Atara Biotherapeutics
ATRA
36 hedge funds and large institutions have $51.3M invested in Atara Biotherapeutics in 2026 Q2 according to their latest regulatory filings, with 4 funds opening new positions, 12 increasing their positions, 8 reducing their positions, and 1 closing their positions.
323% more capital invested
Capital invested by funds: $12.1M → $51.3M (+$39.2M)
300% more first-time investments, than exits
New positions opened: 4 | Existing positions closed: 1
50% more repeat investments, than reductions
Existing positions increased: 12 | Existing positions reduced: 8
18.23% more ownership
Funds ownership: 31.36% → 49.59% (+18%)
9% more funds holding
Funds holding: 33 → 36 (+3)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
EC
EcoR1 Capital
San Francisco,
California
|
+$11.6M |
| 2 |
Point72 Asset Management
Stamford,
Connecticut
|
+$3.94M |
| 3 |
Adage Capital Partners
Boston,
Massachusetts
|
+$1.2M |
| 4 |
Vanguard Capital Management
Malvern,
Pennsylvania
|
+$233K |
| 5 |
XT
XTX Topco
George Town,
Cayman Islands
|
+$122K |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Acadian Asset Management
Boston,
Massachusetts
|
-$734K |
| 2 |
Mackenzie Financial
Toronto Ontario,
Ontario, Canada
|
-$641K |
| 3 |
UBS Group
Zurich,
Switzerland
|
-$368K |
| 4 |
Millennium Management
New York
|
-$279K |
| 5 |
BCM
Bridgeway Capital Management
Houston,
Texas
|
-$149K |
ATRA Hedge Fund Activity: Q2 2026 in Review
36 of the 8,279 institutional investors tracked by Wall St. Rank reported a position in Atara Biotherapeutics (ATRA) for Q2 2026, worth a combined $51.3M — up 323% from $12.1M a quarter earlier.
Buyers outnumbered sellers: 4 funds opened new ATRA positions and 1 closed out — a net gain of 3 holders — while 12 added to existing stakes and 8 trimmed.
The largest buyer was EcoR1 Capital, adding an estimated $11.6M. The largest seller was Acadian Asset Management, cutting an estimated $734K.
- 36 institutional investors held Atara Biotherapeutics (ATRA) as of Q2 2026, up from 33 in Q1 2026.
- Funds reported $51.3M of Atara Biotherapeutics stock for Q2 2026, up 323% quarter-over-quarter.
- 4 funds opened new Atara Biotherapeutics positions in Q2 2026 and 1 closed out, a net change of +3 holders.
- The largest Atara Biotherapeutics buyer in Q2 2026 was EcoR1 Capital, an estimated $11.6M added.
- The largest Atara Biotherapeutics seller in Q2 2026 was Acadian Asset Management, an estimated $734K sold.
Based on aggregated 13F filings for Q2 2026.