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Insider Buy Mega Buy ($1M+) January 23, 2026

Heron Patrick J purchased ~$36M in Mirum Pharmaceuticals, Inc. stock

Mirum Pharmaceuticals, Inc. (MIRM)  ·  Data via SEC EDGAR Form 4

Verity Signals Research Published Updated

= insider buy date

MIRM price after insider trade by Heron Patrick J

Insider

Heron Patrick J

Role

Transaction

Open-Market Purchase

Approx. Value

~$36M

Trade Date

Jan 23, 2026

Company

Mirum Pharmaceuticals, Inc.

Ticker

MIRM

Source

SEC EDGAR Form 4

Very Strong conviction signal

Scored in the top tier across multiple factors. Fewer than 5% of insider trades receive this rating.

~$36M 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.

HP

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On January 23, 2026, Heron Patrick J — a corporate insider at Mirum Pharmaceuticals, Inc. — filed a Form 4 with the SEC disclosing an open-market purchase of approximately ~$36M in Mirum Pharmaceuticals, Inc. (MIRM) 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.

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.

Signal strength Very Strong
Trade size ~$36M
Insider role Insider

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.

Read our full methodology →

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