ATRA · Atara Biotherapeutics, Inc.

$9.44 +0.42 (+4.66%) At close · Sep 2

Market Cap

$94.76M

10.04M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Quarter:

Holders: 37

Total Value: $51,294,706

Total Shares: 4,468,182

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 37 13F filers · Δ vs Mar 31, 2026

Top Holder

34.7%

+7.4 pts

Top 5

84.6%

+11.7 pts

Top 10

95.4%

+6.0 pts

HHI

1,972

Moderately concentrated+575

Quarterly Activity

vs Mar 31, 2026

New

Increased

Decreased

Sold Out

Unchanged

Holder count: +2

Institutional value: +322.9%

Shares held: +74.2%

Top Buyers

vs Mar 31, 2026

Institution	Added	Now Holds
Mid EcoR1 Capital, LLC	+1,452,407	1,552,000
Large Point72 Asset Management, L.P.	+493,454	687,718
Large ADAGE CAPITAL PARTNERS GP, L.L.C.	+150,000	850,000
Mega VANGUARD CAPITAL MANAGEMENT LLC	+29,185	247,047
Mega VANGUARD FIDUCIARY TRUST CO	+9,415	43,036

Top Sellers

vs Mar 31, 2026

Institution	Sold	Now Holds
Large ACADIAN ASSET MANAGEMENT LLC	−92,065	38,845
Large MACKENZIE FINANCIAL CORP	−80,371	233,249
Mega UBS Group AG	−46,091	3,979
Mega MILLENNIUM MANAGEMENT LLC	−35,009	12,680
Mid BRIDGEWAY CAPITAL MANAGEMENT, LLC	−18,691	14,000

Top New Positions

vs Mar 31, 2026

Institution	Acquired	Value (USD)
Mid XTX Topco Ltd	15,303	$175,678
Mega CITADEL ADVISORS LLC	10,159	$116,625
Small Caitong International Asset Management Co., Ltd	311	$3,570
Mega BARCLAYS PLC	304	$3,489

Top Sold-Out Positions

vs Mar 31, 2026

Institution	Previously Held	Last Value (USD)	Open
Mega RHUMBLINE ADVISERS	175	$827
Mid Western Wealth Management, LLC	1	$4

Filter: New 4 Increased 12 Reduced 8 Sold out 2 Unchanged 13

Showing 37 of 37

All Common Calls Puts

Compact Export CSV

Holder

Value (USD)

% of 13F

EcoR1 Capital, LLC

$17,816,960

34.73%

1,552,000

ADAGE CAPITAL PARTNERS GP, L.L.C.

$9,758,000

19.02%

850,000

Point72 Asset Management, L.P.

$7,895,002

15.39%

687,718

Redmile Group, LLC

$5,070,727

9.89%

441,701

VANGUARD CAPITAL MANAGEMENT LLC

$2,836,099

5.53%

247,047

MACKENZIE FINANCIAL CORP

$2,677,698

5.22%

233,249

BlackRock, Inc.

$969,541

1.89%

84,455

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BLACKROCK FINANCIAL MANAGEMENT INC/DE	10,260	$117,784	12.1%	Sole
BlackRock Investment Management, LLC	1,147	$13,167	1.4%	Sole
BlackRock Fund Advisors	17,227	$197,765	20.4%	Sole
BlackRock Institutional Trust Company, N.A.	55,821	$640,825	66.1%	Sole

GEODE CAPITAL MANAGEMENT, LLC

$862,468

1.68%

75,128

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
GEODE CAPITAL MANAGEMENT TRUST COMPANY, LLC	12,364	$141,938	16.5%	Defined
Held directly	62,764	$720,530	83.5%	Defined

STALEY CAPITAL ADVISERS INC

$574,000

1.12%

50,000

VANGUARD FIDUCIARY TRUST CO

$494,053

0.96%

43,036

ACADIAN ASSET MANAGEMENT LLC

$445,940

0.87%

38,845

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Acadian Inc	38,845	$445,940	100.0%	Defined

JANE STREET GROUP, LLC

$348,360

0.68%

30,345

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Jane Street Capital, LLC	30,336	$348,257	100.0%	Defined
Jane Street Global Trading, LLC	9	$103	0.0%	Defined

STATE STREET CORP

$303,680

0.59%

26,453

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
STATE STREET GLOBAL ADVISORS TRUST COMPANY	26,453	$303,680	100.0%	Defined

NORTHERN TRUST CORP

$190,464

0.37%

16,591

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
NORTHERN TRUST CO joint	16,591	$190,464	100.0%	Defined

FMR LLC

$186,412

0.36%

16,238

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Fidelity Management & Research Co LLC	16,238	$186,412	100.0%	Defined

XTX Topco Ltd

$175,678

0.34%

15,303

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
XTX EXECUTION SERVICES LLC joint	15,303	$175,678	100.0%	Defined

BRIDGEWAY CAPITAL MANAGEMENT, LLC

$160,720

0.31%

14,000

MILLENNIUM MANAGEMENT LLC

$145,566

0.28%

12,680

CITADEL ADVISORS LLC

$116,625

0.23%

10,159

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citadel Securities GP LLC	10,123	$116,212	99.6%	Defined
Held directly	36	$413	0.4%	Defined

MORGAN STANLEY

$105,360

0.21%

9,178

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
MORGAN STANLEY & CO. LLC	4	$45	0.0%	Defined
MORGAN STANLEY CAPITAL SERVICES, LLC	9,002	$103,342	98.1%	Defined
MORGAN STANLEY SMITH BARNEY LLC	167	$1,916	1.8%	Defined
PARAMETRIC PORTFOLIO ASSOCIATES LLC	5	$57	0.1%	Defined

ROYAL BANK OF CANADA

$54,449

0.11%

4,743

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
RBC Capital Markets, LLC	1,093	$12,547	23.0%	Defined
BREWIN DOLPHIN WEALTH MANAGEMENT LTD	3,650	$41,902	77.0%	Defined

UBS Group AG

$45,678

0.09%

3,979

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
UBS AG	3,514	$40,340	88.3%	Defined
UBS Securities LLC	465	$5,338	11.7%	Defined

Vanguard Global Advisers, LLC

$16,714

0.03%

1,456

SBI Securities Co., Ltd.

$16,117

0.03%

1,404

JONES FINANCIAL COMPANIES LLLP

$9,218

0.02%

803

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Edward D. Jones & Co., L.P.	803	$9,218	100.0%	Sole

Caitong International Asset Management Co., Ltd

$3,570

0.01%

311

BARCLAYS PLC

$3,489

0.01%

304

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
BARCLAYS CAPITAL INC.	304	$3,489	100.0%	Defined

WELLS FARGO & COMPANY/MN

$2,881

0.01%

251

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
WELLS FARGO CLEARING SERVICES, LLC	251	$2,881	100.0%	Defined

JPMORGAN CHASE & CO

$2,479

0.00%

216

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
J.P. Morgan Securities LLC	100	$1,148	46.3%	Defined
J.P. Morgan Securities plc	116	$1,331	53.7%	Defined

Raiffeisen Bank International AG

$2,296

0.00%

200

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Limited Liability Co Raiffeisen Capital Management Co	200	$2,296	100.0%	Sole

Banque Transatlantique SA

$2,020

0.00%

176

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Caisse Federale de Credit Mutuel	176	$2,020	100.0%	Defined

CITIGROUP INC

$1,113

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
Citigroup Financial Products Inc. joint	97	$1,113	100.0%	Defined

BNP PARIBAS ARBITRAGE, SA

$528

0.00%

PlanVest Financial, Inc

$321

0.00%

KERR FINANCIAL PLANNING Corp

$275

0.00%

OSAIC HOLDINGS, INC.

$114

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
OSAIC WEALTH, INC.	10	$114	100.0%	Defined

Rockefeller Capital Management L.P.

$91

0.00%

This filing is a combination report: the position is filed across the managers below.

Manager	Shares	Value (USD)	% of position	Discretion
ROCKEFELLER FINANCIAL LLC	8	$91	100.0%	Defined

Key facts CIK 1604464 CUSIP 046513206 13F (30d) 33 filings 32 filers Visit website Investor relations