PRTANasdaqPharmaceutical PreparationsFiscal year ends December 31
PROTHENA CORP PUBLIC LTD CO
Financials through Q2 FY2026, quarter ended Jun 30, 2026Last filing: 10-Q on Aug 6, 2026
$8.48+0.13 (+1.56%)
Close on Oct 19, 2026
- Market cap
- $442.19M
- P/E (TTM)
- –
- Dividend yield
- –
Ownership
Who owns Prothena Corp Public's shares
Held by institutions
–
Shares held, 13F filers
Institutional holders
–
Net institutional buying
–
Insider trades, 12 months
12 buys · 2 sales
Net bought $7.12M
Holders of more than 5%
Latest Schedule 13D (active) or 13G (passive) filed by each holder
| Holder | Shares | % of class | Filing | As of |
|---|---|---|---|---|
| Abigail P. Johnson | 7,199,218 | 13.80% | 13G (passive) amendment | Jun 30, 2026 |
| Scully William P | 5,378,846 | 10.30% | 13G (passive) amendment | May 7, 2026 |
| Fennell Todd W. | 5,248,846 | 10.20% | 13G (passive) amendment | Aug 18, 2026 |
| Rubric Capital Management LP | 5,000,000 | 9.29% | 13G (passive) amendment | Mar 31, 2026 |
| BlackRock, Inc. | 3,587,480 | 6.90% | 13G (passive) amendment | Jun 30, 2026 |
| Logos Global Management GP LLC | 2,950,000 | 5.50% | 13G (passive) | May 29, 2025 |
| EcoR1 Capital, LLC | 11,584,280 | 21.50% | 13D (active) amendment | Dec 31, 2024 |
Officers, directors and major owners
People who filed Forms 3, 4 or 5 in the last two years
| Name | Role | Shares owned | % of shares | Latest filing |
|---|---|---|---|---|
| Gene G. Kinney | President and CEO, Director | 68,793 | 0.13% | Jul 30, 2026 |
| Karin L. Walker | Chief Accounting Officer | 25,000 | 0.05% | Jul 30, 2026 |
| Brandon S. Smith | Chief Operating Officer | 52,000 | 0.10% | Jul 30, 2026 |
| Michael John Isaacs | General Counsel & Company Sec. | 35,745 | 0.07% | Jul 30, 2026 |
| Chad J. Swanson | Chief Development Officer | 44,200 | 0.09% | Jul 30, 2026 |
| Anne Evans Kingston | Chief Strategy Officer | 55,782 | 0.11% | Jul 30, 2026 |
| Tran Nguyen | Chief Strategy Officer and CFO | 40,205 | 0.08% | Jul 30, 2026 |
| Wagner M. Zago | Chief Scientific Officer | 85,000 | 0.17% | Jul 30, 2026 |
| Michael J. Malecek | Chief Legal Officer | 80,000 | 0.16% | Mar 5, 2026 |
| David A. Ford | Chief People Officer | – | – | Mar 7, 2025 |
| Carol D. Karp | Chief Regulatory Officer | 5,000 | 0.01% | Mar 7, 2025 |
| Shane Cooke | Director | 5,000 | 0.01% | May 15, 2026 |
| Lars Ekman | Director | 3,148 | 0.01% | May 15, 2026 |
| Richard T. Collier | Director | 6,219 | 0.01% | May 15, 2026 |
| Dennis J. Selkoe | Director | 4,208 | 0.01% | May 15, 2026 |
| Daniel G. Welch | Director | – | – | May 15, 2026 |
| William H. Dunn Jr. | Director | – | – | May 15, 2026 |
| Paula K. Cobb | Director | – | – | May 16, 2025 |
| Helen Susan Kim | Director | – | – | May 16, 2025 |
| William P. Scully | 10% owner | 1,328,000 | 2.59% | Sep 30, 2026 |
| Todd W. Fennell | 10% owner | – | – | Aug 18, 2026 |
| EcoR1 Capital, LLC | 10% owner | 5,304,596 | 10.33% | May 6, 2025 |
Insider trades
Common stock transactions reported on Form 4, newest first
| Insider | Date | Transaction | Shares | Price | Value | Shares after |
|---|---|---|---|---|---|---|
| William P. Scully 10% owner | Sep 29, 2026 | Buy | +162,000 | $8.68 | $1.41M | 214,000 |
| William P. Scully 10% owner | Sep 28, 2026 | Buy | +103,500 | $8.60 | $890.10K | 187,000 |
| William P. Scully 10% owner | Sep 18, 2026 | Buy | +100,000 | $8.43 | $843.00K | 927,000 |
| William P. Scully 10% owner | Sep 2, 2026 | Buy | +27,000 | $9.47 | $255.69K | 827,000 |
| William P. Scully 10% owner | Aug 20, 2026 | Buy | +50,000 | $8.79 | $439.50K | 800,000 |
| William P. Scully 10% owner | Aug 18, 2026 | Gift | −627,553 | – | – | 750,000 |
| William P. Scully 10% owner | Aug 17, 2026 | Gift | +336,000 | – | – | 1,377,553 |
| William P. Scully 10% owner | Aug 10, 2026 | Gift | +251,553 | – | – | 1,041,553 |
| William P. Scully 10% owner | Aug 7, 2026 | Buy | +34,000 | $8.62 | $293.08K | 790,000 |
| William P. Scully 10% owner | Aug 7, 2026 | Buy | +3,500 | $8.62 | $30.17K | 83,500 |
| Anne Evans Kingston Chief Strategy Officer | Jul 29, 2026 | Sale(10b5-1 plan) | −7,662 | $8.47 | $64.90K | 55,782 |
| Michael John Isaacs General Counsel & Company Sec. | Jul 29, 2026 | Sale(10b5-1 plan) | −8,386 | $8.47 | $71.03K | 35,745 |
| Wagner M. Zago Chief Scientific Officer | Jul 28, 2026 | Option exercise | +51,000 | – | – | 85,000 |
| Wagner M. Zago Chief Scientific Officer | Jul 28, 2026 | Returned to company | −51,000 | $8.56 | $436.56K | 34,000 |
| Gene G. Kinney President and CEO, Director | Jul 28, 2026 | Returned to company | −84,000 | $8.56 | $719.04K | 68,793 |
| Gene G. Kinney President and CEO, Director | Jul 28, 2026 | Option exercise | +84,000 | – | – | 152,793 |
| Anne Evans Kingston Chief Strategy Officer | Jul 28, 2026 | Tax withholding | −3,498 | $8.56 | $29.94K | 63,444 |
| Chad J. Swanson Chief Development Officer | Jul 28, 2026 | Returned to company | −40,800 | $8.56 | $349.25K | 44,200 |
| Chad J. Swanson Chief Development Officer | Jul 28, 2026 | Tax withholding | −3,467 | $8.56 | $29.68K | 40,733 |
| Chad J. Swanson Chief Development Officer | Jul 28, 2026 | Option exercise | +51,000 | – | – | 85,000 |
| Michael John Isaacs General Counsel & Company Sec. | Jul 28, 2026 | Tax withholding | −4,694 | $8.56 | $40.18K | 44,131 |
| Brandon S. Smith Chief Operating Officer | Jul 28, 2026 | Returned to company | −78,000 | $8.56 | $667.68K | 52,000 |
| Brandon S. Smith Chief Operating Officer | Jul 28, 2026 | Option exercise | +78,000 | – | – | 130,000 |
| Karin L. Walker Chief Accounting Officer | Jul 28, 2026 | Option exercise | +15,000 | – | – | 25,000 |
| Karin L. Walker Chief Accounting Officer | Jul 28, 2026 | Returned to company | −15,000 | $8.56 | $128.40K | 10,000 |
| Tran Nguyen Chief Strategy Officer and CFO | Jul 28, 2026 | Returned to company | −57,000 | $8.56 | $487.92K | 40,205 |
| Tran Nguyen Chief Strategy Officer and CFO | Jul 28, 2026 | Option exercise | +57,000 | – | – | 97,205 |
| William P. Scully 10% owner | Jun 16, 2026 | Buy | +20,000 | $7.90 | $158.00K | 756,000 |
| William P. Scully 10% owner | Jun 15, 2026 | Gift | −325,000 | – | – | 736,000 |
| William P. Scully 10% owner | Jun 11, 2026 | Buy | +125,000 | $8.17 | $1.02M | 1,061,000 |
| William P. Scully 10% owner | Jun 4, 2026 | Buy | +50,000 | $9.31 | $465.50K | 936,000 |
| William P. Scully 10% owner | Jun 2, 2026 | Buy | +50,000 | $9.43 | $471.50K | 886,000 |
| William P. Scully 10% owner | May 22, 2026 | Buy | +100,000 | $9.81 | $981.00K | 836,000 |
| Brandon S. Smith Chief Operating Officer | Jul 28, 2025 | Award | +130,000 | – | – | 130,000 |
| Karin L. Walker Chief Accounting Officer | Jul 28, 2025 | Award | +25,000 | – | – | 25,000 |
| Gene G. Kinney President and CEO, Director | Jul 28, 2025 | Award | +140,000 | – | – | 152,793 |
| Wagner M. Zago Chief Scientific Officer | Jul 28, 2025 | Award | +85,000 | – | – | 85,000 |
| Tran Nguyen Chief Strategy Officer and CFO | Jul 28, 2025 | Award | +95,000 | – | – | 97,205 |
| Michael J. Malecek Chief Legal Officer | Jul 28, 2025 | Award | +80,000 | – | – | 80,000 |
| Chad J. Swanson Chief Development Officer | Jul 28, 2025 | Award | +85,000 | – | – | 85,000 |
| EcoR1 Capital, LLC 10% owner | May 6, 2025 | Sale | −1,984,053 | $7.64 | $15.16M | 5,304,596 |
| EcoR1 Capital, LLC 10% owner | May 5, 2025 | Sale | −977,693 | $8.11 | $7.93M | 7,288,649 |
| EcoR1 Capital, LLC 10% owner | May 2, 2025 | Sale | −3,317,938 | $8.36 | $27.74M | 8,266,342 |
| William P. Scully 10% owner | Jan 15, 2025 | Gift | −12,000 | – | – | 47,000 |
| William P. Scully 10% owner | Jan 14, 2025 | Buy | +100,000 | $12.79 | $1.28M | 735,993 |
| William P. Scully 10% owner | Jan 3, 2025 | Gift | −1,000 | – | – | 635,993 |
| William P. Scully 10% owner | Jan 2, 2025 | Gift | −13,200 | – | – | 636,993 |
| William P. Scully 10% owner | Dec 31, 2024 | Buy | +1,200 | $13.37 | $16.04K | 619,393 |
| William P. Scully 10% owner | Dec 31, 2024 | Buy | +800 | $13.39 | $10.71K | 620,193 |
| William P. Scully 10% owner | Dec 31, 2024 | Buy | +30,000 | $12.99 | $389.70K | 650,193 |
| William P. Scully 10% owner | Dec 20, 2024 | Buy | +2,000 | $15.91 | $31.82K | 618,693 |
| William P. Scully 10% owner | Dec 20, 2024 | Gift | −500 | – | – | 618,193 |
| William P. Scully 10% owner | Dec 20, 2024 | Gift | −40,000 | – | – | 59,000 |
| William P. Scully 10% owner | Dec 19, 2024 | Gift | −681,000 | – | – | 616,693 |
| William P. Scully 10% owner | Dec 18, 2024 | Gift | +430,000 | – | – | 1,224,257 |
| William P. Scully 10% owner | Dec 18, 2024 | Buy | +73,436 | $13.93 | $1.02M | 1,297,693 |
| Karin L. Walker Chief Accounting Officer | Jan 24, 2024 | Option exercise | +5,000 | $13.53 | $67.65K | 5,000 |
| Karin L. Walker Chief Accounting Officer | Jan 24, 2024 | Sale(10b5-1 plan) | −5,000 | $34.00 | $170.00K | 0 |
| Karin L. Walker Chief Accounting Officer | Dec 20, 2023 | Sale(10b5-1 plan) | −3,322 | $37.45 | $124.41K | 0 |
| Karin L. Walker Chief Accounting Officer | Dec 20, 2023 | Option exercise | +5,000 | $13.53 | $67.65K | 5,000 |
Awards, option exercises, tax withholding and gifts are shown alongside open-market buys and sales. Each name links to the filing on SEC EDGAR.
Planned insider sales
Notices of proposed sale filed on Form 144 before shares are sold
| Seller | Filed | Shares | Market value | Planned sale | Acquired through |
|---|---|---|---|---|---|
| John Isaacs Michael Officer | Jul 29, 2026 | 8,386 | $71.06K | Jul 29, 2026 | Restricted Stock |
| Kingston Anne Officer | Jul 29, 2026 | 7,662 | $64.92K | Jul 29, 2026 | Restricted Stock |
| Michael J. Malecek Previous Officer | Jun 9, 2026 | 80,000 | $740.00K | Jun 9, 2026 | EMPLOYEE RESTRICTED SHARE UNIT AWARD |
| Karin L. Walker Officer | Jan 24, 2024 | 5,000 | $170.00K | Jan 24, 2024 | Exercise of stock options |
| Karin L. Walker Officer | Dec 20, 2023 | 5,000 | $186.45K | Dec 20, 2023 | Exercise of Stock Options |
| Karin L. Walker Officer | Nov 30, 2023 | 5,000 | $170.00K | Nov 30, 2023 | Exercise of stock options |
| Karin L. Walker Officer | Oct 25, 2023 | 5,000 | $206.35K | Oct 25, 2023 | Exercise of Stock Options |
| Brandon S. Smith Officer | Oct 11, 2023 | 4,000 | $189.16K | Oct 11, 2023 | Exercise of Stock Options |
| Carol D. Karp Officer | Oct 4, 2023 | 5,000 | $237.00K | Oct 4, 2023 | Exercise of Stock Options |
| Michael J. Malecek Officer | Sep 27, 2023 | 5,000 | $241.05K | Sep 27, 2023 | Exercise of Stock Option |
| Sanjiv Patel Director | Sep 25, 2023 | 35,000 | $1.75M | Sep 25, 2023 | STOCK OPTION EXERCISE |
| Walker Karin Officer | Sep 19, 2023 | 5,000 | $261.81K | Sep 19, 2023 | Stock Option Exercise |
| Brandon S. Smith Officer | Sep 13, 2023 | 4,000 | $221.56K | Sep 13, 2023 | Exercise of stock options |
| Hideki Garren Officer | Sep 13, 2023 | 2,000 | $110.78K | Sep 13, 2023 | Exercise of Stock Options |
| Carol D. Karp Officer | Sep 6, 2023 | 5,000 | $273.05K | Sep 6, 2023 | Exercise of stock options |