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buyModerate

William P Scully bought $890k of PRTA

owner at PROTHENA CORP PUBLIC LTD CO. 103,500 shares at an average of $8.60, traded Sep 28, 2026, filed Sep 29, 2026.

Conviction score
49
Value
$890k
103,500 shares
Holdings after
187,000
+124% from before
From 52-week low
+10%
low $7.91, close $8.72
From 52-week high
-24%
high $11.51, as of Sep 28, 2026

Score components

  • Role
    10% owner
    +12
  • Trade size
    $890k at market
    +23
  • Relative to holdings
    Holdings up 124%
    +10
  • Price context
    24% below the 52-week high
    +4
  • Cluster
    No other insider buying within 14 days
    0
  • Repeat buying
    3 buys in 90 days
    +5
  • Track record
    Too few past buys to judge (0 with prices)
    0
  • Outside holder
    A 10% owner who is not an officer or director
    -5

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.

PRTAOct 9, 2026 · close 8.84
Since filing Sep 29, 2026: +0.7%SPY +1.8% · excess -1.1%

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 0001045463-26-000017, as filed. Open on EDGAR

DateTransactionSharesPriceValueHoldings afterFiled
Sep 28, 2026POpen-market purchase
Ordinary Shares, par value $0.01 per shareindirect: By Manatee Equity Fund LLC
+103,500$8.60$890k187,00014 d ago

Related signals

Other insiders at PROTHENA CORP PUBLIC LTD CO and this insider’s other filings.

ScoreCompanyInsiderValueHoldingsFiled
61Notable
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%
52Moderate
PRTAbuy
PROTHENA CORP PUBLIC LTD CO
William P Scully
owner
$843k
100,000 shares
+12%
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
PRTAsell 210b5-1
PROTHENA CORP PUBLIC LTD CO
Michael John Isaacs
General Counsel & Company Sec.
$71k
8,386 shares
-19%
16Weak
PRTAsell 210b5-1
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.

William P Scully bought $890k of PRTA | InsiderTell