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.
Sold 1.10M
Sold 1.10M
Granted 1.93M · Sold 1.60M
Granted 502.3K · Sold 474.2K
Granted 210.0K · Sold 210.0K
Granted 127.5K · Sold 127.5K
Granted 137.5K · Sold 167.5K
Sold 163.3K
Granted 152.4K · Sold 150.0K
Granted 10.0K · Sold 10.0K
Granted 328.1K · Sold 327.8K
Granted 225.0K · Sold 225.0K
| Insider | Stake change | Holds now | Granted / vested | Bought | Sold |
|---|---|---|---|---|---|
| Shanghai Pudong Science & Technology Investment Group Co., Ltd. +1 co-filer10% owner, Possible member of 10% group · 8 transactions | — | 5.70Mas of Oct 2024 | — | — | 1.10M |
| Xing XiaoDirector · 8 transactions | — | 2.34Mas of Oct 2024 | — | — | 1.10M |
| Wang David HSee Remarks, Director, 10% owner · 72 transactions | +261.8% | 1.75M | 1.93M | — | 1.60M |
| Dun HaipingDirector · 68 transactions | — | 855.1K | 502.3K | — | 474.2K |
| Wang JianSee remarks · 15 transactions | +200% | 253.2K | 210.0K | — | 210.0K |
| Liu TracyDirector · 16 transactions | +209.1% | 114.1K | 127.5K | — | 127.5K |
| Cheav SothearaSee remarks · 31 transactions | +130.8% | 100.0K | 137.5K | — | 167.5K |
| Hu ChenmingDirector · 1 transaction | +13.9% | 100.0Kas of Mar 2025 | — | — | 163.3K |
| Feng LisaSee remarks · 26 transactions | +251.4% | 50.0K | 152.4K | — | 150.0K |
| Pappis Charles CDirector · 4 transactions | — | 5.0K | 10.0K | — | 10.0K |
| McKechnie MarkSee Remarks · 54 transactions | -82% | 900 | 328.1K | — | 327.8K |
| Chen FupingSee remarks · 8 transactions | — | 0 | 225.0K | — | 225.0K |
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 5 years: -5.66M shares. Grants, option exercises and tax withholding are excluded — they are compensation mechanics, not decisions to buy or sell.