StockCIK 1899287
Amprius Technologies, Inc. (AMPX): Insider Trades and Fund Holdings
In the past 12 months, Amprius Technologies, Inc. insiders reported 0 open-market purchases worth $0 and 4 sales worth $1.27M; 0 of the sales were reported as made under a 10b5-1 trading plan.
0Insider buys, 12 months
$0Bought by insiders, 12 months
$1.27MSold by insiders, 12 months
1Tracked funds holding
Recent insider trades
Open-market purchases (code P) and sales (code S) from Form 4. Grants, option exercises and gifts are not shown. Latest filing: Aug 25, 2026.
| Filed | Insider | Type | Value |
|---|---|---|---|
| Aug 25 | Kang SunDirector | ▼ SELL | $642K |
| Aug 25 | Constantin Ionel StefanCTO | ▼ SELL | $307K |
| Aug 25 | Thomas M. StepienCEO | ▼ SELL | $243K |
| Aug 25 | Thomas M. StepienCEO | ▼ SELL | $80K |
Source: SEC Form 4 filings, retrieved Oct 28, 2026. How we read filings
Insiders who traded in the past year
| Insider | Role | Buys | Bought | Sells | Sold |
|---|---|---|---|---|---|
| Kang Sun | Director | 0 | $0 | 1 | $642K |
| Constantin Ionel Stefan | CTO | 0 | $0 | 1 | $307K |
| Thomas M. Stepien | CEO | 0 | $0 | 2 | $324K |
Tracked funds that report AMPX
From each fund's latest 13F. Holdings are as of quarter end and are filed up to 45 days later.
| Fund | Shares | Value | Change |
|---|---|---|---|
| Renaissance Technologies | 1,408,925 | $19.5M | ▲ +291.9% |
Source: SEC Form 13F-HR filings, retrieved Oct 28, 2026. How we read filings
Reading these numbers
Insiders sell for many reasons: taxes, diversification, a house. Purchases with their own money are rarer and are usually read as more informative. A Form 4 is due within two business days of the trade. How to read a Form 4 →