Panacea Innovation Ltd - 07 May 2026 Form 4 Insider Report for Atara Biotherapeutics, Inc. (ATRA)

Reporting relationship: 10%+ Owner
Issuer ticker: ATRA
Reported as of: 07 May 2026
Net transaction value: -$3,165,021
SEC form: 4
Accepted by SEC: 11 May 2026, 18:45:04 UTC
Prior SEC filing: 19 Mar 2026
Source filing: View source filing
Reporting owner signature: Panacea Innovation Limited By: /s/ James Huang, Founding Managing Partner

Key filing fact

Panacea Innovation Ltd filed Form 4 for Atara Biotherapeutics, Inc. (ATRA) on 11 May 2026.

Key facts

This page summarizes Panacea Innovation Ltd's Form 4 filing for Atara Biotherapeutics, Inc. (ATRA).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 11 May 2026, 18:45.

Change

Previous filing in this sequence was filed on 19 Mar 2026.
Current net transaction value: -$3,165,021.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (2)

CIK 0002010692 Primary reporting owner

Panacea Innovation Ltd

Relationship: 10%+ Owner
Address: C/O PANACEA CAPITAL, 79 SCIENCE PARK DRIVE, #04-05, SINGAPORE, SINGAPORE
Signature: Panacea Innovation Limited By: /s/ James Huang, Founding Managing Partner
Signature date: 11 May 2026

CIK 0001573160

Huang James

Relationship: Director, 10%+ Owner
Address: C/O PANACEA CAPITAL, 79 SCIENCE PARK DRIVE, #04-05, SINGAPORE, SINGAPORE
Signature: /s/ James Huang
Signature date: 11 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ATRA transaction

Common Stock

Sale

Transaction value: $3,165,021
Shares: -313,446
Change %: -24%
Price: $10.10
Shares after: 1,011,000
Date: 07 May 2026
Ownership: See Footnote
Footnotes: F1, F2, F3

ATRA transaction

Common Stock

Sale

Transaction value: $3,165,021
Shares: -313,446
Change %: -24%
Price: $10.10
Shares after: 1,011,000
Date: 07 May 2026
Ownership: See Footnote
Footnotes: F1, F2, F3

ATRA holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 307,894
Date: 07 May 2026
Ownership: See Footnotes
Footnotes: F3, F4

ATRA holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 307,894
Date: 07 May 2026
Ownership: See Footnotes
Footnotes: F3, F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 4 footnotes

Footnote F1

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $10.00 to $10.50, inclusive. The Reporting Person undertake to provide to the Issuer, any securityholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.

Footnote F2

Represents securities held by Panacea Venture Healthcare Fund II, L.P.

Footnote F3

James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. ("Fund II GP") and Panacea Opportunity Fund I GP Company, Ltd. ("Opportunity Fund GP"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. As a result, each of the Reporting Persons may be deemed to share beneficial ownership of the securities held of record by Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., but each disclaims such beneficial ownership.

Footnote F4

Represents securities held by Panacea Opportunity Fund I, L.P.