—
Deutsche Bank AG		1,843,450		(1,843,450	)			—		—			—
Goldman Sachs International		1,521,459		(1,521,459	)			—		—			—
HSBC Bank PLC		1,189,599		(1,189,599	)			—		—			—
J.P. Morgan Securities LLC		53,001		(53,001	)			—		—			—
JPMorgan Chase Bank N.A		11,150,349		(3,509,686	)			—		—			7,640,663
Merrill Lynch International		43,317		(43,317	)			—		—			—
Morgan Stanley & Co.
International PLC		1,336,760		(1,336,760	)			—		—			—
NatWest Markets PLC		1,358,929		(555,450	)			—		(380,000	)		423,479
Standard Chartered Bank		326,875		(218,212	)			—		—			108,663
TD Securities, Inc.		1,548		—				—		—			1,548
UBS AG		671,853		(206,347	)			—		(465,506	)		—
	$	26,547,179	$	(17,474,021	)		$	—	$	(868,703	)	$	8,204,455

^(a)  The amount of derivatives available for offset is limited to the amount of derivative assets and/or liabilities that are subject to an MNA.

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

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

^(d)  Excess of collateral pledged to the individual counterparty is not shown for financial reporting purposes.

^(e)  Net amount represents the net amount payable due to the counterparty in the event of default. Net amount may be offset further by the options written receivable/payable on the Statement of Assets and Liabilities.

96 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return 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 Master Portfolio’s policy regarding valuation of investments and derivative financial instruments, refer to the Notes to Consolidated 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:
Asset-Backed Securities	$	—	$	1,493,560,326		$	119,808,152	$	1,613,368,478
Common Stocks(a)		34,680,415		—			—		34,680,415
Corporate Bonds(a)		—		5,802,613,510			24,565,099		5,827,178,609
Floating Rate Loan Interests(a)		—		185,447,160			143,255,372		328,702,532
Foreign Agency Obligations		—		167,100,265			—		167,100,265
Foreign Government Obligations		—		502,007,979			—		502,007,979
Investment Companies		44,007,375		—			—		44,007,375
Non-Agency Mortgage-Backed Securities		—		784,222,589			36,178,812		820,401,401
Preferred Securities(a)		—		135,147,670			—		135,147,670
Taxable Municipal Bonds		—		757,533,379			—		757,533,379
U.S. Government Sponsored Agency Securities		—		12,456,935,035			—		12,456,935,035
U.S. Treasury Obligations		—		1,305,385,954			—		1,305,385,954
Warrants(a)		76,151		—			—		76,151
Short-Term Securities:
Money Market Funds		205,577,418		—			—		205,577,418
Options Purchased:
Equity contracts		6,683,369		—			—		6,683,369
Foreign currency exchange contracts		—		5,644,304			1		5,644,305
Interest rate contracts		104,813		3,183,145			—		3,287,958
Liabilities:
TBA Sale Commitments		—		(5,502,455,395	)		—		(5,502,455,395	)
Unfunded floating rate loan interests(b)		—		(14,242	)		—		(14,242	)
Subtotal	$	291,129,541	$	18,096,311,679		$	323,807,436	$	18,711,248,656
Investments Valued at NAV(c)									1,616,850
Total Investments								$	18,712,865,506

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

^(b)  Unfunded floating rate loan interests are valued at the unrealized appreciation (depreciation) on the commitment.

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

	Level 1			Level 2			Level 3			Total
Derivative Financial Instruments(a)
Assets:
Credit contracts	$	—		$	2,653,485		$	—		$	2,653,485
Equity contracts		390,898			834,325			—			1,225,223
Foreign currency exchange contracts		—			29,652,971			—			29,652,971
Interest rate contracts		9,262,431			9,021,804			—			18,284,235
Other contracts		—			357,948			—			357,948
Liabilities:
Credit contracts		—			(1,989,357	)		—			(1,989,357	)
Equity contracts		(4,987,197	)		(529,492	)		—			(5,516,689	)
Foreign currency exchange contracts		—			(19,523,309	)		(1	)		(19,523,310	)
Interest rate contracts		(13,697,184	)		(8,385,636	)		—			(22,082,820	)
Other contracts		—			(189,943	)		—			(189,943	)
	$	(9,031,052	)	$	11,902,796		$	(1	)	$	2,871,743

^(a)  Derivative financial instruments are swaps, financial futures contracts, forward foreign currency exchange contracts and options written. Swaps, financial futures contracts and forward foreign currency exchange contracts are valued at the unrealized appreciation (depreciation) on the instrument and options written are shown at value.

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 97

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

A reconciliation of Level 3 investments is presented when the Master Portfolio had a significant amount of Level 3 investments at the beginning and/or end of the period in relation to net assets. The following table is a reconciliation of Level 3 investments for which significant unobservable inputs were used in determining fair value:

	Asset-Backed Securities			Common Stocks			Corporate Bonds			Floating Rate Loan Interests			Non-Agency Mortgage- Backed Securities
Assets:
Opening Balance, as of September 30, 2018	$	61,899,804		$	218,040		$	111,000,003		$	127,990,875		$	60,105,857
Transfers into Level 3		33,675,433			—			—			52,047,625			1,880,091
Transfers out of Level 3		(19,008,110	)		—			—			(18,753,250	)		(21,361,234	)
Accrued discounts/premiums		31,684			—			—			4,219			5,656
Net realized gain (loss)		115,894			(342,007	)		—			168,626			(4,056,821	)
Net change in unrealized appreciation (depreciation)(a)(b)		551,069			324,431			190,998			(2,367,483	)		2,451,113
Purchases		83,267,373			—			24,505,000			110,809,083			27,119,786
Sales		(40,724,995	)		(200,464	)		(111,130,902	)		(126,644,323	)		(29,965,636	)
Closing Balance, as of September 30, 2019	$	119,808,152		$	—		$	24,565,099		$	143,255,372		$	36,178,812
Net change in unrealized appreciation (depreciation) on investments still held at September 30, 2019(b)	$	262,928		$	—		$	190,998		$	58,638		$	(2,126,311	)

	Preferred Securities			U.S. Government Sponsored Agency Securities				Options Purchased				Total
Assets:
Opening Balance, as of September 30, 2018	$	240,721			$	840,797			$	39		$	362,296,136
Transfers into Level 3		—				—				—			87,603,149
Transfers out of Level 3		—				—				—			(59,122,594	)
Accrued discounts/premiums		—				—				—			41,559
Net realized gain (loss)		(867,195	)			(93,030	)			—			(5,074,533	)
Net change in unrealized appreciation (depreciation)(a)(b)		847,791				73,932				(11,262	)		2,060,589
Purchases		—				—				11,224			245,712,466
Sales		(221,317	)			(821,699	)			—			(309,709,336	)
Closing Balance, as of September 30, 2019	$	—			$	—			$	1		$	323,807,436
Net change in unrealized appreciation (depreciation) on investments still held at September 30, 2019(b	$	—			$	—			$	(11,222	)	$	(1,624,969	)

^(a)  Any difference between net change in unrealized appreciation (depreciation) and net change in unrealized appreciation (depreciation) on investments still held at September 30, 2019, is generally due to investments no longer held or categorized as Level 3 at period end.

^(b)  Included in the related net change in unrealized appreciation (depreciation) in the Consolidated Statement of Operations.

98 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Schedule of Investments  (continued) September 30, 2019 Master Total Return Portfolio

The following table is a reconciliation of Level 3 derivative financial instruments for which significant unobservable inputs were used in determining fair value:

	Foreign Currency Exchange Contracts
		Assets		Liabilities
Opening Balance, as of September 30, 2018		$	—	$	(39	)
Transfers into Level 3			—		—
Transfers out of Level 3			—		—
Accrued discounts/premiums			—		—
Net realized gain (loss)			—		—
Net change in unrealized appreciation (depreciation)(b)			—		38
Purchases			—		—
Issues			—		—
Sales			—		—
Settlements			—		—
Closing Balance, as of September 30, 2019		$	—	$	(1	)
Net change in unrealized appreciation (depreciation) on derivative financial instruments still held at September 30, 2019(a)(b)		$	—	$	(1	)

^(a)  Included in the related net change in unrealized appreciation (depreciation) in the Consolidated Statement of Operations.

^(b)  Any difference between net change in unrealized appreciation (depreciation) and net change in unrealized appreciation (depreciation) on investments still held at September 30, 2019 is generally due to investments no longer held or categorized as Level 3 at period end.

The Master Portfolio’s investments that are categorized as Level 3 were valued utilizing third party pricing information without adjustment. Such valuations are based on unobservable inputs. A significant change in third party information could result in a significantly lower or higher value of such Level 3 investments.

See notes to consolidated financial statements.

MASTER PORTFOLIO SCHEDULE OF INVESTMENTS 99

Statement of Assets and Liabilities

September 30, 2019

	Master Total Return Portfolio
ASSETS
Investments at value — unaffiliated (including securities loaned at value of $1,554,525) (cost — $23,619,008,727)	$	24,002,497,759
Investments at value — affiliated (cost — $212,966,166)		212,837,384
Cash		19,663,411
Cash pledged:
Collateral — OTC derivatives		3,170,000
Collateral — TBA commitments		249,106
Futures contracts		48,597,010
Centrally cleared swaps		29,937,630
Foreign currency at value (cost — $40,623,142)		40,387,099
Receivables:
Investments sold		494,970,185
Options written		464,894
Securities lending income — affiliated		1,827
Swaps		1,921,970
TBA sale commitments		5,500,310,481
Contributions from investors		9,125,031
Dividends — affiliated		602,478
Dividends — unaffiliated		32,333
Interest — unaffiliated		109,230,827
Variation margin on futures contracts		1,273,895
Variation margin on centrally cleared swaps		1,976,016
Swap premiums paid		7,952,544
Unrealized appreciation on:
Forward foreign currency exchange contracts		29,652,971
OTC swaps		5,112,550
Prepaid expenses		106,737
Total assets		30,520,074,138
LIABILITIES
Cash received:
Collateral — OTC derivatives		9,980,000
Collateral — TBA commitments		7,332,000
Cash collateral on securities loaned at value		1,616,850
Options written at value (premiums received — $10,067,543)		8,861,759
TBA sale commitments at value (proceeds — $5,500,310,481)		5,502,455,395
Payables:
Investments purchased		9,248,347,496
Swaps		1,385,238
Directors’ fees		14,707
Investment advisory fees		656,815
Options written		85,409
Other accrued expenses		773,802
Other affiliates		80,642
Variation margin on futures contracts		1,203,730
Withdrawals to investors		1,435,862
Swap premiums received		3,811,095
Unrealized depreciation on:
Forward foreign currency exchange contracts		16,382,929
OTC swaps		2,804,763
Unfunded floating rate loan interests		14,242
Total liabilities		14,807,242,734
NET ASSETS	$	15,712,831,404
NET ASSETS CONSIST OF
Investors’ capital	$	15,319,585,431
Net unrealized appreciation (depreciation)		393,245,973
NET ASSETS	$	15,712,831,404

See notes to consolidated financial statements.

100 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Consolidated Statement of Operations  

Year Ended September 30, 2019

	Master Total Return Portfolio
INVESTMENT INCOME
Interest — unaffiliated	$	501,973,352
Dividends — affiliated		16,792,002
Dividends — unaffiliated		353,101
Securities lending income — affiliated — net		91,969
Foreign taxes withheld		(337,086	)
Total investment income		518,873,338
EXPENSES
Investment advisory		7,412,484
Custodian		702,640
Accounting services		675,538
Professional		189,802
Directors		141,098
Printing		17,960
Miscellaneous		654,750
Total expenses		9,794,272
Less fees waived and/or reimbursed by the Manager		(458,818	)
Total expenses after fees waived and/or reimbursed		9,335,454
Net investment income		509,537,884
REALIZED AND UNREALIZED GAIN (LOSS)
Net realized gain (loss) from:
Investments — unaffiliated (net of $128,753 foreign capital gain tax)		95,633,029
Investments — affiliated		(4,084,069	)
Foreign currency transactions		59,868
Forward foreign currency exchange contracts		18,103,812
Futures contracts		115,410,249
Options written		25,975,917
Swaps		(18,370,722	)
		232,728,084
Net change in unrealized appreciation (depreciation) on:
Investments — unaffiliated		612,024,557
Investments — affiliated		(732,274	)
Foreign currency translations		(197,299	)
Forward foreign currency exchange contracts		(4,613,806	)
Futures contracts		48,261,424
Options written		(2,902,905	)
Swaps		5,724,634
Unfunded floating rate loan interests		(14,242	)
		657,550,089
Net realized and unrealized gain		890,278,173
NET INCREASE IN NET ASSETS RESULTING FROM OPERATIONS	$	1,399,816,057

See notes to consolidated financial statements.

MASTER PORTFOLIO CONSOLIDATED FINANCIAL STATEMENTS 101

Consolidated Statements of Changes in Net Assets

	Master Total Return Portfolio
	Year Ended September 30,
	2019			2018
INCREASE (DECREASE) IN NET ASSETS
OPERATIONS
Net investment income	$	509,537,884		$	464,469,339
Net realized gain (loss)		232,728,084			(212,466,813	)
Net change in unrealized appreciation (depreciation)		657,550,089			(394,697,234	)
Net increase (decrease) in net assets resulting from operations		1,399,816,057			(142,694,708	)
CAPITAL TRANSACTIONS
Proceeds from contributions.		5,976,173,038			5,934,095,058
Value of withdrawals		(4,727,004,752	)		(4,328,662,619	)
Net increase in net assets derived from capital transactions.		1,249,168,286			1,605,432,439
NET ASSETS
Total increase in net assets		2,648,984,343			1,462,737,731
Beginning of year		13,063,847,061			11,601,109,330
End of year	$	15,712,831,404		$	13,063,847,061

See notes to consolidated financial statements.

102 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Consolidated Financial Highlights  

	Master Total Return Portfolio
	Year Ended September 30,
	2019			2018			2017			2016			2015
Total Return
Total return		10.60	%		(1.19	)%(a)		1.90	%		5.75	%		3.13	%
Ratios to Average Net Assets(b)
Total expenses		0.07	%		0.34	%		0.32	%		0.21	%		0.14	%
Total expenses after fees waived		0.07	%		0.34	%		0.32	%		0.21	%		0.14	%
Total expenses after fees waived and excluding interest expense		0.07	%		0.07	%		0.08	%		0.08	%		0.09	%
Net investment income		3.70	%		3.67	%		3.30	%		3.03	%		3.07	%
Supplemental Data
Net assets, end of year (000)	$	15,712,831		$	13,063,847		$	11,601,109		$	9,309,960		$	7,418,036
Portfolio turnover rate(c)		574	%		734	%		806	%		841	%		1,015	%

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

^(b)  Excludes expenses incurred indirectly as a result of investments in underlying funds as follows:

		Year Ended September 30,
		2019			2018			2017			2016			2015
	Investments in underlying funds		0.01	%		0.01	%		0.01	%		0.01	%		—
(c)  Includes mortgage dollar roll transactions. Additional information regarding portfolio turnover rate is as follows:
		Year Ended September 30,
		2019			2018			2017			2016			2015
	Portfolio turnover rate (excluding mortgage dollar roll transactions)		241	%		350	%		540	%		598	%		725	%

See notes to consolidated financial statements.

MASTER PORTFOLIO CONSOLIDATED FINANCIAL HIGHLIGHTS 103

Notes to Consolidated Financial Statements Master Total Return Portfolio

1. ORGANIZATION

Master Total Return Portfolio (the “Master Portfolio”), a series of Master Bond LLC, is registered under the Investment Company Act of 1940, as amended (the “1940 Act”), as an open-end management investment company. The Master Portfolio is classified as diversified. The Master Bond LLC is organized as a Delaware limited liability company. The Limited Liability Company Agreement of the Master Bond LLC permits the Board of Directors of the Master Bond LLC (the “Board”) to issue nontransferable interests in the Master Bond LLC, subject to certain limitations.

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 non-index fixed-income mutual funds and all BlackRock-advised closed-end funds referred to as the BlackRock Fixed-Income Complex.

Basis of Consolidation:The accompanying consolidated financial statements include the accounts of BlackRock Cayman Master Total Return Portfolio I, Ltd. (the “Subsidiary”), which was a wholly-owned subsidiary of the Master Portfolio and primarily invested in commodity-related instruments. Effective November 30, 2018, the Master Portfolio no longer invests in the Subsidiary. The Subsidiary enabled the Master Portfolio to hold these commodity-related instruments while allowing its investors to satisfy regulated investment company tax requirements. Prior to November 30, 2018, the Master Portfolio invested up to 25% of its total assets in the Subsidiary. Intercompany accounts and transactions, if any, have been eliminated. The Subsidiary was subject to the same investment policies and restrictions that apply to the Master Portfolio, except that the Subsidiary could invest without limitation in commodity-related instruments.

2. SIGNIFICANT ACCOUNTING POLICIES

The consolidated 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 consolidated financial statements, disclosure of contingent assets and liabilities at the date of the consolidated 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 the ex-dividend date. Dividends from foreign securities where the ex-dividend date may have passed are subsequently recorded when the Master Portfolio is informed of the ex-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. Income, expenses and realized and unrealized gains and losses are allocated daily to each class based on its relative net assets.

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 Consolidated 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., mortgage dollar rolls, to-be-announced (“TBA”) sale commitments, futures contracts, forward foreign currency exchange contracts, options written, swaps and structured options) 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 or borrowings 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.

Deferred Compensation Plan:Under the Deferred Compensation Plan (the “Plan”) approved by the Master Portfolio’s Board effective January 1, 2019, the directors who are not “interested persons” of the Master Bond LLC, as defined in the 1940 Act (“Independent Directors”), may defer a portion of their annual complex-wide compensation. Deferred amounts earn an approximate return as though equivalent dollar amounts had been invested in common shares of certain funds in the BlackRock Fixed-Income Complex selected by the Independent Directors. This has the same economic effect for the Independent Directors as if the Independent Directors had invested the deferred amounts directly in certain funds in the BlackRock Fixed-Income Complex.

The Plan is not funded and obligations thereunder represent general unsecured claims against the general assets of the Master Portfolio, as applicable. Deferred compensation liabilities are included in the Directors’ fees payable in the Statement of Assets and Liabilities and will remain as a liability of the Master Portfolio until such amounts are distributed in accordance with the Plan.

Recent Accounting Standards:In March 2017, the Financial Accounting Standards Board issued Accounting Standards Update “Premium Amortization of Purchased Callable Debt Securities” which amends the amortization period for certain purchased callable debt securities. Under the new guidance, the premium amortization of purchased callable debt securities that have explicit, non-contingent call features and are callable at fixed prices will be amortized to the earliest call date. The guidance will be applied on a modified retrospective basis and is effective for fiscal years, and their interim periods, beginning after December 15, 2018. Management continues to evaluate the impact of this guidance on the Master Portfolio.

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Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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.

The Master Portfolio has an arrangement with its custodian whereby credits are earned on uninvested cash balances, which could be used to reduce custody fees and/or overdraft charges. The Master Portfolio may incur charges on certain uninvested cash balances and overdrafts, subject to certain conditions.

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) (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 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.

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.

• 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 the Master Portfolio 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.

• 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 exchange-traded equity securities and foreign exchange-traded and over-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.

• 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 in open-end U.S. mutual funds are valued at net asset value (“NAV”) each business day.

• The Master Portfolio values its investment in SL Liquidity Series, LLC, Money Market Series (the “Money Market Series”) at fair value, which is ordinarily based upon its pro rata ownership in the underlying fund’s net assets. The Money Market Series seeks current income consistent with maintaining liquidity and preserving capital. Although the Money Market Series is not registered under the 1940 Act, its investments may follow the parameters of investments by a money market fund that is subject to Rule 2a-7 under the 1940 Act.

• 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.

• Exchange-traded options are valued at the mean between the last bid and ask prices at the close of the options market in which the options trade. An exchange-traded option for which there is no mean price is valued at the last bid (long positions) or ask (short positions) price. If no bid or ask price is available, the prior day’s price will be used, unless it is determined that the prior day’s price no longer reflects the fair value of the option. OTC options and options on swaps (“swaptions”) are valued by an independent pricing service using a mathematical model, which incorporates a number of market data factors, such as the trades and prices of the underlying instruments.

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Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

• Swap agreements are valued utilizing quotes received daily by the Master Portfolio’s 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.

• 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 an arm’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 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.

As of September 30, 2019, certain investments of the Master Portfolio were valued using NAV (or its equivalent) as no quoted market value is available and therefore have been excluded from the fair value hierarchy.

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Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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 by non-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.

Collateralized Debt Obligations:Collateralized debt obligations (“CDOs”), including collateralized bond obligations (“CBOs”) and collateralized loan obligations (“CLOs”), are types of asset-backed securities. A CDO is an entity that is backed by a diversified pool of debt securities (CBOs) or syndicated bank loans (CLOs). The cash flows of the CDO can be split into multiple segments, called “tranches,” which will vary in risk profile and yield. The riskiest segment is the subordinated or “equity” tranche. This tranche bears the greatest risk of defaults from the underlying assets in the CDO and serves to protect the other, more senior, tranches from default in all but the most severe circumstances. Since it is shielded from defaults by the more junior tranches, a “senior” tranche will typically have higher credit ratings and lower yields than their underlying securities, and often receive investment grade ratings from one or more of the nationally recognized rating agencies. Despite the protection from the more junior tranches, senior tranches can experience substantial losses due to actual defaults, increased sensitivity to future defaults and the disappearance of one or more protecting tranches as a result of changes in the credit profile of the underlying pool of assets.

Inflation-Indexed Bonds:Inflation-indexed bonds (other than municipal inflation-indexed and certain corporate inflation-indexed bonds) are fixed-income securities whose principal value is periodically adjusted according to the rate of inflation. If the index measuring inflation rises or falls, the principal value of inflation-indexed bonds (other than municipal inflation-indexed and certain corporate inflation-indexed bonds) will be adjusted upward or downward, and consequently the interest payable on these securities (calculated with respect to a larger or smaller principal amount) will be increased or reduced, respectively. Any upward or downward adjustment in the principal amount of an inflation-indexed bond will be included as interest income in the Consolidated Statement of Operations, even though investors do not receive their principal until maturity. Repayment of the original bond principal upon maturity (as adjusted for inflation) is guaranteed in the case of U.S. Treasury inflation-indexed bonds. For bonds that do not provide a similar guarantee, the adjusted principal value of the bond repaid at maturity may be less than the original principal. With regard to municipal inflation-indexed bonds and certain corporate inflation-indexed bonds, the inflation adjustment is typically reflected in the semi-annual coupon payment. As a result, the principal value of municipal inflation-indexed bonds and such corporate inflation-indexed bonds does not adjust according to the rate of inflation.

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.

Stripped Mortgage-Backed Securities: Stripped mortgage-backed securities are typically issued by the U.S. Government, its agencies and instrumentalities. Stripped mortgage-backed securities are usually structured with two classes that receive different proportions of the interest (IOs) and principal (POs) distributions on a pool of Mortgage Assets. Stripped mortgage-backed securities may be privately issued.

Zero-Coupon Bonds:Zero-coupon bonds are normally issued at a significant discount from face value and do not provide for periodic interest payments. These bonds may experience greater volatility in market value than other debt obligations of similar maturity which provide for regular interest payments.

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

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Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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.

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.

Floating Rate Loan Interests:Floating rate loan interests are typically issued to companies (the “borrower”) by banks, other financial institutions, or privately and publicly offered corporations (the “lender”). Floating rate loan interests are generally non-investment grade, often involve borrowers whose financial condition is troubled or uncertain and companies that are highly leveraged or in bankruptcy proceedings. In addition, transactions in floating rate loan interests may settle on a delayed basis, which may result in proceeds from the sale not being readily available for the Master Portfolio to make additional investments or meet its redemption obligations. Floating rate loan interests may include fully funded term loans or revolving lines of credit. Floating rate loan interests are typically senior in the corporate capital structure of the borrower. Floating rate loan interests generally pay interest at rates that are periodically determined by reference to a base lending rate plus a premium. Since the rates reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the NAV of the Master Portfolio to the extent that it invests in floating rate loan interests. The base lending rates are generally the lending rate offered by one or more European banks, such as the London Interbank Offered Rate (“LIBOR”), the prime rate offered by one or more U.S. banks or the certificate of deposit rate. Floating rate loan interests may involve foreign borrowers, and investments may be denominated in foreign currencies. These investments are treated as investments in debt securities for purposes of the Master Portfolio’s investment policies.

When the Master Portfolio purchases a floating rate loan interest, it may receive a facility fee and when it sells a floating rate loan interest, it may pay a facility fee. On an ongoing basis, the Master Portfolio may receive a commitment fee based on the undrawn portion of the underlying line of credit amount of a floating rate loan interest. Facility and commitment fees are typically amortized to income over the term of the loan or term of the commitment, respectively. Consent and amendment fees are recorded to income as earned. Prepayment penalty fees, which may be received by the Master Portfolio upon the prepayment of a floating rate loan interest by a borrower, are recorded as realized gains. The Master Portfolio may invest in multiple series or tranches of a loan. A different series or tranche may have varying terms and carry different associated risks.

Floating rate loan interests are usually freely callable at the borrower’s option. The Master Portfolio may invest in such loans in the form of participations in loans (“Participations”) or assignments (“Assignments”) of all or a portion of loans from third parties. Participations typically will result in the Master Portfolio having a contractual relationship only with the lender, not with the borrower. The Master Portfolio has the right to receive payments of principal, interest and any fees to which it is entitled only from the lender selling the Participation and only upon receipt by the lender of the payments from the borrower. In connection with purchasing Participations, the Master Portfolio generally will have no right to enforce compliance by the borrower with the terms of the loan agreement, nor any rights of offset against the borrower. The Master Portfolio may not benefit directly from any collateral supporting the loan in which it has purchased the Participation. As a result, the Master Portfolio assumes the credit risk of both the borrower and the lender that is selling the Participation. The Master Portfolio’s investment in loan participation interests involves the risk of insolvency of the financial intermediaries who are parties to the transactions. In the event of the insolvency of the lender selling the Participation, the Master Portfolio may be treated as a general creditor of the lender and may not benefit from any offset between the lender and the borrower. Assignments typically result in the Master Portfolio having a direct contractual relationship with the borrower, and the Master Portfolio may enforce compliance by the borrower with the terms of the loan agreement.

In connection with floating rate loan interests, the Master Portfolio may also enter into unfunded floating rate loan interests (“commitments”). In connection with these commitments, the Master Portfolio earns a commitment fee, typically set as a percentage of the commitment amount. Such fee income, which is included in interest income in the Consolidated Statement of Operations, is recognized ratably over the commitment period. Unfunded floating rate loan interests are marked-to-market daily, and any unrealized appreciation (depreciation) is included in the Statement of Assets and Liabilities and Consolidated Statement of Operations. As of period end, the Master Portfolio had the following unfunded floating rate loan interests:

Borrower	Par		Commitment Amount		Value		Unrealized Appreciation (Depreciation)
Aligned Energy Data Centers (SLC) Propco LLC, Term Loan		$1,698,364		$1,697,957		$1,688,119		$(9,838	)
BRE Park Avenue Tower Owner LLC, Term Loan		992,382		992,382		992,382		—
BSREP II Houston Office 1HC Owner LLC, Mezzanine A Loan		3,411,250		3,411,250		3,411,250		—
CSC Holdings LLC (FKA CSC Holdings Inc. (Cablevision)), Delayed Draw Term Loan		4,548,913		4,548,913		4,548,913		—
Facebook Burlingame, Term Loan		6,872,160		6,876,564		6,872,160		(4,404	)

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.

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Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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 the mark-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 in 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 counterparty non-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 realize 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 investment companies 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 Investment Management, LLC (“BIM”), 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 the non-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 or re-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 or re-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
J.P. Morgan Securities LLC		$	1,554,525		$	(1,554,525	)		$	—

^(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 BIM. BIM’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.

MASTER PORTFOLIO NOTESTO CONSOLIDATED FINANCIAL STATEMENTS 109

Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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 Consolidated 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.

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 Master Portfolio are denominated and in some cases, may be used to obtain exposure to a particular market.

The contract is marked-to-market daily and the change in market value is recorded as unrealized appreciation (depreciation) in the Statement of Assets and Liabilities. When a contract is closed, a realized gain or loss is recorded in the Consolidated Statement 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 Statement 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 Statement of Assets and Liabilities.

Options:The Master Portfolio purchases and writes call and put options to increase or decrease its exposure to the risks of underlying instruments, including equity risk, interest rate risk and/or commodity price risk and/or, in the case of options written, to generate gains from options premiums.

A call option gives the purchaser (holder) of the option the right (but not the obligation) to buy, and obligates the seller (writer) to sell (when the option is exercised) the underlying instrument at the exercise or strike price at any time or at a specified time during the option period. A put option gives the holder the right to sell and obligates the writer to buy the underlying instrument at the exercise or strike price at any time or at a specified time during the option period.

Premiums paid on options purchased and premiums received on options written, as well as the daily fluctuation in market value, are included in investments at value — unaffiliated and options written at value, respectively, in the Statement of Assets and Liabilities. When an instrument is purchased or sold through the exercise of an option, the premium is offset against the cost or proceeds of the underlying instrument. When an option expires, a realized gain or loss is recorded in the Consolidated Statement of Operations to the extent of the premiums received or paid. When an option is closed or sold, a gain or loss is recorded in the Consolidated Statement of Operations to the extent the cost of the closing transaction exceeds the premiums received or paid. When the Master Portfolio writes a call option, such option is typically “covered,” meaning that it holds the underlying instrument subject to being called by the option counterparty. When the Master Portfolio writes a put option, such option is covered by cash in an amount sufficient to cover the obligation. These amounts, which are considered restricted, are included in cash pledged as collateral for options written in the Statement of Assets and Liabilities.

• Swaptions — The Master Portfolio purchases and writes swaptions primarily to preserve a return or spread on a particular investment or portion of the Master Portfolio’s holdings, as a duration management technique or to protect against an increase in the price of securities it anticipates purchasing at a later date. The purchaser and writer of a swaption is buying or granting the right to enter into a previously agreed upon interest rate or credit default swap agreement (interest rate risk and/or credit risk) at any time before the expiration of the option.

• Interest rate caps and floors — Interest rate caps and floors are entered into to gain or reduce exposure to interest rates (interest rate risk and/or other risk). Caps are agreements whereby one party agrees to make payments to the other, in return for a premium, to the extent that interest rate indexes exceed a specified rate, or “cap.” Floors are agreements whereby one party agrees to make payments to the other, in return for a premium, to the extent that interest rate indexes fall below a specified rate, or “floor.” The maximum potential amount of future payments that the Master Portfolio would be required to make under an interest rate cap would be the notional amount times the percentage increase in interest rates determined by the difference between the interest rate index current value and the value at the time the cap was entered into.

• Foreign currency options — The Master Portfolio purchases and writes foreign currency options, foreign currency futures and options on foreign currency futures to gain or reduce exposure to foreign currencies (foreign currency exchange rate risk). Foreign currency options give the purchaser the right to buy from or sell to the writer a foreign currency at any time before the expiration of the option.

• Barrier options — The Master Portfolio may purchase and write a variety of options with non-standard payout structures or other features (“barrier options”) that are generally traded OTC.

110 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

The Master Portfolio may invest in various types of barrier options, including down-and-out options, down-and-in options, double no-touch options, one-touch options, up-and-out options and up-and-in options. Down-and-out options expire worthless to the purchaser if the price of the underlying instrument falls below a specific barrier price level prior to the expiration date. Down-and-in options expire worthless to the purchaser unless the price of the underlying instrument falls below a specific barrier price level prior to the expiration date. Double no-touch options provide the purchaser an agreed-upon payout if the price of the underlying instrument does not reach or surpass predetermined barrier price levels prior to the option’s expiration date. One-touch options provide the purchaser an agreed-upon payout if the price of the underlying instrument reaches or surpasses predetermined barrier price levels prior to the expiration date. Up-and-out options expire worthless to the purchaser if the price of the underlying instrument increases beyond a predetermined barrier price level prior to the expiration date. Up-and-in options can only be exercised when the price of the underlying instrument increases beyond a predetermined barrier price level.

• Structured options — The Master Portfolio invests in structured options to increase or decrease its exposure to an underlying index or group of securities (equity risk).

These options may consist of single or multiple OTC options which are priced as a single instrument. They may only be exercised at the expiration date, but may be transferred/sold prior to the expiration date. The value of a structured option may either increase or decrease with the underlying index or group of securities, depending on the combination of options used. Structured options are issued in units whereby each unit represents a structure based on the specific index with an initial reference strike price. One type of structure involves the combination of selling a put while buying a call on a specific index. This option would rise in value as the underlying index increases and fall in value as the underlying index decreases. Alternatively, another structure involves the sale of a call and the purchase of a put. This option structure would rise in value as the underlying index decreases and fall in value as the underlying index increases. Upon the exercise of the structured option, the Master Portfolio will receive a payment from, or be required to remit a payment to, the counterparty depending on the value of the underlying index at exercise.

In purchasing and writing options, the Master Portfolio bears the risk of an unfavorable change in the value of the underlying instrument or the risk that it may not be able to enter into a closing transaction due to an illiquid market. Exercise of a written option could result in the Master Portfolio purchasing or selling a security when it otherwise would not, or at a price different from the current market value.

Swaps:Swap contracts are entered into to manage exposure to issuers, markets and securities. Such contracts are agreements between the Master Portfolio and a counterparty to make periodic net payments on a specified notional amount or a net payment upon termination. Swap agreements are privately negotiated in the OTC market and may be entered into as a bilateral contract (“OTC swaps”) or centrally cleared (“centrally cleared swaps”).

For OTC swaps, any upfront premiums paid and any upfront fees received are shown as swap premiums paid and swap premiums received, respectively, in the Statement of Assets and Liabilities and amortized over the term of the contract. The daily fluctuation in market value is recorded as unrealized appreciation (depreciation) on OTC Swaps in the Statement of Assets and Liabilities. Payments received or paid are recorded in the Consolidated Statement of Operations as realized gains or losses, respectively. When an OTC swap is terminated, a realized gain or loss is recorded in the Consolidated Statement of Operations equal to the difference between the proceeds from (or cost of) the closing transaction and the Master Portfolio’s basis in the contract, if any. Generally, the basis of the contract is the premium received or paid.

In a centrally cleared swap, immediately following execution of the swap contract, the swap contract is novated to a central counterparty (the “CCP”) and the Master Portfolio’s counterparty on the swap agreement becomes the CCP. The Master Portfolio is required to interface with the CCP through the broker. Upon entering into a centrally cleared swap, 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 the size and risk profile of the particular swap. Securities deposited as initial margin are designated in the Schedule of Investments and cash deposited is shown as cash pledged for centrally cleared swaps in the Statement of Assets and Liabilities. Amounts pledged, which are considered restricted cash, are included in cash pledged for centrally cleared swaps 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 shown as variation margin receivable (or payable) on centrally cleared swaps in the Statement of Assets and Liabilities. Payments received from (paid to) the counterparty, including at termination, are recorded as realized gains (losses) in the Consolidated Statement of Operations.

• Credit default swaps — Credit default swaps are entered into to manage exposure to the market or certain sectors of the market, to reduce risk exposure to defaults of corporate and/or sovereign issuers or to create exposure to corporate and/or sovereign issuers to which a fund is not otherwise exposed (credit risk).

The Master Portfolio may either buy or sell (write) credit default swaps on single-name issuers (corporate or sovereign), a combination or basket of single-name issuers or traded indexes. Credit default swaps are agreements in which the protection buyer pays fixed periodic payments to the seller in consideration for a promise from the protection seller to make a specific payment should a negative credit event take place with respect to the referenced entity (e.g., bankruptcy, failure to pay, obligation acceleration, repudiation, moratorium or restructuring). As a buyer, if an underlying credit event occurs, the Master Portfolio will either (i) receive from the seller an amount equal to the notional amount of the swap and deliver the referenced security or underlying securities comprising the index, or (ii) receive a net settlement of cash equal to the notional amount of the swap less the recovery value of the security or underlying securities comprising the index. As a seller (writer), if an underlying credit event occurs, the Master Portfolio will either pay the buyer an amount equal to the notional amount of the swap and take delivery of the referenced security or underlying securities comprising the index or pay a net settlement of cash equal to the notional amount of the swap less the recovery value of the security or underlying securities comprising the index.

• Total return swaps — Total return swaps are entered into to obtain exposure to a security or market without owning such security or investing directly in such market or to exchange the risk/return of one security or market (e.g., fixed-income) with another security or market (e.g., equity or commodity prices) (equity risk, commodity price risk and/or interest rate risk).

Total return swaps are agreements in which there is an exchange of cash flows whereby one party commits to make payments based on the total return (distributions plus capital gains/losses) of an underlying instrument, or basket of underlying instruments, in exchange for fixed or floating rate interest payments. If the total return of the instruments or index underlying the transaction exceeds or falls short of the offsetting fixed or floating interest rate obligation, the Master Portfolio receives payment from or makes a payment to the counterparty.

MASTER PORTFOLIO NOTESTO CONSOLIDATED FINANCIAL STATEMENTS 111

Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

Certain total return swaps are designed to function as a portfolio of direct investments in long and short equity positions. This means that the Master Portfolio has the ability to trade in and out of these long and short positions within the swap and will receive the economic benefits and risks equivalent to direct investment in these positions, subject to certain adjustments due to events related to the counterparty. Benefits and risks include capital appreciation (depreciation), corporate actions and dividends received and paid, all of which are reflected in the swap’s market value. The market value also includes interest charges and credits (“financing fees”) related to the notional values of the long and short positions and cash balances within the swap. These interest charges and credits are based on a specified benchmark rate plus or minus a specified spread determined based upon the country and/or currency of the positions in the Master Portfolio.

Positions within the swap and financing fees are reset periodically. During a reset, any unrealized appreciation (depreciation) on positions and accrued financing fees become available for cash settlement between the Master Portfolio and the counterparty. The amounts that are available for cash settlement are recorded as realized gains or losses in the Consolidated Statement of Operations. Cash settlement in and out of the swap may occur at a reset date or any other date, at the discretion of the Master Portfolio and the counterparty, over the life of the agreement. Certain swaps have no stated expiration and can be terminated by either party at any time.

• Correlation swaps — Correlation swaps are entered into to gain or mitigate exposure to the underlying reference securities.

Correlation swaps involve two parties agreeing to exchange cash flows based on the measured correlation of two specified underlying securities. At inception, the strike correlation rate is generally chosen such that the fair value of the swap is zero. At the maturity date, a net cash flow is exchanged where the payoff amount is based on the difference between the realized price correlation of the underlying securities and the strike correlation rate. As a receiver (or payor) of the realized price correlation rate, a fund would receive (or owe) the payoff amount when the realized price correlation rate of the underlying securities is greater than the strike correlation rate and would owe (or receive) the payoff amount when the realized price correlation rate of the underlying securities is less than the strike correlation rate. This type of agreement is essentially a forward contract on the future realized price correlation of the underlying securities.

• Interest rate swaps — Interest rate swaps are entered into to gain or reduce exposure to interest rates or to manage duration, the yield curve or interest rate (interest rate risk).

Interest rate swaps are agreements in which one party pays a stream of interest payments, either fixed or floating, in exchange for another party’s stream of interest payments, either fixed or floating, on the same notional amount for a specified period of time. In more complex interest rate swaps, the notional principal amount may decline (or amortize) over time.

• Currency swaps — Currency swaps are entered into to gain or reduce exposure to foreign currencies (foreign currency exchange rate risk).

Currency swaps are interest rate swaps in which one party pays a stream of interest payments, either fixed or floating, in exchange for another party’s stream of interest payments, either fixed or floating, based on the notional amounts of two different currencies. The notional amounts are typically determined based on the spot exchange rates at the inception of the trade. Currency swaps may also involve an exchange of notional amounts at the start, during and/or at expiration of the contract, either at the current spot rate or another specified rate.

• Forward swaps — The Master Portfolio enters into forward interest rate swaps and forward total return swaps. In a forward swap, the Master Portfolio and the counterparty agree to make periodic net payments beginning on a specified date or a net payment at termination.

• Inflation swaps — Inflation swaps are entered into to gain or reduce exposure to inflation (inflation risk). In an inflation swap, one party makes fixed interest payments on a notional principal amount in exchange for another party’s variable payments based on an inflation index, such as the Consumer Price Index.

Swap transactions involve, to varying degrees, elements of interest rate, credit and market risk in excess of the amounts recognized in the Statement of Assets and Liabilities. Such risks involve the possibility that there will be no liquid market for these agreements, that the counterparty to the agreements may default on its obligation to perform or disagree as to the meaning of the contractual terms in the agreements, and that there may be unfavorable changes in interest rates and/or market values associated with these transactions.

Master Netting Arrangements:In order to define its contractual rights and to secure rights that will help it mitigate its counterparty risk, the Master Portfolio may enter into an International Swaps and Derivatives Association, Inc. Master Agreement (“ISDA Master Agreement”) or similar agreement with its counterparties. An ISDA Master Agreement is a bilateral agreement between the 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, the 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 the mark-to-market amount for each transaction under such agreement and comparing that amount to the value of any collateral currently pledged by the Master Portfolio and the counterparty.

Cash collateral that has been pledged to cover obligations of the Master Portfolio and cash collateral received from the counterparty, if any, is reported separately in the Statement of Assets and Liabilities as cash pledged as collateral and cash received as collateral, respectively. Non-cash collateral pledged by the Master Portfolio, if any, is noted in the Schedule 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 Master Portfolio. Any additional required collateral is delivered to/pledged by the Master Portfolio on the next business day. Typically, the counterparty is not permitted to sell, re-pledge or use cash and non-cash collateral it receives. The Master Portfolio generally agrees not to use non-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 Master Portfolio from its counterparties are not fully collateralized, it bears the risk of loss from counterparty non-performance. Likewise, to the extent the Master Portfolio has delivered collateral to a counterparty and stands ready to perform under the terms of its agreement with such counterparty, it bears 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.

112 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

For financial reporting purposes, the Master Portfolio does not offset derivative assets and derivative liabilities that are subject to netting arrangements, if any, in the Statement of Assets and Liabilities.

6. INVESTMENT ADVISORY AGREEMENT AND OTHER TRANSACTIONS WITH AFFILIATES

Investment Advisory:The Master Bond LLC, 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, Inc. (“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 the following percentages of the average daily value of the Master Portfolio’s net assets:

Average Daily Net Assets	Investment Advisory Fee
First $250 Million		0.16	%
$250 Million — $ 500 Million		0.12
$500 Million — $ 750 Million		0.08
Greater than $750 Million		0.05

The Manager provided investment management and other services to the Subsidiary. The Manager did not receive separate compensation from the Subsidiary for providing investment management or administrative services. However, the Master Portfolio paid the Manager based on the Master Portfolio’s net assets, which included the assets of the Subsidiary. Effective November 30, 2018, the Master Portfolio no longer invests in the Subsidiary.

With respect to the Master Portfolio, the Manager entered into separate sub-advisory agreements with BlackRock International Limited (“BIL”) and BlackRock (Singapore) Limited (“BRS”), each an affiliate of the Manager. The Manager pays BIL and BRS for services they provide, for that portion of the Master Portfolio for which BIL and BRS, as applicable, act as sub-adviser, a monthly fee that is equal to a percentage of the investment advisory fees paid by the Master Portfolio to the Manager.

Expense Waivers and Reimbursements: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 Consolidated Statement of Operations. For the year ended September 30, 2019, the amount waived was $438,811.

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 January 31, 2020. The contractual agreement may be terminated upon 90 days’ notice by a majority of the Independent Directors, 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 Consolidated Statement of Operations. For the year ended September 30, 2019, the Manager waived $20,007 in investment advisory fees pursuant to this arrangement.

For the year ended September 30, 2019, the Master Bond LLC reimbursed the Manager $165,833 for certain accounting services, which is included in accounting services in the Consolidated Statement of Operations.

Securities Lending:The U.S. Securities and Exchange Commission (“SEC”) has issued an exemptive order which permits BIM, an affiliate of the Manager, to serve as securities lending agent for the Master Portfolio, subject to applicable conditions. As securities lending agent, BIM bears all operational costs directly related to securities lending. The Master Portfolio is responsible for expenses in connection with the investment of cash collateral received for securities on loan (the “collateral investment expenses”). The cash collateral is invested in a private investment company managed by the Manager or its affiliates. However, BIM has agreed to cap the collateral investment expenses of the private investment company to an annual rate of 0.04%. The investment adviser to the private investment company will not charge any advisory fees with respect to shares purchased by the Master Portfolio. The private investment company in which the cash collateral has been invested may, under certain circumstances, impose a liquidity fee of up to 2% of the value withdrawn or temporarily restrict withdrawals for up to 10 business days during a 90 day period, in the event that the private investment company’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 expenses. The Master Portfolio retains a portion of securities lending income and remits a remaining portion to BIM 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 expenses), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment expenses.

In addition, commencing the business day following the date that the aggregate securities lending income earned across the BlackRock Fixed-Income 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 expenses), and this amount retained can never be less than 70% of the total of securities lending income plus the collateral investment expenses.

Prior to January 1, 2019, the Master Portfolio retained 80% of securities lending income (which excluded collateral investment expenses) and the amount retained could never be less than 70% of the total of securities lending income plus the collateral investment expenses. In addition, commencing the business day following the date that the aggregate securities lending income earned across a complex of open-end funds referred to as the Equity-Bond Complex in a calendar year exceeded a specified threshold, the Master Portfolio would retain for the remainder of that calendar year 85% of securities lending income (which excluded collateral investment expenses), and the amount retained could never be less than 70% of the total of securities lending income plus the collateral investment expenses.

MASTER PORTFOLIO NOTESTO CONSOLIDATED FINANCIAL STATEMENTS 113

Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

The share of securities lending income earned by the Master Portfolio is shown as securities lending income — affiliated — net in the Consolidated Statement of Operations. For the year ended September 30, 2019, the Master Portfolio paid BIM $18,093 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 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 September 30, 2019, the Master Portfolio did not participate in the Interfund Lending Program.

Directors and Officers:Certain directors and/or officers of the Master Bond LLC 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 directors. For the year ended September 30, 2019, the purchase and sale transactions and any net realized gains (losses) with an affiliated fund in compliance with Rule 17a-7 under the 1940 Act were as follows:

Purchases	Sales	Net Realized Loss
$20,085,350	$24,870,481	$(277,012)

7. PURCHASES AND SALES

For the year ended September 30, 2019, purchases and sales of investments, including paydowns and mortgage dollar rolls and excluding short-term securities, were as follows:

	Purchases		Sales
Non-U.S. Government Securities	$	83,999,976,973	$	79,869,346,182
U.S. Government Securities		4,781,752,674		3,699,308,868

For the year ended September 30, 2019, purchases and sales related to mortgage dollar rolls were as follows:

Purchases	$	48,518,385,375
Sales		48,527,977,459

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 September 30, 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 September 30, 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 consolidated financial statements.

As of September 30, 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	$	23,839,913,752
Gross unrealized appreciation	$	552,123,498
Gross unrealized depreciation		(179,319,747	)
Net unrealized appreciation	$	372,803,751

9. BANK BORROWINGS

The Master Bond LLC, on behalf of the Master Portfolio, along with certain other funds managed by the Manager and its affiliates (“Participating Funds”), is a party to a 364-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

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Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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 Consolidated 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 September 30, 2019, the Master Portfolio did not borrow under the credit agreement.

10. 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.

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.

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 a mark-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.

The 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 the Master Portfolio.

For OTC options purchased, the Master Portfolio bears the risk of loss in the amount of the premiums paid plus the positive change in market values net of any collateral held by the Master Portfolio should the counterparty fail to perform under the contracts. Options written by the Master Portfolio do not typically give rise to counterparty credit risk, as options written generally obligate the Master Portfolio, and not the counterparty, to perform. The Master Portfolio may be exposed to counterparty credit risk with respect to options written to the extent the Master Portfolio deposits collateral with its counterparty to a written option.

With exchange-traded options purchased and futures and centrally cleared swaps, 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

MASTER PORTFOLIO NOTESTO CONSOLIDATED FINANCIAL STATEMENTS 115

Notes to Consolidated Financial Statements  (continued) Master Total Return Portfolio

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 and centrally cleared swaps 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 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.

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.

116 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Report of Independent Registered Public Accounting Firm

To the Investors of Master Total Return Portfolio and the Board of Directors of Master Bond LLC:

Opinion on the Financial Statements and Financial Highlights

We have audited the accompanying statement of assets and liabilities of Master Total Return Portfolio of Master Bond LLC (the “Fund”), including the schedule of investments, as of September 30, 2019, the related consolidated statement of operations for the year then ended, the consolidated statements of changes in net assets for each of the two years in the period then ended, the consolidated financial highlights for each of the five years in the period then ended, and the related notes. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of September 30, 2019, and 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 then ended, and the financial highlights for each of the five years in the period then ended in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements and financial highlights 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 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 and financial highlights are free of material misstatement, whether due to error or fraud. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Fund’s internal control over financial reporting. Accordingly, we express no such opinion. Our audits included performing procedures to assess the risks of material misstatement of the financial statements and financial highlights, 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 and financial highlights.

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 and financial highlights. Our procedures included confirmation of securities owned as of September 30, 2019, by correspondence with the custodian, agent banks and brokers; when replies were not received from brokers or agent banks, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

Deloitte & Touche LLP

Boston, Massachusetts

November 22, 2019

We have served as the auditor of one or more BlackRock investment companies since 1992.

REPORTOF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM 117

Disclosure of Investment Advisory Agreements and Sub-Advisory Agreements  

The Board of Directors of Master Bond LLC (the “Master LLC”) and the Board of Directors of BlackRock Bond Fund, Inc. (the “Corporation”) met in person on May 1, 2019 (the “May Meeting”) and June 5-6, 2019 (the “June Meeting”) to consider the approval of the investment advisory agreements (the “Advisory Agreements”) between the Master LCC on behalf of Master Total Return Portfolio (the “Master Fund”) and BlackRock Advisors, LLC (the “Manager”) and between the Corporation on behalf of BlackRock Total Return Fund (the “Feeder Fund” and together with the Master Fund the “Funds” and each, a “Fund”), and the Manager, the Master Fund’s and the Feeder Fund’s investment advisor. The Board of Directors of each of the Master LLC and the Corporation also considered the approval of the sub-advisory agreements (collectively, the “Sub-Advisory Agreements”) between the Manager and each of (a) BlackRock International Limited and (b) BlackRock (Singapore) Limited (collectively, the “Sub-Advisors”), with respect to each of the Master Fund and the Feeder Fund. The Feeder Fund is a “feeder” fund that invests all of its investable assets in the Master Fund. Accordingly, the Board of Directors of the Corporation also considered the approval of the Advisory Agreement and the Sub-Advisory Agreements with respect to the Master Fund. The Manager and the Sub-Advisors are referred to herein as “BlackRock.” The Advisory Agreements and the Sub-Advisory Agreements are referred to herein as the “Agreements.” For simplicity: (a) the Board of Directors of the Master LLC and the Board of Directors of the Corporation are referred to herein collectively as the “Board,” and the members are referred to as “Board Members”; and (b) the shareholders of the Feeder Fund and the interest holders of the Master Fund are referred to as “shareholders.”

Activities and Composition of the Board

On the date of the June Meeting, the Board consisted of eleven individuals, nine of whom were not “interested persons” of the Master LLC or the Corporation 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 the Feeder 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 Co-Chairs of the Board are Independent Board Members. The Board has established five standing committees: an Audit Committee, a Governance and Nominating Committee, a Compliance Committee, a Performance Oversight Committee and an Executive Committee, each of which is chaired by an Independent Board Member and composed of Independent Board Members (except for the Executive Committee, which also has one interested Board Member).

The Agreements

Consistent with the requirements of the 1940 Act, the Board considers the continuation of the Agreements on an annual basis. The Board has four quarterly meetings per year, each typically extending for two days, and additional in-person and telephonic meetings throughout the year, as needed. While the Board also has a fifth one-day meeting to consider specific information surrounding the renewals of the Agreements, the Board’s consideration entails a year-long deliberative process whereby the Board and its committees assess BlackRock’s services to the Fund. In particular, the Board assessed, among other things, the nature, extent and quality of the services provided to the Master Fund and the Feeder Fund by BlackRock, BlackRock’s personnel and affiliates, including (as applicable): investment management; accounting, administrative and shareholder services; oversight of the Master Fund’s and Feeder Fund’s service providers; risk management and oversight; legal and compliance services; and ability to meet applicable legal and regulatory requirements. Throughout the year, including during the contract renewal process, the Independent Board Members were advised by independent legal counsel, and met with independent legal counsel in various executive sessions outside of the presence of management.

During the year, the Board, acting directly and through its committees, considers information that is relevant to its annual consideration of the renewal of the Agreements, including the services and support provided by BlackRock to the Master Fund, the Feeder Fund and their shareholders. BlackRock also furnished additional information to the Board in response to specific questions from the Board. This additional information is discussed further below in the section titled “Board Considerations in Approving the Agreements.” Among the matters the Board considered were: (a) investment performance for one-year, three-year, five-year, ten-year, and/or since inception periods, as applicable, against peer funds, applicable benchmarks, and performance metrics, as applicable, as well as senior management’s and portfolio managers’ analyses of the reasons for any over-performance or underperformance relative to its peers, benchmarks, and other performance metrics, as applicable; (b) fees, including advisory, administration, if applicable, and other amounts paid to BlackRock and its affiliates by the Master Fund and/or the Feeder Fund for services; (c) the Master Fund’s and/or the Feeder Fund’s operating expenses and how BlackRock allocates expenses to the Master Fund and the Feeder Fund; (d) the resources devoted to, risk oversight of, and compliance reports relating to, implementation of the Master Fund’s and the Feeder Fund’s investment objective, policies and restrictions, and meeting regulatory requirements; (e) BlackRock and the Master Fund’s and the Feeder Fund’s adherence to applicable compliance policies and procedures; (f) the nature, character and scope of non-investment management services provided by BlackRock and its affiliates and the estimated cost of such services; (g) BlackRock’s and other service providers’ internal controls and risk and compliance oversight mechanisms; (h) BlackRock’s implementation of the proxy voting policies approved by the Board; (i) execution quality of portfolio transactions; (j) BlackRock’s implementation of the Master Fund’s and/or the Feeder Fund’s valuation and liquidity procedures; (k) an analysis of management fees for products with similar investment mandates across the open-end fund, exchange-traded fund (“ETF”), closed-end fund, sub-advised mutual fund, separately managed account, collective investment trust, and institutional separate account product channels, as applicable, and the similarities and differences between these products and the services provided as compared to the Master Fund and/or the Feeder Fund; (l) BlackRock’s compensation methodology for its investment professionals and the incentives and accountability it creates, along with investment professionals’ investments in the fund(s) they manage; and (m) periodic updates on BlackRock’s business.

Board Considerations in Approving the Agreements

The Approval Process:Prior to the May Meeting, the Board requested and received materials specifically relating to the Agreements. The Independent Board Members are continuously engaged in a process with their independent legal counsel and BlackRock to review the nature and scope of the information provided to better assist its deliberations. The materials provided in connection with the May Meeting included, among other things: (a) information independently compiled and prepared by Broadridge Financial Solutions, Inc. (“Broadridge”), based on either a Lipper classification or Morningstar category, regarding fees and expenses of the Master Fund and the Feeder Fund, as applicable, as compared with a peer group of funds as determined by Broadridge (“Expense Peers”), the investment performance of the Feeder Fund as compared with a peer group of funds (“Performance Peers”) and other metrics, as applicable; (b) information on the composition of the Expense Peers and Performance Peers, and a description of Broadridge’s methodology; (c) information on the estimated profits realized by BlackRock and its affiliates pursuant to the Agreements and a discussion of fall-out benefits to BlackRock and its affiliates; (d) a general analysis provided by BlackRock concerning investment management fees received in connection with other types of investment products, such as institutional accounts, sub-advised mutual funds, ETFs, closed-end funds, open-end funds, and separately managed accounts, under similar investment mandates, as well

118 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Disclosure of Investment Advisory Agreements and Sub-Advisory Agreements  (continued)

as the performance of such other products, as applicable; (e) review of non-management fees; (f) the existence, impact and sharing of potential economies of scale, if any, with the Master Fund and the Feeder Fund; (g) a summary of aggregate amounts paid by the Master Fund and/or the Feeder Fund to BlackRock; (h) sales and redemption data regarding the Feeder Fund’s shares; and (i) various additional information requested by the Board as appropriate regarding BlackRock’s, the Master Fund’s and the Feeder Fund’s operations.

At the May Meeting, the Board reviewed materials relating to its consideration of the Agreements. As a result of the discussions that occurred during the May Meeting, and as a culmination of the Board’s year-long deliberative process, the Board presented BlackRock with questions and requests for additional information. BlackRock responded to these requests with additional written information in advance of the June Meeting. Topics covered included: (a) the methodology for measuring estimated fund profitability; (b) economies of scale; (c) fund expenses and potential fee waivers; and (d) differences in services provided and management fees between open-end funds and other product channels.

At the June Meeting, the Board concluded its assessment of, among other things: (a) the nature, extent and quality of the services provided by BlackRock; (b) the investment performance of the Master Fund and the Feeder Fund as compared with Performance Peers and other metrics, as applicable; (c) the advisory fee and the estimated cost of the services and estimated profits realized by BlackRock and its affiliates from their relationship with the Master Fund and the Feeder Fund; (d) the Feeder Fund’s fees and expenses compared to Expense Peers; (e) the sharing of potential economies of scale; (f) fall-out benefits to BlackRock and its affiliates as a result of BlackRock’s relationship with the Master Fund and the Feeder Fund; and (g) other factors deemed relevant by the Board Members.

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 portfolio holdings of the Master Fund. 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 provided by BlackRock, including the investment advisory services and the resulting performance of the Feeder Fund. Throughout the year, the Board compared the Feeder Fund’s performance to the performance of a comparable group of mutual funds, relevant benchmarks, and performance metrics, as applicable. The Board met with BlackRock’s senior management personnel responsible for investment activities, including the senior investment officers. The Board also reviewed the materials provided by the Master Fund’s portfolio management team discussing the Master Fund’s performance and the Master Fund’s investment objective, strategies and outlook.

The Board considered, among other factors, with respect to BlackRock: the number, education and experience of investment personnel generally and the Master Fund’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 Fund’s portfolio management team and BlackRock’s ability to attract and retain high-quality talent and create performance incentives.

In addition to investment advisory services, the Board considered the nature and quality of the administrative and other non-investment advisory services provided to the Master Fund and the Feeder Fund. BlackRock and its affiliates provide the Master Fund and the Feeder Fund with certain administrative, shareholder and other services (in addition to any such services provided to the Master Fund and the Feeder Fund by third parties) and officers and other personnel as are necessary for the operations of the Master Fund and the Feeder Fund. In particular, BlackRock and its affiliates provide the Master Fund and the Feeder Fund 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 Fund and Feeder Fund, 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 certain open-end funds; and (viii) performing or managing administrative functions necessary for the operation of the Master Fund and the Feeder Fund, such as tax reporting, expense management, fulfilling regulatory filing requirements, overseeing the Feeder 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 Fund, the Feeder Fund and BlackRock:The Board, including the Independent Board Members, also reviewed and considered the performance history of the Master Fund and the Feeder Fund, as applicable. The Board noted that the Feeder Fund’s investment results correspond directly to the investment results of the Master Fund. In preparation for the May Meeting, the Board was provided with reports independently prepared by Broadridge, which included a comprehensive analysis of the Feeder Fund’s performance as of December 31, 2018. Broadridge ranks funds in quartiles, ranging from first to fourth, where first is the most desirable quartile position and fourth is the least desirable. In connection with its review, the Board received and reviewed information regarding the investment performance of the Feeder Fund as compared to its Performance Peers. The Board and its Performance Oversight Committee regularly review, and meet with Master Fund management to discuss, the performance of the Master Fund and the Feeder Fund, as applicable, throughout the year.

In evaluating performance, the Board focused particular attention on funds with less favorable performance records. The Board also noted that while it found the data provided by Broadridge generally useful, it recognized the limitations of such data, including in particular, that notable differences may exist between a fund and the Performance Peer funds (for example, the investment objective(s) and investment strategies). Further, the Board recognized that the performance data reflects a snapshot of a period as of a particular date and that selecting a different performance period could produce significantly different results. The Board also acknowledged that long-term performance could be impacted by even one period of significant outperformance or underperformance and that a single investment theme could have the ability to affect long-term performance disproportionately.

The Board noted that for the one-, three- and five-year periods reported, the Feeder Fund ranked in the third, second and first quartiles, respectively, against its Performance Peers. The Board and BlackRock reviewed the Fund’s underperformance during the applicable period.

DISCLOSUREOF INVESTMENT ADVISORY AGREEMENTSAND SUB - ADVISORY AGREEMENTS 119

Disclosure of Investment Advisory Agreements and Sub-Advisory Agreements  (continued)

C. Consideration of the Advisory/Management Fees and the Estimated Cost of the Services and Estimated Profits Realized by BlackRock and its Affiliates from their Relationship with the Master Fund and the Feeder Fund:The Board, including the Independent Board Members, reviewed the Master Fund’s/Feeder Fund’s contractual management fee rate compared with those of the Feeder Fund’s Expense Peers. The contractual management fee rate represents a combination of the advisory fee and any administrative fees, before taking into account any reimbursements or fee waivers. The Board also compared the Feeder Fund’s total expense ratio, as well as the Master Fund’s/Feeder Fund’s actual management fee rate, to those of the Feeder Fund’s Expense Peers. The total expense ratio represents a fund’s total net operating expenses, including any 12b-1 or non 12b-1 service fees. The total expense ratio gives effect to any expense reimbursements or fee waivers that benefit a fund, and the actual management fee rate gives effect to any management fee reimbursements or waivers that benefit a fund. The Board considered 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 and sub-advised mutual funds (including mutual funds sponsored by third parties).

The Board received and reviewed statements relating to BlackRock’s financial condition. The Board reviewed BlackRock’s profitability methodology and was also provided with an estimated profitability analysis that detailed the revenues earned and the expenses incurred by BlackRock for services provided to the Master Fund and the Feeder Fund. The Board reviewed BlackRock’s estimated profitability with respect to the Master Fund and the Feeder Fund, as applicable, and other funds the Board currently oversees for the year ended December 31, 2018 compared to available aggregate estimated profitability data provided for the prior two years. The Board reviewed BlackRock’s estimated profitability with respect to certain other U.S. fund complexes managed by the Manager and/or its affiliates. The Board reviewed BlackRock’s assumptions and methodology of allocating expenses in the estimated profitability analysis, noting the inherent limitations in allocating costs among various advisory products. The Board recognized that profitability may be affected by numerous factors including, among other things, fee waivers and expense reimbursements by the Manager, the types of funds managed, precision of expense allocations and business mix. The Board thus recognized that calculating and comparing profitability at individual fund levels is difficult.

The Board noted that, in general, individual fund or product line profitability of other advisors is not publicly available. The Board reviewed BlackRock’s overall operating margin, in general, compared to that of certain other publicly-traded asset management firms. The Board considered the differences between BlackRock and these other firms, including the contribution of technology at BlackRock, BlackRock’s expense management, and the relative product mix.

In addition, the Board considered the estimated cost of the services provided to the Master Fund and the Feeder Fund by BlackRock, and BlackRock’s and its affiliates’ estimated profits relating to the management of the Master Fund and the Feeder Fund and the other funds advised by BlackRock and its affiliates. As part of its analysis, the Board reviewed BlackRock’s methodology in allocating its costs of managing the Master Fund and the Feeder Fund. The Board considered whether BlackRock has the financial resources necessary to attract and retain high quality investment management personnel to perform its obligations under the Agreements and to continue to provide the high quality of services that is expected by the Board. The Board further considered factors including but not limited to BlackRock’s commitment of time, assumption of risk, and liability profile in servicing the Master Fund and the Feeder Fund, including in contrast to what is required of BlackRock with respect to other products with similar investment mandates across the open-end fund, ETF, closed-end fund, sub-advised mutual fund, separately managed account, collective investment trust, and institutional separate account product channels, as applicable.

The Board noted that the Master Fund’s/Feeder Fund’s contractual management fee rate ranked in the second quartile, and that the actual management fee rate and Feeder Fund’s total expense ratio ranked in the third and first quartiles, respectively, relative to the Master Fund’s/Feeder Fund’s Expense Peers, as applicable. The Board also noted that the Master Fund has an advisory fee arrangement that includes breakpoints that adjust the fee rate downward as the size of the Master Fund increases above certain contractually specified levels. The Board noted that if the size of the Master Fund were to decrease, the Master Fund could lose the benefit of one or more breakpoints. The Board further noted that the Feeder Fund has an advisory fee arrangement that includes breakpoints that adjust the fee rate downward as the size of the Feeder Fund increases above certain contractually specified levels. The Board noted that if the size of the Feeder Fund were to decrease, the Feeder Fund could lose the benefit of one or more breakpoints. The Board noted that BlackRock and the Board have contractually agreed to a cap on the Feeder Fund’s total expenses as a percentage of the Feeder Fund’s average daily net assets on a class-by-class basis.

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 Fund and the Feeder Fund 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. The Board also considered the extent to which the Master Fund and the Feeder Fund benefit from such economies in a variety of ways, and whether there should be changes in the advisory fee rate or breakpoint structure in order to enable the Master Fund and the Feeder Fund to more fully participate in these economies of scale. The Board considered the Master Fund’s asset levels and whether the current fee schedule was appropriate. In its consideration, the Board Members took into account the existence of any expense caps and further considered the continuation and/or implementation, as applicable, of such caps.

E. Other Factors Deemed Relevant by the Board Members:The Board, including 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 Fund and the Feeder Fund, 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 Fund and the Feeder Fund, including for 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 Agreements, the Board also received information regarding BlackRock’s brokerage and soft dollar practices. The Board received reports from BlackRock which included information on brokerage commissions and trade execution practices throughout the year.

The Board noted the competitive nature of the open-end fund marketplace, and that shareholders are able to redeem their Feeder Fund shares if they believe that the Feeder Fund’s and/or the Master Fund’s fees and expenses are too high or if they are dissatisfied with the performance of the Feeder Fund.

120 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Disclosure of Investment Advisory Agreements and Sub-Advisory Agreements  (continued)

Conclusion

The Board of each of the Master LLC and the Corporation, including the Independent Board Members, approved the continuation of the Advisory Agreements between the Manager and each of the Master LLC, on behalf of the Master Fund, and the Corporation, on behalf of the Feeder Fund, for a one-year term ending June 30, 2020, and the Sub-Advisory Agreements between the Manager and the Sub-Advisors, with respect to the Master Fund and the Feeder Fund, respectively, for a one-year term ending June 30, 2020. Based upon its evaluation of all of the aforementioned factors in their totality, as well as other information, the Board, including the Independent Board Members, was satisfied that the terms of the Agreements were fair and reasonable and in the best interest of the Funds and their respective shareholders. The Board of the Corporation, including the Independent Board Members, also considered the continuation of the Agreements with respect to the Master Fund and found the Agreements to be satisfactory. In arriving at its decision to approve the Agreements, the Board did not identify any single factor or group of factors as all-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 AGREEMENTSAND SUB -ADVISORY AGREEMENTS 121

Director and Officer Information

Independent Directors (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
Richard E. Cavanagh 1946	Co-Chair of the Board and Director (Since 2019)	Director, The Guardian Life Insurance Company of America since 1998; Board Chair, Volunteers of America (a not-for-profit organization) from 2015 to 2018 (board member since 2009); Director, Arch Chemicals (chemical and allied products) from 1999 to 2011; Trustee, Educational Testing Service from 1997 to 2009 and Chairman thereof from 2005 to 2009; Senior Advisor, The Fremont Group since 2008 and Director thereof since 1996; Faculty Member/Adjunct Lecturer, Harvard University since 2007 and Executive Dean from 1987 to 1995; President and Chief Executive Officer, The Conference Board, Inc. (global business research organization) from 1995 to 2007.	86 RICs consisting of 110 Portfolios	None
Karen P. Robards 1950	Co-Chair of the Board and Director (Since 2019)	Principal of Robards & Company, LLC (consulting and private investing) since 1987; Co-founder and Director of the Cooke Center for Learning and Development (a not-for-profit organization) since 1987; Director of Enable Injections, LLC (medical devices) since 2019; Investment Banker at Morgan Stanley from 1976 to 1987.	86 RICs consisting of 110 Portfolios	Greenhill & Co., Inc.; AtriCure, Inc. (medical devices) from 2000 until 2017
Michael J. Castellano 1946	Director (Since 2019)	Chief Financial Officer of Lazard Group LLC from 2001 to 2011; Chief Financial Officer of Lazard Ltd from 2004 to 2011; Director, Support Our Aging Religious (non-profit) from 2009 to June 2015 and since 2017; Director, National Advisory Board of Church Management at Villanova University since 2010; Trustee, Domestic Church Media Foundation since 2012; Director, CircleBlack Inc. (financial technology company) since 2015.	86 RICs consisting of 110 Portfolios	None
Cynthia L. Egan 1955	Director (Since 2019)	Advisor, U.S. Department of the Treasury from 2014 to 2015; President, Retirement Plan Services, for T. Rowe Price Group, Inc. from 2007 to 2012; executive positions within Fidelity Investments from 1989 to 2007.	86 RICs consisting of 110 Portfolios	Unum (insurance); The Hanover Insurance Group (insurance); Envestnet (investment platform) from 2013 until 2016
Frank J. Fabozzi(d) 1948	Director (Since 2019)	Editor of The Journal of Portfolio Management since 1986; Professor of Finance, EDHEC Business School (France) since 2011; Visiting Professor, Princeton University for the 2013 to 2014 academic year and Spring 2017 semester; Professor in the Practice of Finance, Yale University School of Management from 1994 to 2011 and currently a Teaching Fellow in Yale’s Executive Programs; Board Member, BlackRock Equity-Liquidity Funds from 2014 to 2016; affiliated professor Karlsruhe Institute of Technology from 2008 to 2011.	87 RICs consisting of 111 Portfolios	None
Henry Gabbay 1947	Director (Since 2007)	Board Member, BlackRock Equity-Bond Board from 2007 to 2018; Board Member, BlackRock Equity-Liquidity and BlackRock Closed-End Fund Boards from 2007 through 2014; Consultant, BlackRock, Inc. from 2007 to 2008; Managing Director, BlackRock, Inc. from 1989 to 2007; Chief Administrative Officer, BlackRock Advisors, LLC from 1998 to 2007; President of BlackRock Funds and BlackRock Allocation Target Shares (formerly, BlackRock Bond Allocation Target Shares) from 2005 to 2007 and Treasurer of certain closed-end funds in the BlackRock fund complex from 1989 to 2006.	86 RICs consisting of 110 Portfolios	None

122 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Director and Officer Information  (continued)

		Independent Directors (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
R. Glenn Hubbard 1958	Director (Since 2019)	Dean, Columbia Business School from 2004 to 2019; Faculty member, Columbia Business School since 1988.	86 RICs consisting of 110 Portfolios	ADP (data and information services); Metropolitan Life Insurance Company (insurance); KKR Financial Corporation (finance) from 2004 until 2014
W. Carl Kester(d) 1951	Director (Since 2019)	George Fisher Baker Jr. Professor of Business Administration, Harvard Business School since 2008; Deputy Dean for Academic Affairs from 2006 to 2010; Chairman of the Finance Unit, from 2005 to 2006; Senior Associate Dean and Chairman of the MBA Program from 1999 to 2005; Member of the faculty of Harvard Business School since 1981.	87 RICs consisting of 111 Portfolios	None
Catherine A. Lynch(d) 1961	Director (Since 2019)	Chief Executive Officer, Chief Investment Officer and various other positions, National Railroad Retirement Investment Trust from 2003 to 2016; Associate Vice President for Treasury Management, The George Washington University from 1999 to 2003; Assistant Treasurer, Episcopal Church of America from 1995 to 1999.	87 RICs consisting of 111 Portfolios	None
Interested Directors (a)(e)
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	Director (Since 2015)	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 289 Portfolios	None
John M. Perlowski(d) 1964	Director (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 290 Portfolios	None

^(a)  The address of each Director is c/o BlackRock, Inc., 55 East 52nd Street, New York, New York 10055.

^(b)  Each Independent Director holds office until his or her successor is duly elected and qualifies or until his or her earlier death, resignation, retirement or removal as provided by the Corporation/Master Bond LLC’s by-laws or charter or statute, or until December 31 of the year in which he or she turns 75. Directors who are “interested persons,” as defined in the Investment Company Act serve until their successor is duly elected and qualifies or until their earlier death, resignation, retirement or removal as provided by the Corporation/Master Bond LLC’s by-laws or statute, or until December 31 of the year in which they turn 72. The Board may determine to extend the terms of Independent Directors on a case-by-case basis, as appropriate.

^(c)  Following the combination of Merrill Lynch Investment Managers, L.P. (“MLIM”) and BlackRock, Inc. in September 2006, the various legacy MLIM and legacy BlackRock fund boards were realigned and consolidated into three new fund boards in 2007. Certain Independent Directors first became members of the boards of other legacy MLIM or legacy BlackRock funds as follows: Richard E. Cavanagh, 1994; Frank J. Fabozzi, 1988; R. Glenn Hubbard, 2004; W. Carl Kester, 1995; and Karen P. Robards, 1998. Certain other Independent Directors became members of the boards of the closed-end funds in the Fixed-Income Complex as follows: Michael J. Castellano, 2011; Cynthia L. Egan, 2016; and Catherine A. Lynch, 2016.

^(d)  Dr. Fabozzi, Dr. Kester, Ms. Lynch and Mr. Perlowski are also trustees of the BlackRock Credit Strategies Fund.

^(e)  Mr. Fairbairn and Mr. Perlowski are both “interested persons,” as defined in the 1940 Act, of the Corporation/Master Bond LLC based on their positions with BlackRock, Inc. and its affiliates. Mr. Fairbairn and Mr. Perlowski are also board members of the BlackRock Multi-Asset Complex.

DIRECTORAND OFFICER INFORMATION 123

Director and Officer Information  (continued)

Officers Who Are Not Directors (a)
Name Year of Birth(b)	Position(s) Held (Length of Service)	Principal Occupation(s) During Past Five Years
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 2007)	Chief Financial Officer of the iShares® exchange traded funds since 2019; Managing Director of BlackRock, Inc. since 2006.
Jay M. Fife 1970	Treasurer (Since 2007)	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 Corporation/Master Bond LLC serve at the pleasure of the Board.

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

Effective September 4, 2019, Janey Ahn replaced Benjamin Archibald as the Secretary of the Corporation/Master Bond LLC.

Effective September 5, 2019, Lisa Belle replaced John MacKessy as the Anti-Money Laundering Compliance Officer of the Corporation/Master Bond LLC.

Investment Adviser

BlackRock Advisors, LLC

Wilmington, DE 19809

Sub-Advisers

BlackRock International Limited

Edinburgh, EH3 8BL

United Kingdom

BlackRock (Singapore) Limited

079912 Singapore

Accounting Agent and Transfer Agent

BNY Mellon Investment Servicing (US) Inc.

Wilmington, DE 19809

Custodian

The Bank of New York Mellon

New York, NY 10286

Independent Registered Public Accounting Firm

Deloitte & Touche LLP

Boston, MA 19103

Distributor

BlackRock Investments, LLC

New York, NY 10022

Legal Counsel

Willkie Farr & Gallagher LLP

New York, NY 10019

Address of the Corporation/Master Bond LLC

100 Bellevue Parkway

Wilmington, DE 19809

124 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 Bond LLC 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 Bond LLC’s Forms N-PORT and N-Q are available on the SEC’s website at http://www.sec.gov. The Fund’s/Master Bond LLC’s Forms N-PORT and 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 Bond LLC 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) athttp://www.blackrock.com; and (3) on the SEC’s website at http://www.sec.gov.

Availability of Proxy Voting Record

Information about how the Fund/Master Bond LLC voted proxies relating to securities held in the Fund/Master Bond LLC’s portfolios during the most recent 12-month period ended June 30 is available upon request and without charge (1) athttp://www.blackrock.comor by calling (800) 441-7762 and (2) on the SEC’s website at http://www.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. Visithttp://www.blackrock.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 reach us on the Web athttp://www.blackrock.com.

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 125

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.

126 2019 BLACKROCK ANNUAL REPORTTO SHAREHOLDERS

Glossary of Terms Used in this Report

Currency
ARS	Argentine Peso
AUD	Australian Dollar
BRL	Brazilian Real
CAD	Canadian Dollar
CHF	Swiss Franc
CLP	Chilean Peso
CNH	Chinese Yuan Offshore
COP	Colombian Peso
DKK	Danish Krone
EGP	Egyptian Pound
EUR	Euro
GBP	British Pound
HKD	Hong Kong Dollar
IDR	Indonesian Rupiah
INR	Indian Rupee
JPY	Japanese Yen
KRW	South Korean Won
MXN	Mexican Peso
NOK	Norwegian Krone
NZD	New Zealand Dollar
PEN	Peruvian Sol
RUB	Russian Ruble
SGD	Singapore Dollar
SEK	Swedish Krona
TRY	Turkish Lira
TWD	Taiwan New Dollar
USD	US Dollar
ZAR	South African Rand

Portfolio Abbreviations
ABS	Asset-Backed Security
AGM	Assurance Guaranty Municipal Corp.
AKA	Also Known As
AMBAC	AMBAC Assurance Corp.
BZDIOVER	Overnight Brazil CETIP — Interbank Rate
CBOT	Chicago Board of Trade
CIBOR	Copenhagen Interbank Offered Rate
CLO	Collateralized Loan Obligation
CME	Chicago Mercantile Exchange
CMS	Constant Maturity Swap
DAC	Designated Activity Company
ETF	Exchange-Traded Fund
EURIBOR	Euro Interbank Offered Rate
FKA	Formerly Known As
GNMA	Government National Mortgage Association
GO	General Obligation Bonds
KBW	Keefe, Bruyette & Woods
LIBOR	London Interbank Offered Rate
MSCI	Morgan Stanley Capital International
MXIBTIIE	Mexico Interbank TIIE 28-Day
NIBOR	Norwegian Interbank Offered Rate
OTC	Over-the-counter
PIK	Payment-in-kind
PSF	Permanent School Fund
RB	Revenue Bonds
REMIC	Real Estate Mortgage Investment Conduit
S&P	Standard & Poor’s
SCSDE	South Carolina State Department of Education
SPDR	Standard & Poor’s Depositary Receipts
STIBOR	Stockholm Interbank Offered Rate
TA	Tax Allocation
TBA	To-be-announced

GLOSSARYOF TERMS USEDINTHIS REPORT 127

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 Funds unless preceded or accompanied by the 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.

TR-9/19-AR

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 other non-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 experts serving on its audit committee and (ii) each audit committee financial expert is independent:
	Michael Castellano
	Frank J. Fabozzi
	Henry Gabbay
	Catherine A. Lynch
	Karen P. Robards
	The registrants’ board of directors has determined that Karen P. Robards qualifies as an audit committee financial expert pursuant to Item 3(c)(4) of FormN-CSR.
	Ms. Robards has a thorough understanding of generally accepted accounting principles, financial statements and internal control over financial reporting as well as audit committee functions. Ms. Robards has been President of Robards & Company, a financial advisory firm, since 1987. Ms. Robards was formerly an investment banker for more than 10 years where she was responsible for evaluating and assessing the performance of companies based on their financial results. Ms. Robards has over 30 years of experience analyzing financial statements. She also is a member of the audit committee of one publicly held company and anon-profit organization.
	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.

2

Item 4 –	Principal Accountant Fees and Services
	The following table presents fees billed by Deloitte & Touche LLP (“D&T”) 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 Total Return Fund of BlackRock Bond Fund, Inc.	$8,160	$8,160	$0	$0	$16,000	$16,000	$0	$0
Master Total Return Portfolio of Master Bond LLC	$85,068	$85,068	$0	$39	$20,000	$20,000	$0	$0

The following table presents fees billed by D&T that were required to be approved by each registrant’s audit committee (the “Committee”) for services that relate directly to the operations or financial reporting of the Funds and that are rendered on behalf of BlackRock Advisors, LLC (“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 the Funds (“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	$2,050,500	$2,274,000

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.

³Non-audit fees of $2,050,500 and $2,274,000 for the current fiscal year and previous fiscal year, respectively, were paid to each Fund’s principal accountant in their entirety by BlackRock, in connection with services provided to the Affiliated Service Providers of each Fund and of certain other funds sponsored and advised by BlackRock or its affiliates for a service organization review and an accounting research tool subscription. These amounts represent aggregate fees paid by BlackRock and were not allocated on a per fund basis.

(e)(1) Audit CommitteePre-Approval Policies and Procedures:

The Committee has adopted policies and procedures with regard to thepre-approval of services. Audit, audit-related and tax compliance services provided to the registrants on an annual basis require specificpre-approval by the Committee. The Committee also must approve othernon-audit services provided to the registrants 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 registrants. 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 registrants which have a direct impact on the operations or financial reporting of the registrants will only be deemedpre-approved provided that any individual project does not exceed $10,000 attributable to the registrants 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 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 general pre-approval

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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 the Committee pursuant to the de minimis 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 registrants, the Investment Adviser and the Affiliated Service Providers were:

Entity Name	Current Fiscal Year   End	Previous Fiscal Year   End
BlackRock Total Return Fund of BlackRock Bond Fund, Inc.	$16,000	$16,000
Master Total Return Portfolio of Master Bond LLC	$20,000	$20,039

Additionally, the amounts billed by D&T in connection with services provided to the Affiliated Service Providers of the Funds and of other funds sponsored and advised by BlackRock or its affiliates during the current and previous fiscal years for a service organization review and an accounting research tool subscription were:

Current Fiscal Year     End	Previous Fiscal Year     End
$2,050,500	$2,274,000

These amounts represent aggregate fees paid by BlackRock and were not allocated on a per fund basis.

(h) The 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) of Rule2-01 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

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Item 8 – Portfolio Managers of Closed-End Management Investment Companies – Not Applicable

Item 9 – Purchases of Equity Securities byClosed-End Management Investment Company and Affiliated Purchasers – Not Applicable

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 Rule15d-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 Total Return Fund of BlackRock Bond Fund, Inc. and Master Total Return Portfolio of Master Bond LLC

By:	/s/ John M. Perlowski
	John M. Perlowski
	Chief Executive Officer (principal executive officer) of
	BlackRock Total Return Fund of BlackRock Bond Fund, Inc. and Master Total Return Portfolio of Master Bond LLC
Date: December 3, 2019
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 Total Return Fund of BlackRock Bond Fund, Inc. and Master Total Return Portfolio of Master Bond LLC
Date: December 3, 2019
By:	/s/ Neal J. Andrews
	Neal J. Andrews
	Chief Financial Officer (principal financial officer) of
	BlackRock Total Return Fund of BlackRock Bond Fund, Inc. and Master Total Return Portfolio of Master Bond LLC
Date:	December 3, 2019

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