X0306 4 2018-12-03 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 Tech. Operations Officer Common Stock 2018-12-03 4 M 0 1500 20.40 A 33358 D Common Stock 2018-12-03 4 S 0 973 40.61 D 32385 D Common Stock 2018-12-03 4 S 0 400 41.97 D 31985 D Common Stock 2018-12-03 4 S 0 127 42.54 D 31858 D Employee Stock Option (Right to Buy) 20.40 2018-12-03 4 M 0 1500 0.00 D 2024-04-03 Common Stock 1500 72500 D Transaction pursuant to Rule 10b5-1 Plan adopted May 29, 2018. The price in Column 4 is a weighted average sale price. The prices actually received ranged from $40.30 to $41.28. 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 $41.40 to $42.38. 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 $42.49 to $42.66. 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. 25% of the shares shall vest one year from April 3, 2017, and the remaining shares shall vest in 36 equal monthly installment thereafter, subject to the reporting person's continuous service. /s/ David Tucker, Attorney-in-Fact for Joe Newell 2018-12-03