# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-26-010503
**Filing Date:** 2026-2
**Character Count:** 16966
**Document Hash:** 3d921dab6502eeb2a5c3e12e30a8eabb
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-010503.hdr.sgml**: 20260206

**ACCESSION NUMBER**: 0001410368-26-010503

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260131

**FILED AS OF DATE**: 20260206

**DATE AS OF CHANGE**: 20260206

**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:** 26607343

**BUSINESS ADDRESS:**
- **STREET 1:** C/O UBS ASSET MANAGEMENT (AMERICAS) LLC
- **STREET 2:** 1285 AVENUE OF THE AMERICAS
- **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:** 1285 AVENUE OF THE AMERICAS
- **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):** 2026-01-31

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

**Name of Series:** UBS Select 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:** $9477480713.58

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

- **Cash:** $0.00

- **Total Other Assets:** $50823.83

- **Total Liabilities:** $29325632.70

- **Net Assets of Series:** $9448205904.71

- **Number of Shares Outstanding (Series):** 9448059046.9900

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2026-01-02 | $17009605893.01           | $17009605893.01            | 99.8800%                  | 99.8800%                   |
| 2026-01-05 | $17243806274.68           | $17243806274.68            | 99.8800%                  | 99.8800%                   |
| 2026-01-06 | $17042264868.74           | $17042264868.74            | 99.8800%                  | 99.8800%                   |
| 2026-01-07 | $17169045624.64           | $17169045624.64            | 99.8900%                  | 99.8900%                   |
| 2026-01-08 | $17161306762.89           | $17161306762.89            | 99.8900%                  | 99.8900%                   |
| 2026-01-09 | $17274766549.89           | $17274766549.89            | 99.8800%                  | 99.8800%                   |
| 2026-01-12 | $17617354880.51           | $17617354880.51            | 99.8800%                  | 99.8800%                   |
| 2026-01-13 | $17108097656.57           | $17108097656.57            | 99.8800%                  | 99.8800%                   |
| 2026-01-14 | $17225499515.76           | $17225499515.76            | 99.8800%                  | 99.8800%                   |
| 2026-01-15 | $17161614954.01           | $17161614954.01            | 99.8800%                  | 99.8800%                   |
| 2026-01-16 | $17257226484.14           | $17257226484.14            | 99.8800%                  | 99.8800%                   |
| 2026-01-20 | $17209566844.12           | $17209566844.12            | 99.8900%                  | 99.8900%                   |
| 2026-01-21 | $17484514691.81           | $17484514691.81            | 99.8900%                  | 99.8900%                   |
| 2026-01-22 | $17375463914.26           | $17375463914.26            | 99.8800%                  | 99.8800%                   |
| 2026-01-23 | $17415361104.11           | $17415361104.11            | 99.8800%                  | 99.8800%                   |
| 2026-01-26 | $17962838131.85           | $17962838131.85            | 99.8900%                  | 99.8900%                   |
| 2026-01-27 | $17313555213.48           | $17313555213.48            | 99.8900%                  | 99.8900%                   |
| 2026-01-28 | $17443506485.80           | $17443506485.80            | 99.8900%                  | 99.8900%                   |
| 2026-01-29 | $17809804638.49           | $17809804638.49            | 99.8900%                  | 99.8900%                   |
| 2026-01-30 | $17824943973.37           | $17824943973.37            | 99.8900%                  | 99.8900%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2026-01-02 | 3.7900%             |
| 2026-01-05 | 3.7900%             |
| 2026-01-06 | 3.7800%             |
| 2026-01-07 | 3.7800%             |
| 2026-01-08 | 3.7700%             |
| 2026-01-09 | 3.7600%             |
| 2026-01-12 | 3.7500%             |
| 2026-01-13 | 3.7500%             |
| 2026-01-14 | 3.7500%             |
| 2026-01-15 | 3.7500%             |
| 2026-01-16 | 3.7400%             |
| 2026-01-20 | 3.7400%             |
| 2026-01-21 | 3.7300%             |
| 2026-01-22 | 3.7300%             |
| 2026-01-23 | 3.7300%             |
| 2026-01-26 | 3.7200%             |
| 2026-01-27 | 3.7200%             |
| 2026-01-28 | 3.7200%             |
| 2026-01-29 | 3.7200%             |
| 2026-01-30 | 3.7100%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2026-01-02 | 1.0002                      |
|  |  |
| 2026-01-05 | 1.0002                      |
|  |  |
| 2026-01-06 | 1.0002                      |
|  |  |
| 2026-01-07 | 1.0002                      |
|  |  |
| 2026-01-08 | 1.0002                      |
|  |  |
| 2026-01-09 | 1.0002                      |
|  |  |
| 2026-01-12 | 1.0001                      |
|  |  |
| 2026-01-13 | 1.0001                      |
|  |  |
| 2026-01-14 | 1.0001                      |
|  |  |
| 2026-01-15 | 1.0001                      |
|  |  |
| 2026-01-16 | 1.0001                      |
|  |  |
| 2026-01-20 | 1.0001                      |
|  |  |
| 2026-01-21 | 1.0001                      |
|  |  |
| 2026-01-22 | 1.0001                      |
|  |  |
| 2026-01-23 | 1.0001                      |
|  |  |
| 2026-01-26 | 1.0001                      |
|  |  |
| 2026-01-27 | 1.0001                      |
|  |  |
| 2026-01-28 | 1.0001                      |
|  |  |
| 2026-01-29 | 1.0001                      |
|  |  |
| 2026-01-30 | 1.0001                      |
|  |  |

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

### Class: Class P

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $494864754.41

- **Number of Shares Outstanding:** 494854612.3800

- **Expense Reimbursement/Waiver:** 20141.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-01-02 | 1.0002          |
|  |  |
| 2026-01-05 | 1.0002          |
|  |  |
| 2026-01-06 | 1.0002          |
|  |  |
| 2026-01-07 | 1.0002          |
|  |  |
| 2026-01-08 | 1.0002          |
|  |  |
| 2026-01-09 | 1.0002          |
|  |  |
| 2026-01-12 | 1.0002          |
|  |  |
| 2026-01-13 | 1.0002          |
|  |  |
| 2026-01-14 | 1.0001          |
|  |  |
| 2026-01-15 | 1.0001          |
|  |  |
| 2026-01-16 | 1.0001          |
|  |  |
| 2026-01-20 | 1.0001          |
|  |  |
| 2026-01-21 | 1.0001          |
|  |  |
| 2026-01-22 | 1.0001          |
|  |  |
| 2026-01-23 | 1.0001          |
|  |  |
| 2026-01-26 | 1.0001          |
|  |  |
| 2026-01-27 | 1.0001          |
|  |  |
| 2026-01-28 | 1.0001          |
|  |  |
| 2026-01-29 | 1.0001          |
|  |  |
| 2026-01-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-01-02 | $17074040.49              | $2283393.68             |
| 2026-01-05 | $6364620.29               | $3930193.28             |
| 2026-01-06 | $12810413.88              | $4799893.39             |
| 2026-01-07 | $3990944.04               | $4118060.28             |
| 2026-01-08 | $9006615.35               | $7861144.24             |
| 2026-01-09 | $5577408.81               | $6941087.79             |
| 2026-01-12 | $3902703.89               | $11755458.90            |
| 2026-01-13 | $1460835.79               | $13265922.25            |
| 2026-01-14 | $12806071.67              | $26900193.58            |
| 2026-01-15 | $2624353.32               | $5507257.68             |
| 2026-01-16 | $21391335.54              | $9240329.34             |
| 2026-01-20 | $5248117.51               | $9918516.28             |
| 2026-01-21 | $1726706.13               | $13549291.89            |
| 2026-01-22 | $12048537.43              | $9935709.96             |
| 2026-01-23 | $35482063.19              | $8535681.85             |
| 2026-01-26 | $1373575.08               | $9063738.92             |
| 2026-01-27 | $5001297.68               | $5972166.68             |
| 2026-01-28 | $1981789.23               | $4799930.73             |
| 2026-01-29 | $904414.91                | $5649361.99             |
| 2026-01-30 | $7144659.46               | $4422190.48             |

**Total Gross Subscriptions (Month):** $167920503.69

**Total Gross Redemptions (Month):** $168449523.19

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-01-02 | 3.6500%           |
| 2026-01-05 | 3.6500%           |
| 2026-01-06 | 3.6400%           |
| 2026-01-07 | 3.6400%           |
| 2026-01-08 | 3.6300%           |
| 2026-01-09 | 3.6200%           |
| 2026-01-12 | 3.6100%           |
| 2026-01-13 | 3.6100%           |
| 2026-01-14 | 3.6100%           |
| 2026-01-15 | 3.6100%           |
| 2026-01-16 | 3.6000%           |
| 2026-01-20 | 3.6000%           |
| 2026-01-21 | 3.5900%           |
| 2026-01-22 | 3.5900%           |
| 2026-01-23 | 3.5900%           |
| 2026-01-26 | 3.5800%           |
| 2026-01-27 | 3.5800%           |
| 2026-01-28 | 3.5800%           |
| 2026-01-29 | 3.5800%           |
| 2026-01-30 | 3.5700%           |

**Beneficial/Record Owner Categories**
| Category        | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Retail investor |  | 6.1900%          | 0.0000%              |

### Class: Class T

- **Minimum Initial Investment:** $5000000.00

- **Net Assets of Class:** $8953341150.30

- **Number of Shares Outstanding:** 8953204434.6100

- **Expense Reimbursement/Waiver:** 334685.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-01-02 | 1.0002          |
|  |  |
| 2026-01-05 | 1.0002          |
|  |  |
| 2026-01-06 | 1.0002          |
|  |  |
| 2026-01-07 | 1.0002          |
|  |  |
| 2026-01-08 | 1.0002          |
|  |  |
| 2026-01-09 | 1.0002          |
|  |  |
| 2026-01-12 | 1.0001          |
|  |  |
| 2026-01-13 | 1.0001          |
|  |  |
| 2026-01-14 | 1.0001          |
|  |  |
| 2026-01-15 | 1.0001          |
|  |  |
| 2026-01-16 | 1.0001          |
|  |  |
| 2026-01-20 | 1.0001          |
|  |  |
| 2026-01-21 | 1.0001          |
|  |  |
| 2026-01-22 | 1.0001          |
|  |  |
| 2026-01-23 | 1.0001          |
|  |  |
| 2026-01-26 | 1.0001          |
|  |  |
| 2026-01-27 | 1.0001          |
|  |  |
| 2026-01-28 | 1.0001          |
|  |  |
| 2026-01-29 | 1.0001          |
|  |  |
| 2026-01-30 | 1.0001          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-01-02 | $45637860.45              | $19344705.55            |
| 2026-01-05 | $17474321.66              | $12488381.92            |
| 2026-01-06 | $98146490.55              | $25727563.67            |
| 2026-01-07 | $12041384.84              | $15634682.43            |
| 2026-01-08 | $103799788.47             | $94112884.86            |
| 2026-01-09 | $16591926.57              | $8424493.26             |
| 2026-01-12 | $227726218.78             | $35432870.91            |
| 2026-01-13 | $11872594.04              | $290399479.61           |
| 2026-01-14 | $28643827.49              | $20609469.33            |
| 2026-01-15 | $17308985.84              | $41802888.50            |
| 2026-01-16 | $3412127.48               | $17226000.33            |
| 2026-01-20 | $143809571.52             | $13379411.38            |
| 2026-01-21 | $12926891.16              | $59837315.98            |
| 2026-01-22 | $53960482.77              | $14671041.80            |
| 2026-01-23 | $18723651.23              | $40958233.61            |
| 2026-01-26 | $21414633.65              | $18493821.44            |
| 2026-01-27 | $32129263.02              | $33942620.40            |
| 2026-01-28 | $14731506.86              | $16385792.94            |
| 2026-01-29 | $495755346.05             | $70310192.90            |
| 2026-01-30 | $25616639.33              | $65373400.34            |

**Total Gross Subscriptions (Month):** $1401723511.76

**Total Gross Redemptions (Month):** $914555251.16

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-01-02 | 3.6500%           |
| 2026-01-05 | 3.6500%           |
| 2026-01-06 | 3.6400%           |
| 2026-01-07 | 3.6400%           |
| 2026-01-08 | 3.6300%           |
| 2026-01-09 | 3.6200%           |
| 2026-01-12 | 3.6100%           |
| 2026-01-13 | 3.6100%           |
| 2026-01-14 | 3.6100%           |
| 2026-01-15 | 3.6100%           |
| 2026-01-16 | 3.6000%           |
| 2026-01-20 | 3.6000%           |
| 2026-01-21 | 3.5900%           |
| 2026-01-22 | 3.5900%           |
| 2026-01-23 | 3.5900%           |
| 2026-01-26 | 3.5800%           |
| 2026-01-27 | 3.5800%           |
| 2026-01-28 | 3.5800%           |
| 2026-01-29 | 3.5800%           |
| 2026-01-30 | 3.5700%           |

## 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: 5299000M97HC3J8TJ387
- **C.18 - Value (incl. sponsor support):** $9477480713.58
- **C.18.a - Value (excl. sponsor support):** $9477480713.58
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2026-02-02
- **C.12 - Maturity Date (WAL):** 2026-02-02
- **C.13 - Final Legal Maturity Date:** 2026-02-02
- **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:** 2026-02-06

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

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

**Title of Signing Officer:** Vice President