AMPX insider Form 4: CTO tax-related sale and RSU holdings

Rhea-AI Filing Summary

Amprius Technologies, Inc. insider transaction: the company’s Chief Technology Officer, Constantin Ionel Stefan, reported the sale of 25,024 shares of Amprius common stock on 11/21/2025 at an average price of $10.0813 per share, according to a Form 4 filing. The transaction is coded as a sale and was carried out under a non-discretionary sell-to-cover arrangement mandated by the company to fund tax withholding obligations tied to the vesting of restricted stock units, meaning the sale was made to cover taxes rather than as an open-market discretionary sale. After this transaction, Stefan beneficially owns 821,951 shares of Amprius common stock, which includes 585,697 restricted stock units that each represent a right to receive one share of common stock if their vesting conditions are met.

Insider Trade Summary

Net Seller: 25,024 shares ($252,274)

Net Sell 1 txn

Insider Stefan Constantin Ionel

Role Chief Technology Officer

Sold 25,024 shs ($252K)

Type	Security	Shares	Price	Value
Sale	Common stock	25,024	$10.0813	$252K

Holdings After Transaction: Common stock — 821,951 shares (Direct)

Footnotes (1)

1. This transaction was effected pursuant to non-discretionary, sell-to-cover arrangements mandated by the issuer to fund tax withholding obligations in connection with the vesting of restricted stock units. The price reported in Column 4 is an average execution price. These shares were sold in multiple transactions at prices ranging from $10.05 to $10.13, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above. Includes 585,697 restricted stock units, each of which represents a contingent right to receive one share of the issuer's common stock, subject to the applicable vesting schedule and conditions of each restricted stock unit.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Stefan Constantin Ionel

(Last) (First) (Middle)

C/O AMPRIUS TECHNOLOGIES, INC.,

1180 PAGE AVENUE

(Street)

FREMONT CA 94538

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Amprius Technologies, Inc. [ AMPX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Technology Officer

3. Date of Earliest Transaction (Month/Day/Year)
11/21/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common stock	11/21/2025		S(1)		25,024	D	$10.0813(2)	821,951(3)	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. This transaction was effected pursuant to non-discretionary, sell-to-cover arrangements mandated by the issuer to fund tax withholding obligations in connection with the vesting of restricted stock units.

2. The price reported in Column 4 is an average execution price. These shares were sold in multiple transactions at prices ranging from $10.05 to $10.13, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth above.

3. Includes 585,697 restricted stock units, each of which represents a contingent right to receive one share of the issuer's common stock, subject to the applicable vesting schedule and conditions of each restricted stock unit.

Remarks:

Exhibit 24-Power of Attorney

	/s/ Ricardo C. Rodriguez, attorney-in-fact on behalf of Constantin Ionel Stefan	11/25/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What insider transaction did AMPX report for its Chief Technology Officer?

A Form 4 shows that Amprius Technologies’ Chief Technology Officer, Constantin Ionel Stefan, sold 25,024 shares of common stock on 11/21/2025 at an average price of $10.0813 per share.

Why did the AMPX insider sell 25,024 shares?

The filing explains that the sale of 25,024 shares was done under a non-discretionary, sell-to-cover arrangement mandated by Amprius to fund tax withholding obligations related to the vesting of restricted stock units.

What price range were the AMPX shares sold at in this Form 4?

The reported average sale price is $10.0813 per share. The shares were sold in multiple transactions at prices ranging from $10.05 to $10.13 per share, inclusive.

How many AMPX shares does the insider own after this transaction?

Following the reported transaction, Constantin Ionel Stefan beneficially owns 821,951 shares of Amprius common stock, which includes restricted stock units.

How many restricted stock units does the AMPX insider hold?

The beneficial ownership total includes 585,697 restricted stock units, each representing a contingent right to receive one share of Amprius common stock, subject to vesting conditions.

Is this AMPX Form 4 filed by a single reporting person?

Yes. The Form 4 is indicated as being filed by one reporting person, covering the holdings and transaction of Constantin Ionel Stefan.

What is the insider’s role and relationship to Amprius Technologies (AMPX)?

The reporting person, Constantin Ionel Stefan, is listed as an officer of Amprius Technologies, serving as its Chief Technology Officer.