Nasdaq · CIK 0001559053
PRTA PROTHENA CORP PUBLIC LTD CO
Insider trading from SEC Form 4. Last filing 4 d ago. Close $8.84 on Oct 9, 2026, +12% from the 52-week low and -23% from the high.
In brief
PROTHENA CORP PUBLIC LTD CO (PRTA) has 62 SEC Form 4 filings on file from 16 insiders, the latest filed on Oct 9, 2026. In the last 90 days insiders made 8 open-market buys worth $6.8M and 2 open-market sells worth $136k, net +$6.7M.
21 open-market trades have been scored at PRTA. The newest: William P Scully (10% owner) bought $1.8M of stock on Oct 7, 2026, filed Oct 9, 2026, scored 61 (notable). The largest of the 21 shown: EcoR1 Capital, LLC (10% owner) sold $51M on May 2, 2025, scored 57 (moderate). 2 insiders sold within 14 days of each other around Jul 29, 2026.
8 Form 144 notices of planned sales are on file, the latest filed Jul 29, 2026.
Last 90 days
Net insider value
+$6.7M
more bought than sold
Buys
8
$6.8M by 1 insider
Sells
2
$136k by 2 insiders
Insiders on file
16
with a Form 4 at this company
Price and insider trades, last year
PRTAOct 9, 2026 · close 8.84
Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value. Click a marked bar to open the signal.Charts by TradingView Lightweight Charts™
Signals
Open-market buys and sells at PROTHENA CORP PUBLIC LTD CO, scored.
| Score | Insider | Value | Holdings | Price context | Filed |
|---|---|---|---|---|---|
| 61Notable | William P Scully owner buy | $1.8M 215,000 shares | +68% | +7% from low-26% from high | |
| 55Moderate | William P Scully owner buy | $857k 100,000 shares | +47% | +6% from low-27% from high | |
| 51Moderate | William P Scully owner buy | $1.4M 162,000 shares | +312% | +11% from low-24% from high | |
| 49Moderate | William P Scully owner buy | $890k 103,500 shares | +124% | +10% from low-24% from high | |
| 52Moderate | William P Scully owner buy | $843k 100,000 shares | +12% | +8% from low-25% from high | |
| 29Weak | William P Scully owner buy | $256k 27,000 shares | +3% | +22% from low-16% from high | |
| 36Weak | William P Scully owner buy | $439k 50,000 shares | +7% | +14% from low-22% from high | |
| 30Weak | William P Scully owner buy | $323k 37,500 shares | +5% | +16% from low-24% from high | |
| 16Weak | Michael John Isaacs General Counsel & Company Sec. sell | $71k 8,386 shares | -19% | +26% from low-26% from high | |
| 16Weak | Anne Evans Kingston Chief Strategy Officer sell | $65k 7,662 shares | -12% | +26% from low-26% from high | |
| 27Weak | William P Scully owner buy | $158k 20,000 shares | +3% | +46% from low-28% from high | |
| 44Moderate | William P Scully owner buy | $1.0M 125,000 shares | +13% | +63% from low-28% from high | |
| 36Weak | William P Scully owner buy | $465k 50,000 shares | +6% | +90% from low-20% from high | |
| 36Weak | William P Scully owner buy | $471k 50,000 shares | +6% | +97% from low-20% from high | |
| 35Weak | William P Scully owner buy | $981k 100,000 shares | +14% | +115% from low-15% from high | |
| 57Moderate | EcoR1 Capital, LLC owner sell | $51M 6,279,684 shares | -54% | 0% from low-62% from high | |
| 53Moderate | William P Scully owner buy | $2.7M 207,436 shares | +17% | 0% from low-46% from high | |
| 12Weak | Karin L Walker Chief Accounting Officer sell | $186k 5,000 shares | -100% | +14% from low-53% from high | |
| 11Weak | Karin L Walker Chief Accounting Officer sell | $170k 5,000 shares | -100% | +1% from low-59% from high | |
| 20Weak | Karin L Walker Chief Accounting Officer sell | $205k 5,000 shares | -100% | 0% from low-50% from high | |
| 25Weak | Brandon S. Smith Chief Operating Officer sell | $187k 4,000 shares | -100% | +4% from low-40% from high |
Planned sales
Form 144 notices filed before a sale of restricted or control stock, newest first. The sale itself usually reaches a Form 4 within days. All planned sales
| Filed | Seller | Shares | Value | Sale date | Past 3 months |
|---|---|---|---|---|---|
| Jul 29, 2026 | MICHAEL JOHN ISAACS Officer | 8,386 0.02% of outstanding | $71k | Jul 29, 2026 | none |
| Jul 29, 2026 | ANNE KINGSTON Officer | 7,662 0.01% of outstanding | $65k | Jul 29, 2026 | none |
| Jun 9, 2026 | MALECEK MICHAEL J Previous Officer | 80,000 0.15% of outstanding | $740k | Jun 9, 2026 | none |
| Jan 24, 2024 | Walker Karin L Officer | 5,000 0.01% of outstanding | $170k | Jan 24, 2024 | $561k |
| Dec 20, 2023 | Walker Karin L Officer | 5,000 0.01% of outstanding | $186k | Dec 20, 2023 | $375k |
| Nov 30, 2023 | Walker Karin L Officer | 5,000 0.01% of outstanding | $170k | Nov 30, 2023 | $467k |
| Oct 25, 2023 | Walker Karin L Officer | 5,000 0.01% of outstanding | $206k | Oct 25, 2023 | $548k |
| Oct 11, 2023 | Smith Brandon S. Officer | 4,000 0.01% of outstanding | $189k | Oct 11, 2023 | $727k |
Transactions
The newest 50 of 106 rows filed, every code.
| Date | Insider | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|---|
| Oct 7, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per shareindirect: By Spouse | +125,000 | $8.40 | $1.1M | 439,000 | 4 d ago |
| Oct 8, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per shareindirect: By Spouse | +90,000 | $8.57 | $771k | 529,000 | 4 d ago |
| Oct 2, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per shareindirect: By Spouse | +100,000 | $8.57 | $857k | 314,000 | 7 d ago |
| Sep 29, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per shareindirect: By Spouse | +162,000 | $8.68 | $1.4M | 214,000 | 13 d ago |
| Sep 28, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per shareindirect: By Manatee Equity Fund LLC | +103,500 | $8.60 | $890k | 187,000 | 14 d ago |
| Sep 18, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +100,000 | $8.43 | $843k | 927,000 | 22 d ago |
| Sep 2, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +27,000 | $9.47 | $256k | 827,000 | 40 d ago |
| Aug 20, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +50,000 | $8.79 | $439k | 800,000 | Aug 21, 2026 |
| Aug 17, 2026 | William P Scully owner | GGift Ordinary Shares, par value $0.01 per share | +336,000 | $0.00 | $0 | 1,377,553 | Aug 18, 2026 |
| Aug 18, 2026 | William P Scully owner | GGift Ordinary Shares, par value $0.01 per share | -627,553 | $0.00 | $0 | 750,000 | Aug 18, 2026 |
| Aug 10, 2026 | William P Scully owner | GGift Ordinary Shares, par value $0.01 per share | +251,553 | $0.00 | $0 | 1,041,553 | Aug 11, 2026 |
| Aug 7, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +34,000 | $8.62 | $293k | 790,000 | Aug 10, 2026 |
| Aug 7, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per shareindirect: By Manatee Equity Fund LLC | +3,500 | $8.62 | $30k | 83,500 | Aug 10, 2026 |
| Jul 28, 2026 | Michael John Isaacs General Counsel & Company Sec. | FTax withholding Ordinary Shares, par value $0.01 per share10b5-1 | -4,694 | $8.56 | $40k | 44,131 | Jul 30, 2026 |
| Jul 28, 2026 | Gene G. Kinney President and CEO | MOption exercise Ordinary Shares, par value $0.01 per share | +84,000 | - | - | 152,793 | Jul 30, 2026 |
| Jul 28, 2026 | Tran Nguyen Chief Strategy Officer and CFO | MOption exercise Ordinary Shares, par value $0.01 per share | +57,000 | - | - | 97,205 | Jul 30, 2026 |
| Jul 28, 2026 | Wagner M. Zago Chief Scientific Officer | MOption exercise Ordinary Shares, par value $0.01 per share | +51,000 | - | - | 85,000 | Jul 30, 2026 |
| Jul 28, 2026 | Brandon S. Smith Chief Operating Officer | MOption exercise Ordinary Shares, par value $0.01 per share | +78,000 | - | - | 130,000 | Jul 30, 2026 |
| Jul 28, 2026 | Chad J. Swanson Chief Development Officer | MOption exercise Ordinary Shares, par value $0.01 per share | +51,000 | - | - | 85,000 | Jul 30, 2026 |
| Jul 28, 2026 | Anne Evans Kingston Chief Strategy Officer | FTax withholding Ordinary Shares, par value $0.01 per share10b5-1 | -3,498 | $8.56 | $30k | 63,444 | Jul 30, 2026 |
| Jul 28, 2026 | Karin L Walker Chief Accounting Officer | MOption exercise Ordinary Shares, par value $0.01 per share | +15,000 | - | - | 25,000 | Jul 30, 2026 |
| Jul 28, 2026 | Karin L Walker Chief Accounting Officer | DDisposition to issuer Ordinary Shares, par value $0.01 per share | -15,000 | $8.56 | $128k | 10,000 | Jul 30, 2026 |
| Jul 28, 2026 | Wagner M. Zago Chief Scientific Officer | DDisposition to issuer Ordinary Shares, par value $0.01 per share | -51,000 | $8.56 | $437k | 34,000 | Jul 30, 2026 |
| Jul 28, 2026 | Gene G. Kinney President and CEO | DDisposition to issuer Ordinary Shares, par value $0.01 per share | -84,000 | $8.56 | $719k | 68,793 | Jul 30, 2026 |
| Jul 28, 2026 | Tran Nguyen Chief Strategy Officer and CFO | DDisposition to issuer Ordinary Shares, par value $0.01 per share | -57,000 | $8.56 | $488k | 40,205 | Jul 30, 2026 |
| Jul 28, 2026 | Brandon S. Smith Chief Operating Officer | DDisposition to issuer Ordinary Shares, par value $0.01 per share | -78,000 | $8.56 | $668k | 52,000 | Jul 30, 2026 |
| Jul 28, 2026 | Chad J. Swanson Chief Development Officer | DDisposition to issuer Ordinary Shares, par value $0.01 per share | -40,800 | $8.56 | $349k | 44,200 | Jul 30, 2026 |
| Jul 29, 2026 | Michael John Isaacs General Counsel & Company Sec. | SOpen-market sale Ordinary Shares, par value $0.01 per share10b5-1 | -8,386 | $8.47 | $71k | 35,745 | Jul 30, 2026 |
| Jul 29, 2026 | Anne Evans Kingston Chief Strategy Officer | SOpen-market sale Ordinary Shares, par value $0.01 per share10b5-1 | -7,662 | $8.47 | $65k | 55,782 | Jul 30, 2026 |
| Jul 28, 2026 | Karin L Walker Chief Accounting Officer | MOption exercise Restricted Stock Unitsderivative | -15,000 | $0.00 | $0 | 0 | Jul 30, 2026 |
| Jul 28, 2026 | Wagner M. Zago Chief Scientific Officer | MOption exercise Restricted Stock Unitsderivative | -51,000 | $0.00 | $0 | 0 | Jul 30, 2026 |
| Jul 28, 2026 | Gene G. Kinney President and CEO | MOption exercise Restricted Stock Unitsderivative | -84,000 | $0.00 | $0 | 0 | Jul 30, 2026 |
| Jul 28, 2026 | Tran Nguyen Chief Strategy Officer and CFO | MOption exercise Restricted Stock Unitsderivative | -57,000 | $0.00 | $0 | 0 | Jul 30, 2026 |
| Jul 28, 2026 | Brandon S. Smith Chief Operating Officer | MOption exercise Restricted Stock Unitsderivative | -78,000 | $0.00 | $0 | 0 | Jul 30, 2026 |
| Jul 28, 2026 | Chad J. Swanson Chief Development Officer | FTax withholding Ordinary Shares, par value $0.01 per share | -3,467 | $8.56 | $30k | 40,733 | Jul 30, 2026 |
| Jul 28, 2026 | Chad J. Swanson Chief Development Officer | MOption exercise Restricted Stock Unitsderivative | -51,000 | $0.00 | $0 | 0 | Jul 30, 2026 |
| Jun 16, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +20,000 | $7.90 | $158k | 756,000 | Jun 18, 2026 |
| Jun 15, 2026 | William P Scully owner | GGift Ordinary Shares, par value $0.01 per share | -325,000 | $0.00 | $0 | 736,000 | Jun 16, 2026 |
| Jun 11, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +125,000 | $8.17 | $1.0M | 1,061,000 | Jun 12, 2026 |
| Jun 4, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +50,000 | $9.31 | $465k | 936,000 | Jun 5, 2026 |
| Jun 2, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +50,000 | $9.43 | $471k | 886,000 | Jun 3, 2026 |
| May 22, 2026 | William P Scully owner | POpen-market purchase Ordinary Shares, par value $0.01 per share | +100,000 | $9.81 | $981k | 836,000 | May 26, 2026 |
| May 15, 2026 | Richard T Collier director | AGrant or award Stock Option (Right to Buy)derivative | +27,000 | $0.00 | $0 | 27,000 | May 15, 2026 |
| May 15, 2026 | Shane Cooke director | AGrant or award Stock Option (Right to Buy)derivative | +27,000 | $0.00 | $0 | 27,000 | May 15, 2026 |
| May 15, 2026 | William H. Dunn Jr. director | AGrant or award Stock Option (Right to Buy)derivative | +27,000 | $0.00 | $0 | 27,000 | May 15, 2026 |
| May 15, 2026 | Lars Ekman director | AGrant or award Stock Option (Right to Buy)derivative | +27,000 | $0.00 | $0 | 27,000 | May 15, 2026 |
| May 15, 2026 | Dennis J. Selkoe director | AGrant or award Stock Option (Right to Buy)derivative | +27,000 | $0.00 | $0 | 27,000 | May 15, 2026 |
| May 15, 2026 | Daniel G Welch director | AGrant or award Stock Option (Right to Buy)derivative | +27,000 | $0.00 | $0 | 27,000 | May 15, 2026 |
| Apr 10, 2026 | Anne Evans Kingston Chief Strategy Officer | AGrant or award Stock Option (Right to Buy)derivative | +100,000 | $0.00 | $0 | 100,000 | Apr 10, 2026 |
| Mar 3, 2026 | Gene G. Kinney President and CEO | AGrant or award Stock Option (Right to Buy)derivative | +520,000 | $0.00 | $0 | 520,000 | Mar 5, 2026 |
50 of 106 rows shown.
Insiders
Everyone who has filed a Form 4 here.
- Richard T Collierdirector
- Shane Cookedirector
- William H. Dunn Jr.director
- EcoR1 Capital, LLCowner, director
- Lars Ekmandirector
- Michael John IsaacsGeneral Counsel & Company Sec.
- Anne Evans KingstonChief Strategy Officer
- Gene G. KinneyPresident and CEO
- Tran NguyenChief Strategy Officer and CFO
- William P Scullyowner
- Dennis J. Selkoedirector
- Brandon S. SmithChief Operating Officer
- Chad J. SwansonChief Development Officer
- Daniel G Welchdirector
- Karin L WalkerChief Accounting Officer
- Wagner M. ZagoChief Scientific Officer
Questions about PRTA
Answered from the filings on this page, as of the latest one.
Are insiders buying PRTA?
As of Oct 9, 2026, SEC Form 4 filings show 8 open-market buys worth $6.8M by 1 insider and 2 open-market sells worth $136k by 2 insiders at PROTHENA CORP PUBLIC LTD CO in the last 90 days, net +$6.7M. Only purchases (code P) and sales (code S) count; grants, option exercises and tax withholding do not.
Who was the last insider to trade PRTA on the open market?
William P Scully (10% owner) bought $1.8M of PRTA on Oct 7, 2026 and filed the Form 4 on Oct 9, 2026. InsiderTell scored 61 (notable).
How many insiders file Form 4 at PROTHENA CORP PUBLIC LTD CO?
16 people have filed a Form 4 at PROTHENA CORP PUBLIC LTD CO, among them Richard T Collier (director), Shane Cooke (director), William H. Dunn Jr. (director). Officers, directors and holders of more than 10% of a share class must report their trades within two business days.
Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.