# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-26-010505
**Filing Date:** 2026-2
**Character Count:** 13292
**Document Hash:** 016b0684e004c4748b2ebea39dbd5797
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-010505.hdr.sgml**: 20260206

**ACCESSION NUMBER**: 0001410368-26-010505

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260131

**FILED AS OF DATE**: 20260206

**DATE AS OF CHANGE**: 20260206

**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:** N-MFP3
- **SEC ACT:** 1940 Act
- **SEC FILE NUMBER:** 811-08767
- **FILM NUMBER:** 26607345

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

# Form N-MFP3: Monthly Schedule of Portfolio Holdings

## N-MFP: Filer Information
**Submission Type:** N-MFP3
**CIK:** 0001060517

### General Information

**Report for (YYYY-MM-DD):** 2026-01-31

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

**Name of Series:** UBS Select 100% US Treasury Institutional Fund

**LEI of Series:** 529900KWG787B4G5P791

**EDGAR Series Identifier:** S000084282

**Total number of share classes in the series:** 1

**Is this the fund's final filing on Form N-MFP?:** No

**Has the fund acquired or merged with another fund?:** No

## Part A: Series-Level Information about the Fund

### Service Providers
| Role                          | Details                                                      | File/CIK Number   |
|:---|:---|:---|
| Investment Adviser            | UBS ASSET MANAGEMENT (AMERICAS) LLC                          | 801-34910         |
| Independent Public Accountant | Ernst & Young  LLP<br>City: New York<br>State: NY            |  |
| Administrator                 | UBS ASSET MANAGEMENT (AMERICAS) LLC                          |  |
| Transfer Agent                | BNY Mellon Investment Servicing (US) Inc.<br>CIK: 0000849542 | 084-01761         |

### Fund Characteristics & Assets

- **Securities Act File Number:** 333-52965

- **Is this a Feeder Fund?:** Yes

- **Is this a Master Fund?:** No

- **Is this series for insurance company separate accounts?:** No

- **Money Market Fund Category:** Government

- **Is this a Retail Money Market Fund?:** No

- **Is this a Government Money Market Fund?:** Yes

- **WAM:** 1 days

- **WAL:** 1 days

- **Total Value of Portfolio Securities:** $7774571449.09

- **Amortized Cost of Portfolio Securities:** $0.00

- **Cash:** $0.00

- **Total Other Assets:** $59390.70

- **Total Liabilities:** $25430932.93

- **Net Assets of Series:** $7749199906.86

- **Number of Shares Outstanding (Series):** 7749046314.6000

- **Does the fund seek to maintain a stable price per share?:** Yes

- **Stable Price Per Share:** $1.00

- **Is cash management vehicle an affiliated fund?:** No

- **Does the fund apply liquidity fees?:** No

### Daily & Weekly Liquid Assets
| Date       | Daily Liquid Assets ($)   | Weekly Liquid Assets ($)   | Daily Liquid Assets (%)   | Weekly Liquid Assets (%)   |
|:---|:---|:---|:---|:---|
| 2026-01-02 | $17009605893.01           | $17009605893.01            | 99.8800%                  | 99.8800%                   |
| 2026-01-05 | $17243806274.68           | $17243806274.68            | 99.8800%                  | 99.8800%                   |
| 2026-01-06 | $17042264868.74           | $17042264868.74            | 99.8800%                  | 99.8800%                   |
| 2026-01-07 | $17169045624.64           | $17169045624.64            | 99.8900%                  | 99.8900%                   |
| 2026-01-08 | $17161306762.89           | $17161306762.89            | 99.8900%                  | 99.8900%                   |
| 2026-01-09 | $17274766549.89           | $17274766549.89            | 99.8800%                  | 99.8800%                   |
| 2026-01-12 | $17617354880.51           | $17617354880.51            | 99.8800%                  | 99.8800%                   |
| 2026-01-13 | $17108097656.57           | $17108097656.57            | 99.8800%                  | 99.8800%                   |
| 2026-01-14 | $17225499515.76           | $17225499515.76            | 99.8800%                  | 99.8800%                   |
| 2026-01-15 | $17161614954.01           | $17161614954.01            | 99.8800%                  | 99.8800%                   |
| 2026-01-16 | $17257226484.14           | $17257226484.14            | 99.8800%                  | 99.8800%                   |
| 2026-01-20 | $17209566844.12           | $17209566844.12            | 99.8900%                  | 99.8900%                   |
| 2026-01-21 | $17484514691.81           | $17484514691.81            | 99.8900%                  | 99.8900%                   |
| 2026-01-22 | $17375463914.26           | $17375463914.26            | 99.8800%                  | 99.8800%                   |
| 2026-01-23 | $17415361104.11           | $17415361104.11            | 99.8800%                  | 99.8800%                   |
| 2026-01-26 | $17962838131.85           | $17962838131.85            | 99.8900%                  | 99.8900%                   |
| 2026-01-27 | $17313555213.48           | $17313555213.48            | 99.8900%                  | 99.8900%                   |
| 2026-01-28 | $17443506485.80           | $17443506485.80            | 99.8900%                  | 99.8900%                   |
| 2026-01-29 | $17809804638.49           | $17809804638.49            | 99.8900%                  | 99.8900%                   |
| 2026-01-30 | $17824943973.37           | $17824943973.37            | 99.8900%                  | 99.8900%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2026-01-02 | 3.7900%             |
| 2026-01-05 | 3.7900%             |
| 2026-01-06 | 3.7800%             |
| 2026-01-07 | 3.7800%             |
| 2026-01-08 | 3.7700%             |
| 2026-01-09 | 3.7600%             |
| 2026-01-12 | 3.7500%             |
| 2026-01-13 | 3.7500%             |
| 2026-01-14 | 3.7500%             |
| 2026-01-15 | 3.7500%             |
| 2026-01-16 | 3.7400%             |
| 2026-01-20 | 3.7400%             |
| 2026-01-21 | 3.7300%             |
| 2026-01-22 | 3.7300%             |
| 2026-01-23 | 3.7300%             |
| 2026-01-26 | 3.7300%             |
| 2026-01-27 | 3.7200%             |
| 2026-01-28 | 3.7200%             |
| 2026-01-29 | 3.7200%             |
| 2026-01-30 | 3.7100%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2026-01-02 | 1.0002                      |
|  |  |
| 2026-01-05 | 1.0002                      |
|  |  |
| 2026-01-06 | 1.0002                      |
|  |  |
| 2026-01-07 | 1.0002                      |
|  |  |
| 2026-01-08 | 1.0002                      |
|  |  |
| 2026-01-09 | 1.0002                      |
|  |  |
| 2026-01-12 | 1.0002                      |
|  |  |
| 2026-01-13 | 1.0002                      |
|  |  |
| 2026-01-14 | 1.0001                      |
|  |  |
| 2026-01-15 | 1.0001                      |
|  |  |
| 2026-01-16 | 1.0001                      |
|  |  |
| 2026-01-20 | 1.0001                      |
|  |  |
| 2026-01-21 | 1.0001                      |
|  |  |
| 2026-01-22 | 1.0001                      |
|  |  |
| 2026-01-23 | 1.0001                      |
|  |  |
| 2026-01-26 | 1.0001                      |
|  |  |
| 2026-01-27 | 1.0001                      |
|  |  |
| 2026-01-28 | 1.0001                      |
|  |  |
| 2026-01-29 | 1.0001                      |
|  |  |
| 2026-01-30 | 1.0001                      |
|  |  |

## Part B: Class-Level Information about the Fund

### Class: Single Class

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $7749199906.86

- **Number of Shares Outstanding:** 7749046314.6000

- **Expense Reimbursement/Waiver:** 35979.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-01-02 | 1.0002          |
|  |  |
| 2026-01-05 | 1.0002          |
|  |  |
| 2026-01-06 | 1.0002          |
|  |  |
| 2026-01-07 | 1.0002          |
|  |  |
| 2026-01-08 | 1.0002          |
|  |  |
| 2026-01-09 | 1.0002          |
|  |  |
| 2026-01-12 | 1.0002          |
|  |  |
| 2026-01-13 | 1.0002          |
|  |  |
| 2026-01-14 | 1.0001          |
|  |  |
| 2026-01-15 | 1.0001          |
|  |  |
| 2026-01-16 | 1.0001          |
|  |  |
| 2026-01-20 | 1.0001          |
|  |  |
| 2026-01-21 | 1.0001          |
|  |  |
| 2026-01-22 | 1.0001          |
|  |  |
| 2026-01-23 | 1.0001          |
|  |  |
| 2026-01-26 | 1.0001          |
|  |  |
| 2026-01-27 | 1.0001          |
|  |  |
| 2026-01-28 | 1.0001          |
|  |  |
| 2026-01-29 | 1.0001          |
|  |  |
| 2026-01-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-01-02 | $102864137.25             | $40926547.25            |
| 2026-01-05 | $67417810.34              | $47231247.68            |
| 2026-01-06 | $73569080.96              | $70828030.18            |
| 2026-01-07 | $56695250.33              | $53366323.73            |
| 2026-01-08 | $69758195.17              | $48772514.79            |
| 2026-01-09 | $162544659.60             | $60090683.63            |
| 2026-01-12 | $90108670.34              | $57980933.19            |
| 2026-01-13 | $43986497.97              | $106005462.13           |
| 2026-01-14 | $84349971.97              | $86608289.93            |
| 2026-01-15 | $97676282.86              | $54977084.39            |
| 2026-01-16 | $140413237.48             | $48859042.86            |
| 2026-01-20 | $43773068.32              | $92357899.45            |
| 2026-01-21 | $70661418.21              | $72723986.71            |
| 2026-01-22 | $54724166.50              | $42257219.74            |
| 2026-01-23 | $88493255.93              | $58475381.31            |
| 2026-01-26 | $46315165.20              | $129566235.02           |
| 2026-01-27 | $63253574.65              | $77389595.91            |
| 2026-01-28 | $45975175.61              | $79216202.69            |
| 2026-01-29 | $69804953.73              | $43473362.20            |
| 2026-01-30 | $90316563.87              | $43133421.09            |

**Total Gross Subscriptions (Month):** $1562701136.29

**Total Gross Redemptions (Month):** $1314239463.88

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-01-02 | 3.6100%           |
| 2026-01-05 | 3.6100%           |
| 2026-01-06 | 3.6000%           |
| 2026-01-07 | 3.6000%           |
| 2026-01-08 | 3.5900%           |
| 2026-01-09 | 3.5800%           |
| 2026-01-12 | 3.5800%           |
| 2026-01-13 | 3.5700%           |
| 2026-01-14 | 3.5700%           |
| 2026-01-15 | 3.5700%           |
| 2026-01-16 | 3.5600%           |
| 2026-01-20 | 3.5600%           |
| 2026-01-21 | 3.5500%           |
| 2026-01-22 | 3.5500%           |
| 2026-01-23 | 3.5500%           |
| 2026-01-26 | 3.5500%           |
| 2026-01-27 | 3.5400%           |
| 2026-01-28 | 3.5400%           |
| 2026-01-29 | 3.5400%           |
| 2026-01-30 | 3.5300%           |

## Part C: Schedule of Portfolio Securities

### Security 1: 100 [percent symbol] US Treasury Master Fund

- **C.1 - Title:** 100 [percent symbol] US Treasury Master Fund
- **C.6 - Investment Category:** Investment Company
- **Identifiers:** C.3 - CUSIP: 902656883, C.3 - LEI: 5299000M97HC3J8TJ387
- **C.18 - Value (incl. sponsor support):** $7774571449.09
- **C.18.a - Value (excl. sponsor support):** $7774571449.09
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2026-02-02
- **C.12 - Maturity Date (WAL):** 2026-02-02
- **C.13 - Final Legal Maturity Date:** 2026-02-02
- **Characteristics:** C.9 Eligible Security? Yes, C.14 Has Demand Feature? No, C.15 Has Guarantee? No, C.16 Has Enhancement? No, C.22 Is an Illiquid Security? No, C.20 Is a Daily Liquid Asset? Yes, C.21 Is a Weekly Liquid Asset? Yes, C.23 Categorized at Level 3? No

## N-MFP: Signatures

**Registrant:** UBS Series Funds

**Date:** 2026-02-06

**By:** /s/Rose Ann Bubloski

**Name of Signing Officer:** Rose Ann Bubloski

**Title of Signing Officer:** Vice President