# EDGAR Filing Document

**Accession Number:** 0000225322
**File Stem:** 0000225322-25-000249
**Filing Date:** 2025-7
**Character Count:** 18432
**Document Hash:** 7bbe147b929d4b045a30a358a8a139ac
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000225322-25-000249.hdr.sgml**: 20250729

**ACCESSION NUMBER**: 0000225322-25-000249

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20250729

**DATE AS OF CHANGE**: 20250729

**EFFECTIVENESS DATE**: 20250729

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** FIDELITY SUMMER STREET TRUST
- **CENTRAL INDEX KEY:** 0000225322

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

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-58542
- **FILM NUMBER:** 251158877

**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 HIGH INCOME FUND
- **DATE OF NAME CHANGE:** 19890309

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FIDELITY AGGRESSIVE INCOME FUND
- **DATE OF NAME CHANGE:** 19810205

## Series and Classes Contracts Data

### Fidelity Water Sustainability Fund (Series ID: S000067937)

| Class ID   | Class Name                         | Ticker Symbol   |
|:---|:---|:---|
| C000217779 | Fidelity Water Sustainability Fund | FLOWX           |

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

**Fidelity® Water Sustainability Fund**/FLOWX

**Summary Prospectus**

**July 30, 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-FIDELITY or by sending an e-mail request to fidfunddocuments@fidelity.com. The fund's prospectus and SAI dated July 30, 2025 are incorporated herein by reference.

![](img109816_1.jpg)

245 Summer Street, Boston, MA 02210

**Fund Summary**

**Fund:**

**Fidelity® Water Sustainability Fund**

**Investment Objective**

Fidelity® Water Sustainability Fund seeks long-term growth of capital.

**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  | 0.82%  |
| Distribution and/or Service (12b-1) fees |  |
| Other expenses | 0.10%  |
| **Total annual operating expenses** | 0.92%  |

---

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. 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 | $94 |
| 3 years | $293 |
| 5 years | $509 |
| 10 years | $1131 |

---

**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 37% of the average value of its portfolio.

**Principal Investment Strategies**

* Normally investing at least 80% of assets in securities of water sustainability companies.

Water sustainability companies include those contained in the S&P® Global Water Index or those that, in Fidelity Management & Research Company LLC's (FMR) (the Adviser) opinion, are developing efficiencies, extending the life cycle and/or identifying affordable new technologies to deliver safe, reliable or easily accessible water.

Such companies may include but are not limited to companies principally engaged in water resources, water treatment, water distribution and utilities, desalinization or purification facilities, water technologies and analytics, environmental water services and water infrastructure (pumps, valves, meters, pipes), irrigation, water conservation services, and water supply or processing services.

For purposes of the fund's policy to normally invest at least 80% of its assets in securities of companies principally engaged in the business activity or activities identified for the fund, Fidelity may consider a company to be principally engaged in the designated business activity or activities based on: (i) the level of a company's assets, income, sales, or profits that are committed to, derived from, or related to the designated business activity or activities, or (ii) whether a third party has given the company an industry or sector classification consistent with the designated business activity or activities. Whether a company is principally engaged in the designated business activity or activities can be determined under any of these factors.

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.

* Normally investing primarily in equity securities.

* Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.

* Investing in either "growth" stocks or "value" stocks or both.

* Investing in securities of domestic and foreign issuers.

* Employing sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from, certain industries. Please see "Fund Basics - Investment Details - Sustainable Investing Exclusions" for additional information.

**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.

* *Sustainability Risk.*

Application of Fidelity Management & Research Company LLC's (FMR) (the Adviser) environmental, social and governance (ESG) ratings process and/or its sustainable investing exclusion criteria may affect the fund's exposure to certain issuers, sectors, regions, and countries and may affect the fund's performance depending on whether certain investments are in or out of favor. The criteria related to the fund's ESG ratings process and/or adherence to its sustainable investing exclusion criteria may result in the fund forgoing opportunities to buy certain securities when it might otherwise be advantageous to do so, or selling securities for ESG reasons when it might be otherwise disadvantageous for it to do so. As a result, the fund's performance may at times be better or worse than the performance of funds that do not use ESG or sustainability criteria. There are significant differences in interpretations of what it means for an issuer to have positive ESG factors. While the Adviser believes its definitions are reasonable, the portfolio decisions it makes may differ with other investors' or advisers' views. When evaluating an issuer, the Adviser is dependent on information or data obtained through voluntary or third-party reporting that may be incomplete, inaccurate, or unavailable, which could cause the Adviser to incorrectly assess an issuer's business practices.

* *Foreign and Emerging Markets Risk.*

Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.

The extent of economic development; political stability; market depth, infrastructure, and capitalization; and regulatory oversight can be less than in more developed markets. Emerging markets typically have less established legal, accounting and financial reporting systems than those in more developed markets, which may reduce the scope or quality of financial information available to investors.

Emerging markets can be subject to greater social, economic, regulatory, and political uncertainties and can be extremely volatile.

Foreign exchange rates also can be extremely volatile.

* *Geographic Exposure to Europe.*

Because the fund invests a meaningful portion of its assets in Europe, the fund's performance is expected to be closely tied to social, political, and economic conditions within Europe and to be more volatile than the performance of more geographically diversified funds.

* *Water Sustainability Industry Concentration.*

The water sustainability theme can be significantly affected by demographic, irrigation and industrial usage trends, viability of infrastructure projects, conservation practices, pollution, waste, and environmental factors, including weather, droughts, flooding, as well as the performance of the overall economy, interest rates, consumer confidence, and the cost of commodities. Regulations and policies of various domestic and foreign governments may affect water usage, contamination, and reusability.

* *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.

The value of securities of smaller issuers can be more volatile than that of larger issuers.

* *"Growth" Investing.*

"Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.

* *"Value" Investing.*

"Value" stocks can perform differently from the market as a whole and other types of stocks and can continue to be undervalued by the market for long periods of time.

* *Management Risk.*

The Adviser's application of the fund's strategy criteria may not achieve its intended results. The fund could underperform in comparison to other funds with a similar benchmark or similar objectives and investment strategies.

*In addition, the fund is classified as non-diversified under the Investment Company Act of 1940 (1940 Act), which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.*

*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.

Visit www.fidelity.com for more recent performance information.

**Year-by-Year Returns** 

---

| | | | |
|:---|:---|:---|:---|
| 2021 | 2022 | 2023 | 2024 |
| 28.52%<br>| *-*19.94%<br>| 18.58%<br>| 8.77%<br>|

---

![](img109816_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* | *13.56%* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*December 31, 2022* |
| *Lowest Quarter Return* | *-17.82%* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*June 30, 2022* |
| *Year-to-Date Return* | *13.36%* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;*June 30, 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 | Life of<br> fund  |
| **Fidelity® Water Sustainability Fund** |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp;**Return Before Taxes**  | &nbsp;&nbsp;8.77%  | &nbsp;&nbsp;13.33% A |
| &nbsp;&nbsp;&nbsp;&nbsp;**Return After Taxes on Distributions**  | &nbsp;&nbsp;8.14%  | &nbsp;&nbsp;12.92% A |
| &nbsp;&nbsp;&nbsp;&nbsp;**Return After Taxes on Distributions and Sale of Fund Shares** <br>| &nbsp;&nbsp;5.65%  | &nbsp;&nbsp;10.57% A |
| S&P® Global Water Index<br> **(reflects no deduction for fees, expenses, or taxes)** | &nbsp;&nbsp; <br> 5.51%  | &nbsp;&nbsp; <br> 12.78%  |
| MSCI ACWI (All Country World Index) Index<br> **(reflects no deduction for fees or expenses)** | &nbsp;&nbsp; <br> 17.87%  | &nbsp;&nbsp; <br> 15.49%  |

---

A*From April 16, 2020.*

**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)**

Brian Aronson (Portfolio Manager) has managed the fund since 2023.

**Purchase and Sale of Shares**

You may buy or sell shares through a Fidelity® brokerage or mutual fund account, through a retirement account, or through an investment professional.

You may buy or sell shares in various ways:

**Internet**

**www.fidelity.com**

**Phone**

**Fidelity Automated Service Telephone (FAST®) 1-800-544-5555**

**To reach a Fidelity representative 1-800-544-6666**

**Mail**

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| | |
|:---|:---|
| <br> **Additional Purchases:**<br> **Fidelity Investments**<br> **P.O. Box 770001**<br> **Cincinnati, OH 45277-0003** | <br> **Redemptions:**<br> **Fidelity Investments**<br> **P.O. Box 770001**<br> **Cincinnati, OH 45277-0035** |

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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.

Current regulations allow Fidelity to send a single copy of shareholder documents for Fidelity® funds, such as prospectuses, annual and semi-annual reports, and proxy materials, to certain mutual fund customers whom we believe are members of the same family who share the same address. For certain types of accounts, we will not send multiple copies of these documents to you and members of your family who share the same address. Instead, we will send only a single copy of these documents. This will continue for as long as you are a shareholder, unless you notify us otherwise. If at any time you choose to receive individual copies of any documents, please call 1-800-544-8544. We will begin sending individual copies to you within 30 days of receiving your call.

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.

1.9897483.107 DSW-SUM-0725