About this page
Insider trades reported on SEC Form 4: when the people who run a company buy or sell its shares with their own money.
How to read it
- Form 4
- The form a company insider (officer, director or owner of more than 10%) must file with the SEC within two business days of buying or selling the company's shares.
- Buy (P) and Sell (S)
- Open-market purchases and sales. Gifts, option exercises and automatic tax withholding are left out because they say little about what the insider thinks.
- Value
- Shares times price, as reported on the filing.
- 10b5-1
- A trade made under a plan set up in advance. Planned sales are common and usually say less than an unplanned purchase.
- Late filing
- A Form 4 filed more than two business days after the trade.
- Vs. S&P 500
- How the stock did after the trade minus how the overall market did in the same weeks.
A real example
In January 2016, when bank stocks were falling, JPMorgan Chase CEO Jamie Dimon bought 500,000 JPMorgan shares with his own money, worth about $26 million. His Form 4 made the purchase public within days, and investors read it as a strong sign of confidence.
Explain it like I'm 13
If the coach of a team bets his own allowance that his team will win, that tells you something. A Form 4 is the note a company boss must hand in whenever he buys or sells his own company's shares, so everyone can see it.
Data from public SEC filings and congressional reports. Information, not investment advice. Check every number against the filing linked on the page.
ACM Research, Inc. (ACMR): Insider Trades and Fund Holdings
In the past 12 months, ACM Research, Inc. insiders reported no open-market purchases and 4 sales worth $15.3M; 4 of the sales were reported as made under a 10b5-1 trading plan.
Timeline: news and trades
Company filings (8-K), insider trades, notices of planned sales (Form 144), Congress trades and fund moves in the past year, newest first.
- Sep 9, 2026Insider saleSee Remarks David H. Wang sold $5.2 million under a 10b5-1 plan
- Sep 9, 2026Planned saleHUI WANG (officer, director, 10% stockholder) filed notice to sell about $5.2 million around Sep 9, 2026
- Sep 8, 2026Insider saleSee Remarks David H. Wang sold $5.4 million under a 10b5-1 plan
- Sep 8, 2026Planned saleHUI WANG (officer, director, 10% stockholder) filed notice to sell about $5.4 million around Sep 8, 2026
- Aug 20, 2026Insider saleSee Remarks Mark McKechnie sold $4.3 million under a 10b5-1 plan
- Aug 20, 2026Planned saleMARK A MCKECHNIE (officer) filed notice to sell about $4.3 million around Aug 20, 2026
- Aug 18, 2026Insider saleDirector Haiping Dun sold $405,670 under a 10b5-1 plan
- Aug 18, 2026Planned saleHAIPING DUN (director) filed notice to sell about $405,663 around Aug 18, 2026
- Aug 7, 2026NewsCompany reported: Quarterly or annual results
- Jun 30, 2026FundSoros Fund Management opened a position in Q2 2026 (13F filed Aug 14, 2026)
- Jun 30, 2026FundRenaissance Technologies added 87% in Q2 2026 (13F filed Aug 13, 2026)
Recent insider trades
Open-market purchases (code P) and sales (code S) from Form 4. Grants, option exercises and gifts are not shown. Latest filing: Sep 10, 2026.
| Filed | Insider | Type | Value |
|---|---|---|---|
| Sep 10 | David H. WangSee Remarks | ▼ SELL10b5-1 | $5.41M |
| Sep 10 | David H. WangSee Remarks | ▼ SELL10b5-1 | $5.22M |
| Aug 21 | Mark McKechnieSee Remarks | ▼ SELL10b5-1 | $4.26M |
| Aug 20 | Haiping DunDirector | ▼ SELL10b5-1 | $406K |
Insiders who traded in the past year
| Insider | Role | Buys | Bought | Sells | Sold |
|---|---|---|---|---|---|
| David H. Wang | See Remarks | 0 | $0 | 2 | $10.6M |
| Mark McKechnie | See Remarks | 0 | $0 | 1 | $4.26M |
| Haiping Dun | Director | 0 | $0 | 1 | $406K |
Tracked funds that report ACMR
From each fund's latest 13F. Holdings are as of quarter end and are filed up to 45 days later.
| Fund | Shares | Value | Change |
|---|---|---|---|
| Renaissance Technologies | 229,800 | $29.2M | ▲ +87.4% |
| Soros Fund Management | 30,122 | $3.82M | ▲ New |
Reading these numbers
Insiders sell for many reasons: taxes, diversification, a house. Purchases with their own money are rarer and are usually read as more informative. A Form 4 is due within two business days of the trade. How to read a Form 4 →