PRTA
Prothena Corporation plc
NASDAQ: PRTA · HEALTHCARE · BIOTECHNOLOGY
$9.10
+3.29% today
Updated 2026-10-28
Market cap
$420.96M
P/E ratio
—
P/S ratio
7.72x
EPS (TTM)
$-0.82
Dividend yield
—
52W range
$8 – $12
Volume
0.5M
Prothena Corporation plc (PRTA) Insider transactions
Net insider activity
Net selling (2,882,991 shares)
Buy transactions
64
Sell transactions
28
All transactions
| Date | Insider | Title | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 2026-10-14 | SCULLY, WILLIAM P | 10% Owner | P | 10,000 | $8.46 | $84569.00 |
| 2026-10-13 | SCULLY, WILLIAM P | 10% Owner | P | 100,000 | $8.35 | $835480.00 |
| 2026-10-08 | SCULLY, WILLIAM P | 10% Owner | P | 90,000 | $8.57 | $770904.00 |
| 2026-10-07 | SCULLY, WILLIAM P | 10% Owner | P | 125,000 | $8.40 | $1.05M |
| 2026-10-02 | SCULLY, WILLIAM P | 10% Owner | P | 100,000 | $8.57 | $857240.00 |
| 2026-09-29 | SCULLY, WILLIAM P | 10% Owner | P | 162,000 | $8.68 | $1.41M |
| 2026-09-28 | SCULLY, WILLIAM P | 10% Owner | P | 103,500 | $8.60 | $889872.30 |
| 2026-09-18 | SCULLY, WILLIAM P | 10% Owner | P | 100,000 | $8.43 | $843460.00 |
| 2026-09-02 | SCULLY, WILLIAM P | 10% Owner | Buy | 27,000 | $9.47 | $255738.60 |
| 2026-08-20 | SCULLY, WILLIAM P | 10% Owner | Buy | 50,000 | $8.79 | $439430.00 |
| 2026-08-18 | SCULLY, WILLIAM P | 10% Owner | Sale | 627,553 | — | — |
| 2026-08-17 | SCULLY, WILLIAM P | 10% Owner | Buy | 336,000 | — | — |
| 2026-08-10 | SCULLY, WILLIAM P | 10% Owner | Buy | 251,553 | — | — |
| 2026-08-07 | SCULLY, WILLIAM P | 10% Owner | Buy | 34,000 | $8.62 | $293052.80 |
| 2026-08-07 | SCULLY, WILLIAM P | 10% Owner | Buy | 3,500 | $8.62 | $30167.20 |
| 2026-07-29 | KINGSTON, ANNE EVANS | Chief Strategy Officer | Sale | 7,662 | $8.47 | $64919.36 |
| 2026-07-29 | ISAACS, MICHAEL JOHN | General Counsel & Company Sec. | Sale | 8,386 | $8.47 | $71055.42 |
| 2026-07-28 | ZAGO, WAGNER M. | Chief Scientific Officer | Sale | 51,000 | — | — |
| 2026-07-28 | ZAGO, WAGNER M. | Chief Scientific Officer | Sale | 51,000 | $8.56 | $436560.00 |
| 2026-07-28 | WALKER, KARIN L | Chief Accounting Officer | Sale | 15,000 | — | — |
| 2026-07-28 | WALKER, KARIN L | Chief Accounting Officer | Sale | 15,000 | $8.56 | $128400.00 |
| 2026-07-28 | SWANSON, CHAD J. | Chief Development Officer | Sale | 51,000 | — | — |
| 2026-07-28 | SWANSON, CHAD J. | Chief Development Officer | Buy | 51,000 | — | — |
| 2026-07-28 | SWANSON, CHAD J. | Chief Development Officer | Sale | 40,800 | $8.56 | $349248.00 |
| 2026-07-28 | SWANSON, CHAD J. | Chief Development Officer | Sale | 3,467 | $8.56 | $29677.52 |
| 2026-07-28 | SMITH, BRANDON S. | Chief Operating Officer | Sale | 78,000 | — | — |
| 2026-07-28 | SMITH, BRANDON S. | Chief Operating Officer | Sale | 78,000 | $8.56 | $667680.00 |
| 2026-07-28 | NGUYEN, TRAN | Chief Strategy Officer and CFO | Sale | 57,000 | — | — |
| 2026-07-28 | NGUYEN, TRAN | Chief Strategy Officer and CFO | Sale | 57,000 | $8.56 | $487920.00 |
| 2026-07-28 | KINNEY, GENE G. | Director, President and CEO | Sale | 84,000 | — | — |
| 2026-07-28 | KINNEY, GENE G. | Director, President and CEO | Sale | 84,000 | $8.56 | $719040.00 |
| 2026-07-28 | KINGSTON, ANNE EVANS | Chief Strategy Officer | Sale | 3,498 | $8.56 | $29942.88 |
| 2026-07-28 | ISAACS, MICHAEL JOHN | General Counsel & Company Sec. | Sale | 4,694 | $8.56 | $40180.64 |
| 2026-06-16 | SCULLY, WILLIAM P | 10% Owner | Buy | 20,000 | $7.90 | $157990.00 |
| 2026-06-15 | SCULLY, WILLIAM P | 10% Owner | Sale | 325,000 | — | — |
| 2026-06-11 | SCULLY, WILLIAM P | 10% Owner | Buy | 125,000 | $8.17 | $1.02M |
| 2026-06-04 | SCULLY, WILLIAM P | 10% Owner | Buy | 50,000 | $9.31 | $465295.00 |
| 2026-06-02 | SCULLY, WILLIAM P | 10% Owner | Buy | 50,000 | $9.43 | $471300.00 |
| 2026-05-22 | SCULLY, WILLIAM P | 10% Owner | Buy | 100,000 | $9.81 | $981300.00 |
| 2026-05-15 | WELCH, DANIEL G | Director | Buy | 27,000 | — | — |
| 2026-05-15 | SELKOE, DENNIS J. | Director | Buy | 27,000 | — | — |
| 2026-05-15 | EKMAN, LARS | Director | Buy | 27,000 | — | — |
| 2026-05-15 | DUNN, WILLIAM H. JR. | Director | Buy | 27,000 | — | — |
| 2026-05-15 | COOKE, SHANE | Director | Buy | 27,000 | — | — |
| 2026-05-15 | COLLIER, RICHARD T | Director | Buy | 27,000 | — | — |
| 2026-04-10 | KINGSTON, ANNE EVANS | Chief Strategy Officer | Buy | 100,000 | — | — |
| 2026-03-03 | ZAGO, WAGNER M. | Chief Scientific Officer | Buy | 190,000 | — | — |
| 2026-03-03 | WALKER, KARIN L | Chief Accounting Officer | Buy | 150,000 | — | — |
| 2026-03-03 | SWANSON, CHAD J. | Chief Development Officer | Buy | 190,000 | — | — |
| 2026-03-03 | SMITH, BRANDON S. | Chief Operating Officer | Buy | 190,000 | — | — |
| 2026-03-03 | NGUYEN, TRAN | Chief Strategy Officer and CFO | Buy | 230,000 | — | — |
| 2026-03-03 | MALECEK, MICHAEL J | Chief Legal Officer | Buy | 190,000 | — | — |
| 2026-03-03 | KINNEY, GENE G. | Director, President and CEO | Buy | 520,000 | — | — |
| 2025-07-28 | ZAGO, WAGNER M. | Chief Scientific Officer | Buy | 85,000 | — | — |
| 2025-07-28 | WALKER, KARIN L | Chief Accounting Officer | Buy | 25,000 | — | — |
| 2025-07-28 | SWANSON, CHAD J. | Chief Development Officer | Buy | 85,000 | — | — |
| 2025-07-28 | SMITH, BRANDON S. | Chief Operating Officer | Buy | 130,000 | — | — |
| 2025-07-28 | NGUYEN, TRAN | Chief Strategy Officer and CFO | Buy | 95,000 | — | — |
| 2025-07-28 | MALECEK, MICHAEL J | Chief Legal Officer | Buy | 80,000 | — | — |
| 2025-07-28 | KINNEY, GENE G. | Director, President and CEO | Buy | 140,000 | — | — |
| 2025-05-14 | WELCH, DANIEL G | Director | Buy | 20,183 | — | — |
| 2025-05-14 | SELKOE, DENNIS J. | Director | Buy | 20,183 | — | — |
| 2025-05-14 | KIM, HELEN SUSAN | Director | Buy | 20,183 | — | — |
| 2025-05-14 | EKMAN, LARS | Director | Buy | 20,183 | — | — |
| 2025-05-14 | DUNN, WILLIAM H. JR. | Director | Buy | 20,183 | — | — |
| 2025-05-14 | COOKE, SHANE | Director | Buy | 20,183 | — | — |
| 2025-05-14 | COLLIER, RICHARD T | Director | Buy | 20,183 | — | — |
| 2025-05-14 | COBB, PAULA K | Director | Buy | 20,183 | — | — |
| 2025-05-06 | ECOR1, CAPITAL, LLC | 10% Owner | Sale | 1,984,053 | $7.64 | $15.16M |
| 2025-05-05 | ECOR1, CAPITAL, LLC | 10% Owner | Sale | 977,693 | $8.11 | $7.93M |
| 2025-05-02 | ECOR1, CAPITAL, LLC | 10% Owner | Sale | 3,317,938 | $8.36 | $27.74M |
| 2025-03-05 | ZAGO, WAGNER M. | Chief Scientific Officer | Buy | 107,500 | — | — |
| 2025-03-05 | WALKER, KARIN L | Chief Accounting Officer | Buy | 70,000 | — | — |
| 2025-03-05 | SWANSON, CHAD J. | Chief Development Officer | Buy | 107,500 | — | — |
| 2025-03-05 | SMITH, BRANDON S. | Chief Operating Officer | Buy | 107,500 | — | — |
| 2025-03-05 | NGUYEN, TRAN | Chief Strategy Officer and CFO | Buy | 107,500 | — | — |
| 2025-03-05 | MALECEK, MICHAEL J | Chief Legal Officer | Buy | 107,500 | — | — |
| 2025-03-05 | KINNEY, GENE G. | Director, President and CEO | Buy | 375,000 | — | — |
| 2025-03-05 | KARP, CAROL D. | Chief Regulatory Officer | Buy | 107,500 | — | — |
| 2025-03-05 | FORD, DAVID A | Chief People Officer | Buy | 107,500 | — | — |
| 2025-01-15 | SCULLY, WILLIAM P | 10% Owner | Sale | 12,000 | — | — |
| 2025-01-14 | SCULLY, WILLIAM P | 10% Owner | Buy | 100,000 | $12.79 | $1.28M |
| 2025-01-03 | SCULLY, WILLIAM P | 10% Owner | Sale | 1,000 | — | — |
| 2025-01-02 | SCULLY, WILLIAM P | 10% Owner | Sale | 13,200 | — | — |
| 2024-12-31 | SCULLY, WILLIAM P | 10% Owner | Buy | 30,000 | $12.99 | $389640.00 |
| 2024-12-31 | SCULLY, WILLIAM P | 10% Owner | Buy | 1,200 | $13.37 | $16038.24 |
| 2024-12-31 | SCULLY, WILLIAM P | 10% Owner | Buy | 800 | $13.39 | $10715.20 |
| 2024-12-20 | SCULLY, WILLIAM P | 10% Owner | Sale | 40,000 | — | — |
| 2024-12-20 | SCULLY, WILLIAM P | 10% Owner | Buy | 2,000 | $15.91 | $31813.00 |
| 2024-12-20 | SCULLY, WILLIAM P | 10% Owner | Sale | 500 | — | — |
| 2024-12-19 | SCULLY, WILLIAM P | 10% Owner | Sale | 681,000 | — | — |
| 2024-12-18 | SCULLY, WILLIAM P | 10% Owner | Buy | 430,000 | — | — |
| 2024-12-18 | SCULLY, WILLIAM P | 10% Owner | Buy | 73,436 | $13.93 | $1.02M |
| 2024-10-01 | SWANSON, CHAD J. | Chief Development Officer | Buy | 40,000 | — | — |
| 2024-05-15 | WELCH, DANIEL G | Director | Buy | 15,000 | — | — |
| 2024-05-15 | SELKOE, DENNIS J. | Director | Buy | 15,000 | — | — |
| 2024-05-15 | KIM, HELEN SUSAN | Director | Buy | 15,000 | — | — |
| 2024-05-15 | EKMAN, LARS | Director | Buy | 15,000 | — | — |
| 2024-05-15 | DUNN, WILLIAM H. JR. | Director | Buy | 15,000 | — | — |
| 2024-05-15 | COOKE, SHANE | Director | Buy | 15,000 | — | — |
Frequently asked questions
Are PRTA insiders buying or selling?
Over the transactions on record, PRTA insiders have been net buyers, with about $53.86M in stock sold across 28 sales, against 15 open-market purchases.
Does insider selling at PRTA mean the stock will fall?
Not by itself. Most executive selling is pre-scheduled through 10b5-1 plans filed months in advance, and insiders sell for diversification, taxes, and liquidity far more often than out of any view on the price. Insider buying is the stronger signal, especially when several insiders buy around the same time, because there is usually only one reason to put personal cash into the stock.
Which PRTA insiders are selling the most?
Recent selling is concentrated in a few names. ECOR1, CAPITAL, LLC accounts for the largest share on record, with about $50.84M sold. Selling by one or two individuals matters less than broad selling across the whole leadership team, which is the pattern worth watching.