Follow the people · Insider
Constantin Ionel Stefan
Constantin Ionel Stefan files insider transactions with the SEC as a chief technology officer of Amprius Technologies (AMPX). We hold 8 disclosed purchases and sales filed since 16 September 2022, 1 of them in the last 90 days.
- Files forAMPX
- Disclosed buys and sells8 in all, 1 in the last 90 days
- Last disclosure25 August 2026
Positions held
1 post we hold — a term names its own dates; a run of filings only says when they filed- Filed 14 September 2022 — 21 August 2026Chief Technology Officer · Amprius Technologies (AMPX)81 Form 4 lines · source: SEC Form 4
Everything they disclosed
81 entries, newest first — one per disclosure report, one per Form 4 line- ▼ sold on the open market 29,681 shares of Amprius TechnologiesSEC Form 425 August 2026Common stock · traded 21 August 2026 · filed 25 August 2026
- ▼ sold on the open market 3,208 shares of Amprius TechnologiesSEC Form 428 May 2026Common stock · traded 27 May 2026 · filed 28 May 2026
- ▼ sold on the open market 28,812 shares of Amprius TechnologiesSEC Form 426 May 2026Common stock · traded 21 May 2026 · filed 26 May 2026
- was granted 110,000 shares of Amprius TechnologiesSEC Form 46 March 2026Common stock · traded 4 March 2026 · filed 6 March 2026
- was granted 110,000 shares of Amprius TechnologiesSEC Form 46 March 2026Common stock · traded 4 March 2026 · filed 6 March 2026
- ▼ sold on the open market 25,366 shares of Amprius TechnologiesSEC Form 424 February 2026Common stock · traded 23 February 2026 · filed 24 February 2026
- ▼ sold on the open market 25,366 shares of Amprius TechnologiesSEC Form 424 February 2026Common stock · traded 23 February 2026 · filed 24 February 2026
- exercised options over 90 shares of Amprius TechnologiesSEC Form 430 January 2026Common stock · traded 28 January 2026 · filed 30 January 2026
- exercised options over 39,600 shares of Amprius TechnologiesSEC Form 430 January 2026Common stock · traded 28 January 2026 · filed 30 January 2026
- ▼ sold on the open market 39,690 shares of Amprius TechnologiesSEC Form 430 January 2026Common stock · traded 28 January 2026 · filed 30 January 2026
- exercised options over 90 shares of Amprius Technologies (a derivative holding)SEC Form 430 January 2026Stock Option (right to buy) · traded 28 January 2026 · filed 30 January 2026
- exercised options over 39,600 shares of Amprius Technologies (a derivative holding)SEC Form 430 January 2026Stock Option (right to buy) · traded 28 January 2026 · filed 30 January 2026
- exercised options over 90 shares of Amprius Technologies (a derivative holding)SEC Form 430 January 2026Stock Option (right to buy) · traded 28 January 2026 · filed 30 January 2026
- exercised options over 39,600 shares of Amprius Technologies (a derivative holding)SEC Form 430 January 2026Stock Option (right to buy) · traded 28 January 2026 · filed 30 January 2026
- exercised options over 90 shares of Amprius TechnologiesSEC Form 430 January 2026Common stock · traded 28 January 2026 · filed 30 January 2026
- exercised options over 39,600 shares of Amprius TechnologiesSEC Form 430 January 2026Common stock · traded 28 January 2026 · filed 30 January 2026
- ▼ sold on the open market 39,690 shares of Amprius TechnologiesSEC Form 430 January 2026Common stock · traded 28 January 2026 · filed 30 January 2026
- exercised options over 41,563 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- ▼ sold on the open market 1,600 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 23 January 2026 · filed 23 January 2026
- exercised options over 41,563 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,834 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,883 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 21 January 2026 · filed 23 January 2026
- exercised options over 253,928 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 22 January 2026 · filed 23 January 2026
- exercised options over 72,795 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 22 January 2026 · filed 23 January 2026
- exercised options over 166,104 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 22 January 2026 · filed 23 January 2026
- exercised options over 1,600 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 23 January 2026 · filed 23 January 2026
- exercised options over 15,834 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,883 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- exercised options over 41,563 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,834 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,883 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 21 January 2026 · filed 23 January 2026
- exercised options over 253,928 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 22 January 2026 · filed 23 January 2026
- exercised options over 72,795 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 22 January 2026 · filed 23 January 2026
- exercised options over 166,104 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 22 January 2026 · filed 23 January 2026
- exercised options over 1,600 shares of Amprius Technologies (a derivative holding)SEC Form 423 January 2026Stock Option (right to buy) · traded 23 January 2026 · filed 23 January 2026
- ▼ sold on the open market 73,280 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- exercised options over 253,928 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- exercised options over 72,795 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- exercised options over 166,104 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- ▼ sold on the open market 492,827 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- exercised options over 41,563 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,834 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- exercised options over 15,883 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- ▼ sold on the open market 73,280 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 21 January 2026 · filed 23 January 2026
- exercised options over 253,928 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- exercised options over 72,795 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- exercised options over 166,104 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- ▼ sold on the open market 492,827 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 22 January 2026 · filed 23 January 2026
- exercised options over 1,600 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 23 January 2026 · filed 23 January 2026
- ▼ sold on the open market 1,600 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 23 January 2026 · filed 23 January 2026
- exercised options over 1,600 shares of Amprius TechnologiesSEC Form 423 January 2026Common stock · traded 23 January 2026 · filed 23 January 2026
- exercised options over 125,000 shares of Amprius Technologies (a derivative holding)SEC Form 415 December 2025Stock Option (right to buy) · traded 11 December 2025 · filed 15 December 2025
- exercised options over 125,000 shares of Amprius TechnologiesSEC Form 415 December 2025Common stock · traded 11 December 2025 · filed 15 December 2025
- ▼ sold on the open market 198,255 shares of Amprius TechnologiesSEC Form 415 December 2025Common stock · traded 11 December 2025 · filed 15 December 2025
- ▼ sold on the open market 25,024 shares of Amprius TechnologiesSEC Form 425 November 2025Common stock · traded 21 November 2025 · filed 25 November 2025
- ▼ sold on the open market 19,159 shares of Amprius TechnologiesSEC Form 425 August 2025Common stock · traded 21 August 2025 · filed 25 August 2025
- ▼ sold on the open market 20,366 shares of Amprius TechnologiesSEC Form 423 May 2025Common stock · traded 21 May 2025 · filed 23 May 2025
- was granted 461,540 shares of Amprius TechnologiesSEC Form 421 March 2025Common stock · traded 19 March 2025 · filed 21 March 2025
- exercised options over 3,471 shares of Amprius Technologies (a derivative holding)SEC Form 418 March 2025Stock Option (right to buy) · traded 14 March 2025 · filed 18 March 2025
- exercised options over 3,471 shares of Amprius TechnologiesSEC Form 418 March 2025Common stock · traded 14 March 2025 · filed 18 March 2025
- ▼ sold on the open market 9,066 shares of Amprius TechnologiesSEC Form 424 February 2025Common stock · traded 21 February 2025 · filed 24 February 2025
- ▼ sold on the open market 8,575 shares of Amprius TechnologiesSEC Form 422 November 2024Common stock · traded 21 November 2024 · filed 22 November 2024
- was granted 3,471 shares of Amprius Technologies (a derivative holding)SEC Form 425 October 2024Stock Option (right to buy) · traded 23 October 2024 · filed 25 October 2024
- was granted 41,653 shares of Amprius Technologies (a derivative holding)SEC Form 425 October 2024Stock Option (right to buy) · traded 23 October 2024 · filed 25 October 2024
- was granted 139,613 shares of Amprius Technologies (a derivative holding)SEC Form 425 October 2024Stock Option (right to buy) · traded 23 October 2024 · filed 25 October 2024
- ▼ sold on the open market 8,800 shares of Amprius TechnologiesSEC Form 422 August 2024Common stock · traded 21 August 2024 · filed 22 August 2024
- ▼ sold on the open market 5,272 shares of Amprius TechnologiesSEC Form 424 May 2024Common stock · traded 21 May 2024 · filed 24 May 2024
- ▼ sold on the open market 4,121 shares of Amprius TechnologiesSEC Form 424 May 2024Common stock · traded 22 May 2024 · filed 24 May 2024
- was granted 374,570 shares of Amprius TechnologiesSEC Form 419 March 2024Common stock · traded 19 March 2024 · filed 19 March 2024
- ▼ sold on the open market 46,370 shares of Amprius TechnologiesSEC Form 418 September 2023Common stock · traded 14 September 2023 · filed 18 September 2023
- ▼ sold on the open market 33,630 shares of Amprius TechnologiesSEC Form 418 September 2023Common stock · traded 15 September 2023 · filed 18 September 2023
- exercised options over 80,000 shares of Amprius Technologies (a derivative holding)SEC Form 412 September 2023Stock Option (right to buy) · traded 9 September 2023 · filed 12 September 2023
- exercised options over 80,000 shares of Amprius TechnologiesSEC Form 412 September 2023Common stock · traded 9 September 2023 · filed 12 September 2023
- had shares withheld for tax on 209 shares of Amprius TechnologiesSEC Form 43 May 2023Common stock · traded 14 December 2022 · filed 3 May 2023
- exercised options over 30,000 shares of Amprius Technologies (a derivative holding)SEC Form 415 December 2022Stock Option (right to buy) · traded 14 December 2022 · filed 15 December 2022
- exercised options over 30,000 shares of Amprius TechnologiesSEC Form 415 December 2022Common stock · traded 14 December 2022 · filed 15 December 2022
- was granted 545,962 shares of Amprius Technologies (a derivative holding)SEC Form 416 September 2022Stock Option (right to buy) · traded 14 September 2022 · filed 16 September 2022
- was granted 181,987 shares of Amprius Technologies (a derivative holding)SEC Form 416 September 2022Stock Option (right to buy) · traded 14 September 2022 · filed 16 September 2022
- was granted 72,795 shares of Amprius Technologies (a derivative holding)SEC Form 416 September 2022Stock Option (right to buy) · traded 14 September 2022 · filed 16 September 2022
- was granted 72,795 shares of Amprius Technologies (a derivative holding)SEC Form 416 September 2022Stock Option (right to buy) · traded 14 September 2022 · filed 16 September 2022
- was granted 218,385 shares of Amprius Technologies (a derivative holding)SEC Form 416 September 2022Stock Option (right to buy) · traded 14 September 2022 · filed 16 September 2022
Positions come from the unitedstates/congress-legislators roster, the Office of Government Ethics and the SEC’s Form 4 index. Every disclosed line names its own source and links the document the government published; we print what the filing says and never a price we did not read from it. Headlines and links come from the GDELT Global Knowledge Graph — the story stays with the publisher. The portrait, where we have one, is the public-domain Congressional Bioguide photograph.