Sec Form 4 Filing - Fan Gary @ RBB Bancorp - 2025-06-05

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Fan Gary 2. Issuer Name and Ticker or Trading Symbol RBB Bancorp [ RBB] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP/Chief Operations Officer (Last) (First) (Middle) 1055 WILSHIRE BLVD, SUITE 1200 3. Date of Earliest Transaction (MM/DD/YY) 06/05/2025 (Street) LOS ANGELES, CA90017 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, No Par Value 06/05/2025 S 1,451 D $ 16.73 0 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Options $ 21.17 ( 1 ) 12/20/2032 Stock Options 18,000 18,000 D Restricted Stock Units $ 0 ( 2 ) ( 3 ) Common Stock ( 8 ) 2,022 2,022 D Restricted Stock Units $ 0 ( 4 ) ( 3 ) Common Stock ( 8 ) 2,629 2,629 D Performance Stock Units $ 0 ( 5 ) ( 3 ) Common Stock ( 8 ) 5,916 5,916 D Restricted Stock Units $ 0 05/08/2025 A 4,356 ( 6 ) ( 3 ) Common Stock ( 8 ) 4,356 ( 8 ) $ 0 4,356 ( 8 ) D Performance Stock Units $ 0 05/08/2025 A 6,534 ( 7 ) ( 3 ) Common Stock ( 8 ) 6,534 ( 8 ) $ 0 6,534 ( 8 ) D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Fan Gary 1055 WILSHIRE BLVD SUITE 1200 LOS ANGELES, CA90017 EVP/Chief Operations Officer Signatures /s/ Gary Fan 06/06/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These options vest in five equal annual installments beginning one year after the 12/05/2022 date of grant. ( 2 )These restricted stock units vest in three equal installments beginning one year after 02/21/2024 date of grant. ( 3 )There will be no expiration date once restricted stock units vest. ( 4 )These restricted stock units vest in three equal installments beginning one year after 03/20/2024 date of grant. ( 5 )These performance stock units ("PSUs") will vest conditionally on the achievement of certain performance goals and an employment condition. The reported PSUs will vest at the expiration of a three-year period beginning on 03/20/2024 subject to the Reporting Person's satisfaction of the employment condition. ( 6 )These restricted stock units vest in three equal installments beginning one year after 05/08/2025 date of grant. ( 7 )Performance Stock Units ("PSUs") to vest conditionally on the achievement of certain performance goals and an employment condition. The PSUs are awarded at a target level and have the opportunity to vest at 150% of such target level; The reported PSUs represent the maximum award that may be achieved and ultimately vest. The reported PSUs will vest at the expiration of a three-year period beginning on 05/08/2025 subject to the Reporting Person's satisfaction of the employment condition. ( 8 )On May 12, 2025 due to an administrative error, the Reporting Person filed a Form 4 which inadvertently omitted information from the transactional columns in Table II and overstated the amount of RSUs and PSUs granted to the Reporting Person on May 8, 2025. The Form 4 has also been amended to clarify that grants of RSUs and PSUs will be settled in common stock.

Remarks: A total of 1,451 shares sold for $16.73 on June 5, 2025.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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