Prothena Corp Public's three largest insider shareholders as of September 29, 2026 are Capital, Llc Ecor1 (TenPercentOwner, 11.58Mn shares), Capital, Llc Ecor1 (TenPercentOwner, 11.58Mn shares), Capital, Llc Ecor1 (TenPercentOwner, 5.30Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Capital, Llc Ecor1 | TenPercentOwner | 0 | 5,304,596 | 5,304,596 | 79.7% | 06 May, 2025 |
| 2 | William P Scully | TenPercentOwner | 927,000 | 0 | 927,000 | 13.9% | 21 Sep, 2026 |
| 3 | Michael J Malecek | Chief Legal Officer | 80,000 | 0 | 80,000 | 1.2% | 30 Jul, 2025 |
| 4 | Gene G. Kinney | President And Ceo | 68,793 | 0 | 68,793 | 1.0% | 30 Jul, 2026 |
| 5 | Anne Evans Kingston | Chief Strategy Officer | 55,782 | 0 | 55,782 | 0.8% | 30 Jul, 2026 |
| 6 | Brandon S. Smith | Chief Operating Officer | 52,000 | 0 | 52,000 | 0.8% | 30 Jul, 2026 |
| 7 | Chad J. Swanson | Chief Development Officer | 40,733 | 0 | 40,733 | 0.6% | 30 Jul, 2026 |
| 8 | Tran Nguyen | Chief Strategy Officer And Cfo | 40,205 | 0 | 40,205 | 0.6% | 30 Jul, 2026 |
| 9 | Michael John Isaacs | General Counsel Company Sec. | 35,745 | 0 | 35,745 | 0.5% | 30 Jul, 2026 |
| 10 | Wagner M. Zago | Chief Scientific Officer | 34,000 | 0 | 34,000 | 0.5% | 30 Jul, 2026 |
| 11 | Karin L Walker | Chief Accounting Officer | 10,000 | 0 | 10,000 | 0.2% | 30 Jul, 2026 |
| 12 | Dennis J. Selkoe | Director | 2,845 | 0 | 2,845 | 0.0% | 03 Jul, 2023 |
| 13 | Richard T Collier | Director | 1,219 | 0 | 1,219 | 0.0% | 05 Jan, 2023 |
| 14 | Lars Ekman | Director, Other | 243 | 0 | 243 | 0.0% | 05 Jan, 2023 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 18 Sep, 2026 | William P Scully | TenPercentOwner | Acquired P | 100,000 | $8.43 | $843.46K | 927,000 | Direct |
| 02 Sep, 2026 | William P Scully | TenPercentOwner | Acquired P | 27,000 | $9.47 | $255.74K | 827,000 | Direct |
| 20 Aug, 2026 | William P Scully | TenPercentOwner | Acquired P | 50,000 | $8.79 | $439.43K | 800,000 | Direct |
| 17 Aug, 2026 | William P Scully | TenPercentOwner | Acquired G | 336,000 | $0.00 | $0 | 1,377,553 | Direct |
| 18 Aug, 2026 | William P Scully | TenPercentOwner | Disposed G | 627,553 | $0.00 | $0 | 750,000 | Direct |
| 10 Aug, 2026 | William P Scully | TenPercentOwner | Acquired G | 251,553 | $0.00 | $0 | 1,041,553 | Direct |
| 07 Aug, 2026 | William P Scully | TenPercentOwner | Acquired P | 34,000 | $8.62 | $293.05K | 790,000 | Direct |
| 07 Aug, 2026 | William P Scully | TenPercentOwner | Acquired P | 3,500 | $8.62 | $30.17K | 83,500 | Indirect |
| 28 Jul, 2026 | Gene G. Kinney | President And Ceo | Acquired M | 84,000 | — | — | 152,793 | Direct |
| 28 Jul, 2026 | Tran Nguyen | Chief Strategy Officer And Cfo | Acquired M | 57,000 | — | — | 97,205 | Direct |
| 28 Jul, 2026 | Anne Evans Kingston | Chief Strategy Officer | Disposed F | 3,498 | $8.56 | $29.94K | 63,444 | Direct |
| 28 Jul, 2026 | Michael John Isaacs | General Counsel Company Sec. | Disposed F | 4,694 | $8.56 | $40.18K | 44,131 | Direct |
| 28 Jul, 2026 | Wagner M. Zago | Chief Scientific Officer | Acquired M | 51,000 | — | — | 85,000 | Direct |
| 28 Jul, 2026 | Chad J. Swanson | Chief Development Officer | Acquired M | 51,000 | — | — | 85,000 | Direct |
| 28 Jul, 2026 | Karin L Walker | Chief Accounting Officer | Acquired M | 15,000 | — | — | 25,000 | Direct |
| 28 Jul, 2026 | Brandon S. Smith | Chief Operating Officer | Acquired M | 78,000 | — | — | 130,000 | Direct |
| 28 Jul, 2026 | Chad J. Swanson | Chief Development Officer | Disposed D | 40,800 | $8.56 | $349.25K | 44,200 | Direct |
| 28 Jul, 2026 | Wagner M. Zago | Chief Scientific Officer | Disposed D | 51,000 | $8.56 | $436.56K | 34,000 | Direct |
| 28 Jul, 2026 | Gene G. Kinney | President And Ceo | Disposed D | 84,000 | $8.56 | $719.04K | 68,793 | Direct |
| 28 Jul, 2026 | Karin L Walker | Chief Accounting Officer | Disposed D | 15,000 | $8.56 | $128.40K | 10,000 | Direct |