Constantin Ionel Stefan
CIK: 0001940928
Transaction Breakdown
High conviction signal
Position reduction
Derivative conversions
Compensation grants
Gifts, tax withholding, conversions, dispositions to the issuer and other codes
Companies & Roles (1)
Amprius Technologies, Inc.
Discretionary Trading P&L
Holdings
Transaction History (30 total)
- Aug 21, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct29.7K shares at avg. $10.34$307K - May 27, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct3.2K shares at avg. $17.19$55K - May 21, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct28.8K shares at avg. $14.79$426K - Mar 4, 2026AMPX
Amprius Technologies, Inc.
Award(A)Direct110K shares- - Feb 23, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct25.4K shares at avg. $10.16$258K - Jan 28, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct39.6K shares at avg. $0.05$2K - Jan 28, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct90 shares at avg. $0.62$55.8 - Jan 28, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct39.7K shares at avg. $12.00$476K - Jan 23, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct1.6K shares at avg. $0.05$80 - Jan 23, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct1.6K shares at avg. $12.00$19K - Jan 22, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct166.1K shares at avg. $0.05$8K - Jan 22, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct492.8K shares at avg. $12.04$5.9M - Jan 22, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct253.9K shares at avg. $0.05$13K - Jan 22, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct72.8K shares at avg. $0.45$33K - Jan 21, 2026AMPX
Amprius Technologies, Inc.
Sale(S)Direct73.3K shares at avg. $12.00$879K - Jan 21, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct41.6K shares at avg. $0.62$26K - Jan 21, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct15.8K shares at avg. $0.05$791.7 - Jan 21, 2026AMPX
Amprius Technologies, Inc.
Exercise(M)Direct15.9K shares at avg. $0.05$794.15 - Dec 11, 2025AMPX
Amprius Technologies, Inc.
Sale(S)Direct198.3K shares at avg. $10.51$2.1M - Dec 11, 2025AMPX
Amprius Technologies, Inc.
Exercise(M)Direct125K shares at avg. $0.05$6K - Nov 21, 2025AMPX
Amprius Technologies, Inc.
Sale(S)Direct25K shares at avg. $10.08$252K - Aug 21, 2025AMPX
Amprius Technologies, Inc.
Sale(S)Direct19.2K shares at avg. $6.82$131K - May 21, 2025AMPX
Amprius Technologies, Inc.
Sale(S)Direct20.4K shares at avg. $2.43$50K - Mar 19, 2025AMPX
Amprius Technologies, Inc.
Award(A)Direct461.5K shares- - Mar 14, 2025AMPX
Amprius Technologies, Inc.
Exercise(M)Direct3.5K shares at avg. $0.98$3K
| Type | Shares | Price | Ownership | |||
|---|---|---|---|---|---|---|
| Aug 21, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 29,681 | $10.34 | $306,931 | Direct |
| May 27, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 3,208 | $17.19 | $55,157 | Direct |
| May 21, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 28,812 | $14.79 | $426,083 | Direct |
| Mar 4, 2026 | AMPX Amprius Technologies, Inc. | Award(A) | 110,000 | - | $0 | Direct |
| Feb 23, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 25,366 | $10.16 | $257,604 | Direct |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 39,600 | $0.05 | $1,980 | Direct |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 90 | $0.62 | $56 | Direct |
| Jan 28, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 39,690 | $12.00 | $476,351 | Direct |
| Jan 23, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 1,600 | $0.05 | $80 | Direct |
| Jan 23, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 1,600 | $12.00 | $19,200 | Direct |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 166,104 | $0.05 | $8,305 | Direct |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 492,827 | $12.04 | $5,931,912 | Direct |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 253,928 | $0.05 | $12,696 | Direct |
| Jan 22, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 72,795 | $0.45 | $32,758 | Direct |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | Sale(S) | 73,280 | $12.00 | $879,411 | Direct |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 41,563 | $0.62 | $25,769 | Direct |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 15,834 | $0.05 | $792 | Direct |
| Jan 21, 2026 | AMPX Amprius Technologies, Inc. | Exercise(M) | 15,883 | $0.05 | $794 | Direct |
| Dec 11, 2025 | AMPX Amprius Technologies, Inc. | Sale(S) | 198,255 | $10.51 | $2,083,382 | Direct |
| Dec 11, 2025 | AMPX Amprius Technologies, Inc. | Exercise(M) | 125,000 | $0.05 | $6,250 | Direct |
| Nov 21, 2025 | AMPX Amprius Technologies, Inc. | Sale(S) | 25,024 | $10.08 | $252,274 | Direct |
| Aug 21, 2025 | AMPX Amprius Technologies, Inc. | Sale(S) | 19,159 | $6.82 | $130,592 | Direct |
| May 21, 2025 | AMPX Amprius Technologies, Inc. | Sale(S) | 20,366 | $2.43 | $49,530 | Direct |
| Mar 19, 2025 | AMPX Amprius Technologies, Inc. | Award(A) | 461,540 | - | - | Direct |
| Mar 14, 2025 | AMPX Amprius Technologies, Inc. | Exercise(M) | 3,471 | $0.98 | $3,402 | Direct |
1-25 of 30 transactions
About Stefan Constantin Ionel
Stefan Constantin Ionel (SEC CIK 0001940928) files insider reports with the SEC as Chief Technology Officer of Amprius Technologies, Inc. (AMPX).
Signal8 holds 16 ownership filings by Stefan Constantin Ionel, all Form 4s, filed between Oct 25, 2024 and Aug 25, 2026. Those filings report 30 transactions, from Oct 23, 2024 to Aug 21, 2026. Signal8's Form 4 history starts in Sep 2024.
The business address on Stefan Constantin Ionel's filings is in FREMONT, CA.
Recent filings by Stefan Constantin Ionel
- Aug 21, 2026: Open-market sale of AMPX shares (Form 4, code S).
- May 27, 2026: Open-market sale of AMPX shares (Form 4, code S).
- May 21, 2026: Open-market sale of AMPX shares (Form 4, code S).
- Mar 4, 2026: Grant or award of AMPX shares (Form 4, code A).
- Feb 23, 2026: Open-market sale of AMPX shares (Form 4, code S).
Other insiders filing for Amprius Technologies, Inc. (AMPX)
- Sun Kang, Director
- Stepien Thomas M, Chief Executive Officer
- BAYLESS KATHLEEN A, Director
- SATTERTHWAITE LIVINGSTON, Director
- DIXON DONALD R, Director
- Chu Steven, Director