# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001145549-25-050830
**Filing Date:** 2025-8
**Character Count:** 18166
**Document Hash:** bf176dc60ce21a782e707c632dc04016
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-050830.hdr.sgml**: 20250807

**ACCESSION NUMBER**: 0001145549-25-050830

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250731

**FILED AS OF DATE**: 20250807

**DATE AS OF CHANGE**: 20250807

**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:** 251193131

**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 100% US Treasury Preferred Fund (Series ID: S000084283)

| Class ID   | Class Name   | Ticker Symbol   |
|:---|:---|:---|
| C000248580 | Class P      | STAXX           |
| C000250059 | Class T      | SOPXX           |

# 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):** 2025-07-31

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

**Name of Series:** 100% US Treasury Preferred Fund

**LEI of Series:** 529900FTKZBAKZ4ON106

**EDGAR Series Identifier:** S000084283

**Total number of share classes in the series:** 2

**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:** $5634413323.76

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

- **Cash:** $0.00

- **Total Other Assets:** $102749.20

- **Total Liabilities:** $20174319.09

- **Net Assets of Series:** $5614341753.87

- **Number of Shares Outstanding (Series):** 5614290194.6900

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2025-07-01 | $11518048290.58           | $11518048290.58            | 99.8200%                  | 99.8200%                   |
| 2025-07-02 | $12277557714.09           | $12277557714.09            | 99.8300%                  | 99.8300%                   |
| 2025-07-03 | $11639037464.50           | $11639037464.50            | 99.8100%                  | 99.8100%                   |
| 2025-07-07 | $12807372077.04           | $12807372077.04            | 99.8300%                  | 99.8300%                   |
| 2025-07-08 | $12040597575.94           | $12040597575.94            | 99.8200%                  | 99.8200%                   |
| 2025-07-09 | $12729379901.08           | $12729379901.08            | 99.8200%                  | 99.8200%                   |
| 2025-07-10 | $12507682738.30           | $12507682738.30            | 99.8200%                  | 99.8200%                   |
| 2025-07-11 | $12591985658.40           | $12591985658.40            | 99.8100%                  | 99.8100%                   |
| 2025-07-14 | $13284506619.95           | $13284506619.95            | 99.8200%                  | 99.8200%                   |
| 2025-07-15 | $12550349109.48           | $12550349109.48            | 99.8200%                  | 99.8200%                   |
| 2025-07-16 | $13225691083.80           | $13225691083.80            | 99.8200%                  | 99.8200%                   |
| 2025-07-17 | $12895449392.80           | $12895449392.80            | 99.8200%                  | 99.8200%                   |
| 2025-07-18 | $12906319611.97           | $12906319611.97            | 99.8100%                  | 99.8100%                   |
| 2025-07-21 | $13645059130.40           | $13645059130.40            | 99.8200%                  | 99.8200%                   |
| 2025-07-22 | $12798716661.10           | $12798716661.10            | 99.8000%                  | 99.8000%                   |
| 2025-07-23 | $13365838597.63           | $13365838597.63            | 99.8100%                  | 99.8100%                   |
| 2025-07-24 | $12751876245.32           | $12751876245.32            | 99.8000%                  | 99.8000%                   |
| 2025-07-25 | $12731115661.84           | $12731115661.84            | 99.7900%                  | 99.7900%                   |
| 2025-07-28 | $13918005094.18           | $13918005094.18            | 99.8100%                  | 99.8100%                   |
| 2025-07-29 | $12604453629.78           | $12604453629.78            | 99.7800%                  | 99.7800%                   |
| 2025-07-30 | $13589096686.89           | $13589096686.89            | 99.8000%                  | 99.8000%                   |
| 2025-07-31 | $12481870276.54           | $12481870276.54            | 99.9500%                  | 99.9500%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-07-01 | 4.2800%             |
| 2025-07-02 | 4.2800%             |
| 2025-07-03 | 4.2700%             |
| 2025-07-07 | 4.2700%             |
| 2025-07-08 | 4.2700%             |
| 2025-07-09 | 4.2700%             |
| 2025-07-10 | 4.2800%             |
| 2025-07-11 | 4.2900%             |
| 2025-07-14 | 4.2900%             |
| 2025-07-15 | 4.2900%             |
| 2025-07-16 | 4.2900%             |
| 2025-07-17 | 4.3000%             |
| 2025-07-18 | 4.3000%             |
| 2025-07-21 | 4.3100%             |
| 2025-07-22 | 4.3100%             |
| 2025-07-23 | 4.3100%             |
| 2025-07-24 | 4.3100%             |
| 2025-07-25 | 4.3200%             |
| 2025-07-28 | 4.3200%             |
| 2025-07-29 | 4.3200%             |
| 2025-07-30 | 4.3200%             |
| 2025-07-31 | 4.3300%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-07-01 | 1.0000                      |
|  |  |
| 2025-07-02 | 1.0000                      |
|  |  |
| 2025-07-03 | 1.0000                      |
|  |  |
| 2025-07-07 | 1.0000                      |
|  |  |
| 2025-07-08 | 1.0000                      |
|  |  |
| 2025-07-09 | 1.0001                      |
|  |  |
| 2025-07-10 | 1.0000                      |
|  |  |
| 2025-07-11 | 1.0001                      |
|  |  |
| 2025-07-14 | 1.0000                      |
|  |  |
| 2025-07-15 | 1.0000                      |
|  |  |
| 2025-07-16 | 1.0001                      |
|  |  |
| 2025-07-17 | 1.0000                      |
|  |  |
| 2025-07-18 | 1.0001                      |
|  |  |
| 2025-07-21 | 1.0000                      |
|  |  |
| 2025-07-22 | 1.0001                      |
|  |  |
| 2025-07-23 | 1.0000                      |
|  |  |
| 2025-07-24 | 1.0000                      |
|  |  |
| 2025-07-25 | 1.0001                      |
|  |  |
| 2025-07-28 | 1.0000                      |
|  |  |
| 2025-07-29 | 1.0001                      |
|  |  |
| 2025-07-30 | 1.0000                      |
|  |  |
| 2025-07-31 | 1.0000                      |
|  |  |

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

### Class: Class P

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $475964169.03

- **Number of Shares Outstanding:** 475959626.3100

- **Expense Reimbursement/Waiver:** 20179.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-07-01 | 1.0000          |
|  |  |
| 2025-07-02 | 1.0000          |
|  |  |
| 2025-07-03 | 1.0000          |
|  |  |
| 2025-07-07 | 1.0000          |
|  |  |
| 2025-07-08 | 1.0000          |
|  |  |
| 2025-07-09 | 1.0000          |
|  |  |
| 2025-07-10 | 1.0000          |
|  |  |
| 2025-07-11 | 1.0000          |
|  |  |
| 2025-07-14 | 1.0000          |
|  |  |
| 2025-07-15 | 1.0000          |
|  |  |
| 2025-07-16 | 1.0000          |
|  |  |
| 2025-07-17 | 1.0000          |
|  |  |
| 2025-07-18 | 1.0000          |
|  |  |
| 2025-07-21 | 1.0000          |
|  |  |
| 2025-07-22 | 1.0001          |
|  |  |
| 2025-07-23 | 1.0000          |
|  |  |
| 2025-07-24 | 1.0000          |
|  |  |
| 2025-07-25 | 1.0000          |
|  |  |
| 2025-07-28 | 1.0000          |
|  |  |
| 2025-07-29 | 1.0001          |
|  |  |
| 2025-07-30 | 1.0000          |
|  |  |
| 2025-07-31 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-07-01 | $9928934.88               | $4340400.14             |
| 2025-07-02 | $46793026.16              | $6589767.15             |
| 2025-07-03 | $14529992.67              | $3514061.13             |
| 2025-07-07 | $6285436.34               | $3805123.19             |
| 2025-07-08 | $5210003.65               | $6301202.20             |
| 2025-07-09 | $5117040.45               | $8707055.69             |
| 2025-07-10 | $5302878.24               | $3195861.53             |
| 2025-07-11 | $8861838.93               | $8159913.87             |
| 2025-07-14 | $6742191.43               | $5921904.16             |
| 2025-07-15 | $3155042.24               | $5349883.53             |
| 2025-07-16 | $7579375.26               | $4515110.12             |
| 2025-07-17 | $5732776.92               | $3343865.90             |
| 2025-07-18 | $8041420.19               | $5840772.31             |
| 2025-07-21 | $10524523.46              | $9004597.33             |
| 2025-07-22 | $1938045.83               | $6912762.50             |
| 2025-07-23 | $1909506.50               | $13791009.63            |
| 2025-07-24 | $4445916.36               | $4273373.04             |
| 2025-07-25 | $3565343.13               | $5836449.28             |
| 2025-07-28 | $5474687.27               | $7382634.77             |
| 2025-07-29 | $5065519.61               | $12002246.30            |
| 2025-07-30 | $3272784.63               | $4232679.63             |
| 2025-07-31 | $3599046.96               | $1923157.48             |

**Total Gross Subscriptions (Month):** $173075331.11

**Total Gross Redemptions (Month):** $134943830.88

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-07-01 | 4.1400%           |
| 2025-07-02 | 4.1400%           |
| 2025-07-03 | 4.1300%           |
| 2025-07-07 | 4.1300%           |
| 2025-07-08 | 4.1300%           |
| 2025-07-09 | 4.1300%           |
| 2025-07-10 | 4.1400%           |
| 2025-07-11 | 4.1500%           |
| 2025-07-14 | 4.1500%           |
| 2025-07-15 | 4.1500%           |
| 2025-07-16 | 4.1500%           |
| 2025-07-17 | 4.1600%           |
| 2025-07-18 | 4.1600%           |
| 2025-07-21 | 4.1700%           |
| 2025-07-22 | 4.1700%           |
| 2025-07-23 | 4.1700%           |
| 2025-07-24 | 4.1700%           |
| 2025-07-25 | 4.1800%           |
| 2025-07-28 | 4.1800%           |
| 2025-07-29 | 4.1800%           |
| 2025-07-30 | 4.1800%           |
| 2025-07-31 | 4.1900%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 7.4700%          | 0.0000%              |

### Class: Class T

- **Minimum Initial Investment:** $5000000.00

- **Net Assets of Class:** $5138377584.84

- **Number of Shares Outstanding:** 5138330568.3800

- **Expense Reimbursement/Waiver:** 204269.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-07-01 | 1.0000          |
|  |  |
| 2025-07-02 | 1.0001          |
|  |  |
| 2025-07-03 | 1.0000          |
|  |  |
| 2025-07-07 | 1.0000          |
|  |  |
| 2025-07-08 | 1.0000          |
|  |  |
| 2025-07-09 | 1.0001          |
|  |  |
| 2025-07-10 | 1.0000          |
|  |  |
| 2025-07-11 | 1.0001          |
|  |  |
| 2025-07-14 | 1.0000          |
|  |  |
| 2025-07-15 | 1.0000          |
|  |  |
| 2025-07-16 | 1.0001          |
|  |  |
| 2025-07-17 | 1.0000          |
|  |  |
| 2025-07-18 | 1.0001          |
|  |  |
| 2025-07-21 | 1.0000          |
|  |  |
| 2025-07-22 | 1.0001          |
|  |  |
| 2025-07-23 | 1.0000          |
|  |  |
| 2025-07-24 | 1.0000          |
|  |  |
| 2025-07-25 | 1.0001          |
|  |  |
| 2025-07-28 | 1.0000          |
|  |  |
| 2025-07-29 | 1.0001          |
|  |  |
| 2025-07-30 | 1.0000          |
|  |  |
| 2025-07-31 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-07-01 | $21907823.18              | $89374936.81            |
| 2025-07-02 | $24666959.55              | $40009363.97            |
| 2025-07-03 | $129593798.62             | $1389989.91             |
| 2025-07-07 | $5179493.52               | $30991172.97            |
| 2025-07-08 | $55383191.57              | $8061790.20             |
| 2025-07-09 | $921669.50                | $3361355.30             |
| 2025-07-10 | $246448955.53             | $7689701.97             |
| 2025-07-11 | $51411276.61              | $2122155.59             |
| 2025-07-14 | $4599631.78               | $11042620.46            |
| 2025-07-15 | $60618147.93              | $13571605.70            |
| 2025-07-16 | $17933452.41              | $53332599.26            |
| 2025-07-17 | $257008738.33             | $11640764.08            |
| 2025-07-18 | $1026527.25               | $6720675.88             |
| 2025-07-21 | $195926776.49             | $64762976.17            |
| 2025-07-22 | $11032410.87              | $3040218.64             |
| 2025-07-23 | $249619.40                | $24203060.67            |
| 2025-07-24 | $34481201.82              | $34281827.31            |
| 2025-07-25 | $12009912.63              | $27537680.18            |
| 2025-07-28 | $34146762.21              | $64093208.97            |
| 2025-07-29 | $3609176.00               | $66809050.61            |
| 2025-07-30 | $10752801.58              | $66703838.12            |
| 2025-07-31 | $40618135.60              | $102144331.02           |

**Total Gross Subscriptions (Month):** $1219526462.38

**Total Gross Redemptions (Month):** $732884923.79

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-07-01 | 4.1400%           |
| 2025-07-02 | 4.1400%           |
| 2025-07-03 | 4.1300%           |
| 2025-07-07 | 4.1300%           |
| 2025-07-08 | 4.1300%           |
| 2025-07-09 | 4.1300%           |
| 2025-07-10 | 4.1400%           |
| 2025-07-11 | 4.1500%           |
| 2025-07-14 | 4.1500%           |
| 2025-07-15 | 4.1500%           |
| 2025-07-16 | 4.1500%           |
| 2025-07-17 | 4.1600%           |
| 2025-07-18 | 4.1600%           |
| 2025-07-21 | 4.1700%           |
| 2025-07-22 | 4.1700%           |
| 2025-07-23 | 4.1700%           |
| 2025-07-24 | 4.1700%           |
| 2025-07-25 | 4.1800%           |
| 2025-07-28 | 4.1800%           |
| 2025-07-29 | 4.1800%           |
| 2025-07-30 | 4.1800%           |
| 2025-07-31 | 4.1900%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 5.8700%          | 0.0000%              |

## 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: 549300EBIIAXTNCMYQ69
- **C.18 - Value (incl. sponsor support):** $5634413323.76
- **C.18.a - Value (excl. sponsor support):** $5634413323.76
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-08-01
- **C.12 - Maturity Date (WAL):** 2025-08-01
- **C.13 - Final Legal Maturity Date:** 2025-08-01
- **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:** 2025-08-07

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

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

**Title of Signing Officer:** Vice President