Contents

(expenses that you pay each year as a % of the value of your investment)

Investment Adviser

Fidelity Management & Research Company LLC (FMR) (the Adviser) is the fund's manager. Other investment advisers serve as sub-advisers for the fund.

Portfolio Manager(s)

Brandon Bettencourt (Co-Portfolio Manager) has managed the fund since 2015.

Richard Munclinger (Co-Portfolio Manager) has managed the fund since 2020.

Purchase and Sale of Shares

NOT AVAILABLE FOR SALE TO THE GENERAL PUBLIC.

Shares are offered exclusively to certain clients of the Adviser or its affiliates.

The price to buy one share is its net asset value per share (NAV). Shares will be bought at the NAV next calculated after an order is received in proper form.

The price to sell one share is its NAV. Shares will be sold at the NAV next calculated after an order is received in proper form.

The fund is open for business each day the New York Stock Exchange (NYSE) is open.

There is no purchase minimum for fund shares.

Tax Information

Distributions you receive from the fund are subject to federal income tax and generally will be taxed as ordinary income or capital gains, and may also be subject to state or local taxes, unless you are investing through a tax-advantaged retirement account (in which case you may be taxed later, upon withdrawal of your investment from such account).

Payments to Broker-Dealers and Other Financial Intermediaries

The fund, the Adviser, Fidelity Distributors Company LLC (FDC), and/or their affiliates may pay intermediaries, which may include banks, broker-dealers, retirement plan sponsors, administrators, or service-providers (who may be affiliated with the Adviser or FDC), for the sale of fund shares and related services. These payments may create a conflict of interest by influencing your intermediary and your investment professional to recommend the fund over another investment. Ask your investment professional or visit your intermediary's web site for more information.

Fund Basics

Investment Details

Investment Objective

Fidelity® SAI Long-Term Treasury Bond Index Fund seeks a high level of current income.

Principal Investment Strategies

The fund seeks to replicate the performance of the Bloomberg U.S. 20+ Year Treasury Bond Index. The Adviser normally invests at least 80% of the fund's assets in securities included in the index. The index is composed of investment-grade fixed-rate public obligations of the U.S. Treasury with maturities of 20 years or more. The fund normally maintains a dollar-weighted average maturity that generally is expected to be 20 years or more, consistent with that of the index. As of February 29, 2024, the dollar-weighted average maturity of the index was 26.1 years.

The Adviser may use statistical sampling techniques to attempt to replicate the returns of the index using a smaller number of securities. Statistical sampling techniques attempt to match the investment characteristics of the index and the fund by taking into account such factors as duration, maturity, interest rate sensitivity, security structure, and credit quality.

The fund may not track the index because differences between the index and the fund's portfolio can cause differences in performance. In addition, expenses and transaction costs, the size and frequency of cash flows into and out of the fund, and differences between how and when the fund and the index are valued can cause differences in performance.

If the Adviser's strategies do not work as intended, the fund may not achieve its objective.

Description of Principal Security Types

Debt securities are used by issuers to borrow money. The issuer usually pays a fixed, variable, or floating rate of interest, and must repay the amount borrowed, usually at the maturity of the security. Some debt securities, such as zero coupon bonds, do not pay current interest but are sold at a discount from their face values. Debt securities include corporate bonds, government securities (including Treasury securities), repurchase agreements, money market securities, mortgage and other asset-backed securities, loans and loan participations, and other securities believed to have debt-like characteristics, including hybrids and synthetic securities.

U.S. Government securities are high-quality securities issued or guaranteed by the U.S. Treasury or by an agency or instrumentality of the U.S. Government. U.S. Government securities may be backed by the full faith and credit of the U.S. Treasury, the right to borrow from the U.S. Treasury, or the agency or instrumentality issuing or guaranteeing the security.

U.S. Government securities include mortgage and other asset-backed securities.

Derivatives are investments whose values are tied to an underlying asset, instrument, currency, or index. Derivatives include futures, options, forwards, and swaps, such as interest rate swaps (exchanging a floating rate for a fixed rate), total return swaps (exchanging a floating rate for the total return of an index, security, or other instrument or investment) and credit default swaps (buying or selling credit default protection).

Forward-settling securities   involve a commitment to purchase or sell specific securities when issued, or at a predetermined price or yield. Payment and delivery take place after the customary settlement period.

Principal Investment Risks

Many factors affect the fund's performance. Developments that disrupt global economies and financial markets, such as pandemics and epidemics, may magnify factors that affect a fund's performance. The fund's share price and yield change daily based on changes in market conditions and interest rates and in response to other economic, political, or financial developments. The fund's reaction to these developments will be affected by the types and maturities of securities in which the fund invests, the financial condition, industry and economic sector, and geographic location of an issuer, and the fund's level of investment in the securities of that issuer. Unlike individual debt securities, which typically pay principal at maturity, the value of an investment in the fund will fluctuate. When you sell your shares they may be worth more or less than what you paid for them, which means that you could lose money by investing in the fund.

The following factors can significantly affect the fund's performance:

Interest Rate Changes.   Debt securities, including money market securities, have varying levels of sensitivity to changes in interest rates. In general, the price of a debt security can fall when interest rates rise and can rise when interest rates fall. Securities with longer maturities and certain types of securities, such as mortgage securities and the securities of issuers in the financial services sector, can be more sensitive to interest rate changes, meaning the longer the maturity of a security, the greater the impact a change in interest rates could have on the security's price. Short-term and long-term interest rates do not necessarily move in the same amount or the same direction. Short-term securities tend to react to changes in short-term interest rates, and long-term securities tend to react to changes in long-term interest rates. Securities with floating interest rates can be less sensitive to interest rate changes, but may decline in value if their interest rates do not rise as much as interest rates in general. Securities whose payment at maturity is based on the movement of all or part of an index and inflation-protected debt securities may react differently from other types of debt securities. In market environments where interest rates are rising, issuers may be less willing or able to make principal and/or interest payments on securities when due. Although the transition process away from certain benchmark rates, including London Interbank Offered Rate (LIBOR) (an indicative measure of the average interest rate at which major global banks could borrow from one another), has become increasingly well-defined, any potential effects of the transition away from LIBOR and other benchmark rates on financial markets, a fund or the financial instruments in which a fund invests can be difficult to ascertain and may adversely impact a fund's performance.

Prepayment. Many types of debt securities, including mortgage securities, are subject to prepayment risk. Prepayment risk occurs when the issuer of a security can repay principal prior to the security's maturity. Securities subject to prepayment can offer less potential for gains during a declining interest rate environment and similar or greater potential for loss in a rising interest rate environment. In addition, the potential impact of prepayment features on the price of a debt security can be difficult to predict and result in greater volatility.

Issuer-Specific Changes. Changes in the financial condition of an issuer or counterparty, changes in specific economic or political conditions that affect a particular type of security or issuer, and changes in general economic or political conditions can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's credit quality or value. Entities providing credit support or a maturity-shortening structure also can be affected by these types of changes, and if the structure of a security fails to function as intended, the security could decline in value.

Correlation to Index. The performance of the fund and its index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, imperfect correlation between the fund's securities and those in its index, timing differences associated with additions to and deletions from its index, and changes in the component securities. In addition, the fund may not be able to invest in certain securities in its index or invest in them in the exact proportions in which they are represented in the index due to regulatory restrictions. The fund may not be fully invested at times, either as a result of cash flows into the fund or as a result of reserves of cash held by the fund to meet redemptions. The use of sampling techniques or futures or other derivative positions may affect the fund's ability to achieve close correlation with its index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

Passive Management Risk. An index fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, an index fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers. The structure and composition of an index fund's index will affect the performance, volatility, and risk of the index and, consequently, the performance, volatility, and risk of the fund.

Leverage Risk. Derivatives and forward-settling securities involve leverage because they can provide investment exposure in an amount exceeding the initial investment. Leverage can magnify investment risks and cause losses to be realized more quickly. A small change in the underlying asset, instrument, or index can lead to a significant loss. Forward-settling securities also involve the risk that a security will not be issued, delivered, or paid for when anticipated. Government legislation or regulation could affect the use of these transactions and could limit a fund's ability to pursue its investment strategies.

Other Investment Strategies

In addition to the principal investment strategies discussed above, the Adviser may invest the fund's assets in debt securities by investing in other funds.

The Adviser may also engage in transactions that have a leveraging effect on the fund, including investments in derivatives, regardless of whether the fund may own the asset, instrument, or components of the index underlying the derivative, and forward-settling securities. The fund's derivative investments may include interest rate swaps, total return swaps, credit default swaps, and futures contracts (both long and short positions) on securities and indexes. Depending on the Adviser's outlook and market conditions, the Adviser may engage in these transactions to increase or decrease the fund's exposure to changing security prices, interest rates, credit qualities, or other factors that affect security values, or to gain or reduce exposure to an asset, instrument, or index.

Fundamental Investment Policies

The following is fundamental, that is, subject to change only by shareholder approval:

Fidelity® SAI Long-Term Treasury Bond Index Fund seeks a high level of current income.

Shareholder Notice

The following is subject to change only upon 60 days' prior notice to shareholders:

Fidelity® SAI Long-Term Treasury Bond Index Fund   normally invests at least 80% of its assets in U.S. Treasury securities included in the Bloomberg U.S. 20+ Year Treasury Bond Index.

Valuing Shares

The fund is open for business each day the NYSE is open.

The NAV is the value of a single share. Fidelity normally calculates NAV as of the close of business of the NYSE, normally 4:00 p.m. Eastern time. The fund's assets normally are valued as of this time for the purpose of computing NAV.

NAV is not calculated and the fund will not process purchase and redemption requests submitted on days when the fund is not open for business. The time at which shares are priced and until which purchase and redemption orders are accepted may be changed as permitted by the Securities and Exchange Commission (SEC).

To the extent that the fund's assets are traded in other markets on days when the fund is not open for business, the value of the fund's assets may be affected on those days. In addition, trading in some of the fund's assets may not occur on days when the fund is open for business.

NAV is calculated using the values of other open-end funds, if any, in which the fund invests (referred to as underlying funds). Shares of underlying funds are valued at their respective NAVs. Other assets are valued primarily on the basis of market quotations, official closing prices, or information furnished by a pricing service. Certain short-term securities are valued on the basis of amortized cost. If market quotations, official closing prices, or information furnished by a pricing service are not readily available or, in the Adviser's opinion, are deemed unreliable for a security, then that security will be fair valued in good faith by the Adviser in accordance with applicable fair value pricing policies. For example, if, in the Adviser's opinion, a security's value has been materially affected by events occurring before a fund's pricing time but after the close of the exchange or market on which the security is principally traded, then that security will be fair valued in good faith by the Adviser in accordance with applicable fair value pricing policies. Fair value pricing will be used for high yield debt securities when available pricing information is determined to be stale or for other reasons not to accurately reflect fair value.

Arbitrage opportunities may exist when trading in a portfolio security or securities is halted and does not resume before a fund calculates its NAV. These arbitrage opportunities may enable short-term traders to dilute the NAV of long-term investors. Securities trading in overseas markets, if applicable, present time zone arbitrage opportunities when events affecting portfolio security values occur after the close of the overseas markets but prior to the close of the U.S. market. Fair valuation of a fund's portfolio securities can serve to reduce arbitrage opportunities available to short-term traders, but there is no assurance that fair value pricing policies will prevent dilution of NAV by short-term traders.

Fair value pricing is based on subjective judgments and it is possible that the fair value of a security may differ materially from the value that would be realized if the security were sold.

Shareholder Information

Additional Information about the Purchase and Sale of Shares

NOT AVAILABLE FOR SALE TO THE GENERAL PUBLIC.

As used in this prospectus, the term "shares" generally refers to the shares offered through this prospectus.

Shares are offered exclusively to certain clients of the Adviser or its affiliates. If you are not currently a client in a discretionary investment program offered by the Adviser or its affiliates, please call 1-800-544-3455 (9:00 a.m. - 6:00 p.m. Eastern time, Monday through Friday) for more information. Additional fees apply for discretionary investment programs. For more information on these fees, please refer to the "Buying and Selling Information" section of the Statement of Additional Information (SAI). 

The fund may reject for any reason, or cancel as permitted or required by law, any purchase orders.

Excessive trading of fund shares can harm shareholders in various ways, including reducing the returns to long-term shareholders by increasing costs to the fund (such as brokerage commissions or spreads paid to dealers who sell money market instruments), disrupting portfolio management strategies, and diluting the value of the shares in cases in which fluctuations in markets are not fully priced into the fund's NAV.

Because investments in the fund can only be made by the Adviser or an affiliate on behalf of its clients, the potential for excessive or short-term disruptive purchases and sales is reduced. Accordingly, the Board of Trustees has not adopted policies and procedures designed to discourage excessive trading of fund shares and the fund accommodates frequent trading.  

The fund does not place a limit on purchases or sales of fund shares by the Adviser or its affiliates. The fund reserves the right, but does not have the obligation, to reject any purchase transaction at any time. In addition, the fund reserves the right to impose restrictions on disruptive, excessive, or short-term trading. 

The fund has no exchange privilege with any other fund.

There is no minimum balance or purchase minimum for fund shares.

The price to buy one share is its NAV. Shares are sold without a sales charge.

Shares will be bought at the NAV next calculated after an order is received in proper form.

Shares are generally available only to investors residing in the United States.

The fund may stop offering shares completely or may offer shares only on a limited basis, for a period of time or permanently.

Under applicable anti-money laundering rules and other regulations, purchase orders may be suspended, restricted, or canceled and the monies may be withheld.

The price to sell one share is its NAV.

Shares will be sold at the NAV next calculated after an order is received in proper form.

Normally, redemptions will be processed by the next business day, but it may take up to seven days to pay the redemption proceeds if making immediate payment would adversely affect the fund.

See "Policies Concerning the Redemption of Fund Shares" below for additional redemption information.

Redemptions may be suspended or payment dates postponed when the NYSE is closed (other than weekends or holidays), when trading on the NYSE is restricted, or as permitted by the SEC.

Redemption proceeds may be paid in securities or other property rather than in cash if the Adviser determines it is in the best interests of the fund.

When you terminate your relationship with the Adviser, or one of its affiliates, your shares may be sold at the NAV next calculated, in which case proceeds from such redemption would be sent to you.

Under applicable anti-money laundering rules and other regulations, redemption requests may be suspended, restricted, canceled, or processed and the proceeds may be withheld.

If applicable, orders by funds of funds for which the Adviser or its affiliates serve as investment manager will be treated as received by the fund at the same time that the corresponding orders are received in proper form by the funds of funds.

Policies Concerning the Redemption of Fund Shares

If your account is held directly with a fund , the length of time that a fund typically expects to pay redemption proceeds depends on the method you have elected to receive such proceeds. A fund typically expects to make payment of redemption proceeds by wire, automated clearing house (ACH) or by issuing a check by the next business day following receipt of a redemption order in proper form. Proceeds from the periodic and automatic sale of shares of a Fidelity ® money market fund that are used to buy shares of another Fidelity ® fund are settled simultaneously.

If your account is held through an intermediary , the length of time that a fund typically expects to pay redemption proceeds depends, in part, on the terms of the agreement in place between the intermediary and a fund. For redemption proceeds that are paid either directly to you from a fund or to your intermediary for transmittal to you, a fund typically expects to make payments by wire, by ACH or by issuing a check on the next business day following receipt of a redemption order in proper form from the intermediary by a fund. Redemption orders that are processed through investment professionals that utilize the National Securities Clearing Corporation will generally settle one to three business days following receipt of a redemption order in proper form.

As noted elsewhere, payment of redemption proceeds may take longer than the time a fund typically expects and may take up to seven days from the date of receipt of the redemption order as permitted by applicable law.

Redemption Methods Available. Generally a fund expects to pay redemption proceeds in cash. To do so, a fund typically expects to satisfy redemption requests either by using available cash (or cash equivalents) or by selling portfolio securities. On a less regular basis, a fund may also satisfy redemption requests by utilizing one or more of the following sources, if permitted: borrowing from another Fidelity ® fund; drawing on an available line or lines of credit from a bank or banks; or using reverse repurchase agreements. These methods may be used during both normal and stressed market conditions.

In addition to paying redemption proceeds in cash, a fund reserves the right to pay part or all of your redemption proceeds in readily marketable securities instead of cash (redemption in-kind). Redemption in-kind proceeds will typically be made by delivering the selected securities to the redeeming shareholder within seven days after the receipt of the redemption order in proper form by a fund.

Dividends and Capital Gain Distributions

The fund earns interest, dividends, and other income from its investments, and distributes this income (less expenses) to shareholders as dividends. The fund also realizes capital gains from its investments, and distributes these gains (less any losses) to shareholders as capital gain distributions.

The fund normally declares dividends and pays capital gain distributions per the tables below:

Earning Dividends 

The fund processes purchase and redemption requests only on days it is open for business. 

Shares generally begin to earn dividends on the first business day following the day of purchase. 

Shares generally earn dividends until, but not including, the next business day following the day of redemption. 

Distribution Options  

Any dividends and capital gain distributions may be reinvested in additional shares or paid in cash. 

Tax Consequences

As with any investment, your investment in the fund could have tax consequences for you (for non-retirement accounts).

Taxes on Distributions

Distributions you receive from the fund are subject to federal income tax, and may also be subject to state or local taxes. A portion of the fund's dividends may be exempt from state and local taxation to the extent that they are derived from certain U.S. Government securities and meet certain requirements.

For federal tax purposes, certain distributions, including dividends and distributions of short-term capital gains, are taxable to you as ordinary income, while certain distributions, including distributions of long-term capital gains, are taxable to you generally as capital gains. Because the fund's income is primarily derived from interest, dividends from the fund generally will not qualify for the long-term capital gains tax rates available to individuals. 

If the Adviser buys shares on your behalf when a fund has realized but not yet distributed income or capital gains, you will be "buying a dividend" by paying the full price for the shares and then receiving a portion of the price back in the form of a taxable distribution.

Any taxable distributions you receive from the fund will normally be taxable to you when you receive them, regardless of your distribution option.

If you elect to receive distributions in cash, you will receive certain December distributions in January, but those distributions will be taxable as if you received them on December 31.

Taxes on Transactions

Your redemptions may result in a capital gain or loss for federal tax purposes. A capital gain or loss on your investment in the fund generally is the difference between the cost of your shares and the price you receive when you sell them.

Fund Services

Fund Management

The fund is a mutual fund, an investment that pools shareholders' money and invests it toward a specified goal.

Adviser

FMR. The Adviser is the fund's manager. The address of the Adviser is 245 Summer Street, Boston, Massachusetts 02210.

As of December 31, 2023, the Adviser had approximately $3. 9 trillion in discretionary assets under management, and approximately $4.9 trillion when combined with all of its affiliates' assets under management.

As the manager, the Adviser has overall responsibility for directing the fund's investments and handling its business affairs.

Sub-Adviser(s)

FMR Investment Management (UK) Limited (FMR UK) , at 1 St. Martin's Le Grand, London, EC1A 4AS, United Kingdom, serves as a sub-adviser for the fund. As of December 31, 2023, FMR UK had approximately $14. 6 billion in discretionary assets under management. FMR UK is an affiliate of the Adviser.

FMR UK may provide investment research and advice on issuers based outside the United States and may also provide investment advisory services for the fund.

Fidelity Management & Research (Hong Kong) Limited (FMR H.K.) , at Floor 19, 41 Connaught Road Central, Hong Kong, serves as a sub-adviser for the fund. As of December 31, 2023, FMR H.K. had approximately $24.4 billion in discretionary assets under management. FMR H.K. is an affiliate of the Adviser.

FMR H.K. may provide investment research and advice on issuers based outside the United States and may also provide investment advisory services for the fund.

Fidelity Management & Research (Japan) Limited (FMR Japan) , at Kamiyacho Prime Place, 1-17, Toranomon-4-Chome, Minato-ku, Tokyo, Japan, serves as a sub-adviser for the fund. As of March 31, 2023, FMR Japan had approximately $2.9 billion in discretionary assets under management. FMR Japan is an affiliate of the Adviser.

FMR Japan may provide investment research and advice on issuers based outside the United States and may also provide investment advisory services for the fund.

Portfolio Manager(s)

Brandon Bettencourt is Co-Portfolio Manager of Fidelity ® SAI Long-Term Treasury Bond Index Fund, which he has managed since 2015. He also manages other funds. Since joining Fidelity Investments in 2008, Mr. Bettencourt has worked as a research associate, portfolio analyst, and portfolio manager.

Richard Munclinger is Co-Portfolio Manager of Fidelity ® SAI Long-Term Treasury Bond Index Fund, which he has managed since 2020. He also manages other funds. Since joining Fidelity Investments in 2016, Mr. Munclinger has worked as a quantitative analyst and portfolio manager.

The SAI provides additional information about the compensation of, any other accounts managed by, and any fund shares held by the portfolio manager(s). 

From time to time a manager, analyst, or other Fidelity employee may express views regarding a particular company, security, industry, or market sector. The views expressed by any such person are the views of only that individual as of the time expressed 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 fund are based on numerous factors, may not be relied on as an indication of trading intent on behalf of any fund. 

Advisory Fee(s)

The fund pays a management fee to the Adviser.

The management fee is calculated and paid to the Adviser every month.

The annual management fee rate, as a percentage of the fund's average net assets, is shown in the following table:

The Adviser pays FMR Investment Management (UK) Limited, Fidelity Management & Research (Hong Kong) Limited, and Fidelity Management & Research (Japan) Limited for providing sub-advisory services.

The basis for the Board of Trustees approving the management contract and sub-advisory agreements for the fund is available in the fund's annual report for the fiscal period ended February 29, 2024.

From time to time, the Adviser or its affiliates may agree to reimburse or waive certain fund expenses while retaining the ability to be repaid if expenses fall below the specified limit prior to the end of the fiscal year.

Reimbursement or waiver arrangements can decrease expenses and boost performance.

Fund Distribution

FDC distributes the fund's shares.

Distribution and Service Plan(s)

The fund has adopted a Distribution and Service Plan pursuant to Rule 12b-1 under the Investment Company Act of 1940 (1940 Act) with respect to its shares that recognizes that the Adviser may use its management fee revenues, as well as its past profits or its resources from any other source, to pay FDC for expenses incurred in connection with providing services intended to result in the sale of shares of the fund and/or shareholder support services. The Adviser, directly or through FDC, may pay significant amounts to intermediaries that provide those services. Currently, the Board of Trustees of the fund has authorized such payments for shares of the fund.

Affiliates of the Adviser may receive service fees or distribution fees or both with respect to underlying funds that participate in Fidelity's FundsNetwork ® .

If payments made by the Adviser to FDC or to intermediaries under the Distribution and Service Plan were considered to be paid out of the fund's assets on an ongoing basis, they might increase the cost of your investment and might cost you more than paying other types of sales charges.

No dealer, sales representative, or any other person has been authorized to give any information or to make any representations, other than those contained in this prospectus and in the related SAI, in connection with the offer contained in this prospectus. If given or made, such other information or representations must not be relied upon as having been authorized by the fund or FDC. This prospectus and the related SAI do not constitute an offer by the fund or by FDC to sell shares of the fund to, or to buy shares of the fund from, any person to whom it is unlawful to make such offer.

Appendix

Financial Highlights

Financial Highlights are intended to help you understand the financial history of fund shares for the past 5 years (or, if shorter, the period of operations). Certain information reflects financial results for a single share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in shares (assuming reinvestment of all dividends and distributions). The annual information has been audited by Deloitte & Touche LLP, independent registered public accounting firm, whose report , along with fund financial statements, is included in the annual report. Annual reports are available for free upon request. 

Fidelity® SAI Long-Term Treasury Bond Index Fund

A For the year ended February 29.

B 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 mutual funds or ETFs is not included in the Fund's net investment income (loss) ratio.

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.

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 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.

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

Additional Index Information

Bloomberg U.S. 20+ Year Treasury Bond Index   is a market value-weighted index of investment-grade fixed-rate public obligations of the U.S. Treasury with maturities equal to or greater than 20 years.

"Bloomberg ® " and the index or indices are service marks of Bloomberg Finance L.P. and its affiliates, including Bloomberg Index Services Limited ("BISL"), the administrator of the index (collectively, "Bloomberg"), and have been licensed for use for certain purposes by the Adviser. 

The fund(s) are not sponsored, endorsed, sold or promoted by Bloomberg. Bloomberg does not make any representation or warranty, express or implied, to the owners of or counterparties to the fund(s) or any member of the public regarding the advisability of investing in securities generally or in the fund(s) particularly. The only relationship of Bloomberg to the Adviser is the licensing of certain trademarks, trade names and service marks and of the index or indices, which is determined, composed and calculated by BISL without regard to the Adviser or the fund(s). Bloomberg has no obligation to take the needs of the Adviser or the owners of the fund(s) into consideration in determining, composing or calculating the index or indices. Bloomberg is not responsible for and has not participated in the determination of the timing of, prices at, or quantities of the fund(s) to be issued. Bloomberg shall not have any obligation or liability, including, without limitation, to fund(s) customers, in connection with the administration, marketing or trading of the fund(s). 

BLOOMBERG DOES NOT GUARANTEE THE ACCURACY AND/OR THE COMPLETENESS OF THE INDEX OR INDICES OR ANY DATA RELATED THERETO AND SHALL HAVE NO LIABILITY FOR ANY ERRORS, OMISSIONS OR INTERRUPTIONS THEREIN. BLOOMBERG DOES NOT MAKE ANY WARRANTY, EXPRESS OR IMPLIED, AS TO RESULTS TO BE OBTAINED BY THE ADVISER, OWNERS OF THE FUND(S) OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE INDEX OR INDICES OR ANY DATA RELATED THERETO. BLOOMBERG DOES NOT MAKE ANY EXPRESS OR IMPLIED WARRANTIES AND EXPRESSLY DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE WITH RESPECT TO THE INDEX OR INDICES OR ANY DATA RELATED THERETO. WITHOUT LIMITING ANY OF THE FOREGOING, TO THE MAXIMUM EXTENT ALLOWED BY LAW, BLOOMBERG, ITS LICENSORS, AND ITS AND THEIR RESPECTIVE EMPLOYEES, CONTRACTORS, AGENTS, SUPPLIERS, AND VENDORS SHALL HAVE NO LIABILITY OR RESPONSIBILITY WHATSOEVER FOR ANY INJURY OR DAMAGES-WHETHER DIRECT, INDIRECT, CONSEQUENTIAL, INCIDENTAL, PUNITIVE OR OTHERWISE-ARISING IN CONNECTION WITH THE FUND(S) OR INDEX OR INDICES OR ANY DATA OR VALUES RELATING THERETO-WHETHER ARISING FROM THEIR NEGLIGENCE OR OTHERWISE, EVEN IF NOTIFIED OF THE POSSIBILITY THEREOF. 

IMPORTANT INFORMATION ABOUT OPENING A NEW ACCOUNT

To help the government fight the funding of terrorism and money laundering activities, the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT ACT), requires all financial institutions to obtain, verify, and record information that identifies each person or entity that opens an account.
For individual investors opening an account: When you open an account, you will be asked for your name, address, date of birth, and other information that will allow Fidelity to identify you. You may also be asked to provide documents that may help to establish your identity, such as your driver's license.
For investors other than individuals:   When you open an account, you will be asked for the name of the entity, its principal place of business and taxpayer identification number (TIN). You will be asked to provide information about the entity's control person and beneficial owners, and person(s) with authority over the account, including name, address, date of birth and social security number. You may also be asked to provide documents, such as drivers' licenses, articles of incorporation, trust instruments or partnership agreements and other information that will help Fidelity identify the entity.

You can obtain additional information about the fund. A description of the fund's policies and procedures for disclosing its holdings is available in its Statement of Additional Information (SAI) and on Fidelity's web sites. The SAI also includes more detailed information about the fund and its investments. The SAI is incorporated herein by reference (legally forms a part of the prospectus). The fund's annual and semi-annual reports also include additional information. The fund's annual report includes a discussion of the fund's holdings and recent market conditions and the fund's investment strategies that affected performance.

For a free copy of any of these documents or to request other information or ask questions about the fund, call Fidelity at 1-800-544-3455. In addition, you may visit Fidelity's web site at www.fidelity.com for a free copy of a prospectus, SAI, or annual or semi-annual report or to request other information.

Fidelity Distributors Company LLC (FDC) is a member of the Securities Investor Protection Corporation (SIPC). You may obtain information about SIPC, including the SIPC brochure, by visiting www.sipc.org or calling SIPC at 202-371-8300.

Fidelity, the Fidelity Investments Logo and all other Fidelity trademarks or service marks used herein are trademarks or service marks of FMR LLC. Any third-party marks that are used herein are trademarks or service marks of their respective owners. © 2024 FMR LLC. All rights reserved.