# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001145549-25-058041
**Filing Date:** 2025-9
**Character Count:** 14053
**Document Hash:** 91741c7957e8b3454aee6122c904d93a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-058041.hdr.sgml**: 20250908

**ACCESSION NUMBER**: 0001145549-25-058041

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250831

**FILED AS OF DATE**: 20250908

**DATE AS OF CHANGE**: 20250908

**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:** 251299394

**BUSINESS ADDRESS:**
- **STREET 1:** C/O UBS ASSET MANAGEMENT (AMERICAS) LLC
- **STREET 2:** 787 SEVENTH AVENUE
- **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:** 787 SEVENTH AVENUE
- **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 Treasury Preferred Fund (Series ID: S000018677)

| Class ID   | Class Name                         | Ticker Symbol   |
|:---|:---|:---|
| C000051800 | UBS Select Treasury Preferred Fund | STPXX           |

# 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):** 2025-08-31

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

**Name of Series:** UBS Select Treasury Preferred Fund

**LEI of Series:** 549300DXQ8KM8WHPPG39

**EDGAR Series Identifier:** S000018677

**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:** $23802233838.27

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

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $87329608.65

- **Net Assets of Series:** $23714904229.62

- **Number of Shares Outstanding (Series):** 23714774364.7100

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2025-08-01 | $44506064964.22           | $45506064964.22            | 97.7300%                  | 99.9200%                   |
| 2025-08-04 | $45111418371.57           | $46111418371.57            | 97.7600%                  | 99.9300%                   |
| 2025-08-05 | $44647689510.11           | $45647689510.11            | 97.7400%                  | 99.9300%                   |
| 2025-08-06 | $44323799761.11           | $45323799761.11            | 97.7200%                  | 99.9200%                   |
| 2025-08-07 | $43808400315.81           | $44808400315.81            | 97.6900%                  | 99.9200%                   |
| 2025-08-08 | $44424826866.05           | $45424826866.05            | 97.7000%                  | 99.9000%                   |
| 2025-08-11 | $45570100386.94           | $46570100386.94            | 97.7600%                  | 99.9100%                   |
| 2025-08-12 | $46073471200.36           | $47073471200.36            | 97.7900%                  | 99.9100%                   |
| 2025-08-13 | $45806331730.42           | $46806331730.42            | 97.7700%                  | 99.9100%                   |
| 2025-08-14 | $44376609900.64           | $45376609900.64            | 97.7000%                  | 99.9000%                   |
| 2025-08-15 | $45270403747.27           | $46270403747.27            | 97.7200%                  | 99.8800%                   |
| 2025-08-18 | $47434180240.18           | $48434180240.18            | 97.8300%                  | 99.8900%                   |
| 2025-08-19 | $46070800402.84           | $47070800402.84            | 97.7700%                  | 99.8900%                   |
| 2025-08-20 | $45997225047.83           | $46997225047.83            | 97.7600%                  | 99.8900%                   |
| 2025-08-21 | $45452944407.90           | $46452944407.90            | 97.7300%                  | 99.8800%                   |
| 2025-08-22 | $45067044991.15           | $46067044991.15            | 97.6900%                  | 99.8600%                   |
| 2025-08-25 | $46121296945.88           | $47121296945.88            | 97.7500%                  | 99.8700%                   |
| 2025-08-26 | $45694244621.69           | $46694244621.69            | 97.7300%                  | 99.8700%                   |
| 2025-08-27 | $46467484122.50           | $47467484122.50            | 97.7600%                  | 99.8700%                   |
| 2025-08-28 | $45975189077.84           | $46975189077.84            | 97.7400%                  | 99.8600%                   |
| 2025-08-29 | $47107881969.82           | $48107881969.82            | 97.7600%                  | 99.8400%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-08-01 | 4.3800%             |
| 2025-08-04 | 4.3700%             |
| 2025-08-05 | 4.3700%             |
| 2025-08-06 | 4.3700%             |
| 2025-08-07 | 4.3600%             |
| 2025-08-08 | 4.3600%             |
| 2025-08-11 | 4.3600%             |
| 2025-08-12 | 4.3600%             |
| 2025-08-13 | 4.3600%             |
| 2025-08-14 | 4.3600%             |
| 2025-08-15 | 4.3600%             |
| 2025-08-18 | 4.3600%             |
| 2025-08-19 | 4.3500%             |
| 2025-08-20 | 4.3500%             |
| 2025-08-21 | 4.3500%             |
| 2025-08-22 | 4.3500%             |
| 2025-08-25 | 4.3500%             |
| 2025-08-26 | 4.3500%             |
| 2025-08-27 | 4.3500%             |
| 2025-08-28 | 4.3500%             |
| 2025-08-29 | 4.3500%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-08-01 | 1.0002                      |
|  |  |
| 2025-08-04 | 1.0002                      |
|  |  |
| 2025-08-05 | 1.0002                      |
|  |  |
| 2025-08-06 | 1.0002                      |
|  |  |
| 2025-08-07 | 1.0002                      |
|  |  |
| 2025-08-08 | 1.0002                      |
|  |  |
| 2025-08-11 | 1.0002                      |
|  |  |
| 2025-08-12 | 1.0002                      |
|  |  |
| 2025-08-13 | 1.0002                      |
|  |  |
| 2025-08-14 | 1.0002                      |
|  |  |
| 2025-08-15 | 1.0002                      |
|  |  |
| 2025-08-18 | 1.0002                      |
|  |  |
| 2025-08-19 | 1.0002                      |
|  |  |
| 2025-08-20 | 1.0002                      |
|  |  |
| 2025-08-21 | 1.0001                      |
|  |  |
| 2025-08-22 | 1.0002                      |
|  |  |
| 2025-08-25 | 1.0001                      |
|  |  |
| 2025-08-26 | 1.0001                      |
|  |  |
| 2025-08-27 | 1.0002                      |
|  |  |
| 2025-08-28 | 1.0001                      |
|  |  |
| 2025-08-29 | 1.0002                      |
|  |  |

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

### Class: Single Class

- **Minimum Initial Investment:** $50000000.00

- **Net Assets of Class:** $23714904229.62

- **Number of Shares Outstanding:** 23714774364.7100

- **Expense Reimbursement/Waiver:** 844746.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-08-01 | 1.0002          |
|  |  |
| 2025-08-04 | 1.0002          |
|  |  |
| 2025-08-05 | 1.0002          |
|  |  |
| 2025-08-06 | 1.0002          |
|  |  |
| 2025-08-07 | 1.0002          |
|  |  |
| 2025-08-08 | 1.0002          |
|  |  |
| 2025-08-11 | 1.0002          |
|  |  |
| 2025-08-12 | 1.0002          |
|  |  |
| 2025-08-13 | 1.0002          |
|  |  |
| 2025-08-14 | 1.0002          |
|  |  |
| 2025-08-15 | 1.0002          |
|  |  |
| 2025-08-18 | 1.0002          |
|  |  |
| 2025-08-19 | 1.0002          |
|  |  |
| 2025-08-20 | 1.0002          |
|  |  |
| 2025-08-21 | 1.0001          |
|  |  |
| 2025-08-22 | 1.0002          |
|  |  |
| 2025-08-25 | 1.0001          |
|  |  |
| 2025-08-26 | 1.0001          |
|  |  |
| 2025-08-27 | 1.0002          |
|  |  |
| 2025-08-28 | 1.0001          |
|  |  |
| 2025-08-29 | 1.0002          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-08-01 | $854542782.79             | $481715865.92           |
| 2025-08-04 | $408850003.01             | $98563766.97            |
| 2025-08-05 | $705536122.45             | $236535707.47           |
| 2025-08-06 | $249577186.41             | $674618364.35           |
| 2025-08-07 | $324185190.96             | $257934011.29           |
| 2025-08-08 | $271519179.02             | $176536831.10           |
| 2025-08-11 | $461222031.14             | $202046214.64           |
| 2025-08-12 | $517834774.46             | $608195096.15           |
| 2025-08-13 | $297252630.32             | $365977150.58           |
| 2025-08-14 | $522197910.24             | $450293396.29           |
| 2025-08-15 | $1104727087.90            | $390764436.33           |
| 2025-08-18 | $866364104.62             | $421566038.68           |
| 2025-08-19 | $252737356.65             | $369703308.48           |
| 2025-08-20 | $250806032.96             | $502880634.69           |
| 2025-08-21 | $270751702.26             | $425411984.61           |
| 2025-08-22 | $487466319.68             | $1398874941.37          |
| 2025-08-25 | $1191173591.83            | $735495162.93           |
| 2025-08-26 | $331731330.26             | $399068485.43           |
| 2025-08-27 | $277080081.30             | $951726264.17           |
| 2025-08-28 | $341172908.01             | $452151826.70           |
| 2025-08-29 | $912548769.20             | $646511363.33           |

**Total Gross Subscriptions (Month):** $10899277095.47

**Total Gross Redemptions (Month):** $10246570851.48

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-08-01 | 4.2400%           |
| 2025-08-04 | 4.2300%           |
| 2025-08-05 | 4.2300%           |
| 2025-08-06 | 4.2300%           |
| 2025-08-07 | 4.2200%           |
| 2025-08-08 | 4.2200%           |
| 2025-08-11 | 4.2200%           |
| 2025-08-12 | 4.2200%           |
| 2025-08-13 | 4.2200%           |
| 2025-08-14 | 4.2200%           |
| 2025-08-15 | 4.2200%           |
| 2025-08-18 | 4.2200%           |
| 2025-08-19 | 4.2100%           |
| 2025-08-20 | 4.2100%           |
| 2025-08-21 | 4.2100%           |
| 2025-08-22 | 4.2100%           |
| 2025-08-25 | 4.2100%           |
| 2025-08-26 | 4.2100%           |
| 2025-08-27 | 4.2100%           |
| 2025-08-28 | 4.2200%           |
| 2025-08-29 | 4.2100%           |

**Beneficial/Record Owner Categories**
| Category                                                                    | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| State or municipal government entity (excluding governmental pension plans) |  | 13.1600%         | 0.0000%              |
| Other                                                                       | IND FID AS EXEC  | 6.8300%          | 0.0000%              |

## Part C: Schedule of Portfolio Securities

### Security 1: Treasury Master Fund

- **C.1 - Title:** Treasury Master Fund
- **C.6 - Investment Category:** Investment Company
- **Identifiers:** C.3 - CUSIP: 81699K911, C.3 - LEI: 549300XQ6V293JKF0677, C.5 - Other ID: 81699K911
- **C.18 - Value (incl. sponsor support):** $23802233838.27
- **C.18.a - Value (excl. sponsor support):** $23802233838.27
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-09-02
- **C.12 - Maturity Date (WAL):** 2025-09-02
- **C.13 - Final Legal Maturity Date:** 2025-09-02
- **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:** 2025-09-08

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

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

**Title of Signing Officer:** Vice President