Amprius Technologies (AMPX) CTO Reports December Option Exercise and Sale

Rhea-AI Filing Summary

Amprius Technologies’ Chief Technology Officer reported option exercises and share sales in December. On 12/11/2025, he exercised stock options for 125,000 shares of common stock at an exercise price of $0.05 per share, increasing his direct holdings.

On the same date, he sold 198,255 shares of common stock at an average price of $10.5086 per share, with individual trade prices ranging from $10.14 to $11.49. After these transactions, he directly held 748,696 shares, which includes 585,697 restricted stock units that vest over time, and 310,962 stock options remained outstanding. The exercises and sales were carried out under a Rule 10b5-1 trading plan adopted on September 11, 2025.

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

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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)
12/11/2025

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	12/11/2025		M(1)		125,000	A	$0.05	946,951(2)	D
Common stock	12/11/2025		S(1)		198,255	D	$10.5086(3)	748,696(2)	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
Stock Option (right to buy)	$0.05	12/11/2025		M(1)			125,000	09/14/2022	03/15/2027	Common stock	125,000	$0	310,962	D

Explanation of Responses:

1. The exercises and sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 11, 2025.

2. 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.

3. The price reported in Column 4 is an average execution price. These shares were sold in multiple transactions at prices ranging from $10.14 to $11.49, 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.

Remarks:

	/s/ Ricardo C. Rodriguez, attorney-in-fact on behalf of Constantin Ionel Stefan	12/15/2025
	** 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 transactions did Amprius Technologies (AMPX) report for its CTO?

The Chief Technology Officer of Amprius Technologies (AMPX) reported exercising stock options for 125,000 shares at $0.05 per share and selling 198,255 shares of common stock on 12/11/2025.

How many AMPX shares did the CTO sell and at what price?

The CTO sold 198,255 shares of Amprius Technologies common stock at an average price of $10.5086 per share, with trade prices ranging from $10.14 to $11.49.

What stock options did the Amprius CTO exercise in this Form 4?

He exercised a stock option (right to buy) covering 125,000 shares of common stock at an exercise price of $0.05 per share on 12/11/2025.

How many Amprius (AMPX) shares does the CTO own after the reported transactions?

Following the reported transactions, the CTO beneficially owned 748,696 shares of Amprius common stock, including 585,697 restricted stock units.

Does the Amprius CTO still hold stock options after this transaction?

Yes. After the option exercise, the CTO held 310,962 stock options beneficially, in addition to his common stock and restricted stock units.

Were the Amprius CTO’s trades made under a Rule 10b5-1 trading plan?

Yes. The option exercises and share sales were effected pursuant to a Rule 10b5-1 trading plan adopted by the CTO on September 11, 2025.

What portion of the Amprius CTO’s holdings are restricted stock units (RSUs)?

Of the CTO’s reported holdings, 585,697 units are restricted stock units, each representing a contingent right to receive one share of Amprius common stock, subject to vesting conditions.