X0508 4 2024-05-16 0001499422 RBB Bancorp RBB 0001778913 Kao Christina 1055 WILSHIRE BLVD SUITE 1200 LOS ANGELES CA 90017 1 0 Common Stock, No Par Value 2024-05-16 4 M 0 5447 0 A 217910 D Restricted Stock Units 0 2024-05-16 4 M 0 5447 0 D Restricted Stock Units 6147 700 D There will be no expiration date once restricted stock units vest. These restricted stock units vest in two installments: 5,447 immediately vested on the date of grant and 700 vest in one year from the date of grant. Reporting person received 1,600 restricted stock units, of which 900 vested immediately and 700 are to vest one year from the date of grant. In addition, reporting person received 4,547 of restricted stock units, which vested immediately. /s/ Christina Kao 2024-05-16