Latest filingSep 04, 2026Most recent Form 4
ATRA
Atara Biotherapeutics, Inc.
NasdaqHealthcareBiological Products, (No Diagnostic Substances)
Insider activity for last month from 08/05 to 09/05. Counts use processed Form 4 rows. Purchase and sale metrics use codes P and S; totals remain unknown when any matching value is missing. Rows without a usable transaction date cannot be assigned to a rolling period and are excluded.
Total buying$99.9M1 buys
Total selling$4.08M1 sells
Net open-market+$95.9M2 insiders
Open-market mix
Buy vs sell distribution by transaction countInsider activity report
Monthly open-market purchase and sale counts Buys Sells
Transaction codes
By Form 4 transaction code in selected period2transactions
- P · Open-market buys · dominant1 · 50%
- S · Open-market sells1 · 50%
Activity by reported role
A joint filing can contribute to multiple roles2transactions
- Director · dominant1 · 50%
- PRES1 · 50%
Distinct insiders active
Reporting-owner CIKs by month · peak Aug 2026 (1)Aug 2026Sep 2026
Reported Holdings After
Separated by insider, security, and ownership typeNguyen AnhCoCommon Stock · Direct
132,775Aug 17, 2026
Cherry Brian NCommon Stock · Direct
166,486Sep 04, 2026
These are reported post-transaction holdings, not company-wide ownership percentages. Securities, indirect vehicles, and amendments are kept separate.
Filing activity heatmap
Each cell is one day · intensity = transactions · buys green, sells redAug 05 → Sep 05
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Top insiders
By absolute net value across the selected period- NA-$40.9k
Recent filing activity
Most recent 1 transactions · color = transaction code- SSell08/26-$4.08MSEC
Filing detail checks
Secondary metrics for the selected periodFiling-only signals
Deterministic matches in the selected period
ATRA transaction history
Filters apply within this company and selected period by default| Ticker | Insider | Role | Type | Shares | Value | Code | Signals | 90d return | Filed | Trans date |
|---|---|---|---|---|---|---|---|---|---|---|
| ATRA | Nguyen AnhCo | PRES | sale | 5.06k | -$4.08M | S | — | 08/26 | 08/17 |
Atara Biotherapeutics, Inc. Insider Activity FAQ
SEC Form 4 contextWho recently reported transactions at Atara Biotherapeutics, Inc.?
Cherry Brian N, Nguyen AnhCo.
When was the latest reported open-market purchase?
Cherry Brian N reported a buy on Sep 04, 2026 valued at $99.9M. Read the SEC filing.
When was the latest reported open-market sale?
Nguyen AnhCo reported a sale on Aug 17, 2026 valued at $4.08M. Read the SEC filing.
What is the recent purchase and sale balance?
Net open-market buying in the selected period was $959,110.86. This describes filed transactions, not a bullish rating.
Where can I see the original SEC filing?
Every transaction row and latest-activity fact links to its original SEC filing.
What do these Form 4 transaction codes mean?
P and S generally describe open-market or private purchases and sales. A, D, F, M, X, G, J, and V describe awards, issuer dispositions, tax withholding, exercises, gifts, other transactions, and voluntary early reports; review each filing and its footnotes for context.