Fidelity Real Estate Index Fund NCSR Certified annual shareholder report (management investment company)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811-02105

Fidelity Salem Street Trust

(Exact name of registrant as specified in charter)

245 Summer St., Boston, Massachusetts 02210

(Address of principal executive offices) (Zip code)

Cynthia Lo Bessette, Secretary

245 Summer St.

Boston, Massachusetts 02210

(Name and address of agent for service)

Registrant's telephone number, including area code:

617-563-7000


Date of fiscal year end:	February 28

Date of reporting period:	February 28, 2021

Item 1.

Reports to Stockholders

Fidelity® SAI Long-Term Treasury Bond Index Fund

Offered exclusively to certain clients of the Adviser or its affiliates - not available for sale to the general public. Fidelity SAI is a product name of Fidelity^® funds dedicated to certain programs affiliated with Strategic Advisers LLC.

Annual Report

February 28, 2021

Contents

Note to Shareholders
Performance
Management's Discussion of Fund Performance
Investment Summary
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions
Board Approval of Investment Advisory Contracts and Management Fees
Liquidity Risk Management Program

To view a fund's proxy voting guidelines and proxy voting record for the 12-month period ended June 30, visit http://www.fidelity.com/proxyvotingresults or visit the Securities and Exchange Commission's (SEC) web site at http://www.sec.gov.

You may also call 1-800-544-3455 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

This report and the financial statements contained herein are submitted for the general information of the shareholders of the Fund. This report is not authorized for distribution to prospective investors in the Fund unless preceded or accompanied by an effective prospectus.

A fund files its complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-PORT. Forms N-PORT are available on the SEC’s web site at http://www.sec.gov. A fund's Forms N-PORT may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information regarding the operation of the SEC's Public Reference Room may be obtained by calling 1-800-SEC-0330.

For a complete list of a fund's portfolio holdings, view the most recent holdings listing, semiannual report, or annual report on Fidelity's web site at http://www.fidelity.com, http://www.institutional.fidelity.com, or http://www.401k.com, as applicable.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Early in 2020, the outbreak and spread of a new coronavirus emerged as a public health emergency that had a major influence on financial markets, primarily based on its impact on the global economy and the outlook for corporate earnings. The virus causes a respiratory disease known as COVID-19. On March 11, 2020 the World Health Organization declared the COVID-19 outbreak a pandemic, citing sustained risk of further global spread.

In the weeks following, as the crisis worsened, we witnessed an escalating human tragedy with wide-scale social and economic consequences from coronavirus-containment measures. The outbreak of COVID-19 prompted a number of measures to limit the spread, including travel and border restrictions, quarantines, and restrictions on large gatherings. In turn, these resulted in lower consumer activity, diminished demand for a wide range of products and services, disruption in manufacturing and supply chains, and – given the wide variability in outcomes regarding the outbreak – significant market uncertainty and volatility. Amid the turmoil, global governments and central banks took unprecedented action to help support consumers, businesses, and the broader economies, and to limit disruption to financial systems.

The situation continues to unfold, and the extent and duration of its impact on financial markets and the economy remain highly uncertain. Extreme events such as the coronavirus crisis are “exogenous shocks” that can have significant adverse effects on mutual funds and their investments. Although multiple asset classes may be affected by market disruption, the duration and impact may not be the same for all types of assets.

Fidelity is committed to helping you stay informed amid news about COVID-19 and during increased market volatility, and we’re taking extra steps to be responsive to customer needs. We encourage you to visit our websites, where we offer ongoing updates, commentary, and analysis on the markets and our funds.

Performance: The Bottom Line

Average annual total return reflects the change in the value of an investment, assuming reinvestment of distributions from dividend income and capital gains (the profits earned upon the sale of securities that have grown in value, if any) and assuming a constant rate of performance each year. The hypothetical investment and the average annual total returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. During periods of reimbursement by Fidelity, a fund’s total return will be greater than it would be had the reimbursement not occurred. How a fund did yesterday is no guarantee of how it will do tomorrow.

Average Annual Total Returns

For the periods ended February 28, 2021	Past 1 year	Past 5 years	Life of fund^A
Fidelity® SAI Long-Term Treasury Bond Index Fund	(6.39)%	4.28%	5.45%

^A From October 8, 2015

$10,000 Over Life of Fund

Let's say hypothetically that $10,000 was invested in Fidelity® SAI Long-Term Treasury Bond Index Fund on October 8, 2015, when the fund started.

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. 20+ Year Treasury Bond Index performed over the same period.

	Period Ending Values
	$13,319	Fidelity® SAI Long-Term Treasury Bond Index Fund
	$13,316	Bloomberg Barclays U.S. 20+ Year Treasury Bond Index

Management's Discussion of Fund Performance

Market Recap: U.S. taxable investment-grade bonds posted only a small gain for the 12 months ending February 28, 2021, hampered by rising long-term market rates amid faster economic expansion. The Bloomberg Barclays U.S. Aggregate Bond Index added 1.38% for the period. Spreads for corporate bonds widened and yields rose in March 2020 due to robust investor demand for relatively safer assets – especially U.S. Treasury bonds – as the outbreak and spread of COVID-19 threatened global economic growth and corporate earnings, leading to pockets of market illiquidity. Aggressive intervention by the U.S. Federal Reserve boosted liquidity and led to a broad rally for fixed-income assets from April through July. Spreads widened moderately in August and September, amid healthy issuance of new corporate bonds, then narrowed through period end. In February 2021, yields rose because a $1.9 trillion COVID-relief bill offered hopes for a broad economic recovery but led to rising inflation expectations. Within the Bloomberg Barclays index, corporate bonds gained 2.79% for the 12 months, topping the -0.13% return of U.S. Treasuries. Securitized sectors, meanwhile, outpaced Treasuries and the broader market. Outside the index, U.S. corporate high-yield bonds gained 9.38% and Treasury Inflation-Protected Securities (TIPS) rose 5.85%.

Comments from Co-Portfolio Managers Brandon Bettencourt and Richard Munclinger: For the fiscal year, the fund returned -6.39%, nearly in line, net of fees, with the -6.25% return of the benchmark, the Bloomberg Barclays 20+ Year Treasury Bond Index. This result met our goal of producing monthly returns, before expenses, that closely match the benchmark’s return. We use a method known as stratified sampling, which matches the index’s risk factors, but does not always hold all bonds in the exact proportions of the index. Early in the period, Treasuries posted very strong gains as the U.S. Federal Reserve cut the federal funds rate and undertook massive quantitative easing to support the economy and the financial markets amid the onset of the COVID-19 pandemic. Longer-term Treasury yields declined through August, then began an uptrend that continued through period end. Treasuries came under significant pressure in early 2021 when investors gravitated toward riskier assets and away from U.S. government bonds, anticipating a rebounding economy and a potential return of inflation in light of accommodative monetary policy and expansive fiscal spending. For the year, long-maturity Treasuries, with their greater sensitivity to interest-rate movements, posted a loss as the yield curve steepened. Shorter-term Treasuries posted modest gains.

The views expressed above reflect those of the portfolio manager(s) only through the end of the period as stated on the cover of this report and do not necessarily represent the views of Fidelity or any other person in the Fidelity organization. Any such views are subject to change at any time based upon market or other conditions and Fidelity disclaims any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for a Fidelity fund are based on numerous factors, may not be relied on as an indication of trading intent on behalf of any Fidelity fund.

Note to shareholders: On October 1, 2020, Richard Munclinger assumed co-management responsibilities for the fund, succeeding Jay Small.

Investment Summary (Unaudited)

Coupon Distribution as of February 28, 2021

	% of fund's investments
1 - 1.99%	12.8
2 - 2.99%	38.9
3 - 3.99%	46.5
4 - 4.99%	1.1

Coupon distribution shows the range of stated interest rates on the fund's investments, excluding short-term investments.

Asset Allocation (% of fund's net assets)

As of February 28, 2021
	U.S. Treasury Obligations	99.6%
	Short-Term Investments and Net Other Assets (Liabilities)	0.4%

Schedule of Investments February 28, 2021

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.6%
	Principal Amount	Value
U.S. Treasury Obligations - 99.6%
U.S. Treasury Bonds:
1.25% 5/15/50	$70,149,000	$56,650,798
1.375% 8/15/50	42,138,000	35,178,646
1.625% 11/15/50	41,976,000	37,325,846
1.875% 2/15/51	23,004,000	21,781,913
2% 2/15/50	44,297,800	43,150,556
2.25% 8/15/46	20,328,000	20,884,638
2.25% 8/15/49	29,316,000	30,158,835
2.375% 11/15/49	10,154,000	10,730,716
2.5% 2/15/45	21,542,700	23,176,074
2.5% 2/15/46	283,000	304,557
2.5% 5/15/46	23,918,000	25,727,733
2.75% 8/15/42	15,408,500	17,354,425
2.75% 11/15/42	26,219,100	29,498,536
2.75% 8/15/47	22,049,000	24,942,070
2.75% 11/15/47	38,530,000	43,591,578
2.875% 5/15/43	35,659,200	40,981,614
2.875% 8/15/45	18,898,100	21,735,768
2.875% 11/15/46	29,142,000	33,619,167
2.875% 5/15/49	79,380,000	92,583,550
3% 5/15/42	8,459,700	9,904,128
3% 11/15/44	52,231,800	61,221,383
3% 5/15/45	11,614,800	13,640,131
3% 11/15/45	18,670,000	21,948,190
3% 2/15/47	24,007,000	28,366,709
3% 5/15/47	17,515,000	20,712,172
3% 2/15/48	59,011,000	69,969,527
3% 8/15/48	25,393,000	30,163,115
3% 2/15/49	35,485,000	42,247,942
3.125% 11/15/41	6,159,700	7,355,067
3.125% 2/15/42	7,568,100	9,038,558
3.125% 2/15/43	29,348,600	35,050,941
3.125% 8/15/44	14,630,300	17,494,067
3.125% 5/15/48	41,548,000	50,386,688
3.375% 5/15/44	25,996,800	32,302,039
3.375% 11/15/48	35,568,000	45,186,643
3.625% 8/15/43	4,114,600	5,297,226
3.625% 2/15/44	19,146,500	24,684,027
3.75% 8/15/41	14,794,700	19,259,694
3.75% 11/15/43	3,083,100	4,043,197
4.375% 5/15/41	8,927,700	12,566,435
		1,170,214,899
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $1,211,031,059)		1,170,214,899
	Shares	Value

Money Market Funds - 0.7%
Fidelity Cash Central Fund 0.07% (a)	8,259,919	$8,261,571
TOTAL MONEY MARKET FUNDS
(Cost $8,261,571)		8,261,571
TOTAL INVESTMENT IN SECURITIES - 100.3%
(Cost $1,219,292,630)		1,178,476,470
NET OTHER ASSETS (LIABILITIES) - (0.3)%		(3,841,331)
NET ASSETS - 100%		$1,174,635,139

Legend

(a) Affiliated fund that is generally available only to investment companies and other accounts managed by Fidelity Investments. The rate quoted is the annualized seven-day yield of the fund at period end. A complete unaudited listing of the fund's holdings as of its most recent quarter end is available upon request. In addition, each Fidelity Central Fund's financial statements, which are not covered by the Fund's Report of Independent Registered Public Accounting Firm, are available on the SEC's website or upon request.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$3,233
Fidelity Securities Lending Cash Central Fund	7,150
Total	$10,383

Amounts in the income column in the above table include any capital gain distributions from underlying funds, which are presented in the corresponding line-item in the Statement of Operations, if applicable. Amount for Fidelity Securities Lending Cash Central Fund represents the income earned on investing cash collateral, less rebates paid to borrowers and any lending agent fees associated with the loan, plus any premium payments received for lending certain types of securities.

Investment Valuation

The following is a summary of the inputs used, as of February 28, 2021, involving the Fund's assets and liabilities carried at fair value. The inputs or methodology used for valuing securities may not be an indication of the risk associated with investing in those securities. For more information on valuation inputs, and their aggregation into the levels used below, please refer to the Investment Valuation section in the accompanying Notes to Financial Statements.

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$1,170,214,899	$--	$1,170,214,899	$--
Money Market Funds	8,261,571	8,261,571	--	--
Total Investments in Securities:	$1,178,476,470	$8,261,571	$1,170,214,899	$--

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

		February 28, 2021
Assets
Investment in securities, at value — See accompanying schedule: Unaffiliated issuers (cost $1,211,031,059)	$1,170,214,899
Fidelity Central Funds (cost $8,261,571)	8,261,571
Total Investment in Securities (cost $1,219,292,630)		$1,178,476,470
Receivable for investments sold		13,031,709
Interest receivable		5,122,545
Distributions receivable from Fidelity Central Funds		214
Prepaid expenses		788
Receivable from investment adviser for expense reductions		17,332
Total assets		1,196,649,058
Liabilities
Payable for investments purchased	$21,787,107
Payable for fund shares redeemed	145,143
Distributions payable	391
Accrued management fee	39,319
Other payables and accrued expenses	41,959
Total liabilities		22,013,919
Net Assets		$1,174,635,139
Net Assets consist of:
Paid in capital		$1,235,964,306
Total accumulated earnings (loss)		(61,329,167)
Net Assets		$1,174,635,139
Net Asset Value, offering price and redemption price per share ($1,174,635,139 ÷ 106,420,010 shares)		$11.04

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended February 28, 2021
Investment Income
Interest		$19,498,283
Income from Fidelity Central Funds (including $7,150 from security lending)		10,383
Total income		19,508,666
Expenses
Management fee	$434,428
Custodian fees and expenses	9,303
Independent trustees' fees and expenses	3,338
Registration fees	31,518
Audit	55,030
Legal	1,226
Miscellaneous	4,095
Total expenses before reductions	538,938
Expense reductions	(208,536)
Total expenses after reductions		330,402
Net investment income (loss)		19,178,264
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	52,750,945
Fidelity Central Funds	923
Total net realized gain (loss)		52,751,868
Change in net unrealized appreciation (depreciation) on:
Investment securities:
Unaffiliated issuers	(143,186,691)
Fidelity Central Funds	(19)
Total change in net unrealized appreciation (depreciation)		(143,186,710)
Net gain (loss)		(90,434,842)
Net increase (decrease) in net assets resulting from operations		$(71,256,578)

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended February 28, 2021	Year ended February 29, 2020
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$19,178,264	$7,679,418
Net realized gain (loss)	52,751,868	1,592,963
Change in net unrealized appreciation (depreciation)	(143,186,710)	101,908,235
Net increase (decrease) in net assets resulting from operations	(71,256,578)	111,180,616
Distributions to shareholders	(64,192,638)	(7,507,765)
Share transactions
Proceeds from sales of shares	537,924,057	911,451,355
Reinvestment of distributions	64,151,400	6,133,403
Cost of shares redeemed	(347,431,166)	(26,055,371)
Net increase (decrease) in net assets resulting from share transactions	254,644,291	891,529,387
Total increase (decrease) in net assets	119,195,075	995,202,238
Net Assets
Beginning of period	1,055,440,064	60,237,826
End of period	$1,174,635,139	$1,055,440,064
Other Information
Shares
Sold	42,926,648	79,471,027
Issued in reinvestment of distributions	5,248,178	524,505
Redeemed	(25,613,107)	(2,332,959)
Net increase (decrease)	22,561,719	77,662,573

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity SAI Long-Term Treasury Bond Index Fund


Years ended February 28,	2021	2020 ^A	2019	2018	2017
Selected Per–Share Data
Net asset value, beginning of period	$12.59	$9.72	$9.59	$9.86	$10.69
Income from Investment Operations
Net investment income (loss)^B	.227	.251	.292	.278	.271
Net realized and unrealized gain (loss)	(.965)	2.876	.123	(.272)	(.767)
Total from investment operations	(.738)	3.127	.415	.006	(.496)
Distributions from net investment income	(.226)	(.257)	(.285)	(.276)	(.268)
Distributions from net realized gain	(.586)	–	–	–	(.066)
Total distributions	(.812)	(.257)	(.285)	(.276)	(.334)
Net asset value, end of period	$11.04	$12.59	$9.72	$9.59	$9.86
Total Return^C,^D	(6.39)%	32.55%	4.38%	(.03)%	(4.77)%
Ratios to Average Net Assets^E,^F
Expenses before reductions	.05%	.08%	.20%	.18%	.16%
Expenses net of fee waivers, if any	.03%	.03%	.03%	.06%	.11%
Expenses net of all reductions	.03%	.03%	.03%	.06%	.11%
Net investment income (loss)	1.77%	2.21%	2.99%	2.77%	2.57%
Supplemental Data
Net assets, end of period (000 omitted)	$1,174,635	$1,055,440	$60,238	$825,447	$764,713
Portfolio turnover rate^G	47%	18%	57%	128%	25%

^A For the year ended February 29.

^B Calculated based on average shares outstanding during the period.

^C Total returns for periods of less than one year are not annualized.

^D Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^E Fees and expenses of any underlying mutual funds or exchange-traded funds (ETFs) are not included in the Fund's expense ratio. The Fund indirectly bears its proportionate share of these expenses. For additional expense information related to investments in Fidelity Central Funds, please refer to the "Investments in Fidelity Central Funds" note found in the Notes to Financial Statements section of the most recent Annual or Semi-Annual report.

^F Expense ratios reflect operating expenses of the class. Expenses before reductions do not reflect amounts reimbursed, waived, or reduced through arrangements with the investment advisor, brokerage services, or other offset arrangements, if applicable, and do not represent the amount paid by the class during periods when reimbursements, waivers or reductions occur.

^G Amount does not include the portfolio activity of any underlying mutual funds or exchange-traded funds (ETFs).

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended February 28, 2021

1. Organization.

Fidelity SAI Long-Term Treasury Bond Index Fund (the Fund) is a fund of Fidelity Salem Street Trust (the Trust) and is authorized to issue an unlimited number of shares. Shares are offered exclusively to certain clients of Fidelity Management & Research Company LLC (FMR) or its affiliates. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Massachusetts business trust.

2. Investments in Fidelity Central Funds.

The Fund invests in Fidelity Central Funds, which are open-end investment companies generally available only to other investment companies and accounts managed by the investment adviser and its affiliates. The Fund's Schedule of Investments lists each of the Fidelity Central Funds held as of period end, if any, as an investment of the Fund, but does not include the underlying holdings of each Fidelity Central Fund. As an Investing Fund, the Fund indirectly bears its proportionate share of the expenses of the underlying Fidelity Central Funds.

The Money Market Central Funds seek preservation of capital and current income and are managed by the investment adviser. Annualized expenses of the Money Market Central Funds as of their most recent shareholder report date ranged from less than .005% to .01%.

A complete unaudited list of holdings for each Fidelity Central Fund is available upon request or at the Securities and Exchange Commission (the SEC) website at www.sec.gov. In addition, the financial statements of the Fidelity Central Funds, which are not covered by the Fund's Report of Independent Registered Public Accounting Firm, are available on the SEC website or upon request.

3. Significant Accounting Policies.

The Fund is an investment company and applies the accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies. The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP), which require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from those estimates. Subsequent events, if any, through the date that the financial statements were issued have been evaluated in the preparation of the financial statements. The following summarizes the significant accounting policies of the Fund:

Investment Valuation. Investments are valued as of 4:00 p.m. Eastern time on the last calendar day of the period. The Board of Trustees (the Board) has delegated the day to day responsibility for the valuation of the Fund's investments to the Fair Value Committee (the Committee) established by the Fund's investment adviser. In accordance with valuation policies and procedures approved by the Board, the Fund attempts to obtain prices from one or more third party pricing vendors or brokers to value its investments. When current market prices, quotations or currency exchange rates are not readily available or reliable, investments will be fair valued in good faith by the Committee, in accordance with procedures adopted by the Board. Factors used in determining fair value vary by investment type and may include market or investment specific events, changes in interest rates and credit quality. The frequency with which these procedures are used cannot be predicted and they may be utilized to a significant extent. The Committee oversee the Fund's valuation policies and procedures and reports to the Board on the Committee's activities and fair value determinations. The Board monitors the appropriateness of the procedures used in valuing the Fund's investments and ratifies the fair value determinations of the Committee.

The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Valuation techniques used to value the Fund's investments by major category are as follows:

Debt securities, including restricted securities, are valued based on evaluated prices received from third party pricing vendors or from brokers who make markets in such securities. U.S. government and government agency obligations are valued by pricing vendors who utilize matrix pricing which considers prepayment speed assumptions, attributes of the collateral, yield or price of bonds of comparable quality, coupon, maturity and type or by broker-supplied prices. When independent prices are unavailable or unreliable, debt securities may be valued utilizing pricing methodologies which consider similar factors that would be used by third party pricing vendors. Debt securities are generally categorized as Level 2 in the hierarchy but may be Level 3 depending on the circumstances.

Investments in open-end mutual funds, including the Fidelity Central Funds, are valued at their closing net asset value (NAV) each business day and are categorized as Level 1 in the hierarchy.

Changes in valuation techniques may result in transfers in or out of an assigned level within the disclosure hierarchy. The aggregate value of investments by input level as of February 28, 2021 is included at the end of the Fund's Schedule of Investments.

Investment Transactions and Income. For financial reporting purposes, the Fund's investment holdings and NAV include trades executed through the end of the last business day of the period. The NAV per share for processing shareholder transactions is calculated as of the close of business of the New York Stock Exchange (NYSE), normally 4:00 p.m. Eastern time and includes trades executed through the end of the prior business day. Gains and losses on securities sold are determined on the basis of identified cost. Income and capital gain distributions from Fidelity Central Funds, if any, are recorded on the ex-dividend date. Interest income is accrued as earned and includes coupon interest and amortization of premium and accretion of discount on debt securities as applicable.

Expenses. Expenses directly attributable to a fund are charged to that fund. Expenses attributable to more than one fund are allocated among the respective funds on the basis of relative net assets or other appropriate methods. Expense estimates are accrued in the period to which they relate and adjustments are made when actual amounts are known.

Income Tax Information and Distributions to Shareholders. Each year, the Fund intends to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code, including distributing substantially all of its taxable income and realized gains. As a result, no provision for U.S. Federal income taxes is required. As of February 28, 2021, the Fund did not have any unrecognized tax benefits in the financial statements; nor is the Fund aware of any tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. The Fund files a U.S. federal tax return, in addition to state and local tax returns as required. The Fund's federal income tax returns are subject to examination by the Internal Revenue Service (IRS) for a period of three fiscal years after they are filed. State and local tax returns may be subject to examination for an additional fiscal year depending on the jurisdiction.

Distributions are declared and recorded daily and paid monthly from net investment income. Distributions from realized gains, if any, are declared and recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. In addition, the Fund claimed a portion of the payment made to redeeming shareholders as a distribution for income tax purposes.

Capital accounts within the financial statements are adjusted for permanent book-tax differences. These adjustments have no impact on net assets or the results of operations. Capital accounts are not adjusted for temporary book-tax differences which will reverse in a subsequent period.

Book-tax differences are primarily due to market discount, capital loss carryforwards and losses deferred due to wash sales.

As of period end, the cost and unrealized appreciation (depreciation) in securities, and derivatives if applicable, for federal income tax purposes were as follows:

Gross unrealized appreciation	$20,655,588
Gross unrealized depreciation	(62,059,442)
Net unrealized appreciation (depreciation)	$(41,403,854)
Tax Cost	$1,219,880,324

The tax-based components of distributable earnings as of period end were as follows:

Undistributed ordinary income	$518,201
Undistributed long-term capital gain	$2,219,234
Net unrealized appreciation (depreciation) on securities and other investments	$(41,403,854)

The tax character of distributions paid was as follows:

	February 28, 2021	February 29, 2020
Ordinary Income	$56,878,176	$ 7,507,765
Long-term Capital Gains	7,314,462	–
Total	$64,192,638	$ 7,507,765

Capital loss carryforwards are only available to offset future capital gains of the Fund to the extent provided by regulations and may be limited. The capital loss carryforward information presented below, including any applicable limitation, is estimated as of fiscal period end and is subject to adjustment.

No expiration
Short-term	$(13,221,786)
Long-term	(9,440,961)
Total capital loss carryforward	$(22,662,747)

Due to large subscriptions in a prior period, $22,662,747 of capital losses that will be available to offset future capital gains of the Fund will be limited to approximately $3,662,975 per year.

4. Fees and Other Transactions with Affiliates.

Interfund Trades. Funds may purchase from or sell securities to other Fidelity Funds under procedures adopted by the Board. The procedures have been designed to ensure these interfund trades are executed in accordance with Rule 17a-7 of the 1940 Act.

5. Committed Line of Credit.

Certain Funds participate with other funds managed by the investment adviser or an affiliate in a $4.25 billion credit facility (the "line of credit") to be utilized for temporary or emergency purposes to fund shareholder redemptions or for other short-term liquidity purposes. The participating funds have agreed to pay commitment fees on their pro-rata portion of the line of credit, which are reflected in Miscellaneous expenses on the Statement of Operations, and are listed below.

	Amount
Fidelity SAI Long-Term Treasury Bond Index Fund	$2,334

During the period, there were no borrowings on this line of credit.

6. Security Lending.

Funds lend portfolio securities from time to time in order to earn additional income. Lending agents are used, including National Financial Services (NFS), an affiliate of the investment adviser. Pursuant to a securities lending agreement, NFS will receive a fee, which is capped at 9.9% of a fund's daily lending revenue, for its services as lending agent. A fund may lend securities to certain qualified borrowers, including NFS. On the settlement date of the loan, a fund receives collateral (in the form of U.S. Treasury obligations, letters of credit and/or cash) against the loaned securities and maintains collateral in an amount not less than 100% of the market value of the loaned securities during the period of the loan. The market value of the loaned securities is determined at the close of business of a fund and any additional required collateral is delivered to a fund on the next business day. A fund or borrower may terminate the loan at any time, and if the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund may apply collateral received from the borrower against the obligation. A fund may experience delays and costs in recovering the securities loaned. Any cash collateral received is invested in the Fidelity Securities Lending Cash Central Fund. Any loaned securities are identified as such in the Schedule of Investments, and the value of loaned securities and cash collateral at period end, as applicable, are presented in the Statement of Assets and Liabilities. Security lending income represents the income earned on investing cash collateral, less rebates paid to borrowers and any lending agent fees associated with the loan, plus any premium payments received for lending certain types of securities. Security lending income is presented in the Statement of Operations as a component of income from Fidelity Central Funds. Affiliated security lending activity, if any, was as follows:

	Total Security Lending Income Fees Paid to NFS	Security Lending Income From Securities Loaned to NFS	Value of Securities Loaned to NFS at Period End
Fidelity SAI Long-Term Treasury Bond Index Fund	$769	$–	$–

7. Expense Reductions.

The investment adviser contractually agreed to reimburse the Fund to the extent annual operating expenses exceeded .03% of average net assets. This reimbursement will remain in place through June 30, 2022. Some expenses, for example the compensation of the independent Trustees, and certain miscellaneous expenses such as proxy and shareholder meeting expenses, are excluded from this reimbursement. During the period this reimbursement reduced the Fund's expenses by $208,335.

In addition, through arrangements with the Fund's custodian, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses by $201.

8. Other.

The Fund's organizational documents provide former and current trustees and officers with a limited indemnification against liabilities arising in connection with the performance of their duties to the Fund. In the normal course of business, the Fund may also enter into contracts that provide general indemnifications. The Fund's maximum exposure under these arrangements is unknown as this would be dependent on future claims that may be made against the Fund. The risk of material loss from such claims is considered remote.

At the end of the period, Strategic Advisers Fidelity Core Income Fund were the owners of record of approximately 100% of the total outstanding shares of the Fund.

9. Coronavirus (COVID-19) Pandemic.

An outbreak of COVID-19 first detected in China during December 2019 has since spread globally and was declared a pandemic by the World Health Organization during March 2020. Developments that disrupt global economies and financial markets, such as the COVID-19 pandemic, may magnify factors that affect the Fund's performance.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Salem Street Trust and Shareholders of Fidelity SAI Long-Term Treasury Bond Index Fund

Opinion on the Financial Statements and Financial Highlights

We have audited the accompanying statement of assets and liabilities of Fidelity SAI Long-Term Treasury Bond Index Fund (the "Fund"), a fund of Fidelity Salem Street Trust, including the schedule of investments, as of February 28, 2021, the related statement of operations for the year then ended, the statement 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 February 28, 2021, 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 February 28, 2021, by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

April 13, 2021

We have served as the auditor of one or more of the Fidelity investment companies since 1999.

Trustees and Officers

The Trustees, Members of the Advisory Board (if any), and officers of the trust and fund, as applicable, are listed below. The Board of Trustees governs the fund and is responsible for protecting the interests of shareholders. The Trustees are experienced executives who meet periodically throughout the year to oversee the fund's activities, review contractual arrangements with companies that provide services to the fund, oversee management of the risks associated with such activities and contractual arrangements, and review the fund's performance. Except for Jonathan Chiel, each of the Trustees oversees 282 funds. Mr. Chiel oversees 176 funds.

The Trustees hold office without limit in time except that (a) any Trustee may resign; (b) any Trustee may be removed by written instrument, signed by at least two-thirds of the number of Trustees prior to such removal; (c) any Trustee who requests to be retired or who has become incapacitated by illness or injury may be retired by written instrument signed by a majority of the other Trustees; and (d) any Trustee may be removed at any special meeting of shareholders by a two-thirds vote of the outstanding voting securities of the trust. Each Trustee who is not an interested person (as defined in the 1940 Act) of the trust and the fund is referred to herein as an Independent Trustee. Each Independent Trustee shall retire not later than the last day of the calendar year in which his or her 75th birthday occurs. The Independent Trustees may waive this mandatory retirement age policy with respect to individual Trustees. Officers and Advisory Board Members hold office without limit in time, except that any officer or Advisory Board Member may resign or may be removed by a vote of a majority of the Trustees at any regular meeting or any special meeting of the Trustees. Except as indicated, each individual has held the office shown or other offices in the same company for the past five years.

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-3455.

Experience, Skills, Attributes, and Qualifications of the Trustees. The Governance and Nominating Committee has adopted a statement of policy that describes the experience, qualifications, attributes, and skills that are necessary and desirable for potential Independent Trustee candidates (Statement of Policy). The Board believes that each Trustee satisfied at the time he or she was initially elected or appointed a Trustee, and continues to satisfy, the standards contemplated by the Statement of Policy. The Governance and Nominating Committee also engages professional search firms to help identify potential Independent Trustee candidates who have the experience, qualifications, attributes, and skills consistent with the Statement of Policy. From time to time, additional criteria based on the composition and skills of the current Independent Trustees, as well as experience or skills that may be appropriate in light of future changes to board composition, business conditions, and regulatory or other developments, have also been considered by the professional search firms and the Governance and Nominating Committee. In addition, the Board takes into account the Trustees' commitment and participation in Board and committee meetings, as well as their leadership of standing and ad hoc committees throughout their tenure.

In determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, qualifications, attributes, and skills, which allow the Board to operate effectively in governing the fund and protecting the interests of shareholders. Information about the specific experience, skills, attributes, and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a trustee of the fund, is provided below.

Board Structure and Oversight Function. Abigail P. Johnson is an interested person and currently serves as Chairman. The Trustees have determined that an interested Chairman is appropriate and benefits shareholders because an interested Chairman has a personal and professional stake in the quality and continuity of services provided to the fund. Independent Trustees exercise their informed business judgment to appoint an individual of their choosing to serve as Chairman, regardless of whether the Trustee happens to be independent or a member of management. The Independent Trustees have determined that they can act independently and effectively without having an Independent Trustee serve as Chairman and that a key structural component for assuring that they are in a position to do so is for the Independent Trustees to constitute a substantial majority for the Board. The Independent Trustees also regularly meet in executive session. Arthur E. Johnson serves as Chairman of the Independent Trustees and as such (i) acts as a liaison between the Independent Trustees and management with respect to matters important to the Independent Trustees and (ii) with management prepares agendas for Board meetings.

Fidelity^® funds are overseen by different Boards of Trustees. The fund's Board oversees Fidelity's investment-grade bond, money market, asset allocation and certain equity funds, and other Boards oversee Fidelity's high income and other equity funds. The asset allocation funds may invest in Fidelity^® funds that are overseen by such other Boards. The use of separate Boards, each with its own committee structure, allows the Trustees of each group of Fidelity^® funds to focus on the unique issues of the funds they oversee, including common research, investment, and operational issues. On occasion, the separate Boards establish joint committees to address issues of overlapping consequences for the Fidelity^® funds overseen by each Board.

The Trustees operate using a system of committees to facilitate the timely and efficient consideration of all matters of importance to the Trustees, the fund, and fund shareholders and to facilitate compliance with legal and regulatory requirements and oversight of the fund's activities and associated risks. The Board, acting through its committees, has charged FMR and its affiliates with (i) identifying events or circumstances the occurrence of which could have demonstrably adverse effects on the fund's business and/or reputation; (ii) implementing processes and controls to lessen the possibility that such events or circumstances occur or to mitigate the effects of such events or circumstances if they do occur; and (iii) creating and maintaining a system designed to evaluate continuously business and market conditions in order to facilitate the identification and implementation processes described in (i) and (ii) above. Because the day-to-day operations and activities of the fund are carried out by or through FMR, its affiliates, and other service providers, the fund's exposure to risks is mitigated but not eliminated by the processes overseen by the Trustees. While each of the Board's committees has responsibility for overseeing different aspects of the fund's activities, oversight is exercised primarily through the Operations and Audit Committees. In addition, an ad hoc Board committee of Independent Trustees has worked with FMR to enhance the Board's oversight of investment and financial risks, legal and regulatory risks, technology risks, and operational risks, including the development of additional risk reporting to the Board. Appropriate personnel, including but not limited to the fund's Chief Compliance Officer (CCO), FMR's internal auditor, the independent accountants, the fund's Treasurer and portfolio management personnel, make periodic reports to the Board's committees, as appropriate, including an annual review of Fidelity's risk management program for the Fidelity^® funds. The responsibilities of each standing committee, including their oversight responsibilities, are described further under "Standing Committees of the Trustees."

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Jonathan Chiel (1957)

Year of Election or Appointment: 2016

Trustee

Mr. Chiel also serves as Trustee of other Fidelity^® funds. Mr. Chiel is Executive Vice President and General Counsel for FMR LLC (diversified financial services company, 2012-present). Previously, Mr. Chiel served as general counsel (2004-2012) and senior vice president and deputy general counsel (2000-2004) for John Hancock Financial Services; a partner with Choate, Hall & Stewart (1996-2000) (law firm); and an Assistant United States Attorney for the United States Attorney’s Office of the District of Massachusetts (1986-95), including Chief of the Criminal Division (1993-1995). Mr. Chiel is a director on the boards of the Boston Bar Foundation and the Maimonides School.

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Ms. Johnson also serves as Trustee of other Fidelity^® funds. Ms. Johnson serves as Chairman (2016-present), Chief Executive Officer (2014-present), and Director (2007-present) of FMR LLC (diversified financial services company), President of Fidelity Financial Services (2012-present) and President of Personal, Workplace and Institutional Services (2005-present). Ms. Johnson is Chairman and Director of Fidelity Management & Research Company LLC (investment adviser firm, 2011-present). Previously, Ms. Johnson served as Chairman and Director of FMR Co., Inc. (investment adviser firm, 2011-2019), Vice Chairman (2007-2016) and President (2013-2016) of FMR LLC, President and a Director of Fidelity Management & Research Company (2001-2005), a Trustee of other investment companies advised by Fidelity Management & Research Company, Fidelity Investments Money Management, Inc. (investment adviser firm), and FMR Co., Inc. (2001-2005), Senior Vice President of the Fidelity^® funds (2001-2005), and managed a number of Fidelity^® funds. Ms. Abigail P. Johnson and Mr. Arthur E. Johnson are not related.

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

Ms. McAuliffe also serves as Trustee of other Fidelity^® funds. Previously, Ms. McAuliffe served as Co-Head of Fixed Income of Fidelity Investments Limited (now known as FIL Limited (FIL)) (diversified financial services company), Director of Research for FIL’s credit and quantitative teams in London, Hong Kong and Tokyo and Director of Research for taxable and municipal bonds at Fidelity Investments Money Management, Inc. Ms. McAuliffe previously served as a member of the Advisory Board of certain Fidelity^® funds (2016). Ms. McAuliffe was previously a lawyer at Ropes & Gray LLP and currently serves as director or trustee of several not-for-profit entities.

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

+ The information includes the Trustee's principal occupation during the last five years and other information relating to the experience, attributes, and skills relevant to the Trustee's qualifications to serve as a Trustee, which led to the conclusion that the Trustee should serve as a Trustee for the fund.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ms. Acton also serves as Trustee of other Fidelity^® funds. Prior to her retirement, Ms. Acton served as Executive Vice President, Finance (2011-2012), Executive Vice President, Chief Financial Officer (2002-2011) and Treasurer (2004-2005) of Comerica Incorporated (financial services). Prior to joining Comerica, Ms. Acton held a variety of positions at Ford Motor Company (1983-2002), including Vice President and Treasurer (2000-2002) and Executive Vice President and Chief Financial Officer of Ford Motor Credit Company (1998-2000). Ms. Acton currently serves as a member of the Board and Audit and Finance Committees of Beazer Homes USA, Inc. (homebuilding, 2012-present). Ms. Acton previously served as a member of the Advisory Board of certain Fidelity^® funds (2013-2016).

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

General Dunwoody also serves as Trustee of other Fidelity^® funds. General Dunwoody (United States Army, Retired) was the first woman in U.S. military history to achieve the rank of four-star general and prior to her retirement in 2012 held a variety of positions within the U.S. Army, including Commanding General, U.S. Army Material Command (2008-2012). General Dunwoody currently serves as President of First to Four LLC (leadership and mentoring services, 2012-present), a member of the Board and Nomination and Corporate Governance Committees of Kforce Inc. (professional staffing services, 2016-present) and a member of the Board of Automattic Inc. (software engineering, 2018-present). Previously, General Dunwoody served as a member of the Advisory Board and Nominating and Corporate Governance Committee of L3 Technologies, Inc. (communication, electronic, sensor and aerospace systems, 2013-2019) and a member of the Board and Audit and Sustainability and Corporate Responsibility Committees of Republic Services, Inc. (waste collection, disposal and recycling, 2013-2016). Ms. Dunwoody also serves on several boards for non-profit organizations, including as a member of the Board, Chair of the Nomination and Governance Committee and a member of the Audit Committee of Logistics Management Institute (consulting non-profit, 2012-present), a member of the Council of Trustees for the Association of the United States Army (advocacy non-profit, 2013-present), a member of the Board of Florida Institute of Technology (2015-present) and a member of the Board of ThanksUSA (military family education non-profit, 2014-present). General Dunwoody previously served as a member of the Advisory Board of certain Fidelity^® funds (2018).

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Mr. Engler also serves as Trustee of other Fidelity^® funds. Previously, Mr. Engler served as Governor of Michigan (1991-2003), President of the Business Roundtable (2011-2017) and interim President of Michigan State University (2018-2019). Mr. Engler currently serves as a member of the Board of K12 Inc. (technology-based education company, 2012-present). Previously, Mr. Engler served as a member of the Board of Universal Forest Products (manufacturer and distributor of wood and wood-alternative products, 2003-2019) and Trustee of The Munder Funds (2003-2014). Mr. Engler previously served as a member of the Advisory Board of certain Fidelity^® funds (2014-2016).

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Mr. Gartland also serves as Trustee of other Fidelity^® funds. Prior to his retirement, Mr. Gartland held a variety of positions at Morgan Stanley (financial services, 1979-2007), including Managing Director (1987-2007) and Chase Manhattan Bank (1975-1978). Mr. Gartland previously served as Chairman and an investor in Gartland & Mellina Group Corp. (consulting, 2009-2019), as a member of the Board of National Securities Clearing Corporation (1993-1996) and as Chairman of TradeWeb (2003-2004).

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Mr. Johnson also serves as Trustee of other Fidelity^® funds. Prior to his retirement, Mr. Johnson served as Senior Vice President of Corporate Strategic Development of Lockheed Martin Corporation (defense contractor, 1999-2009). Mr. Johnson currently serves as a member of the Board of Booz Allen Hamilton (management consulting, 2011-present). Mr. Johnson previously served as a member of the Board of Eaton Corporation plc (diversified power management, 2009-2019) and a member of the Board of AGL Resources, Inc. (holding company, 2002-2016). Mr. Johnson previously served as Vice Chairman (2015-2018) of the Independent Trustees of certain Fidelity^® funds. Mr. Arthur E. Johnson is not related to Ms. Abigail P. Johnson.

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Mr. Kenneally also serves as Trustee of other Fidelity^® funds. Prior to his retirement, Mr. Kenneally served as Chairman and Global Chief Executive Officer of Credit Suisse Asset Management and Executive Vice President and Chief Investment Officer of Bank of America Corporation. Earlier roles at Bank of America included Director of Research, Senior Portfolio Manager for various institutional equity accounts and mutual funds and Portfolio Manager for a number of institutional fixed-income clients. Mr. Kenneally began his career as a Research Analyst in 1983 and was awarded the Chartered Financial Analyst (CFA) designation in 1991.

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Ms. Knowles also serves as Trustee of other Fidelity^® funds. Prior to her retirement, Ms. Knowles held several positions at Atlantic Richfield Company (diversified energy), including Executive Vice President and Chief Financial Officer (1996-2000), Senior Vice President (1993-1996) and President of ARCO Transportation Company (pipeline and tanker operations, 1993-1996). Ms. Knowles currently serves as a member of the Board of McKesson Corporation (healthcare service, since 2002), a member of the Board of the Santa Catalina Island Company (real estate, 2009-present), a member of the Investment Company Institute Board of Governors and a member of the Governing Council of the Independent Directors Council (2014-present). Ms. Knowles also serves as a member of the Advisory Board for the School of Engineering of the University of Southern California. Ms. Knowles previously served as Chairman (2015-2018) and Vice Chairman (2012-2015) of the Independent Trustees of certain Fidelity^® funds.

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Mr. Murray also serves as Trustee of other Fidelity^® funds. Previously, Mr. Murray served as Co-Chief Executive Officer (2013-2016), President (2006-2013) and Vice Chairman (2013-2020) of Meijer, Inc. Mr. Murray serves as a member of the Board and Nuclear Review and Public Policy and Responsibility Committees of DTE Energy Company (diversified energy company, 2009-present) and a member of the Board and Audit Committee and Chairman of the Nominating and Corporate Governance Committee of Universal Forest Products, Inc. (manufacturer and distributor of wood and wood-alternative products, 2004-2016). Mr. Murray previously served as a member of the Board of Spectrum Health (not-for-profit health system, 2015-2019). Mr. Murray also serves as a member of the Board of many community and professional organizations. Mr. Murray previously served as a member of the Advisory Board of certain Fidelity^® funds (2016).

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

Mr. Burke also serves as Chief Financial Officer of other funds. Mr. Burke serves as Head of Investment Operations for Fidelity Fund and Investment Operations (2018-present) and is an employee of Fidelity Investments (1998-present). Previously Mr. Burke served as head of Asset Management Investment Operations (2012-2018).

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Mr. Davis also serves as Assistant Treasurer of other funds. Mr. Davis serves as Assistant Treasurer of FMR Capital, Inc. (2017-present) and is an employee of Fidelity Investments. Previously, Mr. Davis served as Vice President and Associate General Counsel of FMR LLC (diversified financial services company, 2003-2010).

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Ms. Del Prato also serves as an officer of other funds. Ms. Del Prato is an employee of Fidelity Investments (2017-present). Previously, Ms. Del Prato served as President and Treasurer of The North Carolina Capital Management Trust: Cash Portfolio and Term Portfolio (2018-2020). Prior to joining Fidelity Investments, Ms. Del Prato served as a Managing Director and Treasurer of the JPMorgan Mutual Funds (2014-2017). Prior to JPMorgan, Ms. Del Prato served as a partner at Cohen Fund Audit Services (accounting firm, 2012-2013) and KPMG LLP (accounting firm, 2004-2012).

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Mr. Hogan also serves as an officer of other funds. Mr. Hogan serves as Assistant Treasurer of FMR Capital, Inc. (2017-present) and is an employee of Fidelity Investments (2005-present). Previously, Mr. Hogan served as Deputy Treasurer of certain Fidelity^® funds (2016-2020) and Assistant Treasurer of certain Fidelity^® funds (2016-2018).

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Ms. Lo Bessette also serves as an officer of other funds. Ms. Lo Bessette serves as CLO, Secretary, and Senior Vice President of Fidelity Management & Research Company LLC (investment adviser firm, 2019-present); and CLO of Fidelity Management & Research (Hong Kong) Limited, FMR Investment Management (UK) Limited, and Fidelity Management & Research (Japan) Limited (investment adviser firms, 2019-present). She is a Senior Vice President and Deputy General Counsel of FMR LLC (diversified financial services company, 2019-present), and is an employee of Fidelity Investments. Previously, Ms. Lo Bessette served as CLO, Secretary, and Senior Vice President of FMR Co., Inc. (investment adviser firm, 2019); Secretary of Fidelity SelectCo, LLC and Fidelity Investments Money Management, Inc. (investment adviser firms, 2019). Prior to joining Fidelity Investments, Ms. Lo Bessette was Executive Vice President, General Counsel (2016-2019) and Senior Vice President, Deputy General Counsel (2015-2016) of OppenheimerFunds (investment management company) and Deputy Chief Legal Officer (2013-2015) of Jennison Associates LLC (investment adviser firm).

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Mr. Maher also serves as an officer of other funds. Mr. Maher serves as Assistant Treasurer of FMR Capital, Inc. (2017-present), and is an employee of Fidelity Investments (2008-present). Previously, Mr. Maher served as Assistant Treasurer of certain funds (2013-2020); Vice President of Asset Management Compliance (2013), Vice President of the Program Management Group of FMR (investment adviser firm, 2010-2013), and Vice President of Valuation Oversight (2008-2010).

Jamie Pagliocco (1964)

Year of Election or Appointment: 2020

Vice President

Mr. Pagliocco also serves as Vice President of other funds. Mr. Pagliocco serves as President of Fixed Income (2020-present), and is an employee of Fidelity Investments (2001-present). Previously, Mr. Pagliocco served as Co-Chief Investment Officer – Bond (2017-2020), Global Head of Bond Trading (2016-2019), and as a portfolio manager.

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Mr. Robins also serves as an officer of other funds. Mr. Robins serves as Compliance Officer of Fidelity Management & Research Company LLC (investment adviser firm, 2016-present) and is an employee of Fidelity Investments (2004-present). Previously, Mr. Robins served as Compliance Officer of FMR Co., Inc. (investment adviser firm, 2016-2019), as Executive Vice President of Fidelity Investments Money Management, Inc. (investment adviser firm, 2013-2016) and served in other fund officer roles.

Brett Segaloff (1972)

Year of Election or Appointment: 2021

Anti-Money Laundering (AML) Officer

Mr. Segaloff also serves as an AML Officer of other funds and other related entities. He is Director, Anti-Money Laundering (2007-present) of FMR LLC (diversified financial services company) and is an employee of Fidelity Investments (1996-present).

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Ms. Smith also serves as an officer of other funds. Ms. Smith serves as Assistant Treasurer of FMR Capital, Inc. (2017-present), is an employee of Fidelity Investments (2009-present), and has served in other fund officer roles. Prior to joining Fidelity Investments, Ms. Smith served as Senior Audit Manager of Ernst & Young LLP (accounting firm, 1996-2009). Previously, Ms. Smith served as Assistant Treasurer (2013-2019) and Deputy Treasurer (2013-2016) of certain Fidelity^® funds.

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Mr. Spector also serves as an officer of other funds. Mr. Spector serves as Assistant Treasurer of FMR Capital, Inc. (2017-present) and is an employee of Fidelity Investments (2016-present). Prior to joining Fidelity Investments, Mr. Spector served as Director at the Siegfried Group (accounting firm, 2013-2016), and prior to Siegfried Group as audit senior manager at Deloitte & Touche LLP (accounting firm, 2005-2013).

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

As a shareholder, you incur two types of costs: (1) transaction costs, which may include sales charges (loads) on purchase payments or redemption proceeds, as applicable and (2) ongoing costs, which generally include management fees, distribution and/or service (12b-1) fees and other Fund expenses. This Example is intended to help you understand your ongoing costs (in dollars) of investing in a fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (September 1, 2020 to February 28, 2021).

Actual Expenses

The first line of the accompanying table provides information about actual account values and actual expenses. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000.00 (for example, an $8,600 account value divided by $1,000.00 = 8.6), then multiply the result by the number in the first line for a class/Fund under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period. If any fund is a shareholder of any underlying mutual funds or exchange-traded funds (ETFs) (the Underlying Funds), such fund indirectly bears its proportional share of the expenses of the Underlying Funds in addition to the direct expenses incurred presented in the table. These fees and expenses are not included in the annualized expense ratio used to calculate the expense estimate in the table below.

Hypothetical Example for Comparison Purposes

The second line of the accompanying table provides information about hypothetical account values and hypothetical expenses based on the actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds. If any fund is a shareholder of any Underlying Funds, such fund indirectly bears its proportional share of the expenses of the Underlying Funds in addition to the direct expenses as presented in the table. These fees and expenses are not included in the annualized expense ratio used to calculate the expense estimate in the table below.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transaction costs. Therefore, the second line of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Annualized Expense Ratio-^A	Beginning Account Value September 1, 2020	Ending Account Value February 28, 2021	Expenses Paid During Period-^B September 1, 2020 to February 28, 2021
Fidelity SAI Long-Term Treasury Bond Index Fund	.03%
Actual		$1,000.00	$888.40	$.14
Hypothetical-^C		$1,000.00	$1,024.65	$.15

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^B Expenses are equal to the annualized expense ratio, multiplied by the average account value over the period, multiplied by 181/ 365 (to reflect the one-half year period). The fees and expenses of any Underlying Funds are not included in each annualized expense ratio.

^C 5% return per year before expenses

Distributions (Unaudited)

The Board of Trustees of Fidelity SAI Long-Term Treasury Bond Index Fund voted to pay on April 12, 2021, to shareholders of record at the opening of business on April 9, 2021, a distribution of $0.027 per share derived from capital gains realized from sales of portfolio securities.

The fund hereby designates as a capital gain dividend with respect to the taxable year ended February 28, 2021, $9,533,696, or, if subsequently determined to be different, the net capital gain of such year.

A total of 99.95% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $18,699,969 of distributions paid in the calendar year 2020 as qualifying to be taxed as section 163(j) interest dividends.

The fund will notify shareholders in January 2022 of amounts for use in preparing 2021 income tax returns.

Board Approval of Investment Advisory Contracts and Management Fees

Fidelity SAI Long-Term Treasury Bond Index Fund

Each year, the Board of Trustees, including the Independent Trustees (together, the Board), votes on the renewal of the management contract with Fidelity Management & Research Company LLC (FMR) and the sub-advisory agreements (together, the Advisory Contracts) for the fund. FMR and the sub-advisers are referred to herein as the Investment Advisers. The Board, assisted by the advice of fund counsel and Independent Trustees' counsel, requests and considers a broad range of information relevant to the renewal of the Advisory Contracts throughout the year.

The Board meets regularly and, at each of its meetings, covers an extensive agenda of topics and materials and considers factors that are relevant to its annual consideration of the renewal of the fund's Advisory Contracts, including the services and support provided to the fund and its shareholders. The Board has established four standing committees (Committees) — Operations, Audit, Fair Valuation, and Governance and Nominating — each composed of and chaired by Independent Trustees with varying backgrounds, to which the Board has assigned specific subject matter responsibilities in order to enhance effective decision-making by the Board. The Operations Committee, of which all of the Independent Trustees are members, meets regularly throughout the year and considers, among other matters, information specifically related to the annual consideration of the renewal of the fund's Advisory Contracts. The Board, acting directly and through its Committees, requests and receives information concerning the annual consideration of the renewal of the fund's Advisory Contracts. The Board also meets as needed to review matters specifically related to the Board's annual consideration of the renewal of the Advisory Contracts. Members of the Board may also meet with trustees of other Fidelity funds through joint ad hoc committees to discuss certain matters relevant to all of the Fidelity funds.

At its September 2020 meeting, the Board unanimously determined to renew the fund's Advisory Contracts. In reaching its determination, the Board considered all factors it believed relevant, including (i) the nature, extent, and quality of the services provided to the fund and its shareholders (including the investment performance of the fund); (ii) the competitiveness of the fund's management fee and total expense ratio relative to peer funds; (iii) the total costs of the services provided by and the profits realized by Fidelity from its relationships with the fund; and (iv) the extent to which, if any, economies of scale exist and are realized as the fund grows, and whether any economies of scale are appropriately shared with fund shareholders.

In considering whether to renew the Advisory Contracts for the fund, the Board reached a determination, with the assistance of fund counsel and Independent Trustees' counsel and through the exercise of its business judgment, that the renewal of the Advisory Contracts was in the best interests of the fund and its shareholders and that the compensation payable under the Advisory Contracts was fair and reasonable. The Board's decision to renew the Advisory Contracts was not based on any single factor, but rather was based on a comprehensive consideration of all the information provided to the Board at its meetings throughout the year. The Board, in reaching its determination to renew the Advisory Contracts, was aware that shareholders of the fund have a broad range of investment choices available to them, including a wide choice among funds offered by Fidelity's competitors, and that the fund's shareholders, who have the opportunity to review and weigh the disclosure provided by the fund in its prospectus and other public disclosures, have chosen to invest in this fund, which is part of the Fidelity family of funds.

Nature, Extent, and Quality of Services Provided. The Board considered Fidelity's staffing as it relates to the fund, including the backgrounds of investment personnel of Fidelity, and also considered the fund's investment objective, strategies, and related investment philosophy. The Independent Trustees also had discussions with senior management of Fidelity's investment operations and investment groups. The Board considered the structure of the investment personnel compensation program and whether this structure provides appropriate incentives to act in the best interests of the fund. Additionally, the Board considered the portfolio managers' investments, if any, in the funds that they manage.

Resources Dedicated to Investment Management and Support Services. The Board reviewed the general qualifications and capabilities of Fidelity's investment staff, including its size, education, experience, and resources, as well as Fidelity's approach to recruiting, managing, and compensating investment personnel. The Board noted that Fidelity has continued to increase the resources devoted to non-U.S. offices, including expansion of Fidelity's global investment organization. The Board also noted that Fidelity's analysts have extensive resources, tools and capabilities that allow them to conduct sophisticated quantitative and fundamental analysis, as well as credit analysis of issuers, counterparties and guarantors. Further, the Board considered that Fidelity's investment professionals have sufficient access to global information and data so as to provide competitive investment results over time, and that those professionals also have access to sophisticated tools that permit them to assess portfolio construction and risk and performance attribution characteristics continuously, as well as to transmit new information and research conclusions rapidly around the world. Additionally, in its deliberations, the Board considered Fidelity's trading, risk management, compliance, and technology and operations capabilities and resources, which are integral parts of the investment management process. The Board also considered Fidelity's investments in business continuity planning, and its success in continuously providing services to the fund notwithstanding the severe disruptions caused by the COVID-19 pandemic.

Shareholder and Administrative Services. The Board considered (i) the nature, extent, quality, and cost of advisory, administrative, and shareholder services performed by the Investment Advisers and their affiliates under the Advisory Contracts and under separate agreements covering transfer agency, pricing and bookkeeping, and securities lending services for the fund; (ii) the nature and extent of the supervision of third party service providers, principally custodians, subcustodians, and pricing vendors; and (iii) the resources devoted to, and the record of compliance with, the fund's compliance policies and procedures.

The Board noted that the growth of fund assets over time across the complex allows Fidelity to reinvest in the development of services designed to enhance the value and convenience of the Fidelity funds as investment vehicles. These services include 24-hour access to account information and market information over the Internet and through telephone representatives, investor education materials and asset allocation tools, and the expanded availability of Fidelity Investor Centers.

Investment in a Large Fund Family. The Board considered the benefits to shareholders of investing in a Fidelity fund, including the benefits of investing in a fund that is part of a large family of funds offering a variety of investment disciplines and providing a large variety of mutual fund investor services. The Board noted that Fidelity had taken, or had made recommendations that resulted in the Fidelity funds taking, a number of actions over the previous year that benefited particular funds, including: (i) continuing to dedicate additional resources to Fidelity's investment research process, which includes meetings with management of issuers of securities in which the funds invest, and to the support of the senior management team that oversees asset management; (ii) continuing efforts to enhance Fidelity's global research capabilities; (iii) launching new funds and ETFs with innovative structures, strategies and pricing and making other enhancements to meet client needs; (iv) launching new share classes of existing funds; (v) eliminating purchase minimums and broadening eligibility requirements for certain funds and share classes; (vi) reducing management fees and total expenses for certain target date funds or classes and index funds; (vii) lowering expenses for certain funds and classes by implementing or lowering expense caps; (viii) rationalizing product lines and gaining increased efficiencies from fund mergers, liquidations, and share class consolidations; (ix) continuing to develop, acquire and implement systems and technology to improve services to the funds and shareholders, strengthen information security, and increase efficiency; and (x) continuing to implement enhancements to further strengthen Fidelity's product line to increase investors' probability of success in achieving their investment goals, including retirement income goals.

The Board took into account discussions that occur at Board meetings throughout the year with representatives of the Investment Advisers about fund investment performance. In this regard the Board noted that as part of regularly scheduled fund reviews and other reports to the Board on fund performance, the Board considers annualized return information for the fund for different time periods, measured against the securities market index the fund seeks to track and an appropriate peer group of funds with similar objectives (peer group). The Board also periodically considers the fund's tracking error versus its benchmark index. In its evaluation of fund investment performance at meetings throughout the year, the Board gave particular attention to information indicating underperformance of certain Fidelity funds for specific time periods and discussed with the Investment Advisers the reasons for such underperformance.

In addition to reviewing absolute and relative fund performance, the Independent Trustees periodically consider the appropriateness of fund performance metrics in evaluating the results achieved. In general, the Independent Trustees believe that an index fund's performance should be evaluated based on gross performance (before fees and expenses but after transaction costs) compared to a fund's benchmark index, over appropriate time periods, taking into account relevant factors including the following: general market conditions; the characteristics of the fund's benchmark index; the extent to which statistical sampling is employed; and fund cash flows and other factors. The Independent Trustees generally give greater weight to fund performance over longer time periods than over shorter time periods. Depending on the circumstances, the Independent Trustees may be satisfied with a fund's performance notwithstanding that it lags its benchmark index for certain periods.

The Independent Trustees recognize that shareholders evaluate performance on a net basis (after fees and expenses) over their own holding periods, for which one-, three-, and five-year periods are often used as a proxy. For this reason, the performance information reviewed by the Board also included net cumulative calendar year total return information for the fund and its benchmark index and peer group for the most recent one- and three-year periods. The Independent Trustees recognize that shareholders who are not investing through a tax-advantaged retirement account also consider tax consequences in evaluating performance.

Based on its review, the Board concluded that the nature, extent, and quality of services provided to the fund under the Advisory Contracts should continue to benefit the shareholders of the fund.

Competitiveness of Management Fee and Total Expense Ratio. The Board considered the fund's management fee and total expense ratio compared to "mapped groups" of competitive funds and classes created for the purpose of facilitating the Trustees' competitive analysis of management fees and total expenses. Fidelity creates "mapped groups" by combining similar Lipper investment objective categories that have comparable investment mandates. Combining Lipper investment objective categories aids the Board's management fee and total expense ratio comparisons by broadening the competitive group used for comparison.

Management Fee. The Board considered two proprietary management fee comparisons for the 12-month (or shorter) periods shown in basis points (BP) in the chart below. The group of Lipper funds used by the Board for management fee comparisons is referred to below as the "Total Mapped Group" and is broader than the Lipper peer group used by the Board for performance comparisons. The Total Mapped Group comparison focuses on a fund's standing in terms of gross management fees before expense reimbursements or caps relative to the total universe of funds with comparable investment mandates, regardless of whether their management fee structures also are comparable. Funds with comparable investment mandates offer exposure to similar types of securities. Funds with comparable management fee structures have similar management fee contractual arrangements (e.g., flat rate charged for advisory services, all-inclusive fee rate, etc.). "TMG %" represents the percentage of funds in the Total Mapped Group that had management fees that were lower than the fund's. For example, a hypothetical TMG % of 20% would mean that 80% of the funds in the Total Mapped Group had higher, and 20% had lower, management fees than the fund. The fund's actual TMG %s and the number of funds in the Total Mapped Group are in the chart below. The "Asset-Sized Peer Group" (ASPG) comparison focuses on a fund's standing relative to a subset of non-Fidelity funds within the Total Mapped Group that are similar in size and management fee structure. For example, if a fund is in the first quartile of the ASPG, the fund's management fee ranks in the least expensive or lowest 25% of funds in the ASPG. The ASPG represents at least 15% of the funds in the Total Mapped Group with comparable asset size and management fee structures, subject to a minimum of 50 funds (or all funds in the Total Mapped Group if fewer than 50). Additional information, such as the ASPG quartile in which the fund's management fee rate ranked, is also included in the chart and was considered by the Board.

Fidelity SAI Long-Term Treasury Bond Index Fund

The Board noted that the fund's management fee rate ranked below the median of its Total Mapped Group and below the median of its ASPG for 2019.

The Board noted that it and the boards of other Fidelity funds formed an ad hoc Committee on Group Fee, which meets periodically, to conduct an in-depth review of the "group fee" component of the management fee of funds with such management fee structures. The Committee's focus included the mechanics of the group fee, the competitive landscape of group fee structures, Fidelity funds with no group fee component (such as the fund) and investment products not included in group fee assets. The Board also considered that, for funds subject to the group fee, FMR agreed to voluntarily waive fees over a specified period of time in amounts designed to account for assets converted from certain funds to certain collective investment trusts.

Based on its review, the Board concluded that the fund's management fee is fair and reasonable in light of the services that the fund receives and the other factors considered.

Total Expense Ratio. In its review of the fund's total expense ratio, the Board considered the fund's management fee rate as well as other fund expenses, such as custodial, legal, and audit fees. The Board also noted that Fidelity may agree to waive fees or reimburse expenses from time to time, and the extent to which, if any, it has done so for the fund. As part of its review, the Board also considered the current and historical total expense ratios of the fund compared to competitive fund median expenses. The fund is compared to those funds and classes in the Total Mapped Group (used by the Board for management fee comparisons) that have a similar sales load structure.

The Board noted that the fund's total expense ratio ranked below the competitive median for 2019.

The Board further considered that FMR has contractually agreed to reimburse the fund to the extent that total operating expenses, with certain exceptions, as a percentage of its average net assets, exceed 0.03% through June 30, 2021.

Fees Charged to Other Fidelity Clients. The Board also considered Fidelity fee structures and other information with respect to clients of Fidelity, such as other funds advised or subadvised by Fidelity, pension plan clients, and other institutional clients with similar mandates. The Board noted that a joint ad hoc committee created by it and the boards of other Fidelity funds periodically reviews and compares Fidelity's institutional investment advisory business with its business of providing services to the Fidelity funds and also noted the most recent findings of the committee. The Board noted that the committee's review included a consideration of the differences in services provided, fees charged, and costs incurred, as well as competition in the markets serving the different categories of clients.

Based on its review of total expense ratios and fees charged to other Fidelity clients, the Board concluded that the fund's total expense ratio was reasonable in light of the services that the fund and its shareholders receive and the other factors considered.

Costs of the Services and Profitability. The Board considered the revenues earned and the expenses incurred by Fidelity in conducting the business of developing, marketing, distributing, managing, administering and servicing the fund and servicing the fund's shareholders. The Board also considered the level of Fidelity's profits in respect of all the Fidelity funds.

On an annual basis, Fidelity presents to the Board information about the profitability of its relationships with the fund. Fidelity calculates profitability information for each fund, as well as aggregate profitability information for groups of Fidelity funds and all Fidelity funds, using a series of detailed revenue and cost allocation methodologies which originate with the books and records of Fidelity on which Fidelity's audited financial statements are based. The Audit Committee of the Board reviews any significant changes from the prior year's methodologies and the full Board approves such changes.

A public accounting firm has been engaged annually by the Board as part of the Board's assessment of Fidelity's profitability analysis. The engagement includes the review and assessment of the methodologies used by Fidelity in determining the revenues and expenses attributable to Fidelity's mutual fund business, and completion of agreed-upon procedures in respect of the mathematical accuracy of certain fund profitability information and its conformity to established allocation methodologies. After considering the reports issued under the engagement and information provided by Fidelity, the Board concluded that while other allocation methods may also be reasonable, Fidelity's profitability methodologies are reasonable in all material respects.

The Board also reviewed Fidelity's non-fund businesses and potential indirect benefits such businesses may have received as a result of their association with Fidelity's mutual fund business (i.e., fall-out benefits) as well as cases where Fidelity's affiliates may benefit from the funds' business. The Board considered areas where potential indirect benefits to the Fidelity funds from their relationships with Fidelity may exist. The Board also considered that in 2019 a joint ad hoc committee created by it and the boards of other Fidelity funds evaluated potential fall-out benefits (PFOB Committee). The Board noted that it considered the PFOB Committee's findings in connection with its consideration of the renewal of the Advisory Contracts.

The Board considered the costs of the services provided by and the profits realized by Fidelity in connection with the operation of the fund, including the conclusions of the PFOB Committee, and was satisfied that the profitability was not excessive.

Economies of Scale. The Board considered whether there have been economies of scale in respect of the management of the Fidelity funds, whether the Fidelity funds (including the fund) have appropriately benefited from any such economies of scale, and whether there is potential for realization of any further economies of scale. The Board considered the extent to which the fund will benefit from economies of scale as assets grow through increased services to the fund, through waivers or reimbursements, or through fee or expense ratio reductions. The Board also noted that a committee (the Economies of Scale Committee) created by it and the boards of other Fidelity funds periodically analyzes whether Fidelity attains economies of scale in respect of the management and servicing of the Fidelity funds, whether the Fidelity funds have appropriately benefited from such economies of scale, and whether there is potential for realization of any further economies of scale.

The Board concluded, taking into account the analysis of the Economies of Scale Committee, that economies of scale, if any, are being appropriately shared between fund shareholders and Fidelity.

Additional Information Requested by the Board. In order to develop fully the factual basis for consideration of the Fidelity funds' advisory contracts, the Board requested and received additional information on certain topics, including: (i) Fidelity's fund profitability methodology, profitability trends for certain funds, the allocation of various costs to different funds, and the impact of certain factors on fund profitability results; (ii) portfolio manager changes that have occurred during the past year and the amount of the investment that each portfolio manager has made in the Fidelity fund(s) that he or she manages; (iii) Fidelity's compensation structure for portfolio managers, research analysts, and other key personnel, including its effects on fund profitability, the rationale for the compensation structure, and the extent to which current market conditions have affected retention and recruitment; (iv) the arrangements with and compensation paid to certain fund sub-advisers on behalf of the Fidelity funds and the treatment of such compensation within Fidelity's fund profitability methodology; (v) the terms of the funds' various management fee structures, including the basic group fee and the terms of Fidelity's voluntary expense limitation agreements; (vi) Fidelity's transfer agent fee, expense, and service structures for different funds and classes relative to competitive trends; (vii) the impact on fund profitability of recent industry trends, such as the growth in passively managed funds and outflows from actively managed equity funds; and (viii) explanations regarding the relative total expense ratios of certain funds and classes, total expense competitive trends and methodologies for total expense competitive comparisons, and actions that might be taken by Fidelity to reduce total expense ratios for certain classes. In addition, the Board considered its discussions with Fidelity regarding Fidelity's efforts to maintain the continuous investment and shareholder services necessary for the funds during the current pandemic and economic circumstances.

Based on its evaluation of all of the conclusions noted above, and after considering all factors it believed relevant, the Board concluded that the advisory fee arrangements are fair and reasonable, and that the fund's Advisory Contracts should be renewed.

Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940 (the Liquidity Rule) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Fund has adopted and implemented a liquidity risk management program pursuant to the Liquidity Rule (the Program) effective December 1, 2018. The Program is reasonably designed to assess and manage the Fund’s liquidity risk and to comply with the requirements of the Liquidity Rule. The Fund’s Board of Trustees (the Board) has designated the Fund’s investment adviser as administrator of the Program. The Fidelity advisers have established a Liquidity Risk Management Committee (the LRM Committee) to manage the Program for each of the Fidelity Funds. The LRM Committee monitors the adequacy and effectiveness of implementation of the Program and on a periodic basis assesses each Fund’s liquidity risk based on a variety of factors including (1) the Fund’s investment strategy, (2) portfolio liquidity and cash flow projections during normal and reasonably foreseeable stressed conditions, (3) shareholder redemptions, (4) borrowings and other funding sources and (5) in the case of exchange-traded funds, certain additional factors including the effect of the Fund’s prices and spreads, market participants, and basket compositions on the overall liquidity of the Fund’s portfolio, as applicable.

In accordance with the Program, each of the Fund’s portfolio investments is classified into one of four liquidity categories described below based on a determination of a reasonable expectation for how long it would take to convert the investment to cash (or sell or dispose of the investment) without significantly changing its market value.

Highly liquid investments – cash or convertible to cash within three business days or less
Moderately liquid investments – convertible to cash in three to seven calendar days
Less liquid investments – can be sold or disposed of, but not settled, within seven calendar days
Illiquid investments – cannot be sold or disposed of within seven calendar days

Liquidity classification determinations take into account a variety of factors including various market, trading and investment-specific considerations, as well as market depth, and generally utilize analysis from a third-party liquidity metrics service.

The Liquidity Rule places a 15% limit on a fund’s illiquid investments and requires funds that do not primarily hold assets that are highly liquid investments to determine and maintain a minimum percentage of the fund’s net assets to be invested in highly liquid investments (highly liquid investment minimum or HLIM). The Program includes provisions reasonably designed to comply with the 15% limit on illiquid investments and for determining, periodically reviewing and complying with the HLIM requirement as applicable.

At a recent meeting of the Fund’s Board of Trustees, the LRM Committee provided a written report to the Board pertaining to the operation, adequacy, and effectiveness of implementation of the Program for the annual period from December 1, 2019 through November 30, 2020. The report concluded that the Program has been implemented and is operating effectively and is reasonably designed to assess and manage the Fund’s liquidity risk.

Fidelity Investments

SV5-ANN-0421
1.9869414.105

Fidelity® Series Long-Term Treasury Bond Index Fund

Annual Report

February 28, 2021

Contents

Note to Shareholders
Performance
Management's Discussion of Fund Performance
Investment Summary
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions
Board Approval of Investment Advisory Contracts and Management Fees
Liquidity Risk Management Program

You may also call 1-800-544-8544 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Performance: The Bottom Line

Average Annual Total Returns

For the periods ended February 28, 2021	Past 1 year	Life of fund^A
Fidelity® Series Long-Term Treasury Bond Index	(6.47)%	2.34%

^A From July 7, 2016

$10,000 Over Life of Fund

Let's say hypothetically that $10,000 was invested in Fidelity® Series Long-Term Treasury Bond Index Fund on July 7, 2016, when the fund started.

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. Long Treasury Bond Index performed over the same period.

	Period Ending Values
	$11,138	Fidelity® Series Long-Term Treasury Bond Index
	$11,199	Bloomberg Barclays U.S. Long Treasury Bond Index

Management's Discussion of Fund Performance

Comments from Co-Portfolio Managers Brandon Bettencourt and Richard Munclinger: For the fiscal year, the fund returned -6.47%, nearly in line, net of fees, with the -6.02% return of the benchmark, the Bloomberg Barclays Long-Term Treasury Bond Index. This result met our goal of producing monthly returns, before expenses, that closely match the benchmark’s return. We use a method known as stratified sampling, which matches the index’s risk factors, but does not always hold all bonds in the exact proportions of the index. Early in the period, Treasuries posted very strong gains as the U.S. Federal Reserve cut the federal funds rate and undertook massive quantitative easing to support the economy and the financial markets amid the onset of the COVID-19 pandemic. Longer-term Treasury yields declined through August, then began an uptrend that continued through period end. Treasuries came under significant pressure in early 2021 when investors gravitated toward riskier assets and away from U.S. government bonds, anticipating a rebounding economy and a potential return of inflation in light of accommodative monetary policy and expansive fiscal spending. For the year, long-maturity Treasuries, with their greater sensitivity to interest-rate movements, posted a loss as the yield curve steepened. Shorter-term Treasuries posted modest gains.

Note to shareholders: On October 1, 2020, Richard Munclinger will assume co-management responsibilities for the fund, succeeding Jay Small.

Investment Summary (Unaudited)

Coupon Distribution as of February 28, 2021

	% of fund's investments
1 - 1.99%	22.1
2 - 2.99%	29.9
3 - 3.99%	37.5
4 - 4.99%	8.0
5 - 5.99%	0.3

Coupon distribution shows the range of stated interest rates on the fund's investments, excluding short-term investments.

Asset Allocation (% of fund's net assets)

As of February 28, 2021
	U.S. Treasury Obligations	99.7%
	Short-Term Investments and Net Other Assets (Liabilities)	0.3%

Schedule of Investments February 28, 2021

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.7%
	Principal Amount	Value
U.S. Treasury Obligations - 99.7%
U.S. Treasury Bonds:
1.125% 5/15/40	$368,987,000	$316,982,895
1.125% 8/15/40	192,972,000	165,051,364
1.25% 5/15/50	273,466,000	220,845,158
1.375% 11/15/40	553,772,000	495,279,833
1.375% 8/15/50	137,060,000	114,423,684
1.625% 11/15/50	193,208,000	171,804,176
1.875% 2/15/41	359,735,000	352,034,423
1.875% 2/15/51	289,550,000	274,167,656
2% 2/15/50	373,609,000	363,933,110
2.25% 8/15/46	73,540,000	75,553,732
2.25% 8/15/49	182,587,000	187,836,376
2.375% 11/15/49	348,093,000	367,863,596
2.5% 2/15/45	126,949,000	136,574,313
2.5% 2/15/46	117,718,000	126,684,801
2.5% 5/15/46	137,416,000	147,813,452
2.75% 8/15/42	92,800,000	104,519,625
2.75% 11/15/42	103,434,000	116,371,330
2.75% 8/15/47	122,380,000	138,437,595
2.75% 11/15/47	221,377,000	250,458,674
2.875% 5/15/43	133,182,000	153,060,454
2.875% 8/15/45	36,332,000	41,787,477
2.875% 11/15/46	134,025,000	154,615,637
2.875% 5/15/49	419,448,000	489,216,254
3% 5/15/42	37,139,000	43,480,194
3% 11/15/44	109,417,000	128,248,692
3% 5/15/45	135,524,000	159,155,998
3% 11/15/45 (a)	65,242,000	76,697,578
3% 2/15/47	472,920,000	558,803,011
3% 5/15/47	214,228,000	253,332,978
3% 2/15/48	314,679,000	373,115,872
3% 8/15/48	19,266,000	22,885,148
3% 2/15/49	135,087,000	160,832,683
3.125% 11/15/41	59,163,000	70,644,320
3.125% 2/15/43	114,181,000	136,366,012
3.125% 8/15/44	75,106,000	89,807,413
3.125% 5/15/48	379,284,000	459,970,747
3.375% 5/15/44	133,850,000	166,313,853
3.375% 11/15/48	162,285,000	206,171,682
3.5% 2/15/39	15,614,000	19,563,854
3.625% 8/15/43	88,337,000	113,726,987
3.625% 2/15/44	160,111,000	206,418,103
3.75% 8/15/41	65,152,000	84,814,670
3.75% 11/15/43	138,249,000	181,300,603
3.875% 8/15/40	46,505,000	61,293,953
4.25% 5/15/39	47,740,000	65,461,610
4.25% 11/15/40	61,567,000	85,080,303
4.375% 2/15/38	7,669,000	10,581,722
4.375% 11/15/39	22,162,000	30,903,004
4.375% 5/15/40	74,926,000	104,858,352
4.375% 5/15/41	51,585,000	72,609,917
4.5% 2/15/36 (a)	139,287,000	191,465,217
4.5% 5/15/38	15,609,000	21,854,429
4.5% 8/15/39	51,449,000	72,687,790
4.625% 2/15/40	35,743,000	51,443,392
4.75% 2/15/37	20,223,000	28,756,158
4.75% 2/15/41	19,013,000	27,956,537
5% 5/15/37	22,627,000	33,053,981
		9,334,972,378
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $9,180,282,694)		9,334,972,378
	Shares	Value

Money Market Funds - 2.2%
Fidelity Cash Central Fund 0.07% (b)	66,118,724	$66,131,948
Fidelity Securities Lending Cash Central Fund 0.08% (b)(c)	137,558,939	137,572,695
TOTAL MONEY MARKET FUNDS
(Cost $203,704,643)		203,704,643
TOTAL INVESTMENT IN SECURITIES - 101.9%
(Cost $9,383,987,337)		9,538,677,021
NET OTHER ASSETS (LIABILITIES) - (1.9)%		(182,246,057)
NET ASSETS - 100%		$9,356,430,964

Legend

(a) Security or a portion of the security is on loan at period end.

(b) Affiliated fund that is generally available only to investment companies and other accounts managed by Fidelity Investments. The rate quoted is the annualized seven-day yield of the fund at period end. A complete unaudited listing of the fund's holdings as of its most recent quarter end is available upon request. In addition, each Fidelity Central Fund's financial statements, which are not covered by the Fund's Report of Independent Registered Public Accounting Firm, are available on the SEC's website or upon request.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$43,356
Fidelity Securities Lending Cash Central Fund	82,773
Total	$126,129

Investment Valuation

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$9,334,972,378	$--	$9,334,972,378	$--
Money Market Funds	203,704,643	203,704,643	--	--
Total Investments in Securities:	$9,538,677,021	$203,704,643	$9,334,972,378	$--

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

		February 28, 2021
Assets
Investment in securities, at value (including securities loaned of $135,655,910) — See accompanying schedule: Unaffiliated issuers (cost $9,180,282,694)	$9,334,972,378
Fidelity Central Funds (cost $203,704,643)	203,704,643
Total Investment in Securities (cost $9,383,987,337)		$9,538,677,021
Cash		35,514
Receivable for investments sold		54,583,599
Receivable for fund shares sold		962,821,931
Interest receivable		36,890,029
Distributions receivable from Fidelity Central Funds		12,980
Total assets		10,593,021,074
Liabilities
Payable for investments purchased	$1,095,810,787
Payable for fund shares redeemed	3,178,688
Other payables and accrued expenses	27,940
Collateral on securities loaned	137,572,695
Total liabilities		1,236,590,110
Net Assets		$9,356,430,964
Net Assets consist of:
Paid in capital		$9,193,335,911
Total accumulated earnings (loss)		163,095,053
Net Assets		$9,356,430,964
Net Asset Value, offering price and redemption price per share ($9,356,430,964 ÷ 1,122,963,666 shares)		$8.33

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended February 28, 2021
Investment Income
Interest (including $16,977 from security lending)		$142,750,594
Income from Fidelity Central Funds (including $82,773 from security lending)		126,129
Total income		142,876,723
Expenses
Custodian fees and expenses	$61,518
Independent trustees' fees and expenses	22,320
Miscellaneous	15,813
Total expenses before reductions	99,651
Expense reductions	(549)
Total expenses after reductions		99,102
Net investment income (loss)		142,777,621
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	624,890,012
Fidelity Central Funds	459
Total net realized gain (loss)		624,890,471
Change in net unrealized appreciation (depreciation) on investment securities		(1,358,596,563)
Net gain (loss)		(733,706,092)
Net increase (decrease) in net assets resulting from operations		$(590,928,471)

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended February 28, 2021	Year ended February 29, 2020
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$142,777,621	$237,951,830
Net realized gain (loss)	624,890,471	716,690,289
Change in net unrealized appreciation (depreciation)	(1,358,596,563)	1,673,690,379
Net increase (decrease) in net assets resulting from operations	(590,928,471)	2,628,332,498
Distributions to shareholders	(866,204,921)	(755,166,735)
Share transactions
Proceeds from sales of shares	5,263,477,577	2,648,476,554
Reinvestment of distributions	866,203,841	747,981,114
Cost of shares redeemed	(2,730,339,649)	(8,321,844,724)
Net increase (decrease) in net assets resulting from share transactions	3,399,341,769	(4,925,387,056)
Total increase (decrease) in net assets	1,942,208,377	(3,052,221,293)
Net Assets
Beginning of period	7,414,222,587	10,466,443,880
End of period	$9,356,430,964	$7,414,222,587
Other Information
Shares
Sold	556,676,054	281,785,944
Issued in reinvestment of distributions	93,021,977	82,120,391
Redeemed	(263,745,349)	(868,162,755)
Net increase (decrease)	385,952,682	(504,256,420)

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Series Long-Term Treasury Bond Index Fund


Years ended February 28,	2021	2020 ^A	2019	2018	2017 ^B
Selected Per–Share Data
Net asset value, beginning of period	$10.06	$8.43	$8.36	$8.59	$10.00
Income from Investment Operations
Net investment income (loss)^C	.201	.249	.248	.241	.119
Net realized and unrealized gain (loss)	(.752)	2.319	.069	(.244)	(1.410)
Total from investment operations	(.551)	2.568	.317	(.003)	(1.291)
Distributions from net investment income	(.199)	(.243)	(.247)	(.227)	(.119)
Distributions from net realized gain	(.980)	(.695)	–	–	–
Total distributions	(1.179)	(.938)	(.247)	(.227)	(.119)
Net asset value, end of period	$8.33	$10.06	$8.43	$8.36	$8.59
Total Return^D,^E	(6.47)%	31.91%	3.84%	(.12)%	(12.96)%
Ratios to Average Net Assets^F,^G
Expenses before reductions	- %^H	- %^H	- %^H	- %^H	.19%^I
Expenses net of fee waivers, if any	- %^H	- %^H	- %^H	- %^H	.19%^I
Expenses net of all reductions	- %^H	- %^H	- %^H	- %^H	.19%^I
Net investment income (loss)	2.03%	2.68%	2.98%	2.76%	2.02%^I
Supplemental Data
Net assets, end of period (000 omitted)	$9,356,431	$7,414,223	$10,466,444	$4,380,830	$10,734
Portfolio turnover rate^J	56%	33%^K	23%	15%	45%^I

^A For the year ended February 29.

^B For the period July 7, 2016 (commencement of operations) to February 28, 2017.

^C Calculated based on average shares outstanding during the period.

^D Total returns for periods of less than one year are not annualized.

^E Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^F Fees and expenses of any underlying mutual funds or exchange-traded funds (ETFs) are not included in the Fund's expense ratio. The Fund indirectly bears its proportionate share of these expenses. For additional expense information related to investments in Fidelity Central Funds, please refer to the "Investments in Fidelity Central Funds" note found in the Notes to Financial Statements section of the most recent Annual or Semi-Annual report.

^G Expense ratios reflect operating expenses of the class. Expenses before reductions do not reflect amounts reimbursed, waived, or reduced through arrangements with the investment advisor, brokerage services, or other offset arrangements, if applicable, and do not represent the amount paid by the class during periods when reimbursements, waivers or reductions occur.

^H Amount represents less than .005%.

^I Annualized

^J Amount does not include the portfolio activity of any underlying mutual funds or exchange-traded funds (ETFs).

^K Portfolio turnover rate excludes securities received or delivered in-kind.

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended February 28, 2021

1. Organization.

Fidelity Series Long-Term Treasury Bond Index Fund (the Fund) is a fund of Fidelity Salem Street Trust (the Trust) and is authorized to issue an unlimited number of shares. Shares are offered only to certain other Fidelity funds and Fidelity managed 529 plans. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Massachusetts business trust.

2. Investments in Fidelity Central Funds.

3. Significant Accounting Policies.

Investment Valuation. Investments are valued as of 4:00 p.m. Eastern time on the last calendar day of the period. The Board of Trustees (the Board) has delegated the day to day responsibility for the valuation of the Fund's investments to the Fair Value Committee (the Committee) established by the Fund's investment adviser. In accordance with valuation policies and procedures approved by the Board, the Fund attempts to obtain prices from one or more third party pricing vendors or brokers to value its investments. When current market prices, quotations or currency exchange rates are not readily available or reliable, investments will be fair valued in good faith by the Committee, in accordance with procedures adopted by the Board. Factors used in determining fair value vary by investment type and may include market or investment specific events, changes in interest rates and credit quality. The frequency with which these procedures are used cannot be predicted and they may be utilized to a significant extent. The Committee oversees the Fund's valuation policies and procedures and reports to the Board on the Committee's activities and fair value determinations. The Board monitors the appropriateness of the procedures used in valuing the Fund's investments and ratifies the fair value determinations of the Committee.

The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Valuation techniques used to value the Fund's investments by major category are as follows:

Debt securities, including restricted securities, are valued based on evaluated prices received from third party pricing vendors or from brokers who make markets in such securities. U.S. government and government agency obligations are valued by pricing vendors who utilize matrix pricing which considers yield or price of bonds of comparable quality, coupon, maturity and type or by broker-supplied prices. When independent prices are unavailable or unreliable, debt securities may be valued utilizing pricing methodologies which consider similar factors that would be used by third party pricing vendors. Debt securities are generally categorized as Level 2 in the hierarchy but may be Level 3 depending on the circumstances.

Investments in open-end mutual funds, including the Fidelity Central Funds, are valued at their closing net asset value (NAV) each business day and are categorized as Level 1 in the hierarchy.

Book-tax differences are primarily due to market discount and losses deferred due to wash sales.

As of period end, the cost and unrealized appreciation (depreciation) in securities, and derivatives if applicable, for federal income tax purposes were as follows:

Gross unrealized appreciation	$615,704,007
Gross unrealized depreciation	(457,486,183)
Net unrealized appreciation (depreciation)	$158,217,824
Tax Cost	$9,380,459,197

The tax-based components of distributable earnings as of period end were as follows:

Undistributed long-term capital gain	$5,639,760
Net unrealized appreciation (depreciation) on securities and other investments	$158,217,824

The tax character of distributions paid was as follows:

	February 28, 2021	February 29, 2020
Ordinary Income	$305,147,457	$ 301,445,649
Long-term Capital Gains	561,057,464	453,721,086
Total	$866,204,921	$ 755,166,735

4. Fees and Other Transactions with Affiliates.

Management Fee. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Fund with investment management related services for which the Fund does not pay a management fee. Under the management contract, the investment adviser or an affiliate pays all ordinary operating expenses of the Fund, except custody fees, fees and expenses of the independent Trustees, and certain miscellaneous expenses such as proxy and shareholder meeting expenses.

Prior Fiscal Year Affiliated Exchanges In-Kind. During the prior period, the Fund received investments, including accrued interest, valued at $65,239,961 in exchange for 6,383,558 shares of the Fund. The amount of in-kind exchanges is included in share transactions in the accompanying Statement of Changes in Net Assets.

5. Committed Line of Credit.

	Amount
Fidelity Series Long-Term Treasury Bond Index Fund	$15,813

During the period, there were no borrowings on this line of credit.

6. Security Lending.

Funds lend portfolio securities from time to time in order to earn additional income. Lending agents are used, including National Financial Services (NFS), an affiliate of the investment adviser. Pursuant to a securities lending agreement, NFS will receive a fee, which is capped at 9.9% of a fund's daily lending revenue, for its services as lending agent. A fund may lend securities to certain qualified borrowers, including NFS. On the settlement date of the loan, a fund receives collateral (in the form of U.S. Treasury obligations, letters of credit and/or cash) against the loaned securities and maintains collateral in an amount not less than 100% of the market value of the loaned securities during the period of the loan. The market value of the loaned securities is determined at the close of business of a fund and any additional required collateral is delivered to a fund on the next business day. A fund or borrower may terminate the loan at any time, and if the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund may apply collateral received from the borrower against the obligation. A fund may experience delays and costs in recovering the securities loaned. Any cash collateral received is invested in the Fidelity Securities Lending Cash Central Fund. Any loaned securities are identified as such in the Schedule of Investments, and the value of loaned securities and cash collateral at period end, as applicable, are presented in the Statement of Assets and Liabilities. Security lending income represents the income earned on investing cash collateral, less rebates paid to borrowers and any lending agent fees associated with the loan, plus any premium payments received for lending certain types of securities. Security lending income is presented in the Statement of Operations as a component of interest income and as a component of income from Fidelity Central Funds. Affiliated security lending activity, if any, was as follows:

	Total Security Lending Income Fees Paid to NFS	Security Lending Income From Securities Loaned to NFS	Value of Securities Loaned to NFS at Period End
Fidelity Series Long-Term Treasury Bond Index Fund	$8,856	$–	$–

7. Expense Reductions.

Through arrangements with the Fund's custodian, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses by $549.

8. Other.

At the end of the period, mutual funds managed by the investment adviser or its affiliates were the owners of record of all of the outstanding shares of the Fund.

9. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Salem Street Trust and Shareholders of Fidelity Series Long-Term Treasury Bond Index Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Fidelity Series Long-Term Treasury Bond Index Fund (one of the funds constituting Fidelity Salem Street Trust, referred to hereafter as the “Fund”) as of February 28, 2021, the related statement of operations for the year ended February 28, 2021, the statement of changes in net assets for each of the two years in the period ended February 28, 2021, including the related notes, and the financial highlights for each of the four years in the period ended February 28, 2021 and for the period July 7, 2016 (commencement of operations) to February 28, 2017 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of February 28, 2021, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended February 28, 2021 and the financial highlights for each of the four years in the period ended February 28, 2021 and for the period July 7, 2016 (commencement of operations) to February 28, 2017 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

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

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

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of February 28, 2021 by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

April 15, 2021

We have served as the auditor of one or more investment companies in the Fidelity group of funds since 1932.

Trustees and Officers

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-8544.

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Jonathan Chiel (1957)

Year of Election or Appointment: 2016

Trustee

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Jamie Pagliocco (1964)

Year of Election or Appointment: 2020

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Brett Segaloff (1972)

Year of Election or Appointment: 2021

Anti-Money Laundering (AML) Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (September 1, 2020 to February 28, 2021).

Actual Expenses

Hypothetical Example for Comparison Purposes

	Annualized Expense Ratio-^A	Beginning Account Value September 1, 2020	Ending Account Value February 28, 2021	Expenses Paid During Period-^B September 1, 2020 to February 28, 2021
Fidelity Series Long-Term Treasury Bond Index Fund	- %-^C
Actual		$1,000.00	$890.90	$--^D
Hypothetical-^E		$1,000.00	$1,024.79	$--^D

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^C Amount represents less than .005%.

^D Amount represents less than $.005.

^E 5% return per year before expenses

Distributions (Unaudited)

The Board of Trustees of Fidelity Series Long-Term Treasury Bond Index Fund voted to pay on April 12, 2021, to shareholders of record at the opening of business on April 9, 2021, a distribution of $0.006 per share derived from capital gains realized from sales of portfolio securities.

The fund hereby designates as a capital gain dividend with respect to the taxable year ended February 28, 2021, $542,332,291, or, if subsequently determined to be different, the net capital gain of such year.

A total of 99.91% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $144,247,405 of distributions paid in the calendar year 2020 as qualifying to be taxed as section 163(j) interest dividends.

The fund will notify shareholders in January 2022 of amounts for use in preparing 2021 income tax returns.

Board Approval of Investment Advisory Contracts and Management Fees

Fidelity Series Long-Term Treasury Bond Index Fund

At its September 2020 meeting, the Board unanimously determined to renew the fund's Advisory Contracts. In considering whether to renew the Advisory Contracts for the fund, the Board considered all factors it believed relevant and reached a determination, with the assistance of fund counsel and Independent Trustees' counsel and through the exercise of its business judgment, that the renewal of the Advisory Contracts was in the best interests of the fund and its shareholders and the fact that no fee is payable under the management contract was fair and reasonable.

Administrative Services. The Board considered (i) the nature, extent, quality, and cost of advisory and administrative services performed by the Investment Advisers and their affiliates under the Advisory Contracts and under separate agreements covering transfer agency, pricing and bookkeeping, and securities lending services for the fund; (ii) the nature and extent of the supervision of third party service providers, principally custodians, subcustodians, and pricing vendors; and (iii) the resources devoted to, and the record of compliance with, the fund's compliance policies and procedures.

Investment Performance. The Board considered whether the fund has operated in accordance with its investment objective, as well as its record of compliance with its investment restrictions. The Board reviewed the fund's absolute investment performance, as well as the fund's relative investment performance. In this regard, the Board noted that the fund is designed to offer an investment option for other investment companies and 529 plans managed by Fidelity and ultimately to enhance the performance of those investment companies and 529 plans.

Based on its review, the Board concluded that the nature, extent, and quality of services provided to the fund under the Advisory Contracts should continue to benefit the shareholders of the fund.

Competitiveness of Management Fee and Total Expense Ratio. The Board considered that the fund does not pay FMR a management fee for investment advisory services. The Board also noted that FMR or an affiliate undertakes to pay all operating expenses of the fund, except transfer agent fees, 12b-1 fees, Independent Trustee fees and expenses, custodian fees and expenses, proxy and shareholder meeting expenses, interest, taxes, and extraordinary expenses (such as litigation expenses). The Board further noted that the fund pays its non-operating expenses, including brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable.

Based on its review, the Board considered that the fund does not pay a management fee and concluded that the fund's total expense ratio was reasonable in light of the services that the fund and its shareholders receive and the other factors considered.

Costs of the Services and Profitability. The Board considered the level of Fidelity's profits in respect of all the Fidelity funds.

The Board concluded that the costs of the services provided by and the profits realized by Fidelity in connection with the operation of the fund were not relevant to the renewal of the Advisory Contracts because the fund pays no advisory fees and FMR or an affiliate bears all expenses of the fund, with limited exceptions.

Economies of Scale. The Board concluded that because the fund pays no advisory fees and FMR or an affiliate bears all expenses of the fund with certain limited exceptions, the realization of economies of scale was not a material factor in the Board's decision to renew the fund's Advisory Contracts.

Liquidity Risk Management Program

Highly liquid investments – cash or convertible to cash within three business days or less
Moderately liquid investments – convertible to cash in three to seven calendar days
Less liquid investments – can be sold or disposed of, but not settled, within seven calendar days
Illiquid investments – cannot be sold or disposed of within seven calendar days

Fidelity Investments

XS8-ANN-0421
1.9872674.104

Fidelity® SAI U.S. Treasury Bond Index Fund

Annual Report

February 28, 2021

Contents

Note to Shareholders
Performance
Management's Discussion of Fund Performance
Investment Summary
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions
Board Approval of Investment Advisory Contracts and Management Fees
Liquidity Risk Management Program

You may also call 1-800-544-3455 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Performance: The Bottom Line

Average Annual Total Returns

For the periods ended February 28, 2021	Past 1 year	Life of fund^A
Fidelity® SAI US. Treasury Bond Index Fund	(0.33)%	2.61%

^A From March 1, 2016

$10,000 Over Life of Fund

Let's say hypothetically that $10,000 was invested in Fidelity® SAI U.S. Treasury Bond Index Fund on March 1, 2016, when the fund started.

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. Treasury Index performed over the same period.

	Period Ending Values
	$11,374	Fidelity® SAI US. Treasury Bond Index Fund
	$11,418	Bloomberg Barclays U.S. Treasury Index

Management's Discussion of Fund Performance

Comments from Co-Portfolio Managers Brandon Bettencourt and Richard Munclinger: For the fiscal year, the fund returned -0.33%, nearly in line, net of fees, with the -0.13% return of the benchmark, the Bloomberg Barclays 1-30 Year Treasury Bond Index. This result met our goal of producing monthly returns, before expenses, that closely match the benchmark’s return. We use a method known as stratified sampling, which matches the index’s risk factors, but does not always hold all bonds in the exact proportions of the index. Early in the period, Treasuries posted very strong gains as the U.S. Federal Reserve cut the federal funds rate and undertook massive quantitative easing to support the economy and the financial markets amid the onset of the COVID-19 pandemic. Longer-term Treasury yields declined through August, then began an uptrend that continued through period end. Treasuries came under significant pressure in early 2021 when investors gravitated toward riskier assets and away from U.S. government bonds, anticipating a rebounding economy and a potential return of inflation in light of accommodative monetary policy and expansive fiscal spending. For the year, long-maturity Treasuries, with their greater sensitivity to interest-rate movements, posted a loss as the yield curve steepened. Shorter-term Treasuries posted modest gains.

Note to shareholders: On October 1, 2020, Richard Munclinger assumed co-management responsibilities for the fund, succeeding Jay Small.

Investment Summary (Unaudited)

Coupon Distribution as of February 28, 2021

	% of fund's investments
0.01 - 0.99%	38.5
1 - 1.99%	20.5
2 - 2.99%	27.6
3 - 3.99%	8.1
4 - 4.99%	0.8
5 - 5.99%	0.3
6 - 6.99%	0.6
7 - 7.99%	0.6

Coupon distribution shows the range of stated interest rates on the fund's investments, excluding short-term investments.

Asset Allocation (% of fund's net assets)

As of February 28, 2021
	U.S. Treasury Obligations	99.1%
	Short-Term Investments and Net Other Assets (Liabilities)	0.9%

Schedule of Investments February 28, 2021

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.1%
	Principal Amount	Value
U.S. Treasury Obligations - 99.1%
U.S. Treasury Bonds:
1.125% 5/15/40	$132,166,000	$113,538,854
1.125% 8/15/40	90,424,000	77,340,778
1.25% 5/15/50	32,705,000	26,411,842
1.375% 11/15/40	212,639,300	190,179,268
1.375% 8/15/50	50,820,000	42,426,759
1.625% 11/15/50	71,937,500	63,968,174
1.875% 2/15/51	31,551,000	29,874,853
2% 2/15/50	10,734,000	10,456,006
2.25% 8/15/46	28,177,000	28,948,565
2.25% 8/15/49	52,680,000	54,194,550
2.375% 11/15/49	29,883,000	31,580,261
2.5% 2/15/45	1,000	1,076
2.5% 2/15/46	26,923,000	28,973,776
2.5% 5/15/46	44,109,000	47,446,466
2.75% 8/15/42	21,638,000	24,370,643
2.75% 11/15/42	19,826,000	22,305,799
2.75% 8/15/47	56,931,000	64,400,970
2.75% 11/15/47	23,318,000	26,381,220
2.875% 5/15/43	21,584,000	24,805,581
2.875% 8/15/45	61,954,000	71,256,780
2.875% 11/15/46	19,408,000	22,389,706
2.875% 5/15/49	42,262,000	49,291,586
3% 5/15/42	8,638,000	10,112,871
3% 5/15/45	14,055,000	16,505,841
3% 11/15/45 (a)	11,404,000	13,406,382
3% 2/15/47	83,579,000	98,757,077
3% 5/15/47	17,092,000	20,211,958
3% 2/15/48	46,259,000	54,849,441
3% 2/15/49	82,597,000	98,338,827
3.125% 11/15/41	6,664,000	7,957,233
3.125% 2/15/43	1,000	1,194
3.125% 5/15/48	144,600,500	175,361,998
3.375% 11/15/48	129,468,300	164,480,372
3.5% 2/15/39	315,000	394,685
3.625% 8/15/43	1,000	1,287
3.625% 2/15/44	26,356,000	33,978,649
3.75% 8/15/41	12,045,000	15,680,143
3.75% 11/15/43	2,984,000	3,913,236
3.875% 8/15/40	10,674,000	14,068,415
4.25% 5/15/39	7,898,000	10,829,824
4.375% 2/15/38	17,484,000	24,124,505
4.375% 11/15/39	4,140,000	5,772,874
4.375% 5/15/41	817,000	1,149,991
4.5% 2/15/36 (a)	21,512,200	29,570,872
4.5% 8/15/39	3,831,000	5,412,485
4.625% 2/15/40	1,505,000	2,166,083
4.75% 2/15/37	13,000	18,485
5% 5/15/37	2,667,000	3,896,008
5.25% 11/15/28	1,000	1,303
5.25% 2/15/29	9,219,000	12,073,289
5.375% 2/15/31	7,762,000	10,697,916
5.5% 8/15/28	2,865,000	3,762,327
6% 2/15/26	3,771,000	4,746,304
6.125% 11/15/27	3,404,000	4,532,506
6.125% 8/15/29	244,000	340,704
6.25% 8/15/23	25,875,000	29,731,992
6.25% 5/15/30	5,578,000	7,998,983
6.5% 11/15/26	39,000	51,265
6.625% 2/15/27	50,000	66,705
6.75% 8/15/26	23,000	30,323
6.875% 8/15/25	11,691,000	14,924,292
7.125% 2/15/23	12,111,000	13,773,424
7.25% 8/15/22	38,000	41,974
7.5% 11/15/24	15,867,000	20,016,592
7.625% 11/15/22	50,000	56,420
7.625% 2/15/25	20,938,000	26,816,998
U.S. Treasury Notes:
0.125% 4/30/22	15,621,000	15,623,441
0.125% 5/31/22	43,758,000	43,764,837
0.125% 6/30/22	94,154,000	94,187,101
0.125% 7/31/22	125,348,000	125,362,690
0.125% 8/31/22	96,764,000	96,767,780
0.125% 9/30/22	131,290,000	131,300,256
0.125% 10/31/22	87,532,000	87,532,000
0.125% 11/30/22	105,495,300	105,495,300
0.125% 12/31/22	152,079,000	152,073,060
0.125% 1/31/23	185,186,000	185,164,298
0.125% 7/15/23	14,448,000	14,428,247
0.125% 8/15/23	92,745,000	92,589,217
0.125% 9/15/23	63,456,000	63,322,147
0.125% 10/15/23	69,957,000	69,782,108
0.125% 12/15/23	121,834,200	121,405,877
0.125% 1/15/24	127,763,000	127,243,963
0.25% 4/15/23	69,953,000	70,089,627
0.25% 6/15/23	141,205,000	141,442,181
0.25% 11/15/23	8,272,000	8,274,585
0.25% 5/31/25	17,544,000	17,307,567
0.25% 6/30/25	134,051,400	132,103,466
0.25% 7/31/25	72,929,000	71,803,728
0.25% 8/31/25	98,070,000	96,418,899
0.25% 9/30/25	132,518,000	130,157,523
0.25% 10/31/25	187,289,300	183,770,310
0.375% 3/31/22	18,347,000	18,397,168
0.375% 4/30/25	11,267,000	11,186,459
0.375% 11/30/25	63,502,000	62,601,561
0.375% 12/31/25	51,983,100	51,191,170
0.375% 1/31/26 (a)	133,405,000	131,237,169
0.375% 7/31/27	133,430,000	128,098,012
0.375% 9/30/27	79,026,000	75,608,743
0.5% 3/15/23	125,754,000	126,652,945
0.5% 3/31/25	66,275,000	66,205,100
0.5% 2/28/26	21,246,000	21,023,581
0.5% 4/30/27	3,544,000	3,443,633
0.5% 5/31/27	55,772,000	54,107,554
0.5% 6/30/27	23,781,000	23,046,204
0.5% 8/31/27	42,155,000	40,719,095
0.625% 3/31/27	27,705,000	27,166,051
0.625% 11/30/27	4,567,700	4,431,383
0.625% 12/31/27	95,418,900	92,466,878
0.625% 5/15/30	158,027,000	148,020,681
0.625% 8/15/30	91,228,900	85,170,731
0.75% 1/31/28	106,069,000	103,566,435
0.875% 11/15/30 (a)	121,018,900	115,383,957
1.125% 2/28/25	98,061,900	100,444,498
1.125% 2/28/27	3,938,000	3,981,533
1.125% 2/15/31	23,831,000	23,246,396
1.25% 7/31/23	5,561,000	5,703,066
1.25% 8/31/24	46,824,000	48,223,233
1.375% 10/15/22	45,043,000	45,949,139
1.375% 2/15/23	1,000	1,024
1.375% 6/30/23	2,164,000	2,223,679
1.375% 8/31/23	1,103,000	1,135,271
1.375% 9/30/23	6,179,000	6,364,611
1.5% 8/15/22	27,251,000	27,799,214
1.5% 9/15/22	28,784,000	29,393,411
1.5% 2/28/23	4,873,000	5,005,485
1.5% 3/31/23	29,712,000	30,544,168
1.5% 9/30/24	5,723,000	5,944,766
1.5% 10/31/24	2,615,000	2,716,433
1.5% 8/15/26	33,170,000	34,352,977
1.5% 2/15/30	25,293,000	25,676,347
1.625% 8/15/22	40,000	40,875
1.625% 8/31/22	15,416,000	15,762,258
1.625% 11/15/22	126,329,000	129,551,376
1.625% 4/30/23	2,979,000	3,072,908
1.625% 5/31/23	2,562,000	2,645,065
1.625% 10/31/23	5,035,000	5,222,239
1.625% 2/15/26	29,244,000	30,549,699
1.625% 5/15/26	25,238,000	26,342,163
1.625% 10/31/26	105,277,000	109,664,913
1.625% 8/15/29 (a)	101,646,000	104,596,117
1.75% 3/31/22	34,495,000	35,108,095
1.75% 4/30/22	2,435,000	2,481,607
1.75% 5/15/22	40,000	40,794
1.75% 5/31/22	18,289,000	18,665,496
1.75% 6/15/22	2,226,000	2,273,129
1.75% 6/30/22	26,870,000	27,458,831
1.75% 7/15/22	30,621,000	31,305,188
1.75% 9/30/22	9,000	9,231
1.75% 1/31/23	31,298,000	32,266,282
1.75% 5/15/23	2,767,000	2,862,872
1.75% 6/30/24	115,065,800	120,392,088
1.75% 7/31/24	84,636,000	88,603,313
1.75% 12/31/24	122,483,000	128,434,908
1.75% 11/15/29	4,107,000	4,264,863
1.875% 1/31/22	1,000	1,016
1.875% 3/31/22	22,568,000	22,996,439
1.875% 4/30/22	23,980,000	24,475,524
1.875% 5/31/22	6,821,000	6,972,075
1.875% 7/31/22	9,867,000	10,110,977
1.875% 8/31/22	6,473,000	6,642,158
1.875% 9/30/22	18,600,000	19,115,133
1.875% 10/31/22	17,759,000	18,273,040
1.875% 8/31/24	1,000	1,052
1.875% 6/30/26	17,105,000	18,069,829
1.875% 7/31/26	11,542,000	12,192,590
2% 7/31/22	6,247,000	6,412,692
2% 10/31/22	12,029,000	12,403,967
2% 2/15/23	49,134,000	50,915,108
2% 4/30/24	2,462,000	2,592,986
2% 5/31/24	119,408,000	125,840,173
2% 6/30/24	23,075,000	24,337,815
2% 2/15/25	6,597,000	6,985,089
2% 8/15/25	44,227,000	46,949,725
2% 11/15/26	124,450,000	132,194,095
2.125% 5/15/22	39,946,000	40,919,684
2.125% 6/30/22	8,062,000	8,277,092
2.125% 11/30/23	2,629,000	2,765,071
2.125% 2/29/24	3,213,000	3,389,213
2.125% 7/31/24	20,395,000	21,610,733
2.125% 9/30/24	17,004,000	18,045,495
2.125% 11/30/24	746,000	792,392
2.25% 12/31/23	35,029,000	36,999,381
2.25% 1/31/24	7,160,000	7,572,259
2.25% 4/30/24	1,000	1,061
2.25% 10/31/24	27,138,000	28,949,673
2.25% 11/15/24	49,622,000	52,934,656
2.25% 12/31/24	6,055,000	6,465,132
2.25% 11/15/25	26,723,000	28,688,602
2.25% 3/31/26	13,873,000	14,921,604
2.25% 2/15/27	44,880,000	48,338,916
2.25% 8/15/27	884,000	952,234
2.25% 11/15/27	43,442,000	46,778,210
2.375% 3/15/22	611,000	625,392
2.375% 1/31/23	12,947,000	13,502,811
2.375% 2/29/24	31,698,000	33,677,887
2.375% 8/15/24	35,598,000	38,045,363
2.375% 4/30/26	44,609,000	48,277,045
2.375% 5/15/27	90,912,000	98,660,828
2.375% 5/15/29	130,560,000	142,080,900
2.5% 3/31/23	10,634,000	11,154,900
2.5% 8/15/23	6,436,000	6,799,533
2.5% 1/31/24	109,906,000	117,024,130
2.5% 5/15/24	45,726,000	48,932,179
2.5% 1/31/25	5,697,000	6,143,636
2.5% 2/28/26	1,000	1,088
2.625% 2/28/23	4,000	4,198
2.625% 6/30/23	20,552,000	21,726,515
2.625% 12/31/23	9,868,000	10,527,923
2.625% 3/31/25	16,295,000	17,678,802
2.625% 1/31/26	1,204,000	1,316,311
2.625% 2/15/29	43,844,000	48,533,253
2.75% 4/30/23	25,222,000	26,630,885
2.75% 5/31/23	1,976,000	2,090,238
2.75% 7/31/23	18,682,000	19,834,300
2.75% 8/31/23	22,940,000	24,396,152
2.75% 11/15/23	22,659,000	24,197,334
2.75% 2/28/25	24,280,000	26,448,128
2.75% 6/30/25	9,260,000	10,120,529
2.75% 8/31/25	28,037,000	30,693,944
2.75% 2/15/28	90,801,200	100,853,176
2.875% 10/31/23	138,571,000	148,319,686
2.875% 11/30/23	29,487,000	31,614,441
2.875% 4/30/25	14,386,000	15,767,843
2.875% 5/31/25	5,889,000	6,462,717
2.875% 7/31/25	110,397,000	121,376,326
2.875% 5/15/28	127,285,000	142,683,501
2.875% 8/15/28	12,585,000	14,128,137
3% 9/30/25	7,460,000	8,257,870
3% 10/31/25	11,284,000	12,504,964
3.125% 11/15/28	40,703,000	46,493,638
		9,492,091,239
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $9,508,649,775)		9,492,091,239
	Shares	Value

Money Market Funds - 3.0%
Fidelity Cash Central Fund 0.07% (b)	72,844,536	$72,859,104
Fidelity Securities Lending Cash Central Fund 0.08% (b)(c)	208,188,314	208,209,133
TOTAL MONEY MARKET FUNDS
(Cost $281,068,237)		281,068,237
TOTAL INVESTMENT IN SECURITIES - 102.1%
(Cost $9,789,718,012)		9,773,159,476
NET OTHER ASSETS (LIABILITIES) - (2.1)%		(197,791,105)
NET ASSETS - 100%		$9,575,368,371

Legend

(a) Security or a portion of the security is on loan at period end.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$76,339
Fidelity Securities Lending Cash Central Fund	38,505
Total	$114,844

Investment Valuation

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$9,492,091,239	$--	$9,492,091,239	$--
Money Market Funds	281,068,237	281,068,237	--	--
Total Investments in Securities:	$9,773,159,476	$281,068,237	$9,492,091,239	$--

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

		February 28, 2021
Assets
Investment in securities, at value (including securities loaned of $204,444,877) — See accompanying schedule: Unaffiliated issuers (cost $9,508,649,775)	$9,492,091,239
Fidelity Central Funds (cost $281,068,237)	281,068,237
Total Investment in Securities (cost $9,789,718,012)		$9,773,159,476
Receivable for investments sold		90,968,576
Receivable for fund shares sold		11,299,635
Interest receivable		29,000,056
Distributions receivable from Fidelity Central Funds		18,793
Prepaid expenses		2,461
Receivable from investment adviser for expense reductions		250,117
Total assets		9,904,699,114
Liabilities
Payable for investments purchased	$118,090,457
Payable for fund shares redeemed	2,383,212
Distributions payable	37,367
Accrued management fee	268,647
Other payables and accrued expenses	341,927
Collateral on securities loaned	208,209,133
Total liabilities		329,330,743
Net Assets		$9,575,368,371
Net Assets consist of:
Paid in capital		$9,581,965,827
Total accumulated earnings (loss)		(6,597,456)
Net Assets		$9,575,368,371
Net Asset Value, offering price and redemption price per share ($9,575,368,371 ÷ 948,027,332 shares)		$10.10

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended February 28, 2021
Investment Income
Interest		$77,427,652
Income from Fidelity Central Funds (including $38,505 from security lending)		114,844
Total income		77,542,496
Expenses
Management fee	$1,944,051
Custodian fees and expenses	42,545
Independent trustees' fees and expenses	16,183
Registration fees	562,826
Audit	58,196
Legal	5,833
Miscellaneous	27,540
Total expenses before reductions	2,657,174
Expense reductions	(1,173,413)
Total expenses after reductions		1,483,761
Net investment income (loss)		76,058,735
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	521,029,675
Fidelity Central Funds	(1,125)
Total net realized gain (loss)		521,028,550
Change in net unrealized appreciation (depreciation) on investment securities		(637,667,798)
Net gain (loss)		(116,639,248)
Net increase (decrease) in net assets resulting from operations		$(40,580,513)

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended February 28, 2021	Year ended February 29, 2020
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$76,058,735	$152,827,404
Net realized gain (loss)	521,028,550	14,228,343
Change in net unrealized appreciation (depreciation)	(637,667,798)	627,860,895
Net increase (decrease) in net assets resulting from operations	(40,580,513)	794,916,642
Distributions to shareholders	(265,244,823)	(143,145,069)
Share transactions
Proceeds from sales of shares	9,928,949,717	6,461,593,978
Reinvestment of distributions	260,106,369	120,722,850
Cost of shares redeemed	(9,592,486,016)	(847,003,140)
Net increase (decrease) in net assets resulting from share transactions	596,570,070	5,735,313,688
Total increase (decrease) in net assets	290,744,734	6,387,085,261
Net Assets
Beginning of period	9,284,623,637	2,897,538,376
End of period	$9,575,368,371	$9,284,623,637
Other Information
Shares
Sold	937,458,981	648,927,757
Issued in reinvestment of distributions	24,913,150	11,869,544
Redeemed	(890,603,735)	(84,768,708)
Net increase (decrease)	71,768,396	576,028,593

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity SAI U.S. Treasury Bond Index Fund


Years ended February 28,	2021	2020 ^A	2019	2018	2017 ^B
Selected Per–Share Data
Net asset value, beginning of period	$10.60	$9.65	$9.55	$9.77	$10.00
Income from Investment Operations
Net investment income (loss)^C	.168	.229	.233	.192	.146
Net realized and unrealized gain (loss)	(.191)	.937	.072	(.247)	(.234)
Total from investment operations	(.023)	1.166	.305	(.055)	(.088)
Distributions from net investment income	(.175)	(.216)	(.205)	(.165)	(.133)
Distributions from net realized gain	(.302)	–	–	–	(.009)
Total distributions	(.477)	(.216)	(.205)	(.165)	(.142)
Net asset value, end of period	$10.10	$10.60	$9.65	$9.55	$9.77
Total Return^D	(.33)%	12.21%	3.23%	(.59)%	(.90)%
Ratios to Average Net Assets^E,^F
Expenses before reductions	.05%	.08%	.15%	.16%	.41%
Expenses net of fee waivers, if any	.03%	.03%	.03%	.04%	.10%
Expenses net of all reductions	.03%	.03%	.03%	.04%	.10%
Net investment income (loss)	1.56%	2.27%	2.45%	1.95%	1.46%
Supplemental Data
Net assets, end of period (000 omitted)	$9,575,368	$9,284,624	$2,897,538	$1,081,044	$30,735
Portfolio turnover rate^G	167%	23%	73%	144%	511%

^A For the year ended February 29.

^B For the period March 1, 2016 (commencement of operations) to February 28, 2017.

^C Calculated based on average shares outstanding during the period.

^D Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^G Amount does not include the portfolio activity of any underlying mutual funds or exchange-traded funds (ETFs).

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended February 28, 2021

1. Organization.

Fidelity SAI U.S. Treasury Bond Index Fund (the Fund) is a fund of Fidelity Salem Street Trust (the Trust) and is authorized to issue an unlimited number of shares. Shares are offered exclusively to certain clients of Fidelity Management & Research Company LLC (FMR) or its affiliates. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Massachusetts business trust.

2. Investments in Fidelity Central Funds.

3. Significant Accounting Policies.

Investment Valuation. Investments are valued as of 4:00 p.m. Eastern time on the last calendar day of the period. The Board of Trustees (the Board) has delegated the day to day responsibility for the valuation of the Fund's investments to the Fair Value Committee (the Committee) established by the Fund's investment adviser. In accordance with valuation policies and procedures approved by the Board, the Fund attempts to obtain prices from one or more third party pricing vendors or brokers to value its investments. When current market prices, quotations or currency exchange rates are not readily available or reliable, investments will be fair valued in good faith by the Committee, in accordance with procedures adopted by the Board. Factors used in determining fair value vary by investment type and may include market or investment specific events, changes in interest rates and credit quality. The frequency with which these procedures are used cannot be predicted and they may be utilized to a significant extent. The Committee oversees the Fund's valuation policies and procedures and reports to the Board on the Committee's activities and fair value determinations. The Board monitors the appropriateness of the procedures used in valuing the Fund's investments and ratifies the fair value determinations of the Committee.

The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Valuation techniques used to value the Fund's investments by major category are as follows:

Debt securities, including restricted securities, are valued based on evaluated prices received from third party pricing vendors or from brokers who make markets in such securities. U.S. government and government agency obligations are valued by pricing vendors who utilize matrix pricing which considers yield or price of bonds of comparable quality, coupon, maturity and type or by broker-supplied prices. When independent prices are unavailable or unreliable, debt securities may be valued utilizing pricing methodologies which consider similar factors that would be used by third party pricing vendors. Debt securities are generally categorized as Level 2 in the hierarchy but may be Level 3 depending on the circumstances.

Investments in open-end mutual funds, including the Fidelity Central Funds, are valued at their closing net asset value (NAV) each business day and are categorized as Level 1 in the hierarchy.

Book-tax differences are primarily due to market discount, capital loss carryforwards and losses deferred due to wash sales.

As of period end, the cost and unrealized appreciation (depreciation) in securities, and derivatives if applicable, for federal income tax purposes were as follows:

Gross unrealized appreciation	$181,217,832
Gross unrealized depreciation	(189,172,985)
Net unrealized appreciation (depreciation)	$(7,955,153)
Tax Cost	$9,781,114,629

The tax-based components of distributable earnings as of period end were as follows:

Undistributed ordinary income	$767,465
Undistributed long-term capital gain	$590,232
Net unrealized appreciation (depreciation) on securities and other investments	$(7,955,153)

The tax character of distributions paid was as follows:

	February 28, 2021	February 29, 2020
Ordinary Income	$77,034,667	$ 143,145,069
Long-term Capital Gains	188,210,156	–
Total	$265,244,823	$ 143,145,069

4. Fees and Other Transactions with Affiliates.

	Purchases ($)	Sales ($)
Fidelity SAI U.S. Treasury Bond Index Fund	–	433,073,882

5. Committed Line of Credit.

	Amount
Fidelity SAI U.S. Treasury Bond Index Fund	$11,771

During the period, there were no borrowings on this line of credit.

6. Security Lending.

	Total Security Lending Income Fees Paid to NFS	Security Lending Income From Securities Loaned to NFS	Value of Securities Loaned to NFS at Period End
Fidelity SAI U.S. Treasury Bond Index Fund	$4,519	$–	$–

7. Expense Reductions.

8. Other.

At the end of the period, Strategic Advisers Fidelity Core Income Fund were the owners of record of approximately 16% of the total outstanding shares of the Fund. Mutual funds managed by the investment adviser or its affiliates were the owners of record, in the aggregate, of approximately 20% of the total outstanding shares of the Fund.

9. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Salem Street Trust and Shareholders of Fidelity SAI U.S. Treasury Bond Index Fund

Opinion on the Financial Statements and Financial Highlights

We have audited the accompanying statement of assets and liabilities of Fidelity SAI U.S. Treasury Bond Index Fund (the "Fund"), a fund of Fidelity Salem Street Trust, including the schedule of investments, as of February 28, 2021, the related statement of operations for the year then ended, the statement of changes in net assets for each of the two years in the period then ended, the financial highlights for each of the four years in the period then ended and for the period from March 1, 2016 (commencement of operations) to February 28, 2017, 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 February 28, 2021, 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 four years in the period then ended and for the period from March 1, 2016 (commencement of operations) to February 28, 2017, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

/s/ Deloitte & Touche LLP

Boston, Massachusetts

April 13, 2021

We have served as the auditor of one or more of the Fidelity investment companies since 1999.

Trustees and Officers

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-3455.

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Jonathan Chiel (1957)

Year of Election or Appointment: 2016

Trustee

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Jamie Pagliocco (1964)

Year of Election or Appointment: 2020

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Brett Segaloff (1972)

Year of Election or Appointment: 2021

Anti-Money Laundering (AML) Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (September 1, 2020 to February 28, 2021).

Actual Expenses

Hypothetical Example for Comparison Purposes

	Annualized Expense Ratio-^A	Beginning Account Value September 1, 2020	Ending Account Value February 28, 2021	Expenses Paid During Period-^B September 1, 2020 to February 28, 2021
Fidelity SAI U.S. Treasury Bond Index Fund	.03%
Actual		$1,000.00	$966.00	$.15
Hypothetical-^C		$1,000.00	$1,024.65	$.15

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^C 5% return per year before expenses

Distributions (Unaudited)

The Board of Trustees of Fidelity SAI U.S. Treasury Bond Index Fund voted to pay on April 12th, 2021, to shareholders of record at the opening of business on April 9th, 2021, a distribution of $0.002 per share derived from capital gains realized from sales of portfolio securities.

The fund hereby designates as a capital gain dividend with respect to the taxable year ended February 28th, 2021, $262,965,251, or, if subsequently determined to be different, the net capital gain of such year.

A total of 99.90% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $92,041,612 of distributions paid in the calendar year 2020 as qualifying to be taxed as section 163(j) interest dividends.

The fund will notify shareholders in January 2022 of amounts for use in preparing 2021 income tax returns.

Board Approval of Investment Advisory Contracts and Management Fees

Fidelity SAI U.S. Treasury Bond Index Fund

Based on its review, the Board concluded that the nature, extent, and quality of services provided to the fund under the Advisory Contracts should continue to benefit the shareholders of the fund.

Fidelity SAI U.S. Treasury Bond Index Fund

The Board noted that the fund's management fee rate ranked below the median of its Total Mapped Group and below the median of its ASPG for 2019.

Based on its review, the Board concluded that the fund's management fee is fair and reasonable in light of the services that the fund receives and the other factors considered.

The Board noted that the fund's total expense ratio ranked below the competitive median for 2019.

The Board concluded, taking into account the analysis of the Economies of Scale Committee, that economies of scale, if any, are being appropriately shared between fund shareholders and Fidelity.

Liquidity Risk Management Program

Highly liquid investments – cash or convertible to cash within three business days or less
Moderately liquid investments – convertible to cash in three to seven calendar days
Less liquid investments – can be sold or disposed of, but not settled, within seven calendar days
Illiquid investments – cannot be sold or disposed of within seven calendar days

Fidelity Investments

UYB-ANN-0421
1.9872606.104

Fidelity® Short-Term Treasury Bond Index Fund

Fidelity® Intermediate Treasury Bond Index Fund

Fidelity® Long-Term Treasury Bond Index Fund

Annual Report

February 28, 2021

Contents

Note to Shareholders
Performance
Management's Discussion of Fund Performance
Fidelity® Short-Term Treasury Bond Index Fund
Investment Summary
Schedule of Investments
Financial Statements
Fidelity® Intermediate Treasury Bond Index Fund
Investment Summary
Schedule of Investments
Financial Statements
Fidelity® Long-Term Treasury Bond Index Fund
Investment Summary
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions
Board Approval of Investment Advisory Contracts and Management Fees
Liquidity Risk Management Program

You may also call 1-800-544-8544 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

This report and the financial statements contained herein are submitted for the general information of the shareholders of the Funds. This report is not authorized for distribution to prospective investors in the Funds unless preceded or accompanied by an effective prospectus.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Funds nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Fidelity® Short-Term Treasury Bond Index Fund

Performance: The Bottom Line

Average Annual Total Returns

For the periods ended February 28, 2021	Past 1 year	Past 5 years	Past 10 years
Fidelity® Short-Term Treasury Bond Index Fund	1.82%	1.96%	1.67%

The initial offering of Fidelity Short-Term Treasury Bond Index Fund (formerly named Institutional Premium Class) took place on October 4, 2017. Returns prior to October 4, 2017 are those of the former Premium Class and have not been restated to reflect current expenses.

$10,000 Over 10 Years

Let's say hypothetically that $10,000 was invested in Fidelity® Short-Term Treasury Bond Index Fund on February 28, 2011.

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. 1-5 Year Treasury Bond Index performed over the same period.

	Period Ending Values
	$11,801	Fidelity® Short-Term Treasury Bond Index Fund
	$11,893	Bloomberg Barclays U.S. 1-5 Year Treasury Bond Index

Fidelity® Intermediate Treasury Bond Index Fund

Performance: The Bottom Line

Average Annual Total Returns

For the periods ended February 28, 2021	Past 1 year	Past 5 years	Past 10 years
Fidelity® Intermediate Treasury Bond Index Fund	0.63%	2.74%	3.69%

The initial offering of Fidelity Intermediate Treasury Bond Index Fund (formerly named Institutional Premium Class) took place on October 4, 2017. Returns prior to October 4, 2017 are those of the former Premium Class and have not been restated to reflect current expenses.

$10,000 Over 10 Years

Let's say hypothetically that $10,000 was invested in Fidelity® Intermediate Treasury Bond Index Fund on February 28, 2011.

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. 5-10 Year Treasury Bond Index performed over the same period.

	Period Ending Values
	$14,362	Fidelity® Intermediate Treasury Bond Index Fund
	$14,473	Bloomberg Barclays U.S. 5-10 Year Treasury Bond Index

Fidelity® Long-Term Treasury Bond Index Fund

Performance: The Bottom Line

Average Annual Total Returns

For the periods ended February 28, 2021	Past 1 year	Past 5 years	Past 10 years
Fidelity® Long-Term Treasury Bond Index Fund	(6.32)%	4.11%	6.80%

The initial offering of Fidelity Long-Term Treasury Bond Index Fund (formerly named Institutional Premium Class) took place on October 4, 2017. Returns prior to October 4, 2017 are those of the former Premium Class and have not been restated to reflect current expenses.

$10,000 Over 10 Years

Let's say hypothetically that $10,000 was invested in Fidelity® Long-Term Treasury Bond Index Fund on February 28, 2011.

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. Long Treasury Bond Index performed over the same period.

	Period Ending Values
	$19,303	Fidelity® Long-Term Treasury Bond Index Fund
	$19,481	Bloomberg Barclays U.S. Long Treasury Bond Index

Management's Discussion of Fund Performance

Comments from Co-Portfolio Managers Brandon Bettencourt and Richard Munclinger: For the fiscal year, the Fidelity Treasury Bond Index Short-Term and Intermediate Funds posted a positive result, while the Long-Term Fund suffered a notable loss. The funds’ returns were nearly in line, net of fees, with the returns of their respective Bloomberg Barclays benchmarks, (For specific portfolio results, please refer to the Performance sections of this report.) These results met our goal of producing monthly returns, before expenses, that closely match the benchmarks’ returns. We use a method known as stratified sampling, which matches the indexes’ risk factors, but does not always hold all bonds in the exact proportions of the indexes. Early in the period, Treasuries posted very strong gains as the U.S. Federal Reserve cut the federal funds rate and undertook massive quantitative easing to support the economy and the financial markets. Longer-term Treasury yields declined through August, then began an uptrend that continued through period end. Treasuries came under significant pressure in early 2021 when investors gravitated toward riskier assets and away from U.S. government bonds, anticipating a rebounding economy and a potential return of inflation in light of accommodative monetary policy and expansive fiscal spending.

Note to shareholders: On October 1, 2020, Richard Munclinger will assume co-management responsibilities for the fund, succeeding Jay Small.

Fidelity® Short-Term Treasury Bond Index Fund

Investment Summary (Unaudited)

Coupon Distribution as of February 28, 2021

	% of fund's investments
0.01 - 0.99%	39.9
1 - 1.99%	24.5
2 - 2.99%	34.1
7 - 7.99%	0.2

Coupon distribution shows the range of stated interest rates on the fund's investments, excluding short-term investments.

Asset Allocation (% of fund's net assets)

As of February 28, 2021
	U.S. Treasury Obligations	99.8%
	Short-Term Investments and Net Other Assets (Liabilities)	0.2%

Fidelity® Short-Term Treasury Bond Index Fund

Schedule of Investments February 28, 2021

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.8%
	Principal Amount	Value
U.S. Treasury Obligations - 99.8%
U.S. Treasury Bonds:
7.125% 2/15/23	$4,361,000	$4,959,615
7.25% 8/15/22	1,725,000	1,905,384
U.S. Treasury Notes:
0.125% 4/30/22	60,483,000	60,492,450
0.125% 5/31/22	65,226,000	65,236,192
0.125% 6/30/22	30,506,000	30,516,725
0.125% 7/31/22	52,310,000	52,316,130
0.125% 8/31/22	72,045,000	72,047,814
0.125% 9/30/22	46,980,000	46,983,670
0.125% 10/31/22	29,260,000	29,260,000
0.125% 11/30/22	32,797,000	32,797,000
0.125% 12/31/22	13,941,000	13,940,455
0.125% 1/31/23	28,969,000	28,965,605
0.125% 2/28/23	20,044,000	20,044,000
0.125% 5/15/23	30,939,000	30,911,203
0.125% 7/15/23	10,174,000	10,160,090
0.125% 8/15/23	4,563,000	4,555,336
0.125% 9/15/23	40,711,000	40,625,125
0.125% 10/15/23	33,784,000	33,699,540
0.125% 12/15/23	26,501,000	26,407,833
0.125% 1/15/24	31,035,000	30,908,920
0.125% 2/15/24	29,370,000	29,241,506
0.25% 4/15/23	32,039,000	32,101,576
0.25% 6/15/23	23,274,000	23,313,093
0.25% 11/15/23	26,249,000	26,257,203
0.25% 5/31/25	61,252,000	60,426,534
0.25% 6/30/25	48,047,000	47,348,817
0.25% 7/31/25	48,040,000	47,298,758
0.25% 8/31/25	74,500,000	73,245,722
0.25% 9/30/25	64,535,000	63,385,470
0.25% 10/31/25	67,308,000	66,043,346
0.375% 3/31/22	17,450,000	17,497,715
0.375% 4/30/25	46,534,000	46,201,354
0.375% 11/30/25	74,783,000	73,722,600
0.375% 12/31/25	72,006,000	70,909,033
0.375% 1/31/26 (a)	60,890,000	59,900,538
0.5% 3/15/23	44,528,000	44,846,306
0.5% 3/31/25	68,271,000	68,198,995
0.5% 2/28/26	84,441,000	83,557,009
1.125% 2/28/25	58,919,000	60,350,548
1.25% 7/31/23	5,315,000	5,450,782
1.25% 8/31/24	39,218,000	40,389,944
1.375% 10/15/22	25,352,000	25,862,011
1.375% 2/15/23	43,014,000	44,055,745
1.375% 6/30/23	819,000	841,586
1.375% 8/31/23	9,952,000	10,243,174
1.375% 9/30/23	46,701,000	48,103,854
1.375% 1/31/25	30,507,000	31,549,720
1.5% 8/15/22	19,605,000	19,999,398
1.5% 9/15/22	22,987,000	23,473,678
1.5% 1/15/23	41,446,000	42,504,816
1.5% 2/28/23	36,757,000	37,756,331
1.5% 3/31/23	9,950,000	10,228,678
1.5% 9/30/24	32,261,000	33,511,114
1.5% 10/31/24	26,648,000	27,681,651
1.5% 11/30/24	57,512,000	59,747,330
1.625% 8/15/22	8,171,000	8,349,741
1.625% 8/31/22	20,192,000	20,645,531
1.625% 11/15/22	34,456,000	35,334,897
1.625% 12/15/22	20,655,000	21,208,490
1.625% 4/30/23	8,893,000	9,173,338
1.625% 5/31/23	11,556,000	11,930,667
1.625% 10/31/23	6,153,000	6,381,815
1.625% 2/15/26	13,915,000	14,536,283
1.75% 3/31/22	13,431,000	13,669,715
1.75% 4/30/22	10,280,000	10,476,766
1.75% 5/15/22	9,373,000	9,558,995
1.75% 5/31/22	20,104,000	20,517,860
1.75% 6/15/22	22,372,000	22,845,657
1.75% 6/30/22	25,239,000	25,792,089
1.75% 7/15/22	445,000	454,943
1.75% 9/30/22	1,463,000	1,500,489
1.75% 1/31/23	19,447,000	20,048,642
1.75% 5/15/23	3,063,000	3,169,128
1.75% 6/30/24	17,723,000	18,543,381
1.75% 7/31/24	5,038,000	5,274,156
1.75% 12/31/24	36,856,000	38,646,971
1.875% 3/31/22	24,447,000	24,911,111
1.875% 4/30/22	18,212,000	18,588,334
1.875% 5/31/22	9,884,000	10,102,915
1.875% 7/31/22	20,177,000	20,675,908
1.875% 8/31/22	10,725,000	11,005,274
1.875% 9/30/22	26,046,000	26,767,352
1.875% 10/31/22	89,000	91,576
1.875% 8/31/24	6,089,000	6,404,391
2% 7/31/22	10,059,000	10,325,799
2% 10/31/22	15,716,000	16,205,897
2% 11/30/22	31,713,000	32,746,150
2% 2/15/23	71,345,000	73,931,256
2% 4/30/24	1,027,000	1,081,640
2% 5/31/24	45,928,000	48,402,012
2% 6/30/24	5,177,000	5,460,319
2% 2/15/25	26,763,000	28,337,417
2% 8/15/25	22,660,000	24,055,006
2.125% 5/15/22	19,376,000	19,848,290
2.125% 6/30/22	11,177,000	11,475,199
2.125% 12/31/22	36,327,000	37,648,111
2.125% 11/30/23	33,695,000	35,438,979
2.125% 2/29/24	20,624,000	21,755,098
2.125% 3/31/24	36,376,000	38,412,203
2.125% 7/31/24	11,597,000	12,288,290
2.125% 9/30/24	3,566,000	3,784,418
2.125% 11/30/24	11,860,000	12,597,544
2.125% 5/15/25	18,150,000	19,346,057
2.25% 4/15/22	21,217,000	21,727,534
2.25% 12/31/23	46,911,000	49,549,744
2.25% 1/31/24	32,721,000	34,605,014
2.25% 4/30/24	19,488,000	20,674,028
2.25% 10/31/24	8,590,000	9,163,450
2.25% 11/15/24	31,103,000	33,179,368
2.25% 12/31/24	9,439,000	10,078,345
2.25% 11/15/25	17,188,000	18,452,258
2.375% 3/15/22	13,127,000	13,436,202
2.375% 1/31/23	43,821,000	45,702,222
2.375% 2/29/24	39,518,000	41,986,331
2.375% 8/15/24	24,724,000	26,423,775
2.5% 3/31/23	21,108,000	22,141,962
2.5% 8/15/23	17,029,000	17,990,873
2.5% 1/31/24	45,171,000	48,096,528
2.5% 5/15/24	35,174,000	37,640,302
2.5% 1/31/25	7,435,000	8,017,892
2.625% 12/15/21	1,000	1,020
2.625% 2/28/23	34,132,000	35,817,268
2.625% 6/30/23	19,528,000	20,643,995
2.625% 12/31/23	44,614,000	47,597,561
2.75% 4/30/23	32,250,000	34,051,465
2.75% 5/31/23	26,929,000	28,485,833
2.75% 7/31/23	4,030,000	4,278,569
2.75% 8/31/23	41,757,000	44,407,591
2.75% 11/15/23	17,933,000	19,150,482
2.75% 2/15/24	65,064,000	69,809,097
2.75% 2/28/25	39,898,000	43,460,767
2.875% 9/30/23	16,301,000	17,417,873
2.875% 10/31/23	34,530,000	36,959,239
2.875% 11/30/23	19,535,000	20,944,420
		3,863,616,130
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $3,815,224,341)		3,863,616,130
	Shares	Value

Money Market Funds - 1.3%
Fidelity Cash Central Fund 0.07% (b)	1,557,559	$1,557,871
Fidelity Securities Lending Cash Central Fund 0.08% (b)(c)	48,706,129	48,711,000
TOTAL MONEY MARKET FUNDS
(Cost $50,268,871)		50,268,871
TOTAL INVESTMENT IN SECURITIES - 101.1%
(Cost $3,865,493,212)		3,913,885,001
NET OTHER ASSETS (LIABILITIES) - (1.1)%		(42,928,052)
NET ASSETS - 100%		$3,870,956,949

Legend

(a) Security or a portion of the security is on loan at period end.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$12,262
Fidelity Securities Lending Cash Central Fund	16,139
Total	$28,401

Investment Valuation

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$3,863,616,130	$--	$3,863,616,130	$--
Money Market Funds	50,268,871	50,268,871	--	--
Total Investments in Securities:	$3,913,885,001	$50,268,871	$3,863,616,130	$--

See accompanying notes which are an integral part of the financial statements.

Fidelity® Short-Term Treasury Bond Index Fund

Financial Statements

Statement of Assets and Liabilities

		February 28, 2021
Assets
Investment in securities, at value (including securities loaned of $47,782,568) — See accompanying schedule: Unaffiliated issuers (cost $3,815,224,341)	$3,863,616,130
Fidelity Central Funds (cost $50,268,871)	50,268,871
Total Investment in Securities (cost $3,865,493,212)		$3,913,885,001
Receivable for investments sold		149,132,623
Receivable for fund shares sold		5,659,257
Interest receivable		13,465,822
Distributions receivable from Fidelity Central Funds		1,644
Other receivables		19
Total assets		4,082,144,366
Liabilities
Payable for investments purchased	$147,298,774
Payable for fund shares redeemed	14,617,566
Distributions payable	462,534
Accrued management fee	97,543
Collateral on securities loaned	48,711,000
Total liabilities		211,187,417
Net Assets		$3,870,956,949
Net Assets consist of:
Paid in capital		$3,808,762,979
Total accumulated earnings (loss)		62,193,970
Net Assets		$3,870,956,949
Net Asset Value, offering price and redemption price per share ($3,870,956,949 ÷ 359,748,460 shares)		$10.76

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended February 28, 2021
Investment Income
Interest (including $16,850 from security lending)		$43,925,358
Income from Fidelity Central Funds (including $16,139 from security lending)		28,401
Total income		43,953,759
Expenses
Management fee	$1,098,019
Independent trustees' fees and expenses	10,957
Miscellaneous	7,573
Total expenses before reductions	1,116,549
Expense reductions	(329)
Total expenses after reductions		1,116,220
Net investment income (loss)		42,837,539
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	27,343,238
Fidelity Central Funds	(1,894)
Total net realized gain (loss)		27,341,344
Change in net unrealized appreciation (depreciation) on investment securities		(21,899,618)
Net gain (loss)		5,441,726
Net increase (decrease) in net assets resulting from operations		$48,279,265

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended February 28, 2021	Year ended February 29, 2020
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$42,837,539	$45,687,301
Net realized gain (loss)	27,341,344	3,050,522
Change in net unrealized appreciation (depreciation)	(21,899,618)	83,430,408
Net increase (decrease) in net assets resulting from operations	48,279,265	132,168,231
Distributions to shareholders	(52,460,961)	(41,722,112)
Share transactions
Proceeds from sales of shares	3,914,439,434	1,457,023,913
Reinvestment of distributions	42,504,298	33,319,103
Cost of shares redeemed	(2,652,339,892)	(897,135,777)
Net increase (decrease) in net assets resulting from share transactions	1,304,603,840	593,207,239
Total increase (decrease) in net assets	1,300,422,144	683,653,358
Net Assets
Beginning of period	2,570,534,805	1,886,881,447
End of period	$3,870,956,949	$2,570,534,805
Other Information
Shares
Sold	360,498,942	138,870,001
Issued in reinvestment of distributions	3,917,521	3,164,786
Redeemed	(244,369,815)	(85,473,067)
Net increase (decrease)	120,046,648	56,561,720

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Short-Term Treasury Bond Index Fund


Years ended February 28,	2021	2020 ^A	2019	2018 ^B
Selected Per–Share Data
Net asset value, beginning of period	$10.72	$10.30	$10.22	$10.40
Income from Investment Operations
Net investment income (loss)^C	.127	.217	.191	.061
Net realized and unrealized gain (loss)	.068	.402	.065	(.182)
Total from investment operations	.195	.619	.256	(.121)
Distributions from net investment income	(.125)	(.199)	(.176)	(.059)
Distributions from net realized gain	(.030)	–	–	–
Total distributions	(.155)	(.199)	(.176)	(.059)
Net asset value, end of period	$10.76	$10.72	$10.30	$10.22
Total Return^D,^E	1.82%	6.06%	2.53%	(1.17)%
Ratios to Average Net Assets^F,^G
Expenses before reductions	.03%	.03%	.03%	.03%^H
Expenses net of fee waivers, if any	.03%	.03%	.03%	.03%^H
Expenses net of all reductions	.03%	.03%	.03%	.03%^H
Net investment income (loss)	1.17%	2.07%	1.85%	1.49%^H
Supplemental Data
Net assets, end of period (000 omitted)	$3,870,957	$2,570,535	$1,886,881	$483
Portfolio turnover rate^I	54%	46%	46%	41%

^A For the year ended February 29.

^B For the period October 4, 2017 (commencement of sale of shares) to February 28, 2018.

^C Calculated based on average shares outstanding during the period.

^D Total returns for periods of less than one year are not annualized.

^E Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^H Annualized

^I Amount does not include the portfolio activity of any underlying mutual funds or exchange-traded funds (ETFs).

See accompanying notes which are an integral part of the financial statements.

Fidelity® Intermediate Treasury Bond Index Fund

Investment Summary (Unaudited)

Coupon Distribution as of February 28, 2021

	% of fund's investments
0.01 - 0.99%	31.7
1 - 1.99%	27.0
2 - 2.99%	28.4
3 - 3.99%	3.8
5 - 5.99%	0.6
6 - 6.99%	1.1

Coupon distribution shows the range of stated interest rates on the fund's investments, excluding short-term investments.

Asset Allocation (% of fund's net assets)

As of February 28, 2021
	U.S. Treasury Obligations	99.6%
	Short-Term Investments and Net Other Assets (Liabilities)	0.4%

Fidelity® Intermediate Treasury Bond Index Fund

Schedule of Investments February 28, 2021

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.6%
	Principal Amount	Value
U.S. Treasury Obligations - 99.6%
U.S. Treasury Bonds:
5.25% 11/15/28	$8,521,000	$11,100,932
5.25% 2/15/29	794,000	1,039,830
5.5% 8/15/28	14,741,000	19,357,927
6.125% 11/15/27	15,013,000	19,990,161
6.25% 5/15/30	11,604,000	16,640,408
6.375% 8/15/27	2,958,000	3,961,294
6.5% 11/15/26	3,128,000	4,111,732
6.625% 2/15/27	4,115,000	5,489,828
6.75% 8/15/26	3,119,000	4,112,085
U.S. Treasury Notes:
0.375% 7/31/27	56,455,000	54,199,005
0.375% 9/30/27	109,883,000	105,131,418
0.5% 4/30/27	58,572,000	56,913,223
0.5% 5/31/27	58,246,000	56,507,721
0.5% 6/30/27	86,718,000	84,038,549
0.5% 8/31/27	149,495,000	144,402,827
0.5% 10/31/27	72,243,000	69,598,794
0.625% 3/31/27	24,376,000	23,901,811
0.625% 11/30/27	132,915,000	128,948,318
0.625% 12/31/27	163,643,000	158,580,295
0.625% 5/15/30	134,298,000	125,794,209
0.625% 8/15/30	215,282,000	200,985,930
0.75% 1/31/28	113,880,000	111,193,144
0.875% 11/15/30 (a)	247,876,000	236,334,269
1.125% 2/28/27	64,015,000	64,722,666
1.125% 2/29/28	82,731,000	82,808,560
1.125% 2/15/31	116,638,000	113,776,724
1.375% 8/31/26	73,195,000	75,322,230
1.5% 8/15/26	104,890,000	108,630,803
1.5% 1/31/27	23,879,300	24,682,428
1.5% 2/15/30	149,425,000	151,689,723
1.625% 5/15/26	92,793,000	96,852,694
1.625% 9/30/26	83,761,000	87,278,308
1.625% 10/31/26	81,936,000	85,351,067
1.625% 11/30/26	9,359,000	9,744,693
1.625% 8/15/29 (a)	131,397,000	135,210,593
1.75% 12/31/26	69,156,000	72,503,043
1.75% 11/15/29 (a)	71,816,000	74,576,428
1.875% 6/30/26	83,099,000	87,786,303
1.875% 7/31/26	51,781,000	54,699,749
2% 11/15/26	79,589,000	84,541,550
2.125% 5/31/26	55,935,000	59,826,415
2.25% 3/31/26	43,963,000	47,285,985
2.25% 2/15/27	105,827,000	113,983,120
2.25% 8/15/27	100,419,000	108,170,092
2.25% 11/15/27	141,887,000	152,783,479
2.375% 4/30/26	38,468,000	41,631,091
2.375% 5/15/27	102,312,000	111,032,500
2.375% 5/15/29	78,181,000	85,079,863
2.625% 2/15/29	117,274,000	129,816,820
2.75% 2/15/28	118,230,000	131,318,430
2.875% 5/15/28	109,820,000	123,105,646
2.875% 8/15/28	185,932,000	208,730,459
3.125% 11/15/28	165,551,000	189,103,216
		4,554,378,388
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $4,499,158,027)		4,554,378,388
	Shares	Value

Money Market Funds - 7.9%
Fidelity Cash Central Fund 0.07% (b)	11,348,279	$11,350,549
Fidelity Securities Lending Cash Central Fund 0.08% (b)(c)	347,308,844	347,343,575
TOTAL MONEY MARKET FUNDS
(Cost $358,694,124)		358,694,124
TOTAL INVESTMENT IN SECURITIES - 107.5%
(Cost $4,857,852,151)		4,913,072,512
NET OTHER ASSETS (LIABILITIES) - (7.5)%		(341,305,071)
NET ASSETS - 100%		$4,571,767,441

Legend

(a) Security or a portion of the security is on loan at period end.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$17,185
Fidelity Securities Lending Cash Central Fund	105,921
Total	$123,106

The value, beginning of period, for the Fidelity Securities Lending Cash Central Fund was $0. Net realized gain (loss) and change in net unrealized appreciation (depreciation) on Fidelity Securities Lending Cash Central Fund is presented in the Statement of Operations, if applicable. Purchases and sales of the Fidelity Securities Lending Cash Central Fund were $1,864,479,235 and $1,517,135,660, respectively, during the period.

Investment Valuation

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$4,554,378,388	$--	$4,554,378,388	$--
Money Market Funds	358,694,124	358,694,124	--	--
Total Investments in Securities:	$4,913,072,512	$358,694,124	$4,554,378,388	$--

See accompanying notes which are an integral part of the financial statements.

Fidelity® Intermediate Treasury Bond Index Fund

Financial Statements

Statement of Assets and Liabilities

		February 28, 2021
Assets
Investment in securities, at value (including securities loaned of $340,721,117) — See accompanying schedule: Unaffiliated issuers (cost $4,499,158,027)	$4,554,378,388
Fidelity Central Funds (cost $358,694,124)	358,694,124
Total Investment in Securities (cost $4,857,852,151)		$4,913,072,512
Receivable for investments sold		166,588,022
Receivable for fund shares sold		162,335,967
Interest receivable		14,153,918
Distributions receivable from Fidelity Central Funds		34,132
Total assets		5,256,184,551
Liabilities
Payable for investments purchased	$313,640,732
Payable for fund shares redeemed	22,896,571
Distributions payable	426,325
Accrued management fee	109,907
Collateral on securities loaned	347,343,575
Total liabilities		684,417,110
Net Assets		$4,571,767,441
Net Assets consist of:
Paid in capital		$4,485,844,185
Total accumulated earnings (loss)		85,923,256
Net Assets		$4,571,767,441
Net Asset Value, offering price and redemption price per share ($4,571,767,441 ÷ 401,751,690 shares)		$11.38

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended February 28, 2021
Investment Income
Interest (including $125,628 from security lending)		$63,167,899
Income from Fidelity Central Funds (including $105,921 from security lending)		123,106
Total income		63,291,005
Expenses
Management fee	$1,272,181
Independent trustees' fees and expenses	12,889
Miscellaneous	8,992
Total expenses before reductions	1,294,062
Expense reductions	(35)
Total expenses after reductions		1,294,027
Net investment income (loss)		61,996,978
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	108,903,757
Fidelity Central Funds	3,191
Total net realized gain (loss)		108,906,948
Change in net unrealized appreciation (depreciation) on:
Investment securities:
Unaffiliated issuers	(179,378,736)
Fidelity Central Funds	(3,827)
Total change in net unrealized appreciation (depreciation)		(179,382,563)
Net gain (loss)		(70,475,615)
Net increase (decrease) in net assets resulting from operations		$(8,478,637)

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended February 28, 2021	Year ended February 29, 2020
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$61,996,978	$62,687,750
Net realized gain (loss)	108,906,948	42,046,132
Change in net unrealized appreciation (depreciation)	(179,382,563)	239,277,074
Net increase (decrease) in net assets resulting from operations	(8,478,637)	344,010,956
Distributions to shareholders	(130,081,782)	(58,253,066)
Share transactions
Proceeds from sales of shares	4,173,652,409	2,037,746,906
Reinvestment of distributions	116,047,788	52,509,013
Cost of shares redeemed	(3,088,255,834)	(1,159,880,411)
Net increase (decrease) in net assets resulting from share transactions	1,201,444,363	930,375,508
Total increase (decrease) in net assets	1,062,883,944	1,216,133,398
Net Assets
Beginning of period	3,508,883,497	2,292,750,099
End of period	$4,571,767,441	$3,508,883,497
Other Information
Shares
Sold	351,520,038	184,099,152
Issued in reinvestment of distributions	9,845,238	4,717,754
Redeemed	(260,908,714)	(104,992,810)
Net increase (decrease)	100,456,562	83,824,096

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Intermediate Treasury Bond Index Fund


Years ended February 28,	2021	2020 ^A	2019	2018 ^B
Selected Per–Share Data
Net asset value, beginning of period	$11.65	$10.54	$10.37	$10.77
Income from Investment Operations
Net investment income (loss)^C	.174	.255	.258	.091
Net realized and unrealized gain (loss)	(.092)	1.092	.153	(.405)
Total from investment operations	.082	1.347	.411	(.314)
Distributions from net investment income	(.171)	(.237)	(.241)	(.086)
Distributions from net realized gain	(.181)	–	–	–
Total distributions	(.352)	(.237)	(.241)	(.086)
Net asset value, end of period	$11.38	$11.65	$10.54	$10.37
Total Return^D,^E	.63%	12.91%	4.02%	(2.94)%
Ratios to Average Net Assets^F,^G
Expenses before reductions	.03%	.03%	.03%	.03%^H
Expenses net of fee waivers, if any	.03%	.03%	.03%	.03%^H
Expenses net of all reductions	.03%	.03%	.03%	.03%^H
Net investment income (loss)	1.46%	2.30%	2.47%	2.12%^H
Supplemental Data
Net assets, end of period (000 omitted)	$4,571,767	$3,508,883	$2,292,750	$97,998
Portfolio turnover rate^I	56%	58%	65%	43%

^A For the year ended February 29.

^B For the period October 4, 2017 (commencement of sale of shares) to February 28, 2018.

^C Calculated based on average shares outstanding during the period.

^D Total returns for periods of less than one year are not annualized.

^E Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^H Annualized

^I Amount does not include the portfolio activity of any underlying mutual funds or exchange-traded funds (ETFs).

See accompanying notes which are an integral part of the financial statements.

Fidelity® Long-Term Treasury Bond Index Fund

Investment Summary (Unaudited)

Coupon Distribution as of February 28, 2021

	% of fund's investments
1 - 1.99%	20.3
2 - 2.99%	28.6
3 - 3.99%	39.1
4 - 4.99%	9.4
5 - 5.99%	0.1

Coupon distribution shows the range of stated interest rates on the fund's investments, excluding short-term investments.

Asset Allocation (% of fund's net assets)

As of February 28, 2021
	U.S. Treasury Obligations	99.5%
	Short-Term Investments and Net Other Assets (Liabilities)	0.5%

Fidelity® Long-Term Treasury Bond Index Fund

Schedule of Investments February 28, 2021

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.5%
	Principal Amount	Value
U.S. Treasury Obligations - 99.5%
U.S. Treasury Bonds:
1.125% 5/15/40	$103,659,000	$89,049,560
1.125% 8/15/40	115,320,000	98,634,638
1.25% 5/15/50	72,233,000	58,333,790
1.375% 11/15/40	111,895,000	100,076,091
1.375% 8/15/50	120,691,000	100,758,127
1.625% 11/15/50 (a)	122,684,000	109,092,911
1.875% 2/15/41	30,887,000	30,225,825
1.875% 2/15/51	39,050,000	36,975,469
2% 2/15/50	99,697,900	97,115,880
2.25% 8/15/46	39,736,000	40,824,083
2.25% 8/15/49	51,506,000	52,986,798
2.375% 11/15/49	80,158,000	84,710,724
2.5% 2/15/45	41,041,000	44,152,741
2.5% 2/15/46	43,795,000	47,130,947
2.5% 5/15/46	47,721,000	51,331,765
2.75% 8/15/42	10,986,000	12,373,412
2.75% 11/15/42	34,725,000	39,068,338
2.75% 8/15/47	55,842,000	63,169,081
2.75% 11/15/47	82,015,000	92,789,080
2.875% 5/15/43	36,441,000	41,880,104
2.875% 8/15/45	60,823,500	69,956,529
2.875% 11/15/46	31,934,000	36,840,110
2.875% 5/15/49	90,257,000	105,269,763
3% 5/15/42	44,632,000	52,252,565
3% 11/15/44	40,437,000	47,396,587
3% 5/15/45	44,173,000	51,875,667
3% 11/15/45	33,660,000	39,570,223
3% 2/15/47	73,091,000	86,364,440
3% 5/15/47	16,059,000	18,990,395
3% 2/15/48	80,797,000	95,801,255
3% 8/15/48	62,850,000	74,656,471
3% 2/15/49	68,647,000	81,730,153
3.125% 11/15/41	22,170,000	26,472,366
3.125% 2/15/42	20,406,000	24,370,822
3.125% 2/15/43	53,997,000	64,488,449
3.125% 8/15/44	34,718,300	41,514,136
3.125% 5/15/48	83,853,000	101,691,416
3.375% 5/15/44	10,474,300	13,014,727
3.375% 11/15/48	74,157,000	94,211,255
3.5% 2/15/39	10,281,000	12,881,772
3.625% 8/15/43	57,353,000	73,837,507
3.625% 2/15/44	51,004,000	65,755,313
3.75% 8/15/41	21,581,000	28,094,078
3.75% 11/15/43	58,468,000	76,675,301
3.875% 8/15/40	21,972,000	28,959,268
4.25% 5/15/39	9,981,000	13,686,056
4.25% 11/15/40	12,299,000	16,996,161
4.375% 2/15/38	6,210,000	8,568,587
4.375% 11/15/39	22,043,000	30,737,069
4.375% 5/15/40	23,064,000	32,277,888
4.375% 5/15/41	20,553,000	28,929,953
4.5% 2/15/36	30,010,000	41,252,027
4.5% 5/15/38	3,310,000	4,634,388
4.5% 8/15/39	13,889,000	19,622,553
4.625% 2/15/40	24,872,000	35,797,220
4.75% 2/15/37 (a)	10,664,000	15,163,708
4.75% 2/15/41	27,971,000	41,128,296
5% 5/15/37	2,509,000	3,665,198
		2,995,809,036
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $2,849,339,966)		2,995,809,036
	Shares	Value

Money Market Funds - 2.5%
Fidelity Cash Central Fund 0.07% (b)	19,146,657	$19,150,486
Fidelity Securities Lending Cash Central Fund 0.08% (b)(c)	55,943,736	55,949,330
TOTAL MONEY MARKET FUNDS
(Cost $75,099,816)		75,099,816
TOTAL INVESTMENT IN SECURITIES - 102.0%
(Cost $2,924,439,782)		3,070,908,852
NET OTHER ASSETS (LIABILITIES) - (2.0)%		(59,052,902)
NET ASSETS - 100%		$3,011,855,950

Legend

(a) Security or a portion of the security is on loan at period end.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$8,286
Fidelity Securities Lending Cash Central Fund	16,439
Total	$24,725

Investment Valuation

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$2,995,809,036	$--	$2,995,809,036	$--
Money Market Funds	75,099,816	75,099,816	--	--
Total Investments in Securities:	$3,070,908,852	$75,099,816	$2,995,809,036	$--

See accompanying notes which are an integral part of the financial statements.

Fidelity® Long-Term Treasury Bond Index Fund

Financial Statements

Statement of Assets and Liabilities

		February 28, 2021
Assets
Investment in securities, at value (including securities loaned of $55,781,421) — See accompanying schedule: Unaffiliated issuers (cost $2,849,339,966)	$2,995,809,036
Fidelity Central Funds (cost $75,099,816)	75,099,816
Total Investment in Securities (cost $2,924,439,782)		$3,070,908,852
Receivable for investments sold		41,221,265
Receivable for fund shares sold		22,536,210
Interest receivable		11,646,152
Distributions receivable from Fidelity Central Funds		4,433
Other receivables		61
Total assets		3,146,316,973
Liabilities
Payable for investments purchased	$67,045,539
Payable for fund shares redeemed	11,005,351
Distributions payable	383,977
Accrued management fee	76,826
Collateral on securities loaned	55,949,330
Total liabilities		134,461,023
Net Assets		$3,011,855,950
Net Assets consist of:
Paid in capital		$2,856,005,049
Total accumulated earnings (loss)		155,850,901
Net Assets		$3,011,855,950
Net Asset Value, offering price and redemption price per share ($3,011,855,950 ÷ 207,860,753 shares)		$14.49

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended February 28, 2021
Investment Income
Interest (including $14,093 from security lending)		$62,606,970
Income from Fidelity Central Funds (including $16,439 from security lending)		24,725
Total income		62,631,695
Expenses
Management fee	$909,891
Independent trustees' fees and expenses	9,328
Miscellaneous	6,513
Total expenses before reductions	925,732
Expense reductions	(530)
Total expenses after reductions		925,202
Net investment income (loss)		61,706,493
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	95,437,718
Fidelity Central Funds	2,991
Total net realized gain (loss)		95,440,709
Change in net unrealized appreciation (depreciation) on investment securities		(391,683,660)
Net gain (loss)		(296,242,951)
Net increase (decrease) in net assets resulting from operations		$(234,536,458)

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended February 28, 2021	Year ended February 29, 2020
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$61,706,493	$61,486,400
Net realized gain (loss)	95,440,709	88,210,415
Change in net unrealized appreciation (depreciation)	(391,683,660)	521,481,492
Net increase (decrease) in net assets resulting from operations	(234,536,458)	671,178,307
Distributions to shareholders	(122,730,741)	(60,275,278)
Share transactions
Proceeds from sales of shares	2,738,083,827	1,614,519,283
Reinvestment of distributions	112,319,394	55,064,909
Cost of shares redeemed	(2,172,490,128)	(1,955,319,533)
Net increase (decrease) in net assets resulting from share transactions	677,913,093	(285,735,341)
Total increase (decrease) in net assets	320,645,894	325,167,688
Net Assets
Beginning of period	2,691,210,056	2,366,042,368
End of period	$3,011,855,950	$2,691,210,056
Other Information
Shares
Sold	165,801,155	113,255,535
Issued in reinvestment of distributions	6,987,569	3,867,335
Redeemed	(132,076,926)	(138,776,901)
Net increase (decrease)	40,711,798	(21,654,031)

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Long-Term Treasury Bond Index Fund


Years ended February 28,	2021	2020 ^A	2019	2018 ^B
Selected Per–Share Data
Net asset value, beginning of period	$16.10	$12.53	$12.42	$13.06
Income from Investment Operations
Net investment income (loss)^C	.336	.378	.381	.136
Net realized and unrealized gain (loss)	(1.296)	3.562	.101	(.627)
Total from investment operations	(.960)	3.940	.482	(.491)
Distributions from net investment income	(.330)	(.370)	(.372)	(.149)
Distributions from net realized gain	(.320)	–	–	–
Total distributions	(.650)	(.370)	(.372)	(.149)
Net asset value, end of period	$14.49	$16.10	$12.53	$12.42
Total Return^D,^E	(6.32)%	31.86%	3.94%	(3.81)%
Ratios to Average Net Assets^F,^G
Expenses before reductions	.03%	.03%	.03%	.03%^H
Expenses net of fee waivers, if any	.03%	.03%	.03%	.03%^H
Expenses net of all reductions	.03%	.03%	.03%	.03%^H
Net investment income (loss)	2.04%	2.69%	3.04%	3.05%^H
Supplemental Data
Net assets, end of period (000 omitted)	$3,011,856	$2,691,210	$2,366,042	$314,669
Portfolio turnover rate^I	41%	54%	34%	24%

^A For the year ended February 29.

^B For the period October 4, 2017 (commencement of sale of shares) to February 28, 2018.

^C Calculated based on average shares outstanding during the period.

^D Total returns for periods of less than one year are not annualized.

^E Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^H Annualized

^I Amount does not include the portfolio activity of any underlying mutual funds or exchange-traded funds (ETFs).

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended February 28, 2021

1. Organization.

Fidelity Short-Term Treasury Bond Index Fund, Fidelity Intermediate Treasury Bond Index Fund and Fidelity Long-Term Treasury Bond Index Fund (the Funds) are funds of Fidelity Salem Street Trust (the Trust). Each Fund is authorized to issue an unlimited number of shares. Share transactions on the Statement of Changes in Net Assets may contain exchanges between affiliated funds. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Massachusetts business trust.

2. Investments in Fidelity Central Funds.

The Funds invest in Fidelity Central Funds, which are open-end investment companies generally available only to other investment companies and accounts managed by the investment adviser and its affiliates. The Funds' Schedules of Investments list each of the Fidelity Central Funds held as of period end, if any, as an investment of each Fund, but do not include the underlying holdings of each Fidelity Central Fund. As an Investing Fund, each Fund indirectly bears its proportionate share of the expenses of the underlying Fidelity Central Funds.

A complete unaudited list of holdings for each Fidelity Central Fund is available upon request or at the Securities and Exchange Commission (the SEC) website at www.sec.gov. In addition, the financial statements of the Fidelity Central Funds, which are not covered by the Funds' Report of Independent Registered Public Accounting Firm, are available on the SEC website or upon request.

3. Significant Accounting Policies.

Each Fund is an investment company and applies the accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services - Investment Companies. The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP), which require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from those estimates. Subsequent events, if any, through the date that the financial statements were issued have been evaluated in the preparation of the financial statements. The following summarizes the significant accounting policies of the Funds:

Investment Valuation. Investments are valued as of 4:00 p.m. Eastern time on the last calendar day of the period. The Board of Trustees (the Board) has delegated the day to day responsibility for the valuation of each Fund's investments to the Fair Value Committee (the Committee) established by each Fund's investment adviser. In accordance with valuation policies and procedures approved by the Board, each Fund attempts to obtain prices from one or more third party pricing vendors or brokers to value its investments. When current market prices, quotations or currency exchange rates are not readily available or reliable, investments will be fair valued in good faith by the Committee, in accordance with procedures adopted by the Board. Factors used in determining fair value vary by investment type and may include market or investment specific events, changes in interest rates and credit quality. The frequency with which these procedures are used cannot be predicted and they may be utilized to a significant extent. The Committee oversees each Fund's valuation policies and procedures and reports to the Board on the Committee's activities and fair value determinations. The Board monitors the appropriateness of the procedures used in valuing each Fund's investments and ratifies the fair value determinations of the Committee.

Each Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Valuation techniques used to value each Fund's investments by major category are as follows:

Debt securities, including restricted securities, are valued based on evaluated prices received from third party pricing vendors or from brokers who make markets in such securities. U.S. government and government agency obligations are valued by pricing vendors who utilize matrix pricing which considers yield or price of bonds of comparable quality, coupon, maturity and type or by broker-supplied prices. When independent prices are unavailable or unreliable, debt securities may be valued utilizing pricing methodologies which consider similar factors that would be used by third party pricing vendors. Debt securities are generally categorized as Level 2 in the hierarchy but may be Level 3 depending on the circumstances.

Investments in open-end mutual funds, including the Fidelity Central Funds, are valued at their closing net asset value (NAV) each business day and are categorized as Level 1 in the hierarchy.

Investment Transactions and Income. For financial reporting purposes, the Funds' investment holdings and NAV include trades executed through the end of the last business day of the period. The NAV per share for processing shareholder transactions is calculated as of the close of business of the New York Stock Exchange (NYSE), normally 4:00 p.m. Eastern time and includes trades executed through the end of the prior business day. Gains and losses on securities sold are determined on the basis of identified cost and for certain Funds include proceeds received from litigation. Income and capital gain distributions from Fidelity Central Funds, if any, are recorded on the ex-dividend date. Interest income is accrued as earned and includes coupon interest and amortization of premium and accretion of discount on debt securities as applicable.

Income Tax Information and Distributions to Shareholders. Each year, each Fund intends to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code, including distributing substantially all of its taxable income and realized gains. As a result, no provision for U.S. Federal income taxes is required. As of February 28, 2021, each Fund did not have any unrecognized tax benefits in the financial statements; nor is each Fund aware of any tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. Each Fund files a U.S. federal tax return, in addition to state and local tax returns as required. Each Fund's federal income tax returns are subject to examination by the Internal Revenue Service (IRS) for a period of three fiscal years after they are filed. State and local tax returns may be subject to examination for an additional fiscal year depending on the jurisdiction.

Distributions are declared and recorded daily and paid monthly from net investment income. Distributions from realized gains, if any, are declared and recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. In addition, the Funds claimed a portion of the payment made to redeeming shareholders as a distribution for income tax purposes.

Book-tax differences are primarily due to market discount, capital loss carryforwards and losses deferred due to wash sales and excise tax regulations.

As of period end, the cost and unrealized appreciation (depreciation) in securities, and derivatives if applicable, for federal income tax purposes were as follows for each Fund:

	Tax cost	Gross unrealized appreciation	Gross unrealized depreciation	Net unrealized appreciation (depreciation)
Fidelity Short-Term Treasury Bond Index Fund	$3,860,688,791	$64,545,431	$(11,349,221)	$53,196,210
Fidelity Intermediate Treasury Bond Index Fund	4,854,586,899	139,876,032	(81,390,419)	58,485,613
Fidelity Long-Term Treasury Bond Index Fund	2,924,108,983	286,769,320	(139,969,451)	146,799,869

The tax-based components of distributable earnings as of period end were as follows for each Fund:

	Undistributed ordinary income	Undistributed long-term capital gain	Net unrealized appreciation (depreciation) on securities and other investments
Fidelity Short-Term Treasury Bond Index Fund	$516,648	$8,481,113	$53,196,210
Fidelity Intermediate Treasury Bond Index Fund	975,948	26,461,694	58,485,613
Fidelity Long-Term Treasury Bond Index Fund	–	10,714,231	146,799,869

Certain of the Funds intend to elect to defer to the next fiscal year capital losses recognized during the period November 1, 2020 to February 28, 2021. Loss deferrals were as follows:

	Capital losses
Fidelity Long-Term Treasury Bond Index Fund	(1,057,397)

The tax character of distributions paid was as follows:

February 28, 2021
	Ordinary Income	Long-term Capital Gains	Total
Fidelity Short-Term Treasury Bond Index Fund	$46,640,110	$5,820,851	$52,460,961
Fidelity Intermediate Treasury Bond Index Fund	77,306,095	52,775,687	130,081,782
Fidelity Long-Term Treasury Bond Index Fund	65,055,256	57,675,485	122,730,741

February 28, 2020
	Ordinary Income	Total
Fidelity Short-Term Treasury Bond Index Fund	$41,722,112	$41,722,112
Fidelity Intermediate Treasury Bond Index Fund	58,253,066	58,253,066
Fidelity Long-Term Treasury Bond Index Fund	60,275,278	60,275,278

4. Fees and Other Transactions with Affiliates.

Management Fee. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Funds with investment management related services for which the Funds pay a monthly management fee. The management fee is based on an annual rate of .03% of each Fund's average net assets. Under the management contract, the investment adviser pays all other operating expenses, except the compensation of the independent Trustees and certain other expenses such as interest expense.

5. Committed Line of Credit.

	Amount
Fidelity Short-Term Treasury Bond Index Fund	$7,573
Fidelity Intermediate Treasury Bond Index Fund	8,992
Fidelity Long-Term Treasury Bond Index Fund	6,513

During the period, there were no borrowings on this line of credit.

6. Security Lending.

Funds lend portfolio securities from time to time in order to earn additional income. Lending agents are used, including National Financial Services (NFS), an affiliate of the investment adviser. Pursuant to a securities lending agreement, NFS will receive a fee, which is capped at 9.9% of a fund's daily lending revenue, for its services as lending agent. A fund may lend securities to certain qualified borrowers, including NFS. On the settlement date of the loan, a fund receives collateral (in the form of U.S. Treasury obligations, letters of credit and/or cash) against the loaned securities and maintains collateral in an amount not less than 100% of the market value of the loaned securities during the period of the loan. The market value of the loaned securities is determined at the close of business of a fund and any additional required collateral is delivered to a fund on the next business day. A fund or borrower may terminate the loan at any time, and if the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund may apply collateral received from the borrower against the obligation. A fund may experience delays and costs in recovering the securities loaned. Any cash collateral received is invested in the Fidelity Securities Lending Cash Central Fund. Any loaned securities are identified as such in the Schedule of Investments, and the value of loaned securities and cash collateral at period end, as applicable, are presented in the Statement of Assets and Liabilities. Security lending income represents the income earned on investing cash collateral, less rebates paid to borrowers and any lending agent fees associated with the loan, plus any premium payments received for lending certain types of securities. Security lending income is presented in the Statement of Operations as a component of interest income and as a component of income from Fidelity Central Funds. Affiliated security lending activity, if any, was as follows:

	Total Security Lending Income Fees Paid to NFS	Security Lending Income From Securities Loaned to NFS	Value of Securities Loaned to NFS at Period End
Fidelity Short-Term Treasury Bond Index Fund	$1,617	$–	$–
Fidelity Intermediate Treasury Bond Index Fund	$12,013	$–	$–
Fidelity Long-Term Treasury Bond Index Fund	$1,782	$–	$–

7. Expense Reductions.

Through arrangements with each applicable Fund's custodian, credits realized as a result of certain uninvested cash balances were used to reduce each applicable Fund's expenses. All of the applicable expense reductions are noted in the table below.

	Custodian credits
Fidelity Short-Term Treasury Bond Index Fund	$329
Fidelity Intermediate Treasury Bond Index Fund	35
Fidelity Long-Term Treasury Bond Index Fund	530

8. Other.

The Funds' organizational documents provide former and current trustees and officers with a limited indemnification against liabilities arising in connection with the performance of their duties to the Funds. In the normal course of business, the Funds may also enter into contracts that provide general indemnifications. The Funds' maximum exposure under these arrangements is unknown as this would be dependent on future claims that may be made against the Funds. The risk of material loss from such claims is considered remote.

9. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Salem Street Trust and the Shareholders of Fidelity Short-Term Treasury Bond Index Fund, Fidelity Intermediate Treasury Bond Index Fund and Fidelity Long-Term Treasury Bond Index Fund

Opinions on the Financial Statements

We have audited the accompanying statements of assets and liabilities, including the schedules of investments, of Fidelity Short-Term Treasury Bond Index Fund, Fidelity Intermediate Treasury Bond Index Fund and Fidelity Long-Term Treasury Bond Index Fund (three of the funds constituting Fidelity Salem Street Trust, hereafter collectively referred to as the “Funds”) as of February 28, 2021, the related statements of operations for the year ended February 28, 2021, the statements of changes in net assets for each of the two years in the period ended February 28, 2021, including the related notes, and the financial highlights for each of the three years in the period ended February 28, 2021 and for the period October 4, 2017 (commencement of operations) through February 28, 2018 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Funds as of February 28, 2021, the results of each of their operations for the year then ended, the changes in each of their net assets for each of the two years in the period ended February 28, 2021 and each of the financial highlights for each of the three years in the period ended February 28, 2021 and for the period October 4, 2017 (commencement of operations) through February 28, 2018 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinions

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

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of February 28, 2021 by correspondence with the custodians and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinions.

/s/ PricewaterhouseCoopers LLP

Boston, Massachusetts

April 13, 2021

We have served as the auditor of one or more investment companies in the Fidelity group of funds since 1932.

Trustees and Officers

The Trustees, Members of the Advisory Board (if any), and officers of the trust and funds, as applicable, are listed below. The Board of Trustees governs each fund and is responsible for protecting the interests of shareholders. The Trustees are experienced executives who meet periodically throughout the year to oversee each fund's activities, review contractual arrangements with companies that provide services to each fund, oversee management of the risks associated with such activities and contractual arrangements, and review each fund's performance. Except for Jonathan Chiel, each of the Trustees oversees 282 funds. Mr. Chiel oversees 176 funds.

The Trustees hold office without limit in time except that (a) any Trustee may resign; (b) any Trustee may be removed by written instrument, signed by at least two-thirds of the number of Trustees prior to such removal; (c) any Trustee who requests to be retired or who has become incapacitated by illness or injury may be retired by written instrument signed by a majority of the other Trustees; and (d) any Trustee may be removed at any special meeting of shareholders by a two-thirds vote of the outstanding voting securities of the trust. Each Trustee who is not an interested person (as defined in the 1940 Act) of the trust and the funds is referred to herein as an Independent Trustee. Each Independent Trustee shall retire not later than the last day of the calendar year in which his or her 75th birthday occurs. The Independent Trustees may waive this mandatory retirement age policy with respect to individual Trustees. Officers and Advisory Board Members hold office without limit in time, except that any officer or Advisory Board Member may resign or may be removed by a vote of a majority of the Trustees at any regular meeting or any special meeting of the Trustees. Except as indicated, each individual has held the office shown or other offices in the same company for the past five years.

Each fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-8544.

In determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, qualifications, attributes, and skills, which allow the Board to operate effectively in governing each fund and protecting the interests of shareholders. Information about the specific experience, skills, attributes, and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a trustee of the funds, is provided below.

Board Structure and Oversight Function. Abigail P. Johnson is an interested person and currently serves as Chairman. The Trustees have determined that an interested Chairman is appropriate and benefits shareholders because an interested Chairman has a personal and professional stake in the quality and continuity of services provided to the funds. Independent Trustees exercise their informed business judgment to appoint an individual of their choosing to serve as Chairman, regardless of whether the Trustee happens to be independent or a member of management. The Independent Trustees have determined that they can act independently and effectively without having an Independent Trustee serve as Chairman and that a key structural component for assuring that they are in a position to do so is for the Independent Trustees to constitute a substantial majority for the Board. The Independent Trustees also regularly meet in executive session. Arthur E. Johnson serves as Chairman of the Independent Trustees and as such (i) acts as a liaison between the Independent Trustees and management with respect to matters important to the Independent Trustees and (ii) with management prepares agendas for Board meetings.

Fidelity^® funds are overseen by different Boards of Trustees. The funds' Board oversees Fidelity's investment-grade bond, money market, asset allocation and certain equity funds, and other Boards oversee Fidelity's high income and other equity funds. The asset allocation funds may invest in Fidelity^® funds that are overseen by such other Boards. The use of separate Boards, each with its own committee structure, allows the Trustees of each group of Fidelity^® funds to focus on the unique issues of the funds they oversee, including common research, investment, and operational issues. On occasion, the separate Boards establish joint committees to address issues of overlapping consequences for the Fidelity^® funds overseen by each Board.

The Trustees operate using a system of committees to facilitate the timely and efficient consideration of all matters of importance to the Trustees, each fund, and fund shareholders and to facilitate compliance with legal and regulatory requirements and oversight of the funds' activities and associated risks. The Board, acting through its committees, has charged FMR and its affiliates with (i) identifying events or circumstances the occurrence of which could have demonstrably adverse effects on the funds' business and/or reputation; (ii) implementing processes and controls to lessen the possibility that such events or circumstances occur or to mitigate the effects of such events or circumstances if they do occur; and (iii) creating and maintaining a system designed to evaluate continuously business and market conditions in order to facilitate the identification and implementation processes described in (i) and (ii) above. Because the day-to-day operations and activities of the funds are carried out by or through FMR, its affiliates, and other service providers, the funds' exposure to risks is mitigated but not eliminated by the processes overseen by the Trustees. While each of the Board's committees has responsibility for overseeing different aspects of the funds' activities, oversight is exercised primarily through the Operations and Audit Committees. In addition, an ad hoc Board committee of Independent Trustees has worked with FMR to enhance the Board's oversight of investment and financial risks, legal and regulatory risks, technology risks, and operational risks, including the development of additional risk reporting to the Board. Appropriate personnel, including but not limited to the funds' Chief Compliance Officer (CCO), FMR's internal auditor, the independent accountants, the funds' Treasurer and portfolio management personnel, make periodic reports to the Board's committees, as appropriate, including an annual review of Fidelity's risk management program for the Fidelity^® funds. The responsibilities of each standing committee, including their oversight responsibilities, are described further under "Standing Committees of the Trustees."

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Jonathan Chiel (1957)

Year of Election or Appointment: 2016

Trustee

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Jamie Pagliocco (1964)

Year of Election or Appointment: 2020

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Brett Segaloff (1972)

Year of Election or Appointment: 2021

Anti-Money Laundering (AML) Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (September 1, 2020 to February 28, 2021).

Actual Expenses

Hypothetical Example for Comparison Purposes

	Annualized Expense Ratio-^A	Beginning Account Value September 1, 2020	Ending Account Value February 28, 2021	Expenses Paid During Period-^B September 1, 2020 to February 28, 2021
Fidelity Short-Term Treasury Bond Index Fund	.03%
Actual		$1,000.00	$996.70	$.15
Hypothetical-^C		$1,000.00	$1,024.65	$.15
Fidelity Intermediate Treasury Bond Index Fund	.03%
Actual		$1,000.00	$966.90	$.15
Hypothetical-^C		$1,000.00	$1,024.65	$.15
Fidelity Long-Term Treasury Bond Index Fund	.03%
Actual		$1,000.00	$890.40	$.14
Hypothetical-^C		$1,000.00	$1,024.65	$.15

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^C 5% return per year before expenses

Distributions (Unaudited)

The Board of Trustees of each fund voted to pay to shareholders of record at the opening of business on record date, the following distributions per share derived from capital gains realized from sales of portfolio securities:

	Pay Date	Record Date	Capital Gains
Fidelity Short-Term Treasury Bond Index Fund	04/12/21	04/09/21	$0.026
Fidelity Intermediate Treasury Bond Index Fund	04/12/21	04/09/21	$0.070
Fidelity Long-Term Treasury Bond Index Fund	04/12/21	04/09/21	$0.053

The funds hereby designate as capital gain dividend the amounts noted below for the taxable year ended February 28, 2021, or, if subsequently determined to be different, the net capital gain of such year.

Fidelity Short-Term Treasury Bond Index Fund	$14,374,436
Fidelity Intermediate Treasury Bond Index Fund	$88,160,693
Fidelity Long-Term Treasury Bond Index Fund	$84,389,508

A percentage of the dividends distributed during the fiscal year for the following funds were derived from interest on U.S. Government securities which is generally exempt from state income tax:

Fidelity Short-Term Treasury Bond Index Fund	99.89%
Fidelity Intermediate Treasury Bond Index Fund	99.62%
Fidelity Long-Term Treasury Bond Index Fund	99.94%

The funds hereby designate the amounts noted below as distributions paid in the calendar year 2020 as qualifying to be taxed as interest-related dividends for nonresident alien shareholders:

Fidelity Short-Term Treasury Bond Index Fund	$ 43,204,140.57
Fidelity Intermediate Treasury Bond Index Fund	$ 61,482,539.36
Fidelity Long-Term Treasury Bond Index Fund	$ 59,667,062.99

The funds hereby designate the percentages noted below of the short-term capital gain dividends distributed during the fiscal year as qualifying to be taxed as short-term capital gain dividends for nonresident alien shareholders:

	April, 2020	December, 2020
Fidelity Short-Term Treasury Bond Index Fund	–	100.00%
Fidelity Intermediate Treasury Bond Index Fund	90.90%	100.00%
Fidelity Long-Term Treasury Bond Index Fund	–	100.00%

The funds hereby designate the amounts noted below as distributions paid in the calendar year 2020 as qualifying to be taxed as section 163(j) interest dividends:

Fidelity Short-Term Treasury Bond Index Fund	$ 43,448,302
Fidelity Intermediate Treasury Bond Index Fund	$ 62,096,670
Fidelity Long-Term Treasury Bond Index Fund	$ 59,747,105

The funds will notify shareholders in January 2022 of amounts for use in preparing 2021 income tax returns.

Board Approval of Investment Advisory Contracts and Management Fees

Fidelity Intermediate Treasury Bond Index Fund
Fidelity Long-Term Treasury Bond Index Fund
Fidelity Short-Term Treasury Bond Index Fund

Each year, the Board of Trustees, including the Independent Trustees (together, the Board), votes on the renewal of the management contract with Fidelity Management & Research Company LLC (FMR) and the sub-advisory agreements (together, the Advisory Contracts) for each fund. FMR and the sub-advisers are referred to herein as the Investment Advisers. The Board, assisted by the advice of fund counsel and Independent Trustees' counsel, requests and considers a broad range of information relevant to the renewal of the Advisory Contracts throughout the year.

The Board meets regularly and, at each of its meetings, covers an extensive agenda of topics and materials and considers factors that are relevant to its annual consideration of the renewal of each fund's Advisory Contracts, including the services and support provided to each fund and its shareholders. The Board has established four standing committees (Committees) — Operations, Audit, Fair Valuation, and Governance and Nominating — each composed of and chaired by Independent Trustees with varying backgrounds, to which the Board has assigned specific subject matter responsibilities in order to enhance effective decision-making by the Board. The Operations Committee, of which all of the Independent Trustees are members, meets regularly throughout the year and considers, among other matters, information specifically related to the annual consideration of the renewal of each fund's Advisory Contracts. The Board, acting directly and through its Committees, requests and receives information concerning the annual consideration of the renewal of each fund's Advisory Contracts. The Board also meets as needed to review matters specifically related to the Board's annual consideration of the renewal of the Advisory Contracts. Members of the Board may also meet with trustees of other Fidelity funds through joint ad hoc committees to discuss certain matters relevant to all of the Fidelity funds.

At its September 2020 meeting, the Board unanimously determined to renew each fund's Advisory Contracts. In reaching its determination, the Board considered all factors it believed relevant, including (i) the nature, extent, and quality of the services provided to each fund and its shareholders (including the investment performance of each fund); (ii) the competitiveness of each fund's management fee and total expense ratio relative to peer funds; (iii) the total costs of the services provided by and the profits realized by Fidelity from its relationships with each fund; and (iv) the extent to which, if any, economies of scale exist and are realized as each fund grows, and whether any economies of scale are appropriately shared with fund shareholders.

In considering whether to renew the Advisory Contracts for each fund, the Board reached a determination, with the assistance of fund counsel and Independent Trustees' counsel and through the exercise of its business judgment, that the renewal of the Advisory Contracts was in the best interests of each fund and its shareholders and that the compensation payable under the Advisory Contracts was fair and reasonable. The Board's decision to renew the Advisory Contracts was not based on any single factor, but rather was based on a comprehensive consideration of all the information provided to the Board at its meetings throughout the year. The Board, in reaching its determination to renew the Advisory Contracts, was aware that shareholders of each fund have a broad range of investment choices available to them, including a wide choice among funds offered by Fidelity's competitors, and that each fund's shareholders, who have the opportunity to review and weigh the disclosure provided by the fund in its prospectus and other public disclosures, have chosen to invest in that fund, which is part of the Fidelity family of funds.

Nature, Extent, and Quality of Services Provided. The Board considered Fidelity's staffing as it relates to the funds, including the backgrounds of investment personnel of Fidelity, and also considered the funds' investment objectives, strategies, and related investment philosophies. The Independent Trustees also had discussions with senior management of Fidelity's investment operations and investment groups. The Board considered the structure of the investment personnel compensation program and whether this structure provides appropriate incentives to act in the best interests of each fund. Additionally, the Board considered the portfolio managers' investments, if any, in the funds that they manage.

Resources Dedicated to Investment Management and Support Services. The Board reviewed the general qualifications and capabilities of Fidelity's investment staff, including its size, education, experience, and resources, as well as Fidelity's approach to recruiting, managing, and compensating investment personnel. The Board noted that Fidelity has continued to increase the resources devoted to non-U.S. offices, including expansion of Fidelity's global investment organization. The Board also noted that Fidelity's analysts have extensive resources, tools and capabilities that allow them to conduct sophisticated quantitative and fundamental analysis, as well as credit analysis of issuers, counterparties and guarantors. Further, the Board considered that Fidelity's investment professionals have sufficient access to global information and data so as to provide competitive investment results over time, and that those professionals also have access to sophisticated tools that permit them to assess portfolio construction and risk and performance attribution characteristics continuously, as well as to transmit new information and research conclusions rapidly around the world. Additionally, in its deliberations, the Board considered Fidelity's trading, risk management, compliance, and technology and operations capabilities and resources, which are integral parts of the investment management process. The Board also considered Fidelity's investments in business continuity planning, and its success in continuously providing services to the funds notwithstanding the severe disruptions caused by the COVID-19 pandemic.

Shareholder and Administrative Services. The Board considered (i) the nature, extent, quality, and cost of advisory, administrative, and shareholder services performed by the Investment Advisers and their affiliates under the Advisory Contracts and under separate agreements covering transfer agency, pricing and bookkeeping, and securities lending services for each fund; (ii) the nature and extent of the supervision of third party service providers, principally custodians, subcustodians, and pricing vendors; and (iii) the resources devoted to, and the record of compliance with, each fund's compliance policies and procedures.

Investment Performance. The Board considered whether each fund has operated in accordance with its investment objective, as well as its record of compliance with its investment restrictions and its performance history.

The Board took into account discussions that occur at Board meetings throughout the year with representatives of the Investment Advisers about fund investment performance. In this regard the Board noted that as part of regularly scheduled fund reviews and other reports to the Board on fund performance, the Board considers annualized return information for each fund for different time periods, measured against the securities market index the fund seeks to track and an appropriate peer group of funds with similar objectives (peer group). The Board also periodically considers each fund's tracking error versus its benchmark index. In its evaluation of fund investment performance at meetings throughout the year, the Board gave particular attention to information indicating underperformance of certain Fidelity funds for specific time periods and discussed with the Investment Advisers the reasons for such underperformance.

The Independent Trustees recognize that shareholders evaluate performance on a net basis (after fees and expenses) over their own holding periods, for which one-, three-, and five-year periods are often used as a proxy. For this reason, the performance information reviewed by the Board also included net cumulative calendar year total return information for each fund and its benchmark index and peer group for the most recent one-, three-, and five-year periods. The Independent Trustees recognize that shareholders who are not investing through a tax-advantaged retirement account also consider tax consequences in evaluating performance.

Based on its review, the Board concluded that the nature, extent, and quality of services provided to each fund under the Advisory Contracts should continue to benefit the shareholders of each fund.

Competitiveness of Management Fee and Total Expense Ratio. The Board considered each fund's management fee and total expense ratio compared to "mapped groups" of competitive funds and classes created for the purpose of facilitating the Trustees' competitive analysis of management fees and total expenses. Fidelity creates "mapped groups" by combining similar Lipper investment objective categories that have comparable investment mandates. Combining Lipper investment objective categories aids the Board's management fee and total expense ratio comparisons by broadening the competitive group used for comparison.

Management Fee. The Board considered two proprietary management fee comparisons forthe 12-month periods shown in basis points (BP) in the charts below. The group of Lipper funds used by the Board for management fee comparisons is referred to below as the "Total Mapped Group" and is broader than the Lipper peer group used by the Board for performance comparisons. The Total Mapped Group comparison focuses on a fund's standing in terms of gross management fees before expense reimbursements or caps relative to the total universe of funds with comparable investment mandates, regardless of whether their management fee structures also are comparable. Funds with comparable investment mandates offer exposure to similar types of securities. Funds with comparable management fee structures have similar management fee contractual arrangements (e.g., flat rate charged for advisory services, all-inclusive fee rate, etc.). "TMG %" represents the percentage of funds in the Total Mapped Group that had management fees that were lower than a fund's. For example, a hypothetical TMG % of 20% would mean that 80% of the funds in the Total Mapped Group had higher, and 20% had lower, management fees than a fund. The funds' actual TMG %s and the number of funds in the Total Mapped Group are in the charts below. The "Asset-Sized Peer Group" (ASPG) comparison focuses on a fund's standing relative to a subset of non-Fidelity funds within the Total Mapped Group that are similar in size and management fee structure. For example, if a fund is in the first quartile of the ASPG, the fund's management fee ranks in the least expensive or lowest 25% of funds in the ASPG. The ASPG represents at least 15% of the funds in the Total Mapped Group with comparable asset size and management fee structures, subject to a minimum of 50 funds (or all funds in the Total Mapped Group if fewer than 50). Additional information, such as the ASPG quartile in which a fund's management fee rate ranked, is also included in the charts and was considered by the Board. Because the vast majority of competitor funds' management fees do not cover non-management expenses, in prior years, each fund was compared on the basis of a hypothetical "net management fee," which was derived by subtracting payments made by Fidelity for "fund-level" non-management expenses (including pricing and bookkeeping fees and fees paid to non-affiliated custodians), as well as "class-level" expenses paid by Fidelity under expense limitation arrangements then in effect for the fund, from the fund's management fee. Given the funds' competitive management fee rates, Fidelity no longer calculates hypothetical net management fees for the funds and, as a result, the charts do not include hypothetical net management fees for periods after 2015. With respect to the historical net management fee information, the Board considered that "fund-level" non-management expenses and "class-level" expenses paid by FMR may exceed a fund's management fee and result in a negative net management fee. The Board noted that a hypothetical net management fee is truly a hypothetical number derived for purposes of providing a more meaningful competitive comparison and a negative net management fee is not intended to suggest that Fidelity pays a fund to manage the fund's assets.

Fidelity Intermediate Treasury Bond Index Fund

The Board considered that effective August 1, 2017, the fund's management fee rate was reduced from 0.05% to 0.03%. The Board considered that the chart below reflects the fund's lower management fee rate for 2017, as if the lower fee rate were in effect for the entire year.

The Board noted that the fund's management fee rate ranked below the median of its Total Mapped Group and below the median of its ASPG for 2019.

Fidelity Long-Term Treasury Bond Index Fund

The Board noted that the fund’s management fee rate ranked below the median of its Total Mapped Group and below the median of its ASPG for 2019.

Fidelity Short-Term Treasury Bond Index Fund

The Board noted that the fund’s management fee rate ranked below the median of its Total Mapped Group and below the median of its ASPG for 2019.

The Board noted that it and the boards of other Fidelity funds formed an ad hoc Committee on Group Fee, which meets periodically, to conduct an in-depth review of the "group fee" component of the management fee of funds with such management fee structures. The Committee's focus included the mechanics of the group fee, the competitive landscape of group fee structures, Fidelity funds with no group fee component (such as the funds) and investment products not included in group fee assets. The Board also considered that, for funds subject to the group fee, FMR agreed to voluntarily waive fees over a specified period of time in amounts designed to account for assets converted from certain funds to certain collective investment trusts.

Based on its review, the Board concluded that each fund's management fee is fair and reasonable in light of the services that the fund receives and the other factors considered.

Total Expense Ratio. In its review of each fund's total expense ratio, the Board considered the fund's unitary fee rate as well as fund expenses paid by FMR under the fund's management contract, such as transfer agent fees, pricing and bookkeeping fees, and custodial, legal, and audit fees. The Board also noted that Fidelity may agree to waive fees or reimburse expenses from time to time, and the extent to which, if any, it has done so for each fund. As part of its review, the Board also considered the current and historical total expense ratios of each fund compared to competitive fund median expenses. Each fund is compared to those funds and classes in the Total Mapped Group (used by the Board for management fee comparisons) that have a similar sales load structure.

The Board noted that each fund's total expense ratio ranked below the competitive median for 2019.

Based on its review of total expense ratios and fees charged to other Fidelity clients, the Board concluded that each fund's total expense ratio was reasonable in light of the services that the fund and its shareholders receive and the other factors considered.

Costs of the Services and Profitability. The Board consideredthe revenues earned and the expenses incurred by Fidelity in conducting the business of developing, marketing, distributing, managing, administering and servicing each fund and servicing each fund's shareholders. The Board also considered the level of Fidelity's profits in respect of all the Fidelity funds.

On an annual basis, Fidelity presents to the Board information about the profitability of its relationships with each fund. Fidelity calculates profitability information for each fund, as well as aggregate profitability information for groups of Fidelity funds and all Fidelity funds, using a series of detailed revenue and cost allocation methodologies which originate with the books and records of Fidelity on which Fidelity's audited financial statements are based. The Audit Committee of the Board reviews any significant changes from the prior year's methodologies and the full Board approves such changes.

The Board considered the costs of the services provided by and the profits realized by Fidelity in connection with the operation of each fund, including the conclusions of the PFOB Committee, and was satisfied that the profitability was not excessive.

Economies of Scale. The Board considered whether there have been economies of scale in respect of the management of the Fidelity funds, whether the Fidelity funds (including each fund) have appropriately benefited from any such economies of scale, and whether there is potential for realization of any further economies of scale. The Board considered the extent to which each fund will benefit from economies of scale as assets grow through increased services to the fund, through waivers or reimbursements, or through fee or expense ratio reductions. The Board recognized that, due to each fund's current contractual arrangements, its expense ratio will not decline if the fund's operating costs decrease as assets grow, or rise as assets decrease. The Board also noted that a committee (the Economies of Scale Committee) created by it and the boards of other Fidelity funds periodically analyzes whether Fidelity attains economies of scale in respect of the management and servicing of the Fidelity funds, whether the Fidelity funds have appropriately benefited from such economies of scale, and whether there is potential for realization of any further economies of scale.

The Board concluded, taking into account the analysis of the Economies of Scale Committee, that economies of scale, if any, are being appropriately shared between fund shareholders and Fidelity.

Liquidity Risk Management Program

The Funds have adopted and implemented a liquidity risk management program pursuant to the Liquidity Rule (the Program) effective December 1, 2018. The Program is reasonably designed to assess and manage each Fund’s liquidity risk and to comply with the requirements of the Liquidity Rule. Each Fund’s Board of Trustees (the Board) has designated each Fund’s investment adviser as administrator of the Program. The Fidelity advisers have established a Liquidity Risk Management Committee (the LRM Committee) to manage the Program for each of the Fidelity Funds. The LRM Committee monitors the adequacy and effectiveness of implementation of the Program and on a periodic basis assesses each Fund’s liquidity risk based on a variety of factors including (1) the Fund’s investment strategy, (2) portfolio liquidity and cash flow projections during normal and reasonably foreseeable stressed conditions, (3) shareholder redemptions, (4) borrowings and other funding sources and (5) in the case of exchange-traded funds, certain additional factors including the effect of the Fund’s prices and spreads, market participants, and basket compositions on the overall liquidity of the Fund’s portfolio, as applicable.

Highly liquid investments – cash or convertible to cash within three business days or less
Moderately liquid investments – convertible to cash in three to seven calendar days
Less liquid investments – can be sold or disposed of, but not settled, within seven calendar days
Illiquid investments – cannot be sold or disposed of within seven calendar days

Fidelity Investments

LBX-I-ANN-0421
1.9885078.103

Item 2.

Code of Ethics

As of the end of the period, February 28, 2021, Fidelity Salem Street Trust (the trust) has adopted a code of ethics, as defined in Item 2 of Form N-CSR, that applies to its President and Treasurer and its Chief Financial Officer. A copy of the code of ethics is filed as an exhibit to this Form N-CSR.

Item 3.

Audit Committee Financial Expert

The Board of Trustees of the trust has determined that Elizabeth S. Acton is an audit committee financial expert, as defined in Item 3 of Form N-CSR. Ms. Acton is independent for purposes of Item 3 of Form N-CSR.

Item 4.

Principal Accountant Fees and Services

Fees and Services

The following table presents fees billed by Deloitte & Touche LLP, the member firms of Deloitte Touche Tohmatsu, and their respective affiliates (collectively, “Deloitte Entities”) in each of the last two fiscal years for services rendered to Fidelity SAI Long-Term Treasury Bond Index Fund and Fidelity SAI U.S. Treasury Bond Index Fund (the “Funds”):

Services Billed by Deloitte Entities

February 28, 2021 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity SAI Long-Term Treasury Bond Index Fund	$39,100	$-	$9,100	$900
Fidelity SAI U.S. Treasury Bond Index Fund	$43,800	$-	$7,200	$1,100

February 29, 2020 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity SAI Long-Term Treasury Bond Index Fund	$40,500	$100	$9,100	$1,000
Fidelity SAI U.S. Treasury Bond Index Fund	$45,300	$100	$7,200	$1,100

^AAmounts may reflect rounding.

The following table presents fees billed by PricewaterhouseCoopers LLP (“PwC”) in each of the last two fiscal years for services rendered to Fidelity Intermediate Treasury Bond Index Fund, Fidelity Long-Term Treasury Bond Index Fund, Fidelity Series Long-Term Treasury Bond Index Fund and Fidelity Short-Term Treasury Bond Index Fund (the “Funds”):

Services Billed by PwC

February 28, 2021 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity Intermediate Treasury Bond Index Fund	$38,300	$3,300	$8,700	$1,800
Fidelity Long-Term Treasury Bond Index Fund	$38,300	$3,300	$8,700	$1,800
Fidelity Series Long-Term Treasury Bond Index Fund	$44,300	$3,500	$7,700	$1,900
Fidelity Short-Term Treasury Bond Index Fund	$38,300	$3,300	$8,700	$1,800

February 29, 2020 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity Intermediate Treasury Bond Index Fund	$39,000	$3,800	$8,700	$2,100
Fidelity Long-Term Treasury Bond Index Fund	$39,000	$3,800	$8,700	$2,100
Fidelity Series Long-Term Treasury Bond Index Fund	$42,500	$3,900	$7,700	$2,200
Fidelity Short-Term Treasury Bond Index Fund	$39,000	$3,800	$8,700	$2,100

^AAmounts may reflect rounding

The following table(s) present(s) fees billed by Deloitte Entities and PwC that were required to be approved by the Audit Committee for services that relate directly to the operations and financial reporting of the Fund(s) and that are rendered on behalf of Fidelity Management & Research Company LLC ("FMR") and entities controlling, controlled by, or under common control with FMR (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) that provide ongoing services to the Fund(s) (“Fund Service Providers”):

Services Billed by Deloitte Entities


	February 28, 2021^A	February 29, 2020^A
Audit-Related Fees	$-	$287,500
Tax Fees	$-	$3,000
All Other Fees	$-	$-

^A Amounts may reflect rounding.

Services Billed by PwC


	February 28, 2021^A	February 29, 2020^A
Audit-Related Fees	$9,436,200	$7,927,700
Tax Fees	$14,300	$28,000
All Other Fees	$-	$-

^A Amounts may reflect rounding.

“Audit-Related Fees” represent fees billed for assurance and related services that are reasonably related to the performance of the fund audit or the review of the fund's financial statements and that are not reported under Audit Fees.

“Tax Fees” represent fees billed for tax compliance, tax advice or tax planning that relate directly to the operations and financial reporting of the fund.

“All Other Fees” represent fees billed for services provided to the fund or Fund Service Provider, a significant portion of which are assurance related, that relate directly to the operations and financial reporting of the fund, excluding those services that are reported under Audit Fees, Audit-Related Fees or Tax Fees.

Assurance services must be performed by an independent public accountant.

* * *

The aggregate non-audit fees billed by Deloitte Entities and PwC for services rendered to the Fund(s), FMR (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any Fund Service Provider for each of the last two fiscal years of the Fund(s) are as follows:


Billed By	February 28, 2021^A	February 29, 2020^A
Deloitte Entities	$576,800	$588,100
PwC	$14,579,900	$12,651,000

^A Amounts may reflect rounding.

The trust's Audit Committee has considered non-audit services that were not pre-approved that were provided by Deloitte Entities and PwC to Fund Service Providers to be compatible with maintaining the independence of Deloitte Entities and PwC in its(their) audit of the Fund(s), taking into account representations from Deloitte Entities and PwC, in accordance with Public Company Accounting Oversight Board rules, regarding its independence from the Fund(s) and its(their) related entities and FMR’s review of the appropriateness and permissibility under applicable law of such non-audit services prior to their provision to the Fund(s) Service Providers.

Audit Committee Pre-Approval Policies and Procedures

The trust’s Audit Committee must pre-approve all audit and non-audit services provided by a fund’s independent registered public accounting firm relating to the operations or financial reporting of the fund. Prior to the commencement of any audit or non-audit services to a fund, the Audit Committee reviews the services to determine whether they are appropriate and permissible under applicable law.

The Audit Committee has adopted policies and procedures to, among other purposes, provide a framework for the Committee’s consideration of non-audit services by the audit firms that audit the Fidelity funds. The policies and procedures require that any non-audit service provided by a fund audit firm to a Fidelity fund and any non-audit service provided by a fund auditor to a Fund Service Provider that relates directly to the operations and financial reporting of a Fidelity fund (“Covered Service”) are subject to approval by the Audit Committee before such service is provided.

All Covered Services must be approved in advance of provision of the service either: (i) by formal resolution of the Audit Committee, or (ii) by oral or written approval of the service by the Chair of the Audit Committee (or if the Chair is unavailable, such other member of the Audit Committee as may be designated by the Chair to act in the Chair’s absence). The approval contemplated by (ii) above is permitted where the Treasurer determines that action on such an engagement is necessary before the next meeting of the Audit Committee.

Non-audit services provided by a fund audit firm to a Fund Service Provider that do not relate directly to the operations and financial reporting of a Fidelity fund are reported to the Audit Committee periodically.

Non-Audit Services Approved Pursuant to Rule 2-01(c)(7)(i)(C) and (ii) of Regulation S-X (“De Minimis Exception”)

There were no non-audit services approved or required to be approved by the Audit Committee pursuant to the De Minimis Exception during the Fund’s(s’) last two fiscal years relating to services provided to (i) the Fund(s) or (ii) any Fund Service Provider that relate directly to the operations and financial reporting of the Fund(s).

Item 5.

Audit Committee of Listed Registrants

Not applicable.

Item 6.

Investments

(a)

Not applicable.

(b)

Not applicable.

Item 7.

Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

Not applicable.

Item 8.

Portfolio Managers of Closed-End Management Investment Companies

Not applicable.

Item 9.

Purchase of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

Not applicable.

Item 10.

Submission of Matters to a Vote of Security Holders

There were no material changes to the procedures by which shareholders may recommend nominees to the trust’s Board of Trustees.

Item 11.

Controls and Procedures

(a)(i) The President and Treasurer and the Chief Financial Officer have concluded that the trust’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act) provide reasonable assurances that material information relating to the trust is made known to them by the appropriate persons, based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this report.

(a)(ii) There was no change in the trust’s internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act) that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the trust’s internal control over financial reporting.

Item 12.

Disclosure of Securities Lending Activities for Closed-End Management

Investment Companies

Not applicable.

Item 13.

Exhibits


(a)	(1)	Code of Ethics pursuant to Item 2 of Form N-CSR is filed and attached hereto as EX-99.CODE ETH.
(a)	(2)	Certification pursuant to Rule 30a-2(a) under the Investment Company Act of 1940 (17 CFR 270.30a-2(a)) is filed and attached hereto as Exhibit 99.CERT.
(a)	(3)	Not applicable.
(b)		Certification pursuant to Rule 30a-2(b) under the Investment Company Act of 1940 (17 CFR 270.30a-2(b)) is furnished and attached hereto as Exhibit 99.906CERT.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Fidelity Salem Street Trust


By:	/s/Laura M. Del Prato
	Laura M. Del Prato
	President and Treasurer

Date:	April 21, 2021

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 the registrant and in the capacities and on the dates indicated.


By:	/s/Laura M. Del Prato
	Laura M. Del Prato
	President and Treasurer

Date:	April 21, 2021


By:	/s/John J. Burke III
	John J. Burke III
	Chief Financial Officer

Date:	April 21, 2021

Fidelity Real Estate Index Fund (FSRNX) N-CSRCertified annual shareholder report (management investment company)