| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| Redmile Group, LLC | 9.9% | 0% | $10,764,875 | +$659,400 | 751,223 | +6.5% | Redmile Group, LLC | 12 Nov 2025 |
| EcoR1 Capital, LLC | 9.9% | $10,258,030 | 715,853 | EcoR1 Capital, LLC | 30 Sep 2025 | |||
| Panacea Innovation Ltd | 9.5% | $4,180,000 | 550,000 | Panacea Venture Healthcare Fund II, L.P. | 30 Jan 2025 |
As of 31 Dec 2025, 40 institutional investors reported holding 2,049,655 shares of Atara Biotherapeutics, Inc. - Common Stock (ATRA). This represents 28% of the company’s total 7,230,838 outstanding shares.
The largest institutional shareholders of Atara Biotherapeutics, Inc. - Common Stock (ATRA) together control 28% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| EcoR1 Capital, LLC | 7.9% | 573,183 | 0% | 0.48% | $10,368,880 |
| Redmile Group, LLC | 6.1% | 441,701 | 0% | 0.59% | $7,990,371 |
| VANGUARD GROUP INC | 3.1% | 225,940 | +11% | 0% | $4,087,255 |
| MARSHALL WACE, LLP | 2.1% | 148,632 | +28% | 0% | $2,688,752 |
| GLOBEFLEX CAPITAL L P | 1.1% | 77,224 | +400% | 0.21% | $1,396,982 |
| BlackRock, Inc. | 0.93% | 67,108 | -3.9% | 0% | $1,213,984 |
| GEODE CAPITAL MANAGEMENT, LLC | 0.86% | 62,381 | +3.1% | 0% | $1,129,112 |
| MACKENZIE FINANCIAL CORP | 0.81% | 58,668 | -8.1% | 0% | $1,046,920 |
| ACADIAN ASSET MANAGEMENT LLC | 0.75% | 54,048 | -4.2% | 0% | $976,000 |
| STALEY CAPITAL ADVISERS INC | 0.69% | 50,000 | 0% | 0.04% | $904,500 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 0.45% | 32,691 | +134% | 0.01% | $591,380 |
| RENAISSANCE TECHNOLOGIES LLC | 0.42% | 30,040 | +59% | 0% | $543,424 |
| STATE STREET CORP | 0.37% | 26,453 | +4.8% | 0% | $478,535 |
| Cambridge Investment Research Advisors, Inc. | 0.32% | 22,864 | +34% | 0% | $414,000 |
| Quadrature Capital Ltd | 0.28% | 20,321 | +23% | 0% | $367,607 |
| Point72 Asset Management, L.P. | 0.25% | 18,296 | 0% | $330,975 | |
| FMR LLC | 0.24% | 17,156 | 0% | 0% | $310,352 |
| MORGAN STANLEY | 0.22% | 15,991 | -56% | 0% | $289,276 |
| CITADEL ADVISORS LLC | 0.22% | 15,577 | 0% | $281,788 | |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 0.19% | 14,018 | 0% | $253,586 | |
| JANE STREET GROUP, LLC | 0.19% | 13,990 | -37% | 0% | $253,080 |
| NORTHERN TRUST CORP | 0.17% | 12,340 | +12% | 0% | $223,231 |
| Walleye Capital LLC | 0.17% | 12,169 | 0% | $220,137 | |
| Connor, Clark & Lunn Investment Management Ltd. | 0.14% | 10,446 | 0% | $188,968 | |
| BANK OF AMERICA CORP /DE/ | 0.14% | 10,387 | +78% | 0% | $187,901 |
| Period | Reported Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2025 Q4 | 2,049,655 | $37,062,796 | +$3,113,209 | $18.09 | 40 |
| 2025 Q3 | 1,883,136 | $26,983,314 | +$1,944,887 | $14.33 | 36 |
| 2025 Q2 | 1,803,350 | $13,921,685 | -$1,938,164 | $7.72 | 32 |
| 2025 Q1 | 2,086,793 | $12,393,904 | -$4,023,428 | $5.94 | 36 |
| 2024 Q4 | 2,368,286 | $31,519,295 | -$410,987 | $13.31 | 41 |
| 2024 Q3 | 2,414,500 | $19,628,975 | -$1,762,796 | $8.13 | 33 |
| 2024 Q2 | 2,653,675 | $22,554,322 | +$22,225,788 | $8.50 | 43 |