Updated Jul 16, 2026 · Last SEC filing 2026-06-16
Amprius Technologies, Inc. (AMPX) has filed 15 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-06-16. 5 Form 8-K material event filings were reported by AMPX in the last 90 days. 9 Form 144 notices of proposed sale were filed for AMPX stock. InsiderAlpha tracks every AMPX SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.
| SIC classification | Miscellaneous Electrical Machinery, Equipment & Supplies (SIC 3690) |
|---|---|
| SEC CIK | 0001899287 |
| Form 4 filings (90d) | 15 |
|---|---|
| Form 8-K filings (90d) | 5 |
| Form 144 notices (90d) | 9 |
| Latest Form 4 filing | 2026-06-16 |
| Date | Insider | Role | Transaction | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| DIXON DONALD R | Director | S — Open-market sale | 85.0K | $17.17 | $1.46M | SEC | |
| Chu Steven | Director | A — Grant or award | 10.4K | $0.00 | — | SEC | |
| SATTERTHWAITE LIVINGSTON | Director | A — Grant or award | 10.4K | $0.00 | — | SEC | |
| DIXON DONALD R | Director | A — Grant or award | 10.4K | $0.00 | — | SEC | |
| BAYLESS KATHLEEN A | Director | A — Grant or award | 10.4K | $0.00 | — | SEC | |
| DIXON DONALD R | Director | S — Open-market sale | 40.0K | $19.13 | $765K | SEC | |
| Stepien Thomas M | Chief Executive Officer | G — Bona-fide gift | 30.4K | $0.00 | — | SEC | |
| Stepien Thomas M | Chief Executive Officer | G — Bona-fide gift | 36.9K | $0.00 | — | SEC | |
| Stepien Thomas M | Chief Executive Officer | G — Bona-fide gift | 36.9K | $0.00 | — | SEC | |
| Stepien Thomas M | Chief Executive Officer | S — Open-market sale | 2.0K | $20.97 | $42K | SEC | |
| Stefan Constantin Ionel | Chief Technology Officer | S — Open-market sale | 3.2K | $17.19 | $55K | SEC | |
| Stepien Thomas M | Chief Executive Officer | S — Open-market sale | 4.4K | $17.19 | $75K | SEC | |
| Sun Kang | Director | S — Open-market sale | 356 | $17.19 | $6K | SEC | |
| DIXON DONALD R | Director | S — Open-market sale | 17.9K | $17.90 | $320K | SEC | |
| Stepien Thomas M | Chief Executive Officer | S — Open-market sale | 60.7K | $14.79 | $898K | SEC |
All transactions sourced from SEC EDGAR Form 4 filings for Amprius Technologies, Inc. (AMPX). Updated in real time as new filings are submitted to the SEC.
| Insider | Form 4 filings | Total transaction value |
|---|---|---|
| Stepien Thomas M | 7 | $1.01M |
| DIXON DONALD R | 4 | $2.54M |
| Sun Kang | 3 | $1.01M |
| Stefan Constantin Ionel | 2 | $481K |
| BAYLESS KATHLEEN A | 1 | — |
Form 144 must be filed before insiders sell restricted or control stock above SEC thresholds. A cluster of Form 144 notices often precedes a wave of insider distribution.
SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in AMPX insider filings:
| P | Open-market purchase by the insider |
|---|---|
| S | Open-market sale by the insider |
| A | Grant, award, or other acquisition from the issuer |
| M | Exercise or conversion of derivative security (e.g. options) |
| F | Payment of exercise price or tax liability via share withholding |
| G | Bona-fide gift of securities |
| D | Disposition to the issuer (e.g. share buyback participation) |
| J | Other acquisition or disposition |
| X | Exercise of in-the-money or at-the-money derivative security |
| C | Conversion of derivative security |
| V | Transaction voluntarily reported earlier than required |
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