X0508 4 2024-03-13 0001680062 ACM Research, Inc. ACMR 0001721279 Cheav Sotheara C/O ACM RESEARCH, INC. 42307 OSGOOD ROAD, SUITE I FREMONT CA 94539 true See remarks true Class A Common Stock 2024-03-13 4 S 0 5000 29.09 D 105002 D Class A Common Stock 2024-03-14 4 S 0 2617 27.49 D 102385 D Class A Common Stock 2024-03-14 4 S 0 2383 28.32 D 100002 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 13, 2023. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $28.80 to $29.41, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (3) and (4) to this Form 4. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $27.03 to $27.88, inclusive. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $28.10 to $28.53, inclusive. Senior Vice President, Manufacturing of ACM Research (Shanghai), Inc., a subsidiary of the Issuer. /s/ Mark McKechnie, Attorney-in-Fact for Sotheara Cheav 2024-03-15