X0306 4 2023-02-07 0 0001786205 Arcellx, Inc. ACLX 0001789632 Heery Christopher C/O ARCELLX, INC. 25 WEST WATKINS MILL ROAD, SUITE A GAITHERSBURG MD 20878 0 1 0 0 Chief Medical Officer Common Stock 2023-02-07 4 M 0 22555 0.00 A 22555 D Common Stock 2023-02-09 4 S 0 6966 30.7685 D 15589 D Restricted Stock Unit 2023-02-07 4 M 0 22555 0.00 D Common Stock 22555 45111 D Each restricted stock unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock. Represents the number of shares sold to cover the tax withholding obligations in connection with the vesting of RSUs and does not represent a discretionary sale by the Reporting Person. Subject to the Reporting Person continuing to be a Service Provider (as defined in the Issuer's 2022 Equity Incentive Plan) through each applicable vesting date, one-third (1/3rd) of the RSUs subject to the award will vest each year following RSU Grant Date on the same day of the month as the RSU Grant Date (or, if there is no corresponding day in a particular month, then the last day of the month) over three (3) years. "RSU Grant Date" shall mean February 7, 2022. /s/ Michelle Gilson, as Attorney-in-Fact 2023-02-09