David H. Wang - 04 Feb 2026 Form 4 Insider Report for ACM Research, Inc. (ACMR)

Role: Chief Executive Officer, President and Director, Director, 10%+ Owner
Signature: /s/ Mark McKechnie, Attorney-in-Fact for David H. Wang
Issuer symbol: ACMR
Transactions as of: 04 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 06 Feb 2026, 16:30:18 UTC
Previous filing: 05 Dec 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Wang David H	Chief Executive Officer, President and Director, Director, 10%+ Owner	C/O ACM RESEARCH, INC., 42307 OSGOOD ROAD, SUITE I, FREMONT	/s/ Mark McKechnie, Attorney-in-Fact for David H. Wang	06 Feb 2026	0001721580

Transactions Table

Type	Sym	Class	Shares After	Date	Ownership
holding	ACMR	Class A Common Stock	100,002	04 Feb 2026	By Jing Chen, wife of David H. Wang
holding	ACMR	Class A Common Stock	45,837	04 Feb 2026	By Sophia Wang, daughter of David H. Wang
holding	ACMR	Class A Common Stock	180,000	04 Feb 2026	By David Hui Wang and Jing Chen Family Irrevocable Trust for Wang Children
holding	ACMR	Class A Common Stock	620,001	04 Feb 2026	By Wang-Chen Family Living Trust

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	ACMR	Stock Option	Award	$0	+545,400	+50%	$0.000000	1,636,197	04 Feb 2026	Class A Common Stock	545,400	$7.36	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	On March 20, 2020, the reporting person was granted options to purchase an aggregate of 1,636,197 shares of the Issuer's Class A common stock, based on the satisfaction of certain performance criteria. In general, one-third of the shares subject to the options vest and become exercisable upon an increase in the Issuer's market capitalization (calculated as described in footnote 2) of $1 billion, $2 billion and $3 billion, respectively, from the market capitalization of $553,383,586 on the date of grant. 545,400 shares vested and became exercisable on February 4, 2026, which was the first trading day as of which the Issuer's market capitalization equaled or exceeded $3,553,383,586.
F2	For purposes of the options, the market capitalization as of a specified trading day is calculated by multiplying (a) the average of the daily volume-weighted average price per share of the Issuer's Class A common stock for each of the trading days occurring during the thirty calendar day period ending on that specified trading day by (b) the total number of issued and outstanding shares of the Issuer's Class A and Class B common stock as of 11:59 p.m. (Eastern time) on such specified trading day.

Content

On March 20, 2020, the reporting person was granted options to purchase an aggregate of 1,636,197 shares of the Issuer's Class A common stock, based on the satisfaction of certain performance criteria. In general, one-third of the shares subject to the options vest and become exercisable upon an increase in the Issuer's market capitalization (calculated as described in footnote 2) of $1 billion, $2 billion and $3 billion, respectively, from the market capitalization of $553,383,586 on the date of grant. 545,400 shares vested and became exercisable on February 4, 2026, which was the first trading day as of which the Issuer's market capitalization equaled or exceeded $3,553,383,586.

For purposes of the options, the market capitalization as of a specified trading day is calculated by multiplying (a) the average of the daily volume-weighted average price per share of the Issuer's Class A common stock for each of the trading days occurring during the thirty calendar day period ending on that specified trading day by (b) the total number of issued and outstanding shares of the Issuer's Class A and Class B common stock as of 11:59 p.m. (Eastern time) on such specified trading day.

Remarks:

Chief Executive Officer, President and Director