# EDGAR Filing Document

**Accession Number:** 0000356173
**File Stem:** 0000356173-25-000047
**Filing Date:** 2025-9
**Character Count:** 17625
**Document Hash:** 6531271373f75f67227c15af9384b190
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000356173-25-000047.hdr.sgml**: 20250922

**ACCESSION NUMBER**: 0000356173-25-000047

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250922

**DATE AS OF CHANGE**: 20250922

**EFFECTIVENESS DATE**: 20250922

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Fidelity Colchester Street Trust
- **CENTRAL INDEX KEY:** 0000356173

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0331

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-74808
- **FILM NUMBER:** 251329220

**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:** COLCHESTER STREET TRUST
- **DATE OF NAME CHANGE:** 19980324

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FIDELITY INSTITUTIONAL CASH PORTFOLIOS
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CASH INVESTMENT FUND
- **DATE OF NAME CHANGE:** 19850414

## Series and Classes Contracts Data

### Treasury Only Portfolio (Series ID: S000004818)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Class I             | FSIXX         | C000013037 |
| Class II            | FOXXX         | C000013074 |
| Class III           | FOIXX         | C000013075 |
| Select Class        | FTYXX         | C000013076 |
| Class IV            | FOPXX         | C000056567 |
| Institutional Class | FRSXX         | C000141702 |

---

### Treasury Portfolio (Series ID: S000004819)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Class I             | FISXX         | C000013038 |
| Class II            | FCEXX         | C000013077 |
| Class III           | FCSXX         | C000013078 |
| Select Class        | FTUXX         | C000013079 |
| Class IV            | FTVXX         | C000056568 |
| Institutional Class | FRBXX         | C000141703 |

---

### Government Portfolio (Series ID: S000004820)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Class I             | FIGXX         | C000013039 |
| Class II            | FCVXX         | C000013080 |
| Class III           | FCGXX         | C000013081 |
| Select Class        | FGEXX         | C000013082 |
| Institutional Class | FRGXX         | C000141704 |

---

### Money Market Portfolio (Series ID: S000004822)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Class I             | FMPXX         | C000013041 |
| Class II            | FCIXX         | C000013086 |
| Class III           | FCOXX         | C000013087 |
| Select Class        | FMYXX         | C000013088 |
| Institutional Class | FNSXX         | C000056571 |

---

### Tax-Exempt Portfolio (Series ID: S000004823)

---

|  |  |  |
|:---|:---|:---|
| Class Name   | Ticker Symbol | Class ID   |
| Class I      | FTCXX         | C000013042 |
| Class II     | FEXXX         | C000013089 |
| Class III    | FETXX         | C000013090 |
| Select Class | FSXXX         | C000013091 |

---

## Series and Classes Contracts Data

### Treasury Only Portfolio (Series ID: S000004818)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000013037 | Class I             | FSIXX           |
| C000013074 | Class II            | FOXXX           |
| C000013075 | Class III           | FOIXX           |
| C000013076 | Select Class        | FTYXX           |
| C000056567 | Class IV            | FOPXX           |
| C000141702 | Institutional Class | FRSXX           |

### Treasury Portfolio (Series ID: S000004819)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000013038 | Class I             | FISXX           |
| C000013077 | Class II            | FCEXX           |
| C000013078 | Class III           | FCSXX           |
| C000013079 | Select Class        | FTUXX           |
| C000056568 | Class IV            | FTVXX           |
| C000141703 | Institutional Class | FRBXX           |

### Government Portfolio (Series ID: S000004820)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000013039 | Class I             | FIGXX           |
| C000013080 | Class II            | FCVXX           |
| C000013081 | Class III           | FCGXX           |
| C000013082 | Select Class        | FGEXX           |
| C000141704 | Institutional Class | FRGXX           |

### Money Market Portfolio (Series ID: S000004822)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000013041 | Class I             | FMPXX           |
| C000013086 | Class II            | FCIXX           |
| C000013087 | Class III           | FCOXX           |
| C000013088 | Select Class        | FMYXX           |
| C000056571 | Institutional Class | FNSXX           |

### Tax-Exempt Portfolio (Series ID: S000004823)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000013042 | Class I      | FTCXX           |
| C000013089 | Class II     | FEXXX           |
| C000013090 | Class III    | FETXX           |
| C000013091 | Select Class | FSXXX           |

**Supplement to the**

**Fidelity® Investments Money Market Funds**

**Class II**

**May 30, 2025**

**Prospectus**

The following information replaces similar information for Treasury Only Portfolio found in the "Investment Details" section under the "Principal Investment Strategies" heading.

The Adviser normally invests at least 99.5% of the fund's total assets in cash and U.S. Treasury securities. Under normal circumstances, the Adviser does not enter into repurchase agreements or reverse repurchase agreements for the fund. The Adviser normally invests the fund's assets in securities whose interest is specifically exempt from state and local income taxes under federal law; such interest is not exempt from federal income tax.

The following information replaces similar information found in the "Investment Details" section under the "Principal Investment Risks" heading.

In response to market, economic, political, or other conditions, a fund may temporarily use a different investment strategy (including leaving a significant portion of the fund's assets uninvested or, in the case of Treasury Only Portfolio, investing in repurchase agreements collateralized by U.S. Treasury obligations) for defensive purposes. Uninvested assets do not earn income for a fund, which may have a significant negative impact on the fund's yield and may prevent the fund from achieving its investment objective. In addition, different factors could affect a fund's performance, and Tax-Exempt Portfolio could distribute income subject to federal income tax. The addition of repurchase agreements could cause a portion of the income from Treasury Only Portfolio to be subject to state and local income taxes.

IMMII-PSTK-0925-136 1.480139.136 September 22, 2025

**Supplement to the**

**Fidelity® Investments Money Market Funds**

**Class III May 30, 2025**

**Prospectus**

The following information replaces similar information for Treasury Only Portfolio found in the "Investment Details" section under the "Principal Investment Strategies" heading.

The Adviser normally invests at least 99.5% of the fund's total assets in cash and U.S. Treasury securities. Under normal circumstances, the Adviser does not enter into repurchase agreements or reverse repurchase agreements for the fund. The Adviser normally invests the fund's assets in securities whose interest is specifically exempt from state and local income taxes under federal law; such interest is not exempt from federal income tax.

The following information replaces similar information found in the "Investment Details" section under the "Principal Investment Risks" heading.

In response to market, economic, political, or other conditions, a fund may temporarily use a different investment strategy (including leaving a significant portion of the fund's assets uninvested or, in the case of Treasury Only Portfolio, investing in repurchase agreements collateralized by U.S. Treasury obligations) for defensive purposes. Uninvested assets do not earn income for a fund, which may have a significant negative impact on the fund's yield and may prevent the fund from achieving its investment objective. In addition, different factors could affect a fund's performance, and Tax-Exempt Portfolio could distribute income subject to federal income tax. The addition of repurchase agreements could cause a portion of the income from Treasury Only Portfolio to be subject to state and local income taxes.

IMMIII-PSTK-0925-136 1.480140.136 September 22, 2025

**Supplement to the**

**Fidelity® Investments Money Market Funds**

**Class IV**

**May 30, 2025**

**Prospectus**

The following information replaces similar information for Treasury Only Portfolio found in the "Investment Details" section under the "Principal Investment Strategies" heading.

The Adviser normally invests at least 99.5% of the fund's total assets in cash and U.S. Treasury securities. Under normal circumstances, the Adviser does not enter into repurchase agreements or reverse repurchase agreements for the fund. The Adviser normally invests the fund's assets in securities whose interest is specifically exempt from state and local income taxes under federal law; such interest is not exempt from federal income tax.

The following information replaces similar information found in the "Investment Details" section under the "Principal Investment Risks" heading.

In response to market, economic, political, or other conditions, a fund may temporarily use a different investment strategy (including leaving a significant portion of the fund's assets uninvested or, in the case of Treasury Only Portfolio, investing in repurchase agreements collateralized by U.S. Treasury obligations) for defensive purposes. Uninvested assets do not earn income for a fund, which may have a significant negative impact on the fund's yield and may prevent the fund from achieving its investment objective. In addition, different factors could affect a fund's performance, and Tax-Exempt Portfolio could distribute income subject to federal income tax. The addition of repurchase agreements could cause a portion of the income from Treasury Only Portfolio to be subject to state and local income taxes.

TRO-PSTK-0925-123 1.864395.123 September 22, 2025

**Supplement to the**

**Fidelity® Investments Money Market Funds**

**Institutional Class**

**May 30, 2025**

**Prospectus**

The following information replaces similar information for Treasury Only Portfolio found in the "Investment Details" section under the "Principal Investment Strategies" heading.

The Adviser normally invests at least 99.5% of the fund's total assets in cash and U.S. Treasury securities. Under normal circumstances, the Adviser does not enter into repurchase agreements or reverse repurchase agreements for the fund. The Adviser normally invests the fund's assets in securities whose interest is specifically exempt from state and local income taxes under federal law; such interest is not exempt from federal income tax.

The following information replaces similar information found in the "Investment Details" section under the "Principal Investment Risks" heading.

In response to market, economic, political, or other conditions, a fund may temporarily use a different investment strategy (including leaving a significant portion of the fund's assets uninvested or, in the case of Treasury Only Portfolio, investing in repurchase agreements collateralized by U.S. Treasury obligations) for defensive purposes. Uninvested assets do not earn income for a fund, which may have a significant negative impact on the fund's yield and may prevent the fund from achieving its investment objective. In addition, different factors could affect a fund's performance, and Tax-Exempt Portfolio could distribute income subject to federal income tax. The addition of repurchase agreements could cause a portion of the income from Treasury Only Portfolio to be subject to state and local income taxes.

PMM-PSTK-0925-120 1.880937.120 September 22, 2025

**Supplement to the**

**Fidelity® Investments Money Market Funds**

**Select Class**

**May 30, 2025**

**Prospectus**

The following information replaces similar information for Treasury Only Portfolio found in the "Investment Details" section under the "Principal Investment Strategies" heading.

The Adviser normally invests at least 99.5% of the fund's total assets in cash and U.S. Treasury securities. Under normal circumstances, the Adviser does not enter into repurchase agreements or reverse repurchase agreements for the fund. The Adviser normally invests the fund's assets in securities whose interest is specifically exempt from state and local income taxes under federal law; such interest is not exempt from federal income tax.

The following information replaces similar information found in the "Investment Details" section under the "Principal Investment Risks" heading.

In response to market, economic, political, or other conditions, a fund may temporarily use a different investment strategy (including leaving a significant portion of the fund's assets uninvested or, in the case of Treasury Only Portfolio, investing in repurchase agreements collateralized by U.S. Treasury obligations) for defensive purposes. Uninvested assets do not earn income for a fund, which may have a significant negative impact on the fund's yield and may prevent the fund from achieving its investment objective. In addition, different factors could affect a fund's performance, and Tax-Exempt Portfolio could distribute income subject to federal income tax. The addition of repurchase agreements could cause a portion of the income from Treasury Only Portfolio to be subject to state and local income taxes.

IMMSC-PSTK-0925-127 1.778424.127 September 22, 2025

**Supplement to the**

**Government Portfolio, Money Market Portfolio, Tax-Exempt Portfolio, Treasury Only Portfolio, and Treasury Portfolio**

**Class I, Class II, Class III, Class IV, Select Class, and Institutional Class**

**May 30, 2025**

**STATEMENT OF ADDITIONAL INFORMATION**

*The following information replaces similar information found in the "Investment Policies and Limitations" section.*

**Loans**

*For Tax-Exempt Portfolio and Treasury Only Portfolio:*

The fund does not currently intend to engage in repurchase agreements or make loans, but this limitation does not apply to purchases of debt securities.

For purposes of Treasury Only Portfolio's temporary defensive policy, the fund reserves the right to invest in repurchase agreements collateralized by U.S. Treasury obligations.

*The following information replaces similar information found in the "Investment Policies and Limitations" section.*

**<u>Temporary Defensive Policies.</u>** Each of Government Portfolio, Money Market Portfolio, Tax-Exempt Portfolio, Treasury Only Portfolio, and Treasury Portfolio reserves the right to hold a substantial amount of uninvested cash for temporary, defensive purposes. Further, Treasury Only Portfolio reserves the right to invest in repurchase agreements collateralized by U.S. Treasury obligations for temporary, defensive purposes.

In addition, each of Government Portfolio, Money Market Portfolio, Tax-Exempt Portfolio, Treasury Only Portfolio, and Treasury Portfolio reserves the right to invest more than normally permitted in federally taxable obligations for temporary, defensive purposes.

IMM-SSTK-0925-126-1.480584.126 September 22, 2025

**Supplement to the Fidelity® Investments Money Market Funds**

**Class I May 30, 2025 Prospectus**

The following information replaces similar information for Treasury Only Portfolio found in the "Investment Details" section under the "Principal Investment Strategies" heading.

The Adviser normally invests at least 99.5% of the fund's total assets in cash and U.S. Treasury securities. Under normal circumstances, the Adviser does not enter into repurchase agreements or reverse repurchase agreements for the fund. The Adviser normally invests the fund's assets in securities whose interest is specifically exempt from state and local income taxes under federal law; such interest is not exempt from federal income tax.

The following information replaces similar information found in the "Investment Details" section under the "Principal Investment Risks" heading.

In response to market, economic, political, or other conditions, a fund may temporarily use a different investment strategy (including leaving a significant portion of the fund's assets uninvested or, in the case of Treasury Only Portfolio, investing in repurchase agreements collateralized by U.S. Treasury obligations) for defensive purposes. Uninvested assets do not earn income for a fund, which may have a significant negative impact on the fund's yield and may prevent the fund from achieving its investment objective. In addition, different factors could affect a fund's performance, and Tax-Exempt Portfolio could distribute income subject to federal income tax. The addition of repurchase agreements could cause a portion of the income from Treasury Only Portfolio to be subject to state and local income taxes.

IMMI-PSTK-0925-139 1.480138.139 September 22, 2025