| $350M | ||
| $217M | ||
| $172M | ||
| $109M | ||
| $107M | ||
| $104M |
Buys | $11,231,433 | 17 | 89 |
Sells | $135,975 | 2 | 11 |
| SCULLY WILLIAM P | 10 percent owner | 17 | $11.23M | 0 | $0 | $11.23M |
| Kingston Anne Evans | Chief Strategy Officer | 0 | $0 | 1 | $64,919 | $-64,919 |
| Isaacs Michael John | General Counsel & Company Sec. | 0 | $0 | 1 | $71,055 | $-71,055 |
Prothena Corporation plc, a late-stage clinical biotechnology company, focuses on discovery and development of novel therapies to treat diseases caused by protein dysregulation. Its product pipeline includes Prasinezumab, an investigational humanized monoclonal antibody which is in Phase 3 clinical trial for the treatment of parkinson's disease and other synucleinopathies. The company also develops Coramitug, an investigational antibody, which is in Phase 3 clinical trial for the treatment of transthyretin amyloidosis; BMS-986446, an anti-tau …
Over the last 12 months, insiders at Prothena Corporation plc have bought $11.23M and sold $135,975 worth of Prothena Corporation plc stock.
On average, over the past 5 years, insiders at Prothena Corporation plc have bought $18.69M and sold $26.1M worth of stock each year.
Highest buying activity among insiders over the last 12 months: SCULLY WILLIAM P (10 percent owner) — $11.23M.
The last purchase of 50,000 shares for transaction amount of $403,525 was made by SCULLY WILLIAM P (10 percent owner) on 2026‑10‑23.
| 2026-10-23 | SCULLY WILLIAM P | 10 percent owner | 50,000 0.0944% | $8.07 | $403,525 | +3.29% | ||
| 2026-10-22 | SCULLY WILLIAM P | 10 percent owner | 100,000 0.1903% | $8.19 | $818,520 | +2.24% | ||
| 2026-10-14 | SCULLY WILLIAM P | 10 percent owner | 10,000 0.0193% | $8.46 | $84,569 | +0.78% | ||
| 2026-10-13 | SCULLY WILLIAM P | 10 percent owner | 100,000 0.1909% | $8.35 | $835,480 | +0.48% | ||
| 2026-10-08 | SCULLY WILLIAM P | 10 percent owner | 90,000 0.171% | $8.57 | $770,904 | -2.26% | ||
| 2026-10-07 | SCULLY WILLIAM P | 10 percent owner | 125,000 0.2365% | $8.40 | $1.05M | -0.59% | ||
| 2026-10-02 | SCULLY WILLIAM P | 10 percent owner | 100,000 0.1966% | $8.57 | $857,240 | +0.66% | ||
| 2026-09-29 | SCULLY WILLIAM P | 10 percent owner | 162,000 0.3058% | $8.68 | $1.41M | -4.33% | ||
| 2026-09-28 | SCULLY WILLIAM P | 10 percent owner | 103,500 0.1957% | $8.60 | $889,872 | -3.50% | ||
| 2026-09-02 | SCULLY WILLIAM P | 10 percent owner | 27,000 0.0504% | $9.47 | $255,739 | -12.49% | ||
| 2026-08-20 | SCULLY WILLIAM P | 10 percent owner | 50,000 0.093% | $8.79 | $439,430 | -5.20% | ||
| 2026-08-07 | SCULLY WILLIAM P | 10 percent owner | 37,500 0.0708% | $8.62 | $323,220 | -0.46% | ||
| 2026-07-29 | Sale | Kingston Anne Evans | Chief Strategy Officer | 7,662 0.0145% | $8.47 | $64,919 | +0.99% | |
| 2026-07-29 | Sale | Isaacs Michael John | General Counsel & Company Sec. | 8,386 0.0159% | $8.47 | $71,055 | +0.99% | |
| 2026-06-16 | SCULLY WILLIAM P | 10 percent owner | 20,000 0.0364% | $7.90 | $157,990 | +5.55% | ||
| 2026-06-11 | SCULLY WILLIAM P | 10 percent owner | 125,000 0.2362% | $8.17 | $1.02M | +5.51% | ||
| 2026-06-04 | SCULLY WILLIAM P | 10 percent owner | 50,000 0.0961% | $9.31 | $465,295 | -5.95% | ||
| 2026-06-02 | SCULLY WILLIAM P | 10 percent owner | 50,000 0.098% | $9.43 | $471,300 | -5.22% | ||
| 2026-05-22 | SCULLY WILLIAM P | 10 percent owner | 100,000 0.1907% | $9.81 | $981,300 | -10.99% | ||
| 2025-05-06 | Sale | EcoR1 Capital, LLC | 10 percent owner | 1.98M 3.8331% | $7.64 | $15.16M | +23.40% |
| SCULLY WILLIAM P | 10 percent owner | 1187000 2.3122% | $9.75M | 21 | 0 | <0.0001% |
| EcoR1 Capital, LLC | 10 percent owner | 5304596 10.3329% | $43.55M | 9 | 4 | +87.11% |
| Kinney Gene G. | President and CEO | 12793 0.0249% | $105,030.53 | 1 | 13 | +13.42% |
| Schenk Dale B. | President and CEO | 3333 0.0065% | $27,363.93 | 1 | 2 | +5.51% |
| Nguyen Tran | Chief Strategy Officer and CFO | 3200 0.0062% | $26,272.00 | 2 | 10 | +10.25% |
| Nickerson Tara | Chief Business Officer | 2000 0.0039% | $16,420.00 | 1 | 7 | +5.51% |
| HOMAN ARTHUR W | Chief Legal Officer | 0 0% | $0 | 1 | 9 | +21.36% |
$3,887,391 | 114 | 13.01% | $433.37M | |
$31,123,523 | 108 | 6.46% | $387.86M | |
$24,384,691 | 42 | -30.27% | $396.82M | |
$2,481,409 | 33 | 201.68% | $455.48M | |
$31,271,604 | 28 | 28.69% | $477.19M |
| Increased Positions | 89 | +42.18% | 9M | +21.58% |
| Decreased Positions | 87 | -41.23% | 5M | -11.12% |
| New Positions | 26 | New | 791,783 | New |
| Sold Out Positions | 28 | Sold Out | 1M | Sold Out |
| Total Postitions | 213 | +0.95% | 47M | +10.46% |
| Fmr Llc | $72,691.00 | 14.63% | 7.9M | 0 | 0% | 2025-09-30 |
| Blackrock, Inc. | $33,105.00 | 6.66% | 3.6M | -340,981 | -8.66% | 2025-09-30 |
| Vanguard Group Inc | $18,859.00 | 3.8% | 2.05M | -126,378 | -5.81% | 2025-09-30 |
| Armistice Capital, Llc | $16,781.00 | 3.38% | 1.82M | -412,000 | -18.43% | 2025-09-30 |
| Rubric Capital Management Lp | $14,171.00 | 2.85% | 1.54M | +2M | New | 2025-09-30 |
| Adar1 Capital Management, Llc | $13,516.00 | 2.72% | 1.47M | -2M | -56.47% | 2025-09-30 |
| Palo Alto Investors Lp | $12,181.00 | 2.45% | 1.32M | +49,275 | +3.87% | 2025-09-30 |
| D. E. Shaw & Co., Inc. | $12,102.00 | 2.44% | 1.32M | +923,923 | +236% | 2025-09-30 |
| Acadian Asset Management Llc | $11,401.00 | 2.3% | 1.24M | +221,065 | +21.71% | 2025-09-30 |
| Geode Capital Management, Llc | $9,379.00 | 1.89% | 1.02M | +86,037 | +9.22% | 2025-09-30 |