Harler Mary Beth sold ~$70K in IGM Biosciences, Inc. stock
IGM Biosciences, Inc. (IGMS) · Data via SEC EDGAR Form 4
Price Performance · 10 days before → 90 days after trade
▲ = insider buy date
Trade Details · Public SEC Filing
Insider
Harler Mary Beth
Role
—
Transaction
Open-Market Sale
Approx. Value
~$70K
Trade Date
Jul 23, 2025
Company
IGM Biosciences, Inc.
Ticker
IGMSSource
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.
~$70K sale
A personal investment by a corporate insider. Even smaller trades can be meaningful when combined with other factors like timing and role.
3 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.
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Harler Mary Beth wasn't the only one selling.
3 insiders at IGM Biosciences, Inc. traded within the same 30-day window.
See who else bought · FreeOn July 23, 2025, Harler Mary Beth — a corporate insider at IGM Biosciences, Inc. — filed a Form 4 with the SEC disclosing an open-market sale of approximately ~$70K in IGM Biosciences, Inc. (IGMS) stock.
This transaction was part of a cluster — 3 insiders at IGM Biosciences, Inc. made open-market sales 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.
VeritySignals 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
More IGMS Insider Activity
BEHRENS M KATHLEEN
Jun 26, 2023
~$1.7M
STRONG
Schwarzer Fred
Dec 16, 2022
~$613K
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BEHRENS M KATHLEEN
Apr 1, 2022
~$1.9M
STRONG
BEHRENS M KATHLEEN
Dec 11, 2020
~$33M
VS
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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