Acm Research, Inc.
A maker of wet-cleaning machines that keep semiconductor chips free of tiny particles during manufacturing, sold largely to chip fabs in mainland China under technologies like SAPS, TEBO, and Tahoe. It also builds electroplating, furnace, and packaging tools. Founded in 1998 in Silicon Valley by Dr. David Wang, it pivoted from stress-free copper polishing to cleaning after early tools struggled commercially. Its name "ACM" originally stood for "Advanced Copper Materials," a nod to its first copper-polishing ambition.
Granted 600.0K · Sold 470.0K
Granted 15.0K · Sold 15.0K
Granted 30.0K · Sold 30.0K
Granted 75.0K · Sold 75.0K
Granted 28.8K · Sold 28.8K
Granted 60.0K · Sold 60.0K
Granted 10.0K · Sold 10.0K
Granted 185.0K · Sold 185.0K
Granted 120.0K · Sold 120.0K
| Insider | Stake change | Holds now | Granted / vested | Bought | Sold |
|---|---|---|---|---|---|
| Wang David HSee Remarks, Director, 10% owner · 32 transactions | +4.2% | 1.75M | 600.0K | — | 470.0K |
| Dun HaipingDirector · 13 transactions | — | 855.1K | 15.0K | — | 15.0K |
| Wang JianSee remarks · 2 transactions | 0% | 253.2K | 30.0K | — | 30.0K |
| Liu TracyDirector · 8 transactions | -9.2% | 114.1K | 75.0K | — | 75.0K |
| Cheav SothearaSee remarks · 11 transactions | -10% | 100.0K | 28.8K | — | 28.8K |
| Feng LisaSee remarks · 10 transactions | 0% | 50.0K | 60.0K | — | 60.0K |
| Pappis Charles CDirector · 4 transactions | — | 5.0K | 10.0K | — | 10.0K |
| McKechnie MarkSee Remarks · 18 transactions | 0% | 900 | 185.0K | — | 185.0K |
| Chen FupingSee remarks · 5 transactions | -100% | 0 | 120.0K | — | 120.0K |
Select a row to see that insider’s individual transactions. Sum of the holdings confirmed in the 12 months before this insider's last filing. A Form 4 reports a holding per line — held directly, or through a named trust, partnership or foundation, and in each share class separately — never a person’s total. Lines not restated in that time are left out and shown apart: an active filer restates what they still hold, so a line they did not restate is more often an entity since renamed, whose shares a successor line reports too. An amber marker means some were left out.
Net open-market activity over the last year: -993.8K shares. Grants, option exercises and tax withholding are excluded — they are compensation mechanics, not decisions to buy or sell.