# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001410368-26-034966
**Filing Date:** 2026-4
**Character Count:** 13914
**Document Hash:** 48fe074b48a4e449bbd0e794c7567575
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001410368-26-034966.hdr.sgml**: 20260407

**ACCESSION NUMBER**: 0001410368-26-034966

**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:** 26843742

**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):** 2026-03-31

**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:** $9848302653.71

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

- **Cash:** $0.00

- **Total Other Assets:** $0.00

- **Total Liabilities:** $31228559.95

- **Net Assets of Series:** $9817074093.76

- **Number of Shares Outstanding (Series):** 9816406374.2010

- **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 | $12660090819.30           | $13541857271.50            | 50.4300%                  | 53.9400%                   |
| 2026-03-03 | $12733326928.14           | $13665065746.84            | 50.7200%                  | 54.4300%                   |
| 2026-03-04 | $12813499323.49           | $13745300102.59            | 50.8800%                  | 54.5800%                   |
| 2026-03-05 | $13292330655.51           | $13729194115.41            | 52.8100%                  | 54.5500%                   |
| 2026-03-06 | $13056545444.62           | $13755270459.12            | 51.8100%                  | 54.5900%                   |
| 2026-03-09 | $13161445296.34           | $13735320087.34            | 52.2800%                  | 54.5600%                   |
| 2026-03-10 | $13159935006.17           | $13733842514.17            | 52.2700%                  | 54.5500%                   |
| 2026-03-11 | $13268790354.73           | $13882419941.41            | 52.5900%                  | 55.0200%                   |
| 2026-03-12 | $13674172112.41           | $13947865353.81            | 54.0600%                  | 55.1400%                   |
| 2026-03-13 | $13352528365.64           | $14000017610.38            | 52.7300%                  | 55.2900%                   |
| 2026-03-16 | $13200498718.95           | $14062955545.39            | 51.8500%                  | 55.2400%                   |
| 2026-03-17 | $13293841119.45           | $14061617939.85            | 52.2200%                  | 55.2400%                   |
| 2026-03-18 | $13129588685.46           | $14047310155.56            | 51.7100%                  | 55.3200%                   |
| 2026-03-19 | $13341999839.13           | $13935783815.13            | 52.8800%                  | 55.2300%                   |
| 2026-03-20 | $13214838544.91           | $13853598771.41            | 52.4700%                  | 55.0000%                   |
| 2026-03-23 | $12955717641.81           | $13784460114.31            | 51.6900%                  | 54.9900%                   |
| 2026-03-24 | $13129732597.03           | $13808549265.53            | 52.3300%                  | 55.0300%                   |
| 2026-03-25 | $13044024996.26           | $13809860698.86            | 52.1700%                  | 55.2300%                   |
| 2026-03-26 | $13271998751.69           | $13777895709.49            | 53.1500%                  | 55.1700%                   |
| 2026-03-27 | $13315124837.21           | $14055741363.41            | 53.2500%                  | 56.2100%                   |
| 2026-03-30 | $12990056602.05           | $14100406632.30            | 52.2700%                  | 56.7300%                   |
| 2026-03-31 | $13078555105.11           | $14051994910.02            | 52.7200%                  | 56.6500%                   |

### 7-Day Gross Yield
| Date       | 7-Day Gross Yield   |
|:---|:---|
| 2026-03-02 | 3.8300%             |
| 2026-03-03 | 3.8200%             |
| 2026-03-04 | 3.8200%             |
| 2026-03-05 | 3.8200%             |
| 2026-03-06 | 3.8000%             |
| 2026-03-09 | 3.8000%             |
| 2026-03-10 | 3.7900%             |
| 2026-03-11 | 3.7900%             |
| 2026-03-12 | 3.7900%             |
| 2026-03-13 | 3.7900%             |
| 2026-03-16 | 3.7900%             |
| 2026-03-17 | 3.7900%             |
| 2026-03-18 | 3.7900%             |
| 2026-03-19 | 3.7900%             |
| 2026-03-20 | 3.7800%             |
| 2026-03-23 | 3.7800%             |
| 2026-03-24 | 3.7800%             |
| 2026-03-25 | 3.7800%             |
| 2026-03-26 | 3.7800%             |
| 2026-03-27 | 3.7900%             |
| 2026-03-30 | 3.7900%             |
| 2026-03-31 | 3.7900%             |

### Daily Net Asset Value per Share (Series)
| Date       | Net Asset Value per Share   |
|:---|:---|
| 2026-03-02 | 1.0001                      |
|  |  |
| 2026-03-03 | 1.0001                      |
|  |  |
| 2026-03-04 | 1.0001                      |
|  |  |
| 2026-03-05 | 1.0001                      |
|  |  |
| 2026-03-06 | 1.0000                      |
|  |  |
| 2026-03-09 | 1.0001                      |
|  |  |
| 2026-03-10 | 1.0001                      |
|  |  |
| 2026-03-11 | 1.0000                      |
|  |  |
| 2026-03-12 | 1.0000                      |
|  |  |
| 2026-03-13 | 0.9999                      |
|  |  |
| 2026-03-16 | 1.0000                      |
|  |  |
| 2026-03-17 | 1.0000                      |
|  |  |
| 2026-03-18 | 1.0000                      |
|  |  |
| 2026-03-19 | 1.0000                      |
|  |  |
| 2026-03-20 | 0.9999                      |
|  |  |
| 2026-03-23 | 1.0000                      |
|  |  |
| 2026-03-24 | 0.9999                      |
|  |  |
| 2026-03-25 | 0.9999                      |
|  |  |
| 2026-03-26 | 0.9999                      |
|  |  |
| 2026-03-27 | 0.9999                      |
|  |  |
| 2026-03-30 | 1.0000                      |
|  |  |
| 2026-03-31 | 1.0000                      |
|  |  |

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

### Class: Single Class

- **Minimum Initial Investment:** $50000000.00

- **Net Assets of Class:** $9817074093.76

- **Number of Shares Outstanding:** 9816406374.2010

- **Expense Reimbursement/Waiver:** 331934.00

**Daily Net Asset Value per Share (Class)**
| Date       | NAV per Share   |
|:---|:---|
| 2026-03-02 | 1.0001          |
|  |  |
| 2026-03-03 | 1.0001          |
|  |  |
| 2026-03-04 | 1.0001          |
|  |  |
| 2026-03-05 | 1.0001          |
|  |  |
| 2026-03-06 | 1.0000          |
|  |  |
| 2026-03-09 | 1.0001          |
|  |  |
| 2026-03-10 | 1.0001          |
|  |  |
| 2026-03-11 | 1.0000          |
|  |  |
| 2026-03-12 | 1.0000          |
|  |  |
| 2026-03-13 | 0.9999          |
|  |  |
| 2026-03-16 | 1.0000          |
|  |  |
| 2026-03-17 | 1.0000          |
|  |  |
| 2026-03-18 | 1.0000          |
|  |  |
| 2026-03-19 | 1.0000          |
|  |  |
| 2026-03-20 | 0.9999          |
|  |  |
| 2026-03-23 | 1.0000          |
|  |  |
| 2026-03-24 | 0.9999          |
|  |  |
| 2026-03-25 | 0.9999          |
|  |  |
| 2026-03-26 | 0.9999          |
|  |  |
| 2026-03-27 | 0.9999          |
|  |  |
| 2026-03-30 | 1.0000          |
|  |  |
| 2026-03-31 | 1.0000          |
|  |  |

**Daily Shareholder Flows**
| Date       | Gross Subscriptions ($)   | Gross Redemptions ($)   |
|:---|:---|:---|
| 2026-03-02 | $264948194.56             | $53146917.92            |
| 2026-03-03 | $63814670.78              | $59305877.89            |
| 2026-03-04 | $99824294.95              | $53462527.36            |
| 2026-03-05 | $48383350.66              | $51187999.11            |
| 2026-03-06 | $48536134.49              | $49799185.93            |
| 2026-03-09 | $32801663.40              | $49418756.51            |
| 2026-03-10 | $33006617.20              | $55930049.18            |
| 2026-03-11 | $57787800.58              | $40562571.65            |
| 2026-03-12 | $112334133.25             | $40072882.12            |
| 2026-03-13 | $61734301.88              | $51090807.63            |
| 2026-03-16 | $206186142.02             | $51000349.21            |
| 2026-03-17 | $79274138.56              | $40471900.54            |
| 2026-03-18 | $44034127.46              | $92978584.63            |
| 2026-03-19 | $47464267.80              | $184086045.55           |
| 2026-03-20 | $67733701.54              | $115831358.62           |
| 2026-03-23 | $55023089.73              | $112455017.94           |
| 2026-03-24 | $93600962.05              | $80873541.09            |
| 2026-03-25 | $41672680.31              | $114515893.15           |
| 2026-03-26 | $48680247.31              | $63735974.92            |
| 2026-03-27 | $52048515.46              | $64328469.66            |
| 2026-03-30 | $59272655.70              | $201362561.66           |
| 2026-03-31 | $36488166.17              | $60315653.07            |

**Total Gross Subscriptions (Month):** $1654649855.86

**Total Gross Redemptions (Month):** $1685932925.34

**7-Day Net Yield (Class)**
| Date       | 7-Day Net Yield   |
|:---|:---|
| 2026-03-02 | 3.6900%           |
| 2026-03-03 | 3.6800%           |
| 2026-03-04 | 3.6800%           |
| 2026-03-05 | 3.6800%           |
| 2026-03-06 | 3.6600%           |
| 2026-03-09 | 3.6600%           |
| 2026-03-10 | 3.6500%           |
| 2026-03-11 | 3.6500%           |
| 2026-03-12 | 3.6500%           |
| 2026-03-13 | 3.6500%           |
| 2026-03-16 | 3.6500%           |
| 2026-03-17 | 3.6500%           |
| 2026-03-18 | 3.6500%           |
| 2026-03-19 | 3.6500%           |
| 2026-03-20 | 3.6400%           |
| 2026-03-23 | 3.6400%           |
| 2026-03-24 | 3.6400%           |
| 2026-03-25 | 3.6400%           |
| 2026-03-26 | 3.6400%           |
| 2026-03-27 | 3.6500%           |
| 2026-03-30 | 3.6500%           |
| 2026-03-31 | 3.6500%           |

## 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):** $9848302653.71
- **C.18.a - Value (excl. sponsor support):** $9848302653.71
- **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