Atara Biotherapeutics, Inc. (ATRA) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

13,564,000Shares Outstanding

2,049,863Shares held by institutions

$10,802,778Value of institutional holdings

15.11%Institutional ownership %

10.04%Shares Changed QoQ

41No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

Atara Biotherapeutics, Inc. (NASDAQ:ATRA) has 41 institutional investors with active 13F positions as of December 2025.

They owned 15.1% of outstanding stock in December 2025, up from 13.9% the prior quarter.
They increased total shares held in Atara Biotherapeutics by 10.04% from the prior quarter, while the number of investors in ATRA decreased 2.38% year over year.
Among the 41 funds, 19 bought more Atara Biotherapeutics shares, 10 sold down, and 12 held their ground.
Altogether, these fund groups held 2.05Mn shares in ATRA by December 2025, up by 187.02K shares quarter on quarter, and down 369.95K shares year over year.
EcoR1 Capital, LLC holds the largest position in ATRA at 573.18K shares as of December 31, 2025, or 4.23% of shares outstanding.
The most significant purchases of ATRA for the quarter ending December 2025 came from GLOBEFLEX CAPITAL L P (61.77K), MARSHALL WACE, LLP (32.84K), VANGUARD GROUP INC (22.5K), BRIDGEWAY CAPITAL MANAGEMENT, LLC (18.69K), Point72 Asset Management, L.P. (18.3K).
The largest sellers of Atara Biotherapeutics for the quarter ending December 2025 were Morgan Stanley (19.95K), UBS Group AG (15.87K), JANE STREET GROUP, LLC (8.07K), MACKENZIE FINANCIAL CORP (5.15K), BlackRock, Inc. (2.72K).
Business Quant data shows the 10 biggest positions in Atara Biotherapeutics as of December 2025 are held by EcoR1 Capital, LLC (573.18K), Redmile Group, LLC (441.7K), VANGUARD GROUP INC (225.94K), MARSHALL WACE, LLP (148.63K), GLOBEFLEX CAPITAL L P (77.22K), BlackRock, Inc. (67.11K), GEODE CAPITAL MANAGEMENT, LLC (62.38K), MACKENZIE FINANCIAL CORP (58.67K), ACADIAN ASSET MANAGEMENT LLC (54.05K), STALEY CAPITAL ADVISERS INC (50.0K).

41 Institutional Holders

2,049,863 Total Shares Held

Rows:

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Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
EcoR1 Capital, LLC	31 Dec, 2025	573,183	0	0.00%	$10,368,880.00
Redmile Group, LLC	31 Dec, 2025	441,701	0	0.00%	$7,990,371.00
VANGUARD GROUP INC	31 Dec, 2025	225,940	22,502	11.06%	$4,087,255.00
MARSHALL WACE, LLP	31 Dec, 2025	148,632	32,836	28.36%	$2,688,752.00
GLOBEFLEX CAPITAL L P	31 Dec, 2025	77,224	61,766	399.57%	$1,396,982.00
BlackRock, Inc.	31 Dec, 2025	67,108	-2,725	-3.90%	$1,213,984.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	62,381	1,855	3.06%	$1,129,112.00
MACKENZIE FINANCIAL CORP	31 Dec, 2025	58,668	-5,148	-8.07%	$1,046,920.00
ACADIAN ASSET MANAGEMENT LLC	31 Dec, 2025	54,048	-2,368	-4.20%	$976.00
STALEY CAPITAL ADVISERS INC	31 Dec, 2025	50,000	0	0.00%	$904,500.00
BRIDGEWAY CAPITAL MANAGEMENT, LLC	31 Dec, 2025	32,691	18,691	133.51%	$591,380.00
RENAISSANCE TECHNOLOGIES LLC	31 Dec, 2025	30,040	11,104	58.64%	$543,424.00
State Street Corp	31 Dec, 2025	26,453	1,200	4.75%	$478,535.00
Cambridge Investment Research Advisors, Inc.	31 Dec, 2025	22,864	5,755	33.64%	$414.00
Quadrature Capital Ltd	31 Dec, 2025	20,321	3,779	22.84%	$367,607.00
Point72 Asset Management, L.P.	31 Dec, 2025	18,296	18,296	0.00%	$330,975.00
FMR LLC	31 Dec, 2025	17,156	0	0.00%	$310,352.00
Morgan Stanley	31 Dec, 2025	15,991	-19,947	-55.50%	$289,276.00
CITADEL ADVISORS LLC	31 Dec, 2025	15,577	15,577	0.00%	$281,788.00
SUSQUEHANNA INTERNATIONAL GROUP, LLP	31 Dec, 2025	14,018	14,018	0.00%	$253,586.00

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