# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001145549-25-046128
**Filing Date:** 2025-7
**Character Count:** 17069
**Document Hash:** 9a84f1fd80541fe70147559cced4ce31
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-046128.hdr.sgml**: 20250708

**ACCESSION NUMBER**: 0001145549-25-046128

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250630

**FILED AS OF DATE**: 20250708

**DATE AS OF CHANGE**: 20250708

**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:** 251110728

**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):** 2025-06-30

**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:** $5106771453.07

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

- **Cash:** $0.00

- **Total Other Assets:** $109253.91

- **Total Liabilities:** $17312225.59

- **Net Assets of Series:** $5089568481.39

- **Number of Shares Outstanding (Series):** 5089517155.8700

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2025-06-02 | $11582000510.80           | $11582000510.80            | 99.9100%                  | 99.9100%                   |
| 2025-06-03 | $11155845626.11           | $11155845626.11            | 99.9000%                  | 99.9000%                   |
| 2025-06-04 | $11638285341.77           | $11638285341.77            | 99.9000%                  | 99.9000%                   |
| 2025-06-05 | $11317436481.34           | $11317436481.34            | 99.8900%                  | 99.8900%                   |
| 2025-06-06 | $11291544731.08           | $11291544731.08            | 99.8800%                  | 99.8800%                   |
| 2025-06-09 | $11238030223.40           | $11238030223.40            | 99.8800%                  | 99.8800%                   |
| 2025-06-10 | $11232162748.78           | $11232162748.78            | 99.8800%                  | 99.8800%                   |
| 2025-06-11 | $11189452676.40           | $11189452676.40            | 99.8700%                  | 99.8700%                   |
| 2025-06-12 | $11422324937.68           | $11422324937.68            | 99.8700%                  | 99.8700%                   |
| 2025-06-13 | $11389599277.42           | $11389599277.42            | 99.8700%                  | 99.8700%                   |
| 2025-06-16 | $11652403878.32           | $11652403878.32            | 99.8700%                  | 99.8700%                   |
| 2025-06-17 | $11508414786.95           | $11508414786.95            | 99.8600%                  | 99.8600%                   |
| 2025-06-18 | $11960191631.89           | $11960191631.89            | 99.8600%                  | 99.8600%                   |
| 2025-06-20 | $11523617944.27           | $11523617944.27            | 99.8500%                  | 99.8500%                   |
| 2025-06-23 | $11634972398.19           | $11634972398.19            | 99.8500%                  | 99.8500%                   |
| 2025-06-24 | $11559722706.22           | $11559722706.22            | 99.8400%                  | 99.8400%                   |
| 2025-06-25 | $11909532409.54           | $11909532409.54            | 99.8400%                  | 99.8400%                   |
| 2025-06-26 | $11763553191.25           | $11763553191.25            | 99.8400%                  | 99.8400%                   |
| 2025-06-27 | $11707862211.32           | $11707862211.32            | 99.8300%                  | 99.8300%                   |
| 2025-06-30 | $11803550570.88           | $11803550570.88            | 99.8300%                  | 99.8300%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-06-02 | 4.3300%             |
| 2025-06-03 | 4.3300%             |
| 2025-06-04 | 4.3300%             |
| 2025-06-05 | 4.3200%             |
| 2025-06-06 | 4.3200%             |
| 2025-06-09 | 4.3200%             |
| 2025-06-10 | 4.3200%             |
| 2025-06-11 | 4.3200%             |
| 2025-06-12 | 4.3200%             |
| 2025-06-13 | 4.3100%             |
| 2025-06-16 | 4.3100%             |
| 2025-06-17 | 4.3100%             |
| 2025-06-18 | 4.3100%             |
| 2025-06-20 | 4.3100%             |
| 2025-06-23 | 4.3100%             |
| 2025-06-24 | 4.3100%             |
| 2025-06-25 | 4.3000%             |
| 2025-06-26 | 4.3000%             |
| 2025-06-27 | 4.2900%             |
| 2025-06-30 | 4.2900%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-06-02 | 1.0001                      |
|  |  |
| 2025-06-03 | 1.0001                      |
|  |  |
| 2025-06-04 | 1.0001                      |
|  |  |
| 2025-06-05 | 1.0001                      |
|  |  |
| 2025-06-06 | 1.0000                      |
|  |  |
| 2025-06-09 | 1.0001                      |
|  |  |
| 2025-06-10 | 1.0001                      |
|  |  |
| 2025-06-11 | 1.0001                      |
|  |  |
| 2025-06-12 | 1.0001                      |
|  |  |
| 2025-06-13 | 1.0001                      |
|  |  |
| 2025-06-16 | 1.0001                      |
|  |  |
| 2025-06-17 | 1.0001                      |
|  |  |
| 2025-06-18 | 1.0001                      |
|  |  |
| 2025-06-20 | 1.0001                      |
|  |  |
| 2025-06-23 | 1.0001                      |
|  |  |
| 2025-06-24 | 1.0001                      |
|  |  |
| 2025-06-25 | 1.0001                      |
|  |  |
| 2025-06-26 | 1.0001                      |
|  |  |
| 2025-06-27 | 1.0001                      |
|  |  |
| 2025-06-30 | 1.0001                      |
|  |  |

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

### Class: Class P

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $437832646.86

- **Number of Shares Outstanding:** 437828126.0800

- **Expense Reimbursement/Waiver:** 17266.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-06-02 | 1.0001          |
|  |  |
| 2025-06-03 | 1.0001          |
|  |  |
| 2025-06-04 | 1.0001          |
|  |  |
| 2025-06-05 | 1.0001          |
|  |  |
| 2025-06-06 | 1.0000          |
|  |  |
| 2025-06-09 | 1.0000          |
|  |  |
| 2025-06-10 | 1.0000          |
|  |  |
| 2025-06-11 | 1.0001          |
|  |  |
| 2025-06-12 | 1.0001          |
|  |  |
| 2025-06-13 | 1.0001          |
|  |  |
| 2025-06-16 | 1.0001          |
|  |  |
| 2025-06-17 | 1.0001          |
|  |  |
| 2025-06-18 | 1.0001          |
|  |  |
| 2025-06-20 | 1.0001          |
|  |  |
| 2025-06-23 | 1.0001          |
|  |  |
| 2025-06-24 | 1.0001          |
|  |  |
| 2025-06-25 | 1.0001          |
|  |  |
| 2025-06-26 | 1.0001          |
|  |  |
| 2025-06-27 | 1.0001          |
|  |  |
| 2025-06-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-06-02 | $3612122.40               | $2858973.70             |
| 2025-06-03 | $12500301.41              | $8226857.07             |
| 2025-06-04 | $10023608.58              | $6919873.19             |
| 2025-06-05 | $34401322.54              | $5741375.37             |
| 2025-06-06 | $40768211.74              | $4896280.18             |
| 2025-06-09 | $7493312.82               | $2849312.99             |
| 2025-06-10 | $2593056.58               | $4028395.58             |
| 2025-06-11 | $1950455.28               | $10012048.33            |
| 2025-06-12 | $2745158.33               | $8473575.00             |
| 2025-06-13 | $3052547.45               | $49401251.61            |
| 2025-06-16 | $5260495.62               | $5853931.20             |
| 2025-06-17 | $8292725.65               | $4692274.55             |
| 2025-06-18 | $16232193.91              | $6542656.98             |
| 2025-06-20 | $7329607.44               | $4802432.41             |
| 2025-06-23 | $3329935.69               | $3541009.96             |
| 2025-06-24 | $3634164.40               | $7279422.94             |
| 2025-06-25 | $6898252.00               | $6978846.07             |
| 2025-06-26 | $10694009.85              | $6236056.33             |
| 2025-06-27 | $2229917.70               | $7704865.88             |
| 2025-06-30 | $1670202.33               | $4551295.78             |

**Total Gross Subscriptions (Month):** $184711601.72

**Total Gross Redemptions (Month):** $161590735.12

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-06-02 | 4.1900%           |
| 2025-06-03 | 4.1900%           |
| 2025-06-04 | 4.1900%           |
| 2025-06-05 | 4.1800%           |
| 2025-06-06 | 4.1800%           |
| 2025-06-09 | 4.1800%           |
| 2025-06-10 | 4.1800%           |
| 2025-06-11 | 4.1800%           |
| 2025-06-12 | 4.1800%           |
| 2025-06-13 | 4.1700%           |
| 2025-06-16 | 4.1700%           |
| 2025-06-17 | 4.1700%           |
| 2025-06-18 | 4.1700%           |
| 2025-06-20 | 4.1700%           |
| 2025-06-23 | 4.1700%           |
| 2025-06-24 | 4.1700%           |
| 2025-06-25 | 4.1600%           |
| 2025-06-26 | 4.1600%           |
| 2025-06-27 | 4.1500%           |
| 2025-06-30 | 4.1500%           |

### Class: Class T

- **Minimum Initial Investment:** $5000000.00

- **Net Assets of Class:** $4651735834.53

- **Number of Shares Outstanding:** 4651689029.7900

- **Expense Reimbursement/Waiver:** 169944.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-06-02 | 1.0001          |
|  |  |
| 2025-06-03 | 1.0001          |
|  |  |
| 2025-06-04 | 1.0001          |
|  |  |
| 2025-06-05 | 1.0001          |
|  |  |
| 2025-06-06 | 1.0001          |
|  |  |
| 2025-06-09 | 1.0001          |
|  |  |
| 2025-06-10 | 1.0001          |
|  |  |
| 2025-06-11 | 1.0001          |
|  |  |
| 2025-06-12 | 1.0001          |
|  |  |
| 2025-06-13 | 1.0001          |
|  |  |
| 2025-06-16 | 1.0001          |
|  |  |
| 2025-06-17 | 1.0001          |
|  |  |
| 2025-06-18 | 1.0001          |
|  |  |
| 2025-06-20 | 1.0001          |
|  |  |
| 2025-06-23 | 1.0001          |
|  |  |
| 2025-06-24 | 1.0002          |
|  |  |
| 2025-06-25 | 1.0001          |
|  |  |
| 2025-06-26 | 1.0001          |
|  |  |
| 2025-06-27 | 1.0001          |
|  |  |
| 2025-06-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-06-02 | $349146472.13             | $90081320.74            |
| 2025-06-03 | $789416225.01             | $2826553.98             |
| 2025-06-04 | $17912555.08              | $34336564.92            |
| 2025-06-05 | $27509174.13              | $84253459.81            |
| 2025-06-06 | $25826405.30              | $4226349.67             |
| 2025-06-09 | $1997924.26               | $16739263.55            |
| 2025-06-10 | $17452416.17              | $16105903.27            |
| 2025-06-11 | $4406340.63               | $30827465.51            |
| 2025-06-12 | $318036983.92             | $67128773.18            |
| 2025-06-13 | $1270599.92               | $10455848.46            |
| 2025-06-16 | $15283953.95              | $13284548.26            |
| 2025-06-17 | $37686252.62              | $21449638.46            |
| 2025-06-18 | $39829463.27              | $8704334.89             |
| 2025-06-20 | $6249468.48               | $52644602.25            |
| 2025-06-23 | $119282892.68             | $7846203.87             |
| 2025-06-24 | $169018535.79             | $50581719.36            |
| 2025-06-25 | $10929262.79              | $51301873.84            |
| 2025-06-26 | $5674049.94               | $12723715.06            |
| 2025-06-27 | $11901443.72              | $5627962.96             |
| 2025-06-30 | $16939549.59              | $23879029.49            |

**Total Gross Subscriptions (Month):** $1985769969.38

**Total Gross Redemptions (Month):** $605025131.53

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-06-02 | 4.1900%           |
| 2025-06-03 | 4.1900%           |
| 2025-06-04 | 4.1900%           |
| 2025-06-05 | 4.1800%           |
| 2025-06-06 | 4.1800%           |
| 2025-06-09 | 4.1800%           |
| 2025-06-10 | 4.1800%           |
| 2025-06-11 | 4.1800%           |
| 2025-06-12 | 4.1800%           |
| 2025-06-13 | 4.1700%           |
| 2025-06-16 | 4.1700%           |
| 2025-06-17 | 4.1700%           |
| 2025-06-18 | 4.1700%           |
| 2025-06-20 | 4.1700%           |
| 2025-06-23 | 4.1700%           |
| 2025-06-24 | 4.1700%           |
| 2025-06-25 | 4.1600%           |
| 2025-06-26 | 4.1600%           |
| 2025-06-27 | 4.1500%           |
| 2025-06-30 | 4.1500%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 6.4700%          | 0.0000%              |
| Retail investor |  | 5.1700%          | 0.0000%              |
| Retail investor |  | 5.5700%          | 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):** $5106771453.07
- **C.18.a - Value (excl. sponsor support):** $5106771453.07
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-07-01
- **C.12 - Maturity Date (WAL):** 2025-07-01
- **C.13 - Final Legal Maturity Date:** 2025-07-01
- **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:** 2025-07-08

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

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

**Title of Signing Officer:** Vice President