ATRA

Atara Biotherapeutics, Inc.

Insider trading activity for Atara Biotherapeutics, Inc., straight from SEC Form 4 filings. Net figures below count open-market buys and sales only — grants, option exercises and tax withholding are excluded because they are compensation, not decisions to trade.

Past 3 months

+$959.1K

net buying

Bought(1 · 1 insiders): $1M
Sold(1 · 1 insiders): $40.9K

Past 6 months

+$2.5M

net buying

Bought(2 · 2 insiders): $5.7M
Sold(4 · 3 insiders): $3.3M

Past 12 months

+$1.9M

net buying

Bought(2 · 2 insiders): $5.7M
Sold(18 · 3 insiders): $3.9M

Transaction history

The 55 most recent Form 4 transactions.

Open in screener →

Insider transactions, newest first: date, security, transaction type, size and a link to the filing each row came from.
Date	Insider	Role	Type	Shares	Price	Value	Δ Own	Filing
Sep 4	Cherry Brian N	Director	PBUY★	104,166	$9.60	$1M	+167.2%	Open the original filing on SEC.gov
Aug 17	Nguyen AnhCo	President and CEO	SSELL	5,062	$8.08	$40.9K	-3.7%	Open the original filing on SEC.gov
Jul 22	Redmile Group, LLC	Director	MEXER◆	55,387	—	—	—	Open the original filing on SEC.gov
Jul 22	Redmile Group, LLC	Director	MEXER◆	38,735	—	—	—	Open the original filing on SEC.gov
Jul 22	Redmile Group, LLC	Director	MEXER◆	101,089	—	—	—	Open the original filing on SEC.gov
Jul 22	Redmile Group, LLC	Director	FTAX	60	—	—	<0.1%	Open the original filing on SEC.gov
Jul 22	Redmile Group, LLC	Director	MEXER	195,211	—	—	+44.2%	Open the original filing on SEC.gov
Jun 11	Cherry Brian N	Director	AGRANT	24,000	—	—	+62.6%	Open the original filing on SEC.gov
Jun 9	Heiden William K	Director	AGRANT	12,000	—	—	+54.1%	Open the original filing on SEC.gov
Jun 9	Fust Matthew K	Director	AGRANT	12,000	—	—	+66.0%	Open the original filing on SEC.gov
Jun 9	Ciongoli Gregory Austin	Director, 10% Owner	AGRANT	12,000	—	—	—	Open the original filing on SEC.gov
May 18	Nguyen AnhCo	President and CEO	SSELL	5,241	$9.13	$47.8K	-3.7%	Open the original filing on SEC.gov
May 18	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	2,414	$9.13	$22K	-4.6%	Open the original filing on SEC.gov
May 7	Huang James	Director, 10% Owner	SSELL	313,446	$10.10	$3.2M	-23.7%	Open the original filing on SEC.gov
May 7	EcoR1 Capital, LLC	10% Owner	PBUY★	507,407	$9.35	$4.7M	+48.6%	Open the original filing on SEC.gov
Mar 17	Huang James	Director, 10% Owner	MEXER◆	259,163	$6.61	$1.7M	—	Open the original filing on SEC.gov
Mar 17	Huang James	Director, 10% Owner	FTAX	5	$5.23	$26	0.0%	Open the original filing on SEC.gov
Mar 17	Huang James	Director, 10% Owner	MEXER	259,163	$0.0001	$26	+531.8%	Open the original filing on SEC.gov
Mar 9	Nguyen AnhCo	President and CEO	AGRANT	81,100	—	—	+130.8%	Open the original filing on SEC.gov
Mar 9	Grant-Huerta Yanina	Chief Accounting Officer	AGRANT	20,300	—	—	+63.9%	Open the original filing on SEC.gov
Mar 2	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	100	$5.08	$508	-0.3%	Open the original filing on SEC.gov
Mar 2	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	377	$5.08	$1.9K	-1.2%	Open the original filing on SEC.gov
Mar 2	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	1,603	$5.08	$8.1K	-4.7%	Open the original filing on SEC.gov
Mar 2	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	24	$5.08	$122	<0.1%	Open the original filing on SEC.gov
Mar 2	Nguyen AnhCo	President and CEO	SSELL	1,442	$5.09	$7.3K	-2.3%	Open the original filing on SEC.gov
Mar 2	Nguyen AnhCo	President and CEO	SSELL	1,298	$5.09	$6.6K	-2.0%	Open the original filing on SEC.gov
Mar 2	Nguyen AnhCo	President and CEO	SSELL	58	$5.08	$295	<0.1%	Open the original filing on SEC.gov
Mar 2	Nguyen AnhCo	President and CEO	SSELL	198	$5.08	$1K	-0.3%	Open the original filing on SEC.gov
Jan 12	Huang James	Director, 10% Owner	SSELL	80,554	$6.07	$489K	-5.7%	Open the original filing on SEC.gov
Nov 28, 2025	Huang James	Director, 10% Owner	MEXER◆	48,737	$6.61	$322.1K	—	Open the original filing on SEC.gov
Nov 28, 2025	Huang James	Director, 10% Owner	FTAX	1	$14.03	$14	0.0%	Open the original filing on SEC.gov
Nov 28, 2025	Huang James	Director, 10% Owner	MEXER	48,737	$0.0001	$5	—	Open the original filing on SEC.gov
Nov 17, 2025	Nguyen AnhCo	President and CEO	SSELL	56	$13.19	$739	<0.1%	Open the original filing on SEC.gov
Nov 17, 2025	Nguyen AnhCo	President and CEO	SSELL	2,859	$13.19	$37.7K	-4.2%	Open the original filing on SEC.gov
Nov 17, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	74	$13.19	$976	-0.2%	Open the original filing on SEC.gov
Nov 17, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	85	$13.19	$1.1K	-0.3%	Open the original filing on SEC.gov
Nov 17, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	1,645	$13.19	$21.7K	-4.7%	Open the original filing on SEC.gov
Aug 18, 2025	Nguyen AnhCo	President and CEO	SSELL	1,620	$11.62	$18.8K	-2.3%	Open the original filing on SEC.gov
Aug 18, 2025	Nguyen AnhCo	President and CEO	SSELL	1,281	$11.62	$14.9K	-1.8%	Open the original filing on SEC.gov
Aug 18, 2025	Nguyen AnhCo	President and CEO	SSELL	57	$11.61	$662	<0.1%	Open the original filing on SEC.gov
Aug 18, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	1,668	$11.61	$19.4K	-4.5%	Open the original filing on SEC.gov
Aug 18, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	86	$11.61	$999	-0.2%	Open the original filing on SEC.gov
Aug 18, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	55	$11.61	$639	-0.1%	Open the original filing on SEC.gov
Aug 15, 2025	Huang James	Director, 10% Owner	PBUY▲	55,000	$12.19	$670.4K	+4.1%	Open the original filing on SEC.gov
Jul 17, 2025	Huang James	Director, 10% Owner	PBUY	19,335	$9.64	$186.4K	+1.5%	Open the original filing on SEC.gov
Jun 10, 2025	Gallagher Carol Giltner	Director	AGRANT	7,828	—	—	+31.1%	Open the original filing on SEC.gov
Jun 10, 2025	Fust Matthew K	Director	AGRANT	7,828	—	—	+75.6%	Open the original filing on SEC.gov
Jun 10, 2025	Touchon Pascal	Director	AGRANT	7,828	—	—	+11.2%	Open the original filing on SEC.gov
Jun 10, 2025	Roncarolo Maria Grazia	Director	AGRANT	7,828	—	—	+82.0%	Open the original filing on SEC.gov
Jun 10, 2025	Mallik Ameet	Director	AGRANT	7,828	—	—	+86.0%	Open the original filing on SEC.gov
Jun 10, 2025	Heiden William K	Director	AGRANT	7,828	—	—	+54.5%	Open the original filing on SEC.gov
May 16, 2025	Adiumentum Capital Fund…	Director, 10% Owner	AGRANT◆	227,000	$6.61	$1.5M	—	Open the original filing on SEC.gov
May 16, 2025	Adiumentum Capital Fund…	Director, 10% Owner	AGRANT	75,572	$6.61	$499.5K	+6.7%	Open the original filing on SEC.gov
May 16, 2025	Grant-Huerta Yanina	Chief Accounting Officer	SSELL	2,218	$6.76	$15K	-5.7%	Open the original filing on SEC.gov
May 16, 2025	Nguyen AnhCo	President and CEO	SSELL	3,276	$6.76	$22.2K	-4.4%	Open the original filing on SEC.gov

PBUY★$1M

Cherry Brian N · DirectorSep 4

104,166 sh @ $9.60 · +167.2% own

SSELL$40.9K

Nguyen AnhCo · President and CEOAug 17

5,062 sh @ $8.08 · -3.7% own

MEXER◆—

Redmile Group, LLC · DirectorJul 22

55,387 sh

MEXER◆—

Redmile Group, LLC · DirectorJul 22

38,735 sh

MEXER◆—

Redmile Group, LLC · DirectorJul 22

101,089 sh

FTAX—

Redmile Group, LLC · DirectorJul 22

60 sh · <0.1% own

MEXER—

Redmile Group, LLC · DirectorJul 22

195,211 sh · +44.2% own

AGRANT—

Cherry Brian N · DirectorJun 11

24,000 sh · +62.6% own

AGRANT—

Heiden William K · DirectorJun 9

12,000 sh · +54.1% own

AGRANT—

Fust Matthew K · DirectorJun 9

12,000 sh · +66.0% own

AGRANT—

Ciongoli Gregory Austin · Director, 10%…Jun 9

12,000 sh

SSELL$47.8K

Nguyen AnhCo · President and CEOMay 18

5,241 sh @ $9.13 · -3.7% own

SSELL$22K

Grant-Huerta Yanina · Chief Accounting…May 18

2,414 sh @ $9.13 · -4.6% own

SSELL$3.2M

Huang James · Director, 10%…May 7

313,446 sh @ $10.10 · -23.7% own

PBUY★$4.7M

EcoR1 Capital, LLC · 10% OwnerMay 7

507,407 sh @ $9.35 · +48.6% own

MEXER◆$1.7M

Huang James · Director, 10%…Mar 17

259,163 sh @ $6.61

FTAX$26

Huang James · Director, 10%…Mar 17

5 sh @ $5.23 · 0.0% own

MEXER$26

Huang James · Director, 10%…Mar 17

259,163 sh @ $0.0001 · +531.8% own

AGRANT—

Nguyen AnhCo · President and CEOMar 9

81,100 sh · +130.8% own

AGRANT—

Grant-Huerta Yanina · Chief Accounting…Mar 9

20,300 sh · +63.9% own

SSELL$508

Grant-Huerta Yanina · Chief Accounting…Mar 2

100 sh @ $5.08 · -0.3% own

SSELL$1.9K

Grant-Huerta Yanina · Chief Accounting…Mar 2

377 sh @ $5.08 · -1.2% own

SSELL$8.1K

Grant-Huerta Yanina · Chief Accounting…Mar 2

1,603 sh @ $5.08 · -4.7% own

SSELL$122

Grant-Huerta Yanina · Chief Accounting…Mar 2

24 sh @ $5.08 · <0.1% own

SSELL$7.3K

Nguyen AnhCo · President and CEOMar 2

1,442 sh @ $5.09 · -2.3% own

SSELL$6.6K

Nguyen AnhCo · President and CEOMar 2

1,298 sh @ $5.09 · -2.0% own

SSELL$295

Nguyen AnhCo · President and CEOMar 2

58 sh @ $5.08 · <0.1% own

SSELL$1K

Nguyen AnhCo · President and CEOMar 2

198 sh @ $5.08 · -0.3% own

SSELL$489K

Huang James · Director, 10%…Jan 12

80,554 sh @ $6.07 · -5.7% own

MEXER◆$322.1K

Huang James · Director, 10%…Nov 28, 2025

48,737 sh @ $6.61

FTAX$14

Huang James · Director, 10%…Nov 28, 2025

1 sh @ $14.03 · 0.0% own

MEXER$5

Huang James · Director, 10%…Nov 28, 2025

48,737 sh @ $0.0001

SSELL$739

Nguyen AnhCo · President and CEONov 17, 2025

56 sh @ $13.19 · <0.1% own

SSELL$37.7K

Nguyen AnhCo · President and CEONov 17, 2025

2,859 sh @ $13.19 · -4.2% own

SSELL$976

Grant-Huerta Yanina · Chief Accounting…Nov 17, 2025

74 sh @ $13.19 · -0.2% own

SSELL$1.1K

Grant-Huerta Yanina · Chief Accounting…Nov 17, 2025

85 sh @ $13.19 · -0.3% own

SSELL$21.7K

Grant-Huerta Yanina · Chief Accounting…Nov 17, 2025

1,645 sh @ $13.19 · -4.7% own

SSELL$18.8K

Nguyen AnhCo · President and CEOAug 18, 2025

1,620 sh @ $11.62 · -2.3% own

SSELL$14.9K

Nguyen AnhCo · President and CEOAug 18, 2025

1,281 sh @ $11.62 · -1.8% own

SSELL$662

Nguyen AnhCo · President and CEOAug 18, 2025

57 sh @ $11.61 · <0.1% own

SSELL$19.4K

Grant-Huerta Yanina · Chief Accounting…Aug 18, 2025

1,668 sh @ $11.61 · -4.5% own

SSELL$999

Grant-Huerta Yanina · Chief Accounting…Aug 18, 2025

86 sh @ $11.61 · -0.2% own

SSELL$639

Grant-Huerta Yanina · Chief Accounting…Aug 18, 2025

55 sh @ $11.61 · -0.1% own

PBUY▲$670.4K

Huang James · Director, 10%…Aug 15, 2025

55,000 sh @ $12.19 · +4.1% own

PBUY$186.4K

Huang James · Director, 10%…Jul 17, 2025

19,335 sh @ $9.64 · +1.5% own

AGRANT—

Gallagher Carol Giltner · DirectorJun 10, 2025

7,828 sh · +31.1% own

AGRANT—

Fust Matthew K · DirectorJun 10, 2025

7,828 sh · +75.6% own

AGRANT—

Touchon Pascal · DirectorJun 10, 2025

7,828 sh · +11.2% own

AGRANT—

Roncarolo Maria Grazia · DirectorJun 10, 2025

7,828 sh · +82.0% own

AGRANT—

Mallik Ameet · DirectorJun 10, 2025

7,828 sh · +86.0% own

AGRANT—

Heiden William K · DirectorJun 10, 2025

7,828 sh · +54.5% own

AGRANT◆$1.5M

Adiumentum Capital Fund… · Director, 10%…May 16, 2025

227,000 sh @ $6.61

AGRANT$499.5K

Adiumentum Capital Fund… · Director, 10%…May 16, 2025

75,572 sh @ $6.61 · +6.7% own

SSELL$15K

Grant-Huerta Yanina · Chief Accounting…May 16, 2025

2,218 sh @ $6.76 · -5.7% own

SSELL$22.2K

Nguyen AnhCo · President and CEOMay 16, 2025

3,276 sh @ $6.76 · -4.4% own

Filing record

How quickly insiders here report their trades. Section 16 allows two business days from the transaction.

1 of 32 filings we hold was filed after the two-business-day deadline. The furthest past the deadline was 5 business days late.

Form 4 filings made after the two-business-day deadline, with the transaction date, the filing date and the number of business days between them.
Traded	Filed	Insider	Past deadline	Largest line	Source
Aug 17	Aug 26	Nguyen AnhCoPresident and CEO	5days	$40.9K	Filing ↗

Nguyen AnhCoPresident and CEO

5days

Traded Aug 17 · filed Aug 26Filing ↗

Counted in business days from the transaction date, or the deemed execution date where the filing reports one, excluding weekends and federal holidays. How this is measured · All late filings

Insiders at this company

Everyone who has filed a Form 4 for this issuer.

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