# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-26-042917
**Filing Date:** 2026-5
**Character Count:** 13914
**Document Hash:** c8285688efade35299ada5df85bc0357
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-042917.hdr.sgml**: 20260507

**ACCESSION NUMBER**: 0001410368-26-042917

**CONFORMED SUBMISSION TYPE**: N-MFP3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260430

**FILED AS OF DATE**: 20260507

**DATE AS OF CHANGE**: 20260507

**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:** 26952688

**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 Prime Preferred Fund (Series ID: S000052307)

| Class ID   | Class Name               | Ticker Symbol   |
|:---|:---|:---|
| C000164453 | UBS Prime Preferred Fund | UPPXX           |

# 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):** 2026-04-30

**Registrant Full Name:** UBS Series Funds

**CIK Number of Registrant:** 0001060517

**LEI of Registrant:** 54930058UKPXVB81RJ71

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

**LEI of Series:** 5493001YQBD9A4ZH6D79

**EDGAR Series Identifier:** S000052307

**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:** $9092459660.98

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

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $27836257.99

- **Net Assets of Series:** $9064623402.99

- **Number of Shares Outstanding (Series):** 9063955683.4210

- **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 (%)   |
|:---|:---|:---|:---|:---|
| 2026-04-01 | $13094596616.34           | $13993063522.13            | 52.7400%                  | 56.3600%                   |
| 2026-04-02 | $13388822077.34           | $14375337093.40            | 53.7500%                  | 57.7100%                   |
| 2026-04-03 | $0.00                     | $0.00                      | 0.0000%                   | 0.0000%                    |
| 2026-04-06 | $13138280925.67           | $14210006968.32            | 53.0100%                  | 57.3300%                   |
| 2026-04-07 | $12885502321.22           | $14377111353.67            | 52.2400%                  | 58.2800%                   |
| 2026-04-08 | $12765294995.33           | $14306931494.93            | 51.4000%                  | 57.6000%                   |
| 2026-04-09 | $12472619028.20           | $13826226834.20            | 50.8700%                  | 56.3900%                   |
| 2026-04-10 | $12570196278.56           | $13643949688.06            | 51.2000%                  | 55.5800%                   |
| 2026-04-13 | $11929515380.84           | $13083056269.34            | 49.8900%                  | 54.7100%                   |
| 2026-04-14 | $11828817347.31           | $12807413152.31            | 50.0500%                  | 54.1900%                   |
| 2026-04-15 | $11725491329.81           | $12719111166.81            | 49.9300%                  | 54.1600%                   |
| 2026-04-16 | $11268800741.49           | $12477337066.99            | 47.9000%                  | 53.0400%                   |
| 2026-04-17 | $11504938786.15           | $12113737543.15            | 49.1500%                  | 51.7500%                   |
| 2026-04-20 | $11219112518.98           | $12107827879.48            | 47.9400%                  | 51.7400%                   |
| 2026-04-21 | $11257023637.89           | $12155683823.39            | 48.0800%                  | 51.9200%                   |
| 2026-04-22 | $11258596377.77           | $12042285616.77            | 48.1300%                  | 51.4800%                   |
| 2026-04-23 | $10989284472.98           | $12049924006.48            | 47.0500%                  | 51.5900%                   |
| 2026-04-24 | $11242355544.18           | $12223061182.18            | 48.1300%                  | 52.3300%                   |
| 2026-04-27 | $10948055766.51           | $12208655997.01            | 46.9500%                  | 52.3600%                   |
| 2026-04-28 | $10969327458.35           | $12428033109.87            | 47.1000%                  | 53.3600%                   |
| 2026-04-29 | $11113866247.47           | $12423591320.05            | 47.6800%                  | 53.3000%                   |
| 2026-04-30 | $11022755275.42           | $12260463919.74            | 47.2800%                  | 52.5800%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2026-04-01 | 3.7900%             |
| 2026-04-02 | 3.7900%             |
| 2026-04-03 | 0.0000%             |
| 2026-04-06 | 3.7900%             |
| 2026-04-07 | 3.7800%             |
| 2026-04-08 | 3.7800%             |
| 2026-04-09 | 3.7800%             |
| 2026-04-10 | 3.7700%             |
| 2026-04-13 | 3.7700%             |
| 2026-04-14 | 3.7700%             |
| 2026-04-15 | 3.7800%             |
| 2026-04-16 | 3.7800%             |
| 2026-04-17 | 3.8000%             |
| 2026-04-20 | 3.8100%             |
| 2026-04-21 | 3.8100%             |
| 2026-04-22 | 3.8000%             |
| 2026-04-23 | 3.8000%             |
| 2026-04-24 | 3.8100%             |
| 2026-04-27 | 3.8100%             |
| 2026-04-28 | 3.8100%             |
| 2026-04-29 | 3.8100%             |
| 2026-04-30 | 3.8100%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2026-04-01 | 1.0000                      |
|  |  |
| 2026-04-02 | 0.9999                      |
|  |  |
| 2026-04-03 | 0.0000                      |
|  |  |
| 2026-04-06 | 1.0000                      |
|  |  |
| 2026-04-07 | 1.0000                      |
|  |  |
| 2026-04-08 | 1.0000                      |
|  |  |
| 2026-04-09 | 1.0000                      |
|  |  |
| 2026-04-10 | 0.9999                      |
|  |  |
| 2026-04-13 | 1.0000                      |
|  |  |
| 2026-04-14 | 1.0000                      |
|  |  |
| 2026-04-15 | 1.0000                      |
|  |  |
| 2026-04-16 | 1.0000                      |
|  |  |
| 2026-04-17 | 0.9999                      |
|  |  |
| 2026-04-20 | 1.0000                      |
|  |  |
| 2026-04-21 | 1.0000                      |
|  |  |
| 2026-04-22 | 1.0000                      |
|  |  |
| 2026-04-23 | 1.0000                      |
|  |  |
| 2026-04-24 | 0.9999                      |
|  |  |
| 2026-04-27 | 1.0000                      |
|  |  |
| 2026-04-28 | 1.0000                      |
|  |  |
| 2026-04-29 | 1.0000                      |
|  |  |
| 2026-04-30 | 1.0000                      |
|  |  |

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

### Class: Single Class

- **Minimum Initial Investment:** $50000000.00

- **Net Assets of Class:** $9064623402.99

- **Number of Shares Outstanding:** 9063955683.4210

- **Expense Reimbursement/Waiver:** 307074.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-04-01 | 1.0000          |
|  |  |
| 2026-04-02 | 0.9999          |
|  |  |
| 2026-04-03 | 0.0000          |
|  |  |
| 2026-04-06 | 1.0000          |
|  |  |
| 2026-04-07 | 1.0000          |
|  |  |
| 2026-04-08 | 1.0000          |
|  |  |
| 2026-04-09 | 1.0000          |
|  |  |
| 2026-04-10 | 0.9999          |
|  |  |
| 2026-04-13 | 1.0000          |
|  |  |
| 2026-04-14 | 1.0000          |
|  |  |
| 2026-04-15 | 1.0000          |
|  |  |
| 2026-04-16 | 1.0000          |
|  |  |
| 2026-04-17 | 0.9999          |
|  |  |
| 2026-04-20 | 1.0000          |
|  |  |
| 2026-04-21 | 1.0000          |
|  |  |
| 2026-04-22 | 1.0000          |
|  |  |
| 2026-04-23 | 1.0000          |
|  |  |
| 2026-04-24 | 0.9999          |
|  |  |
| 2026-04-27 | 1.0000          |
|  |  |
| 2026-04-28 | 1.0000          |
|  |  |
| 2026-04-29 | 1.0000          |
|  |  |
| 2026-04-30 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-04-01 | $93132939.17              | $51748108.42            |
| 2026-04-02 | $84548739.61              | $54494952.72            |
| 2026-04-03 | $0.00                     | $0.00                   |
| 2026-04-06 | $53579410.78              | $120937879.50           |
| 2026-04-07 | $39339755.86              | $157741588.97           |
| 2026-04-08 | $54779559.87              | $84611732.36            |
| 2026-04-09 | $45001849.84              | $65199536.47            |
| 2026-04-10 | $50666399.01              | $139806096.07           |
| 2026-04-13 | $31567842.25              | $298761695.90           |
| 2026-04-14 | $33134573.30              | $149325179.63           |
| 2026-04-15 | $44832019.07              | $105771766.13           |
| 2026-04-16 | $42694625.85              | $99299790.29            |
| 2026-04-17 | $48240718.09              | $54084619.26            |
| 2026-04-20 | $53164701.76              | $46587755.31            |
| 2026-04-21 | $79901858.65              | $63499258.37            |
| 2026-04-22 | $45848937.67              | $69845741.26            |
| 2026-04-23 | $37163706.40              | $51999582.17            |
| 2026-04-24 | $34642746.81              | $45425921.90            |
| 2026-04-27 | $35396298.66              | $50561077.29            |
| 2026-04-28 | $54193074.61              | $56212467.27            |
| 2026-04-29 | $51319457.61              | $63713958.91            |
| 2026-04-30 | $121278011.20             | $57204404.65            |

**Total Gross Subscriptions (Month):** $1134427226.07

**Total Gross Redemptions (Month):** $1886833112.85

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-04-01 | 3.6500%           |
| 2026-04-02 | 3.6500%           |
| 2026-04-03 | 0.0000%           |
| 2026-04-06 | 3.6400%           |
| 2026-04-07 | 3.6400%           |
| 2026-04-08 | 3.6400%           |
| 2026-04-09 | 3.6400%           |
| 2026-04-10 | 3.6300%           |
| 2026-04-13 | 3.6300%           |
| 2026-04-14 | 3.6300%           |
| 2026-04-15 | 3.6400%           |
| 2026-04-16 | 3.6400%           |
| 2026-04-17 | 3.6600%           |
| 2026-04-20 | 3.6700%           |
| 2026-04-21 | 3.6700%           |
| 2026-04-22 | 3.6600%           |
| 2026-04-23 | 3.6600%           |
| 2026-04-24 | 3.6700%           |
| 2026-04-27 | 3.6700%           |
| 2026-04-28 | 3.6700%           |
| 2026-04-29 | 3.6700%           |
| 2026-04-30 | 3.6700%           |

## 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):** $9092459660.98
- **C.18.a - Value (excl. sponsor support):** $9092459660.98
- **C.19 - Percentage of Net Assets:** 100.0000%
- **C.17 - Yield as of Reporting Date:** 0.0000%
- **C.11 - Maturity Date (WAM):** 2026-05-01
- **C.12 - Maturity Date (WAL):** 2026-05-01
- **C.13 - Final Legal Maturity Date:** 2026-05-01
- **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:** 2026-05-07

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

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

**Title of Signing Officer:** Vice President