Stefan Constantin Ionel

Officer · AMPX

As of 2026-09-16, Stefan Constantin Ionel has 37 Form 4 transactions on record across 1 company — 31 in the trailing 12 months.

Everything this person has disclosed to the SEC on Form 4 — across every company they file for — reconstructed from the public record. A filing history, not a tip sheet.

Pattern in the record: open-market sales filed in August in multiple years since 2025 — a recurring calendar cadence, more consistent with scheduled activity than a one-off decision.

Reconstructed holdings

Direct: $7.0MIndirect: $0$7.0Mas of 2026-09-16
  • Direct $7.0M
  • Indirect $0
AMPXdirect771,629 sh$7.0M

Reconstructed from this person's own Form 4 filings — the total each filing reported owning afterward, priced at the close on the as-of date shown. A filed position can lag the real one.

Direct and indirect holdings (e.g. through a trust or fund) are tagged separately, as filed.

Trades by company

AMPX · 37 trades
2026-08-21: Sale, 29,681 sh ($307K)2026-05-27: Sale, 3,208 sh ($55K)2026-05-21: Sale, 28,812 sh ($426K)2026-03-04: Award / grant, 110,000 sh ($0)2026-02-23: Sale, 25,366 sh ($258K)2026-01-28: Sale, 39,690 sh ($476K)2026-01-28: Option exercise, 39,600 sh ($2K)2026-01-28: Option exercise, 90 sh ($56)2026-01-28: Option exercise, 90 sh ($0)2026-01-28: Option exercise, 39,600 sh ($0)2026-01-23: Sale, 1,600 sh ($19K)2026-01-23: Option exercise, 1,600 sh ($80)2026-01-23: Option exercise, 1,600 sh ($0)2026-01-22: Sale, 492,827 sh ($5.9M)2026-01-22: Option exercise, 72,795 sh ($33K)2026-01-22: Option exercise, 253,928 sh ($13K)2026-01-22: Option exercise, 166,104 sh ($8K)2026-01-22: Option exercise, 166,104 sh ($0)2026-01-22: Option exercise, 253,928 sh ($0)2026-01-22: Option exercise, 72,795 sh ($0)2026-01-21: Sale, 73,280 sh ($879K)2026-01-21: Option exercise, 41,563 sh ($26K)2026-01-21: Option exercise, 15,883 sh ($794)2026-01-21: Option exercise, 15,834 sh ($792)2026-01-21: Option exercise, 41,563 sh ($0)2026-01-21: Option exercise, 15,834 sh ($0)2026-01-21: Option exercise, 15,883 sh ($0)2025-12-11: Sale, 198,255 sh ($2.1M)2025-12-11: Option exercise, 125,000 sh ($6K)2025-12-11: Option exercise, 125,000 sh ($0)2025-11-21: Sale, 25,024 sh ($252K)2025-08-21: Sale, 19,159 sh ($131K)2025-05-21: Sale, 20,366 sh ($50K)2025-03-19: Award / grant, 461,540 sh ($0)2025-03-14: Option exercise, 3,471 sh ($3K)2025-03-14: Option exercise, 3,471 sh ($0)2025-02-21: Sale, 9,066 sh ($28K)

Filing ledger

DateCompanyActionShares @ priceValueOwnership ΔOwned afterFiling
2026-08-21AMPXSale29,681 @ $10.34$307K−3.7% of holding771,629Form 4
2026-05-27AMPXSale3,208 @ $17.19$55K−0.4% of holding801,310Form 4
2026-05-21AMPXSale28,812 @ $14.79$426K−3.5% of holding804,518Form 4
2026-02-23AMPXSale25,366 @ $10.16$258K−3.4% of holding723,330Form 4
2026-01-28AMPXSale39,690 @ $12.00$476K−5.0% of holding748,696Form 4
2026-01-23AMPXSale1,600 @ $12.00$19K−0.2% of holding748,696Form 4
2026-01-22AMPXSale492,827 @ $12.04$5.9M−39.7% of holding748,696Form 4
2026-01-21AMPXSale73,280 @ $12.00$879K−8.9% of holding748,696Form 4
2025-12-11AMPXSale198,255 @ $10.51$2.1M−20.9% of holding748,696Form 4
2025-11-21AMPXSale25,024 @ $10.08$252K−3.0% of holding821,951Form 4
2025-08-21AMPXSale19,159 @ $6.82$131K−2.2% of holding846,975Form 4
2025-05-21AMPXSale20,366 @ $2.43$50K−2.3% of holding866,134Form 4
2025-02-21AMPXSale9,066 @ $3.13$28K−2.1% of holding421,489Form 4
24 award / exercise / gift records — not counted as purchases
DateCompanyActionSharesOwned afterFiling
2026-03-04AMPXAward / grant110,000833,330Form 4
2026-01-28AMPXOption exercise39,600788,386Form 4
2026-01-28AMPXOption exercise90748,786Form 4
2026-01-28AMPXOption exercise900Form 4
2026-01-28AMPXOption exercise39,6000Form 4
2026-01-23AMPXOption exercise1,600750,296Form 4
2026-01-23AMPXOption exercise1,60039,600Form 4
2026-01-22AMPXOption exercise72,7951,075,419Form 4
2026-01-22AMPXOption exercise253,9281,002,624Form 4
2026-01-22AMPXOption exercise166,1041,241,523Form 4
2026-01-22AMPXOption exercise166,1040Form 4
2026-01-22AMPXOption exercise253,92841,200Form 4
2026-01-22AMPXOption exercise72,7950Form 4
2026-01-21AMPXOption exercise41,563790,259Form 4
2026-01-21AMPXOption exercise15,883821,976Form 4
2026-01-21AMPXOption exercise15,834806,093Form 4
2026-01-21AMPXOption exercise41,56390Form 4
2026-01-21AMPXOption exercise15,834295,128Form 4
2026-01-21AMPXOption exercise15,883166,104Form 4
2025-12-11AMPXOption exercise125,000946,951Form 4
2025-12-11AMPXOption exercise125,000310,962Form 4
2025-03-19AMPXAward / grant461,540886,500Form 4
2025-03-14AMPXOption exercise3,471424,960Form 4
2025-03-14AMPXOption exercise3,4710Form 4

Source: SEC Form 4 filings. Each row links to its original filing.

Research tool, not investment advice — historical frequencies, not recommendations. A product of Marovel Technologies LLC. Full terms.