Prothena Corporation plc (PRTA)

Prothena Corporation plc at a glance — key fundamentals, SEC filings, insider buying and selling, and earnings dates.

Prothena Corporation plc (PRTA) is a Biotechnology company based in IE with a market capitalization of $458.1M. Revenue declined 92.8% year-over-year and free cash flow was negative at -$163.7M. This page tracks PRTA's SEC filings, insider buying and selling, earnings dates, and key fundamentals in one place.

IE · 163 employees · IPO Dec 18, 2012

Valuation

Valuation & price

$9.76as of May 17, 2026· -15.2% vs 52w high

P/E ratio

Latest-FY diluted EPS

1.63

P/B ratio

Market cap ÷ book equity

Dividend yield

Price — last 12 months

$11.19$8.93$6.68Jul 25Jan 26Jul 26
$6.6852-week range$11.51
Loading valuation history…

Fundamentals

Key fundamentals

$458.1M

Market cap

-92.8%

Revenue growth (YoY)

61.8%

Gross margin

-$163.7M

Free cash flow (USD)

-$293.7M

Net debt

Net cash position

0.1%

Share dilution

1/5

Graham criteria passed

Defensive-investor screen

Healthcare

Sector

Trajectory

Long-term trends

Revenue by year

20162025

$1.1M$9.7M

Free cash flow by year

20162025

-$133.9M-$163.7M

Gross margin by year

20212025

100.0%61.8%

Value screen

Graham defensive-investor tests

Computing the scorecard — refreshing any stale inputs…

5

Insider buys · 90 days

0

Insider sells · 90 days

Earnings

Last report: 10-Q filed May 7, 2026

Next expected: not yet scheduled

On the tape

Recent SEC & insider activity

  • Insider buyJun 18, 2026Filing

    Insider Buy $158KSCULLY WILLIAM P · 10% Owner · $158K

  • Insider buyJun 12, 2026Filing

    Insider Buy $1.0MSCULLY WILLIAM P · 10% Owner · $1M

  • Insider buyJun 5, 2026Filing

    Insider Buy $465KSCULLY WILLIAM P · 10% Owner · $465.3K

  • Insider buyJun 3, 2026Filing

    Insider Buy $471KSCULLY WILLIAM P · 10% Owner · $471.3K

  • Insider buyMay 26, 2026Filing

    Insider Buy $981KSCULLY WILLIAM P · 10% Owner · $981.3K

  • 8-K eventMay 15, 2026Filing

    Annual Shareholder Meeting

  • 8-K eventMay 7, 2026Filing

    Earnings Release

  • Quarterly reportMay 7, 2026Filing

    10-Q Filed

Questions

Frequently asked questions

What is Prothena Corporation plc's market cap?

Prothena Corporation plc (PRTA) has a market capitalization of $458.1M.

What is PRTA's P/E ratio?

A meaningful P/E ratio is not available for PRTA — the company's latest fiscal-year earnings per share is zero, negative, or not yet cached.

What is PRTA's price-to-book (P/B) ratio?

PRTA trades at 1.63 times book value per share.

Are insiders buying PRTA stock?

Yes — SEC Form 4 filings show 5 open-market insider buys and 0 sells at Prothena Corporation plc in the last 90 days.

Same arena

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Timeline

Every filing, insider trade & earnings on a price-anchored timeline

Filing Analyzer

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News

Latest press coverage in one feed

Data: SEC EDGAR filings and cached fundamental data; prices and ratios use the most recent cached quote and statements (may lag by up to a day). Educational and research purposes only. Not investment advice.