Fidelity SAI Municipal Income NCSRS Certified semi-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, MA 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:	August 31, 2022

Item 1.

Reports to Stockholders

Fidelity® Series Long-Term Treasury Bond Index Fund

Semi-Annual Report

August 31, 2022

Contents

Investment Summary

Schedule of Investments

Financial Statements

Notes to Financial Statements

Shareholder Expense Example

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

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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.

Investment Summary August 31, 2022 (Unaudited)

Coupon Distribution (% of Fund's Investments)

1 - 1.99%	19.5
2 - 2.99%	48.7
3 - 3.99%	25.2
4 - 4.99%	4.4
5 - 5.99%	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)

Schedule of Investments August 31, 2022 (Unaudited)

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.2%
	Principal Amount (a)	Value ($)
U.S. Treasury Obligations - 99.2%
U.S. Treasury Bonds:
1.125% 5/15/40	398,337,000	271,118,121
1.125% 8/15/40	198,730,000	134,034,069
1.25% 5/15/50	125,768,000	77,764,909
1.375% 11/15/40	1,033,963,000	727,409,121
1.375% 8/15/50	284,828,000	182,134,153
1.625% 11/15/50	193,973,000	132,712,387
1.75% 8/15/41	476,080,000	353,712,563
1.875% 2/15/41	632,606,000	484,660,212
1.875% 2/15/51	656,425,000	478,959,477
1.875% 11/15/51	610,140,000	444,305,852
2% 11/15/41	808,880,000	628,335,460
2% 2/15/50	404,349,000	305,852,111
2% 8/15/51	856,520,000	643,460,650
2.25% 5/15/41	404,582,000	329,923,978
2.25% 8/15/46	72,841,000	57,020,845
2.25% 8/15/49	429,147,000	343,686,400
2.25% 2/15/52	1,323,220,000	1,056,921,975
2.375% 2/15/42	1,538,360,000	1,272,271,866
2.375% 11/15/49	502,572,000	414,170,369
2.375% 5/15/51	635,074,000	522,844,517
2.5% 2/15/45	390,549,000	322,843,668
2.5% 2/15/46	117,718,000	97,039,178
2.5% 5/15/46	136,970,000	112,866,491
2.75% 8/15/42	230,060,000	202,111,304
2.75% 11/15/42	113,934,000	99,883,624
2.75% 8/15/47	745,784,000	648,045,509
2.75% 11/15/47	327,877,000	285,406,682
2.875% 5/15/43	118,182,000	105,329,708
2.875% 8/15/45	36,332,000	32,124,017
2.875% 11/15/46	25,000	22,158
2.875% 5/15/49	638,599,000	580,775,853
2.875% 5/15/52	117,480,000	108,265,163
3% 5/15/42	100,699,000	92,536,874
3% 11/15/44	109,417,000	98,945,452
3% 5/15/45	135,524,000	122,448,051
3% 11/15/45	65,242,000	59,031,268
3% 2/15/47	512,294,000	464,666,667
3% 5/15/47	219,562,000	199,492,661
3% 2/15/48	676,869,000	619,943,261
3% 8/15/48	100,182,000	92,280,927
3% 2/15/49	637,787,000	592,942,602
3% 8/15/52	203,700,000	193,101,234
3.125% 11/15/41	59,163,000	55,698,729
3.125% 2/15/42	14,640,000	13,763,888
3.125% 2/15/43	114,181,000	106,125,887
3.125% 8/15/44	77,766,000	71,912,286
3.125% 5/15/48	348,642,000	328,063,950
3.25% 5/15/42	241,680,000	231,182,025
3.375% 8/15/42	164,400,000	160,418,438
3.375% 5/15/44	122,930,000	118,593,836
3.375% 11/15/48	13,091,000	12,965,715
3.5% 2/15/39	106,134,000	108,762,474
3.625% 8/15/43	125,692,000	126,300,821
3.625% 2/15/44	134,657,000	135,062,023
3.75% 8/15/41	90,738,000	93,644,452
3.75% 11/15/43	85,269,000	87,307,462
3.875% 8/15/40	46,505,000	49,224,452
4.25% 5/15/39	7,357,000	8,257,945
4.25% 11/15/40	61,567,000	68,399,494
4.375% 2/15/38	135,904,000	155,111,057
4.375% 11/15/39	17,280,000	19,645,200
4.375% 5/15/40	79,923,000	90,578,359
4.375% 5/15/41	80,788,000	91,019,042
4.5% 2/15/36	133,278,000	153,665,369
4.5% 5/15/38	33,092,000	38,245,821
4.5% 8/15/39	1,044,000	1,205,738
4.625% 2/15/40	35,743,000	41,868,177
4.75% 2/15/37	35,563,000	42,099,090
4.75% 2/15/41	19,013,000	22,501,440
5% 5/15/37	145,827,000	176,855,112
U.S. Treasury Notes 2.75% 8/15/32 (b)	19,400,000	18,714,938

TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS (Cost $20,195,833,902)		16,618,594,607

Money Market Funds - 1.2%
	Shares	Value ($)
Fidelity Cash Central Fund 2.33% (c)	189,682,574	189,720,511
Fidelity Securities Lending Cash Central Fund 2.34% (c)(d)	15,362,274	15,363,810
TOTAL MONEY MARKET FUNDS (Cost $205,084,321)		205,084,321

TOTAL INVESTMENT IN SECURITIES - 100.4% (Cost $20,400,918,223)	16,823,678,928
NET OTHER ASSETS (LIABILITIES) - (0.4)%	(74,440,328)
NET ASSETS - 100.0%	16,749,238,600

Legend

(a)	Amount is stated in United States dollars unless otherwise noted.

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

(c)

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 are available on the SEC's website or upon request.

(d)	Investment made with cash collateral received from securities on loan.

Affiliated Central Funds

Fiscal year to date information regarding the Fund's investments in Fidelity Central Funds, including the ownership percentage, is presented below.

Affiliate	Value, beginning of period ($)	Purchases ($)	Sales Proceeds ($)	Dividend Income ($)	Realized Gain (loss) ($)	Change in Unrealized appreciation (depreciation) ($)	Value, end of period ($)	%ownership, end of period
Fidelity Cash Central Fund 2.33%	125,270,842	528,595,025	464,145,356	392,049	-	-	189,720,511	0.4%
Fidelity Securities Lending Cash Central Fund 2.34%	133,000,000	4,550,800,893	4,668,437,083	383,164	-	-	15,363,810	0.0%
Total	258,270,842	5,079,395,918	5,132,582,439	775,213	-	-	205,084,321

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 August 31, 2022, 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	16,618,594,607	-	16,618,594,607	-

Money Market Funds	205,084,321	205,084,321	-	-
Total Investments in Securities:	16,823,678,928	205,084,321	16,618,594,607	-

Financial Statements

Statement of Assets and Liabilities
			August 31, 2022 (Unaudited)

Assets
Investment in securities, at value (including securities loaned of $15,014,633) - See accompanying schedule:	$16,618,594,607
Unaffiliated issuers (cost $20,195,833,902)	$16,618,594,607
Fidelity Central Funds (cost $205,084,321)	205,084,321

Total Investment in Securities (cost $20,400,918,223)		$	16,823,678,928
Receivable for investments sold			3,899,203
Receivable for fund shares sold			218,462,241
Interest receivable			70,681,780
Distributions receivable from Fidelity Central Funds			273,589
Total assets			17,116,995,741
Liabilities
Payable for investments purchased	$352,134,412
Payable for fund shares redeemed	222,731
Distributions payable	80
Other payables and accrued expenses	36,108
Collateral on securities loaned	15,363,810
Total Liabilities			367,757,141
Net Assets		$	16,749,238,600
Net Assets consist of:
Paid in capital		$	20,530,317,361
Total accumulated earnings (loss)			(3,781,078,761)
Net Assets		$	16,749,238,600
Net Asset Value , offering price and redemption price per share ($16,749,238,600 ÷ 2,578,493,432 shares)		$	6.50

Statement of Operations
			Six months ended August 31, 2022 (Unaudited)
Investment Income
Interest		$	214,866,645
Income from Fidelity Central Funds (including $383,164 from security lending)			775,213
Total Income			215,641,858
Expenses
Custodian fees and expenses	71,449
Independent trustees' fees and expenses	24,724
Total expenses before reductions	96,173
Expense reductions	(2)
Total expenses after reductions			96,171
Net Investment income (loss)			215,545,687
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment Securities:
Unaffiliated issuers	(195,040,233)
Total net realized gain (loss)			(195,040,233)
Change in net unrealized appreciation (depreciation) on investment securities			(3,301,792,229)
Net gain (loss)			(3,496,832,462)
Net increase (decrease) in net assets resulting from operations		$	(3,281,286,775)

Statement of Changes in Net Assets

		Six months ended August 31, 2022 (Unaudited)		Year ended February 28, 2022
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$	215,545,687	$	245,724,588
Net realized gain (loss)		(195,040,233)		12,567,404
Change in net unrealized appreciation (depreciation)		(3,301,792,229)		(430,136,750)
Net increase (decrease) in net assets resulting from operations		(3,281,286,775)		(171,844,758)
Distributions to shareholders		(205,930,889)		(285,111,393)
Share transactions
Proceeds from sales of shares		6,124,860,439		8,332,557,368
Reinvestment of distributions		205,930,889		285,074,438
Cost of shares redeemed		(1,223,353,245)		(2,388,088,438)
Net increase (decrease) in net assets resulting from share transactions		5,107,438,083		6,229,543,368
Total increase (decrease) in net assets		1,620,220,419		5,772,587,217

Net Assets
Beginning of period		15,129,018,181		9,356,430,964
End of period	$	16,749,238,600	$	15,129,018,181

Other Information
Shares
Sold		851,490,209		1,004,893,922
Issued in reinvestment of distributions		30,139,914		33,982,195
Redeemed		(181,545,947)		(283,430,527)
Net increase (decrease)		700,084,176		755,445,590

Fidelity® Series Long-Term Treasury Bond Index

		Six months ended (Unaudited) August 31, 2022		Years ended February 28, 2022		2021		2020 A		2019		2018
Selected Per-Share Data
Net asset value, beginning of period	$	8.05	$	8.33	$	10.06	$	8.43	$	8.36	$	8.59
Income from Investment Operations
Net investment income (loss) B,C		.091		.175		.201		.249		.248		.241
Net realized and unrealized gain (loss)		(1.554)		(.253)		(.752)		2.319		.069		(.244)
Total from investment operations		(1.463)		(.078)	��	(.551)		2.568		.317		(.003)
Distributions from net investment income		(.087)		(.169)		(.199)		(.243)		(.247)		(.227)
Distributions from net realized gain		-		(.033)		(.980)		(.695)		-		-
Total distributions		(.087)		(.202)		(1.179)		(.938)		(.247)		(.227)
Net asset value, end of period	$	6.50	$	8.05	$	8.33	$	10.06	$	8.43	$	8.36
Total Return D,E		(18.23)%		(1.01)%		(6.47)%		31.91%		3.84%		(.12)%
Ratios to Average Net Assets C,F,G
Expenses before reductions H		-% I		-%		-%		-%		-%		-%
Expenses net of fee waivers, if any H		-% I		-%		-%		-%		-%		-%
Expenses net of all reductions H		-% I		-%		-%		-%		-%		-%
Net investment income (loss)		2.61% I		2.10%		2.03%		2.68%		2.98%		2.76%
Supplemental Data
Net assets, end of period (000 omitted)	$	16,749,239	$	15,129,018	$	9,356,431	$	7,414,223	$	10,466,444	$	4,380,830
Portfolio turnover rate J		11% I		18%		56%		33% K		23%		15%

A For the year ended February 29.

B Calculated based on average shares outstanding during the period.

C Net investment income (loss) is affected by the timing of the declaration of dividends by any underlying mutual funds or exchange-traded funds (ETFs). Net investment income (loss) of any such underlying funds is not included in the Fund's net investment income (loss) ratio.

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 adviser, 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.

Notes to Financial Statements (Unaudited)

For the period ended August 31, 2022

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, Fidelity managed 529 plans, and Fidelity managed collective investment trusts. 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.

Funds may 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 Schedule of Investments lists any Fidelity Central Funds held as an investment as of period end, but does not include the underlying holdings of each Fidelity Central Fund. An investing fund indirectly bears its proportionate share of the expenses of the underlying Fidelity Central Funds.

Based on its investment objective, each Fidelity Central Fund may invest or participate in various investment vehicles or strategies that are similar to those of the investing fund. These strategies are consistent with the investment objectives of the investing fund and may involve certain economic risks which may cause a decline in value of each of the Fidelity Central Funds and thus a decline in the value of the investing fund.

Fidelity Central Fund	Investment Manager	Investment Objective	Investment Practices	Expense Ratio A
Fidelity Money Market Central Funds	Fidelity Management & Research Company LLC (FMR)	Each fund seeks to obtain a high level of current income consistent with the preservation of capital and liquidity.	Short-term Investments	Less than .005%

A Expenses expressed as a percentage of average net assets and are as of each underlying Central Fund's most recent annual or semi-annual shareholder report.

A complete unaudited list of holdings for each Fidelity Central Fund is available upon request or at the Securities and Exchange Commission website at www.sec.gov. In addition, the financial statements of the Fidelity Central Funds which contain the significant accounting policies (including investment valuation policies) of those funds, and are not covered by the Report of Independent Registered Public Accounting Firm, are available on the Securities and Exchange Commission 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 Fund's Schedule of Investments lists any underlying mutual funds or exchange-traded funds (ETFs) but does not include the underlying holdings of these funds. 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 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 - unadjusted 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.

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 August 31, 2022 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. Expenses included in the accompanying financial statements reflect the expenses of that fund and do not include any expenses associated with any underlying mutual funds or exchange-traded funds. Although not included in a fund's expenses, a fund indirectly bears its proportionate share of these expenses through the net asset value of each underlying mutual fund or exchange-traded fund. 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. 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.

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 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:

Gross unrealized appreciation	$ 455,113
Gross unrealized depreciation	(3,566,145,317)
Net unrealized appreciation (depreciation)	$(3,565,690,204)
Tax cost	$20,389,369,132

The Fund elected to defer to its next fiscal year approximately $9,524,226 of capital losses recognized during the period November 1, 2021 to February 28, 2022.

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.

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. Any interfund trades are included within the respective purchases and sales amounts shown in the Purchases and Sales of Investments note. During the period, there were no interfund trades.

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 commitment fees on the pro-rata portion of the line of credit are borne by the investment adviser. 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 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	$ 41,103	$ -	$-

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 $2.

8. Other.

A 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, a fund may also enter into contracts that provide general indemnifications. A fund's maximum exposure under these arrangements is unknown as this would be dependent on future claims that may be made against a fund. The risk of material loss from such claims is considered remote.

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. Risk and Uncertainties.

Many factors affect a fund's performance. Developments that disrupt global economies and financial markets, such as pandemics, epidemics, outbreaks of infectious diseases, war, terrorism, and environmental disasters, may significantly affect a fund's investment performance. The effects of these developments to a fund will be impacted by the types of securities in which a fund invests, the financial condition, industry, economic sector, and geographic location of an issuer, and a fund's level of investment in the securities of that issuer.

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 (March 1, 2022 to August 31, 2022).

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. In addition, if these transactional costs were included, your costs would have been higher.

	Annualized Expense Ratio- A	Beginning Account Value March 1, 2022	Ending Account Value August 31, 2022	Expenses Paid During Period- C March 1, 2022 to August 31, 2022

Fidelity® Series Long-Term Treasury Bond Index Fund	-%- D
Actual		$ 1,000	$ 817.70	$- E
Hypothetical- B		$ 1,000	$ 1,025.21	$- E

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

B 5% return per year before expenses

C Expenses are equal to the annualized expense ratio, multiplied by the average account value over the period, multiplied by 184/ 365 (to reflect the one-half year period). The fees and expenses of any Underlying Funds are not included in each annualized expense ratio.

D Amount represents less than .005%.

E Amount represents less than $.005.

1.9872675.106

XS8-SANN-1022

Fidelity® SAI U.S. Treasury Bond Index Fund

Semi-Annual Report

August 31, 2022

Offered exclusively to certain clients of the Adviser, or its affiliates, including Strategic Advisers LLC (Strategic Advisers) - 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.

Contents

Investment Summary

Schedule of Investments

Financial Statements

Notes to Financial Statements

Shareholder Expense Example

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.

Investment Summary August 31, 2022 (Unaudited)

Coupon Distribution (% of Fund's Investments)

0.01 - 0.99%	25.7
1 - 1.99%	28.2
2 - 2.99%	30.2
3 - 3.99%	8.1
4 - 4.99%	1.0
5 - 5.99%	1.1
6 - 6.99%	3.8
7 - 7.99%	0.4
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)

Schedule of Investments August 31, 2022 (Unaudited)

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.4%
	Principal Amount (a)	Value ($)
U.S. Treasury Obligations - 99.4%
U.S. Treasury Bonds:
1.125% 5/15/40	72,984,000	49,674,735
1.125% 8/15/40	146,737,000	98,967,227
1.25% 5/15/50	28,872,000	17,852,144
1.375% 11/15/40	173,534,300	122,084,091
1.375% 8/15/50	46,570,000	29,779,332
1.625% 11/15/50	18,637,500	12,751,399
1.75% 8/15/41	195,327,000	145,121,857
1.875% 2/15/41	14,329,000	10,977,917
1.875% 2/15/51	108,131,000	78,897,615
1.875% 11/15/51	84,163,000	61,287,759
2% 11/15/41	101,600,000	78,922,563
2% 2/15/50	73,378,000	55,503,578
2% 8/15/51	108,945,000	81,844,931
2.25% 5/15/41	83,633,000	68,200,098
2.25% 8/15/46	1,800,000	1,409,063
2.25% 8/15/49	71,080,000	56,925,085
2.25% 2/15/52	133,800,000	106,872,750
2.375% 2/15/42	191,400,000	158,293,791
2.375% 11/15/49	179,560,000	147,975,676
2.375% 5/15/51	163,237,000	134,389,961
2.5% 2/15/45	1,000	827
2.5% 2/15/46	26,923,000	22,193,597
2.5% 5/15/46	21,383,000	17,620,093
2.75% 8/15/42	70,438,000	61,880,883
2.75% 11/15/42	29,826,000	26,147,848
2.75% 8/15/47	57,931,000	50,338,871
2.75% 11/15/47	23,318,000	20,297,590
2.875% 5/15/43	21,584,000	19,236,740
2.875% 8/15/45	64,054,000	56,635,246
2.875% 11/15/46	12,089,000	10,714,821
2.875% 5/15/49	11,811,000	10,741,551
2.875% 5/15/52	123,000,000	113,352,188
3% 5/15/42	31,038,000	28,522,225
3% 11/15/44	4,000,000	3,617,188
3% 5/15/45	7,200,000	6,505,312
3% 11/15/45	10,200,000	9,229,008
3% 2/15/47	77,389,000	70,194,241
3% 5/15/47	84,592,000	76,859,763
3% 2/15/48	46,259,000	42,368,546
3% 8/15/48	51,808,000	47,722,049
3% 2/15/49	120,511,000	112,037,570
3% 8/15/52	18,100,000	17,158,234
3.125% 8/15/25	18,000,000	17,818,594
3.125% 11/15/41	58,864,000	55,417,237
3.125% 2/15/43	1,000	929
3.125% 5/15/48	96,704,500	90,996,668
3.25% 5/15/42	64,100,000	61,315,656
3.375% 8/15/42	9,500,000	9,269,922
3.375% 5/15/44	4,900,000	4,727,160
3.375% 11/15/48	187,391,300	185,597,907
3.5% 2/15/39	315,000	322,801
3.625% 8/15/43	15,601,000	15,676,567
3.625% 2/15/44	26,356,000	26,435,274
3.75% 8/15/41	12,045,000	12,430,816
3.75% 11/15/43	12,484,000	12,782,446
3.875% 8/15/40	10,674,000	11,298,179
4.25% 5/15/39	7,898,000	8,865,197
4.25% 11/15/40	13,880,000	15,420,355
4.375% 2/15/38	17,484,000	19,954,981
4.375% 11/15/39	4,140,000	4,706,663
4.375% 5/15/41	817,000	920,465
4.5% 2/15/36	26,832,200	30,936,688
4.5% 8/15/39	3,831,000	4,424,506
4.625% 2/15/40	4,405,000	5,159,872
4.75% 2/15/37	13,000	15,389
4.75% 2/15/41	54,900,000	64,972,863
5% 5/15/37	5,067,000	6,145,123
5.25% 11/15/28	31,601,000	34,910,464
5.25% 2/15/29	774,000	859,533
5.375% 2/15/31	51,362,000	59,487,629
5.5% 8/15/28	66,565,000	74,131,569
6% 2/15/26	3,771,000	4,075,184
6.125% 11/15/27	143,904,000	162,470,989
6.125% 8/15/29	12,944,000	15,216,784
6.25% 8/15/23	67,375,000	69,185,703
6.25% 5/15/30	12,278,000	14,778,204
6.375% 8/15/27	49,000,000	55,599,688
6.5% 11/15/26	121,539,000	136,080,952
6.625% 2/15/27	24,450,000	27,647,602
6.75% 8/15/26	23,000	25,831
6.875% 8/15/25	107,691,000	117,715,518
7.5% 11/15/24	30,367,000	32,938,705
7.625% 11/15/22	50,000	50,489
7.625% 2/15/25	20,938,000	22,953,283
U.S. Treasury Notes:
0.125% 8/15/23	1,745,000	1,690,264
0.125% 9/15/23	44,956,000	43,431,711
0.125% 10/15/23	6,857,000	6,605,487
0.125% 12/15/23	121,834,200	116,760,948
0.125% 1/15/24	127,763,000	122,043,610
0.125% 2/15/24	52,741,000	50,248,164
0.25% 11/15/23	179,672,000	172,948,336
0.25% 3/15/24	61,537,000	58,570,725
0.25% 5/15/24	115,780,000	109,638,232
0.25% 5/31/25	68,744,000	62,935,669
0.25% 6/30/25	90,476,400	82,669,276
0.25% 7/31/25	76,826,000	69,971,680
0.25% 8/31/25	47,244,000	42,897,921
0.25% 9/30/25	81,580,000	73,925,502
0.25% 10/31/25	52,921,300	47,815,221
0.375% 10/31/23	43,600,000	42,077,406
0.375% 4/15/24	75,049,000	71,372,771
0.375% 7/15/24	119,138,000	112,529,564
0.375% 8/15/24	183,032,000	172,400,414
0.375% 9/15/24	94,577,000	88,843,269
0.375% 4/30/25	11,267,000	10,379,284
0.375% 11/30/25	21,000,000	18,998,438
0.375% 12/31/25	58,183,100	52,517,066
0.375% 1/31/26	13,705,000	12,337,177
0.375% 7/31/27	106,214,000	92,095,006
0.375% 9/30/27	68,726,000	59,238,590
0.5% 11/30/23	157,300,000	151,634,743
0.5% 3/31/25	62,681,000	58,095,004
0.5% 2/28/26	130,411,000	117,665,362
0.5% 4/30/27	53,944,000	47,308,467
0.5% 5/31/27	25,220,000	22,072,426
0.5% 6/30/27	23,781,000	20,768,430
0.5% 8/31/27	76,109,000	66,205,911
0.625% 10/15/24	114,674,000	108,035,451
0.625% 7/31/26	129,205,000	115,931,204
0.625% 3/31/27	17,704,000	15,656,283
0.625% 11/30/27	30,400,700	26,429,609
0.625% 12/31/27	161,839,900	140,351,860
0.625% 5/15/30	194,827,000	160,595,288
0.625% 8/15/30	137,994,900	113,204,331
0.75% 12/31/23	184,300,000	177,791,906
0.75% 3/31/26	157,216,000	142,851,616
0.75% 4/30/26	54,688,000	49,605,861
0.75% 5/31/26	144,299,000	130,618,778
0.75% 8/31/26	75,299,000	67,774,982
0.75% 1/31/28	154,028,000	134,239,012
0.875% 1/31/24	136,800,000	131,857,032
0.875% 6/30/26	55,301,000	50,211,580
0.875% 9/30/26	93,577,000	84,537,316
0.875% 11/15/30	137,380,900	114,836,480
1% 12/15/24	168,400,000	159,269,563
1% 7/31/28	75,309,000	65,833,598
1.125% 1/15/25	38,000,000	35,966,406
1.125% 2/28/25	143,825,900	135,775,021
1.125% 10/31/26	114,815,000	104,616,199
1.125% 2/28/27	3,938,000	3,572,351
1.125% 2/29/28	50,970,000	45,289,633
1.125% 8/31/28	209,607,000	184,347,719
1.125% 2/15/31	109,498,000	93,103,241
1.25% 7/31/23	5,561,000	5,450,432
1.25% 8/31/24 (b)	46,824,000	44,843,125
1.25% 11/30/26	81,129,000	74,233,035
1.25% 12/31/26	60,300,000	55,101,480
1.25% 3/31/28	132,308,000	118,095,226
1.25% 4/30/28	71,799,000	63,999,273
1.25% 5/31/28	196,074,000	174,597,770
1.25% 6/30/28	95,235,000	84,625,226
1.25% 9/30/28	35,238,000	31,167,736
1.25% 8/15/31	182,666,000	155,473,026
1.375% 8/31/23	1,103,000	1,080,164
1.375% 9/30/23	6,179,000	6,041,421
1.375% 12/31/28	26,100,000	23,214,726
1.375% 11/15/31	96,246,000	82,444,474
1.5% 2/29/24	82,300,000	79,940,304
1.5% 9/30/24	26,223,000	25,196,616
1.5% 10/31/24	2,615,000	2,508,766
1.5% 8/15/26	33,170,000	30,791,089
1.5% 1/31/27	69,100,000	63,760,946
1.5% 11/30/28	78,300,000	70,154,965
1.5% 2/15/30	49,893,000	44,256,650
1.625% 10/31/23	5,035,000	4,930,366
1.625% 2/15/26	29,244,000	27,467,655
1.625% 5/15/26	35,738,000	33,475,059
1.625% 10/31/26	105,277,000	97,989,858
1.625% 11/30/26	9,625,000	8,956,138
1.625% 8/15/29	211,462,000	190,266,238
1.625% 5/15/31	231,893,000	204,853,914
1.75% 6/30/24	115,065,800	111,568,879
1.75% 7/31/24	84,636,000	81,974,595
1.75% 12/31/24	262,983,000	252,925,953
1.75% 3/15/25	95,900,000	91,861,709
1.75% 12/31/26	9,596,000	8,968,137
1.75% 1/31/29	76,900,000	69,918,922
1.75% 11/15/29	41,007,000	37,225,065
1.875% 8/31/24	1,000	970
1.875% 6/30/26	46,405,000	43,836,411
1.875% 7/31/26	63,142,000	59,568,064
1.875% 2/28/27	193,900,000	181,803,973
1.875% 2/28/29	51,800,000	47,479,961
1.875% 2/15/32	205,900,000	183,910,518
2% 4/30/24	2,462,000	2,404,008
2% 5/31/24	43,408,000	42,334,669
2% 6/30/24	97,375,000	94,864,551
2% 2/15/25	6,597,000	6,368,167
2% 8/15/25	34,227,000	32,795,081
2% 11/15/26	124,450,000	117,498,300
2.125% 11/30/23	2,629,000	2,586,587
2.125% 2/29/24	3,213,000	3,150,121
2.125% 7/31/24	12,095,000	11,798,295
2.125% 9/30/24	30,004,000	29,210,535
2.125% 11/30/24	147,546,000	143,229,127
2.125% 5/31/26	2,400,000	2,289,000
2.25% 12/31/23	35,029,000	34,467,989
2.25% 1/31/24	7,160,000	7,038,336
2.25% 4/30/24	1,000	980
2.25% 10/31/24	27,138,000	26,453,189
2.25% 11/15/24	49,622,000	48,348,498
2.25% 12/31/24	6,055,000	5,888,251
2.25% 11/15/25	106,223,000	102,206,443
2.25% 3/31/26	13,873,000	13,312,661
2.25% 2/15/27	44,880,000	42,735,928
2.25% 8/15/27	28,284,000	26,858,752
2.25% 11/15/27	6,200,000	5,873,531
2.375% 2/29/24	31,698,000	31,187,860
2.375% 8/15/24	35,598,000	34,866,572
2.375% 4/30/26	44,609,000	42,998,894
2.375% 5/15/27	7,901,000	7,555,023
2.375% 3/31/29	10,000,000	9,429,297
2.375% 5/15/29	124,499,000	117,403,529
2.5% 8/15/23	17,536,000	17,371,600
2.5% 1/31/24	207,306,000	204,471,737
2.5% 4/30/24	69,400,000	68,299,359
2.5% 5/15/24	68,026,000	66,939,179
2.5% 5/31/24	25,000,000	24,586,914
2.5% 1/31/25	5,697,000	5,567,260
2.5% 2/28/26	2,000	1,936
2.5% 3/31/27	95,900,000	92,341,210
2.625% 2/28/23	4,000	3,988
2.625% 3/31/25	16,295,000	15,950,641
2.625% 4/15/25	179,400,000	175,503,656
2.625% 1/31/26	1,204,000	1,171,078
2.625% 5/31/27	137,800,000	133,461,452
2.625% 2/15/29	128,344,000	123,089,918
2.75% 11/15/23	22,659,000	22,465,159
2.75% 2/15/24	9,154,000	9,059,242
2.75% 2/28/25	46,680,000	45,850,336
2.75% 5/15/25	11,800,000	11,572,758
2.75% 6/30/25 (b)	182,760,000	179,154,774
2.75% 8/31/25	28,037,000	27,444,499
2.75% 4/30/27	152,400,000	148,334,015
2.75% 2/15/28	86,418,200	83,717,631
2.75% 5/31/29	54,500,000	52,588,242
2.75% 8/15/32 (b)	28,700,000	27,686,531
2.875% 9/30/23 (b)	42,000,000	41,740,781
2.875% 10/31/23	174,771,000	173,624,065
2.875% 11/30/23	29,487,000	29,273,910
2.875% 4/30/25	80,986,000	79,685,795
2.875% 5/31/25	5,889,000	5,792,154
2.875% 6/15/25	84,100,000	82,707,094
2.875% 7/31/25	105,997,000	104,204,160
2.875% 5/15/28	73,985,000	72,077,574
2.875% 8/15/28	66,476,000	64,712,828
2.875% 4/30/29	52,700,000	51,246,633
2.875% 5/15/32	163,400,000	159,263,938
3% 6/30/24	76,400,000	75,737,468
3% 7/15/25	28,400,000	28,020,594
3% 9/30/25	98,160,000	96,760,453
3% 10/31/25	11,284,000	11,119,589
3.125% 8/31/27	9,600,000	9,514,500
3.125% 11/15/28	55,303,000	54,600,911
3.25% 6/30/27	9,800,000	9,753,297
3.25% 6/30/29	69,300,000	69,018,469

TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS (Cost $16,684,234,813)		15,482,441,079

Money Market Funds - 1.5%
	Shares	Value ($)
Fidelity Cash Central Fund 2.33% (c)	100,033,142	100,053,148
Fidelity Securities Lending Cash Central Fund 2.34% (c)(d)	128,382,118	128,394,956
TOTAL MONEY MARKET FUNDS (Cost $228,448,104)		228,448,104

TOTAL INVESTMENT IN SECURITIES - 100.9% (Cost $16,912,682,917)	15,710,889,183
NET OTHER ASSETS (LIABILITIES) - (0.9)%	(144,600,365)
NET ASSETS - 100.0%	15,566,288,818

Legend

(a)	Amount is stated in United States dollars unless otherwise noted.

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

(c)

(d)	Investment made with cash collateral received from securities on loan.

Affiliated Central Funds

Fiscal year to date information regarding the Fund's investments in Fidelity Central Funds, including the ownership percentage, is presented below.

Affiliate	Value, beginning of period ($)	Purchases ($)	Sales Proceeds ($)	Dividend Income ($)	Realized Gain (loss) ($)	Change in Unrealized appreciation (depreciation) ($)	Value, end of period ($)	%ownership, end of period
Fidelity Cash Central Fund 2.33%	35,697,335	1,214,284,270	1,149,928,457	340,049	-	-	100,053,148	0.2%
Fidelity Securities Lending Cash Central Fund 2.34%	665,434,093	1,853,348,135	2,390,387,272	215,724	-	-	128,394,956	0.4%
Total	701,131,428	3,067,632,405	3,540,315,729	555,773	-	-	228,448,104

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	15,482,441,079	-	15,482,441,079	-

Money Market Funds	228,448,104	228,448,104	-	-
Total Investments in Securities:	15,710,889,183	228,448,104	15,482,441,079	-

Financial Statements

Statement of Assets and Liabilities
			August 31, 2022 (Unaudited)

Assets
Investment in securities, at value (including securities loaned of $125,221,452) - See accompanying schedule:	$15,482,441,079
Unaffiliated issuers (cost $16,684,234,813)	$15,482,441,079
Fidelity Central Funds (cost $228,448,104)	228,448,104

Total Investment in Securities (cost $16,912,682,917)		$	15,710,889,183
Receivable for investments sold			133,871,241
Receivable for fund shares sold			16,104,559
Interest receivable			60,432,962
Distributions receivable from Fidelity Central Funds			145,994
Prepaid expenses			27,092
Receivable from investment adviser for expense reductions			215,030
Total assets			15,921,686,061
Liabilities
Payable for investments purchased	$211,102,359
Payable for fund shares redeemed	11,475,510
Distributions payable	3,376,162
Accrued management fee	521,516
Other payables and accrued expenses	526,740
Collateral on securities loaned	128,394,956
Total Liabilities			355,397,243
Net Assets		$	15,566,288,818
Net Assets consist of:
Paid in capital		$	16,916,636,367
Total accumulated earnings (loss)			(1,350,347,549)
Net Assets		$	15,566,288,818
Net Asset Value , offering price and redemption price per share ($15,566,288,818 ÷ 1,735,015,748 shares)		$	8.97

Statement of Operations
				Six months ended August 31, 2022 (Unaudited)
Investment Income
Interest			$	118,066,662
Income from Fidelity Central Funds (including $215,724 from security lending)				555,773
Total Income				118,622,435
Expenses
Management fee	$	2,594,205
Custodian fees and expenses		54,195
Independent trustees' fees and expenses		19,097
Registration fees		984,919
Audit		28,294
Legal		3,222
Miscellaneous		27,608
Total expenses before reductions		3,711,540
Expense reductions		(1,729,284)
Total expenses after reductions				1,982,256
Net Investment income (loss)				116,640,179
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment Securities:
Unaffiliated issuers		(78,289,910)
Total net realized gain (loss)				(78,289,910)
Change in net unrealized appreciation (depreciation) on investment securities				(910,098,153)
Net gain (loss)				(988,388,063)
Net increase (decrease) in net assets resulting from operations			$	(871,747,884)

Statement of Changes in Net Assets

		Six months ended August 31, 2022 (Unaudited)		Year ended February 28, 2022
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$	116,640,179	$	122,231,822
Net realized gain (loss)		(78,289,910)		(108,943,126)
Change in net unrealized appreciation (depreciation)		(910,098,153)		(275,137,045)
Net increase (decrease) in net assets resulting from operations		(871,747,884)		(261,848,349)
Distributions to shareholders		(94,263,876)		(115,889,986)
Share transactions
Proceeds from sales of shares		8,770,441,168		7,463,193,121
Reinvestment of distributions		84,363,660		115,399,217
Cost of shares redeemed		(3,549,858,117)		(5,548,868,507)
Net increase (decrease) in net assets resulting from share transactions		5,304,946,711		2,029,723,831
Total increase (decrease) in net assets		4,338,934,951		1,651,985,496

Net Assets
Beginning of period		11,227,353,867		9,575,368,371
End of period	$	15,566,288,818	$	11,227,353,867

Other Information
Shares
Sold		957,919,773		743,958,224
Issued in reinvestment of distributions		9,215,147		11,501,245
Redeemed		(378,943,790)		(556,662,183)
Net increase (decrease)		588,191,130		198,797,286

Fidelity® SAI US. Treasury Bond Index Fund

		Six months ended (Unaudited) August 31, 2022		Years ended February 28, 2022		2021		2020 A		2019		2018
Selected Per-Share Data
Net asset value, beginning of period	$	9.79	$	10.10	$	10.60	$	9.65	$	9.55	$	9.77
Income from Investment Operations
Net investment income (loss) B,C		.082		.106		.168		.229		.233		.192
Net realized and unrealized gain (loss)		(.837)		(.316)		(.191)		.937		.072		(.247)
Total from investment operations		(.755)		(.210)		(.023)		1.166		.305		(.055)
Distributions from net investment income		(.065)		(.098)		(.175)		(.216)		(.205)		(.165)
Distributions from net realized gain		-		(.002)		(.302)		-		-		-
Total distributions		(.065)		(.100)		(.477)		(.216)		(.205)		(.165)
Net asset value, end of period	$	8.97	$	9.79	$	10.10	$	10.60	$	9.65	$	9.55
Total Return D,E		(7.72)%		(2.09)%		(.33)%		12.21%		3.23%		(.59)%
Ratios to Average Net Assets C,F,G
Expenses before reductions		.06% H		.05%		.05%		.08%		.15%		.16%
Expenses net of fee waivers, if any		.03% H		.03%		.03%		.03%		.03%		.04%
Expenses net of all reductions		.03% H		.03%		.03%		.03%		.03%		.04%
Net investment income (loss)		1.78% H		1.06%		1.56%		2.27%		2.45%		1.95%
Supplemental Data
Net assets, end of period (000 omitted)	$	15,566,289	$	11,227,354	$	9,575,368	$	9,284,624	$	2,897,538	$	1,081,044
Portfolio turnover rate I		45% H		45%		167%		23%		73%		144%

A For the year ended February 29.

B 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).

Notes to Financial Statements (Unaudited)

For the period ended August 31, 2022

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.

Fidelity Central Fund	Investment Manager	Investment Objective	Investment Practices	Expense Ratio A
Fidelity Money Market Central Funds	Fidelity Management & Research Company LLC (FMR)	Each fund seeks to obtain a high level of current income consistent with the preservation of capital and liquidity.	Short-term Investments	Less than .005%

A Expenses expressed as a percentage of average net assets and are as of each underlying Central Fund's most recent annual or semi-annual shareholder report.

3. Significant Accounting Policies.

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 - unadjusted 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 August 31, 2022, is included at the end of the Fund's Schedule of Investments.

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	$ 3,292,510
Gross unrealized depreciation	(1,185,376,842)
Net unrealized appreciation (depreciation)	$(1,182,084,332)
Tax cost	$16,892,973,515

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 prior fiscal period end and is subject to adjustment.

Short-term	$(75,299,262)
Long-term	(28,551,095)
Total capital loss carryforward	$(103,850,357)

4. Fees and Other Transactions with Affiliates.

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

	Amount
Fidelity SAI U.S. Treasury Bond Index Fund	$ 10,271

6. Security Lending.

	Total Security Lending 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	$ 22,662	$ -	$-

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, 2023. 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 $1,729,267.

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 $17.

8. Other.

In addition, at the end of the period, the following mutual funds managed by the investment adviser or its affiliates were the owners of record of 10% or more of the total outstanding shares.

	Strategic Advisers Fidelity Core Income Fund
Fidelity SAI U.S. Treasury Bond Index Fund	26%

Mutual funds managed by the investment adviser or its affiliates, in aggregate, were the owners of record of more than 20% of the total outstanding shares.

Fund	% of shares held
Fidelity SAI U.S. Treasury Bond Index Fund	36%

9. Risk and Uncertainties.

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 (March 1, 2022 to August 31, 2022).

Actual Expenses

Hypothetical Example for Comparison Purposes

	Annualized Expense Ratio- A	Beginning Account Value March 1, 2022	Ending Account Value August 31, 2022	Expenses Paid During Period- C March 1, 2022 to August 31, 2022

Fidelity® SAI U.S. Treasury Bond Index Fund	.03%
Actual		$ 1,000	$ 922.80	$ .15
Hypothetical- B		$ 1,000	$ 1,025.05	$ .15

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

B 5% return per year before expenses

1.9872607.106

UYB-SANN-1022

Fidelity® SAI Long-Term Treasury Bond Index Fund

Semi-Annual Report

August 31, 2022

Contents

Investment Summary

Schedule of Investments

Financial Statements

Notes to Financial Statements

Shareholder Expense Example

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.

Investment Summary August 31, 2022 (Unaudited)

Coupon Distribution (% of Fund's Investments)

1 - 1.99%	14.5
2 - 2.99%	54.9
3 - 3.99%	29.8
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)

Schedule of Investments August 31, 2022 (Unaudited)

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 99.3%
	Principal Amount (a)	Value ($)
U.S. Treasury Obligations - 99.3%
U.S. Treasury Bonds:
1.25% 5/15/50	224,853,000	139,031,177
1.375% 8/15/50	441,948,000	282,605,027
1.625% 11/15/50	150,542,000	102,997,779
1.875% 2/15/51	287,213,000	209,564,517
1.875% 11/15/51	150,800,000	109,813,031
2% 2/15/50	85,743,800	64,857,146
2% 8/15/51	1,068,288,000	802,551,358
2.25% 8/15/46	155,154,000	121,456,491
2.25% 8/15/49	128,313,000	102,760,670
2.25% 2/15/52	216,600,000	173,009,250
2.375% 11/15/49	12,625,000	10,404,282
2.375% 5/15/51	165,670,000	136,393,005
2.5% 2/15/45	81,579,700	67,437,094
2.5% 2/15/46	103,885,000	85,636,139
2.5% 5/15/46	169,400,000	139,589,571
2.75% 8/15/42	112,603,500	98,923,934
2.75% 11/15/42	152,719,100	133,885,733
2.75% 8/15/47	220,457,000	191,565,076
2.75% 11/15/47	77,254,000	67,247,193
2.875% 5/15/43	87,520,200	78,002,378
2.875% 8/15/45	163,159,100	144,261,962
2.875% 11/15/46	304,196,000	269,617,469
2.875% 5/15/49	121,018,000	110,060,198
2.875% 5/15/52	440,800,000	406,224,750
3% 5/15/42	13,470,700	12,378,837
3% 11/15/44	800	723
3% 5/15/45	157,846,800	142,617,049
3% 11/15/45	103,206,000	93,381,273
3% 2/15/47	395,746,000	358,953,989
3% 5/15/47	290,348,000	263,808,378
3% 2/15/48	26,187,000	23,984,632
3% 8/15/48	75,355,000	69,411,963
3% 2/15/49	235,859,000	219,275,164
3% 8/15/52	20,000,000	18,959,375
3.125% 2/15/42	9,168,100	8,619,447
3.125% 2/15/43	54,354,600	50,520,053
3.125% 8/15/44	84,564,300	78,198,854
3.125% 5/15/48	205,894,000	193,741,428
3.25% 5/15/42	100,200,000	95,847,563
3.375% 5/15/44	17,923,800	17,291,566
3.375% 11/15/48	31,147,000	30,848,914
3.625% 8/15/43	297,600	299,042
3.625% 2/15/44	88,500	88,766
3.75% 11/15/43	60,982,100	62,439,953
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS (Cost $7,055,501,451)		5,788,562,199

Money Market Funds - 0.8%
	Shares	Value ($)
Fidelity Cash Central Fund 2.33% (b) (Cost $49,611,347)	49,601,427	49,611,347

TOTAL INVESTMENT IN SECURITIES - 100.1% (Cost $7,105,112,798)	5,838,173,546
NET OTHER ASSETS (LIABILITIES) - (0.1)%	(7,613,325)
NET ASSETS - 100.0%	5,830,560,221

Legend

(a)	Amount is stated in United States dollars unless otherwise noted.

(b)

Affiliated Central Funds

Fiscal year to date information regarding the Fund's investments in Fidelity Central Funds, including the ownership percentage, is presented below.

Affiliate	Value, beginning of period ($)	Purchases ($)	Sales Proceeds ($)	Dividend Income ($)	Realized Gain (loss) ($)	Change in Unrealized appreciation (depreciation) ($)	Value, end of period ($)	%ownership, end of period
Fidelity Cash Central Fund 2.33%	43,056,139	231,357,255	224,802,047	101,231	-	-	49,611,347	0.1%
Fidelity Securities Lending Cash Central Fund 2.34%	-	1,095,183,016	1,095,183,016	101,698	-	-	-	0.0%
Total	43,056,139	1,326,540,271	1,319,985,063	202,929	-	-	49,611,347

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	5,788,562,199	-	5,788,562,199	-

Money Market Funds	49,611,347	49,611,347	-	-
Total Investments in Securities:	5,838,173,546	49,611,347	5,788,562,199	-

Financial Statements

Statement of Assets and Liabilities
			August 31, 2022 (Unaudited)

Assets
Investment in securities, at value - See accompanying schedule:	$5,788,562,199
Unaffiliated issuers (cost $7,055,501,451)	$5,788,562,199
Fidelity Central Funds (cost $49,611,347)	49,611,347

Total Investment in Securities (cost $7,105,112,798)		$	5,838,173,546
Receivable for investments sold			60,714,434
Receivable for fund shares sold			1,735,239
Interest receivable			28,213,950
Distributions receivable from Fidelity Central Funds			69,148
Prepaid expenses			9,121
Receivable from investment adviser for expense reductions			74,744
Total assets			5,928,990,182
Liabilities
Payable for investments purchased	$96,613,236
Payable for fund shares redeemed	1,550,688
Distributions payable	22,046
Accrued management fee	193,944
Other payables and accrued expenses	50,047
Total Liabilities			98,429,961
Net Assets		$	5,830,560,221
Net Assets consist of:
Paid in capital		$	7,588,772,310
Total accumulated earnings (loss)			(1,758,212,089)
Net Assets		$	5,830,560,221
Net Asset Value , offering price and redemption price per share ($5,830,560,221 ÷ 683,246,288 shares)		$	8.53

Statement of Operations
				Six months ended August 31, 2022 (Unaudited)
Investment Income
Interest			$	74,363,117
Income from Fidelity Central Funds (including $101,698 from security lending)				202,929
Total Income				74,566,046
Expenses
Management fee	$	1,150,262
Custodian fees and expenses		481
Independent trustees' fees and expenses		9,608
Registration fees		37,551
Audit		27,791
Legal		1,867
Miscellaneous		8,513
Total expenses before reductions		1,236,073
Expense reductions		(356,735)
Total expenses after reductions				879,338
Net Investment income (loss)				73,686,708
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment Securities:
Unaffiliated issuers		(458,744,475)
Total net realized gain (loss)				(458,744,475)
Change in net unrealized appreciation (depreciation) on investment securities				(1,033,324,402)
Net gain (loss)				(1,492,068,877)
Net increase (decrease) in net assets resulting from operations			$	(1,418,382,169)

Statement of Changes in Net Assets

		Six months ended August 31, 2022 (Unaudited)		Year ended February 28, 2022
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$	73,686,708	$	74,369,825
Net realized gain (loss)		(458,744,475)		(13,042,389)
Change in net unrealized appreciation (depreciation)		(1,033,324,402)		(192,798,690)
Net increase (decrease) in net assets resulting from operations		(1,418,382,169)		(131,471,254)
Distributions to shareholders		(71,341,283)		(75,688,216)
Share transactions
Proceeds from sales of shares		2,938,884,520		9,113,616,478
Reinvestment of distributions		71,179,241		75,547,230
Cost of shares redeemed		(2,776,418,329)		(3,070,001,136)
Net increase (decrease) in net assets resulting from share transactions		233,645,432		6,119,162,572
Total increase (decrease) in net assets		(1,256,078,020)		5,912,003,102

Net Assets
Beginning of period		7,086,638,241		1,174,635,139
End of period	$	5,830,560,221	$	7,086,638,241

Other Information
Shares
Sold		314,114,977		826,731,045
Issued in reinvestment of distributions		7,872,304		6,792,550
Redeemed		(300,723,177)		(277,961,421)
Net increase (decrease)		21,264,104		555,562,174

Fidelity® SAI Long-Term Treasury Bond Index Fund

		Six months ended (Unaudited) August 31, 2022		Years ended February 28, 2022		2021		2020 A		2019		2018
Selected Per-Share Data
Net asset value, beginning of period	$	10.71	$	11.04	$	12.59	$	9.72	$	9.59	$	9.86
Income from Investment Operations
Net investment income (loss) B,C		.117		.219		.227		.251		.292		.278
Net realized and unrealized gain (loss)		(2.183)		(.309)		(.965)		2.876		.123		(.272)
Total from investment operations		(2.066)		(.090)		(.738)		3.127		.415		.006
Distributions from net investment income		(.114)		(.213)		(.226)		(.257)		(.285)		(.276)
Distributions from net realized gain		-		(.027)		(.586)		-		-		-
Total distributions		(.114)		(.240)		(.812)		(.257)		(.285)		(.276)
Net asset value, end of period	$	8.53	$	10.71	$	11.04	$	12.59	$	9.72	$	9.59
Total Return D,E		(19.35)%		(.85)%		(6.39)%		32.55%		4.38%		(.03)%
Ratios to Average Net Assets C,F,G
Expenses before reductions		.04% H		.08%		.05%		.08%		.20%		.18%
Expenses net of fee waivers, if any		.03% H		.03%		.03%		.03%		.03%		.06%
Expenses net of all reductions		.03% H		.03%		.03%		.03%		.03%		.06%
Net investment income (loss)		2.54% H		1.97%		1.77%		2.21%		2.99%		2.77%
Supplemental Data
Net assets, end of period (000 omitted)	$	5,830,560	$	7,086,638	$	1,174,635	$	1,055,440	$	60,238	$	825,447
Portfolio turnover rate I		105% H		62%		47%		18%		57%		128%

A For the year ended February 29.

B 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).

Notes to Financial Statements (Unaudited)

For the period ended August 31, 2022

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.

Fidelity Central Fund	Investment Manager	Investment Objective	Investment Practices	Expense Ratio A
Fidelity Money Market Central Funds	Fidelity Management & Research Company LLC (FMR)	Each fund seeks to obtain a high level of current income consistent with the preservation of capital and liquidity.	Short-term Investments	Less than .005%