SCHEDULE 13D/A Filed 2026-05-11 Event 2026-05-07 SEC 0001193125-26-217389 →

Panacea Innovation Ltd → Atara Biotherapeutics, Inc. ATRA

Stake: — Shares: 1,318,894 Class: Common Stock

Item 4 — Purpose of Transaction

Not extracted from this filing — typically because it's an amendment (13D/A) and Item 4 is unchanged from the parent filing. Read the raw SEC filing →

Cross-References

Insider Activity (last 365d)

6 transactions

0 buys · 1 sales · 4 awards/exercises

Issuer Cluster

3 13D/G filings on this issuer

2 other filings besides this one

Filer Track Record

4 filings by this filer

3 other filings in the data moat

Short Interest · settle 2026-09-30

DTC 8.11

321,792 shares short · -20.4% vs prior

Institutional Consensus · 2025-12-31

Held by elite portfolio managers

1 holder · $331K

Point72 Asset Mgmt

Post-Filing Returns · since 2026-05-07 on ATRA

+1 day

-16.0%

+5 days

-1.2%

+30 days

-3.5%

+60 days

+9.6%

+90 days

—

+180 days

—

Anchor price 9.93 on closest trading day on/after 2026-05-07. Source: Yahoo Finance daily adj_close (split + dividend adjusted).

Form 4 Insider Transactions · last 365d

Date	Insider	Role	Type	Shares	Price	Value
2026-08-17	Nguyen AnhCo	director, officer	Sale	5,062	$8.08	$41K
2026-07-22	Redmile Group, LLC	director	Option exercise	195,211	—	—
2026-07-22	Redmile Group, LLC	director	F	60	—	—
2026-07-22	Redmile Group, LLC	director	Option exercise	101,089	$0.00	$253
2026-07-22	Redmile Group, LLC	director	Option exercise	38,735	$0.00	$97
2026-07-22	Redmile Group, LLC	director	Option exercise	55,387	$0.00	$138

Other 13D/G Filings on Atara Biotherapeutics, Inc.

Filed	Form	Filer	Stake	Shares
2026-07-24	SCHEDULE 13D/A	Redmile Group, LLC	9.90%	950,994	view →
2026-05-14	SCHEDULE 13D/A	Redmile Group, LLC	9.90%	950,994	view →

Other Filings by Panacea Innovation Ltd

Filed	Form	Issuer	Stake	Shares
2026-04-01	SCHEDULE 13D/A	Connect Biopharma Holdings Limited CNTB	21.20%	13,160,000	view →
2025-07-21	SCHEDULE	Connect Biopharma Holdings Ltd CNTB	25.10%	13,950,000	view →
2024-07-01	SC	Connect Biopharma Holdings Ltd CNTB	—	—	view →

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