497

Filed Pursuant to Rule 497(e)

1933 Act File No. 033-20827

1940 Act File No. 811-05518

The RBB Fund, Inc.

Boston Partners Small Cap Value Fund II (the “Fund”)

Institutional Class (BPSIX)

Investor Class (BPSCX)

October 15, 2019

EXPLANATORY NOTE

On behalf of the Fund, a series of The RBB Fund, Inc. (the “Company”), and pursuant to Rule 497(e) under the Securities Act of 1933, as amended (the “Securities Act”), the purpose of this filing is to submit an interactive data file in the manner provided by Rule 405 of Regulation S-T and General Instruction C.3.(g) of Form N-1A.  The interactive data file included as an exhibit to this filing relates to the Supplement filed with the Securities and Exchange Commission on behalf of the Company pursuant to Rule 497(e) under the Securities Act on October 1, 2019; such form of Supplement (Accession Number 0000930413-19-002602) is incorporated by reference into this Rule 497 Document.

EXHIBIT LIST

Exhibit	Exhibit No.
Instance Document	EX-101.INS
Schema Document	EX-101.SCH
Calculation Linkbase Document	EX-101.CAL
Definition Linkbase Document	EX-101.DEF
Label Linkbase Document	EX-101.LAB
Presentation Linkbase Document	EX-101.PRE

XML

Label

Element

Value

Investor Class Prospectus | Boston Partners Small Cap Value Fund II

Risk/Return:

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Supplement to Prospectus [Text Block]

rr_SupplementToProspectusTextBlock

THE RBB FUND, INC.

Boston Partners Investment Funds

Boston Partners Small Cap Value Fund II (the “Fund”)

Investor Class (BPSCX)

Supplement dated October 1, 2019

to the Prospectus and Statement of Additional Information, each dated
December 31, 2018

Effective as of October 1, 2019, Boston Partners Global Investors, Inc., the investment adviser to the Fund (the “Adviser”), has contractually agreed to lower its investment advisory fee to 0.95% of the Fund’s average daily net assets. The Adviser has agreed to waive its advisory fee and/or reimburse expenses in order to limit Total Annual Fund Operating Expenses (excluding short sale dividend expenses, brokerage commissions, extraordinary items, interest or taxes) to 1.35% of the Fund’s average daily net assets attributable to Investor Class shares. This contractual limitation is in effect until February 28, 2021, and may not be terminated without the approval of the Board of Directors of The RBB Fund, Inc. Prior to October 1, 2019, the Fund’s management fee was 1.00%.

Accordingly, the “Expenses and Fees” table and “Example” in the section entitled “SUMMARY SECTION – Boston Partners Small Cap Value Fund II” of the Prospectus are hereby deleted and replaced with the following:

Expenses and Fees

This table describes the fees and expenses that you may pay if you buy and hold Investor Class shares of the Fund.

	Investor Class
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Management fees(1)	0.95%
Distribution and servicing (12b-1) fees	0.25%
Other expenses	0.14%
Acquired fund fees and expenses(2)	0.01%
Total annual Fund operating expenses	1.35%

(1)  Prior to October 1, 2019, the management fee was 1.00%.

(2)  Acquired fund fees and expenses are indirect fees and expenses that the Fund incurs from investing in the shares of other mutual funds, including money market funds and exchange traded funds.

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and that you sell all of your shares at the end of the period. The Example also assumes that your investment has a 5% return each year and that the operating expenses of the Fund remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year		3 Years		5 Years		10 Years
Investor Class		$138		$375		$632		$1,366

* * * * *

Please retain this supplement for your reference.

Risk/Return [Heading]

rr_RiskReturnHeading

Boston Partners Small Cap Value Fund II

XML

Document and Entity Information	Oct. 01, 2019
Prospectus:
Document Type	497
Document Period End Date	Oct. 01, 2019
Entity Registrant Name	RBB FUND, INC.
Entity Central Index Key	0000831114
Entity Inv Company Type	N-1A
Amendment Flag	false
Document Creation Date	Oct. 01, 2019
Document Effective Date	Oct. 01, 2019
Prospectus Date	Dec. 31, 2018

XML

Oct. 01, 2019

Investor Class Prospectus | Boston Partners Small Cap Value Fund II

Boston Partners Small Cap Value Fund II

THE RBB FUND, INC.

Boston Partners Investment Funds

Boston Partners Small Cap Value Fund II (the “Fund”)

Investor Class (BPSCX)

Supplement dated October 1, 2019

to the Prospectus and Statement of Additional Information, each dated
December 31, 2018

Effective as of October 1, 2019, Boston Partners Global Investors, Inc., the investment adviser to the Fund (the “Adviser”), has contractually agreed to lower its investment advisory fee to 0.95% of the Fund’s average daily net assets. The Adviser has agreed to waive its advisory fee and/or reimburse expenses in order to limit Total Annual Fund Operating Expenses (excluding short sale dividend expenses, brokerage commissions, extraordinary items, interest or taxes) to 1.35% of the Fund’s average daily net assets attributable to Investor Class shares. This contractual limitation is in effect until February 28, 2021, and may not be terminated without the approval of the Board of Directors of The RBB Fund, Inc. Prior to October 1, 2019, the Fund’s management fee was 1.00%.

Accordingly, the “Expenses and Fees” table and “Example” in the section entitled “SUMMARY SECTION – Boston Partners Small Cap Value Fund II” of the Prospectus are hereby deleted and replaced with the following:

Expenses and Fees

This table describes the fees and expenses that you may pay if you buy and hold Investor Class shares of the Fund.

	Investor Class
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Management fees(1)	0.95%
Distribution and servicing (12b-1) fees	0.25%
Other expenses	0.14%
Acquired fund fees and expenses(2)	0.01%
Total annual Fund operating expenses	1.35%

(1)  Prior to October 1, 2019, the management fee was 1.00%.

(2)  Acquired fund fees and expenses are indirect fees and expenses that the Fund incurs from investing in the shares of other mutual funds, including money market funds and exchange traded funds.

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and that you sell all of your shares at the end of the period. The Example also assumes that your investment has a 5% return each year and that the operating expenses of the Fund remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year		3 Years		5 Years		10 Years
Investor Class		$138		$375		$632		$1,366

* * * * *

Please retain this supplement for your reference.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Dec. 31, 2018

XML

Oct. 01, 2019

Institutional Class Prospectus | Boston Partners Small Cap Value Fund II

Boston Partners Small Cap Value Fund II

THE RBB FUND, INC.

Boston Partners Investment Funds

Boston Partners Small Cap Value Fund II (the “Fund”)

Institutional Class (BPSIX)

Supplement dated October 1, 2019

to the Prospectus and Statement of Additional Information, each dated
December 31, 2018

Effective as of October 1, 2019, Boston Partners Global Investors, Inc., the investment adviser to the Fund (the “Adviser”), has contractually agreed to lower its investment advisory fee to 0.95% of the Fund’s average daily net assets. The Adviser has agreed to waive its advisory fee and/or reimburse expenses in order to limit Total Annual Fund Operating Expenses (excluding short sale dividend expenses, brokerage commissions, extraordinary items, interest or taxes) to 1.10% of the Fund’s average daily net assets attributable to Institutional Class shares. This contractual limitation is in effect until February 28, 2021, and may not be terminated without the approval of the Board of Directors of The RBB Fund, Inc. Prior to October 1, 2019, the Fund’s management fee was 1.00%.

Accordingly, the “Expenses and Fees” table and “Example” in the section entitled “SUMMARY SECTION – Boston Partners Small Cap Value Fund II” of the Prospectus are hereby deleted and replaced with the following:

Expenses and Fees

This table describes the fees and expenses that you may pay if you buy and hold Institutional Class shares of the Fund.

	Institutional Class
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Management fees(1)	0.95%
Other expenses	0.14%
Acquired fund fees and expenses(2)	0.01%
Total annual Fund operating expenses	1.10%

(1)  Prior to October 1, 2019, the management fee was 1.00%.

(2)  Acquired fund fees and expenses are indirect fees and expenses that the Fund incurs from investing in the shares of other mutual funds, including money market funds and exchange traded funds.

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $100,000 in the Fund for the time periods indicated and that you sell all of your shares at the end of the period. The Example also assumes that your investment has a 5% return each year and that the operating expenses of the Fund remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year		3 Years		5 Years		10 Years
Institutional Class		$1,121		$3,497		$6,062		$13,402

* * * * *

Please retain this supplement for your reference.

XML

Label

Element

Value

Institutional Class Prospectus | Boston Partners Small Cap Value Fund II

Risk/Return:

rr_RiskReturnAbstract

Supplement to Prospectus [Text Block]

rr_SupplementToProspectusTextBlock

THE RBB FUND, INC.

Boston Partners Investment Funds

Boston Partners Small Cap Value Fund II (the “Fund”)

Institutional Class (BPSIX)

Supplement dated October 1, 2019

to the Prospectus and Statement of Additional Information, each dated
December 31, 2018

Effective as of October 1, 2019, Boston Partners Global Investors, Inc., the investment adviser to the Fund (the “Adviser”), has contractually agreed to lower its investment advisory fee to 0.95% of the Fund’s average daily net assets. The Adviser has agreed to waive its advisory fee and/or reimburse expenses in order to limit Total Annual Fund Operating Expenses (excluding short sale dividend expenses, brokerage commissions, extraordinary items, interest or taxes) to 1.10% of the Fund’s average daily net assets attributable to Institutional Class shares. This contractual limitation is in effect until February 28, 2021, and may not be terminated without the approval of the Board of Directors of The RBB Fund, Inc. Prior to October 1, 2019, the Fund’s management fee was 1.00%.

Accordingly, the “Expenses and Fees” table and “Example” in the section entitled “SUMMARY SECTION – Boston Partners Small Cap Value Fund II” of the Prospectus are hereby deleted and replaced with the following:

Expenses and Fees

This table describes the fees and expenses that you may pay if you buy and hold Institutional Class shares of the Fund.

	Institutional Class
Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Management fees(1)	0.95%
Other expenses	0.14%
Acquired fund fees and expenses(2)	0.01%
Total annual Fund operating expenses	1.10%

(1)  Prior to October 1, 2019, the management fee was 1.00%.

(2)  Acquired fund fees and expenses are indirect fees and expenses that the Fund incurs from investing in the shares of other mutual funds, including money market funds and exchange traded funds.

Example

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $100,000 in the Fund for the time periods indicated and that you sell all of your shares at the end of the period. The Example also assumes that your investment has a 5% return each year and that the operating expenses of the Fund remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

	1 Year		3 Years		5 Years		10 Years
Institutional Class		$1,121		$3,497		$6,062		$13,402

* * * * *

Please retain this supplement for your reference.

Risk/Return [Heading]

rr_RiskReturnHeading

Boston Partners Small Cap Value Fund II