X0306 4 2018-05-15 0 0001604464 Atara Biotherapeutics, Inc. ATRA 0001612095 Haqq Christopher 611 GATEWAY BOULEVARD SUITE 900 SOUTH SAN FRANCISCO CA 94080 0 1 0 0 EVP, R&D & Chief Scientific Of Common Stock 2018-05-15 4 M 0 25000 11.00 A 357905 D Common Stock 2018-05-15 4 S 0 6885 44.44 D 351020 D Common Stock 2018-05-15 4 S 0 9638 45.21 D 341382 D Common Stock 2018-05-15 4 S 0 9252 46.02 D 332130 D Common Stock 17312 I See footnote Common Stock 2688 I See footnote Employee Stock Option (Right to Buy) 11.00 2018-05-15 4 M 0 25000 0.00 D 2021-10-15 Common Stock 25000 25000 D Transaction pursuant to Rule 10b5-1 Plan adopted January 25, 2018. The price in Column 4 is a weighted average sale price. The prices actually received ranged from $43.75 to $44.75. 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 $44.80 to $45.80. 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 $45.85 to $46.30. 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 shares are held by the Chris Haqq 2014 GRAT, of which the Reporting Person is trustee. The shares are held by The Havenside Trust, of which the Reporting Person is trustee. 1/48th of the shares subject to the stock option vest and become exercisable each month following October 15, 2014. /s/ David Tucker, Attorney-in-Fact for Christopher Haqq 2018-05-16