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SEC EDGARSEP 291 min read$PRTA

SCULLY WILLIAM P purchased $890K of PRTA (indirect holdings)

SCULLY WILLIAM P purchased 103,500 indirectly-held shares of PROTHENA CORP PUBLIC LTD CO (PRTA) at $8.60 ($0.89M total) on 2026-09-28.

Original reporting
SEC EDGAR · SCULLY WILLIAM P
Published Sep 29, 2026, 9:37 PM UTC
Analysis
AlphAI AI DeskAI-generated
Added to AlphAI Sep 29, 2026, 9:42 PM UTC. Informational, not investment advice.
How this was made
AlphAI summarizes source reporting and applies a structured AI analysis for relevance, timing, sentiment and ticker impact. Always verify material claims with the original publisher.
About AlphAI AI DeskScoring methodologyReport an issue
AlphAI market briefInsider activity
Primary signal
$PRTA
Bullish
high confidence
Mentioned
$PRTA
Relevance
6/10
AlphAI data visualization · based on SEC EDGAR
Decision brief

The 30-second read

$PRTABullishMed
01

Why it matters

The purchase may signal confidence in upcoming milestones, prompting short sellers to cover.

02

Market read

Insider buying in a small‑cap biotech can move the stock and attract trader attention.

03

What to watch

Potential upcoming financing rounds or clinical trial outcomes not disclosed.

Relevance 6/10Novelty 8/10Timing: after-hours today

Background

SEC Form 4 filing provides the first public disclosure of the insider transaction.

Company-level read

Ticker impact

$PRTABullishHigh confidence
Context

Form 4 shows insider William Scully purchased 103,500 shares for $889,872, increasing his stake to 187,000 shares (10% owner).

Expected impact

likely upward pressure as market prices in insider confidence

Evidence & confidence

The purchase is sizable relative to float and comes from a 10% owner, indicating material support for the stock.

Market effects

Sector

Minimal; reflects confidence in Prothena's biotech pipeline.

Regional

None

Global

Low

Counterpoint

What could challenge this read

Insider buying could be a defensive move ahead of upcoming dilution or negative news.

Key entities

  • Company
    Prothena Corp Public Ltd Co

    Biotech firm listed on NASDAQ (PRTA).

  • Insider
    William Scully

    10% owner executing an open‑market purchase.

Read at source← All news

Full insider trading history

This story covers one filing. See everything behind it: every insider buy and sell on record, 10b5-1 plans, late filings, and which officers and directors are trading.

PRTA insider trading history →

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