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buyNotable

William P Scully bought $1.8M of PRTA

owner at PROTHENA CORP PUBLIC LTD CO. 215,000 shares at an average of $8.47, traded Oct 7, 2026, filed Oct 9, 2026.

Conviction score
61
Value
$1.8M
215,000 shares
Holdings after
529,000
+68% from before
From 52-week low
+7%
low $7.91, close $8.48
From 52-week high
-26%
high $11.51, as of Oct 7, 2026

Score components

  • Role
    10% owner
    +12
  • Trade size
    $1.8M at market
    +25
  • Relative to holdings
    Holdings up 68%
    +10
  • Price context
    7% above the 52-week low; 26% below the 52-week high
    +14
  • Cluster
    No other insider buying within 14 days
    0
  • Repeat buying
    6 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

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 0001045463-26-000020, as filed. Open on EDGAR

DateTransactionSharesPriceValueHoldings afterFiled
Oct 7, 2026POpen-market purchase
Ordinary Shares, par value $0.01 per shareindirect: By Spouse
+125,000$8.40$1.1M439,0004 d ago
Oct 8, 2026POpen-market purchase
Ordinary Shares, par value $0.01 per shareindirect: By Spouse
+90,000$8.57$771k529,0004 d ago

Related signals

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

ScoreCompanyInsiderValueHoldingsFiled
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%
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 $1.8M of PRTA | InsiderTell