13F Pro

SEC Form 4 reporting owner

Stefan Constantin Ionel

Stefan Constantin Ionel has filed 20 Form 4 transactions reported between November 21, 2025 and August 21, 2026, as Chief Technology Officer of Amprius Technologies, Inc..

Name as filed: Stefan Constantin Ionel

Open-market buys, 24 mo
None
reported
Open-market sales, 24 mo
$10.7M
9 lines
Companies
1
with Form 4 filings
Latest transaction
Aug 21, 2026
transaction date

Roles and reported holdings

  • AMPXAmprius Technologies, Inc.
    Nov 21, 2025 – Aug 21, 2026

    Chief Technology Officer

    Held directly771,629 sh as of Aug 21, 2026 · Form 4

    24 months: $10.7M sold

Transaction history

All 20 reported transactions, newest first. Every row links to the Form 4 on SEC EDGAR.

DateCompanyTypeSharesValueFiling
Aug 21, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct29,681$307K@ $10.34Form 4
May 27, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct3,208$55K@ $17.19Form 4
May 21, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct28,812$426K@ $14.79Form 4
Mar 4, 2026AMPXChief Technology OfficerGrant or awardCode A · direct110,000—Form 4
Feb 23, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct25,366$258K@ $10.16Form 4
Jan 28, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct39,690$476K@ $12.00Form 4
Jan 28, 2026AMPXChief Technology OfficerOption exerciseCode M · direct39,600$2K@ $0.0500Form 4
Jan 28, 2026AMPXChief Technology OfficerOption exerciseCode M · direct90$56@ $0.6200Form 4
Jan 23, 2026AMPXChief Technology OfficerOption exerciseCode M · direct1,600$80@ $0.0500Form 4
Jan 22, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct492,827$5.9M@ $12.04Form 4
Jan 22, 2026AMPXChief Technology OfficerOption exerciseCode M · direct166,104$8K@ $0.0500Form 4
Jan 22, 2026AMPXChief Technology OfficerOption exerciseCode M · direct72,795$33K@ $0.4500Form 4
Jan 22, 2026AMPXChief Technology OfficerOption exerciseCode M · direct253,928$13K@ $0.0500Form 4
Jan 21, 2026AMPXChief Technology OfficerOpen-market saleCode S · direct73,280$879K@ $12.00Form 4
Jan 21, 2026AMPXChief Technology OfficerOption exerciseCode M · direct15,883$794@ $0.0500Form 4
Jan 21, 2026AMPXChief Technology OfficerOption exerciseCode M · direct15,834$792@ $0.0500Form 4
Jan 21, 2026AMPXChief Technology OfficerOption exerciseCode M · direct41,563$26K@ $0.6200Form 4
Dec 11, 2025AMPXChief Technology OfficerOpen-market saleCode S · direct198,255$2.1M@ $10.51Form 4
Dec 11, 2025AMPXChief Technology OfficerOption exerciseCode M · direct125,000$6K@ $0.0500Form 4
Nov 21, 2025AMPXChief Technology OfficerOpen-market saleCode S · direct25,024$252K@ $10.08Form 4

How this page is built

Every row comes from a Form 4 filed with the SEC, which officers, directors and holders of more than 10% of a company’s stock must file within two business days of a trade. Transactions are grouped by the reporting owner’s name as filed (spacing, capitals and punctuation ignored); two different people filing under an identical name would appear together, and one person filing under two spellings appears on two pages.

Open-market totals count code P purchases and code S sales over the last 24 months. The same trade reported on more than one filing is counted once; when another owner (for example a fund and its general partner) reports the identical trade, they are listed beside it. Holdings are the shares owned after the latest purchase, sale, gift or tax-withholding line, shown separately for direct and indirect ownership; an indirect figure is one holding line, not a total across every trust or entity.

This page describes what was filed with the SEC; it is not investment advice or a recommendation to buy or sell any security.