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 35 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	$17.82M 1,552,000 shares	0.88%	+1.45M(+1,458.30%)Added	SEC filing ↗ Aug 14, 2026	▾
02	ADAGE CAPITAL PARTNERS GP, L.L.C. CIK 1165408 · View history	$9.76M 850,000 shares	0.01%	+150.00K(+21.40%)Added	SEC filing ↗ Aug 14, 2026	▾
03	Point72 Asset Management, L.P. CIK 1603466 · View history	$7.90M 687,718 shares	0.01%	+493.45K(+254.00%)Added	SEC filing ↗ Aug 14, 2026	▾
04	Redmile Group, LLC CIK 1425738 · View history	$5.07M 441,701 shares	0.34%	0(0.00%)Unchanged	SEC filing ↗ Aug 14, 2026	▾
05	VANGUARD CAPITAL MANAGEMENT LLC CIK 2100119 · View history	$2.84M 247,047 shares	0.00%	+29.18K(+13.40%)Added	SEC filing ↗ Aug 13, 2026	▾
06	MACKENZIE FINANCIAL CORP CIK 919859 · View history	$2.68M 233,249 shares	0.00%	-80.37K(-25.60%)Reduced	SEC filing ↗ Aug 13, 2026	▾
07	BlackRock, Inc. CIK 2012383 · View history	$969.54K 84,455 shares	0.00%	+5.43K(+6.90%)Added	SEC filing ↗ Aug 7, 2026	▾
08	GEODE CAPITAL MANAGEMENT, LLC CIK 1214717 · View history	$862.92K 75,128 shares	0.00%	+8.98K(+13.60%)Added	SEC filing ↗ Aug 12, 2026	▾
09	STALEY CAPITAL ADVISERS INC CIK 1106565 · View history	$574.00K 50,000 shares	0.02%	0(0.00%)Unchanged	SEC filing ↗ Aug 11, 2026	▾
10	VANGUARD FIDUCIARY TRUST CO CIK 933478 · View history	$494.05K 43,036 shares	0.00%	+9.41K(+28.00%)Added	SEC filing ↗ Aug 13, 2026	▾
11	ACADIAN ASSET MANAGEMENT LLC CIK 916542 · View history	$444.00K 38,845 shares	0.00%	-92.06K(-70.30%)Reduced	SEC filing ↗ Aug 13, 2026	▾
12	JANE STREET GROUP, LLC CIK 1595888 · View history	$348.36K 30,345 shares	0.00%	-3.52K(-10.40%)Reduced	SEC filing ↗ Aug 14, 2026	▾
13	STATE STREET CORP CIK 93751 · Amended · View history	$303.68K 26,453 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Sep 22, 2026	▾
14	NORTHERN TRUST CORP CIK 73124 · View history	$190.47K 16,591 shares	0.00%	+4.25K(+34.40%)Added	SEC filing ↗ Aug 13, 2026	▾
15	FMR LLC CIK 315066 · View history	$186.41K 16,238 shares	0.00%	0(0.00%)Unchanged	SEC filing ↗ Aug 13, 2026	▾
16	XTX Topco Ltd CIK 1828301 · View history	$175.68K 15,303 shares	0.00%	+15.30KNew	SEC filing ↗ Aug 14, 2026	▾
17	BRIDGEWAY CAPITAL MANAGEMENT, LLC CIK 1107261 · View history	$160.72K 14,000 shares	0.00%	-18.69K(-57.20%)Reduced	SEC filing ↗ Aug 14, 2026	▾
18	MILLENNIUM MANAGEMENT LLC CIK 1273087 · View history	$145.57K 12,680 shares	0.00%	-35.01K(-73.40%)Reduced	SEC filing ↗ Aug 14, 2026	▾
19	CITADEL ADVISORS LLC CIK 1423053 · Amended · View history	$116.63K 10,159 shares	0.00%	+10.16KNew	SEC filing ↗ Sep 2, 2026	▾
20	MORGAN STANLEY CIK 895421 · View history	$105.37K 9,178 shares	0.00%	+9(+0.10%)Added	SEC filing ↗ Aug 13, 2026	▾

Showing 20 / 35 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions

Cancelled or null records excluded

Disclosed shares

4,467,954

Not deduplicated across managers

Disclosed value

$51.29M

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. · Q2 2026

Explore all 35 reporting institutions.

This page includes 20 of 35 reporting institutions. Log in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and get the complete set through the Akkru API.

Download CSV
Earlier quarters
Advanced screening & filtering
API & AI access

Already have an account?

＋ New accounts get free API credits to explore data beyond ownership filings.

For AI agents & developers

The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. This page lists 20 of 35 reporting institutions; totals use the complete disclosed data.

Without an account: the last 3 years, with the row caps stated on the page. A free account opens all history on file on these pages and the CSV of what a page shows. Rows beyond the caps and bulk retrieval go through the authenticated API / MCP / CLI.

MCP  https://api.akkrudata.ai/mcp

akkru_institutional_holdings
{"action":"holders","cusip":"046513206","quarter":"2026Q2","type":"positions","page_size":100}

Connect to MCP with OAuth and follow the returned pagination. Credits and usage limits depend on the account.

MCP endpoint: https://api.akkrudata.ai/mcp
API / MCP / CLI documentation: /documents
llms.txt: /llms.txt

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.