X0306 4 2021-08-20 0 0001661460 Poseida Therapeutics, Inc. PSTX 0001766302 Spear Matthew A. C/O POSEIDA THERAPEUTICS, INC. 9390 TOWNE CENTRE DRIVE, STE 200 SAN DIEGO CA 92121 0 1 0 0 Chief Medical Officer Common Stock 2021-08-20 4 M 0 4000 1.322 A 45485 D Common Stock 2021-08-20 4 S 0 4000 8.7854 D 41485 D Stock Option (Right to Buy) 1.322 2021-08-20 4 M 0 4000 0.00 D 2026-06-19 Common Stock 4000 90861 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 22, 2021. The reported price in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.66 to $8.89 per share, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The stock option is fully vested and exercisable. /s/ Harry J. Leonhardt, Attorney-in-Fact 2021-08-24