Atara Biotherapeutics, Inc.: which funds bought and sold
Institutions that bought and sold Atara Biotherapeutics shares in Q2 2026, from the holdings they reported to the SEC on Form 13F for March 31, 2026 and June 30, 2026.
Between March 31, 2026 and June 30, 2026, 16 institutions that filed 13F reports for both quarters added to or opened positions in Atara Biotherapeutics, and 9 cut or closed them. Together they added a net 1.9M shares, +74.2% on what they held at the start of the quarter. Active managers and hedge funds on our list were net buyers of 2.0M shares (+160.5%); index fund managers were net buyers of 57K shares (+13.1%). 4 opened a new position and 1 sold out entirely.
Bought, Q2 2026 16 institutions, 4 of them new holders Sold, Q2 2026 9 institutions, 1 of them sold out
Net change, all compared +1.9M shares (+74.2%)
Net change, active managers +2.0M shares (+160.5%), 4 bought, 3 sold
Buyers versus sellers
16 bought 11 9 sold
Active managers and hedge funds 4 bought · 3 sold · +2.0M
Index fund managers 5 bought · 1 sold · +57K
Other institutions 7 bought · 5 sold · −114K
Biggest buyers
| Institution | Change in shares | Shares June 30, 2026 | Value |
|---|---|---|---|
| Ecor1 Capital, LLC Hedge fund | +1.5M +1458.3% | 1.6M | $17.8M |
| Point72 Asset Management, L.P. Hedge fund | +493K +254.0% | 688K | $7.9M |
| Adage Capital Partners Gp, L.L.C. Hedge fund | +150K +21.4% | 850K | $9.8M |
| Vanguard Capital Management LLC Index funds | +29K +13.4% | 247K | $2.8M |
| Xtx Topco Ltd | +15K New position | 15K | $175,678 |
| Citadel Advisors LLC Hedge fund | +10K New position | 10K | $116,625 |
| Vanguard Fiduciary Trust Co Index funds | +9,415 +28.0% | 43K | $494,053 |
| Geode Capital Management, LLC Index funds | +8,982 +13.6% | 75K | $862,924 |
| Blackrock, Inc. Index funds | +5,433 +6.9% | 84K | $969,544 |
| Northern Trust Corp Index funds | +4,251 +34.4% | 17K | $190,465 |
| Royal Bank Of Canada | +424 +9.8% | 4,743 | $55,000 |
| Caitong International Asset Management Co., Ltd | +311 New position | 311 | $3,570 |
| Barclays PLC | +304 New position | 304 | $3,490 |
| Jones Financial Companies LLLP | +100 +14.2% | 803 | $8,440 |
| Citigroup Inc | +96 +9600.0% | 97 | $1,114 |
| Morgan Stanley | +9 +0.1% | 9,178 | $105,368 |
| Institution | Change in shares | Shares June 30, 2026 | Value |
|---|---|---|---|
| Ecor1 Capital, LLC Hedge fund | +1.5M +1458.3% | 1.6M | $17.8M |
| Point72 Asset Management, L.P. Hedge fund | +493K +254.0% | 688K | $7.9M |
| Adage Capital Partners Gp, L.L.C. Hedge fund | +150K +21.4% | 850K | $9.8M |
| Citadel Advisors LLC Hedge fund | +10K New position | 10K | $116,625 |
Biggest sellers
| Institution | Change in shares | Shares June 30, 2026 | Value |
|---|---|---|---|
| Acadian Asset Management LLC Active manager | −92K −70.3% | 39K | $444,000 |
| Mackenzie Financial Corp | −80K −25.6% | 233K | $2.7M |
| UBS Group AG | −46K −92.1% | 3,979 | $45,679 |
| Millennium Management LLC Hedge fund | −35K −73.4% | 13K | $145,566 |
| Bridgeway Capital Management, LLC Active manager | −19K −57.2% | 14K | $160,720 |
| Jane Street Group, LLC | −3,525 −10.4% | 30K | $348,360 |
| Rhumbline Advisers Index funds | −175 Sold out | 0 | — |
| Sbi Securities Co., Ltd. | −170 −10.8% | 1,404 | $16,118 |
| BNP Paribas Financial Markets | −12 −20.7% | 46 | $528 |
| Institution | Change in shares | Shares June 30, 2026 | Value |
|---|---|---|---|
| Acadian Asset Management LLC Active manager | −92K −70.3% | 39K | $444,000 |
| Millennium Management LLC Hedge fund | −35K −73.4% | 13K | $145,566 |
| Bridgeway Capital Management, LLC Active manager | −19K −57.2% | 14K | $160,720 |
New positions
| Institution | Shares | Value June 30, 2026 |
|---|---|---|
| Xtx Topco Ltd | 15K | $175,678 |
| Citadel Advisors LLCHedge fund | 10K | $116,625 |
| Caitong International Asset Management Co., Ltd | 311 | $3,570 |
| Barclays PLC | 304 | $3,490 |
Sold out
| Institution | Shares | Value March 31, 2026 |
|---|---|---|
| Rhumbline AdvisersIndex funds | 175 | $827 |
Who holds the shares
- Institutions reporting
- 35
- Ten largest holders
- 95.4% of 13F-reported shares
- Index fund managers
- 11.0% of 13F-reported shares
- Active managers and hedge funds
- 71.2% of 13F-reported shares
| Type | Bought | Sold | New | Sold out | Net change in shares | Net % |
|---|---|---|---|---|---|---|
| Active managers and hedge funds | 4 | 3 | 1 | 0 | +2.0M | +160.5% |
| Index fund managers | 5 | 1 | 0 | 1 | +57K | +13.1% |
| Other institutions | 7 | 5 | 3 | 0 | −114K | −12.5% |
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