X0508 4 2026-03-11 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 true Class A Common Stock 2026-03-11 4 M 0 60000 1 A 862708 D Class A Common Stock 2026-03-11 4 S 0 55373 47.89 D 807335 D Class A Common Stock 2026-03-11 4 S 0 4627 48.34 D 802708 D Class A Common Stock 2026-03-12 4 M 0 50000 1 A 852708 D Class A Common Stock 2026-03-12 4 S 0 10561 44.92 D 842147 D Class A Common Stock 2026-03-12 4 S 0 38737 45.74 D 803410 D Class A Common Stock 2026-03-12 4 S 0 702 46.57 D 802708 D 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 1 2026-03-11 4 M 0 60000 0 D 2026-12-27 Class A Common Stock 60000 420002 D Stock Option 1 2026-03-12 4 M 0 50000 0 D 2026-12-27 Class A Common Stock 50000 370002 D The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 29, 2024. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $47.23 to $48.22, 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 footnote (2), (3), (4), (5), and (6) 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 $48.23 to $48.61, inclusive. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $44.40 to $45.39, inclusive. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.40 to $46.39, inclusive. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $46.45 to $46.59, inclusive. The option is fully vested and exercisable. Chief Executive Officer, President and Director /s/ Mark McKechnie, Attorney-in-Fact for David H. Wang 2026-03-13