Prothena Corp
PRTA
187 hedge funds and large institutions have $465M invested in Prothena Corp in 2026 Q2 according to their latest regulatory filings, with 28 funds opening new positions, 55 increasing their positions, 58 reducing their positions, and 24 closing their positions.
67% more call options, than puts
Call options by funds: $8.79M | Put options by funds: $5.26M
17% more first-time investments, than exits
New positions opened: 28 | Existing positions closed: 24
2.44% more ownership
Funds ownership: 87.83% → 90.27% (+2.4%)
1% more capital invested
Capital invested by funds: $460M → $465M (+$5.45M)
1% more funds holding
Funds holding: 186 → 187 (+1)
5% less repeat investments, than reductions
Existing positions increased: 55 | Existing positions reduced: 58
50% less funds holding in top 10
Funds holding in top 10: 2 → 1 (-1)
Top Buyers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
Acadian Asset Management
Boston,
Massachusetts
|
+$4.57M |
| 2 |
State Street
Boston,
Massachusetts
|
+$4.49M |
| 3 |
Man Group
London,
United Kingdom
|
+$2.93M |
| 4 |
Mackenzie Financial
Toronto Ontario,
Ontario, Canada
|
+$2.37M |
| 5 |
BlackRock
New York
|
+$2.21M |
Top Sellers
| Rank | Fund | Capital Flow |
|---|---|---|
| 1 |
AC
Armistice Capital
New York
|
-$4.27M |
| 2 |
Point72 Asset Management
Stamford,
Connecticut
|
-$3.89M |
| 3 |
Fidelity Investments
Boston,
Massachusetts
|
-$3.48M |
| 4 |
DI
Deeter Investments
Austin,
Texas
|
-$2.92M |
| 5 |
Walleye Capital
New York
|
-$2.69M |
PRTA Hedge Fund Activity: Q2 2026 in Review
187 of the 8,349 institutional investors tracked by Wall St. Rank reported a position in Prothena Corp (PRTA) for Q2 2026, worth a combined $465M — up 1.2% from $460M a quarter earlier.
Buyers outnumbered sellers: 28 funds opened new PRTA positions and 24 closed out — a net gain of 4 holders — while 55 added to existing stakes and 58 trimmed.
The largest buyer was Acadian Asset Management, adding an estimated $4.57M. The largest seller was Armistice Capital, exiting entirely with an estimated $4.27M sold.
- 187 institutional investors held Prothena Corp (PRTA) as of Q2 2026, up from 186 in Q1 2026.
- Funds reported $465M of Prothena Corp stock for Q2 2026, up 1.2% quarter-over-quarter.
- 28 funds opened new Prothena Corp positions in Q2 2026 and 24 closed out, a net change of +4 holders.
- The largest Prothena Corp buyer in Q2 2026 was Acadian Asset Management, an estimated $4.57M added.
- The largest Prothena Corp seller in Q2 2026 was Armistice Capital, an estimated $4.27M sold.
Based on aggregated 13F filings for Q2 2026.