RA CAPITAL MANAGEMENT, L.P. purchased ~$200M in 89bio Inc stock
89bio Inc (ETNB) · Data via SEC EDGAR Form 4
Price Performance · 10 days before → 90 days after trade
▲ = insider buy date
90-day return
-16.8%
Trade Details · Public SEC Filing
Insider
RA CAPITAL MANAGEMENT, L.P.
Role
—
Transaction
Open-Market Purchase
Approx. Value
~$200M
Trade Date
Jan 30, 2025
Company
89bio Inc
Ticker
ETNBSource
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.
~$200M purchase
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.
2 insiders traded in the same window
When multiple insiders independently buy within 30 days, it's called a cluster. Studies show clustered insider purchases outperform solo trades significantly, because several people with inside knowledge are reaching the same conclusion.
-16.8% in 90 days
Measured from trade date to 90 days later. We track the performance of every insider trade to identify which insiders consistently make profitable moves.
How good is RA CAPITAL MANAGEMENT, L.P. at picking stocks?
Full track record: win rate, average return, and performance vs S&P 500
RA CAPITAL MANAGEMENT, L.P. wasn't the only one buying.
2 insiders at 89bio Inc traded within the same 30-day window.
See who else bought · FreeOn January 30, 2025, RA CAPITAL MANAGEMENT, L.P. — a corporate insider at 89bio Inc — filed a Form 4 with the SEC disclosing an open-market purchase of approximately ~$200M in 89bio Inc (ETNB) stock.
This transaction was part of a cluster — 2 insiders at 89bio Inc made open-market purchases within the same 30-day window. Cluster activity from multiple independent insiders is one of the most studied patterns in insider trading research.
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, ETNB returned -16.8%
VeritySignals Conviction Analysis
Full Conviction Analysis
Sign up free to see signal strength details, or upgrade for the full 15-factor breakdown.
Get notified the next time RA CAPITAL MANAGEMENT, L.P. trades
Free alerts · No credit card · Instant notification
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
More ETNB Insider Activity
McWherter Charles
Jan 21, 2025
~$50M
STRONG
PALEKAR ROHAN
Dec 5, 2024
~$119K
STRONG
PALEKAR ROHAN
Jul 7, 2021
~$118K
STRONG
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.
Never miss a signal
Get notified when high-conviction insiders buy. Free account, no credit card.
Sign up free