Company · Ownership research

Atara Biotherapeutics, Inc. ATRA

CIK 0001604464 · CUSIP 046513206

Insider trading Initial holdings Institutional holders

Quarter-end disclosures, not live holdings.

Several CUSIPs are reported for this company; this page shows CUSIP 046513206 (ATRA), not CUSIP 046513107 (ATRA), and does not merge CUSIPs.

This page lists the top 20 of 36 rows by value; the complete set is available through the API.

Some filings reported values in thousands; those figures were scaled ×1,000 to dollars.

Top 20 institutions

Weight means this stock's share of the manager's own portfolio.

By reported value

#	Manager	Value	Manager weight	Change vs prior	Source
01	EcoR1 Capital, LLC CIK 1587114 · View history	$8.21M 573,183 shares	0.39%	0(0.00%)Unchanged	SEC filing ↗ Nov 14, 2025	▾
02	Redmile Group, LLC CIK 1425738 · View history	$6.33M 441,701 shares	0.62%	0(0.00%)Unchanged	SEC filing ↗ Nov 14, 2025	▾
03	VANGUARD GROUP INC CIK 102909 · View history	$2.92M 203,438 shares	0.00%	+12.68K(+6.60%)Added	SEC filing ↗ Nov 7, 2025	▾
04	MARSHALL WACE, LLP CIK 1318757 · View history	$1.66M 115,796 shares	0.00%	+73.44K(+173.40%)Added	SEC filing ↗ Nov 13, 2025	▾
05	BlackRock, Inc. CIK 2012383 · View history	$1.00M 69,833 shares	0.00%	-1.01K(-1.40%)Reduced	SEC filing ↗ Nov 12, 2025	▾
06	MACKENZIE FINANCIAL CORP CIK 919859 · View history	$914.48K 63,816 shares	0.00%	+41.30K(+183.50%)Added	SEC filing ↗ Nov 13, 2025	▾
07	GEODE CAPITAL MANAGEMENT, LLC CIK 1214717 · View history	$867.50K 60,526 shares	0.00%	+390(+0.60%)Added	SEC filing ↗ Nov 12, 2025	▾
08	ACADIAN ASSET MANAGEMENT LLC CIK 916542 · View history	$807.00K 56,416 shares	0.00%	-8.74K(-13.40%)Reduced	SEC filing ↗ Nov 13, 2025	▾
09	STALEY CAPITAL ADVISERS INC CIK 1106565 · View history	$716.50K 50,000 shares	0.03%	-25.00K(-33.30%)Reduced	SEC filing ↗ Nov 12, 2025	▾
10	MORGAN STANLEY CIK 895421 · Amended · View history	$514.99K 35,938 shares	0.00%	+21.01K(+140.80%)Added	SEC filing ↗ May 27, 2026	▾
11	GSA CAPITAL PARTNERS LLP CIK 1362033 · View history	$376.00K 26,213 shares	0.03%	+6.62K(+33.80%)Added	SEC filing ↗ Nov 7, 2025	▾
12	STATE STREET CORP CIK 93751 · View history	$361.88K 25,253 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Nov 14, 2025	▾
13	JANE STREET GROUP, LLC CIK 1595888 · View history	$316.12K 22,060 shares	0.00%	+22.06KNew	SEC filing ↗ Nov 14, 2025	▾
14	RENAISSANCE TECHNOLOGIES LLC CIK 1037389 · View history	$271.35K 18,936 shares	0.00%	+2.00K(+11.80%)Added	SEC filing ↗ Nov 13, 2025	▾
15	UBS Group AG CIK 1610520 · View history	$247.45K 17,268 shares	0.00%	+8.88K(+105.90%)Added	SEC filing ↗ Nov 13, 2025	▾
16	FMR LLC CIK 315066 · View history	$245.84K 17,156 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Nov 13, 2025	▾
17	Cambridge Investment Research Advisors, Inc. CIK 1419186 · View history	$245.00K 17,109 shares	0.00%	+17.11KNew	SEC filing ↗ Nov 12, 2025	▾
18	Quadrature Capital Ltd CIK 1651424 · View history	$236.88K 16,542 shares	0.00%	+16.54KNew	SEC filing ↗ Nov 13, 2025	▾
19	GLOBEFLEX CAPITAL L P CIK 921531 · View history	$221.51K 15,458 shares	0.03%	+15.46KNew	SEC filing ↗ Nov 12, 2025	▾
20	BRIDGEWAY CAPITAL MANAGEMENT, LLC CIK 1107261 · View history	$200.62K 14,000 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Nov 14, 2025	▾

Showing 20 / 36 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions

Cancelled or null records excluded

Disclosed shares

1,883,136

Not deduplicated across managers

Disclosed value

$26.98M

Not market cap or free float

Reporting institutions by quarter

Counts also change with data coverage and reporting entities; they do not measure net buying. Distinct managers with a live stock row in this CUSIP; totals may include overlapping filings and are not a share of the company.

Atara Biotherapeutics, Inc. · Q3 2025

Explore all 36 reporting institutions.

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Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.