# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001193125-26-022759
**Filing Date:** 2026-1
**Character Count:** 2873
**Document Hash:** de262bda68ded5aabd610eae3c3cbabb
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-022759.hdr.sgml**: 20260126

**ACCESSION NUMBER**: 0001193125-26-022759

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260126

**DATE AS OF CHANGE**: 20260126

**EFFECTIVENESS DATE**: 20260126

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** UBS Series Funds
- **CENTRAL INDEX KEY:** 0001060517

**ORGANIZATION NAME:**
- **EIN:** 134010447
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0430

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-52965
- **FILM NUMBER:** 26561249

**BUSINESS ADDRESS:**
- **STREET 1:** C/O UBS ASSET MANAGEMENT (AMERICAS) LLC
- **STREET 2:** 1285 AVENUE OF THE AMERICAS
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
- **BUSINESS PHONE:** 212-821-3000

**MAIL ADDRESS:**
- **STREET 1:** C/O UBS ASSET MANAGEMENT (AMERICAS) LLC
- **STREET 2:** 1285 AVENUE OF THE AMERICAS
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** UBS MONEY SERIES
- **DATE OF NAME CHANGE:** 20020716

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** BRINSON MONEY SERIES
- **DATE OF NAME CHANGE:** 20010625

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MITCHELL HUTCHINS LIR MONEY SERIES
- **DATE OF NAME CHANGE:** 19990730

## Series and Classes Contracts Data

### UBS Select 100% US Treasury Institutional Fund (Series ID: S000084282)

---

|  |  |  |
|:---|:---|:---|
| Class Name                                     | Ticker Symbol | Class ID   |
| UBS Select 100% US Treasury Institutional Fund | SIOXX         | C000248579 |

---

## Series and Classes Contracts Data

### UBS Select 100% US Treasury Institutional Fund (Series ID: S000084282)

| Class ID   | Class Name                                     | Ticker Symbol   |
|:---|:---|:---|
| C000248579 | UBS Select 100% US Treasury Institutional Fund | SIOXX           |

![LOGO](g47888g83w83.jpg)

## UBS Series Funds
January 26, 2026

**Supplement to the prospectus dated August 28, 2025.** 

**Includes:** 

• UBS Select 100% US Treasury Institutional Fund

Dear Investor,

The purpose of this supplement is to update certain information for UBS Select 100% US Treasury Institutional Fund (the "fund"), a series of UBS Series Funds (the "Trust").

The Trust's Board of Trustees has redesignated existing shares of the fund as "Institutional Shares" because of the creation of another share class of the fund, Token-Enabled Shares, which are offered by a separate prospectus that is also dated January 26, 2026.

**Effective immediately, the fund's prospectus dated August 28, 2025, is hereby revised as follows:** 

All references to "shares" of the fund are hereby replaced with "Institutional Shares."

**PLEASE BE SURE TO RETAIN THIS IMPORTANT INFORMATION FOR FUTURE REFERENCE.** 

ZS-1291