How fast must insiders report trades? (Form 4 deadlines)

Since Sarbanes-Oxley in 2002, Section 16 insiders must report a trade on Form 4 before the end of the second business day after the transaction. Trade on Monday, file by Wednesday. Before 2002 the deadline was the 10th of the following month — up to 40 days of lag; today the market learns about insider trades while they're still fresh.

The practical timeline

• Day 0: the insider trades (the "transaction date" on the form).
• Day 1–2: counsel or the insider's broker prepares and files the Form 4 electronically on SEC EDGAR. Filings appear publicly within seconds of acceptance, and EDGAR accepts them until 10 p.m. Eastern.
• Late filings happen — a small percentage arrive days or even months late (the form has a box for explaining). Late Form 4s still get processed; it's why historical data occasionally shows a "new" buy with an old transaction date.

Why the two-day rule matters for cluster detection

Because every insider is on the same two-day clock, a genuine burst of buying shows up on EDGAR as a burst of filings. That's what makes cluster buys detectable in near-real-time: we poll EDGAR continuously, parse each Form 4 as it lands, and alert the moment a second distinct insider buys the same stock within the window. Paid subscribers get that alert while the window is still open — see pricing.