X0206 3 2025-03-31 0 0001604464 Atara Biotherapeutics, Inc. ATRA 0002064348 Grant-Huerta Yanina C/O ATARA BIOTHERAPEUTICS, INC. 1280 RANCHO CONEJO BOULEVARD THOUSAND OAKS CA 91320 true Chief Accounting Officer Common Stock 39285 D Employee Stock Option (Right to Buy) 198 2024-04-06 2030-04-30 Common Stock 800 D Employee Stock Option (Right to Buy) 97.75 2025-03-01 2033-02-28 Common Stock 1100 D Employee Stock Option (Right to Buy) 97.75 2033-02-28 Common Stock 550 D Employee Stock Option (Right to Buy) 11 2024-07-31 2034-01-05 Common Stock 275 D Includes an aggregate 33,840 restricted stock units ("RSUs"), which are comprised of: (i) 51 RSUs that vest on November 15, 2025; (ii) 3,614 RSUs that vest as to 1/4th of the shares on May 15, 2025, and each of the next three (3) Quarterly Vesting Dates (as defined herein); (iii) 1,125 RSUs that vest as to 1/5th of the shares on May 15, 2025, and each of the next four (4) Quarterly Vesting Dates; and (iv) 29,050 RSUs that vest as to 1/8th of the shares on May 15, 2025, and each of the next seven (7) Quarterly Vesting Dates, each of which is subject to the reporting person's continuous service. "Quarterly Vesting Date" means March 1, May 15, August 15, and November 15 of each year, provided that if such date falls on a weekend or holiday, the "Quarterly Vesting Date" shall be the first (1st) business day after such date. 1/12th of the shares subject to the stock option vested and became exercisable on April 1, 2025, and the remaining shares vest in equal monthly installments over the following eleven (11) months, subject to the reporting person's continuous service. Exhibit List: Exhibit 24 - Power of Attorney /s/ John Chao, Attorney-in-Fact for Yanina Grant-Huerta 2025-04-10