Company · Ownership research

Amprius Technologies, Inc. AMPX

CIK 0001899287

Form 4 transactions dated Sep 1, 2023 to Sep 26, 2026, as reported to the SEC.

Insider trading Initial holdings Institutional holders

Insider filings on file run through 2026-08-25.

Insider purchases & sales

Purchased: $0.00
Sold: $97.47M

Sep 1, 2023 – Aug 25, 2026
Available records · partial months are marked ·

202510 of 14 preview events

Date	Insider	Activity	Trade value (USD)	% of prior holding
2025-12-11	Stefan Constantin Ionel Chief Technology Officer	Sale10b5-1 footnote	$2.08M 198,255 shares sold	20.94% sold Direct holding	▾
2025-11-21	Stefan Constantin Ionel Chief Technology Officer	Sale	$252.27K 25,024 shares sold	2.95% sold Direct holding	▾
2025-11-21	Sun Kang Chief Executive Officer · Director	Sale	$692.13K 68,655 shares sold	4.66% sold Direct holding	▾
2025-11-17	Sun Kang Chief Executive Officer · Director	Sale10b5-1 footnote	$10.60M 1,000,000 shares sold	40.45% sold Direct holding	▾
2025-08-21	Stefan Constantin Ionel Chief Technology Officer	Sale	$130.59K 19,159 shares sold	2.21% sold Direct holding	▾
2025-08-21	Wallach Sandra Chief Financial Officer	Sale	$193.51K 28,390 shares sold	2.75% sold Direct holding	▾
2025-08-21	Sun Kang Chief Executive Officer · Director	Sale	$447.51K 65,654 shares sold	4.27% sold Direct holding	▾
2025-05-21	Stefan Constantin Ionel Chief Technology Officer	Sale	$49.53K 20,366 shares sold	2.30% sold Direct holding	▾
2025-05-21	Wallach Sandra Chief Financial Officer	Sale	$67.11K 27,595 shares sold	2.60% sold Direct holding	▾
2025-05-21	Sun Kang Chief Executive Officer · Director	Sale	$169.72K 69,786 shares sold	3.71% sold Direct holding	▾

Showing 14 / 14 record groups in 2025. The complete set is available through the API.

Amprius Technologies, Inc. · AMPX

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The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. For the year shown, this page lists 14 of 14 purchase / sale groups and 22 of 22 other groups; the totals and the monthly series cover the whole window.

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{"ticker":"AMPX","transaction_code":["P","S"],"transaction_form_type":"4","page_size":20}

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Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.

Non-cancelled, non-derivative purchase (P) and sale (S) rows dated inside the public window, as reported. Includes open-market and private transactions. Data after the latest filing is not asserted complete and is not zero-filled. A grouped event shares filing, transaction date, security, code, direction, ownership bucket and source. Derivative groups also match underlying security, exercise price, exercise/expiration dates and footnote references. Reported rows are retained; P/S price lots can be grouped. Post-transaction balances are never summed.