X0508 4 2025-10-27 0001680062 ACM Research, Inc. ACMR 0001721580 Wang David H C/O ACM RESEARCH, INC. 42307 OSGOOD ROAD, SUITE I FREMONT CA 94539 true true true See Remarks false Class A Common Stock 100002 I By Jing Chen, wife of David H. Wang Class A Common Stock 45837 I By Sophia Wang, daughter of David H. Wang Class A Common Stock 180000 I By David Hui Wang and Jing Chen Family Irrevocable Trust for Wang Children Class A Common Stock 620001 I By Wang-Chen Family Living Trust Stock Option 7.36 2025-10-27 4 A 0 545400 0 A 2030-03-19 Class A Common Stock 545400 545400 D 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 October 27, 2025, which was the first trading day as of which the Issuer's market capitalization equaled or exceeded $2,553,383,586. The remaining shares will vest and become exercise upon the first trading days, if any, on which the Issuer's market capitalization equals or exceeds $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. Chief Executive Officer, President and Director /s/ Mark McKechnie, Attorney-in-Fact for David H. Wang 2025-10-29