# EDGAR Filing Document

**Accession Number:** 0000035315
**File Stem:** 0000035315-25-000626
**Filing Date:** 2025-7
**Character Count:** 3412
**Document Hash:** 550a1a888a102b45e078259945b0403b
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000035315-25-000626.hdr.sgml**: 20250711

**ACCESSION NUMBER**: 0000035315-25-000626

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 25

**FILED AS OF DATE**: 20250711

**DATE AS OF CHANGE**: 20250711

**EFFECTIVENESS DATE**: 20250711

**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:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-41839
- **FILM NUMBER:** 251117684

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

---

## 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           |

?xml version='1.0' encoding='ASCII'? Prospectus - Investment Objective

**Supplement to the Fidelity Flex® Funds Fidelity Flex® Mid Cap Index Fund and Fidelity Flex® Small Cap Index Fund June 28, 2025 Prospectus** 

The following information supplements information for Fidelity Flex® Mid Cap Index Fund found in the "Fund Summary" section under the "Principal Investment Strategies" heading.

* Beginning on July 17, 2025, the fund will transition from the Russell Midcap® Index to the Fidelity U.S. Mid Cap IndexSM using a blend of the two indices. The transition will be implemented through six equal stepped transitions effective at the market open on each of the following dates: July 17, 2025, July 24, 2025, July 31, 2025, August 7, 2025, August 14, 2025, and August 21, 2025. The fund's final transition to the Fidelity U.S. Mid Cap IndexSM will be completed at the market close on August 20, 2025.

The following information supplements information for Fidelity Flex® Mid Cap Index Fund found in the "Investment Details" section under the "Principal Investment Strategies" heading.

Beginning on July 17, 2025, the fund will transition from the Russell Midcap® Index to the Fidelity U.S. Mid Cap IndexSM using a blend of the two indices. The transition will be implemented through six equal stepped transitions effective at the market open on each of the following dates: July 17, 2025, July 24, 2025, July 31, 2025, August 7, 2025, August 14, 2025, and August 21, 2025. The fund's final transition to the Fidelity U.S. Mid Cap IndexSM will be completed at the market close on August 20, 2025.

ZMP-ZAP-PSTK-0725-103 1.9886010.103 July 11, 2025