# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-25-014067
**Filing Date:** 2025-10
**Character Count:** 17722
**Document Hash:** 08f061f06852132400be485ded4330b8
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-25-014067.hdr.sgml**: 20251007

**ACCESSION NUMBER**: 0001410368-25-014067

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250930

**FILED AS OF DATE**: 20251007

**DATE AS OF CHANGE**: 20251007

**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:** 251379628

**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):** 2025-09-30

**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:** $6147887251.96

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

- **Cash:** $0.00

- **Total Other Assets:** $89504.87

- **Total Liabilities:** $21315925.66

- **Net Assets of Series:** $6126660831.17

- **Number of Shares Outstanding (Series):** 6126594998.5200

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2025-09-02 | $13514391299.86           | $13514391299.86            | 99.8900%                  | 99.8900%                   |
| 2025-09-03 | $13687976976.64           | $13687976976.64            | 99.8900%                  | 99.8900%                   |
| 2025-09-04 | $13525604137.71           | $13525604137.71            | 99.8800%                  | 99.8800%                   |
| 2025-09-05 | $13745494073.37           | $13745494073.37            | 99.8800%                  | 99.8800%                   |
| 2025-09-08 | $14108191374.00           | $14108191374.00            | 99.8800%                  | 99.8800%                   |
| 2025-09-09 | $13628838141.08           | $13628838141.08            | 99.8700%                  | 99.8700%                   |
| 2025-09-10 | $13702953991.87           | $13702953991.87            | 99.8700%                  | 99.8700%                   |
| 2025-09-11 | $13431053175.75           | $13431053175.75            | 99.8700%                  | 99.8700%                   |
| 2025-09-12 | $13436646225.40           | $13436646225.40            | 99.8600%                  | 99.8600%                   |
| 2025-09-15 | $13538818831.81           | $13538818831.81            | 99.8700%                  | 99.8700%                   |
| 2025-09-16 | $13804888510.10           | $13804888510.10            | 99.8700%                  | 99.8700%                   |
| 2025-09-17 | $13358098445.42           | $13358098445.42            | 99.8600%                  | 99.8600%                   |
| 2025-09-18 | $13383882293.40           | $13383882293.40            | 99.8600%                  | 99.8600%                   |
| 2025-09-19 | $13452974390.60           | $13452974390.60            | 99.8600%                  | 99.8600%                   |
| 2025-09-22 | $13563144376.21           | $13563144376.21            | 99.8600%                  | 99.8600%                   |
| 2025-09-23 | $13500557063.41           | $13500557063.41            | 99.8500%                  | 99.8500%                   |
| 2025-09-24 | $13967009431.69           | $13967009431.69            | 99.8600%                  | 99.8600%                   |
| 2025-09-25 | $13444206054.88           | $13444206054.88            | 99.8500%                  | 99.8500%                   |
| 2025-09-26 | $13564776141.17           | $13564776141.17            | 99.8400%                  | 99.8400%                   |
| 2025-09-29 | $13812223422.87           | $13812223422.87            | 99.8500%                  | 99.8500%                   |
| 2025-09-30 | $13418865569.96           | $13418865569.96            | 99.8600%                  | 99.8600%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-09-02 | 4.3100%             |
| 2025-09-03 | 4.3000%             |
| 2025-09-04 | 4.3000%             |
| 2025-09-05 | 4.2800%             |
| 2025-09-08 | 4.2800%             |
| 2025-09-09 | 4.2700%             |
| 2025-09-10 | 4.2700%             |
| 2025-09-11 | 4.2600%             |
| 2025-09-12 | 4.2500%             |
| 2025-09-15 | 4.2400%             |
| 2025-09-16 | 4.2400%             |
| 2025-09-17 | 4.2400%             |
| 2025-09-18 | 4.2300%             |
| 2025-09-19 | 4.2100%             |
| 2025-09-22 | 4.2100%             |
| 2025-09-23 | 4.2000%             |
| 2025-09-24 | 4.2000%             |
| 2025-09-25 | 4.2000%             |
| 2025-09-26 | 4.1800%             |
| 2025-09-29 | 4.1800%             |
| 2025-09-30 | 4.1800%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-09-02 | 1.0001                      |
|  |  |
| 2025-09-03 | 1.0001                      |
|  |  |
| 2025-09-04 | 1.0002                      |
|  |  |
| 2025-09-05 | 1.0002                      |
|  |  |
| 2025-09-08 | 1.0002                      |
|  |  |
| 2025-09-09 | 1.0002                      |
|  |  |
| 2025-09-10 | 1.0002                      |
|  |  |
| 2025-09-11 | 1.0002                      |
|  |  |
| 2025-09-12 | 1.0002                      |
|  |  |
| 2025-09-15 | 1.0002                      |
|  |  |
| 2025-09-16 | 1.0002                      |
|  |  |
| 2025-09-17 | 1.0002                      |
|  |  |
| 2025-09-18 | 1.0002                      |
|  |  |
| 2025-09-19 | 1.0002                      |
|  |  |
| 2025-09-22 | 1.0002                      |
|  |  |
| 2025-09-23 | 1.0002                      |
|  |  |
| 2025-09-24 | 1.0002                      |
|  |  |
| 2025-09-25 | 1.0001                      |
|  |  |
| 2025-09-26 | 1.0001                      |
|  |  |
| 2025-09-29 | 1.0001                      |
|  |  |
| 2025-09-30 | 1.0001                      |
|  |  |

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

### Class: Class P

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $428316390.86

- **Number of Shares Outstanding:** 428310807.7000

- **Expense Reimbursement/Waiver:** 17074.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-09-02 | 1.0002          |
|  |  |
| 2025-09-03 | 1.0002          |
|  |  |
| 2025-09-04 | 1.0002          |
|  |  |
| 2025-09-05 | 1.0002          |
|  |  |
| 2025-09-08 | 1.0002          |
|  |  |
| 2025-09-09 | 1.0002          |
|  |  |
| 2025-09-10 | 1.0002          |
|  |  |
| 2025-09-11 | 1.0002          |
|  |  |
| 2025-09-12 | 1.0002          |
|  |  |
| 2025-09-15 | 1.0002          |
|  |  |
| 2025-09-16 | 1.0002          |
|  |  |
| 2025-09-17 | 1.0002          |
|  |  |
| 2025-09-18 | 1.0002          |
|  |  |
| 2025-09-19 | 1.0002          |
|  |  |
| 2025-09-22 | 1.0002          |
|  |  |
| 2025-09-23 | 1.0002          |
|  |  |
| 2025-09-24 | 1.0002          |
|  |  |
| 2025-09-25 | 1.0001          |
|  |  |
| 2025-09-26 | 1.0001          |
|  |  |
| 2025-09-29 | 1.0001          |
|  |  |
| 2025-09-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-09-02 | $4745923.15               | $6012137.08             |
| 2025-09-03 | $9531390.76               | $4210299.50             |
| 2025-09-04 | $4210050.76               | $4916895.51             |
| 2025-09-05 | $9162941.40               | $1726820.47             |
| 2025-09-08 | $5190665.78               | $2954938.14             |
| 2025-09-09 | $4650383.80               | $11040875.05            |
| 2025-09-10 | $5602160.16               | $5319898.11             |
| 2025-09-11 | $3288611.30               | $16573784.06            |
| 2025-09-12 | $6252245.51               | $6546069.29             |
| 2025-09-15 | $2602215.18               | $2905726.29             |
| 2025-09-16 | $3352547.60               | $7877213.72             |
| 2025-09-17 | $10478283.31              | $3876287.31             |
| 2025-09-18 | $24003404.36              | $6058861.81             |
| 2025-09-19 | $14101341.54              | $3137116.71             |
| 2025-09-22 | $4866317.06               | $6827166.59             |
| 2025-09-23 | $3019207.57               | $12577068.64            |
| 2025-09-24 | $13314480.41              | $8485561.02             |
| 2025-09-25 | $4199834.05               | $10239178.03            |
| 2025-09-26 | $7870938.39               | $4658832.25             |
| 2025-09-29 | $5734088.12               | $28358408.80            |
| 2025-09-30 | $2432442.57               | $7226507.09             |

**Total Gross Subscriptions (Month):** $148609472.78

**Total Gross Redemptions (Month):** $161529645.47

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-09-02 | 4.1700%           |
| 2025-09-03 | 4.1600%           |
| 2025-09-04 | 4.1600%           |
| 2025-09-05 | 4.1400%           |
| 2025-09-08 | 4.1400%           |
| 2025-09-09 | 4.1300%           |
| 2025-09-10 | 4.1300%           |
| 2025-09-11 | 4.1200%           |
| 2025-09-12 | 4.1100%           |
| 2025-09-15 | 4.1000%           |
| 2025-09-16 | 4.1000%           |
| 2025-09-17 | 4.1000%           |
| 2025-09-18 | 4.0900%           |
| 2025-09-19 | 4.0700%           |
| 2025-09-22 | 4.0700%           |
| 2025-09-23 | 4.0600%           |
| 2025-09-24 | 4.0600%           |
| 2025-09-25 | 4.0600%           |
| 2025-09-26 | 4.0400%           |
| 2025-09-29 | 4.0400%           |
| 2025-09-30 | 4.0400%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 5.0300%          | 0.0000%              |

### Class: Class T

- **Minimum Initial Investment:** $5000000.00

- **Net Assets of Class:** $5698344440.31

- **Number of Shares Outstanding:** 5698284190.8200

- **Expense Reimbursement/Waiver:** 210542.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-09-02 | 1.0001          |
|  |  |
| 2025-09-03 | 1.0001          |
|  |  |
| 2025-09-04 | 1.0002          |
|  |  |
| 2025-09-05 | 1.0002          |
|  |  |
| 2025-09-08 | 1.0002          |
|  |  |
| 2025-09-09 | 1.0002          |
|  |  |
| 2025-09-10 | 1.0002          |
|  |  |
| 2025-09-11 | 1.0002          |
|  |  |
| 2025-09-12 | 1.0002          |
|  |  |
| 2025-09-15 | 1.0002          |
|  |  |
| 2025-09-16 | 1.0002          |
|  |  |
| 2025-09-17 | 1.0002          |
|  |  |
| 2025-09-18 | 1.0002          |
|  |  |
| 2025-09-19 | 1.0002          |
|  |  |
| 2025-09-22 | 1.0002          |
|  |  |
| 2025-09-23 | 1.0002          |
|  |  |
| 2025-09-24 | 1.0002          |
|  |  |
| 2025-09-25 | 1.0001          |
|  |  |
| 2025-09-26 | 1.0001          |
|  |  |
| 2025-09-29 | 1.0001          |
|  |  |
| 2025-09-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-09-02 | $75393276.67              | $20245339.72            |
| 2025-09-03 | $32468002.26              | $13506648.87            |
| 2025-09-04 | $41538874.20              | $178884578.64           |
| 2025-09-05 | $168802377.34             | $14264105.60            |
| 2025-09-08 | $2293071.71               | $13640851.98            |
| 2025-09-09 | $3729432.78               | $12353093.47            |
| 2025-09-10 | $7661904.03               | $23472604.67            |
| 2025-09-11 | $23357850.17              | $169419710.73           |
| 2025-09-12 | $20623560.87              | $6581940.44             |
| 2025-09-15 | $14520575.64              | $24342768.61            |
| 2025-09-16 | $587632317.13             | $82877807.19            |
| 2025-09-17 | $14465733.13              | $571255351.10           |
| 2025-09-18 | $212903862.04             | $25524406.70            |
| 2025-09-19 | $96897633.95              | $15631356.26            |
| 2025-09-22 | $46139173.34              | $54133734.29            |
| 2025-09-23 | $10488600.23              | $38075982.30            |
| 2025-09-24 | $19834328.58              | $52483885.80            |
| 2025-09-25 | $24648471.15              | $48584151.98            |
| 2025-09-26 | $21638198.08              | $19962080.06            |
| 2025-09-29 | $1682826.80               | $9385221.32             |
| 2025-09-30 | $3111985.80               | $17634304.43            |

**Total Gross Subscriptions (Month):** $1429832055.90

**Total Gross Redemptions (Month):** $1412259924.16

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-09-02 | 4.1700%           |
| 2025-09-03 | 4.1600%           |
| 2025-09-04 | 4.1600%           |
| 2025-09-05 | 4.1400%           |
| 2025-09-08 | 4.1400%           |
| 2025-09-09 | 4.1300%           |
| 2025-09-10 | 4.1300%           |
| 2025-09-11 | 4.1200%           |
| 2025-09-12 | 4.1100%           |
| 2025-09-15 | 4.1000%           |
| 2025-09-16 | 4.1000%           |
| 2025-09-17 | 4.1000%           |
| 2025-09-18 | 4.0900%           |
| 2025-09-19 | 4.0700%           |
| 2025-09-22 | 4.0700%           |
| 2025-09-23 | 4.0600%           |
| 2025-09-24 | 4.0600%           |
| 2025-09-25 | 4.0600%           |
| 2025-09-26 | 4.0400%           |
| 2025-09-29 | 4.0400%           |
| 2025-09-30 | 4.0400%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 5.3300%          | 0.0000%              |
| Retail investor |  | 5.3300%          | 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):** $6147887251.96
- **C.18.a - Value (excl. sponsor support):** $6147887251.96
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-10-01
- **C.12 - Maturity Date (WAL):** 2025-10-01
- **C.13 - Final Legal Maturity Date:** 2025-10-01
- **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:** 2025-10-07

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

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

**Title of Signing Officer:** Vice President