PRTA insider buying – Prothena Corp Public Ltd Co
20 insider purchases since 2016 worth $86.5M by 3 different insiders. Last 12 months: 12 purchases, $8.4M. Most recent filing: 2026-11-10.
Mid company Public float $327M (latest 10-K, SEC).
Same time range as the chart above - each mark sits under the week of the trade. Circles = purchases (height = price paid, size = amount), red triangles = open-market sales of $50k+. Prices as reported, not adjusted for later stock splits. 5 older purchases (before the 5-year window) are listed in the table below.
Purchases are open-market buys (SEC Form 4, code "P") - insiders paying with their own money. Sales are open-market sales (code "S") of $50,000 or more; many sales are pre-planned (Rule 10b5-1) or made for taxes and diversification. Each row links to the original filing.
Bought, sold, still holding?
| Insider | Bought | First / last buy | Sold since 2016 | Holds now* | Status |
|---|---|---|---|---|---|
| EcoR1 Capital, LLC 10% Owner | $75.2M 6× · 2,970,376 sh | 2021-02-12 2022-05-05 | 2× · $81.7M last 2025-05-02 | 5,304,596 shares as of 2025-05-06 | Sold part |
| SCULLY WILLIAM P 10% Owner | $11.2M 13× · 1,172,436 sh | 2024-12-18 2026-11-09 | – | 1,328,000 shares as of 2026-09-30 | Holds - never sold |
| Nguyen Tran CFO | $51,320 1× · 1,000 sh | 2017-03-09 2017-03-09 | 10× · $13.3M last 2023-05-17 | 40,205 shares as of 2026-07-30 | Sold part |
* Shares held after the insider's most recent SEC filing for this company (all share classes, direct and indirect). If an insider stops filing, later changes are not known.
Insider buying and selling by year
| Year | Purchases | Bought | Buyers | Sales | Sold |
|---|---|---|---|---|---|
| 2026 | 12 | $8.4M | 1 | 2 | $135,926 |
| 2025 | 1 | $2.8M | 1 | 1 | $50.8M |
| 2024 | 0 | – | – | 1 | $170,000 |
| 2023 | 0 | – | – | 48 | $28.5M |
| 2022 | 2 | $42.1M | 1 | 38 | $56.4M |
| 2021 | 4 | $33.1M | 1 | 15 | $13.9M |
| 2017 | 1 | $51,320 | 1 | 18 | $7.1M |
| 2016 | 0 | – | – | 14 | $5.1M |
Insider purchases
| Filed | Insider | Role | Shares | Avg price | Value | Holdings | Filing |
|---|---|---|---|---|---|---|---|
| 2026-11-10 | SCULLY WILLIAM P | 10% Owner | 140,000 | $8.53 | $1.2M | +17% | SEC |
| 2026-09-30 | SCULLY WILLIAM P | 10% Owner | 162,000 | $8.68 | $1.4M | +311.5% | SEC |
| 2026-09-29 | SCULLY WILLIAM P | 10% Owner | 103,500 | $8.60 | $890,100 | +124.0% | SEC |
| 2026-09-21 | SCULLY WILLIAM P | 10% Owner | 100,000 | $8.43 | $843,000 | +12.1% | SEC |
| 2026-09-03 | SCULLY WILLIAM P | 10% Owner | 27,000 | $9.47 | $255,690 | +3.4% | SEC |
| 2026-08-21 | SCULLY WILLIAM P | 10% Owner | 50,000 | $8.79 | $439,500 | +6.7% | SEC |
| 2026-08-10 | SCULLY WILLIAM P | 10% Owner | 37,500 | $8.62 | $323,250 | +5.0% | SEC |
| 2026-06-18 | SCULLY WILLIAM P | 10% Owner | 20,000 | $7.90 | $158,000 | +2.7% | SEC |
| 2026-06-12 | SCULLY WILLIAM P | 10% Owner | 125,000 | $8.17 | $1.0M | +13.4% | SEC |
| 2026-06-05 | SCULLY WILLIAM P | 10% Owner | 50,000 | $9.31 | $465,500 | +5.6% | SEC |
| 2026-06-03 | SCULLY WILLIAM P | 10% Owner | 50,000 | $9.43 | $471,500 | +6.0% | SEC |
| 2026-05-26 | SCULLY WILLIAM P | 10% Owner | 100,000 | $9.81 | $981,000 | +13.6% | SEC |
| 2025-05-02 | SCULLY WILLIAM P | 10% Owner | 207,436 | $13.26 | $2.8M | +19.0% | SEC |
| 2022-05-09 | EcoR1 Capital, LLC | 10% Owner | 1,062,736 | $29.02 | $30.8M | +10.1% | SEC |
| 2022-01-12 | EcoR1 Capital, LLC | 10% Owner | 300,000 | $37.50 | $11.2M | +2.7% | SEC |
| 2021-03-25 | EcoR1 Capital, LLC | 10% Owner | 875,000 | $20.75 | $18.2M | +8.6% | SEC |
| 2021-02-25 | EcoR1 Capital, LLC | 10% Owner | 55,200 | $21.24 | $1.2M | +0.5% | SEC |
| 2021-02-22 | EcoR1 Capital, LLC | 10% Owner | 44,100 | $3.68 | $162,288 | +0.4% | SEC |
| 2021-02-17 | EcoR1 Capital, LLC | 10% Owner | 633,340 | $21.56 | $13.7M | +6.7% | SEC |
| 2017-03-09 | Nguyen Tran | CFO | 1,000 | $51.32 | $51,320 | +45.5% | SEC |
Insider sales
| Filed | Insider | Role | Shares | Avg price | Value | Type | Filing |
|---|---|---|---|---|---|---|---|
| 2026-07-30 | Kingston Anne Evans | Officer | 7,662 | $8.47 | $64,897 | Sale | SEC |
| 2026-07-30 | Isaacs Michael John | Officer | 8,386 | $8.47 | $71,029 | Sale | SEC |
| 2025-05-06 | EcoR1 Capital, LLC | 10% Owner | 6,279,684 | $8.09 | $50.8M | Sale | SEC |
| 2024-01-24 | Walker Karin L | Officer | 5,000 | $34.00 | $170,000 | Sale | SEC |
| 2023-12-20 | Walker Karin L | Officer | 5,000 | $37.19 | $185,958 | Sale | SEC |
| 2023-11-30 | Walker Karin L | Officer | 5,000 | $34.00 | $170,000 | Sale | SEC |
| 2023-10-25 | Walker Karin L | Officer | 5,000 | $41.04 | $205,179 | Sale | SEC |
| 2023-10-11 | Smith Brandon S. | Officer | 4,000 | $46.74 | $186,977 | Sale | SEC |
| 2023-10-04 | Karp Carol D. | Officer | 5,000 | $46.61 | $233,067 | Sale | SEC |
| 2023-09-27 | Malecek Michael J | Officer | 5,000 | $47.37 | $236,862 | Sale | SEC |
| 2023-09-19 | Walker Karin L | Officer | 5,000 | $52.36 | $261,800 | Sale | SEC |
| 2023-09-13 | Smith Brandon S. | Officer | 4,000 | $55.49 | $221,975 | Sale | SEC |
| 2023-09-13 | Garren Hideki | Officer | 2,000 | $55.48 | $110,960 | Sale | SEC |
| 2023-09-06 | Karp Carol D. | Officer | 5,000 | $54.76 | $273,803 | Sale | SEC |
| 2023-08-30 | Malecek Michael J | Officer | 5,000 | $55.02 | $275,081 | Sale | SEC |
Showing the latest 15 of 137 sales of $50,000+ since 2016.
Compiled automatically from public SEC filings. Not investment advice. Get every new insider purchase in the daily report.
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