X0508 4 2024-01-08 0001604464 Atara Biotherapeutics, Inc. ATRA 0001809916 Murugan Amar C/O ATARA BIOTHERAPEUTICS, INC. 2380 CONEJO SPECTRUM ST, SUITE 200 THOUSAND OAKS CA 91320 true EVP, Chief Legal Officer false Common Stock 2024-01-08 4 A 0 475000 0 A 737565 D These restricted stock units vest as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the second Quarterly Vesting Date (as defined below) following January 8, 2024, and as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the next seven Quarterly Vesting Dates, such that all of the shares shall be vested on the last Quarterly Vesting Date, 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 business day after such date. Includes 5,481 shares purchased under the Issuer's Employee Stock Purchase Plan on November 30, 2023. /s/ Jeff Kiekhofer, Attorney-in-Fact for Amar Murugan 2024-01-09