X0306 4 2018-06-18 0 0001604464 Atara Biotherapeutics, Inc. ATRA 0001329959 Gallagher Carol Giltner C/O ATARA BIOTHERAPEUTICS, INC. 611 GATEWAY BOULEVARD, SUITE 900 SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Common Stock 2018-06-18 4 S 0 2100 44.68 D 110592 D Common Stock 2018-06-18 4 S 0 400 45.29 D 110192 D Transaction pursuant to Rule 10b5-1 Plan adopted October 14, 2016. The price in Column 4 is a weighted average sale price. The prices actually received ranged from $44.10 to $45.10. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. The price in Column 4 is a weighted average sale price. The prices actually received ranged from $45.25 to $45.45. The reporting person will provide to the issuer, any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range. /s/ David Tucker, Attorney-in-Fact 2018-06-19