X0306 4 2022-05-17 0001604464 Atara Biotherapeutics, Inc. ATRA 0001742696 Koppikar Utpal C/O ATARA BIOTHERAPEUTICS, INC. 611 GATEWAY BLVD., SUITE 900 SOUTH SAN FRANCISCO CA 94080 true Chief Financial Officer Common Stock 2022-05-17 4 S 0 4616 5.316 D 208558 D Common Stock 2022-05-17 4 S 0 966 5.317 D 207592 D Shares sold pursuant to a 10b5-1 arrangement to satisfy tax obligations in connection with the vesting of previously granted restricted stock units. The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on May 17, 2022 and May 18, 2022 on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employee. /s/ David Tucker, Attorney-in-Fact for Utpal Koppikar 2022-05-19