# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001145549-25-058040
**Filing Date:** 2025-9
**Character Count:** 17720
**Document Hash:** d6d2ced9daf2e037bcb68752a63197bd
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-058040.hdr.sgml**: 20250908

**ACCESSION NUMBER**: 0001145549-25-058040

**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:** 251299395

**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):** 2025-08-31

**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:** $6144145280.02

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

- **Cash:** $0.00

- **Total Other Assets:** $95745.36

- **Total Liabilities:** $22246296.49

- **Net Assets of Series:** $6121994728.89

- **Number of Shares Outstanding (Series):** 6121943039.4700

- **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 | $12571721893.86           | $12571721893.86            | 99.9500%                  | 99.9500%                   |
| 2025-08-04 | $12775638571.61           | $12775638571.61            | 99.9400%                  | 99.9400%                   |
| 2025-08-05 | $12551785010.93           | $12551785010.93            | 99.9400%                  | 99.9400%                   |
| 2025-08-06 | $12876018830.80           | $12876018830.80            | 99.9400%                  | 99.9400%                   |
| 2025-08-07 | $12654048521.85           | $12654048521.85            | 99.9400%                  | 99.9400%                   |
| 2025-08-08 | $12679964337.12           | $12679964337.12            | 99.9300%                  | 99.9300%                   |
| 2025-08-11 | $12994382756.05           | $12994382756.05            | 99.9300%                  | 99.9300%                   |
| 2025-08-12 | $12642057328.42           | $12642057328.42            | 99.9300%                  | 99.9300%                   |
| 2025-08-13 | $13081795847.76           | $13081795847.76            | 99.9300%                  | 99.9300%                   |
| 2025-08-14 | $12758638141.96           | $12758638141.96            | 99.9200%                  | 99.9200%                   |
| 2025-08-15 | $12864480527.66           | $12864480527.66            | 99.9200%                  | 99.9200%                   |
| 2025-08-18 | $13263846183.27           | $13263846183.27            | 99.9200%                  | 99.9200%                   |
| 2025-08-19 | $12794250666.86           | $12794250666.86            | 99.9100%                  | 99.9100%                   |
| 2025-08-20 | $13247120932.97           | $13247120932.97            | 99.9100%                  | 99.9100%                   |
| 2025-08-21 | $13325308134.07           | $13325308134.07            | 99.9100%                  | 99.9100%                   |
| 2025-08-22 | $13369278767.03           | $13369278767.03            | 99.9100%                  | 99.9100%                   |
| 2025-08-25 | $13633551458.69           | $13633551458.69            | 99.9100%                  | 99.9100%                   |
| 2025-08-26 | $13409548901.48           | $13409548901.48            | 99.9000%                  | 99.9000%                   |
| 2025-08-27 | $13583142881.21           | $13583142881.21            | 99.9000%                  | 99.9000%                   |
| 2025-08-28 | $13558884078.08           | $13558884078.08            | 99.9000%                  | 99.9000%                   |
| 2025-08-29 | $13492130554.11           | $13492130554.11            | 99.8900%                  | 99.8900%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-08-01 | 4.3300%             |
| 2025-08-04 | 4.3300%             |
| 2025-08-05 | 4.3300%             |
| 2025-08-06 | 4.3300%             |
| 2025-08-07 | 4.3300%             |
| 2025-08-08 | 4.3200%             |
| 2025-08-11 | 4.3200%             |
| 2025-08-12 | 4.3200%             |
| 2025-08-13 | 4.3200%             |
| 2025-08-14 | 4.3200%             |
| 2025-08-15 | 4.3200%             |
| 2025-08-18 | 4.3200%             |
| 2025-08-19 | 4.3200%             |
| 2025-08-20 | 4.3200%             |
| 2025-08-21 | 4.3200%             |
| 2025-08-22 | 4.3200%             |
| 2025-08-25 | 4.3200%             |
| 2025-08-26 | 4.3200%             |
| 2025-08-27 | 4.3200%             |
| 2025-08-28 | 4.3100%             |
| 2025-08-29 | 4.3100%             |

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

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

### Class: Class P

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $441235532.55

- **Number of Shares Outstanding:** 441230980.3900

- **Expense Reimbursement/Waiver:** 19191.00

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

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-08-01 | $6106402.85               | $16390150.91            |
| 2025-08-04 | $9560031.12               | $4320944.71             |
| 2025-08-05 | $13434965.69              | $5295684.01             |
| 2025-08-06 | $5871884.39               | $4637720.98             |
| 2025-08-07 | $6039716.97               | $3416429.26             |
| 2025-08-08 | $4765286.17               | $5232865.28             |
| 2025-08-11 | $2387596.30               | $8402282.47             |
| 2025-08-12 | $4416256.15               | $12785585.00            |
| 2025-08-13 | $6314458.88               | $3943588.81             |
| 2025-08-14 | $3185342.80               | $4258736.39             |
| 2025-08-15 | $1766817.47               | $36810676.45            |
| 2025-08-18 | $2856107.53               | $7354796.15             |
| 2025-08-19 | $4212111.93               | $8297465.14             |
| 2025-08-20 | $5676573.01               | $5430626.49             |
| 2025-08-21 | $1891733.25               | $4354401.06             |
| 2025-08-22 | $24472995.58              | $1304272.44             |
| 2025-08-25 | $7316470.03               | $4534126.35             |
| 2025-08-26 | $1463009.89               | $4167727.14             |
| 2025-08-27 | $2336980.31               | $2936569.83             |
| 2025-08-28 | $1324622.89               | $5019904.56             |
| 2025-08-29 | $4147385.14               | $5380840.84             |

**Total Gross Subscriptions (Month):** $119546748.35

**Total Gross Redemptions (Month):** $154275394.27

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-08-01 | 4.1900%           |
| 2025-08-04 | 4.1900%           |
| 2025-08-05 | 4.1900%           |
| 2025-08-06 | 4.1900%           |
| 2025-08-07 | 4.1900%           |
| 2025-08-08 | 4.1800%           |
| 2025-08-11 | 4.1800%           |
| 2025-08-12 | 4.1800%           |
| 2025-08-13 | 4.1800%           |
| 2025-08-14 | 4.1800%           |
| 2025-08-15 | 4.1800%           |
| 2025-08-18 | 4.1800%           |
| 2025-08-19 | 4.1800%           |
| 2025-08-20 | 4.1800%           |
| 2025-08-21 | 4.1800%           |
| 2025-08-22 | 4.1800%           |
| 2025-08-25 | 4.1800%           |
| 2025-08-26 | 4.1800%           |
| 2025-08-27 | 4.1800%           |
| 2025-08-28 | 4.1700%           |
| 2025-08-29 | 4.1700%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 5.9000%          | 0.0000%              |

### Class: Class T

- **Minimum Initial Investment:** $5000000.00

- **Net Assets of Class:** $5680759196.34

- **Number of Shares Outstanding:** 5680712059.0800

- **Expense Reimbursement/Waiver:** 221028.00

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

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-08-01 | $167719733.04             | $69912668.71            |
| 2025-08-04 | $4667083.36               | $18053959.15            |
| 2025-08-05 | $6029364.00               | $13570864.14            |
| 2025-08-06 | $13287337.47              | $9717121.43             |
| 2025-08-07 | $21008526.92              | $7760435.85             |
| 2025-08-08 | $11265323.07              | $15733281.24            |
| 2025-08-11 | $16059466.47              | $7561864.76             |
| 2025-08-12 | $76203997.34              | $3901283.57             |
| 2025-08-13 | $837274.41                | $20959439.56            |
| 2025-08-14 | $1952665.45               | $10653130.37            |
| 2025-08-15 | $5060886.45               | $9810403.73             |
| 2025-08-18 | $19979226.51              | $24598211.44            |
| 2025-08-19 | $4801451.72               | $55961180.17            |
| 2025-08-20 | $118667332.78             | $16413226.42            |
| 2025-08-21 | $333200392.74             | $20234089.04            |
| 2025-08-22 | $19447525.10              | $19926481.92            |
| 2025-08-25 | $11352836.29              | $14603839.80            |
| 2025-08-26 | $44631933.54              | $12230279.32            |
| 2025-08-27 | $75648859.09              | $48534755.99            |
| 2025-08-28 | $25922358.29              | $8797936.95             |
| 2025-08-29 | $19106901.36              | $45534531.14            |

**Total Gross Subscriptions (Month):** $996850475.40

**Total Gross Redemptions (Month):** $454468984.70

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-08-01 | 4.1900%           |
| 2025-08-04 | 4.1900%           |
| 2025-08-05 | 4.1900%           |
| 2025-08-06 | 4.1900%           |
| 2025-08-07 | 4.1900%           |
| 2025-08-08 | 4.1800%           |
| 2025-08-11 | 4.1800%           |
| 2025-08-12 | 4.1800%           |
| 2025-08-13 | 4.1800%           |
| 2025-08-14 | 4.1800%           |
| 2025-08-15 | 4.1800%           |
| 2025-08-18 | 4.1800%           |
| 2025-08-19 | 4.1800%           |
| 2025-08-20 | 4.1800%           |
| 2025-08-21 | 4.1800%           |
| 2025-08-22 | 4.1800%           |
| 2025-08-25 | 4.1800%           |
| 2025-08-26 | 4.1800%           |
| 2025-08-27 | 4.1800%           |
| 2025-08-28 | 4.1700%           |
| 2025-08-29 | 4.1700%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 5.3300%          | 0.0000%              |
| Retail investor |  | 5.3200%          | 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):** $6144145280.02
- **C.18.a - Value (excl. sponsor support):** $6144145280.02
- **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