William P Scully

10% owner · Prothena

William P Scully (10% owner) filed 15 Form 4 reports in the trailing twelve months (15 purchases, 0 sales), most often in Prothena Corporation plc (PRTA). Across 13 priced purchase filings, the average 21-session return was +2.1% from execution and -0.6% from disclosure (delay-adjusted; derived). The largest single filing was $1.8M of PRTA (215,000 sh across 2 lots, as filed), executed Oct 7. Data as of Nov 8 2026.

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Return, ttmiAverage return per filing, trailing twelve months

+2.1%

avg across 13 priced filings

Delay-adjustediThe same average, entered at disclosure dates

-0.6%

same 13 filings, from disclosure

Filings, ttm

15 buys · 0 sells

Median delay

execution → disclosure

Volume, ttmiDollar value disclosed in the trailing twelve months

$12.0M

shares × price, as filed

Last traded

Oct 23

Filed Oct 26

Median ADV $4.9M across their filed names

Impact on $10,000 · 12M

$7,900 (-21.0%)

S&P 500 $10,907 (+9.1%) · 30.1 pts behind

William P Scully S&P 500

Derived: compounded across filings from disclosure dates · past 12 months

Open performance→

Volume by month

Buys $14.7M Sells $0

Shares × price, as filed · by filing month · past 24 months

Sectors filed on

Healthcare 15 filings

Sector per market data · by filing · past 12 months

Most traded names

PRTA

Prothena Corporation plc PRTA · 16 buys · 0 sells 16 filings

Recent filings

PRTAPURCHASE Prothena Corporation plc View filing → $1.2M
150,000 sh across 2 lots
Exec Oct 22
Filed Oct 26 · 4:20 PM ET PRTAPURCHASE Prothena Corporation plc View filing → $835K
100,000 sh × $8.35
Exec Oct 13
Filed Oct 15 · 4:21 PM ET PRTAPURCHASE Prothena Corporation plc View filing → $1.8M
215,000 sh across 2 lots
Exec Oct 7
Filed Oct 9 · 9:43 AM ET PRTAPURCHASE Prothena Corporation plc View filing → $857K
100,000 sh × $8.57
Exec Oct 2
Filed Oct 6 · 1:53 PM ET PRTAPURCHASE Prothena Corporation plc View filing → $1.4M
162,000 sh × $8.68
Exec Sep 29
Filed Sep 30 · 5:10 PM ET PRTAPURCHASE Prothena Corporation plc View filing → $890K
103,500 sh × $8.60
Exec Sep 28
Filed Sep 29 · 5:37 PM ET PRTAPURCHASE Prothena Corporation plc View filing → $843K
100,000 sh × $8.43
Exec Sep 18
Filed Sep 21 · 4:23 PM ET PRTAPURCHASE Prothena Corporation plc View filing → $256K
27,000 sh × $9.47
Exec Sep 2
Filed Sep 3 · 6:23 PM ET More filings →