# EDGAR Filing Document

**Accession Number:** 0000889512
**File Stem:** 0001193125-25-303458
**Filing Date:** 2025-12
**Character Count:** 4448
**Document Hash:** 293ce6b4736ad324e7e320e1967aaab4
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-303458.hdr.sgml**: 20251201

**ACCESSION NUMBER**: 0001193125-25-303458

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20251201

**DATE AS OF CHANGE**: 20251201

**EFFECTIVENESS DATE**: 20251201

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** LEGG MASON PARTNERS INSTITUTIONAL TRUST
- **CENTRAL INDEX KEY:** 0000889512

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 0831

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-49552
- **FILM NUMBER:** 251538130

**BUSINESS ADDRESS:**
- **STREET 1:** LEGG MASON & CO., LLC
- **STREET 2:** 620 EIGHTH AVENUE
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10018
- **BUSINESS PHONE:** 1-877-721-1926

**MAIL ADDRESS:**
- **STREET 1:** LEGG MASON & CO., LLC
- **STREET 2:** 620 EIGHTH AVENUE
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10018

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** CITIFUNDS INSTITUTIONAL TRUST
- **DATE OF NAME CHANGE:** 19981030

## Series and Classes Contracts Data

### Western Asset Institutional U.S. Treasury Obligations Money Market Fund (Series ID: S000041891)

---

|  |  |  |
|:---|:---|:---|
| Class Name            | Ticker Symbol | Class ID   |
| Institutional Shares  | LUIXX         | C000130074 |
| Administrative Shares | LAOXX         | C000130075 |
| Investor Shares       | LAIXX         | C000130076 |

---

## Series and Classes Contracts Data

### Western Asset Institutional U.S. Treasury Obligations Money Market Fund (Series ID: S000041891)

| Class ID   | Class Name            | Ticker Symbol   |
|:---|:---|:---|
| C000130074 | Institutional Shares  | LUIXX           |
| C000130075 | Administrative Shares | LAOXX           |
| C000130076 | Investor Shares       | LAIXX           |

91067-P1 11/25

![LOGO](g49803g83h05.jpg)

![LOGO](g49803westassetlogo.jpg)

**LEGG MASON PARTNERS INSTITUTIONAL TRUST** 

**SUPPLEMENT DATED DECEMBER 1, 2025** 

**TO THE PROSPECTUS AND** 

**STATEMENT OF ADDITIONAL INFORMATION ("SAI"),** 

**EACH DATED JANUARY 1, 2025, OF** 

**WESTERN ASSET INSTITUTIONAL U.S. TREASURY OBLIGATIONS MONEY MARKET FUND** 

**(THE "FUND")** 

**I.** **Effective January 1, 2026, the following changes are made to the Fund's Prospectus:** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**a)** **The following relaces the fifth paragraph in the section titled "More on the funds' investment strategies, investments and risks—Important information":** 

Institutional U.S. Treasury Obligations Fund intends, under normal circumstances, to invest only in certain eligible reserve assets that payment stablecoin issuers are permitted to maintain under the Guiding and Establishing National Innovation for U.S. Stablecoins ("GENIUS") Act of 2025 and any regulations adopted thereunder. **The fund does not invest in stablecoins.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**b)** **The following replaces the first sentence in the section titled "More on the funds' investment strategies, investments and risks—Maturity":** 

Each fund (other than Institutional U.S. Treasury Obligations Fund) invests in securities that, at the time of purchase, are treated under applicable regulations as having remaining maturities of 397 days or less. Institutional U.S. Treasury Obligations Fund invests in securities that, at the time of purchase, are treated under applicable regulations as having remaining maturities of 93 days or less.

------

**II.** **The following change is made to the Fund's SAI:** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**a)** **The following replaces the first bullet in the section titled "Investment Policies—All Funds":** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **(*For all Funds other than Institutional U.S. Treasury Obligations Money Market Fund*)** The Fund
invests in securities that, at the time of purchase, are treated under applicable regulations as having remaining maturities of 397 days or less.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• **(*For Institutional U.S. Treasury Obligations Money Market Fund*)** The Fund invests in securities
that, at the time of purchase, are treated under applicable regulations as having remaining maturities of 93 days or less.

**Please retain this supplement for future reference.**