Atara Biotherapeutics
ATRA
33 hedge funds and large institutions have $12.1M invested in Atara Biotherapeutics in 2026 Q1 according to their latest regulatory filings, with 7 funds opening new positions, 10 increasing their positions, 3 reducing their positions, and 14 closing their positions.
233% more repeat investments, than reductions
Existing positions increased: 10 | Existing positions reduced: 3
2.93% more ownership
Funds ownership: 28.43% → 31.36% (+2.9%)
20% less funds holding
Funds holding: 41 → 33 (-8)
50% less first-time investments, than exits
New positions opened: 7 | Existing positions closed: 14
67% less capital invested
Capital invested by funds: $37.1M → $12.1M (-$24.9M)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Adage Capital Partners
Boston,
Massachusetts
|
+$4.27M |
| 2 |
Mackenzie Financial
Toronto Ontario,
Ontario, Canada
|
+$1.56M |
| 3 |
Point72 Asset Management
Stamford,
Connecticut
|
+$1.07M |
| 4 |
Acadian Asset Management
Boston,
Massachusetts
|
+$469K |
| 5 |
UBS Group
Zurich,
Switzerland
|
+$297K |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
EC
EcoR1 Capital
San Francisco,
California
|
-$2.89M |
| 2 |
Marshall Wace
London,
United Kingdom
|
-$2.69M |
| 3 |
GC
Globeflex Capital
San Diego,
California
|
-$1.4M |
| 4 |
Renaissance Technologies
New York
|
-$543K |
| 5 |
Cambridge Investment Research Advisors
Fairfield,
Iowa
|
-$414K |
ATRA Hedge Fund Activity: Q1 2026 in Review
33 of the 8,206 institutional investors tracked by Wall St. Rank reported a position in Atara Biotherapeutics (ATRA) for Q1 2026, worth a combined $12.1M — down 67% from $37.1M a quarter earlier.
Sellers outnumbered buyers: 14 funds closed out of ATRA and 7 opened new positions — a net loss of 7 holders — while 3 trimmed existing stakes and 10 added.
The largest buyer was Adage Capital Partners, opening a new position worth an estimated $4.27M. The largest seller was EcoR1 Capital, cutting an estimated $2.89M.
- 33 institutional investors held Atara Biotherapeutics (ATRA) as of Q1 2026, down from 41 in Q4 2025.
- Funds reported $12.1M of Atara Biotherapeutics stock for Q1 2026, down 67% quarter-over-quarter.
- 7 funds opened new Atara Biotherapeutics positions in Q1 2026 and 14 closed out, a net change of -7 holders.
- The largest Atara Biotherapeutics buyer in Q1 2026 was Adage Capital Partners, an estimated $4.27M added.
- The largest Atara Biotherapeutics seller in Q1 2026 was EcoR1 Capital, an estimated $2.89M sold.
Based on aggregated 13F filings for Q1 2026.