Atara Biotherapeutics (ATRA) awards 20,300 RSUs to Chief Accounting Officer

Rhea-AI Filing Summary

Grant-Huerta Yanina reported acquisition or exercise transactions in this Form 4 filing.

Atara Biotherapeutics reported that Chief Accounting Officer Yanina Grant-Huerta received a grant of 20,300 restricted stock units (RSUs) of common stock at no cost. Following this award, she holds 52,050 shares of common stock directly.

The RSUs vest in eight equal installments of one-eighth each. Vesting begins on the second Quarterly Vesting Date after March 9, 2026 and continues on the next seven Quarterly Vesting Dates, subject to her continuous employment. Quarterly Vesting Dates are March 1, May 15, August 15, and November 15, or the first business day thereafter.

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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Grant-Huerta Yanina

(Last) (First) (Middle)

C/O ATARA BIOTHERAPEUTICS, INC.

1280 RANCHO CONEJO BOULEVARD

(Street)

THOUSAND OAKS CA 91320

(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)
	Chief Accounting Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/09/2026

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	03/09/2026		A		20,300(1)	A	$0	52,050	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

Explanation of Responses:

1. These restricted stock units ("RSUs") vest as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the second Quarterly Vesting Date (as defined below) following March 9, 2026, and as to 1/8th of the total number of shares (rounded down to the next whole number of shares) on the next seven Quarterly Vesting Dates, such that all of the shares subject to the RSUs shall be vested on the last Quarterly Vesting Date, subject to the reporting person's continuous employment. "Quarterly Vesting Date" means March 1, May 15, August 15, and November 15 of each year, provided that if such date falls on a weekend or holiday, the Quarterly Vesting Date shall be the first business day after such date.

	/s/ John Chao, Attorney-in-Fact for Yanina Grant-Huerta	03/11/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Atara Biotherapeutics (ATRA) report in this Form 4?

Atara Biotherapeutics reported a grant of 20,300 restricted stock units (RSUs) of common stock to its Chief Accounting Officer, Yanina Grant-Huerta. The award is a compensation-related grant, not an open-market purchase or sale, and was received at no cash cost per share.

How many Atara Biotherapeutics RSUs were granted to the Chief Accounting Officer?

The Chief Accounting Officer received 20,300 RSUs of Atara Biotherapeutics common stock. These RSUs represent the right to receive an equivalent number of shares over time, subject to vesting. The grant increases her direct holdings to 52,050 shares after the transaction reported in this filing.

What is the vesting schedule for the 20,300 Atara Biotherapeutics RSUs?

The 20,300 RSUs vest in eight equal installments of one-eighth each. Vesting starts on the second Quarterly Vesting Date after March 9, 2026, then continues on the next seven Quarterly Vesting Dates, provided the reporting person remains continuously employed throughout the vesting period.

How does Atara Biotherapeutics define Quarterly Vesting Dates for these RSUs?

Quarterly Vesting Dates are defined as March 1, May 15, August 15, and November 15 of each year. If any such date falls on a weekend or holiday, the Quarterly Vesting Date shifts to the first business day after that date for vesting purposes.

What are Yanina Grant-Huerta’s Atara Biotherapeutics share holdings after this RSU grant?

After receiving the 20,300 RSU grant, Yanina Grant-Huerta is reported as directly holding 52,050 shares of Atara Biotherapeutics common stock. This figure reflects her position immediately following the compensation-related award disclosed in the Form 4 filing.

Were the Atara Biotherapeutics RSUs granted to the CAO issued at a purchase price?

The 20,300 RSUs were granted at a reported price of $0.00 per share. This indicates the award is part of equity-based compensation rather than a cash purchase, with value realized as the RSUs vest into shares over the defined schedule.