X0306 4/A 2020-11-13 2020-11-16 0 0001604464 Atara Biotherapeutics, Inc. ATRA 0001702457 Newell Joe C/O ATARA BIOTHERAPEUTICS, INC. 611 GATEWAY BLVD., SUITE 900 SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Operations Officer Employee Stock Option (Right to Buy) 12.15 2020-11-13 4 M 0 667 0.00 D 2030-02-28 Common Stock 667 52333 D Employee Stock Option (Right to Buy) 12.15 2020-11-13 4 M 0 2833 0.00 D 2030-02-28 Common Stock 2833 14167 D Transaction pursuant to Rule 10b5-1 Plan adopted September 14, 2020. 1/48th of the shares subject to the stock option vest and become exercisable each month with the initial installment vesting on April 1, 2020, subject to the reporting person's continuous service. This amendment is being filed solely to correct the ending balances of the derivative securities beneficially owned in Column 9. /s/ David Tucker, Attorney-in-Fact for Joe Newell 2020-12-18