Atara Biotherapeutics, Inc. (ATRA) shareholders
ATRANasdaqBiological Products, (No Diagnostic Substances)Fiscal year ends December 31
$7.70−0.23 (-2.90%)
Close on Nov 13, 2026Market cap $77.29MP/E –Yield –
Ownership
Institutional holdings as of Jun 30, 2026, from 13F filings
Held by institutions
44.5%
4M of 10M shares
Institutional holders
36
4 new, 1 sold out
Net institutional buying
2M
In Q2 2026
Insider trades, 12 months
2 buys · 18 sales
Net bought $1.89M
Shares held by institutions
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Panacea Innovation Limited Joint filing with James Huang (20.00%), Panacea Venture Healthcare Fund II, L.P. (20.00%) and 1 more | 1,712,900 | 20.00% | 13D (active) amendment | Aug 15, 2025 |
| EcoR1 Capital, LLC Joint filing with Oleg Nodelman (17.40%), EcoR1 Capital Fund Qualified, L.P. (16.20%) | 1,552,000 | 17.40% | 13G (passive) amendment | May 7, 2026 |
| Adiumentum Capital Fund I GP LLC Joint filing with Adiumentum Capital Fund I LP (19.99%), Gregory A. Ciongoli (19.99%) | 1,370,081 | 19.99% | 13D (active) amendment | May 14, 2025 |
| James Huang Joint filing with Panacea Innovation Limited (16.10%), Panacea Venture Healthcare Fund II, L.P. (12.40%) and 1 more | 1,318,894 | 16.10% | 13D (active) amendment | May 7, 2026 |
| Green Jeremy Joint filing with Redmile Group, LLC (9.90%), Redmile Biopharma Investments II, L.P. (6.60%) | 950,994 | 9.90% | 13D (active) amendment | Jul 22, 2026 |
| Jeremy C. Green Joint filing with Redmile Group, LLC (9.90%), Redmile Biopharma Investments II, L.P. (6.90%) and 1 more | 950,994 | 9.90% | 13D (active) amendment | May 12, 2026 |
| Adage Capital Management, L.P. Joint filing with Robert Atchinson (8.56%), Phillip Gross (8.56%) | 700,000 | 8.56% | 13G (passive) | Mar 31, 2026 |
| Steven A. Cohen Joint filing with Point72 Asset Management, L.P. (7.60%), Point72 Capital Advisors, Inc. (7.60%) | 687,718 | 7.60% | 13G (passive) amendment | Jun 30, 2026 |
| Panacea Venture Healthcare Fund II, L.P. Joint filing with Panacea Venture Healthcare Fund II GP Company, Ltd. (9.50%), Panacea Innovation Limited (9.50%) and 1 more | 550,000 | 9.50% | 13G (passive) | Jan 30, 2025 |
Top institutional holders
13F holdings as of Jun 30, 2026
| Holder | Shares | % of ATRA | Value | Change | % of portfolio |
|---|---|---|---|---|---|
| EcoR1 Capital, LLC | 1,552,000 | 15.46% | $17.82M | +1,452,407 | 0.87% |
| Adage Capital Partners Gp, L.L.C. | 850,000 | 8.47% | $9.76M | +150,000 | 0.01% |
| Point72 Asset Management, L.P. | 687,718 | 6.85% | $7.90M | +493,454 | 0.01% |
| Redmile Group, LLC | 441,701 | 4.40% | $5.07M | – | 0.34% |
| Vanguard Capital Management LLC | 247,047 | 2.46% | $2.84M | +29,185 | 0.00% |
| Mackenzie Financial Corp | 233,249 | 2.32% | $2.68M | −80,371 | 0.00% |
| BlackRock, Inc. | 84,455 | 0.84% | $969.54K | +5,433 | 0.00% |
| Geode Capital Management, LLC | 75,128 | 0.75% | $862.92K | +8,982 | 0.00% |
| Staley Capital Advisers Inc | 50,000 | 0.50% | $574.00K | – | 0.02% |
| Vanguard Fiduciary Trust Co | 43,036 | 0.43% | $494.05K | +9,415 | 0.00% |
| Acadian Asset Management LLC | 38,845 | 0.39% | $444.00K | −92,065 | 0.00% |
| Jane Street Group, LLC | 30,345 | 0.30% | $348.36K | −3,525 | 0.00% |
| State Street Corp | 26,453 | 0.26% | $303.68K | – | 0.00% |
| Northern Trust Corp | 16,591 | 0.17% | $190.47K | +4,251 | 0.00% |
| FMR LLC | 16,238 | 0.16% | $186.41K | – | 0.00% |
| XTX Topco Ltd | 15,303 | 0.15% | $175.68K | New | 0.00% |
| Bridgeway Capital Management, LLC | 14,000 | 0.14% | $160.72K | −18,691 | 0.00% |
| Millennium Management LLC | 12,680 | 0.13% | $145.57K | −35,009 | 0.00% |
| Citadel Advisors LLC | 10,159 | 0.10% | $116.63K | New | 0.00% |
| Morgan Stanley | 9,178 | 0.09% | $105.37K | +9 | 0.00% |
Institutional buying and selling by quarter
Positions opened, added to, reduced and closed by 13F filers
| Quarter | Holders | Shares held | % of shares | New / added | Reduced / closed | Shares bought | Shares sold |
|---|---|---|---|---|---|---|---|
| Q2 2026 | 36 | 4M | 44.5% | 4 / 12 | 8 / 1 | 2M | 0M |
| Q1 2026 | 33 | 3M | 25.5% | 7 / 10 | 3 / 14 | 2M | 1M |
| Q4 2025 | 41 | 2M | 20.4% | 7 / 12 | 9 / 3 | 0M | 0M |
| Q3 2025 | 37 | 2M | 18.8% | 9 / 9 | 7 / 4 | 0M | 0M |
| Q2 2025 | 32 | 2M | 18.0% | 4 / 5 | 6 / 9 | 0M | 0M |
| Q1 2025 | 37 | 2M | 20.8% | 5 / 8 | 14 / 11 | 0M | 0M |
| Q4 2024 | 43 | 2M | 23.8% | 11 / 13 | 11 / 3 | 0M | 0M |
| Q3 2024 | 35 | 2M | 24.1% | 4 / 13 | 11 / 16 | 0M | 1M |
| Q2 2024 | 48 | 3M | 28.3% | 13 / 11 | 21 / 47 | 1M | 1M |
| Q1 2024 | 82 | 3M | 34.8% | 16 / 28 | 27 / 25 | 1M | 1M |
| Q4 2023 | 91 | 3M | 27.4% | 18 / 30 | 32 / 35 | 1M | 2M |
| Q3 2023 | 109 | 4M | 35.2% | 11 / 41 | 39 / 20 | 0M | 0M |
Top mutual fund and ETF holders
Latest monthly portfolio reports (Form N-PORT)
18 funds held ATRA in Q2 2026, 74% of their shares through ETFs. Each fund counts once per quarter, from its quarter-end report.
| Fund | Shares | % of ATRA | Value | % of fund | As of |
|---|---|---|---|---|---|
| Vanguard Total Stock Market Index Fund | 158,646 | 1.58% | $1.82M | 0.00% | Jun 30, 2026 |
| Vanguard Extended Market Index Fund | 82,758 | 0.82% | $950.06K | 0.00% | Jun 30, 2026 |
| Fidelity Extended Market Index Fund | 29,408 | 0.29% | $309.08K | 0.00% | May 31, 2026 |
| iShares Micro-Cap ETF | 17,227 | 0.17% | $197.77K | 0.01% | Jun 30, 2026 |
| VIP Disciplined Small Cap Portfolio | 16,238 | 0.16% | $186.41K | 0.03% | Jun 30, 2026 |
| Ultra-Small Company Market Fund | 14,000 | 0.14% | $160.72K | 0.11% | Jun 30, 2026 |
| Fidelity Total Market Index Fund | 10,479 | 0.10% | $110.13K | 0.00% | May 31, 2026 |
| Fidelity Series Total Market Index Fund | 8,665 | 0.09% | $91.07K | 0.00% | May 31, 2026 |
| Fidelity Nasdaq Composite Index Fund | 4,612 | 0.05% | $48.47K | 0.00% | May 31, 2026 |
| Vanguard Institutional Total Stock Market Index Fund | 2,844 | 0.03% | $32.65K | 0.00% | Jun 30, 2026 |
| Vanguard Balanced Index Fund | 2,799 | 0.03% | $32.13K | 0.00% | Jun 30, 2026 |
| Schwab Total Stock Market Index Fund | 1,643 | 0.02% | $13.77K | 0.00% | Jul 31, 2026 |
| 1290 VT Micro Cap Portfolio | 1,147 | 0.01% | $13.17K | 0.01% | Jun 30, 2026 |
| Total Stock Market Index Trust | 210 | 0.00% | $2.41K | 0.00% | Jun 30, 2026 |
| Dimensional U.S. Small Cap ETF | 135 | 0.00% | $1.13K | 0.00% | Jul 31, 2026 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| AnhCo Nguyen | President and CEO, Director | 132,775 | 1.32% | Aug 26, 2026 |
| Kevin G. Sarney | Interim CFO | – | – | Jul 6, 2026 |
| Yanina Grant-Huerta | Chief Accounting Officer | 49,636 | 0.49% | May 20, 2026 |
| Jill Henrich | EVP, Chief Regulatory Officer | 18,679 | 0.19% | Mar 5, 2025 |
| Brian N. Cherry | Director | 166,486 | 1.66% | Sep 4, 2026 |
| Redmile Group, LLC | Director | 636,912 | 6.35% | Jul 24, 2026 |
| Jeremy Green | Director | 441,701 | 4.40% | Jul 24, 2026 |
| Matthew K. Fust | Director | 30,188 | 0.30% | Jun 11, 2026 |
| William K. Heiden | Director | 34,188 | 0.34% | Jun 11, 2026 |
| Gregory Austin Ciongoli | Director, 10% owner | 1,221,395 | 12.17% | Jun 11, 2026 |
| James Huang | Director, 10% owner | 1,324,446 | 13.19% | May 11, 2026 |
| Carol Giltner Gallagher | Director | 95,668 | 0.95% | Jun 12, 2025 |
| Ameet Mallik | Director | 16,928 | 0.17% | Jun 12, 2025 |
| Pascal Touchon | Director | 77,955 | 0.78% | Jun 12, 2025 |
| Maria Grazia Roncarolo | Director | 17,368 | 0.17% | Jun 12, 2025 |
| Nachiappan Subramanian | Director | – | – | May 23, 2025 |
| Capital Fund I. GP LLC Adiumentum | Director, 10% owner | 1,209,395 | 12.05% | May 16, 2025 |
| Capital Fund I. LP Adiumentum | Director, 10% owner | – | – | May 16, 2025 |
| Innovation Ltd Panacea | 10% owner | 1,318,894 | 13.14% | May 11, 2026 |
| EcoR1 Capital, LLC | 10% owner | 1,552,000 | 15.46% | May 11, 2026 |
| Eric J. Hyllengren | – | 56,231 | 0.56% | Apr 2, 2025 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| Brian N. Cherry Director | Sep 4, 2026 | Buy | +104,166 | $9.60 | $999.99K | 166,486 |
| AnhCo Nguyen President and CEO, Director | Aug 17, 2026 | Sale | −5,062 | $8.08 | $40.90K | 132,775 |
| Redmile Group, LLC Director | Jul 22, 2026 | Option exercise | +195,211 | – | – | 636,912 |
| Redmile Group, LLC Director | Jul 22, 2026 | Tax withholding | −60 | – | – | 636,852 |
| Brian N. Cherry Director | Jun 11, 2026 | Award | +24,000 | – | – | 62,320 |
| William K. Heiden Director | Jun 9, 2026 | Award | +12,000 | – | – | 34,188 |
| Matthew K. Fust Director | Jun 9, 2026 | Award | +12,000 | – | – | 30,188 |
| Gregory Austin Ciongoli Director, 10% owner | Jun 9, 2026 | Award | +12,000 | – | – | 12,000 |
| Yanina Grant-Huerta Chief Accounting Officer | May 18, 2026 | Sale | −2,414 | $9.13 | $22.04K | 49,636 |
| AnhCo Nguyen President and CEO, Director | May 18, 2026 | Sale | −5,241 | $9.13 | $47.85K | 137,837 |
| EcoR1 Capital, LLC 10% owner | May 7, 2026 | Buy | +507,407 | $9.35 | $4.74M | 1,552,000 |
| Innovation Ltd Panacea 10% owner | May 7, 2026 | Sale | −313,446 | $10.10 | $3.17M | 1,011,000 |
| Innovation Ltd Panacea 10% owner | Mar 17, 2026 | Tax withholding | −5 | $5.23 | $26 | 307,894 |
| Innovation Ltd Panacea 10% owner | Mar 17, 2026 | Option exercise | +259,163 | – | – | 307,899 |
| Yanina Grant-Huerta Chief Accounting Officer | Mar 9, 2026 | Award | +20,300 | – | – | 52,050 |
| AnhCo Nguyen President and CEO, Director | Mar 9, 2026 | Award | +81,100 | – | – | 143,078 |
| AnhCo Nguyen President and CEO, Director | Mar 2, 2026 | Sale | −1,442 | $5.09 | $7.34K | 61,978 |
| AnhCo Nguyen President and CEO, Director | Mar 2, 2026 | Sale | −198 | $5.08 | $1.01K | 64,776 |
| AnhCo Nguyen President and CEO, Director | Mar 2, 2026 | Sale | −1,298 | $5.09 | $6.61K | 63,420 |
| AnhCo Nguyen President and CEO, Director | Mar 2, 2026 | Sale | −58 | $5.08 | $295 | 64,718 |
| Yanina Grant-Huerta Chief Accounting Officer | Mar 2, 2026 | Sale | −100 | $5.08 | $508 | 31,750 |
| Yanina Grant-Huerta Chief Accounting Officer | Mar 2, 2026 | Sale | −24 | $5.08 | $122 | 33,830 |
| Yanina Grant-Huerta Chief Accounting Officer | Mar 2, 2026 | Sale | −1,603 | $5.08 | $8.14K | 32,227 |
| Yanina Grant-Huerta Chief Accounting Officer | Mar 2, 2026 | Sale | −377 | $5.08 | $1.92K | 31,850 |
| James Huang Director, 10% owner | Jan 12, 2026 | Sale | −80,554 | $6.07 | $488.96K | 1,324,446 |
| Innovation Ltd Panacea 10% owner | Nov 28, 2025 | Option exercise | +48,737 | – | – | 48,737 |
| Innovation Ltd Panacea 10% owner | Nov 28, 2025 | Tax withholding | −1 | $14.03 | $14 | 48,736 |
| AnhCo Nguyen President and CEO, Director | Nov 17, 2025 | Sale | −2,859 | $13.19 | $37.71K | 65,030 |
| AnhCo Nguyen President and CEO, Director | Nov 17, 2025 | Sale | −56 | $13.19 | $739 | 64,974 |
| Yanina Grant-Huerta Chief Accounting Officer | Nov 17, 2025 | Sale | −85 | $13.19 | $1.12K | 33,528 |
| Yanina Grant-Huerta Chief Accounting Officer | Nov 17, 2025 | Sale | −74 | $13.19 | $976 | 33,454 |
| Yanina Grant-Huerta Chief Accounting Officer | Nov 17, 2025 | Sale | −1,645 | $13.19 | $21.70K | 33,613 |
| Yanina Grant-Huerta Chief Accounting Officer | Aug 18, 2025 | Sale | −1,668 | $11.61 | $19.37K | 35,258 |
| Yanina Grant-Huerta Chief Accounting Officer | Aug 18, 2025 | Sale | −86 | $11.61 | $998 | 36,926 |
| Yanina Grant-Huerta Chief Accounting Officer | Aug 18, 2025 | Sale | −55 | $11.61 | $639 | 37,012 |
| AnhCo Nguyen President and CEO, Director | Aug 18, 2025 | Sale | −1,281 | $11.62 | $14.89K | 69,509 |
| AnhCo Nguyen President and CEO, Director | Aug 18, 2025 | Sale | −1,620 | $11.62 | $18.82K | 67,889 |
| AnhCo Nguyen President and CEO, Director | Aug 18, 2025 | Sale | −57 | $11.61 | $662 | 70,790 |
| Innovation Ltd Panacea 10% owner | Aug 15, 2025 | Buy | +55,000 | $12.19 | $670.45K | 1,405,000 |
| James Huang Director, 10% owner | Jul 17, 2025 | Buy | +19,335 | $9.64 | $186.39K | 1,350,000 |
| Carol Giltner Gallagher Director | Jun 10, 2025 | Award | +7,828 | – | – | 33,012 |
| Matthew K. Fust Director | Jun 10, 2025 | Award | +7,828 | – | – | 18,188 |
| William K. Heiden Director | Jun 10, 2025 | Award | +7,828 | – | – | 22,188 |
| Pascal Touchon Director | Jun 10, 2025 | Award | +7,828 | – | – | 77,955 |
| Maria Grazia Roncarolo Director | Jun 10, 2025 | Award | +7,828 | – | – | 17,368 |
| Ameet Mallik Director | Jun 10, 2025 | Award | +7,828 | – | – | 16,928 |
| Yanina Grant-Huerta Chief Accounting Officer | May 16, 2025 | Sale | −2,218 | $6.76 | $14.99K | 37,067 |
| AnhCo Nguyen President and CEO, Director | May 16, 2025 | Sale | −3,276 | $6.76 | $22.15K | 70,847 |
| Capital Fund I. GP LLC Adiumentum Director, 10% owner | May 16, 2025 | Award | +75,572 | $6.61 | $499.53K | 1,209,395 |
| AnhCo Nguyen President and CEO, Director | Mar 3, 2025 | Sale | −3,331 | $7.00 | $23.32K | 74,123 |
| Eric J. Hyllengren EVP, CFO and COO | Mar 3, 2025 | Sale | −1,211 | $7.00 | $8.48K | 56,231 |
| Jill Henrich EVP, Chief Regulatory Officer | Mar 3, 2025 | Sale | −1,059 | $7.00 | $7.41K | 18,679 |
| Eric J. Hyllengren EVP, CFO and COO | Jan 27, 2025 | Award | +34,050 | – | – | 57,442 |
| AnhCo Nguyen President and CEO, Director | Nov 18, 2024 | Sale | −1,664 | $11.20 | $18.64K | 77,454 |
| Eric J. Hyllengren EVP, CFO and COO | Nov 18, 2024 | Sale | −1,364 | $11.20 | $15.28K | 23,392 |
| Jill Henrich EVP, Chief Regulatory Officer | Nov 18, 2024 | Sale | −1,000 | $11.20 | $11.20K | 19,378 |
| AnhCo Nguyen President and CEO, Director | Sep 9, 2024 | Award | +45,000 | – | – | 79,118 |
| Eric J. Hyllengren EVP, CFO | Aug 16, 2024 | Sale | −1,041 | $6.63 | $6.90K | 24,785 |
| Eric J. Hyllengren EVP, CFO | Aug 16, 2024 | Sale | −29 | $6.63 | $192 | 24,756 |
| AnhCo Nguyen EVP, Chief Sci. & Tech Officer | Aug 16, 2024 | Sale | −56 | $6.63 | $371 | 34,118 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Short interest
Shares sold short and not yet bought back, as of Oct 30, 2026 (FINRA, reported twice a month)
Short % of float
6.63%
0M shares short
Days to cover
13.4
At 0M shares a day
Change since last report
-15.3%
From 0M shares
Short volume, 20 days
42.2%
Of volume reported to FINRA
Shares sold short, last 12 months
Short sale volume counts trades marked short on any given day, including market-maker hedging, so it runs far higher than the share of Atara Biotherapeutics's stock actually held short. Settlement fails (shares not delivered on time) peaked at 3,906 shares on Sep 28, 2026 over the last 90 days.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| AnhCo Nguyen Director, Officer | Aug 26, 2026 | 5,062 | $42.32K | Aug 17, 2026 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| AnhCo Nguyen Director, Officer | May 18, 2026 | 5,981 | $62.68K | May 18, 2026 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Yanina Grant-Huerta Officer | May 18, 2026 | 2,754 | $28.86K | May 18, 2026 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Innovation Ltd Panacea 10% Stockholder | May 7, 2026 | 313,446 | $3.17M | May 7, 2026 | The Common Stock was purchased in multiple open market transactions from January 2025 through August 2025 as well as a registered direct financing in May 2025. |
| Yanina Grant-Huerta Officer | Mar 2, 2026 | 2,355 | $12.76K | Mar 2, 2026 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| AnhCo Nguyen Director, Officer | Mar 2, 2026 | 3,355 | $18.18K | Mar 2, 2026 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Innovation Ltd Panacea 10% Stockholder | Jan 12, 2026 | 80,554 | $473.66K | Jan 12, 2026 | The Common Stock was purchased in multiple open market transactions from January 2025 through August 2025 as well as a registered direct financing in May 2025. |
| Yanina Grant-Huerta Officer | Nov 17, 2025 | 2,069 | $28.47K | Nov 17, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| AnhCo Nguyen Director, Officer | Nov 17, 2025 | 3,346 | $46.04K | Nov 17, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| AnhCo Nguyen Director, Officer | Aug 18, 2025 | 3,346 | $41.12K | Aug 18, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Yanina Grant-Huerta Officer | Aug 18, 2025 | 2,048 | $25.17K | Aug 18, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Yanina Grant-Huerta Officer | May 16, 2025 | 2,350 | $17.88K | May 16, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| AnhCo Nguyen Director, Officer | May 16, 2025 | 3,471 | $26.41K | May 16, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Eric J. Hyllengren Officer | Mar 3, 2025 | 1,426 | $9.85K | Mar 3, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
| Jill Henrich Officer | Mar 3, 2025 | 1,245 | $8.60K | Mar 3, 2025 | Settlement of vested RSUs issued under an S-8 Registration Plan |
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