SCHEDULE 13D/A Filed 2026-05-14 Event 2026-05-12 SEC 0001104659-26-061506 →

Redmile Group, LLC → Atara Biotherapeutics, Inc. ATRA

Stake: 9.90% Shares: 950,994 CUSIP: 046513206 Class: Common Stock, par value $0.0001 per share

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

24 filings by this filer

23 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 2026-05-12 on ATRA

+1 day

+6.8%

+5 days

-6.7%

+30 days

+6.6%

+60 days

-11.6%

+90 days

—

+180 days

—

Anchor price 9.81 on closest trading day on/after 2026-05-12. 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 →
2026-05-11	SCHEDULE 13D/A	Panacea Innovation Ltd	—	1,318,894	view →

Other Filings by Redmile Group, LLC

Filed	Form	Issuer	Stake	Shares
2026-09-28	SCHEDULE 13G	Electra Therapeutics, Inc.	—	—	view →
2026-07-24	SCHEDULE 13D/A	Atara Biotherapeutics, Inc.	9.90%	950,994	view →
2026-07-17	SCHEDULE 13D/A	Shattuck Labs, Inc.	9.90%	10,019,421	view →
2026-06-11	SCHEDULE 13D/A	Shattuck Labs, Inc. STTK	9.90%	9,819,084	view →
2025-04-29	SCHEDULE	Absci Corp ABSI	6.50%	8,335,116	view →
2024-07-19	SC	Augmedix, Inc.	—	—	view →
2023-12-28	SC	FATE THERAPEUTICS INC FATE	—	—	view →
2023-06-21	SC	MedAvail Holdings, Inc.	—	—	view →
2023-06-13	SC	IGM Biosciences, Inc.	—	—	view →
2023-03-15	SC	MedAvail Holdings, Inc.	—	—	view →
2022-10-05	SC	IGM Biosciences, Inc.	—	—	view →
2022-07-06	SC	MedAvail Holdings, Inc.	—	—	view →
2022-01-14	SC	MedAvail Holdings, Inc.	—	—	view →
2021-11-29	SC	MedAvail Holdings, Inc.	—	—	view →
2021-03-01	SC	Augmedix, Inc.	—	—	view →
2021-01-12	SC	FATE THERAPEUTICS INC FATE	—	—	view →
2020-12-15	SC	IGM Biosciences, Inc.	—	—	view →
2020-09-10	SC	IGM Biosciences, Inc.	—	—	view →
2019-10-24	SC	ALDER BIOPHARMACEUTICALS INC	—	—	view →
2019-09-17	SC	FATE THERAPEUTICS INC FATE	—	—	view →

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