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SEC EDGARSEP 211 min read$PRTA

SCULLY WILLIAM P purchased $843K of PRTA

SCULLY WILLIAM P purchased 100,000 shares of PROTHENA CORP PUBLIC LTD CO (PRTA) at $8.43 ($0.84M total) on 2026-09-18.

Original reporting
SEC EDGAR · SCULLY WILLIAM P
Published Sep 21, 2026, 8:23 PM UTC
Analysis
AlphAI AI DeskAI-generated
Added to AlphAI Sep 21, 2026, 9:02 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
Neutral
high confidence
Mentioned
$PRTA
Relevance
6/10
AlphAI data visualization · based on SEC EDGAR
Decision brief

The 30-second read

$PRTANeutralLow
01

Why it matters

The insider purchase adds modest shares to a 10% owner, unlikely to influence market perception.

02

Market read

Routine insider purchase with limited trading relevance.

03

What to watch

Potential upcoming clinical milestones for Prothena that may drive future insider activity.

Relevance 6/10Novelty 4/10Timing: filed after market close on 2026-09-21

Background

SEC Form 4 filing discloses insider transactions.

Company-level read

Ticker impact

$PRTANeutralHigh confidence
Context

Insider William Scully purchased 100,000 shares of Prothena for $843,460 on 2026-09-18.

Expected impact

No significant price impact expected.

Evidence & confidence

The purchase is small relative to market cap and follows a recent insider filing.

Market effects

Sector

None; the filing is company‑specific.

Regional

None; limited to Prothena shareholders.

Global

Low; no broader market effect.

Counterpoint

What could challenge this read

The purchase could signal confidence, but size is too small to affect valuation.

Key entities

  • Company
    Prothena Corp Public Ltd Co

    Biopharmaceutical company listed as PRTA.

  • Insider
    William Scully

    10% owner who purchased shares.

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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