Amprius CTO sells 3,208 shares to cover RSU taxes

Amprius Technologies, Inc. Chief Technology Officer Stefan Constantin Ionel reported an open-market sale of 3,208 shares of common stock at an average price of $17.1935 per share.

Rhea-AI Filing Summary

Amprius Technologies, Inc. Chief Technology Officer Stefan Constantin Ionel reported an open-market sale of 3,208 shares of common stock at an average price of $17.1935 per share. The sale was executed under non-discretionary, sell-to-cover arrangements mandated by the company to fund tax withholding on vested restricted stock units.

Following this tax-related sale, Ionel beneficially owns 801,310 shares, including 584,308 restricted stock units that each represent the right to receive one share of common stock, subject to vesting conditions.

Insider Trade Summary

Net Seller: 3,208 shares

Net Sell 1 txn

Insider Stefan Constantin Ionel

Role Chief Technology Officer

Sold 3,208 shs ($55K)

Type	Security	Shares	Price	Value
Sale	Common stock	3,208	$17.1935	$55K

Holdings After Transaction: Common stock — 801,310 shares (Direct)

Footnotes (3)

1. F1. 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. F2. The price reported in Column 4 is an average execution price. These shares were sold in multiple transactions at prices ranging from $17.13 to $17.3, 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. F3. Includes 584,308 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.

Key Figures

Shares sold: 3,208 shares Average sale price: $17.1935 per share Price range: $17.13–$17.30 per share +2 more

5 metrics

Shares sold 3,208 shares Open-market sale on 2026-05-27

Average sale price $17.1935 per share Open-market sale on 2026-05-27

Price range $17.13–$17.30 per share Multiple executions underlying reported average price

Shares owned after 801,310 shares Common stock beneficially owned after transaction

Restricted stock units 584,308 RSUs Each RSU represents a contingent right to one share

Key Terms

restricted stock units, sell-to-cover arrangements, open-market sale, beneficially owns, +1 more

5 terms

restricted stock units financial

"Includes 584,308 restricted stock units, each of which represents a contingent right to receive one share"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

sell-to-cover arrangements financial

"non-discretionary, sell-to-cover arrangements mandated by the issuer to fund tax withholding obligations"

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

beneficially owns financial

"Following this tax-related sale, Ionel beneficially owns 801,310 shares"

Beneficially owns means a person or entity enjoys the economic benefits and control of a security even if the legal title or registration is held in another name. Think of it like having the keys and profits from a car that is registered to a friend: you use it, benefit from it, and make decisions about it even though the official paperwork lists someone else. For investors, this matters because it reveals who truly controls shares, affects voting power, potential conflicts of interest, and regulatory disclosure obligations.

vesting financial

"in connection with the vesting of restricted stock units"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

FAQ

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

What insider transaction did Amprius Technologies (AMPX) report for Stefan Constantin Ionel?

Amprius Technologies reported that CTO Stefan Constantin Ionel sold 3,208 shares of common stock. The sale was an open-market transaction used to cover tax withholding obligations tied to the vesting of restricted stock units.

At what price did the Amprius Technologies (AMPX) CTO sell shares in this Form 4?

The CTO’s 3,208 shares were sold at an average price of $17.1935 per share. Footnotes state trades occurred in multiple executions between $17.13 and $17.30, with the average reported as the transaction price.

Was the AMPX insider sale by the CTO discretionary or tax-related?

The sale was tax-related, not discretionary. Footnotes explain it was effected under non-discretionary, sell-to-cover arrangements mandated by Amprius Technologies to fund tax withholding when restricted stock units vested.

How many Amprius Technologies (AMPX) shares does the CTO hold after this Form 4 transaction?

After the transaction, the CTO holds 801,310 shares of Amprius Technologies common stock. This total includes 584,308 restricted stock units, each representing a contingent right to receive one share, subject to vesting schedules and conditions.

What are the restricted stock units held by the Amprius Technologies (AMPX) CTO?

The CTO holds 584,308 restricted stock units. Each unit represents a contingent right to receive one share of Amprius Technologies common stock, provided specific vesting schedules and other applicable conditions for each award are satisfied over time.

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

Form 4 Insider Transactions: What Each Field Means →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Accepted by SEC EDGAR 05/28/2026 - 06:12 PM Learn about SEC filing dates

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 CALIFORNIA 94538

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/27/2026

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

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

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

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	05/27/2026		S(1)		3,208	D	$17.1935(2)	801,310(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 $17.13 to $17.3, 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 584,308 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:

	/s/ Ricardo C. Rodriguez, attorney-in-fact on behalf of Constantin Ionel Stefan	05/28/2026
	** 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.
* Form 4: SEC 1474 (03-26)