X0508 4/A 2023-08-10 2023-08-14 0001680062 ACM Research, Inc. ACMR 0001779777 Feng Lisa C/O ACM RESEARCH, INC. 42307 OSGOOD ROAD, SUITE I FREMONT CA 94539 true See remarks false Stock Option 13.89 2023-08-10 4 A 0 100000 0 D 2033-08-09 Class A Common Stock 100000 100000 D This Form 4 amendment has been filed solely to correct the exercise price of the stock option to purchase shares of Class A Common Stock of the Issuer reported in a Form 4 filed on August 14, 2023 (the "Form 4"). The exercise price was inadvertently stated as $13.24 in the Form 4. The exercise price should have been stated as $13.89 in the Form 4. The option will vest and become exercisable as to 25,000 shares on August 10, 2024 and the remaining 75,000 shares will vest and become exercisable in equal monthly installments over the following 36 months, subject to continued service through each vesting date. Chief Financial Officer of ACM Research (Shanghai), Inc., a subsidiary of the Issuer /s/ Mark McKechnie, Attorney-in-Fact for Lisa Feng 2023-08-21