# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-26-034971
**Filing Date:** 2026-4
**Character Count:** 17986
**Document Hash:** e4924330e10352491156476546c58f59
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-034971.hdr.sgml**: 20260407

**ACCESSION NUMBER**: 0001410368-26-034971

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260331

**FILED AS OF DATE**: 20260407

**DATE AS OF CHANGE**: 20260407

**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:** 26843751

**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 Institutional Fund (Series ID: S000084282)

| Class ID   | Class Name           | Ticker Symbol   |
|:---|:---|:---|
| C000248579 | Institutional Shares | SIOXX           |
| C000271489 | Token-Enabled Shares | TOKXX           |

# 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):** 2026-03-31

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

**Name of Series:** UBS Select 100% US Treasury Institutional Fund

**LEI of Series:** 529900KWG787B4G5P791

**EDGAR Series Identifier:** S000084282

**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:** $8023315632.02

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

- **Cash:** $0.00

- **Total Other Assets:** $63605.55

- **Total Liabilities:** $25233180.88

- **Net Assets of Series:** $7998146056.69

- **Number of Shares Outstanding (Series):** 7997948344.8800

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2026-03-02 | $17889271877.46           | $17889271877.46            | 99.9300%                  | 99.9300%                   |
| 2026-03-03 | $17780955792.49           | $17780955792.49            | 99.9300%                  | 99.9300%                   |
| 2026-03-04 | $17995676595.42           | $17995676595.42            | 99.9300%                  | 99.9300%                   |
| 2026-03-05 | $17848740399.34           | $17848740399.34            | 99.9300%                  | 99.9300%                   |
| 2026-03-06 | $17885550745.70           | $17885550745.70            | 99.9300%                  | 99.9300%                   |
| 2026-03-09 | $18113143739.31           | $18113143739.31            | 99.9300%                  | 99.9300%                   |
| 2026-03-10 | $17972151500.91           | $17972151500.91            | 99.9200%                  | 99.9200%                   |
| 2026-03-11 | $18230881957.70           | $18230881957.70            | 99.9200%                  | 99.9200%                   |
| 2026-03-12 | $18123918549.51           | $18123918549.51            | 99.9200%                  | 99.9200%                   |
| 2026-03-13 | $18356458571.25           | $18356458571.25            | 99.9200%                  | 99.9200%                   |
| 2026-03-16 | $18422221264.62           | $18422221264.62            | 99.9300%                  | 99.9300%                   |
| 2026-03-17 | $18048397611.78           | $18048397611.78            | 99.9200%                  | 99.9200%                   |
| 2026-03-18 | $18314987401.10           | $18314987401.10            | 99.9200%                  | 99.9200%                   |
| 2026-03-19 | $18231905050.66           | $18231905050.66            | 99.9200%                  | 99.9200%                   |
| 2026-03-20 | $18021921666.56           | $18021921666.56            | 99.9200%                  | 99.9200%                   |
| 2026-03-23 | $18209294953.48           | $18209294953.48            | 99.9200%                  | 99.9200%                   |
| 2026-03-24 | $17873459827.61           | $17873459827.61            | 99.9100%                  | 99.9100%                   |
| 2026-03-25 | $17979897450.59           | $17979897450.59            | 99.9100%                  | 99.9100%                   |
| 2026-03-26 | $18020509092.41           | $18020509092.41            | 99.9100%                  | 99.9100%                   |
| 2026-03-27 | $17929891424.71           | $17929891424.71            | 99.9100%                  | 99.9100%                   |
| 2026-03-30 | $18070124997.50           | $18070124997.50            | 99.9100%                  | 99.9100%                   |
| 2026-03-31 | $17783469598.92           | $17783469598.92            | 99.9200%                  | 99.9200%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2026-03-02 | 3.7000%             |
| 2026-03-03 | 3.7000%             |
| 2026-03-04 | 3.6900%             |
| 2026-03-05 | 3.6900%             |
| 2026-03-06 | 3.6900%             |
| 2026-03-09 | 3.6900%             |
| 2026-03-10 | 3.6900%             |
| 2026-03-11 | 3.6900%             |
| 2026-03-12 | 3.6900%             |
| 2026-03-13 | 3.6900%             |
| 2026-03-16 | 3.6900%             |
| 2026-03-17 | 3.6900%             |
| 2026-03-18 | 3.6900%             |
| 2026-03-19 | 3.6900%             |
| 2026-03-20 | 3.6900%             |
| 2026-03-23 | 3.6900%             |
| 2026-03-24 | 3.6900%             |
| 2026-03-25 | 3.7000%             |
| 2026-03-26 | 3.7000%             |
| 2026-03-27 | 3.7000%             |
| 2026-03-30 | 3.7000%             |
| 2026-03-31 | 3.7000%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2026-03-02 | 1.0000                      |
|  |  |
| 2026-03-03 | 1.0001                      |
|  |  |
| 2026-03-04 | 1.0000                      |
|  |  |
| 2026-03-05 | 1.0000                      |
|  |  |
| 2026-03-06 | 1.0001                      |
|  |  |
| 2026-03-09 | 1.0001                      |
|  |  |
| 2026-03-10 | 1.0000                      |
|  |  |
| 2026-03-11 | 1.0000                      |
|  |  |
| 2026-03-12 | 1.0000                      |
|  |  |
| 2026-03-13 | 1.0000                      |
|  |  |
| 2026-03-16 | 1.0000                      |
|  |  |
| 2026-03-17 | 1.0000                      |
|  |  |
| 2026-03-18 | 1.0000                      |
|  |  |
| 2026-03-19 | 1.0000                      |
|  |  |
| 2026-03-20 | 1.0000                      |
|  |  |
| 2026-03-23 | 1.0000                      |
|  |  |
| 2026-03-24 | 1.0000                      |
|  |  |
| 2026-03-25 | 1.0000                      |
|  |  |
| 2026-03-26 | 1.0000                      |
|  |  |
| 2026-03-27 | 1.0000                      |
|  |  |
| 2026-03-30 | 1.0000                      |
|  |  |
| 2026-03-31 | 1.0000                      |
|  |  |

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

### Class: Institutional

- **Minimum Initial Investment:** $1.00

- **Net Assets of Class:** $7998046056.68

- **Number of Shares Outstanding:** 7997848344.8800

- **Expense Reimbursement/Waiver:** 35448.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-03-02 | 1.0000          |
|  |  |
| 2026-03-03 | 1.0001          |
|  |  |
| 2026-03-04 | 1.0000          |
|  |  |
| 2026-03-05 | 1.0000          |
|  |  |
| 2026-03-06 | 1.0001          |
|  |  |
| 2026-03-09 | 1.0001          |
|  |  |
| 2026-03-10 | 1.0000          |
|  |  |
| 2026-03-11 | 1.0000          |
|  |  |
| 2026-03-12 | 1.0000          |
|  |  |
| 2026-03-13 | 1.0000          |
|  |  |
| 2026-03-16 | 1.0000          |
|  |  |
| 2026-03-17 | 1.0000          |
|  |  |
| 2026-03-18 | 1.0000          |
|  |  |
| 2026-03-19 | 1.0000          |
|  |  |
| 2026-03-20 | 1.0000          |
|  |  |
| 2026-03-23 | 1.0000          |
|  |  |
| 2026-03-24 | 1.0000          |
|  |  |
| 2026-03-25 | 1.0000          |
|  |  |
| 2026-03-26 | 1.0000          |
|  |  |
| 2026-03-27 | 1.0000          |
|  |  |
| 2026-03-30 | 1.0000          |
|  |  |
| 2026-03-31 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-03-02 | $73971218.56              | $56582268.83            |
| 2026-03-03 | $119826802.22             | $65930879.20            |
| 2026-03-04 | $75269550.75              | $33239907.89            |
| 2026-03-05 | $51572029.42              | $62614341.18            |
| 2026-03-06 | $76008940.02              | $40053438.08            |
| 2026-03-09 | $45096322.09              | $61411912.60            |
| 2026-03-10 | $57801595.10              | $39703314.39            |
| 2026-03-11 | $100057141.04             | $31627313.95            |
| 2026-03-12 | $29399256.07              | $53056089.81            |
| 2026-03-13 | $58763437.48              | $59532651.80            |
| 2026-03-16 | $45226253.29              | $96382838.71            |
| 2026-03-17 | $26497484.79              | $27700375.50            |
| 2026-03-18 | $64640743.13              | $65124909.76            |
| 2026-03-19 | $55675576.52              | $43859791.80            |
| 2026-03-20 | $32744393.75              | $36186257.11            |
| 2026-03-23 | $35642920.07              | $78668953.91            |
| 2026-03-24 | $20573436.77              | $61612916.66            |
| 2026-03-25 | $32531230.23              | $54103485.16            |
| 2026-03-26 | $92750456.78              | $44284461.67            |
| 2026-03-27 | $22015738.16              | $34805213.16            |
| 2026-03-30 | $44625271.09              | $71908249.69            |
| 2026-03-31 | $40596841.86              | $59350001.22            |

**Total Gross Subscriptions (Month):** $1201286639.19

**Total Gross Redemptions (Month):** $1177739572.08

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-03-02 | 3.5100%           |
| 2026-03-03 | 3.5100%           |
| 2026-03-04 | 3.5100%           |
| 2026-03-05 | 3.5100%           |
| 2026-03-06 | 3.5100%           |
| 2026-03-09 | 3.5100%           |
| 2026-03-10 | 3.5100%           |
| 2026-03-11 | 3.5100%           |
| 2026-03-12 | 3.5100%           |
| 2026-03-13 | 3.5100%           |
| 2026-03-16 | 3.5100%           |
| 2026-03-17 | 3.5100%           |
| 2026-03-18 | 3.5100%           |
| 2026-03-19 | 3.5100%           |
| 2026-03-20 | 3.5100%           |
| 2026-03-23 | 3.5100%           |
| 2026-03-24 | 3.5100%           |
| 2026-03-25 | 3.5200%           |
| 2026-03-26 | 3.5200%           |
| 2026-03-27 | 3.5200%           |
| 2026-03-30 | 3.5200%           |
| 2026-03-31 | 3.5200%           |

### Class: Token-Enabled Shares

- **Minimum Initial Investment:** $0.00

- **Net Assets of Class:** $100000.01

- **Number of Shares Outstanding:** 100000.0000

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-03-02 | 0.0000          |
|  |  |
| 2026-03-03 | 0.0000          |
|  |  |
| 2026-03-04 | 0.0000          |
|  |  |
| 2026-03-05 | 0.0000          |
|  |  |
| 2026-03-06 | 0.0000          |
|  |  |
| 2026-03-09 | 0.0000          |
|  |  |
| 2026-03-10 | 0.0000          |
|  |  |
| 2026-03-11 | 0.0000          |
|  |  |
| 2026-03-12 | 0.0000          |
|  |  |
| 2026-03-13 | 0.0000          |
|  |  |
| 2026-03-16 | 0.0000          |
|  |  |
| 2026-03-17 | 0.0000          |
|  |  |
| 2026-03-18 | 0.0000          |
|  |  |
| 2026-03-19 | 0.0000          |
|  |  |
| 2026-03-20 | 0.0000          |
|  |  |
| 2026-03-23 | 0.0000          |
|  |  |
| 2026-03-24 | 0.0000          |
|  |  |
| 2026-03-25 | 1.0000          |
|  |  |
| 2026-03-26 | 0.9999          |
|  |  |
| 2026-03-27 | 1.0000          |
|  |  |
| 2026-03-30 | 1.0000          |
|  |  |
| 2026-03-31 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-03-02 | $0.00                     | $0.00                   |
| 2026-03-03 | $0.00                     | $0.00                   |
| 2026-03-04 | $0.00                     | $0.00                   |
| 2026-03-05 | $0.00                     | $0.00                   |
| 2026-03-06 | $0.00                     | $0.00                   |
| 2026-03-09 | $0.00                     | $0.00                   |
| 2026-03-10 | $0.00                     | $0.00                   |
| 2026-03-11 | $0.00                     | $0.00                   |
| 2026-03-12 | $0.00                     | $0.00                   |
| 2026-03-13 | $0.00                     | $0.00                   |
| 2026-03-16 | $0.00                     | $0.00                   |
| 2026-03-17 | $0.00                     | $0.00                   |
| 2026-03-18 | $0.00                     | $0.00                   |
| 2026-03-19 | $0.00                     | $0.00                   |
| 2026-03-20 | $0.00                     | $0.00                   |
| 2026-03-23 | $0.00                     | $0.00                   |
| 2026-03-24 | $0.00                     | $0.00                   |
| 2026-03-25 | $100000.00                | $0.00                   |
| 2026-03-26 | $0.00                     | $0.00                   |
| 2026-03-27 | $0.00                     | $0.00                   |
| 2026-03-30 | $0.00                     | $0.00                   |
| 2026-03-31 | $0.00                     | $0.00                   |

**Total Gross Subscriptions (Month):** $100000.00

**Total Gross Redemptions (Month):** $0.00

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-03-02 | 0.0000%           |
| 2026-03-03 | 0.0000%           |
| 2026-03-04 | 0.0000%           |
| 2026-03-05 | 0.0000%           |
| 2026-03-06 | 0.0000%           |
| 2026-03-09 | 0.0000%           |
| 2026-03-10 | 0.0000%           |
| 2026-03-11 | 0.0000%           |
| 2026-03-12 | 0.0000%           |
| 2026-03-13 | 0.0000%           |
| 2026-03-16 | 0.0000%           |
| 2026-03-17 | 0.0000%           |
| 2026-03-18 | 0.0000%           |
| 2026-03-19 | 0.0000%           |
| 2026-03-20 | 0.0000%           |
| 2026-03-23 | 0.0000%           |
| 2026-03-24 | 0.0000%           |
| 2026-03-25 | 0.0000%           |
| 2026-03-26 | 0.0000%           |
| 2026-03-27 | 0.0000%           |
| 2026-03-30 | 0.0000%           |
| 2026-03-31 | 3.5200%           |

**Beneficial/Record Owner Categories**
| Category                  | Other Category   | Record Owner %   | Beneficial Owner %   |
|:---|:---|:---|:---|
| Non-financial corporation |  | 100.0000%        | 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: 5299000M97HC3J8TJ387
- **C.18 - Value (incl. sponsor support):** $8023315632.02
- **C.18.a - Value (excl. sponsor support):** $8023315632.02
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2026-04-01
- **C.12 - Maturity Date (WAL):** 2026-04-01
- **C.13 - Final Legal Maturity Date:** 2026-04-01
- **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:** 2026-04-07

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

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

**Title of Signing Officer:** Vice President