William P Scully bought $843k of PRTA
owner at PROTHENA CORP PUBLIC LTD CO. 100,000 shares at an average of $8.43, traded Sep 18, 2026, filed Sep 21, 2026.
Score components
- +12Role10% owner
- +23Trade size$843k at market
- +3Relative to holdingsHoldings up 12%
- +14Price context8% above the 52-week low; 25% below the 52-week high
- 0ClusterNo other insider buying within 14 days
- +5Repeat buying2 buys in 90 days
- 0Track recordToo few past buys to judge (0 with prices)
- -5Outside holderA 10% owner who is not an officer or director
What happened after comparable buys
Same side and tier, against the S&P 500, at 1, 3 and 6 months. Shown to Pro users; the whole table is on the backtest page.
Price around the trade, and since
From a quarter before the trade to today. The arrow is the trade, the circle the day the filing reached EDGAR, which is the first day anyone outside could act; the dotted line is the S&P 500 rebased to that day's close.
Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value; the dashed line is the close on the filing day, the dotted line SPY rebased to it.Charts by TradingView Lightweight Charts™
Rows in this filing
Every transaction in Form 4 0001045463-26-000016, as filed. Open on EDGAR
| Date | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|
| Sep 18, 2026 | POpen-market purchase Ordinary Shares, par value $0.01 per share | +100,000 | $8.43 | $843k | 927,000 | 24 d ago |
Related signals
Other insiders at PROTHENA CORP PUBLIC LTD CO and this insider’s other filings.
| Score | Company | Insider | Value | Holdings | Filed |
|---|---|---|---|---|---|
| Pro nowfree Oct 16, 2026 | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $1.8M 215,000 shares | +68% | |
| 55Moderate | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $857k 100,000 shares | +47% | |
| 51Moderate | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $1.4M 162,000 shares | +312% | |
| 49Moderate | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $890k 103,500 shares | +124% | |
| 29Weak | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $256k 27,000 shares | +3% | |
| 36Weak | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $439k 50,000 shares | +7% | |
| 30Weak | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $323k 37,500 shares | +5% | |
| 16Weak | PROTHENA CORP PUBLIC LTD CO | Michael John Isaacs General Counsel & Company Sec. | $71k 8,386 shares | -19% | |
| 16Weak | PROTHENA CORP PUBLIC LTD CO | Anne Evans Kingston Chief Strategy Officer | $65k 7,662 shares | -12% | |
| 27Weak | PRTAbuy PROTHENA CORP PUBLIC LTD CO | William P Scully owner | $158k 20,000 shares | +3% |
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.