X0407 4 2023-05-31 0001604464 Atara Biotherapeutics, Inc. ATRA 0001184592 SEIDENBERG BETH C C/O ATARA BIOTHERAPEUTICS, INC. 2380 CONEJO SPECTRUM ST, SUITE 200 THOUSAND OAKS CA 91320 true false Common Stock 2023-05-31 4 A 0 57000 0 A 115689 D Common Stock 1822228 I See footnote Common Stock 54422 I See footnote Common Stock 197 I See footnote Common Stock 197 I See footnote Non-Qualified Stock Option (Right to Buy) 1.53 2023-05-31 4 A 0 79500 0 A 2033-05-30 Common Stock 79500 79500 D These restricted stock units shall vest on the earlier of May 31, 2024 or the date of the next annual meeting of stockholders, subject to the Reporting Person's continuous service. The option shall vest on the earlier of May 31, 2024 or the date of the next annual meeting of stockholders, subject to the Reporting Person's continuous service. The shares are directly held by Kleiner Perkins Caufield & Byers XV, LLC ("KPCB XV"). All shares are held for convenience in the name of "KPCB Holdings, Inc., as nominee". The managing member of KPCB XV is KPCB XV Associates, LLC ("XV Associates"). The voting and dispositive control over the shares is shared by individual managing members of XV Associates, none of whom has veto power. The shares are directly held by KPCB XV Founders Fund, LLC ("KPCB XV FF"). All shares are held for convenience in the name of "KPCB Holdings, Inc., as nominee". The managing member of KPCB XV FF is XV Associates. The voting and dispositive control over the shares is shared by individual managing members of XV Associates, none of whom has veto power. Shares held by the Michael J. Seidenberg Irrevocable Trust, established July 1, 2013, of which the Reporting Person is a trustee. Shares held by the Samuel B. Seidenberg Irrevocable Trust, established July 1, 2013, of which the Reporting Person is a trustee. Exhibit List: Exhibit 24 - Power of Attorney /s/ Jeff Kiekhofer, Attorney-in-Fact 2023-06-02