Amprius Technologies, Inc. (AMPX)
$9.93+$0.04 (+0.40%) TodayExtended Hours
Kang Sun - Director
Constantin Ionel Stefan - OfficerKang Sun - DirectorAmprius Technologies Inc is engaged in the production of silicon anodes for high-energy-density lithium-ion batteries. The company develops, manufactures and markets lithium-ion batteries for mobility applications, including the aviation, electric vehicle (EV) and light electric vehicle (LEV) industries. The company's batteries are used for existing and emerging aviation applications, including unmanned aerial systems, such as drones and high-altitude pseudo satellites. Its silicon anodes are a direct drop-in replacement of the graphite anode in traditional lithium-ion batteries, and its manufacturing processes leverage the manufacturing processes for conventional lithium-ion batteries and the related supply chain.
| Form 4 transaction type | Transactions | Shares | Total value |
|---|---|---|---|
| Open-market sale | 7 | 250,311 | $3.54M |
| Grant or award | 5 | 42,038 | |
| Bona-fide gift | 7 | 119,558 |
Dollar totals are shown for open-market purchases and sales only. Grants, option exercises, gifts and tax withholding are reported by share count because they are not trades at a market price.
51 Form 4 filings on record, the earliest from Oct 25, 2024, newest first. Filing history page 2 of 2.
| Date | Insider | Transaction | Security | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Kang Sun - Director | Option exercise | Common stock | 850,338 | $2.50 | $2.13M | |
| Kang Sun - Director | Option exercise | Common stock | 100,210 | $1.78 | $178K | |
| Kang Sun - Director | Open-market sale | Common stock | 950,548 | $11.07 | $10.52M | |
| Kang Sun - Director | Option exercise | Common stock | 43,185 | $1.78 | $77K | |
| Kang Sun - Director | Open-market sale | Common stock | 43,185 | $11.03 | $476K | |
| Kang Sun - Director | Option exercise | Stock Option (right to buy) | 850,338 | $0.00 | - | |
| Kang Sun - Director | Option exercise | Stock Option (right to buy) | 100,210 | $0.00 | - | |
| Kang Sun - Director | Option exercise | Stock Option (right to buy) | 43,185 | $0.00 | - | |
| Kang Sun - Director | Option exercise | Common stock | 180,802 | $0.62 | $112K | |
| Kang Sun - Director | Option exercise | Common stock | 208,264 | $2.44 | $508K | |
| Kang Sun - Director | Option exercise | Common stock | 117,201 | $2.50 | $293K | |
| Kang Sun - Director | Open-market sale | Common stock | 506,267 | $10.10 | $5.11M | |
| Kang Sun - Director | Option exercise | Stock Option (right to buy) | 180,802 | $0.00 | - | |
| Kang Sun - Director | Option exercise | Stock Option (right to buy) | 208,264 | $0.00 | - | |
| Kang Sun - Director | Option exercise | Stock Option (right to buy) | 117,201 | $0.00 | - | |
| Constantin Ionel Stefan - Officer | Open-market sale | Common stock | 25,024 | $10.08 | $252K | |
| Kang Sun - Officer | Open-market sale | Common stock | 68,655 | $10.08 | $692K | |
| Kang Sun - Officer | Option exercise | Stock Option (right to buy) | 202,934 | $0.00 | - | |
| Kang Sun - Officer | Option exercise | Stock Option (right to buy) | 727,950 | $0.00 | - | |
| Kang Sun - Officer | Option exercise | Stock Option (right to buy) | 27,463 | $0.00 | - | |
| Kang Sun - Officer | Option exercise | Stock Option (right to buy) | 41,653 | $0.00 | - | |
| Kang Sun - Officer | Option exercise | Common stock | 202,934 | $0.98 | $199K | |
| Kang Sun - Officer | Option exercise | Common stock | 727,950 | $0.05 | $36K | |
| Kang Sun - Officer | Option exercise | Common stock | 27,463 | $0.62 | $17K | |
| Kang Sun - Officer | Option exercise | Common stock | 41,653 | $0.62 | $26K | |
| Kang Sun - Officer | Open-market sale | Common stock | 1,000,000 | $10.60 | $10.60M | |
 Ricardo C. Rodriguez - Officer | Grant or award | Common stock | 200,000 | $0.00 | - | |
| Kang Sun - Officer | Open-market sale | Common stock | 65,654 | $6.82 | $448K | |
| Constantin Ionel Stefan - Officer | Open-market sale | Common stock | 19,159 | $6.82 | $131K | |
| Sandra Wallach - Officer | Open-market sale | Common stock | 28,390 | $6.82 | $194K | |
| Kathleen A. Bayless - Director | Grant or award | Common stock | 44,444 | $0.00 | - | |
| Steven Chu - Director | Grant or award | Common stock | 44,444 | $0.00 | - | |
| Donald R. Dixon - Director | Grant or award | Common stock | 44,444 | $0.00 | - | |
| Constantin Ionel Stefan - Officer | Open-market sale | Common stock | 8,575 | $1.96 | $17K | |
| Jonathan Bornstein - Officer | Open-market sale | Common stock | 133,536 | $1.92 | $257K | |
| Jonathan Bornstein - Officer | Open-market sale | Common stock | 15,000 | $1.96 | $29K | |
| Jonathan Bornstein - Officer | Open-market sale | Common stock | 18,170 | $1.96 | $36K | |
| Kang Sun - Officer | Open-market sale | Common stock | 33,779 | $1.96 | $66K | |
| Sandra Wallach - Officer | Open-market sale | Common stock | 17,158 | $1.96 | $34K | |
| Steven Chu - Director | Grant or award | Stock Option (right to buy) | 173,554 | - | - | |
| Steven Chu - Director | Grant or award | Stock Option (right to buy) | 173,554 | - | - | |
| Jonathan Bornstein - Officer | Grant or award | Stock Option (right to buy) | 3,471 | - | - | |
| Jonathan Bornstein - Officer | Grant or award | Stock Option (right to buy) | 27,768 | - | - | |
| Constantin Ionel Stefan - Officer | Grant or award | Stock Option (right to buy) | 3,471 | - | - | |
| Constantin Ionel Stefan - Officer | Grant or award | Stock Option (right to buy) | 41,653 | - | - | |
| Constantin Ionel Stefan - Officer | Grant or award | Stock Option (right to buy) | 139,613 | - | - | |
| Amprius, Inc. - 10% Owner | Other | Common stock | 5,500,000 | - | - | |
| Amprius, Inc. - 10% Owner | Other | Common stock | 57,195,926 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 208,265 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 208,264 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 41,653 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 202,934 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 1,171,476 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 1,974,502 | - | - | |
| Kang Sun - Officer | Grant or award | Stock Option (right to buy) | 967,539 | - | - |
A Form 144 is notice of an INTENDED sale, not a completed one. It often precedes the Form 4 that reports the trade actually happening.
| Filed | Filer | Relationship | Shares | Market value | Notice |
|---|---|---|---|---|---|
| KANG SUN | Director | 62,101 | $642K | View on EDGAR | |
| Constantin Ionel Stefan | OFFICER | 29,681 | $307K | View on EDGAR | |
| THOMAS M STEPIEN | OFFICER, DIRECTOR | 23,529 | $243K | View on EDGAR |
Amprius Technologies, Inc. (AMPX) had 9 insider filings in the last 90 days, with the most recent on 2026-08-25. The full record for AMPX runs to 51 Form 4 filings, the earliest from 2024-10-25. InsiderAlpha tracks every Form 4, Form 144, and 8-K filing in real time.
No insider purchases of AMPX were filed in the last 90 days.
7 insider sales of AMPX were filed in the last 90 days, totaling $3.54M.
This page tracks AMPX Form 4 insider transactions, Form 144 sale notices, and 8-K material event disclosures in one timeline. Annual 10-K and quarterly 10-Q reports live on the company's SEC EDGAR page.
Create a free InsiderAlpha account and press Watch on this page to add AMPX to your watchlist. A free account also opens the full scored daily plan with every past day and 3 months of price history. No card is required. Sign up at https://insideralpha.ai/register.
Every Form 4 below links to the original document on SEC EDGAR, so the numbers on this page can be checked against the filing they came from.
Real-time Form 4 alerts, AI-scored daily trade ideas and 10b5-1 plan flags.
