Every signal starts with an SEC Form 4 filing — disclosure required within two business days of an insider buying or selling their own company's stock. We only look at open-market purchases, never option exercises, grants, or automatic sales.
Each qualifying purchase is scored on: how much it grows the insider's existing stake, whether a CEO or CFO was involved, whether multiple insiders bought together, price relative to the 52-week range, and market capitalization. Purchases that already ran too far past the insider's own entry price are excluded.