Atara Biotherapeutics ATRA Institutional Ownership

NASDAQ ATRA

$9.89 -0.02 (-0.20%)

At close: Sep 10, 2026 · 4:00 PM EDT

Institutions by Trading Activity

35 Institutions

Increased 16 45.7%

Unchanged 11 31.4%

Reduced 8 22.9%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

29.72%

▲+11.51 pp QoQ

Shares Held by Institutions

4.47Mn

of 15.03Mn outstanding

▲+74.25% QoQ

Shares Outstanding

15.03Mn

10.57Mn held outside 13F filers

Institutional Investors

filed 13F for Jun 2026

▲+1 vs prior quarter

Net Shares Added (QoQ)

+1.90Mn

accumulated since last quarter

Value of Holdings

$43.61Mn

reported market value

Shares Owned by Institutions

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Institutions

Accumulated Distributed

Latest quarter —

Net over range —

Accumulating quarters —

Ownership Summary

Quarter ending 30 Jun, 2026

Atara Biotherapeutics, Inc. (NASDAQ:ATRA) showed up in the 13F filings of 35 institutional investors as of June 2026.

These investors held 29.7% of outstanding shares in June 2026, up from 18.2% in March 2026.
They increased total shares held in ATRA by 74.25% quarter over quarter, and investors in Atara Biotherapeutics increased 12.9% from a year ago.
Of these 35 funds, 16 grew their exposure to Atara Biotherapeutics, 8 cut back, and 11 maintained positions.
Altogether, these fund groups held 4.47Mn shares in ATRA by June 2026, up by 1.9Mn shares quarter on quarter, and up 2.7Mn shares year over year.
As of June 30, 2026, the biggest holder of Atara Biotherapeutics is EcoR1 Capital, LLC at 1.55Mn shares, representing 10.32% of shares outstanding.
Top purchasers of ATRA stock for the quarter ending June 2026 included EcoR1 Capital, LLC (1.45Mn), Point72 Asset Management, L.P. (493.45K), ADAGE CAPITAL PARTNERS GP, L.L.C. (150.0K), VANGUARD CAPITAL MANAGEMENT LLC (29.18K), XTX Topco Ltd (15.3K).
Leading sellers of Atara Biotherapeutics shares for the quarter ending June 2026 were ACADIAN ASSET MANAGEMENT LLC (92.06K), MACKENZIE FINANCIAL CORP (80.37K), UBS Group AG (46.09K), MILLENNIUM MANAGEMENT LLC (35.01K), BRIDGEWAY CAPITAL MANAGEMENT, LLC (18.69K).
Per Business Quant, the top 10 investors in ATRA for the quarter ending June 2026 include EcoR1 Capital, LLC (1.55Mn), ADAGE CAPITAL PARTNERS GP, L.L.C. (850.0K), Point72 Asset Management, L.P. (687.72K), Redmile Group, LLC (441.7K), VANGUARD CAPITAL MANAGEMENT LLC (247.05K), MACKENZIE FINANCIAL CORP (233.25K), BlackRock, Inc. (84.46K), GEODE CAPITAL MANAGEMENT, LLC (75.13K), STALEY CAPITAL ADVISERS INC (50.0K), VANGUARD FIDUCIARY TRUST CO (43.04K).

Form 13F Holdings

35 Institutional Holders

Report period 30 Jun, 2026

Total shares held 4.47Mn

Of outstanding 29.72%

#	Institution	CIK	Shares Held	% of Outstanding	Change (QoQ)	Change (%)	Value (USD)
1	EcoR1 Capital, LLC	0001587114	1,552,000	10.32%	▲1,452,407	+1,458.34%	$17.82Mn
2	ADAGE CAPITAL PARTNERS GP, L.L.C.	0001165408	850,000	5.65%	▲150,000	+21.43%	$9.76Mn
3	Point72 Asset Management, L.P.	0001603466	687,718	4.57%	▲493,454	+254.01%	$7.90Mn
4	Redmile Group, LLC	0001425738	441,701	2.94%	0	0.00%	$5.07Mn
5	VANGUARD CAPITAL MANAGEMENT LLC	0002100119	247,047	1.64%	▲29,185	+13.40%	$2.84Mn
6	MACKENZIE FINANCIAL CORP	0000919859	233,249	1.55%	▼80,371	-25.63%	$2.68Mn
7	BlackRock, Inc.	0002012383	84,455	0.56%	▲5,433	+6.88%	$969.54K
8	GEODE CAPITAL MANAGEMENT, LLC	0001214717	75,128	0.50%	▲8,982	+13.58%	$862.92K
9	STALEY CAPITAL ADVISERS INC	0001106565	50,000	0.33%	0	0.00%	$574.00K
10	VANGUARD FIDUCIARY TRUST CO	0000933478	43,036	0.29%	▲9,415	+28.00%	$494.05K
11	ACADIAN ASSET MANAGEMENT LLC	0000916542	38,845	0.26%	▼92,065	-70.33%	$444
12	JANE STREET GROUP, LLC	0001595888	30,345	0.20%	▼3,525	-10.41%	$348.36K
13	State Street Corp	0000093751	26,453	0.18%	0	0.00%	$303.68K
14	Northern Trust Corp	0000073124	16,591	0.11%	▲4,251	+34.45%	$190.47K
15	FMR LLC	0000315066	16,238	0.11%	0	0.00%	$186.41K
16	XTX Topco Ltd	0001828301	15,303	0.10%	▲15,303	0.00%	$175.68K
17	BRIDGEWAY CAPITAL MANAGEMENT, LLC	0001107261	14,000	0.09%	▼18,691	-57.17%	$160.72K
18	MILLENNIUM MANAGEMENT LLC	0001273087	12,680	0.08%	▼35,009	-73.41%	$145.57K
19	CITADEL ADVISORS LLC	0001423053	10,159	0.07%	▲10,159	0.00%	$116.63K
20	Morgan Stanley	0000895421	9,178	0.06%	▲10	+0.11%	$105.37K

Showing 1 to 20 of 35 holders