# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001145549-25-038881
**Filing Date:** 2025-6
**Character Count:** 13488
**Document Hash:** 5baf4544681baaa83f335abb9e6cf602
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001145549-25-038881.hdr.sgml**: 20250606

**ACCESSION NUMBER**: 0001145549-25-038881

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20250531

**FILED AS OF DATE**: 20250606

**DATE AS OF CHANGE**: 20250606

**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:** 251029849

**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 Prime Reserves Fund (Series ID: S000052306)

| Class ID   | Class Name              | Ticker Symbol   |
|:---|:---|:---|
| C000164452 | UBS Prime Reserves Fund | UPRXX           |

# 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):** 2025-05-31

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

**Name of Series:** UBS Prime Reserves Fund

**LEI of Series:** 549300SZFUYVRC9F4568

**EDGAR Series Identifier:** S000052306

**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:** Prime

- **Is this a Retail Money Market Fund?:** Yes

- **Is this a Government Money Market Fund?:** No

- **WAM:** 1 days

- **WAL:** 1 days

- **Total Value of Portfolio Securities:** $14659203745.57

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

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $55953477.58

- **Net Assets of Series:** $14603250267.99

- **Number of Shares Outstanding (Series):** 14602401469.0400

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2025-05-01 | $10428582626.77           | $12878257483.97            | 41.6800%                  | 51.4700%                   |
| 2025-05-02 | $9907107797.12            | $13126432342.72            | 39.5500%                  | 52.4000%                   |
| 2025-05-05 | $10306338100.56           | $13081534617.06            | 41.1900%                  | 52.2800%                   |
| 2025-05-06 | $11334169870.44           | $13057910782.56            | 45.0500%                  | 51.9000%                   |
| 2025-05-07 | $10866447191.47           | $13074890259.28            | 43.1500%                  | 51.9200%                   |
| 2025-05-08 | $10939255464.72           | $12919506940.60            | 43.5300%                  | 51.4100%                   |
| 2025-05-09 | $10415455036.22           | $12911416648.70            | 41.4000%                  | 51.3200%                   |
| 2025-05-12 | $10269333579.90           | $12992208429.80            | 40.8600%                  | 51.7000%                   |
| 2025-05-13 | $10215255087.51           | $13054740640.61            | 40.5100%                  | 51.7700%                   |
| 2025-05-14 | $9374059212.21            | $13018543567.07            | 37.1200%                  | 51.5500%                   |
| 2025-05-15 | $10108306745.74           | $13098268846.19            | 39.9000%                  | 51.7100%                   |
| 2025-05-16 | $9979734664.45            | $13475433106.19            | 38.8700%                  | 52.4800%                   |
| 2025-05-19 | $10396383939.86           | $13785544063.57            | 40.3500%                  | 53.5100%                   |
| 2025-05-20 | $10943656217.53           | $13607066158.03            | 42.5900%                  | 52.9600%                   |
| 2025-05-21 | $9625141470.55            | $13808861325.95            | 37.1200%                  | 53.2500%                   |
| 2025-05-22 | $10287911077.81           | $13564097233.31            | 40.1300%                  | 52.9100%                   |
| 2025-05-23 | $11526368227.42           | $13739969451.74            | 44.6300%                  | 53.2000%                   |
| 2025-05-27 | $11495915726.59           | $13289845614.82            | 45.0300%                  | 52.0600%                   |
| 2025-05-28 | $10100266010.14           | $13201250579.42            | 39.6400%                  | 51.8200%                   |
| 2025-05-29 | $10639368232.98           | $13312024426.28            | 41.9900%                  | 52.5300%                   |
| 2025-05-30 | $10658527197.79           | $13345564578.63            | 42.1000%                  | 52.7100%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2025-05-01 | 4.4900%             |
| 2025-05-02 | 4.5000%             |
| 2025-05-05 | 4.5000%             |
| 2025-05-06 | 4.5000%             |
| 2025-05-07 | 4.4900%             |
| 2025-05-08 | 4.4900%             |
| 2025-05-09 | 4.4700%             |
| 2025-05-12 | 4.4700%             |
| 2025-05-13 | 4.4600%             |
| 2025-05-14 | 4.4600%             |
| 2025-05-15 | 4.4600%             |
| 2025-05-16 | 4.4700%             |
| 2025-05-19 | 4.4700%             |
| 2025-05-20 | 4.4700%             |
| 2025-05-21 | 4.4700%             |
| 2025-05-22 | 4.4700%             |
| 2025-05-23 | 4.4600%             |
| 2025-05-27 | 4.4600%             |
| 2025-05-28 | 4.4600%             |
| 2025-05-29 | 4.4600%             |
| 2025-05-30 | 4.4800%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2025-05-01 | 1.0000                      |
|  |  |
| 2025-05-02 | 0.9999                      |
|  |  |
| 2025-05-05 | 1.0000                      |
|  |  |
| 2025-05-06 | 1.0000                      |
|  |  |
| 2025-05-07 | 1.0000                      |
|  |  |
| 2025-05-08 | 1.0000                      |
|  |  |
| 2025-05-09 | 0.9999                      |
|  |  |
| 2025-05-12 | 1.0000                      |
|  |  |
| 2025-05-13 | 1.0000                      |
|  |  |
| 2025-05-14 | 1.0000                      |
|  |  |
| 2025-05-15 | 1.0000                      |
|  |  |
| 2025-05-16 | 0.9999                      |
|  |  |
| 2025-05-19 | 1.0000                      |
|  |  |
| 2025-05-20 | 1.0000                      |
|  |  |
| 2025-05-21 | 1.0000                      |
|  |  |
| 2025-05-22 | 1.0000                      |
|  |  |
| 2025-05-23 | 0.9999                      |
|  |  |
| 2025-05-27 | 1.0000                      |
|  |  |
| 2025-05-28 | 1.0000                      |
|  |  |
| 2025-05-29 | 1.0000                      |
|  |  |
| 2025-05-30 | 1.0000                      |
|  |  |

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

### Class: Single Class

- **Minimum Initial Investment:** $1000000.00

- **Net Assets of Class:** $14603250267.99

- **Number of Shares Outstanding:** 14602401469.0400

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2025-05-01 | 1.0000          |
|  |  |
| 2025-05-02 | 0.9999          |
|  |  |
| 2025-05-05 | 1.0000          |
|  |  |
| 2025-05-06 | 1.0000          |
|  |  |
| 2025-05-07 | 1.0000          |
|  |  |
| 2025-05-08 | 1.0000          |
|  |  |
| 2025-05-09 | 0.9999          |
|  |  |
| 2025-05-12 | 1.0000          |
|  |  |
| 2025-05-13 | 1.0000          |
|  |  |
| 2025-05-14 | 1.0000          |
|  |  |
| 2025-05-15 | 1.0000          |
|  |  |
| 2025-05-16 | 0.9999          |
|  |  |
| 2025-05-19 | 1.0000          |
|  |  |
| 2025-05-20 | 1.0000          |
|  |  |
| 2025-05-21 | 1.0000          |
|  |  |
| 2025-05-22 | 1.0000          |
|  |  |
| 2025-05-23 | 0.9999          |
|  |  |
| 2025-05-27 | 1.0000          |
|  |  |
| 2025-05-28 | 1.0000          |
|  |  |
| 2025-05-29 | 1.0000          |
|  |  |
| 2025-05-30 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2025-05-01 | $138605015.85             | $72213191.58            |
| 2025-05-02 | $86959547.36              | $43142956.34            |
| 2025-05-05 | $116593508.10             | $72540285.96            |
| 2025-05-06 | $85135530.72              | $44610937.80            |
| 2025-05-07 | $96993202.86              | $48820004.53            |
| 2025-05-08 | $68985233.86              | $58481227.18            |
| 2025-05-09 | $68074307.35              | $51897446.06            |
| 2025-05-12 | $70763935.50              | $77522033.87            |
| 2025-05-13 | $105325790.36             | $76353683.43            |
| 2025-05-14 | $91814072.41              | $50299892.29            |
| 2025-05-15 | $120621157.61             | $52005876.67            |
| 2025-05-16 | $125324479.79             | $48392024.32            |
| 2025-05-19 | $99760922.64              | $85548272.11            |
| 2025-05-20 | $121277289.43             | $65379430.20            |
| 2025-05-21 | $61881284.91              | $93848333.32            |
| 2025-05-22 | $70746945.81              | $78452294.61            |
| 2025-05-23 | $80042566.19              | $77526011.10            |
| 2025-05-27 | $59692425.99              | $117000369.24           |
| 2025-05-28 | $57695380.00              | $70801308.09            |
| 2025-05-29 | $53531317.79              | $86248365.30            |
| 2025-05-30 | $71926931.72              | $44648985.93            |

**Total Gross Subscriptions (Month):** $1851750846.25

**Total Gross Redemptions (Month):** $1415732929.93

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2025-05-01 | 4.3100%           |
| 2025-05-02 | 4.3200%           |
| 2025-05-05 | 4.3200%           |
| 2025-05-06 | 4.3200%           |
| 2025-05-07 | 4.3100%           |
| 2025-05-08 | 4.3100%           |
| 2025-05-09 | 4.2900%           |
| 2025-05-12 | 4.2900%           |
| 2025-05-13 | 4.2800%           |
| 2025-05-14 | 4.2800%           |
| 2025-05-15 | 4.2800%           |
| 2025-05-16 | 4.2900%           |
| 2025-05-19 | 4.2900%           |
| 2025-05-20 | 4.2900%           |
| 2025-05-21 | 4.2900%           |
| 2025-05-22 | 4.2900%           |
| 2025-05-23 | 4.2800%           |
| 2025-05-27 | 4.2800%           |
| 2025-05-28 | 4.2800%           |
| 2025-05-29 | 4.2800%           |
| 2025-05-30 | 4.3000%           |

## Part C: Schedule of Portfolio Securities

### Security 1: Prime CNAV Master Fund

- **C.1 - Title:** Prime CNAV Master Fund
- **C.6 - Investment Category:** Investment Company
- **Identifiers:** C.3 - CUSIP: 927XQC905, C.3 - LEI: 549300K8VKMIOPMVLW91, C.5 - Other ID: 927XQC905
- **C.18 - Value (incl. sponsor support):** $14659203745.57
- **C.18.a - Value (excl. sponsor support):** $14659203745.57
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2025-06-02
- **C.12 - Maturity Date (WAL):** 2025-06-02
- **C.13 - Final Legal Maturity Date:** 2025-06-02
- **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:** 2025-06-06

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

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

**Title of Signing Officer:** Vice President