X0306 4 2021-11-23 0 0001828673 HCW Biologics Inc. HCWB 0001866256 Byam Rebecca C/O HCW BIOLOGICS INC 2929 N. COMMERCE PARKWAY MIRAMAR FL 33025 0 1 0 0 Chief Financial Officer Common Stock 2021-11-23 4 M 0 27000 0.14 A 89000 D Stock Option Grant (Right to Buy) 0.14 2021-11-23 4 M 0 27000 0.00 D 2029-12-19 Common Stock 27000 80999 D These option shares were part of a stock option grant covering 135,000 shares of common stock. 20% of the total shares subject to the stock option grant vested on October 10, 2020; 20% of the total shares subject to the stock option grant vested on October 10, 2021; 25% of the total shares subject to the stock option grant will vest on October 10, 2022; and 35% of the total shares subject to the stock option grant will vest on October 10, 2023, subject to her continuous service through the applicable vesting date. The option is subject to additional vesting acceleration pursuant to her Employment Agreement. /s/ Nicole Valdivieso, as Attorney-in-Fact for Rebecca A. Byam 2021-11-26