X0306 4 2021-03-18 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 Class A Common Stock 2021-03-18 4 S 0 50000 91.92 D 217234 D Class A Common Stock 2021-03-19 4 S 0 49228 90.55 D 168006 D Class A Common Stock 33334 I By Jing Chen, wife of David H. Wang Class A Common Stock 15279 I By Sophia Wang, daughter of David H. Wang Class A Common Stock 60000 I By David Hui Wang and Jing Chen Family Irrevocable Trust for Wang Children Class A Common Stock 206667 I By Wang-Chen Family Living Trust The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. Chief Executive Officer, President and Director /s/ Mark L. Johnson, Attorney-in-Fact for David H. Wang 2021-03-22