Sun Kang sold ~$772K in Amprius Technologies, Inc. stock
Amprius Technologies, Inc. (AMPX) · Chief Executive Officer · Data via SEC EDGAR Form 4
Price Performance · 10 days before → 90 days after trade
▲ = insider buy date
90-day return
+59.2%vs SPY +4.5%
Trade Details · Public SEC Filing
Insider
Sun Kang
Role
Chief Executive Officer
Transaction
Open-Market Sale
Approx. Value
~$772K
Trade Date
Aug 21, 2025
Company
Amprius Technologies, Inc.
Ticker
AMPXSource
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.
~$772K sale
A significant position. Insiders who invest $500K+ of their own money typically have strong views on their company's near-term outlook.
Chief Executive Officer
CEOs have the deepest knowledge of company operations. Academic research shows CEO purchases outperform other insider trades by a wide margin.
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.
+59.2% in 90 days (S&P 500: +4.5%)
This trade beat the S&P 500 by 54.7 percentage points over 90 days. We track performance on every insider trade so you can see who consistently outperforms.
How good is Sun Kang at picking stocks?
Full track record: win rate, average return, and performance vs S&P 500
Sun Kang wasn't the only one selling.
3 insiders at Amprius Technologies, Inc. traded within the same 30-day window.
See who else bought · FreeOn August 21, 2025, Sun Kang — Chief Executive Officer of Amprius Technologies, Inc. — filed a Form 4 with the SEC disclosing an open-market sale of approximately ~$772K in Amprius Technologies, Inc. (AMPX) stock.
This transaction was part of a cluster — 3 insiders at Amprius Technologies, 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.
In the 90 days following this trade, AMPX returned +59.2% versus +4.5% 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
More AMPX Insider Activity
DIXON DONALD R
Jun 15, 2026
~$1.5M
VS
DIXON DONALD R
Jun 9, 2026
~$765K
STRONG
DIXON DONALD R
May 27, 2026
~$914K
STRONG
Sun Kang
May 21, 2026
~$1.0M
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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