atra-defa14a_20180614.htm

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

(Amendment No.__)

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☐	Preliminary Proxy Statement

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☐	Definitive Proxy Statement

☒	Definitive Additional Materials

☐	Soliciting Material Pursuant to § 240.14a-12

Atara Biotherapeutics, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if Other Than the Registrant)

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*** Exercise Your Right to Vote ***

Important Notice Regarding the Availability of Proxy Materials for the
Stockholder Meeting to Be Held on June 14, 2018

	ATARA BIOTHERAPEUTICS, INC.	Meeting Information Meeting Type: Annual Meeting For holders as of: April 19, 2018 Date: June 14, 2018 Time: 8:00 AM PDT Location: 2430 Conejo Spectrum St. Thousand Oaks, CA 91320
	ATARA BIOTHERAPEUTICS, INC. 611 GATEWAY BLVD., SUITE 900 SOUTH SAN FRANCISCO, CA 94080	You are receiving this communication because you hold shares in the company named above. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting.

		See the reverse side of this notice to obtain proxy materials and voting instructions.

— Before You Vote —

How to Access the Proxy Materials

Proxy Materials Available to VIEW or RECEIVE:

1.Notice & Proxy Statement 2. Form 10-K

How to View Online:

Have the information that is printed in the box marked by the arrow (located on the following page) and visit: www.proxyvote.com.

How to Request and Receive a PAPER or E-MAIL Copy:

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Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 31, 2018 to facilitate timely delivery.

— How To Vote —

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Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow available and follow the instructions.

Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card.

	Voting Items
	The Board of Directors recommends you vote FOR the following:
	1. Election of Directors Nominees: 01 Eric L. Dobmeier 02 William K. Heiden 03 Beth Seidenberg, M.D. The Board of Directors recommends you vote FOR the following proposal: 2. Ratification of the selection of Deloitte & Touche, LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2018. NOTE: In their discretion, upon such other matters that may properly come before the meeting or any adjournment or adjournments thereof.