SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

Atara Biotherapeutics, Inc.

(Name of Issuer)

Common Stock, par value $0.0001

(Title of Class of Securities)

046513107

(CUSIP Number)

December 31, 2019

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

* The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (the “Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Atara Biotherapeutics, Inc.

611 Gateway Blvd., Suite 900

South San Francisco, California 94080

This Schedule 13G (the “Schedule 13G”) is being filed on behalf of each of the following persons (each, a “Reporting Person”):

The Schedule 13G relates to Shares (as defined herein) held for the accounts of Maverick Capital, Ltd.’s clients.

The address of the principal business office of (i) Maverick Capital, Ltd. and Maverick Capital Management, LLC is 1900 N. Pearl Street, 20th Floor, Dallas, Texas 75201, and (ii) Mr. Ainslie and Mr. Warford is 767 Fifth Avenue, 11th Floor, New York, New York 10153.

Common Stock, par value $0.0001 (the “Shares”).

046513107

If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution: _______________

Ownership as of December 31, 2019 is incorporated by reference to items (5) – (9) and (11) of the cover page of the Reporting Person.

Maverick Capital, Ltd. is an investment adviser registered under Section 203 of the Investment Advisers Act of 1940 and, as such, may be deemed to have beneficial ownership of the Shares which are the subject of this filing through the investment discretion it exercises over its clients’ accounts. Maverick Capital Management, LLC is the General Partner of Maverick Capital, Ltd. Mr. Ainslie is the manager of Maverick Capital Management, LLC. Mr. Warford serves as the Chairman of the Stock Committee of Maverick Capital, Ltd.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

By signing below each of the Reporting Persons certifies that, to the best of such person’s knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

EXHIBIT INDEX

Exhibit 24.A

Power of Attorney

KNOW ALL MEN BY THESE PRESENTS, that I, Lee S. Ainslie III, hereby make, constitute and appoint Mark Gurevich as my agent and attorney-in -fact for the purpose of executing (i) in my personal capacity or (ii) in my capacity as manager or other officer or representative of Maverick Capital Management, LLC, Maverick Capital, Ltd. or any affiliate of either, all documents to be filed with or delivered to any foreign or domestic governmental or regulatory body or other person pursuant to any legal or regulatory requirement relating to the issuance, acquisition, ownership, management or disposition of securities or investments, including without limitation all documents required to be filed with the United States Securities and Exchange Commission pursuant to Sections 13 and 16 of the Securities Exchange Act of 1934 and any joint filing agreements pursuant to Rule 13d-1(k).

All past acts of the attorney-in-fact in furtherance of the foregoing are hereby ratified and confirmed.

This power of attorney shall be valid from the date hereof until revoked by me.

IN WITNESS WHEREOF, I have executed this instrument as of the 15^th day of March, 2018.

Exhibit 24.B

Power of Attorney

KNOW ALL MEN BY THESE PRESENTS, that I, Andrew H. Warford, hereby make, constitute and appoint Mark Gurevich as my agent and attorney-in-fact for the purpose of executing (i) in my personal capacity or (ii) in my capacity as manager or other officer or representative of Maverick Capital, Ltd. or any affiliate of either, all documents to be filed with or delivered to any foreign or domestic governmental or regulatory body or other person pursuant to any legal or regulatory requirement relating to the issuance, acquisition, ownership, management or disposition of securities or investments, including without limitation all documents required to be filed with the United States Securities and Exchange Commission pursuant to Sections 13 and 16 of the Securities Exchange Act of 1934 and any joint filing agreements pursuant to Rule 13d-1(k).

All past acts of the attorney-in-fact in furtherance of the foregoing are hereby ratified and confirmed.

This power of attorney shall be valid from the date hereof until revoked by me.

IN WITNESS WHEREOF, I have executed this instrument as of the 16^th day of March, 2018.

Exhibit 99.A

Joint Filing Agreement

The undersigned hereby agree that the statement on Schedule 13G with respect to the Common Stock, par value $0.0001 of Atara Biotherapeutics, Inc., dated as of February 14, 2020, is, and any amendments thereto (including amendments on Schedule 13D) signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934.