EcoR1 Capital, LLC sold ~$51M in Prothena Corporation plc stock
Prothena Corporation plc (PRTA) · Data via SEC EDGAR Form 4
Price Performance · 10 days before → 90 days after trade
▲ = insider buy date
90-day return
-19.2%vs SPY +11.9%
Trade Details · Public SEC Filing
Insider
EcoR1 Capital, LLC
Role
—
Transaction
Open-Market Sale
Approx. Value
~$51M
Trade Date
May 2, 2025
Company
Prothena Corporation plc
Ticker
PRTASource
SEC EDGAR Form 4
Why This Trade Stands Out
Strong conviction signal
Scored above average across multiple factors. Roughly 15% of insider trades qualify as Strong.
~$51M sale
Trades over $1M are rare. When insiders put this much of their own money on the line, they tend to have high conviction in their company's direction.
-19.2% in 90 days (S&P 500: +11.9%)
This trade underperformed the S&P 500 by 31.0 percentage points. Not every insider trade wins. We track all of them so you can focus on the insiders with the best records.
How good is EcoR1 Capital, LLC at picking stocks?
Full track record: win rate, average return, and performance vs S&P 500
On May 2, 2025, EcoR1 Capital, LLC — a corporate insider at Prothena Corporation plc — filed a Form 4 with the SEC disclosing an open-market sale of approximately ~$51M in Prothena Corporation plc (PRTA) stock.
Under Section 16(a) of the Securities Exchange Act of 1934, corporate insiders must report all open-market stock transactions to the SEC within two business days. These filings — known as Form 4s — are publicly available on the SEC's EDGAR database. VeritySignals filters and scores the full Form 4 stream to surface high-conviction signals like this one.
In the 90 days following this trade, PRTA returned -19.2% versus +11.9% for the S&P 500 over the same period.
VeritySignals Conviction Analysis
Full Conviction Analysis
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All data sourced from publicly available SEC Form 4 filings via EDGAR · Not financial advice · Past performance does not guarantee future results.
At a Glance
How to Read Insider Trades
What is this?
When company executives buy or sell their own stock, they must report it to the SEC within 2 days. These public filings reveal what the people who know the company best are doing with their own money.
Why does it matter?
Insiders can sell for many reasons (taxes, diversification, expenses), but they generally only buy for one: they think the stock is going up. That's why insider purchases are more predictive than sales.
What makes a trade "strong"?
We score trades on 15+ factors: the insider's role (CEO > director), trade size relative to their salary, whether other insiders also bought (clusters), and historical accuracy of the insider.
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