How many institutional investors hold ATRA?

1 tracked institutional investor disclosed a position in ATRA (ATARA BIOTHERAPEUTICS INC) in their most recent 13F filing.

Who is the largest institutional holder of ATRA?

Ken Griffin, Citadel Advisors, holds the largest disclosed position in ATRA, valued at $281,788.

Did institutional ownership of ATRA increase or decrease?

Across recent 13F filings, tracked investors recorded 0 new positions, 0 increased, 0 reduced, and 0 fully exited ATRA.

Where does this ATRA ownership data come from?

SEC Form 13F-HR filings, accessed via EDGAR. 13F filings are disclosed quarterly with a 45-day reporting delay and cover U.S.-listed long equity positions only. This is not investment advice.

ATRA — ATARA BIOTHERAPEUTICS INC

Name: ATARA BIOTHERAPEUTICS INC (ATRA) — Institutional Ownership
Creator: InvestorLens
License: https://www.sec.gov/about/website-policies

Public company

For educational research only.InvestorLens analyzes public regulatory filings (SEC EDGAR, STOCK Act PTRs) that may be delayed by 45 days or more. Information shown is historical and is not financial, legal, or tax advice, nor a recommendation or solicitation to buy or sell any security. Always do your own research.

InvestorLens aggregates public filing data to show which tracked investors reported holdings in this stock. Dollar values represent reported position values, not market capitalization, and may be delayed up to 45 days. Not a recommendation.

Sourced from SEC EDGAR public filings

About ATARA BIOTHERAPEUTICS INC (ATRA)

ATARA BIOTHERAPEUTICS INC (ATRA) appears in the most recent 13F filings of 1 tracked institutional investor. The largest disclosed position is held by Ken Griffin (Citadel Advisors), valued at $281,788. All data sourced from SEC 13F filings.

Tracked investors reporting ATRA

Investor	Firm	Shares	Market value	% of portfolio	As of
Ken Griffin	Citadel Advisors	15.6K	$281.8K	0.00%	Dec 31, 2025

Ken GriffinDec 31, 2025
Citadel Advisors
Shares
15.6K
Value
$281.8K
% Portfolio
0.00%

Recent activity

Investor	Action	Δ %	Current value	Filing date
No recent activity.

No recent activity.

Frequently asked questions

How many institutional investors hold ATRA?: 1 tracked institutional investor disclosed a position in ATRA (ATARA BIOTHERAPEUTICS INC) in their most recent 13F filing.
Who is the largest institutional holder of ATRA?: Ken Griffin, Citadel Advisors, holds the largest disclosed position in ATRA, valued at $281,788.
Did institutional ownership of ATRA increase or decrease?: Across recent 13F filings, tracked investors recorded 0 new positions, 0 increased, 0 reduced, and 0 fully exited ATRA.
Where does this ATRA ownership data come from?: SEC Form 13F-HR filings, accessed via EDGAR. 13F filings are disclosed quarterly with a 45-day reporting delay and cover U.S.-listed long equity positions only. This is not investment advice.