Form4insider filings, from the source

Company · CIK 0001604464 · SIC 2836 — Biological Products, (No Diagnostic Substances) · Nasdaq

Atara Biotherapeutics, Inc. · ATRA

Insider activity reported against this company. All insider holders · On EDGAR ↗

1M3M6M1Y2YAll datashares as filed — not split-adjusted
Open-market buys & salesbuys $1.0M · 1sales $41k · 1net $959k
$10k$10k$100k$100k$1M$1MbuyssalesSep 2025Nov 2025Jan 2026Mar 2026May 2026Jul 2026Sep 2026

Reported at this company — common stock

TradeReported (ET)InsiderSharesAvg priceTotalOwned afterΔ stakeFlags
Sep 4, 2026 PForm 4 →Sep 4, 6:20 pm EDTBrian N CherryDirector104,166$9.60$999,994166,486+167%
Aug 17, 2026 SForm 4 →Aug 26, 7:45 pm EDTAnhCo NguyenPresident and CEO, Director5,062$8.08$40,883132,775−3.67% late
Jul 22, 2026 FMForm 4 →Jul 24, 9:00 pm EDTRedmile Group, LLC +1Director195,271——636,852—
Jun 11, 2026 AForm 4 →Jun 15, 6:51 pm EDTBrian N CherryDirector24,000——62,320—
Jun 9, 2026 AForm 4 →Jun 11, 4:37 pm EDTWilliam K HeidenDirector12,000——34,188—
Jun 9, 2026 AForm 4 →Jun 11, 4:36 pm EDTMatthew K FustDirector12,000——30,188—
Jun 9, 2026 AForm 4 →Jun 11, 4:36 pm EDTGregory Austin CiongoliDirector, 10% Owner12,000——12,000—

Reported at this company — derivatives (options, RSUs, warrants)

TradeReported (ET)InsiderSharesAvg priceTotalOwned afterΔ stakeFlags
Jul 22, 2026 MForm 4 →Jul 24, 9:00 pm EDTRedmile Group, LLC +1Director195,211——0—