// guides
SEC Filings & Insider Trading — Explained
Updated 2026-06-10. Developer-focused write-ups on the SEC filings that matter for insider trading analysis — what they mean, how to read them, and how to access them programmatically.
SEC Form 4 explained
Who files, transaction codes, the 2-day rule, and how to read insider filings.
SEC Form 144 explained
Notice of proposed sale — thresholds, the 90-day window, and how it leads Form 4.
13F-HR filings explained
Institutional holdings — the $100M threshold, the 45-day lag, and CUSIP mapping.
Cluster buy signals
Why multiple insiders buying together is the strongest insider signal.
10b5-1 trading plans
Why pre-scheduled insider trades carry less signal, and how to filter them out.