Insider · CIK 0001940928
Constantin Ionel Stefan
officer
Files at AMPX (Amprius Technologies, Inc.). First filing Nov 22, 2024, latest Feb 24, 2026.
Track record
Not enough history
Fewer than three past buys with six months of prices.
Median 6-month excess
-
after past buys, n = 0
Hit rate
-
past buys that beat the index over 6 months
Open-market trades
0 / 9
$0 bought, $10M sold
Where the trades landed
Last year at the company this insider has traded most, with each buy and sell on the bar it happened.
AMPX: Amprius Technologies, Inc.
AMPXOct 9, 2026 · close 9.44
Daily candles, adjusted for splits and dividends. Green arrows are insider buys, red are sells, sized by value. Click a marked bar to open the signal.Charts by TradingView Lightweight Charts™
Signals
This insider’s open-market buys and sells, scored.
| Score | Company | Value | Holdings | Price context | Filed |
|---|---|---|---|---|---|
| 36Weak | Amprius Technologies, Inc. | $258k 25,366 shares | -3% | +473% from low-31% from high | |
| 6Weak | Amprius Technologies, Inc. | $476k 39,690 shares | -5% | +573% from low-18% from high | |
| 33Weak | Amprius Technologies, Inc. | $6.8M 567,707 shares | -69% | +533% from low-23% from high | |
| 10Weak | Amprius Technologies, Inc. | $2.1M 198,255 shares | -21% | +589% from low-22% from high | |
| 36Weak | Amprius Technologies, Inc. | $252k 25,024 shares | -3% | +509% from low-31% from high | |
| 41Moderate | Amprius Technologies, Inc. | $131k 19,159 shares | -2% | +738% from low-22% from high | |
| 37Weak | Amprius Technologies, Inc. | $50k 20,366 shares | -2% | +199% from low-37% from high | |
| 35Weak | Amprius Technologies, Inc. | $28k 9,066 shares | -2% | +270% from low-22% from high | |
| 30Weak | Amprius Technologies, Inc. | $17k 8,575 shares | -2% | - |
Planned sales
Form 144 notices this insider filed before selling restricted or control stock, newest first.
| Filed | Company | Shares | Value | Sale date | Past 3 months |
|---|---|---|---|---|---|
| Nov 21, 2024 | AMPX Amprius Technologies, Inc. | 8,575 0.01% of outstanding | $17k | Nov 21, 2024 | none |
Transactions
Every row this insider has filed, newest first.
| Date | Company | Transaction | Shares | Price | Value | Holdings after | Filed |
|---|---|---|---|---|---|---|---|
| Mar 4, 2026 | AMPX Amprius Technologies, Inc. | AGrant or award Common stock | +110,000 | $0.00 | $0 | 833,330 | Mar 6, 2026 |
| Feb 23, 2026 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock | -25,366 | $10.16 | $258k | 723,330 | Feb 24, 2026 |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +90 | $0.62 | $56 | 748,786 | Jan 30, 2026 |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +39,600 | $0.05 | $1,980 | 788,386 | Jan 30, 2026 |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock10b5-1 | -39,690 | $12.00 | $476k | 748,696 | Jan 30, 2026 |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -90 | $0.00 | $0 | 0 | Jan 30, 2026 |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -39,600 | $0.00 | $0 | 0 | Jan 30, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +41,563 | $0.62 | $26k | 790,259 | Jan 23, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +15,834 | $0.05 | $792 | 806,093 | Jan 23, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +15,883 | $0.05 | $794 | 821,976 | Jan 23, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock10b5-1 | -73,280 | $12.00 | $879k | 748,696 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +253,928 | $0.05 | $13k | 1,002,624 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +72,795 | $0.45 | $33k | 1,075,419 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +166,104 | $0.05 | $8,305 | 1,241,523 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock10b5-1 | -492,827 | $12.04 | $5.9M | 748,696 | Jan 23, 2026 |
| Jan 23, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +1,600 | $0.05 | $80 | 750,296 | Jan 23, 2026 |
| Jan 23, 2026 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock10b5-1 | -1,600 | $12.00 | $19k | 748,696 | Jan 23, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -41,563 | $0.00 | $0 | 90 | Jan 23, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -15,834 | $0.00 | $0 | 295,128 | Jan 23, 2026 |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -15,883 | $0.00 | $0 | 166,104 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -253,928 | $0.00 | $0 | 41,200 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -72,795 | $0.00 | $0 | 0 | Jan 23, 2026 |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -166,104 | $0.00 | $0 | 0 | Jan 23, 2026 |
| Jan 23, 2026 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -1,600 | $0.00 | $0 | 39,600 | Jan 23, 2026 |
| Dec 11, 2025 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock10b5-1 | +125,000 | $0.05 | $6,250 | 946,951 | Dec 15, 2025 |
| Dec 11, 2025 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock10b5-1 | -198,255 | $10.51 | $2.1M | 748,696 | Dec 15, 2025 |
| Dec 11, 2025 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative10b5-1 | -125,000 | $0.00 | $0 | 310,962 | Dec 15, 2025 |
| Nov 21, 2025 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock | -25,024 | $10.08 | $252k | 821,951 | Nov 25, 2025 |
| Aug 21, 2025 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock | -19,159 | $6.82 | $131k | 846,975 | Aug 25, 2025 |
| May 21, 2025 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock | -20,366 | $2.43 | $50k | 866,134 | May 23, 2025 |
| Mar 19, 2025 | AMPX Amprius Technologies, Inc. | AGrant or award Common stock | +461,540 | $0.00 | $0 | 886,500 | Mar 21, 2025 |
| Mar 14, 2025 | AMPX Amprius Technologies, Inc. | MOption exercise Common stock | +3,471 | $0.98 | $3,402 | 424,960 | Mar 18, 2025 |
| Mar 14, 2025 | AMPX Amprius Technologies, Inc. | MOption exercise Stock Option (right to buy)derivative | -3,471 | $0.00 | $0 | 0 | Mar 18, 2025 |
| Feb 21, 2025 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock | -9,066 | $3.13 | $28k | 421,489 | Feb 24, 2025 |
| Nov 21, 2024 | AMPX Amprius Technologies, Inc. | SOpen-market sale Common stock | -8,575 | $1.96 | $17k | 430,555 | Nov 22, 2024 |
| Oct 23, 2024 | AMPX Amprius Technologies, Inc. | AGrant or award Stock Option (right to buy)derivative | +3,471 | - | - | 3,471 | Oct 25, 2024 |
| Oct 23, 2024 | AMPX Amprius Technologies, Inc. | AGrant or award Stock Option (right to buy)derivative | +41,653 | - | - | 41,653 | Oct 25, 2024 |
| Oct 23, 2024 | AMPX Amprius Technologies, Inc. | AGrant or award Stock Option (right to buy)derivative | +139,613 | - | - | 139,613 | Oct 25, 2024 |
Not investment advice. Scores and forward returns are decision support built from public SEC filings and past prices; they describe what happened after comparable filings, not what will happen after this one. Do your own research and size your risk.