Amprius insider Stepien plans sale of 8,000 shares

Amprius Technologies, Inc. (symbol AMPX) is named as the issuer in a notice filed by insider Thomas M. Stepien to sell company common stock under Rule 144.

Rhea-AI Filing Summary

Amprius Technologies, Inc. (symbol AMPX) is named as the issuer in a notice filed by insider Thomas M. Stepien to sell company common stock under Rule 144. The planned transaction involves 8,000 shares of common stock held at Morgan Stanley Smith Barney LLC, relating to restricted stock that vests on August 20, 2026 under a registered plan, with the issuer listed as Amprius and the consideration described as services rendered.

Over the prior three months, Thomas M. Stepien reported additional sales of Amprius common stock: 23,529 shares for $243,312.64 on August 20, 2026; 2,000 shares for $41,940.00 on June 4, 2026; and 4,375 shares for $75,221.56 on May 27, 2026.

Key Figures

Planned shares to be sold: 8,000 shares of common stock Recent sale on August 20, 2026: 23,529 shares for $243,312.64 Sale on June 4, 2026: 2,000 shares for $41,940.00 +2 more

5 metrics

Planned shares to be sold 8,000 shares of common stock Planned Rule 144 sale related to restricted stock vesting on August 20, 2026

Recent sale on August 20, 2026 23,529 shares for $243,312.64 Sale of Amprius common stock by Thomas M. Stepien

Sale on June 4, 2026 2,000 shares for $41,940.00 Sale of Amprius common stock by Thomas M. Stepien

Sale on May 27, 2026 4,375 shares for $75,221.56 Sale of Amprius common stock by Thomas M. Stepien

Vesting date of restricted stock August 20, 2026 Restricted stock vesting under a registered plan related to the 8,000 shares

Key Terms

Rule 144, Restricted Stock Vesting, Registered Plan

3 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Vesting financial

"Restricted Stock Vesting Under a Registered Plan"

Restricted stock vesting is the timetable and conditions under which shares granted to employees or insiders become fully owned and can be sold, typically requiring continued work or meeting performance goals. It matters to investors because large blocks of shares can become tradable at once, which can change share supply and price, and because vesting aligns insiders’ incentives with the company’s long‑term performance—think of it like a timed unlock that both rewards and locks in key people.

Registered Plan financial

"Restricted Stock Vesting Under a Registered Plan"

A registered plan is a savings or investment account that a government recognizes for special tax treatment and rules, such as limits on how much you can put in and conditions for withdrawals. For investors it matters because those rules change how much of your gains are taxed, how quickly your money can be accessed and what strategies make sense — like a labeled jar that gives tax breaks but comes with rules about when and how you can take the money out.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction does this Form 144 report for AMPX?

The notice reports that Thomas M. Stepien plans to sell 8,000 shares of Amprius Technologies, Inc. common stock under Rule 144, related to restricted stock vesting on August 20, 2026 under a registered plan, with consideration described as services rendered.

How many AMPX shares is Thomas M. Stepien planning to sell in this filing?

Thomas M. Stepien is planning to sell 8,000 shares of Amprius Technologies, Inc. common stock. These shares are associated with restricted stock vesting under a registered plan on August 20, 2026, with the issuer listed as Amprius and consideration noted as services rendered.

What AMPX insider sales were made by Thomas M. Stepien in the past three months?

Over the past three months, Thomas M. Stepien reported selling 23,529 shares for $243,312.64 on August 20, 2026; 2,000 shares for $41,940.00 on June 4, 2026; and 4,375 shares for $75,221.56 on May 27, 2026.

Which broker is handling the planned AMPX share sale in this Form 144?

The planned sale of 8,000 Amprius Technologies, Inc. shares is indicated as being handled through Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, 8th Floor, New York, NY 10004.

What type of AMPX securities are involved in this Form 144 filing?

The filing concerns common stock of Amprius Technologies, Inc. The 8,000 shares to be sold arise from restricted stock vesting on August 20, 2026 under a registered plan, with consideration identified as services rendered to the issuer.

What is the aggregate value associated with the recent AMPX insider sales reported?

Recent reported sales by Thomas M. Stepien include $243,312.64 on 23,529 shares, $41,940.00 on 2,000 shares, and $75,221.56 on 4,375 shares of Amprius Technologies, Inc. common stock over the three-month period covered.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/24/2026 - 04:08 PM EDT Accepted by SEC EDGAR 08/24/2026 - 04:08 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0002067233
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	AMPRIUS TECHNOLOGIES, INC.
SEC File Number	001-41314
Address of Issuer	1180 PAGE AVENUE FREMONT CALIFORNIA 94538
Phone	(800) 425-8803
Name of Person for Whose Account the Securities are To Be Sold	THOMAS M STEPIEN
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	8000	80240.00	146081000	08/24/2026	NYSE

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/20/2026	Restricted Stock Vesting Under a Registered Plan	Issuer			8000	08/20/2026	Services Rendered

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
THOMAS M STEPIEN 1180 Page Avenue Fremont CA 94538	Common	08/20/2026	23529	243312.64
THOMAS M STEPIEN 1180 Page Avenue Fremont CA 94538	Common	06/04/2026	2000	41940.00
THOMAS M STEPIEN 1180 Page Avenue Fremont CA 94538	Common	05/27/2026	4375	75221.56

144: Remarks and Signature

Remarks
Date of Notice	08/24/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Thomas M Stepien
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)