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Form SCHEDULE 13G/A Atara Biotherapeutics, Filed by: EcoR1 Capital, LLC

May 7, 2026 7:27 PM





Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)




schemaVersion:


SCHEDULE 13G




Comment for Type of Reporting Person: The shares reported herein consist of 1,552,000 shares of Common Stock beneficially owned by the reporting persons, and exclude warrants to acquire 1,090,922 shares of Common Stock, which are subject to a 9.99% beneficial ownership limitation and currently cannot be exercised. The percentage is calculated based on 8,912,272 shares of Common Stock outstanding on May 7, 2026.


SCHEDULE 13G




Comment for Type of Reporting Person: The shares reported herein consist of 1,552,000 shares of Common Stock beneficially owned by the reporting persons, and exclude warrants to acquire 1,090,922 shares of Common Stock, which are subject to a 9.99% beneficial ownership limitation and currently cannot be exercised. The percentage is calculated based on 8,912,272 shares of Common Stock outstanding on May 7, 2026.


SCHEDULE 13G




Comment for Type of Reporting Person: The shares reported herein consist of 1,445,609 shares of Common Stock beneficially owned by the reporting persons, and exclude warrants to acquire 1,026,558 shares of Common Stock, which are subject to a 9.99% beneficial ownership limitation and currently cannot be exercised. The percentage is calculated based on 8,912,272 shares of Common Stock outstanding on May 7, 2026.


SCHEDULE 13G



EcoR1 Capital, LLC
Signature:/s/ Oleg Nodelman
Name/Title:Manager
Date:05/07/2026
Oleg Nodelman
Signature:/s/ Oleg Nodelman
Name/Title:Reporting person
Date:05/07/2026
EcoR1 Capital Fund Qualified, L.P.
Signature:/s/ Oleg Nodelman
Name/Title:Manager of the General Partner, EcoR1 Capital, LLC
Date:05/07/2026
Exhibit Information

Exhibit 99 - Agreement Regarding Joint Filing of Statement on Schedule 13D or 13G

ATTACHMENTS / EXHIBITS

AGREEMENT REGARDING JOINT FILING

Categories

SEC Filings