X0306 4 2017-02-10 0 0001604464 Atara Biotherapeutics, Inc. ATRA 0001612090 Soffer Gad 611 GATEWAY BOULEVARD SUITE 900 SOUTH SAN FRANCISCO CA 94080 0 1 0 0 EVP & Chief Strategy Officer Common Stock 2017-02-10 4 S 0 5874 15.42 D 269938 D Common Stock 2017-02-10 4 S 0 400 16.13 D 269538 D Transaction pursuant to Rule 10b5-1 Plan adopted September 26, 2016. Shares sold to cover tax liability from settlement of RSUs. The price in Column 4 is a weighted average sale price. The prices actually received ranged from $15.00 to $15.90. 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 $16.00 to $16.25. 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/ Tina Gullotta, Attorney-in-Fact for Gad Soffer 2017-02-13