X0306 4 2020-06-15 0001680062 ACM Research, Inc. ACMR 0001775007 McKechnie Mark C/O ACM RESEARCH, INC. 42307 OSGOOD ROAD, SUITE I FREMONT CA 94539 true See remarks Class A Common Stock 2020-06-15 4 M 0 5415 13.85 A 5415 D Class A Common Stock 2020-06-15 4 S 0 5415 54.34 D 0 D Stock Option 13.85 2020-06-15 4 M 0 5415 0 D 2028-07-31 Class A Common Stock 5415 34585 D On June 15, 2020, the reporting person exercised previously issued stock options to purchase 5,415 shares of Class A Common Stock of the Issuer. The sale reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. The option vested and became exercisable as to 10,000 shares on August 1, 2019, and the remaining 30,000 shares vest and become exercisable in equal monthly installments over the following 36 months, subject to continued service through each vesting date. Chief Financial Officer and Treasurer /s/ Mark L. Johnson, Attorney-in-Fact for Mark McKechnie 2020-06-17