Amprius Technologies, Inc. (AMPX) · Insider trading

What Amprius Technologies's directors, officers and largest holders bought and sold themselves, from the Form 4 each of them files with the SEC within two business days of a trade. Open-market purchases and sales first: those are the trades somebody chose to make at the market price.

Bought, 12 months

0 insiders, 0 trades

Sold, 12 months

$85.69M

6 insiders, 0% under a plan

Net, 12 months

−$85.69M

bought less sold

Latest filing

2026-08-25

filings read to 2026-10-19

Bought and sold at the market, by month

Two years. Purchases above the line, sales below, in dollars.

Bought Sold Largest month: $23.86M

Who traded, two years

Insider	Bought	Sold	Trades	Last trade	Holds after
Sun KangDirector	–	$58.42M	17	2026-08-21	1,218,397
Stefan Constantin IonelChief Technology Officer	–	$10.92M	14	2026-08-21	771,629
Hsieh Wen HsuanDirector	–	$7.62M	2	2026-03-12	175,090
Chu StevenDirector	–	$5.86M	4	2026-03-12	182,904
Dixon Donald RDirector	–	$2.54M	3	2026-06-15	–
Stepien Thomas MDirector, Chief Executive Officer	–	$1.34M	5	2026-08-24	594,096
Bornstein JonathanPresident of Amprius Lab	–	$363,742	4	2025-02-21	419,197
Wallach SandraChief Financial Officer	–	$351,090	4	2025-08-21	1,005,275

Open-market purchases and sales

Newest first. “Plan” marks a trade made under a 10b5-1 plan set up in advance.

Date	Insider	Trade	Shares	Price	Value	Holds after	Filing
2026-08-24	Stepien Thomas MDirector, Chief Executive Officer	Sale	8,000	10.03	$80,240	594,096	Form 4
2026-08-21	Sun KangDirector	Sale	62,101	10.34	$642,124	1,218,397	Form 4
2026-08-21	Stefan Constantin IonelChief Technology Officer	Sale	29,681	10.34	$306,902	771,629	Form 4
2026-08-21	Stepien Thomas MDirector, Chief Executive Officer	Sale	23,529	10.34	$243,290	602,096	Form 4
2026-06-15	Dixon Donald RDirector	Saleindirect	85,000	17.17	$1.46M	359,380	Form 4
2026-06-09	Dixon Donald RDirector	Saleindirect	40,000	19.13	$765,200	444,380	Form 4
2026-06-04	Stepien Thomas MDirector, Chief Executive Officer	Sale	2,000	20.97	$41,940	625,625	Form 4
2026-05-27	Sun KangDirector	Sale	356	17.19	$6,120	1,280,498	Form 4
2026-05-27	Stefan Constantin IonelChief Technology Officer	Sale	3,208	17.19	$55,146	801,310	Form 4
2026-05-27	Stepien Thomas MDirector, Chief Executive Officer	Sale	4,375	17.19	$75,206	694,923	Form 4
2026-05-26	Dixon Donald RDirector	Saleindirect	17,895	17.90	$320,320	484,380	Form 4
2026-05-21	Sun KangDirector	Sale	67,796	14.79	$1.00M	1,280,854	Form 4
2026-05-21	Stefan Constantin IonelChief Technology Officer	Sale	28,812	14.79	$426,129	804,518	Form 4
2026-05-21	Stepien Thomas MDirector, Chief Executive Officer	Sale	60,702	14.79	$897,783	699,298	Form 4
2026-04-01	Sun KangDirector	Sale	1,250,963	15.73	$19.68M	1,591,437	Form 4
2026-04-01	Sun KangDirector	Sale	249,037	16.78	$4.18M	1,342,400	Form 4
2026-03-23	Sun KangDirector	Saleindirect	152,823	18.69	$2.86M	121,452	Form 4
2026-03-23	Sun KangDirector	Saleindirect	65,046	19.06	$1.24M	56,406	Form 4
2026-03-12	Hsieh Wen HsuanDirector	Sale	282,500	18.55	$5.24M	175,090	Form 4
2026-03-12	Hsieh Wen HsuanDirector	Sale	130,646	18.22	$2.38M	44,444	Form 4
2026-03-12	Chu StevenDirector	Sale	100,000	18.65	$1.86M	182,904	Form 4
2026-03-12	Chu StevenDirector	Sale	50,000	18.21	$910,500	132,904	Form 4
2026-03-12	Chu StevenDirector	Sale	5,565	18.53	$103,119	127,339	Form 4
2026-03-10	Chu StevenDirector	Sale	166,632	17.92	$2.99M	127,339	Form 4
2026-02-23	Sun KangDirector	Sale	61,251	10.16	$622,310	1,342,400	Form 4
2026-02-23	Stefan Constantin IonelChief Technology Officer	Sale	25,366	10.16	$257,719	723,330	Form 4
2026-01-28	Stefan Constantin IonelChief Technology Officer	Sale	39,690	12.00	$476,280	748,696	Form 4
2026-01-23	Stefan Constantin IonelChief Technology Officer	Sale	1,600	12.00	$19,200	748,696	Form 4
2026-01-22	Stefan Constantin IonelChief Technology Officer	Sale	492,827	12.04	$5.93M	748,696	Form 4
2026-01-21	Stefan Constantin IonelChief Technology Officer	Sale	73,280	12.00	$879,360	748,696	Form 4
2026-01-20	Sun KangDirector	Sale	43,185	11.03	$476,331	1,403,651	Form 4
2026-01-16	Sun KangDirector	Sale	950,548	11.07	$10.52M	1,403,651	Form 4
2026-01-12	Sun KangDirector	Sale	506,267	10.10	$5.11M	1,403,651	Form 4
2025-12-11	Stefan Constantin IonelChief Technology Officer	Sale	198,255	10.51	$2.08M	748,696	Form 4
2025-11-21	Sun KangDirector, Chief Executive Officer	Sale	68,655	10.08	$692,042	1,403,651	Form 4
2025-11-21	Stefan Constantin IonelChief Technology Officer	Sale	25,024	10.08	$252,242	821,951	Form 4
2025-11-17	Sun KangDirector, Chief Executive Officer	Sale	1,000,000	10.60	$10.60M	1,472,306	Form 4
2025-08-21	Sun KangDirector, Chief Executive Officer	Sale	65,654	6.82	$447,760	1,472,306	Form 4
2025-08-21	Wallach SandraChief Financial Officer	Sale	28,390	6.82	$193,620	1,005,275	Form 4
2025-08-21	Stefan Constantin IonelChief Technology Officer	Sale	19,159	6.82	$130,664	846,975	Form 4

13 more

2025-05-21	Sun KangDirector, Chief Executive Officer	Sale	69,786	2.43	$169,580	1,812,235	Form 4
2025-05-21	Wallach SandraChief Financial Officer	Sale	27,595	2.43	$67,056	1,033,665	Form 4
2025-05-21	Stefan Constantin IonelChief Technology Officer	Sale	20,366	2.43	$49,489	866,134	Form 4
2025-02-21	Sun KangDirector, Chief Executive Officer	Sale	34,353	3.13	$107,525	1,282,621	Form 4
2025-02-21	Wallach SandraChief Financial Officer	Sale	18,142	3.13	$56,784	678,000	Form 4
2025-02-21	Stefan Constantin IonelChief Technology Officer	Sale	9,066	3.13	$28,377	421,489	Form 4
2025-02-21	Bornstein JonathanPresident of Amprius Lab	Sale	13,527	3.13	$42,340	419,197	Form 4
2024-11-21	Sun KangDirector, Chief Executive Officer	Sale	33,779	1.96	$66,207	1,316,974	Form 4
2024-11-21	Wallach SandraChief Financial Officer	Sale	17,158	1.96	$33,630	696,142	Form 4
2024-11-21	Stefan Constantin IonelChief Technology Officer	Sale	8,575	1.96	$16,807	430,555	Form 4
2024-11-21	Bornstein JonathanPresident of Amprius Lab	Saleindirect	15,000	1.96	$29,400	1,040,950	Form 4
2024-11-21	Bornstein JonathanPresident of Amprius Lab	Sale	18,170	1.96	$35,613	454,131	Form 4
2024-11-20	Bornstein JonathanPresident of Amprius Lab	Saleindirect	133,536	1.92	$256,389	1,039,187	Form 4

Grants, exercises and other transactions

Pay, tax and paperwork rather than a choice to trade at the market price. Two years.

28 × option exercise20 × grant or award7 × gift2 × other

Show them

Date	Insider	What	Shares	Price	Holds after	Filing
2026-08-25	Stepien Thomas MDirector, Chief Executive Officer	Gift G	−5,000	–	589,096	Form 4
2026-08-25	Stepien Thomas MDirector, Chief Executive Officer	Gift G	−5,000	–	584,096	Form 4
2026-08-25	Stepien Thomas MDirector, Chief Executive Officer	Gift G	−5,000	–	579,096	Form 4
2026-08-25	Stepien Thomas MDirector, Chief Executive Officer	Gift G	−346	–	578,750	Form 4
2026-08-25	Stepien Thomas MDirector, Chief Executive Officer	Grant or award A	+346	–	37,260	Form 4
2026-06-12	Dixon Donald RDirector	Grant or award A	+10,423	–	280,079	Form 4
2026-06-12	Bayless Kathleen ADirector	Grant or award A	+10,423	–	216,120	Form 4
2026-06-12	Chu StevenDirector	Grant or award A	+10,423	–	137,762	Form 4
2026-06-12	Satterthwaite LivingstonDirector	Grant or award A	+10,423	–	346,506	Form 4
2026-06-04	Stepien Thomas MDirector, Chief Executive Officer	Gift G	−30,384	–	664,539	Form 4
2026-06-04	Stepien Thomas MDirector, Chief Executive Officer	Gift G	−36,914	–	627,625	Form 4
2026-06-04	Stepien Thomas MDirector, Chief Executive Officer	Gift G	+36,914	–	36,914	Form 4
2026-05-05	Sun KangDirector	Grant or award A	+6,250	–	1,348,650	Form 4
2026-04-01	Sun KangDirector	Option exercise M	+1,312,505	1.78	2,654,905	Form 4
2026-04-01	Sun KangDirector	Option exercise M	+187,495	3.68	2,842,400	Form 4
2026-03-12	Hsieh Wen HsuanDirector	Option exercise M	+270,251	2.61	457,590	Form 4
2026-03-12	Chu StevenDirector	Option exercise M	+86,143	2.61	213,482	Form 4
2026-03-12	Chu StevenDirector	Option exercise M	+69,422	0.62	282,904	Form 4
2026-03-10	Chu StevenDirector	Option exercise M	+104,132	0.62	293,971	Form 4
2026-03-04	Rodriguez Ricardo C.Chief Financial Officer	Grant or award A	+150,000	–	350,000	Form 4/A
2026-03-04	Stefan Constantin IonelChief Technology Officer	Grant or award A	+110,000	–	833,330	Form 4
2026-03-04	Stepien Thomas MDirector, Chief Executive Officer	Grant or award A	+150,000	–	760,000	Form 4
2026-01-28	Stefan Constantin IonelChief Technology Officer	Option exercise M	+90	0.62	748,786	Form 4
2026-01-28	Stefan Constantin IonelChief Technology Officer	Option exercise M	+39,600	0.05	788,386	Form 4
2026-01-23	Stefan Constantin IonelChief Technology Officer	Option exercise M	+1,600	0.05	750,296	Form 4
2026-01-22	Stefan Constantin IonelChief Technology Officer	Option exercise M	+253,928	0.05	1,002,624	Form 4
2026-01-22	Stefan Constantin IonelChief Technology Officer	Option exercise M	+72,795	0.45	1,075,419	Form 4
2026-01-22	Stefan Constantin IonelChief Technology Officer	Option exercise M	+166,104	0.05	1,241,523	Form 4
2026-01-21	Stefan Constantin IonelChief Technology Officer	Option exercise M	+41,563	0.62	790,259	Form 4
2026-01-21	Stefan Constantin IonelChief Technology Officer	Option exercise M	+15,834	0.05	806,093	Form 4
2026-01-21	Stefan Constantin IonelChief Technology Officer	Option exercise M	+15,883	0.05	821,976	Form 4
2026-01-20	Sun KangDirector	Option exercise M	+43,185	1.78	1,446,836	Form 4
2026-01-16	Sun KangDirector	Option exercise M	+850,338	2.50	2,253,989	Form 4
2026-01-16	Sun KangDirector	Option exercise M	+100,210	1.78	2,354,199	Form 4
2026-01-12	Sun KangDirector	Option exercise M	+180,802	0.62	1,584,453	Form 4
2026-01-12	Sun KangDirector	Option exercise M	+208,264	2.44	1,792,717	Form 4
2026-01-12	Sun KangDirector	Option exercise M	+117,201	2.50	1,909,918	Form 4
2025-12-19	Stepien Thomas MDirector, Chief Executive Officer	Grant or award A	+200,000	–	760,000	Form 4/A
2025-12-11	Stefan Constantin IonelChief Technology Officer	Option exercise M	+125,000	0.05	946,951	Form 4
2025-11-17	Sun KangDirector, Chief Executive Officer	Option exercise M	+202,934	0.98	1,675,240	Form 4
2025-11-17	Sun KangDirector, Chief Executive Officer	Option exercise M	+727,950	0.05	2,403,190	Form 4
2025-11-17	Sun KangDirector, Chief Executive Officer	Option exercise M	+27,463	0.62	2,430,653	Form 4
2025-11-17	Sun KangDirector, Chief Executive Officer	Option exercise M	+41,653	0.62	2,472,306	Form 4
2025-10-06	Rodriguez Ricardo C.Chief Financial Officer	Grant or award A	+200,000	–	200,000	Form 4
2025-06-13	Chu StevenDirector	Grant or award A	+44,444	–	189,839	Form 4
2025-06-13	Bayless Kathleen ADirector	Grant or award A	+44,444	–	205,697	Form 4
2025-06-13	Satterthwaite LivingstonDirector	Grant or award A	+44,444	–	336,083	Form 4
2025-06-13	Dixon Donald RDirector	Grant or award A	+44,444	–	394,656	Form 4
2025-06-13	Hsieh Wen HsuanDirector	Grant or award A	+44,444	–	187,339	Form 4
2025-05-01	Stepien Thomas MDirector, President	Grant or award A	+400,000	–	400,000	Form 4
2025-03-19	Sun KangDirector, Chief Executive Officer	Grant or award A	+599,400	–	1,882,021	Form 4
2025-03-19	Wallach SandraChief Financial Officer	Grant or award A	+383,260	–	1,061,260	Form 4
2025-03-19	Stefan Constantin IonelChief Technology Officer	Grant or award A	+461,540	–	886,500	Form 4
2025-03-14	Stefan Constantin IonelChief Technology Officer	Option exercise M	+3,471	0.98	424,960	Form 4
2025-03-10	Bornstein JonathanPresident of Amprius Lab	Option exercise M	+3,471	0.98	422,668	Form 4
2024-10-23	Amprius, Inc.10% owner	Other J	−5,500,000	–	59,695,997	Form 4
2024-10-23	Amprius, Inc.10% owner	Other J	−57,195,926	–	2,500,071	Form 4

How to read it

Buy, sale: Code P and S on the form: shares bought or sold in the market, at the market price. The other codes are mostly pay (a grant, an option exercised) or tax (shares the company withheld), and say little about what the insider thinks of the price.
Plan: A sale or purchase under a Rule 10b5-1 plan, set up in advance and running on its own schedule. Since April 2023 the form has a box for it. Much executive selling is planned and says more about diversifying than about the company.
Holds after: The shares the insider still held after the trade, in the form the trade was in (directly, or indirectly through a trust or a fund).
Value: Shares times the price the form reports, which is often an average over several fills on the day.

Read from the SEC's own quarterly data sets of Forms 3, 4 and 5, and from each day's filings since the last one. A correcting amendment replaces the lines it restates. Every row links to its filing. None of this is advice: insiders sell for many reasons, and buy for fewer.

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