Updated Jul 16, 2026
Stefan Constantin Ionel has filed 2 SEC Form 4 filings across 1 company in the last 90 days — selling. Lifetime open-market sales: $8.19M.
Constantin Ionel Stefan is the Chief Technology Officer at Amprius Technologies, Inc., a company specializing in silicon anodes for lithium-ion batteries. He has been involved in multiple SEC filings related to his role but has not reported any stock transactions.
| Role | Chief Technology Officer |
|---|---|
| Notability | 20/100 |
| Date | Ticker | Company | Code | Shares | Price | Value |
|---|---|---|---|---|---|---|
| 2026-05-28 | AMPX | Amprius Technologies, Inc. | S — Open-market sale | 3.2K | $17.19 | $55K |
| 2026-05-26 | AMPX | Amprius Technologies, Inc. | S — Open-market sale | 28.8K | $14.79 | $426K |
| 2026-03-06 | AMPX | Amprius Technologies, Inc. | A — Grant or award | 110.0K | $0.00 | |
| 2026-02-24 | AMPX | Amprius Technologies, Inc. | S — Open-market sale | 25.4K | $10.16 | $258K |
| 2026-01-30 | AMPX | Amprius Technologies, Inc. | S — Open-market sale [10b5-1] | 39.7K | $12.00 | $476K |
| 2026-01-30 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 39.6K | $0.05 | $2K |
| 2026-01-30 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 90 | $0.62 | $56 |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | S — Open-market sale [10b5-1] | 1.6K | $12.00 | $19K |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 1.6K | $0.05 | $80 |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | S — Open-market sale [10b5-1] | 492.8K | $12.04 | $5.93M |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 166.1K | $0.05 | $8K |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 72.8K | $0.45 | $33K |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 253.9K | $0.05 | $13K |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | S — Open-market sale [10b5-1] | 73.3K | $12.00 | $879K |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 15.9K | $0.05 | $794 |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 15.8K | $0.05 | $792 |
| 2026-01-23 | AMPX | Amprius Technologies, Inc. | M — Option exercise [10b5-1] | 41.6K | $0.62 | $26K |
| 2025-08-21 | AMPX | Amprius Technologies, Inc. | S — Open-market sale | 19.2K | $6.82 | $131K |
| 2024-11-22 | AMPX | Amprius Technologies, Inc. | S — Open-market sale | 8.6K | $1.96 | $17K |
Constantin Ionel Stefan is the Chief Technology Officer at Amprius Technologies, Inc., a company specializing in silicon anodes for lithium-ion batteries. He has been involved in multiple SEC filings related to his role but has not reported any stock transactions.…
2 primary Form 4 filings in the last 90 days, covering 1 company.
Recorded transactions: 0 open-market purchases () and 9 open-market sales ($8.19M) across all tracked filings.
All Form 4 filings, transaction values, and 10b5-1 plan flags are listed on this page and updated in real time as new SEC EDGAR filings are processed.
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