Constantin Ionel Stefan insider trades: Amprius Technologies (AMPX) stock sales
Trades on the price chart
Daily close, with an arrow on each day they bought or sold
Companies
Where Constantin reports to the SEC
Open-market buys and sales
15 trades reported on SEC Form 4, newest first
| Date | Stock | Type | Shares | Price | Value | Holding | Reported |
|---|---|---|---|---|---|---|---|
| Aug 21, 2026 | AMPX | ↓ Sell | 29,681 | $10.34 | $307K | Direct | Aug 25, 2026 (4d) |
| May 27, 2026 | AMPX | ↓ Sell | 3,208 | $17.19 | $55K | Direct | May 28, 2026 (1d) |
| May 21, 2026 | AMPX | ↓ Sell | 28,812 | $14.79 | $426K | Direct | May 26, 2026 (5d) |
| Feb 23, 2026 | AMPX | ↓ Sell | 25,366 | $10.16 | $258K | Direct | Feb 24, 2026 (1d) |
| Jan 28, 2026 | AMPX | ↓ Sell | 39,690 | $12.00 | $476K | Direct | Jan 30, 2026 (2d) |
| Jan 23, 2026 | AMPX | ↓ Sell | 567,707 | $12.03 | $6.8M | Direct | Jan 23, 2026 (0d) |
| Dec 11, 2025 | AMPX | ↓ Sell | 198,255 | $10.51 | $2.1M | Direct | Dec 15, 2025 (4d) |
| Nov 21, 2025 | AMPX | ↓ Sell | 25,024 | $10.08 | $252K | Direct | Nov 25, 2025 (4d) |
| Aug 21, 2025 | AMPX | ↓ Sell | 19,159 | $6.82 | $131K | Direct | Aug 25, 2025 (4d) |
| May 21, 2025 | AMPX | ↓ Sell | 20,366 | $2.43 | $50K | Direct | May 23, 2025 (2d) |
| Feb 21, 2025 | AMPX | ↓ Sell | 9,066 | $3.13 | $28K | Direct | Feb 24, 2025 (3d) |
| Nov 21, 2024 | AMPX | ↓ Sell | 8,575 | $1.96 | $17K | Direct | Nov 22, 2024 (1d) |
| Aug 21, 2024 | AMPX | ↓ Sell | 8,800 | $1.04 | $9K | Direct | Aug 22, 2024 (1d) |
| May 22, 2024 | AMPX | ↓ Sell | 9,393 | $1.34 | $13K | Direct | May 24, 2024 (2d) |
| Sep 15, 2023 | AMPX | ↓ Sell | 80,000 | $3.75 | $300K | Direct | Sep 18, 2023 (3d) |
Each row is one filing's trades in one stock, summed. Shares and prices are as filed, before any later stock split.
Other AMPX insiders
Open-market trades in the last 12 months
About Constantin Ionel Stefan's insider trades
Constantin Ionel Stefan is Chief Technology Officer at Amprius Technologies (AMPX). Since Sep 15, 2023, Constantin has reported no open-market purchases and 15 sales worth $11.2M on SEC Form 4. In the last 12 months: 8 sales ($10.7M).
Their filings also include option exercises (6 filings), grants and awards (5 filings), shares withheld for taxes (1 filing). These aren't open-market trades and aren't counted above.
How to read insider trades
Officers, directors and owners of more than 10% of a company must report trades in its stock on SEC Form 4, usually within two business days. Purchases with their own money are the stronger signal: insiders sell for many reasons (taxes, diversification, a house), but buy for one. See every AMPX insider trade, the latest insider trades across the market, or cluster buys, when several insiders buy the same stock within days.