Form 4 Filing for ACM Research, Inc.

On September 8, 2026, David H. Wang, a director, officer, and 10% owner of ACM Research, Inc., acquired 70,000 shares of Class A Common Stock at $1.00 per share. On the same day, he disposed of 4803 shares at an average price of $75.99, 51374 shares at an average price of $77.15, 12323 shares at an average price of $78.08, and 1500 shares at an average price of $78.57. These transactions were executed under a Rule 10b5-1 trading plan. Additionally, on September 9, 2026, Wang acquired another 70,000 shares at $1.00 per share. He then disposed of 33493 shares at an average price of $73.80, 18934 shares at an average price of $74.67, 11666 shares at an average price of $75.58, 4807 shares at an average price of $76.73, and 1100 shares at an average price of $77.59, also under the trading plan. Derivative transactions included the acquisition of 70,000 stock options on both September 8 and 9, 2026, with a conversion or exercise price of $1.00 and expiration on December 27, 2026. Following these transactions, Wang directly owns 802,708 shares of Class A Common Stock, with additional indirect holdings through various trusts and his wife.