Atara Biotherapeutics (ATRA) Form 4 Atara Biotherapeutics / Mitchall G. Clark ownership change

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Clark Mitchall G.

(Last) (First) (Middle)

611 GATEWAY BOULEVARD

SUITE 900

(Street)

SOUTH SAN FRANCISCO CA 94080

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Atara Biotherapeutics, Inc. [ ATRA ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director	10% Owner
X	Officer (give title below)	Other (specify below)
EVP & Chief R & QA Officer

3. Date of Earliest Transaction (Month/Day/Year)
05/15/2018

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/15/2018		M		4,808	A	$0.00(1)	138,479	D
Common Stock	05/16/2018		S(2)		4,347	D	$46.04(3)	134,132	D
Common Stock	05/16/2018		S(2)		300	D	$46.3	133,832	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	(4)	05/15/2018		M			4,808	(5)	(6)	Common Stock	4,808	$0.00	0	D

Explanation of Responses:

1. Shares issued upon settlement of vested restricted stock units ("RSUs").

2. Transaction pursuant to Rule 10b5-1 Plan adopted January 25, 2018.

3. The price in Column 4 is a weighted average sale price. The prices actually received ranged from $45.25 to $46.25. 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.

4. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock or a cash settlement.

5. The RSUs were granted with both (a) a liquidity event-based vesting condition and (b) a service-based vesting condition, both of which conditions must be satisfied in order for the RSUs to vest. The liquidity event-based condition was satisfied upon the closing of the Issuer's initial public offering (the "IPO"). The shares that vested on the closing date of the IPO, and the shares that vested thereafter through May 15, 2015, were settled on May 15, 2015. The service-based vesting condition provides that 25% of the total number of shares on March 17, 2015 and 1/48th of the total number of shares monthly thereafter, subject to the holder's continuous service through each such date.

6. The earlier of (i) March 27, 2021 or (ii) the recepient's termination date.

Remarks:

	/s/ David Tucker, Attorney-in-Fact for Mitchall G. Clark	05/16/2018
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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