Acm Research Inc
Ownership
Ownership Structure
Who owns Acm Research Inc (ACMR)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 95.1% of the shares are freely tradable; institutional investors hold 74.2%.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| BlackRock Inc | 12.43 | 8,660,842 | +8.5 | 06/30/2026 |
| Vanguard Portfolio Management, LLC | 4.81 | 3,349,436 | +52.0 | 06/30/2026 |
| Vanguard Capital Management, LLC | 3.54 | 2,462,745 | +8.8 | 06/30/2026 |
| Capital World Investors | 3.44 | 2,398,036 | +0.0 | 06/30/2026 |
| State Street Corp | 3.14 | 2,188,254 | +9.1 | 06/30/2026 |
| Geode Capital Management, LLC | 2.14 | 1,487,797 | +8.5 | 06/30/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| iShares Core S&P Small-Cap ETF | 5.03 | 3,501,800 | +0.0 | 09/30/2026 |
| American Funds SMALLCAP World A | 4.23 | 2,945,654 | +0.6 | 09/30/2026 |
| Vanguard MStar Total Stk Mkt Idx Invest | 2.66 | 1,851,765 | +5.6 | 09/30/2026 |
| iShares Russell 2000 ETF | 2.11 | 1,471,657 | -1.1 | 09/30/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Wang David H | See Remarks | 802,708 | 36,523,214 $ | Sep 9, 2026 | direct |
| McKechnie Mark | See Remarks | 900 | 40,950 $ | Aug 20, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Sep 9, 2026 | Wang David H | See Remarks | Sell | 1,100 | 77.59 | 85,349 |
| Sep 9, 2026 | Wang David H | See Remarks | Sell | 4,807 | 76.73 | 368,841 |
| Sep 9, 2026 | Wang David H | See Remarks | Sell | 11,666 | 75.58 | 881,716 |
| Sep 9, 2026 | Wang David H | See Remarks | Sell | 18,934 | 74.67 | 1,413,802 |
| Sep 9, 2026 | Wang David H | See Remarks | Sell | 33,493 | 73.80 | 2,471,783 |
| Sep 9, 2026 | Wang David H | See Remarks | Other | 70,000 | 1.00 | 70,000 |
| Sep 8, 2026 | Wang David H | See Remarks | Sell | 1,500 | 78.57 | 117,855 |
| Sep 8, 2026 | Wang David H | See Remarks | Sell | 12,323 | 78.08 | 962,180 |
| Sep 8, 2026 | Wang David H | See Remarks | Sell | 51,374 | 77.15 | 3,963,504 |
| Sep 8, 2026 | Wang David H | See Remarks | Sell | 4,803 | 75.99 | 364,980 |
| Sep 8, 2026 | Wang David H | See Remarks | Other | 70,000 | 1.00 | 70,000 |
| Aug 20, 2026 | McKechnie Mark | See Remarks | Sell | 11,209 | 77.89 | 873,069 |
| Aug 20, 2026 | McKechnie Mark | See Remarks | Sell | 30,365 | 77.45 | 2,351,769 |
| Aug 20, 2026 | McKechnie Mark | See Remarks | Sell | 13,625 | 76.34 | 1,040,133 |
| Aug 20, 2026 | McKechnie Mark | See Remarks | Other | 25,000 | 13.89 | 347,250 |
| Aug 20, 2026 | McKechnie Mark | See Remarks | Other | 30,199 | 19.49 | 588,579 |
| Aug 18, 2026 | Dun Haiping | Director | Sell | 400 | 82.17 | 32,868 |
| Aug 18, 2026 | Dun Haiping | Director | Sell | 3,400 | 81.31 | 276,454 |
| Aug 18, 2026 | Dun Haiping | Director | Sell | 1,200 | 80.29 | 96,348 |
| Aug 18, 2026 | Dun Haiping | Director | Other | 5,000 | 5.60 | 28,000 |
| Apr 17, 2026 | Charles C Pappis | Director | Sell | 5,000 | 52.00 | 260,000 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: October 30, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.