Constantin Ionel Stefan - 21 Jan 2026 Form 4 Insider Report for Amprius Technologies, Inc. (AMPX)

Role
Chief Technology Officer
Signature
/s/ Ricardo C. Rodriguez, attorney-in-fact on behalf of Constantin Ionel Stefan
Issuer symbol
AMPX
Transactions as of
21 Jan 2026
Net transactions value
-$6,749,329
Form type
4
Filing time
23 Jan 2026, 17:36:48 UTC
Previous filing
15 Dec 2025
Next filing
30 Jan 2026
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Stefan Constantin Ionel Chief Technology Officer C/O AMPRIUS TECHNOLOGIES, INC.,, 1180 PAGE AVENUE, FREMONT /s/ Ricardo C. Rodriguez, attorney-in-fact on behalf of Constantin Ionel Stefan 23 Jan 2026 0001940928

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction AMPX Common stock Options Exercise $25,769 +41,563 +5.6% $0.6200 790,259 21 Jan 2026 Direct F1, F2
transaction AMPX Common stock Options Exercise $792 +15,834 +2% $0.0500 806,093 21 Jan 2026 Direct F1, F2
transaction AMPX Common stock Options Exercise $794 +15,883 +2% $0.0500 821,976 21 Jan 2026 Direct F1, F2
transaction AMPX Common stock Sale $879,411 -73,280 -8.9% $12.00 748,696 21 Jan 2026 Direct F1, F2, F3
transaction AMPX Common stock Options Exercise $12,696 +253,928 +34% $0.0500 1,002,624 22 Jan 2026 Direct F1, F2
transaction AMPX Common stock Options Exercise $32,758 +72,795 +7.3% $0.4500 1,075,419 22 Jan 2026 Direct F1, F2
transaction AMPX Common stock Options Exercise $8,305 +166,104 +15% $0.0500 1,241,523 22 Jan 2026 Direct F1, F2
transaction AMPX Common stock Sale $5,931,912 -492,827 -40% $12.04 748,696 22 Jan 2026 Direct F1, F2, F4
transaction AMPX Common stock Options Exercise $80 +1,600 +0.21% $0.0500 750,296 23 Jan 2026 Direct F1, F2
transaction AMPX Common stock Sale $19,200 -1,600 -0.21% $12.00 748,696 23 Jan 2026 Direct F1, F2, F5

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction AMPX Stock Option (right to buy) Options Exercise $0 -41,563 -100% $0.000000 90 21 Jan 2026 Common stock 41,563 $0.6200 Direct F1
transaction AMPX Stock Option (right to buy) Options Exercise $0 -15,834 -5.1% $0.000000 295,128 21 Jan 2026 Common stock 15,834 $0.0500 Direct F1
transaction AMPX Stock Option (right to buy) Options Exercise $0 -15,883 -8.7% $0.000000 166,104 21 Jan 2026 Common stock 15,883 $0.0500 Direct F1
transaction AMPX Stock Option (right to buy) Options Exercise $0 -253,928 -86% $0.000000 41,200 22 Jan 2026 Common stock 253,928 $0.0500 Direct F1
transaction AMPX Stock Option (right to buy) Options Exercise $0 -72,795 -100% $0.000000 0 22 Jan 2026 Common stock 72,795 $0.4500 Direct F1
transaction AMPX Stock Option (right to buy) Options Exercise $0 -166,104 -100% $0.000000 0 22 Jan 2026 Common stock 166,104 $0.0500 Direct F1
transaction AMPX Stock Option (right to buy) Options Exercise $0 -1,600 -3.9% $0.000000 39,600 23 Jan 2026 Common stock 1,600 $0.0500 Direct F1
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 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.
F2 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.
F3 The price reported in Column 4 is an average execution price. These shares were sold in multiple transactions at prices ranging from $12.00 to $12.01, 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.
F4 The price reported in Column 4 is an average execution price. These shares were sold in multiple transactions at prices ranging from $12.00 to $12.135, 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.
F5 These shares were sold at $12.00. 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 shares sold.