Prothena Ownership | Who Owns Prothena?
Prothena Ownership Summary
Prothena is owned by 77.52% institutional investors, 18.66% insiders, and 3.82% retail investors. Fmr is the largest institutional shareholder, holding 15.01% of PRTA shares. Vanguard Health Care Inv is the top mutual fund, with 7.77% of its assets in Prothena shares.
PRTA Ownership Benchmark
| Type | Name | % Inst | % Insiders | % Retail |
|---|---|---|---|---|
| Stock | Prothena | 77.52% | 18.66% | 3.82% |
| Sector | Healthcare Stocks | 488.17% | 11.08% | -399.26% |
| Industry | Biotech Stocks | 306.59% | 11.10% | -217.69% |
Institutional Shareholders
Top Institutional Shareholders by Total Shares
| Holder | Shares | % Holding | Value |
|---|---|---|---|
| Fmr | 8.07M | 15.01% | $111.79M |
| Wellington management group llp | 5.13M | 9.54% | $71.06M |
| Blackrock funding, inc. /de | 3.94M | 7.32% | $23.91M |
| Blackrock | 3.86M | 7.18% | $79.61M |
| Price t rowe associates inc /md/ | 3.69M | 6.85% | $51.05M |
| Adar1 capital management | 3.38M | 6.27% | $20.49M |
| Armistice capital | 2.24M | 4.15% | $13.57M |
| State street | 1.93M | 3.60% | $39.89M |
| Vanguard group | 1.40M | 2.61% | $19.44M |
| Palo alto investors lp | 1.27M | 2.37% | $7.74M |
Top Institutional Shareholders by % of Total Assets
| Holder | Shares | % Assets | Value |
|---|---|---|---|
| Adar1 capital management | 3.38M | 3.14% | $20.49M |
| Birchview capital, lp | 451.02K | 2.72% | $2.74M |
| Palo alto investors lp | 1.27M | 1.65% | $7.74M |
| Boxer capital | 690.00K | 0.75% | $14.24M |
| Dcf advisers | 103.50K | 0.69% | $1.43M |
| Artal group | 1.00M | 0.53% | $20.67M |
| Prosight management, lp | 267.80K | 0.40% | $1.63M |
| Duncan williams asset management | 69.20K | 0.38% | $958.41K |
| Armistice capital | 2.24M | 0.23% | $13.57M |
| Rock springs capital management lp | 492.60K | 0.19% | $2.99M |
Top Buyers
| Holder | Shares | % Assets | Change |
|---|---|---|---|
| Adar1 capital management | 3.38M | 3.14% | 3.38M |
| Acadian asset management | 1.02M | 0.01% | 1.02M |
| Wellington management group llp | 5.13M | 0.01% | 952.09K |
| Balyasny asset management | 575.79K | 0.01% | 575.79K |
| Granahan investment management | 461.08K | 0.11% | 461.08K |
Top Sellers
| Holder | Shares | % Assets | Change |
|---|---|---|---|
| Ecor1 capital | - | - | -11.58M |
| State street | 1.93M | 0.00% | -1.54M |
| Siren | - | - | -1.28M |
| Finepoint capital lp | - | - | -640.07K |
| First light asset management | - | - | -444.95K |
New Positions
| Holder | Shares | % Assets | Change | Value |
|---|---|---|---|---|
| Adar1 capital management | 3.38M | 3.14% | 3.38M | $20.49M |
| Granahan investment management | 461.08K | 0.11% | 461.08K | $2.80M |
| Qube research | 414.83K | 0.00% | 414.83K | $2.52M |
| State of wisconsin investment board | 104.00K | 0.00% | 104.00K | $631.26K |
| Susquehanna portfolio strategies | 71.67K | 0.01% | 71.67K | $435.02K |
Sold Out
| Holder | Change |
|---|---|
| Jfs wealth advisors | -2.00 |
| Cypress capital | -2.00 |
| First manhattan co. llc. | -3.00 |
| Hallmark capital management | -3.00 |
| Register financial advisors | -4.00 |
Institutional Ownership Trends
| Date | Holdings | Change % | Shares | Change % | Ownership | Change % | Increased Position | Change % | Decreased Position | Change % |
|---|---|---|---|---|---|---|---|---|---|---|
| Jun 30, 2025 | 198 | 17.86% | 41,726,109 | -20.15% | 77 | 0.82% | 107 | 81.36% | 41 | -33.87% |
| Mar 31, 2025 | 6 | -96.69% | 2,463,987 | -95.40% | 4 | 0.05% | 2 | -98.06% | 4 | -88.89% |
| Dec 31, 2024 | 107 | -35.93% | 25,474,325 | -49.96% | 47 | 0.53% | 63 | -12.50% | 19 | -57.78% |
| Sep 30, 2024 | 166 | 0.61% | 50,906,096 | 0.22% | 94 | 1.06% | 71 | -18.39% | 45 | 9.76% |
| Jun 30, 2024 | 165 | -4.07% | 50,796,433 | -4.91% | 94 | 0.96% | 87 | 12.99% | 41 | -34.92% |
Top Mutual Funds Shareholders
| Holder | Shares | % Holding | Change |
|---|---|---|---|
| Vanguard Health Care Inv | 4.18M | 7.77% | -39.90K |
| Fidelity Growth Compy Commingled Pl S | 3.38M | 6.28% | 3.55K |
| Fidelity Growth Compy Commingled Pl O | 3.28M | 6.09% | 1.22K |
| Fidelity Growth Company Fund | 2.32M | 4.32% | - |
| T. Rowe Price New Horizons | 1.64M | 3.04% | -251.35K |
| US Small-Cap Growth II Equity Comp | 1.64M | 3.04% | -251.90K |
| iShares Russell 2000 ETF | 927.95K | 1.72% | -17.64K |
| Fidelity Growth Company K6 | 793.58K | 1.47% | -3.55K |
| Federated Hermes MDT SCC Institutional | 784.12K | 1.46% | 404.94K |
| Federated Hermes MDT Small Cap Core IS | 784.12K | 1.46% | 404.94K |
Recent Insider Transactions
| Date | Name | Role | Activity | Value |
|---|---|---|---|---|
| May 06, 2025 | EcoR1 Capital, LLC | - | Sell | $15.16M |
| May 05, 2025 | EcoR1 Capital, LLC | - | Sell | $7.93M |
| May 02, 2025 | EcoR1 Capital, LLC | - | Sell | $27.74M |
| Dec 31, 2024 | SCULLY WILLIAM P | - | Buy | $389.64K |
| Dec 18, 2024 | SCULLY WILLIAM P | - | Buy | $1.02M |
Insider Transactions Trends
| Date | Buy | Sell |
|---|---|---|
| 2025 Q3 | - | - |
| 2025 Q2 | - | 3 |
| 2025 Q1 | 1 | - |
| 2024 Q4 | - | - |
| 2024 Q3 | - | - |
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