What is SEC Form 4?

Published June 11, 2026 · DisclosureSignals Team

SEC Form 4 is the most important document for tracking insider trading activity. Filed within two business days of any transaction by corporate officers, directors, and beneficial owners owning more than 10% of a company's stock, Form 4 reveals what insiders are doing with their own money — often before the rest of the market catches on.

Why Form 4 Matters for Investors

Academic research consistently shows that insider purchases are one of the strongest predictors of future stock returns. When a CEO or CFO uses their own cash to buy shares on the open market, it signals confidence that the market has undervalued the company.

• Open-market purchases (not stock grants) are the strongest signal
• Cluster buying — multiple insiders buying within 30 days — is even more predictive
• Large relative positions (increasing holdings by 20%+) show deep conviction
• Contrarian buys during stock declines often precede rebounds

How to Read a Form 4 Filing

Every Form 4 contains structured data that tells a story. Here are the key fields:

The Noise Problem

Not all Form 4 filings are meaningful. Most are routine — automatic stock grants, 10b5-1 plan executions, or tax-related sales. DisclosureSignals uses a heuristic scoring model to filter out noise and surface only high-conviction transactions.

Our model considers position size relative to total holdings, transaction timing proximity to earnings, the insider's historical accuracy, and whether the transaction was discretionary or planned.