# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001145549-25-058047
**Filing Date:** 2025-9
**Character Count:** 13627
**Document Hash:** 7f7e271ad5b2e41e8025cff01dc2113a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-058047.hdr.sgml**: 20250908

**ACCESSION NUMBER**: 0001145549-25-058047

**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:** 251299400

**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 Institutional Fund (Series ID: S000084282)

| Class ID   | Class Name                                     | Ticker Symbol   |
|:---|:---|:---|
| C000248579 | UBS Select 100% US Treasury Institutional Fund | SIOXX           |

# 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 Institutional Fund

**LEI of Series:** 529900KWG787B4G5P791

**EDGAR Series Identifier:** S000084282

**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:** $7003620424.66

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

- **Cash:** $0.00

- **Total Other Assets:** $75241.49

- **Total Liabilities:** $26068419.26

- **Net Assets of Series:** $6977627246.89

- **Number of Shares Outstanding (Series):** 6977546518.3500

- **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: Single Class

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $6977627246.89

- **Number of Shares Outstanding:** 6977546518.3500

- **Expense Reimbursement/Waiver:** 37750.00

**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 | 1.0002          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-08-01 | $89546606.84              | $50613101.59            |
| 2025-08-04 | $59453621.97              | $29648346.01            |
| 2025-08-05 | $68238294.01              | $50210888.68            |
| 2025-08-06 | $59500588.18              | $31572320.99            |
| 2025-08-07 | $50376430.56              | $30775047.16            |
| 2025-08-08 | $67089080.20              | $39762876.71            |
| 2025-08-11 | $23141535.33              | $33554429.14            |
| 2025-08-12 | $40104352.33              | $46562935.54            |
| 2025-08-13 | $63317725.42              | $28694845.73            |
| 2025-08-14 | $30875913.73              | $49567116.63            |
| 2025-08-15 | $179602990.41             | $37022832.03            |
| 2025-08-18 | $57272254.30              | $34583754.98            |
| 2025-08-19 | $57709392.96              | $27615113.10            |
| 2025-08-20 | $95064470.60              | $37377387.00            |
| 2025-08-21 | $48358536.96              | $25133142.81            |
| 2025-08-22 | $51203321.08              | $34406557.76            |
| 2025-08-25 | $41514298.27              | $75103353.20            |
| 2025-08-26 | $37694612.57              | $36537017.99            |
| 2025-08-27 | $33991255.27              | $50187690.81            |
| 2025-08-28 | $119175723.19             | $29728989.57            |
| 2025-08-29 | $46451039.03              | $25765881.11            |

**Total Gross Subscriptions (Month):** $1319682043.21

**Total Gross Redemptions (Month):** $804423628.54

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-08-01 | 4.1500%           |
| 2025-08-04 | 4.1500%           |
| 2025-08-05 | 4.1500%           |
| 2025-08-06 | 4.1500%           |
| 2025-08-07 | 4.1500%           |
| 2025-08-08 | 4.1400%           |
| 2025-08-11 | 4.1400%           |
| 2025-08-12 | 4.1400%           |
| 2025-08-13 | 4.1400%           |
| 2025-08-14 | 4.1400%           |
| 2025-08-15 | 4.1400%           |
| 2025-08-18 | 4.1400%           |
| 2025-08-19 | 4.1400%           |
| 2025-08-20 | 4.1400%           |
| 2025-08-21 | 4.1400%           |
| 2025-08-22 | 4.1400%           |
| 2025-08-25 | 4.1400%           |
| 2025-08-26 | 4.1400%           |
| 2025-08-27 | 4.1400%           |
| 2025-08-28 | 4.1300%           |
| 2025-08-29 | 4.1300%           |

## 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):** $7003620424.66
- **C.18.a - Value (excl. sponsor support):** $7003620424.66
- **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