# EDGAR Filing Document

**Accession Number:** 0000831114
**File Stem:** 0001398344-25-023168
**Filing Date:** 2025-12
**Character Count:** 12169
**Document Hash:** 52f8f386d38844b6f8e903080b623c7d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001398344-25-023168.hdr.sgml**: 20251231

**ACCESSION NUMBER**: 0001398344-25-023168

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 15

**FILED AS OF DATE**: 20251231

**DATE AS OF CHANGE**: 20251231

**EFFECTIVENESS DATE**: 20251231

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** RBB FUND, INC.
- **CENTRAL INDEX KEY:** 0000831114

**ORGANIZATION NAME:**
- **EIN:** 510312196
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 0831

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-20827
- **FILM NUMBER:** 251615875

**BUSINESS ADDRESS:**
- **STREET 1:** 615 E. MICHIGAN ST.
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53202
- **BUSINESS PHONE:** 609-731-6256

**MAIL ADDRESS:**
- **STREET 1:** 615 E. MICHIGAN ST.
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53202

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** RBB FUND INC
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** FUND INC /DE/
- **DATE OF NAME CHANGE:** 19600201

## Series and Classes Contracts Data

### Boston Partners Small Cap Value Fund II (Series ID: S000001094)

---

|  |  |  |
|:---|:---|:---|
| Class Name    | Ticker Symbol | Class ID   |
| INSTITUTIONAL | BPSIX         | C000002982 |
| INVESTOR      | BPSCX         | C000002983 |

---

### WPG Partners Small Cap Value Diversified Fund (Series ID: S000001097)

---

|  |  |  |
|:---|:---|:---|
| Class Name    | Ticker Symbol | Class ID   |
| INSTITUTIONAL | WPGTX         | C000002987 |

---

### Boston Partners All-Cap Value Fund (Series ID: S000001106)

---

|  |  |  |
|:---|:---|:---|
| Class Name    | Ticker Symbol | Class ID   |
| INSTITUTIONAL | BPAIX         | C000002997 |
| INVESTOR      | BPAVX         | C000002998 |

---

### Boston Partners Long/Short Equity Fund (Series ID: S000001108)

---

|  |  |  |
|:---|:---|:---|
| Class Name    | Ticker Symbol | Class ID   |
| INSTITUTIONAL | BPLSX         | C000003001 |
| INVESTOR      | BPLEX         | C000003002 |

---

### Boston Partners Long/Short Research Fund (Series ID: S000030191)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Investor Class      | BPRRX         | C000092912 |
| Institutional Class | BPIRX         | C000092913 |

---

### Boston Partners Global Equity Fund (Series ID: S000035438)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Institutional Class | BPGIX         | C000108834 |

---

### Boston Partners Global Sustainability Fund (Series ID: S000074882)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Institutional Class | BPGSX         | C000233241 |

---

### WPG Partners Select Small Cap Value Fund (Series ID: S000074886)

---

|  |  |  |
|:---|:---|:---|
| Class Name          | Ticker Symbol | Class ID   |
| Institutional Class | WPGSX         | C000233246 |

---

## Series and Classes Contracts Data

### Boston Partners Small Cap Value Fund II (Series ID: S000001094)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000002982 | INSTITUTIONAL | BPSIX           |
| C000002983 | INVESTOR      | BPSCX           |

### WPG Partners Small Cap Value Diversified Fund (Series ID: S000001097)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000002987 | INSTITUTIONAL | WPGTX           |

### Boston Partners All-Cap Value Fund (Series ID: S000001106)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000002997 | INSTITUTIONAL | BPAIX           |
| C000002998 | INVESTOR      | BPAVX           |

### Boston Partners Long/Short Equity Fund (Series ID: S000001108)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000003001 | INSTITUTIONAL | BPLSX           |
| C000003002 | INVESTOR      | BPLEX           |

### Boston Partners Long/Short Research Fund (Series ID: S000030191)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000092912 | Investor Class      | BPRRX           |
| C000092913 | Institutional Class | BPIRX           |

### Boston Partners Global Equity Fund (Series ID: S000035438)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000108834 | Institutional Class | BPGIX           |

### Boston Partners Global Sustainability Fund (Series ID: S000074882)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000233241 | Institutional Class | BPGSX           |

### WPG Partners Select Small Cap Value Fund (Series ID: S000074886)

| Class ID   | Class Name          | Ticker Symbol   |
|:---|:---|:---|
| C000233246 | Institutional Class | WPGSX           |

?xml version='1.0' encoding='ASCII'?

**THE RBB FUND, INC.**

**Boston Partners All-Cap Value Fund**

**Boston Partners Global Equity Fund**

**Boston Partners Global Sustainability Fund**

**Boston Partners Long/Short Equity Fund**

**Boston Partners Long/Short Research Fund**

**Boston Partners Small Cap Value Fund II**

**WPG Partners Select Small Cap Value Fund**

**WPG Partners Small Cap Value Diversified Fund**

**(collectively, the "Funds")**

______________________________________________________________________________

**Supplement dated December 31, 2025**

**to the Prospectus and Statement of Additional Information ("SAI") dated December 31, 2025**

______________________________________________________________________________

Effective March 2, 2026, the disclosures describing the investment objectives of the Funds in the Prospectus and SAI are updated as follows:

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – BOSTON PARTNERS ALL-CAP VALUE FUND**" of the Prospectus is superseded and replaced with the following:

The Boston Partners All-Cap Value Fund (the "Fund") seeks long-term growth of capital and outperformance of its benchmark net of fees.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – BOSTON PARTNERS GLOBAL EQUITY FUND**" of the Prospectus is superseded and replaced with the following:

The Boston Partners Global Equity Fund (the "Fund") seeks long-term growth of capital and outperformance of its benchmark net of fees.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – BOSTON PARTNERS GLOBAL SUSTAINABILITY FUND**" of the Prospectus is superseded and replaced with the following:

The Boston Partners Global Sustainability Fund (the "Fund") seeks long-term growth of capital and outperformance of its benchmark net of fees.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – BOSTON PARTNERS LONG/SHORT EQUITY FUND**" of the Prospectus is superseded and replaced with the following:

The Boston Partners Long/Short Equity Fund (the "Fund") seeks long-term growth of capital with reduced exposure to general equity market risk.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – BOSTON PARTNERS LONG/SHORT RESEARCH FUND**" of the Prospectus is superseded and replaced with the following:

The Boston Partners Long/Short Research Fund (the "Fund") seeks long-term growth of capital with reduced exposure to general equity market risk.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – BOSTON PARTNERS SMALL CAP VALUE FUND II**" of the Prospectus is superseded and replaced with the following:

The Boston Partners Small Cap Value Fund II (the "Fund") seeks long-term growth of capital and outperformance of its benchmark net of fees.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – WPG PARTNERS SELECT SMALL CAP VALUE FUND**" of the Prospectus is superseded and replaced with the following:

The WPG Partners Select Small Cap Value Fund (the "Fund") seeks long-term growth of capital and outperformance of its benchmark net of fees.

The section entitled "**Investment Objective**" under the "**SUMMARY SECTION – WPG PARTNERS SMALL CAP VALUE DIVERSIFIED FUND**" of the Prospectus is superseded and replaced with the following:

The WPG Partners Small Cap Value Diversified Fund (the "Fund") seeks long-term growth of capital and outperformance of its benchmark net of fees.

The section entitled "**Investment Objectives**" under the "**ADDITIONAL INFORMATION ABOUT THE FUNDS' INVESTMENTS AND RISKS**" section of the Prospectus is superseded and replaced with the following:

**Boston Partners All-Cap Value Fund**

Boston Partners All-Cap Value Fund seeks long-term growth of capital and outperformance of its benchmark net of fees.

**Boston Partners Global Equity Fund**

Boston Partners Global Equity Fund seeks long-term growth of capital and outperformance of its benchmark net of fees.

**Boston Partners Global Sustainability Fund**

Boston Partners Global Sustainability Fund seeks long-term growth of capital and outperformance of its benchmark net of fees.

**Boston Partners Long/Short Equity Fund**

Boston Partners Long/Short Equity Fund seeks long-term growth of capital with reduced exposure to general equity market risk.

**Boston Partners Long/Short Research Fund**

Boston Partners Long/Short Research Fund seeks long-term growth of capital with reduced exposure to general equity market risk.

**Boston Partners Small Cap Value Fund II**

Boston Partners Small Cap Value Fund II seeks long-term growth of capital and outperformance of its benchmark net of fees.

**WPG Partners Select Small Cap Value Fund**

WPG Partners Select Small Cap Value Fund seeks long-term growth of capital and outperformance of its benchmark net of fees.

**WPG Partners Small Cap Value Diversified Fund**

WPG Partners Small Cap Value Diversified Fund seeks long-term growth of capital and outperformance of its benchmark net of fees.

The Funds' investment objectives may be changed by the Board of Directors (the "Board") of the Company without shareholder approval. Shareholders will, however, receive 60 days' prior notice of any changes. Any such changes may result in the Funds having investment objectives different from the objectives that the shareholder considered appropriate at the time of investment in the Funds.

The section entitled "**PRINCIPAL INVESTMENT INSTRUMENTS AND POLICIES**" of the **SAI** is superseded and replaced with the following:

The following supplements the information contained in the Prospectuses concerning the investment objectives and policies of the Funds. To the extent an investment policy is discussed in this SAI but not in the Prospectuses, such policy is not a principal policy of the Funds. Except as indicated, the information below relates only to those Funds that are authorized to invest in the instruments or securities described below.

The **All-Cap Value Fund** seeks long-term growth of capital and outperformance of its benchmark net of fees.

The **Global Equity Fund** seeks long-term growth of capital and outperformance of its benchmark net of fees.

The **Global Sustainability Fund** seeks long-term growth of capital and outperformance of its benchmark net of fees.

The **Long/Short Equity Fund** seeks long-term growth of capital with reduced exposure to general equity market risk.

The **Long/Short Research Fund** seeks long-term growth of capital with reduced exposure to general equity market risk.

The **Small Cap Value Fund II** seeks long-term growth of capital and outperformance of its benchmark net of fees.

The **WPG Partners Select Small Cap Value Fund** seeks long-term growth of capital and outperformance of its benchmark net of fees.

The **WPG Partners Small Cap Value Diversified Fund** seeks long-term growth of capital and outperformance of its benchmark net of fees.

The Adviser may not necessarily invest in all of the instruments or use all of the investment techniques permitted by the Funds' Prospectuses and this SAI, or invest in such instruments or engage in such techniques to the full extent permitted by the Funds' investment policies and limitations.

**\* \* \* \* \***

**Please retain this supplement for your reference.**