# EDGAR Filing Document

**Accession Number:** 0000035315
**File Stem:** 0000035315-25-000585
**Filing Date:** 2025-6
**Character Count:** 16949
**Document Hash:** 149e5e612c000f6cfa593fe8689b0a9c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000035315-25-000585.hdr.sgml**: 20250627

**ACCESSION NUMBER**: 0000035315-25-000585

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20250627

**DATE AS OF CHANGE**: 20250627

**EFFECTIVENESS DATE**: 20250627

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** FIDELITY SALEM STREET TRUST
- **CENTRAL INDEX KEY:** 0000035315

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 0430

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-41839
- **FILM NUMBER:** 251083611

**BUSINESS ADDRESS:**
- **STREET 1:** 245 SUMMER STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02210
- **BUSINESS PHONE:** 617-563-7000

**MAIL ADDRESS:**
- **STREET 1:** 245 SUMMER STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02210

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FIDELITY FIXED INCOME TRUST
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FIDELITY FLEXIBLE BOND FUND
- **DATE OF NAME CHANGE:** 19860904

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FIDELITY CORPORATE BOND FUND INC
- **DATE OF NAME CHANGE:** 19851225

## Series and Classes Contracts Data

### Fidelity Flex Mid Cap Index Fund (Series ID: S000056358)

| Class ID   | Class Name                       | Ticker Symbol   |
|:---|:---|:---|
| C000177585 | Fidelity Flex Mid Cap Index Fund | FLAPX           |

Fidelity Flex® Funds

**<u>Fund</u>**<u>/Ticker</u>

**Fidelity Flex® Mid Cap Index Fund**/FLAPX

**Summary Prospectus**

**June 28, 2025**

Before you invest, you may want to review the fund's prospectus, which contains more information about the fund and its risks. You can find the fund's prospectus, reports to shareholders, and other information about the fund (including the fund's SAI) online at fundresearch.fidelity.com/prospectus/sec. You can also get this information at no cost by calling 1-800-835-5095 or by sending an e-mail request to fidfunddocuments@fidelity.com. The fund's prospectus and SAI dated June 28, 2025 are incorporated herein by reference.

![](img109333_1.jpg)

245 Summer Street, Boston, MA 02210

**Fund Summary**

**Fund:**

**Fidelity Flex® Mid Cap Index Fund**

**Investment Objective**

Fidelity Flex® Mid Cap Index Fund seeks to provide investment results that correspond to the total return of stocks of mid-capitalization U.S. companies.

**Fee Table**

The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. **You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.**

**Shareholder fees**

---

| | |
|:---|:---|
| **(fees paid directly from your investment)** | **None** |

---

**Annual Operating Expenses**

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

---

| | |
|:---|:---|
| Management fee  | 0.00%  |
| Distribution and/or Service (12b-1) fees |  |
| Other expenses | 0.00%  |
| **Total annual operating expenses** | 0.00% A |

---

AThe fund is available only to certain fee-based accounts and advisory programs offered by Fidelity. Advisory account clients, retirement plans, plan sponsors and/or plan participants typically pay an advisory fee that generally covers investment advisory and administrative services.

This **example** helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. This example does not include any fees paid at the fee-based account or plan level. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

---

| | |
|:---|:---|
| 1 year | $0 |
| 3 years | $0 |
| 5 years | $0 |
| 10 years | $0 |

---

**Portfolio Turnover**

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 17% of the average value of its portfolio.

**Principal Investment Strategies**

* Prior to August 21, 2025, normally investing at least 80% of assets in securities included in the Russell Midcap® Index.

The Russell Midcap® Index is a market capitalization-weighted index of medium-capitalization U.S. company stocks.

* Effective August 21, 2025, normally investing at least 80% of assets in securities included in the Fidelity U.S. Mid Cap IndexSM.

The Fidelity U.S. Mid Cap IndexSM is a float-adjusted market capitalization-weighted index designed to reflect the performance of stocks of U.S. mid-capitalization companies. It is a subset of the Fidelity U.S. Total Investable Market IndexSM (a float-adjusted market capitalization-weighted index designed to reflect the performance for the U.S. equity market, including large-, mid-, and small-capitalization stocks). Mid-capitalization stocks are considered to be stocks whose market capitalization is similar to the market capitalization of companies in the Russell Midcap® Index or the S&P MidCap 400® Index.

Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.

* Lending securities to earn income for the fund.

**Principal Investment Risks**

* *Stock Market Volatility.*

Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

* *Issuer-Specific Changes.*

The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.

Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

* *Correlation to Index.*

The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the 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.*

The 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, the 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.

* *Rules-Based Strategy Risk.*

Although the index uses a rules-based proprietary index methodology, there is no guarantee that this methodology will be successful.

* *Mid Cap Investing.*

The value of securities of medium size, less well-known issuers can perform differently from the market as a whole and other types of stocks and can be more volatile than that of larger issuers.

* *Securities Lending Risk.*

Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.

*An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency*. *You could lose money by investing in the fund.*

**Performance**

The following information is intended to help you understand the risks of investing in the fund.

The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance.

The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level.

Visit www.401k.com and log in or www.fidelity.com for more recent performance information.

**Year-by-Year Returns** 

---

| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 |
| *-*9.01%<br>| 30.56%<br>| 17.29%<br>| 22.58%<br>| *-*17.29%<br>| 17.30%<br>| 15.28%<br>|

---

![](img109333_4.jpg)

---

| | | |
|:---|:---|:---|
| *During the periods shown in the chart:* | *Returns* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*Quarter ended* |
| *Highest Quarter Return* | *24.64%* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*June 30, 2020* |
| *Lowest Quarter Return* | *-26.96%* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*March 31, 2020* |
| *Year-to-Date Return* | *-3.41%* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*March 31, 2025* |

---

**Average Annual Returns**

After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

---

| | | | |
|:---|:---|:---|:---|
| <br> For the periods ended December 31, 2024 | &nbsp;&nbsp;Past 1<br> year | &nbsp;&nbsp;Past 5<br> years | Life of<br> fund  |
| **Fidelity Flex® Mid Cap Index Fund** |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;**Return Before Taxes**  | &nbsp;&nbsp;15.28%  | &nbsp;&nbsp;9.97%  | &nbsp;&nbsp;10.47% A |
| &nbsp;&nbsp;&nbsp;&nbsp;**Return After Taxes on Distributions**  | &nbsp;&nbsp;14.99%  | &nbsp;&nbsp;9.40%  | &nbsp;&nbsp;9.91% A |
| &nbsp;&nbsp;&nbsp;&nbsp;**Return After Taxes on Distributions and Sale of Fund Shares** <br>| &nbsp;&nbsp;9.26%  | &nbsp;&nbsp;7.78%  | &nbsp;&nbsp;8.36% A |
| Russell Midcap® Index<br> **(reflects no deduction for fees, expenses, or taxes)** | &nbsp;&nbsp; <br> 15.34%  | &nbsp;&nbsp; <br> 9.92%  | &nbsp;&nbsp; <br> 10.43%  |
| Russell 1000® Index<br> **(reflects no deduction for fees, expenses, or taxes)** | &nbsp;&nbsp; <br> 24.51%  | &nbsp;&nbsp; <br> 14.28%  | &nbsp;&nbsp; <br> 14.08%  |

---

A*From March 9, 2017.*

Beginning August 21, 2025, the fund will begin comparing its performance to the Fidelity U.S. Mid Cap IndexSM rather than the Russell Midcap® Index because the Fidelity U.S. Mid Cap IndexSM conforms more closely to the fund's investment policies.

The fund has begun comparing its performance to the Russell 1000® Index to satisfy a new Securities and Exchange Commission (SEC) disclosure requirement.

**Investment Adviser**

Fidelity Management & Research Company LLC (FMR) (the Adviser) is the fund's manager. Geode Capital Management, LLC serves as a sub-adviser for the fund.

**Portfolio Manager(s)**

Louis Bottari (Senior Portfolio Manager) has managed the fund since 2017.

Peter Matthew (Senior Portfolio Manager) has managed the fund since 2017.

Navid Sohrabi (Senior Portfolio Manager) has managed the fund since 2019.

Robert Regan (Portfolio Manager) has managed the fund since 2017.

Payal Gupta (Portfolio Manager) has managed the fund since 2019.

**Purchase and Sale of Shares**

Shares are available only to certain fee-based accounts and advisory programs offered by Fidelity. Shares also may be available to certain broker-dealers that have entered into arrangements with Fidelity.

You may buy or sell shares in various ways:

**Internet**

---

| | |
|:---|:---|
| **<u>Plan Accounts:</u>** | **<u>All Other Accounts:</u>** |
| **www.401k.com** | **www.fidelity.com** |

---

**Phone**

**<u>Plan Accounts:</u>**

**For Individual Accounts (investing through a retirement plan sponsor or other institution), refer to your plan materials or contact that institution directly.**

**For Retirement Plan Level Accounts:**

**Corporate Clients 1-800-962-1375**

**"Not for Profit" Clients 1-800-343-0860**

**<u>All Other Accounts:</u>**

**1-800-544-3455**

**Mail (Plan Accounts Only)**

---

| | |
|:---|:---|
| **Redemptions:**<br> **Fidelity Investments**<br> **P.O. Box 770001**<br> **Cincinnati, OH 45277-0035** | ***Overnight Express:***<br> **Fidelity Investments**<br> **100 Crosby Parkway**<br> **Covington, KY 41015** |

---

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 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. Currently, the Board of Trustees of the fund has not authorized such payments for shares of the fund. Ask your investment professional or visit your intermediary's web site for more information.

The fund is not in any way connected to or sponsored, endorsed, sold or promoted by Frank Russell Company ("Russell") or by the London Stock Exchange Group plc and its group undertakings (collectively, the "LSE Group"). The LSE Group does not accept any liability whatsoever to any person arising out of the use of a fund or the underlying data.

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.© 2025 FMR LLC. All rights reserved.

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