Quick Takeaways
- ATRA - Atara Biotherapeutics, Inc. has 25 insiders with reported activity on this page.
- Net insider value flow over the last year: +$676,115.
- Recent transaction rows are available for direct filing-level review.
- Info
- Insider Trading
- Financials
- Holders
Insider Transactions Reported by 25 Insiders of Atara Biotherapeutics, Inc.
- Symbol
- ATRA on Nasdaq
- Location
- Thousand Oaks, CA
What Changed
- Buy value: $856,794; sell value: $180,679.
- Net share flow: <span class="text-green-600">+54,255</span>.
Why This Matters
- This page gives a plain-language issuer insider context before you inspect transaction-level evidence.
- Use the filing links below to verify timestamps, codes, and ownership impacts directly from SEC forms.
Official SEC Source
Insider trading overview
Last 12 monthsNet insider flow leans to buying over the last 12 months. Net value: +$676,115.
Buys
$856,794
Shares: 74,335
Insiders: 1
Sells
$180,679
Shares: 20,080
Insiders: 2
Net
+$676,115
Shares: +54,255
Insiders: -1
| Window (months) | Buy shares | Sell shares | Buy $ | Sell $ | Net $ |
|---|---|---|---|---|---|
| 0-3 | 0 | 5,100 | $0 | $25,928 | +$25,928 |
| 3-6 | 0 | 4,719 | $0 | $62,225 | +$62,225 |
| 6-9 | 74,335 | 4,767 | $856,794 | $55,370 | +$912,164 |
| 9-12 | 0 | 5,494 | $0 | $37,156 | +$37,156 |
Atara Biotherapeutics, Inc. executives and other stock owners filed with the SEC include:
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| Adiumentum Capital Fund I LP | Director, Other*, 10%+ Owner | $10,487,308 | Mixed | 16 May 2025 | ||
| Redmile Group, LLC | Director | $3,356,927 | Mixed | 16 May 2025 | ||
| Panacea Innovation Ltd | 10%+ Owner | $3,332,563 | +$856,794 | +35% | Mixed | 17 Mar 2026 |
| AnhCo Nguyen | President and CEO, Director | $636,697 | -$110,191 | -15% | Mixed | 09 Mar 2026 |
| Pascal Touchon | Director | $589,339 | Mixed | 10 Jun 2025 | ||
| Eric J. Hyllengren | Former EVP, CFO & COO | $393,448 | Filing P/S | 31 Mar 2025 | ||
| Carol Giltner Gallagher | Director | $249,570 | Mixed | 10 Jun 2025 | ||
| Yanina Grant-Huerta | Chief Accounting Officer | $231,622 | -$70,489 | -23% | Mixed | 09 Mar 2026 |
| Eric Dobmeier | Director | $219,133 | Mixed | 10 Nov 2023 | ||
| Amar Murugan | EVP, Chief Legal Officer | $177,890 | Filing P/S | 16 Aug 2024 | ||
| William K. Heiden | Director | $167,741 | Mixed | 10 Jun 2025 | ||
| Matthew K. Fust | Director | $137,501 | Mixed | 10 Jun 2025 | ||
| Maria Grazia Roncarolo | Director | $131,302 | Mixed | 10 Jun 2025 | ||
| Jill Henrich | EVP, Chief Regulatory Officer | $130,697 | Filing P/S | 03 Mar 2025 | ||
| Ameet Mallik | Director | $127,975 | Mixed | 10 Jun 2025 | ||
| Jakob Dupont | EVP, Head of R&D | $113,119 | Mixed | 02 Mar 2023 | ||
| Charlene A. Banard | EVP, Chief Technical Officer | $107,368 | Mixed | 16 May 2023 | ||
| Utpal Koppikar | Chief Financial Officer | $70,789 | Mixed | 02 Mar 2023 | ||
| Kristin Yarema | Chief Commercial Officer | $66,680 | Mixed | 01 Mar 2022 | ||
| Manher Joshi | EVP, Chief Medical Officer | $66,629 | Filing P/S | 16 Nov 2023 | ||
| Beth C. Seidenberg | Director | $45,080 | Mixed | 31 May 2023 | ||
| Joe Newell | Chief Operations Officer | $43,995 | Mixed | 16 Nov 2021 | ||
| Roy D. Baynes | Director | $16,922 | Mixed | 23 Jun 2022 | ||
| Ronald C. Renaud Jr. | Director | $12,254 | Mixed | 23 Jun 2022 | ||
| Nachiappan Subramanian | Director | Mixed | 16 May 2025 |
Top shareholders of Atara Biotherapeutics, Inc. (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Ownership % is shown only when it is directly reported or safely comparable across share classes.
Methodology: rows are grouped by holder and ranked by the holder's primary source value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
| Holder | Source | Role / Reporting | Ownership % | Shares | Holdings Value | 12M Net Δ | As of | Details |
|---|---|---|---|---|---|---|---|---|
| Redmile Group, LLC |
13D/G
3/4/5
13F
|
Director · Company |
9.9%
|
751,223
|
$10,764,875 | +$659,400 | 12 Nov 2025 | |
| Adiumentum Capital Fund I LP |
3/4/5
13D/G
|
Director, Other*, 10%+ Owner |
20%
from 13D/G
|
1,586,588
mixed-class rows
|
$10,487,308 | — | 16 May 2025 | |
| EcoR1 Capital, LLC |
13F
13D/G
|
Company |
9.9%
from 13D/G
|
573,183
|
$10,368,880 | — | 31 Dec 2025 | |
| VANGUARD GROUP INC |
13F
|
Company |
3.1%
|
225,940
|
$4,087,255 | — | 31 Dec 2025 | |
| Panacea Innovation Ltd |
3/4/5
13D/G
|
10%+ Owner · Panacea Innovation Limited |
20%
from 13D/G
|
307,894
mixed-class rows
|
$3,332,563 | +$856,794 | 17 Mar 2026 | |
| MARSHALL WACE, LLP |
13F
|
Company |
2.1%
|
148,632
|
$2,688,752 | — | 31 Dec 2025 | |
| GLOBEFLEX CAPITAL L P |
13F
|
Company |
1.1%
|
77,224
|
$1,396,982 | — | 31 Dec 2025 | |
| BlackRock, Inc. |
13F
|
Company |
0.93%
|
67,108
|
$1,213,984 | — | 31 Dec 2025 | |
| GEODE CAPITAL MANAGEMENT, LLC |
13F
|
Company |
0.86%
|
62,381
|
$1,129,112 | — | 31 Dec 2025 | |
| MACKENZIE FINANCIAL CORP |
13F
|
Company |
0.81%
|
58,668
|
$1,046,920 | — | 31 Dec 2025 | |
| ACADIAN ASSET MANAGEMENT LLC |
13F
|
Company |
0.75%
|
54,048
|
$976,000 | — | 31 Dec 2025 | |
| STALEY CAPITAL ADVISERS INC |
13F
|
Company |
0.69%
|
50,000
|
$904,500 | — | 31 Dec 2025 | |
| AnhCo Nguyen |
3/4/5
|
President and CEO, Director |
2%
|
143,078
|
$636,697 | -$110,191 | 09 Mar 2026 | |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC |
13F
|
Company |
0.45%
|
32,691
|
$591,380 | — | 31 Dec 2025 | |
| Pascal Touchon |
3/4/5
|
Director |
1.1%
|
77,955
|
$589,339 | — | 10 Jun 2025 | |
| RENAISSANCE TECHNOLOGIES LLC |
13F
|
Company |
0.42%
|
30,040
|
$543,424 | — | 31 Dec 2025 | |
| STATE STREET CORP |
13F
|
Company |
0.37%
|
26,453
|
$478,535 | — | 31 Dec 2025 | |
| Cambridge Investment Research Advisors, Inc. |
13F
|
Company |
0.32%
|
22,864
|
$414,000 | — | 31 Dec 2025 | |
| Eric J. Hyllengren |
3/4/5
|
Former EVP, CFO & COO |
—
mixed-class rows
|
58,887
mixed-class rows
|
$393,448 | — | 31 Mar 2025 | |
| Quadrature Capital Ltd |
13F
|
Company |
0.28%
|
20,321
|
$367,607 | — | 31 Dec 2025 | |
| Point72 Asset Management, L.P. |
13F
|
Company |
0.25%
|
18,296
|
$330,975 | — | 31 Dec 2025 | |
| FMR LLC |
13F
|
Company |
0.24%
|
17,156
|
$310,352 | — | 31 Dec 2025 | |
| MORGAN STANLEY |
13F
|
Company |
0.22%
|
15,991
|
$289,276 | — | 31 Dec 2025 | |
| CITADEL ADVISORS LLC |
13F
|
Company |
0.22%
|
15,577
|
$281,788 | — | 31 Dec 2025 | |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP |
13F
|
Company |
0.19%
|
14,018
|
$253,586 | — | 31 Dec 2025 | |
| JANE STREET GROUP, LLC |
13F
|
Company |
0.19%
|
13,990
|
$253,080 | — | 31 Dec 2025 | |
| Carol Giltner Gallagher |
3/4/5
|
Director |
0.46%
|
33,012
|
$249,570 | — | 10 Jun 2025 | |
| Yanina Grant-Huerta |
3/4/5
|
Chief Accounting Officer |
0.72%
|
52,050
|
$231,622 | -$70,489 | 09 Mar 2026 | |
| NORTHERN TRUST CORP |
13F
|
Company |
0.17%
|
12,340
|
$223,231 | — | 31 Dec 2025 | |
| Walleye Capital LLC |
13F
|
Company |
0.17%
|
12,169
|
$220,137 | — | 31 Dec 2025 | |
| Eric Dobmeier |
3/4/5
|
Director |
—
mixed-class rows
|
642,825
mixed-class rows
|
$219,133 | — | 10 Nov 2023 | |
| Connor, Clark & Lunn Investment Management Ltd. |
13F
|
Company |
0.14%
|
10,446
|
$188,968 | — | 31 Dec 2025 | |
| BANK OF AMERICA CORP /DE/ |
13F
|
Company |
0.14%
|
10,387
|
$187,901 | — | 31 Dec 2025 | |
| DIMENSIONAL FUND ADVISORS LP |
13F
|
Company |
0.14%
|
10,028
|
$181,406 | — | 31 Dec 2025 | |
| Amar Murugan |
3/4/5
|
EVP, Chief Legal Officer |
—
class O/S missing
|
26,827
|
$177,890 | — | 16 Aug 2024 | |
| William K. Heiden |
3/4/5
|
Director |
0.31%
|
22,188
|
$167,741 | — | 10 Jun 2025 | |
| Matthew K. Fust |
3/4/5
|
Director |
0.25%
|
18,188
|
$137,501 | — | 10 Jun 2025 | |
| Maria Grazia Roncarolo |
3/4/5
|
Director |
0.24%
|
17,368
|
$131,302 | — | 10 Jun 2025 | |
| Jill Henrich |
3/4/5
|
EVP, Chief Regulatory Officer |
—
class O/S missing
|
18,679
|
$130,697 | — | 03 Mar 2025 | |
| Ameet Mallik |
3/4/5
|
Director |
0.23%
|
16,928
|
$127,975 | — | 10 Jun 2025 | |
| Jakob Dupont |
3/4/5
|
EVP, Head of R&D |
—
mixed-class rows
|
608,781
mixed-class rows
|
$113,119 | — | 02 Mar 2023 | |
| Charlene A. Banard |
3/4/5
|
EVP, Chief Technical Officer |
—
class O/S missing
|
276,010
|
$107,368 | — | 16 May 2023 | |
| Utpal Koppikar |
3/4/5
|
Chief Financial Officer |
—
class O/S missing
|
181,978
|
$70,789 | — | 02 Mar 2023 | |
| Kristin Yarema |
3/4/5
|
Chief Commercial Officer |
—
mixed-class rows
|
257,007
mixed-class rows
|
$66,680 | — | 01 Mar 2022 | |
| Manher Joshi |
3/4/5
|
EVP, Chief Medical Officer |
—
class O/S missing
|
171,284
|
$66,629 | — | 16 Nov 2023 | |
| Beth C. Seidenberg |
3/4/5
|
Director |
—
mixed-class rows
|
195,386
mixed-class rows
|
$45,080 | — | 31 May 2023 | |
| Joe Newell |
3/4/5
|
Chief Operations Officer |
—
mixed-class rows
|
123,014
mixed-class rows
|
$43,995 | — | 16 Nov 2021 | |
| Tower Research Capital LLC (TRC) |
13F
|
Company |
0.02%
|
1,737
|
$31,422 | — | 31 Dec 2025 | |
| SBI Securities Co., Ltd. |
13F
|
Company |
0.02%
|
1,404
|
$25,398 | — | 31 Dec 2025 | |
| UBS Group AG |
13F
|
Company |
0.02%
|
1,397
|
$25,271 | — | 31 Dec 2025 |
Recent Insider Transactions by Companies or Individuals for Atara Biotherapeutics, Inc.
Showing up to 300 most recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | Value $ | * Price $ | Shares | Shares Owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Panacea Innovation Ltd | ATRA | Common Stock | Tax liability | -5 | 307,894 | 17 Mar 2026 | See Footnotes | |||
| Panacea Innovation Ltd | ATRA | Common Stock | Options Exercise | 531.8% | 259,163 | 307,899 | 17 Mar 2026 | See Footnotes | ||
| Panacea Innovation Ltd | ATRA | Warrants | Options Exercise | -100% | -259,163 | 0 | 17 Mar 2026 | See Footnotes | ||
| AnhCo Nguyen | ATRA | Common Stock | Award | 130.8% | 81,100 | 143,078 | 09 Mar 2026 | Direct | ||
| Yanina Grant-Huerta | ATRA | Common Stock | Award | 63.9% | 20,300 | 52,050 | 09 Mar 2026 | Direct | ||
| Yanina Grant-Huerta | ATRA | Common Stock | Sale | -6.21% | $10,691 | $5.08 | -2,104 | 31,750 | 02 Mar 2026 | Direct |
| AnhCo Nguyen | ATRA | Common Stock | Sale | -4.61% | $15,237 | $5.09 | -2,996 | 61,978 | 02 Mar 2026 | Direct |
| Panacea Innovation Ltd | ATRA | Common Stock | Sale | -5.73% | -80,554 | 1,324,446 | 12 Jan 2026 | See Footnotes | ||
| Panacea Innovation Ltd | ATRA | Common Stock | Tax liability | -1 | 48,736 | 28 Nov 2025 | See Footnotes | |||
| Panacea Innovation Ltd | ATRA | Common Stock | Options Exercise | 48,737 | 48,737 | 28 Nov 2025 | See Footnotes | |||
| Panacea Innovation Ltd | ATRA | Warrants | Options Exercise | -15.8% | -48,737 | 259,163 | 28 Nov 2025 | See Footnotes | ||
| AnhCo Nguyen | ATRA | Common Stock | Sale | -4.29% | $38,437 | $13.19 | -2,915 | 64,974 | 17 Nov 2025 | Direct |
| Yanina Grant-Huerta | ATRA | Common Stock | Sale | -5.12% | $23,788 | $13.19 | -1,804 | 33,454 | 17 Nov 2025 | Direct |
| AnhCo Nguyen | ATRA | Common Stock | Sale | -4.18% | $34,360 | $11.62 | -2,958 | 67,889 | 18 Aug 2025 | Direct |
| Yanina Grant-Huerta | ATRA | Common Stock | Sale | -4.88% | $21,009 | $11.61 | -1,809 | 35,258 | 18 Aug 2025 | Direct |
| Panacea Innovation Ltd | ATRA | Common Stock | Purchase | 4.07% | $670,422 | $12.19 | 55,000 | 1,405,000 | 15 Aug 2025 | See Footnotes |
| Panacea Innovation Ltd | ATRA | Common Stock | Purchase | 1.45% | $186,372 | $9.64 | 19,335 | 1,350,000 | 17 Jul 2025 | See Footnotes |
| Carol Giltner Gallagher | ATRA | Common Stock | Award | 31.1% | 7,828 | 33,012 | 10 Jun 2025 | Direct | ||
| Matthew K. Fust | ATRA | Common Stock | Award | 75.6% | 7,828 | 18,188 | 10 Jun 2025 | Direct | ||
| Pascal Touchon | ATRA | Common Stock | Award | 11.2% | 7,828 | 77,955 | 10 Jun 2025 | Direct | ||
| Maria Grazia Roncarolo | ATRA | Common Stock | Award | 82% | 7,828 | 17,368 | 10 Jun 2025 | Direct | ||
| Ameet Mallik | ATRA | Common Stock | Award | 86% | 7,828 | 16,928 | 10 Jun 2025 | Direct | ||
| William K. Heiden | ATRA | Common Stock | Award | 54.5% | 7,828 | 22,188 | 10 Jun 2025 | Direct | ||
| Yanina Grant-Huerta | ATRA | Common Stock | Sale | -5.65% | $15,000 | $6.76 | -2,218 | 37,067 | 16 May 2025 | Direct |
| AnhCo Nguyen | ATRA | Common Stock | Sale | -4.42% | $22,156 | $6.76 | -3,276 | 70,847 | 16 May 2025 | Direct |
| Adiumentum Capital Fund I LP | ATRA | Common Stock | Award | 6.67% | 75,572 | 1,209,395 | 16 May 2025 | Direct | ||
| Adiumentum Capital Fund I LP | ATRA | Warrants (right to buy) | Award | 151.1% | 227,000 | 377,193 | 16 May 2025 | Direct |
* An asterisk sign (*) next to the price indicates that the price is likely invalid.