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Insider Sale Insider Sale August 18, 2025

Smiley Joshua L sold ~$661K in Zai Lab Limited stock

Zai Lab Limited (ZLAB)  ·  Data via SEC EDGAR Form 4

Verity Signals Research Published Updated

= insider buy date

ZLAB price after insider trade by Smiley Joshua L

Insider

Smiley Joshua L

Role

Transaction

Open-Market Sale

Approx. Value

~$661K

Trade Date

Aug 18, 2025

Company

Zai Lab Limited

Ticker

ZLAB

Source

SEC EDGAR Form 4

Strong conviction signal

Scored above average across multiple factors. Roughly 15% of insider trades qualify as Strong.

~$661K sale

A significant position. Insiders who invest $500K+ of their own money typically have strong views on their company's near-term outlook.

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.

SJ

How good is Smiley Joshua L at picking stocks?

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3

Smiley Joshua L wasn't the only one selling.

3 insiders at Zai Lab Limited traded within the same 30-day window.

See who else bought · Free

On August 18, 2025, Smiley Joshua L — a corporate insider at Zai Lab Limited — filed a Form 4 with the SEC disclosing an open-market sale of approximately ~$661K in Zai Lab Limited (ZLAB) stock.

This transaction was part of a cluster — 3 insiders at Zai Lab Limited 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.

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 Strong
Trade size ~$661K
Insider role Insider
Cluster 3 insiders

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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