David H. Wang, a director, officer, and 10% owner of ACM Research, Inc. (NASDAQ:ACMR), filed a Form 4 on September 10, 2026, disclosing stock option exercises and open-market sales of Class A Common Stock on September 8 and September 9, 2026, pursuant to a Rule 10b5-1 trading plan.

Key Highlights

  • Two option exercises: Wang exercised stock options for 70,000 shares each on September 8 and September 9, 2026, at an exercise price of $1 per share, with the options described as fully vested and exercisable.
  • Total shares sold across two days: Wang disposed of 70,000 shares on September 8 and 70,000 shares on September 9, 2026, through multiple transactions at weighted average prices ranging from approximately $73.80 to $78.57.
  • Rule 10b5-1 plan: All sales were effected pursuant to a Rule 10b5-1 trading plan adopted by Wang on June 5, 2026.
  • Remaining direct ownership: Following all reported transactions, Wang directly held 802,708 shares of Class A Common Stock.
  • Indirect holdings: Wang also holds indirect beneficial ownership of 100,002 shares through his wife Jing Chen, 180,000 shares through the David Hui Wang and Jing Chen Family Irrevocable Trust for Wang Children, and 620,001 shares through the Wang-Chen Family Living Trust.
  • Remaining options: After both exercises, Wang held 130,000 stock options (at $1 exercise price) expiring December 27, 2026.

Wang's Two-Day Option Exercise and Share Sale Activity at ACM Research

According to the filing, Wang executed two separate stock option exercises on September 8 and September 9, 2026, each involving 70,000 shares of Class A Common Stock at an exercise price of $1 per share. The filing notes that the options were fully vested and exercisable at the time of exercise. Following each exercise, Wang sold the equivalent number of shares through multiple open-market transactions on the same day, reducing his direct holdings back to 802,708 shares by the end of September 9, 2026.

On September 8, 2026, the filing reports four separate sale tranches: 4,803 shares at a weighted average price of $75.99, 51,374 shares at $77.15, 12,323 shares at $78.08, and 1,500 shares at $78.57. On September 9, 2026, five tranches were reported: 33,493 shares at $73.80, 18,934 shares at $74.67, 11,666 shares at $75.58, 4,807 shares at $76.73, and 1,100 shares at $77.59. All prices listed are weighted averages; the filing states that full information on the number of shares sold at each separate price within each range is available upon request to the issuer, any security holder, or SEC staff.

The filing identifies Wang as a director, 10% owner, and officer of ACM Research, Inc. In addition to his direct stake of 802,708 shares, he retains indirect beneficial ownership through family and trust vehicles totaling an additional 900,003 shares. The remaining stock options, totaling 130,000 shares, carry a $1 exercise price and expire December 27, 2026, according to the filing.

What Was Disclosed

The Form 4 discloses that David H. Wang exercised 140,000 stock options at $1 per share and sold 140,000 shares of ACM Research Class A Common Stock across September 8-9, 2026, under a pre-established Rule 10b5-1 plan, leaving him with 802,708 directly held shares and 130,000 remaining options.