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Insider Trading Intelligence
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William P. Scully

PRTA
10% OWNER · PROTHENA CORP PUBLIC LTD CO · CIK 0001045463
FILING MIX · LIFETIME63%/37%
BUYS
12
SELLS
7
TOTAL VALUE
$5.85M
COMPANIES
1
ACTIVE SINCE
Dec 2024
HOLDINGS NOW
756,000
AVG SELL PX
TRADE KIND
SHOWING 19 / 19
Trades · vs SPY
Loading price series…
Performance · forward returns vs SPY
6 backtested trades · 8 horizons · 6 pending
Forward-return performance of every backtestable P/S trade by William P. Scully, measured at 8 horizons from 7 days to 2 years. Deduped per economic event so co-filings count once. Excess return = trade return minus SPY return over the same window.
HORIZONTRADESWIN RATEINSIDER RETURNSPY RETURNMEAN EXCESSMEDIAN EXCESST-STAT
7d6+83.33%+7.70%+1.41%+6.29%+1.73%
14d6+33.33%+1.24%+0.38%+0.86%-7.86%
30d6+83.33%+5.62%+2.97%+2.66%+2.90%
60d6+83.33%+10.14%+1.43%+8.71%+12.77%
90d6+16.67%-10.26%-4.71%-5.55%-6.38%
180d6+0.00%-55.44%+4.95%-60.38%-61.91%
1y6+0.00%-30.25%+16.77%-47.03%-47.75%
2y6(6 pending)
How to read this: Insider Returnis the average raw return of the filer's trades over the horizon. SPY Return is what SPY did over those same windows — reference only, not a comparison. The headline alpha number is Mean Excess = Insider − SPY; green means the filer beat SPY, red means they trailed it. Win rate is the share of individual trades where the filer beat SPY. T-statvalues above 2 mean the alpha is unlikely to be chance given the sample size. "Pending" counts trades where the horizon hasn't elapsed yet; their stats are not included in the row average.
Holdings over time
PRTA · 756,000 shares · as of Jun 16, 2026
0324,423648,847973,2701,297,69320252026SHARES HELD
Trading cadence · quarterly flow
BUY SELL
2024
2025
2025
2025
2025
2026
2026
FLOW · 12 buys / 7 sellsCOVERAGE · 7 quarters
Form 4 filings · all activity
COMPANYTYPESHARESPRICEVALUEHELD AFTERTRADE DATEFILEDDETAILS
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
20,000$7.90$158.0K756,000Jun 16, 2026Jun 18, 2026View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
325,000736,000Jun 15, 2026Jun 16, 2026View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
125,000$8.17$1.02M1,061,000Jun 11, 2026Jun 12, 2026View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
50,000$9.31$465.3K936,000Jun 4, 2026Jun 5, 2026View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
50,000$9.43$471.3K886,000Jun 2, 2026Jun 3, 2026View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
100,000$9.81$981.3K836,000May 22, 2026May 26, 2026View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
12,00047,000Jan 15, 2025May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
100,000$12.79$1.28M735,993Jan 14, 2025May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
1,000635,993Jan 3, 2025May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
13,200636,993Jan 2, 2025May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
30,000$12.99$389.6K650,193Dec 31, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
800$13.39$10.7K620,193Dec 31, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
1,200$13.37$16.0K619,393Dec 31, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
40,00059,000Dec 20, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
2,000$15.91$31.8K618,693Dec 20, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
500618,193Dec 20, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
SALEGRANT
Gift
681,000616,693Dec 19, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASE
73,436$13.93$1.02M1,297,693Dec 18, 2024May 2, 2025View →
PRTA
PROTHENA CORP PUBLIC LTD CO
PURCHASEGRANT
Gift
430,0001,224,257Dec 18, 2024May 2, 2025View →
Other insiders · PRTA
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About this filer
CIK 0001045463
ROLE
10% Owner
PRIMARY
PRTA
COMPANIES
1
ACTIVE SINCE
Dec 2024
MARKETPEEL · /INSIDER/0001045463DATA · SEC EDGAR · FORM 4 · CONSOLIDATED TAPE
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