X0306 4 2023-03-01 0001604464 Atara Biotherapeutics, Inc. ATRA 0001553335 Dupont Jakob C/O ATARA BIOTHERAPEUTICS, INC. 2380 CONEJO SPECTRUM ST, SUITE 200 THOUSAND OAKS CA 91320 true EVP, Head of R&D Common Stock 2023-03-01 4 A 0 141328 0 A 295868 D Employee Stock Option (Right to Buy) 3.91 2023-03-01 4 A 0 317987 0 A 2033-02-28 Common Stock 317987 317987 D These restricted stock units vest in 12 equal quarterly installments on each Company Quarterly Vesting Date (as defined below), with the initial installment vesting on May 15, 2023, subject to the reporting person's continuous service. "Company Quarterly Vesting Date" means March 1, May 15, August 15 and November 15 of each year. 1/36th of the shares subject to the stock option vest and become exercisable each month, with the initial installment vesting on April 1, 2023, subject to the reporting person's continuous service. /s/ Jeff Kiekhofer, Attorney-in-Fact for Jakob Dupont 2023-03-03