# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-25-014068
**Filing Date:** 2025-10
**Character Count:** 13628
**Document Hash:** 12e8c9c15d9bcee0ad5f823c756c7b7c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-25-014068.hdr.sgml**: 20251007

**ACCESSION NUMBER**: 0001410368-25-014068

**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:** 251379629

**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):** 2025-09-30

**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:** $7021900618.02

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

- **Cash:** $0.00

- **Total Other Assets:** $68821.54

- **Total Liabilities:** $24865460.47

- **Net Assets of Series:** $6997103979.09

- **Number of Shares Outstanding (Series):** 6997006799.1900

- **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 | 1.0002                      |
|  |  |
| 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                      |
|  |  |

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

### Class: Single Class

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $6997103979.09

- **Number of Shares Outstanding:** 6997006799.1900

- **Expense Reimbursement/Waiver:** 33475.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-09-02 | 1.0001          |
|  |  |
| 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 | $89522392.80              | $47616879.46            |
| 2025-09-03 | $55614216.79              | $37936295.01            |
| 2025-09-04 | $83050515.07              | $48711704.15            |
| 2025-09-05 | $82257728.36              | $28540144.84            |
| 2025-09-08 | $27951268.35              | $55354215.37            |
| 2025-09-09 | $45615218.04              | $49580019.79            |
| 2025-09-10 | $58193656.39              | $101200874.98           |
| 2025-09-11 | $43743011.45              | $97468836.86            |
| 2025-09-12 | $56585131.05              | $67790563.72            |
| 2025-09-15 | $53657235.78              | $41179094.37            |
| 2025-09-16 | $84268377.37              | $50441898.36            |
| 2025-09-17 | $51229021.67              | $49938189.43            |
| 2025-09-18 | $85691856.90              | $34796804.23            |
| 2025-09-19 | $40128950.09              | $66900074.86            |
| 2025-09-22 | $38988952.54              | $53737603.35            |
| 2025-09-23 | $61139541.99              | $87409894.39            |
| 2025-09-24 | $57436652.65              | $61128502.26            |
| 2025-09-25 | $83575072.98              | $78761163.83            |
| 2025-09-26 | $57551622.84              | $80197878.06            |
| 2025-09-29 | $77002855.56              | $64404812.86            |
| 2025-09-30 | $51078040.36              | $61725588.01            |

**Total Gross Subscriptions (Month):** $1284281319.03

**Total Gross Redemptions (Month):** $1264821038.19

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-09-02 | 4.1300%           |
| 2025-09-03 | 4.1200%           |
| 2025-09-04 | 4.1200%           |
| 2025-09-05 | 4.1000%           |
| 2025-09-08 | 4.1000%           |
| 2025-09-09 | 4.0900%           |
| 2025-09-10 | 4.0900%           |
| 2025-09-11 | 4.0800%           |
| 2025-09-12 | 4.0700%           |
| 2025-09-15 | 4.0600%           |
| 2025-09-16 | 4.0600%           |
| 2025-09-17 | 4.0600%           |
| 2025-09-18 | 4.0500%           |
| 2025-09-19 | 4.0300%           |
| 2025-09-22 | 4.0300%           |
| 2025-09-23 | 4.0200%           |
| 2025-09-24 | 4.0200%           |
| 2025-09-25 | 4.0200%           |
| 2025-09-26 | 4.0000%           |
| 2025-09-29 | 4.0000%           |
| 2025-09-30 | 4.0000%           |

## 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):** $7021900618.02
- **C.18.a - Value (excl. sponsor support):** $7021900618.02
- **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