Insider filings, explained
Short, practical guides to reading SEC insider filings — what the forms and codes mean, which transactions carry signal, and why clustered insider buying is the pattern worth watching.
What is an insider cluster buy?
A cluster buy is two or more corporate insiders buying their own company's stock on the open market within days of each other. Here's why it's the strongest insider signal — and how to track it.
Form 4 transaction codes explained (P, S, A, M, F, G…)
Every SEC Form 4 transaction carries a one-letter code. P and S are the ones that matter for signal — here's the full table and what each code actually means.
How to read a Form 4 filing
A walkthrough of the SEC Form 4: the reporting owner, Table I vs Table II, transaction codes, prices, and footnotes — and the traps that mislead first-time readers.
What is a 10b5-1 trading plan?
10b5-1 plans let insiders schedule trades in advance to avoid insider-trading liability. Here's how they work and why plan trades carry less signal than discretionary buys.
Who counts as a corporate insider?
Officers, directors, and 10% owners are the 'Section 16 insiders' who must file Form 4s. Here's who's included, and why a CEO's buy means more than a passive fund's.
How fast must insiders report trades? (Form 4 deadlines)
Insiders must file a Form 4 within two business days of a trade. Here's the exact rule, the exceptions, and why the deadline makes real-time monitoring possible.
Form 3 vs Form 4 vs Form 5: what's the difference?
Form 3 declares initial ownership, Form 4 reports trades within two days, Form 5 catches up on exempt transactions annually. Which one carries signal?
Insider buying vs insider selling: why the signals aren't symmetric
Insiders sell for dozens of reasons but buy for one. The research and the intuition behind why purchases predict returns and sales mostly don't.
Insider buying vs share buybacks: which signal is stronger?
Buybacks spend shareholder money; insider buys spend the executive's own. Why personal purchases are the cleaner conviction signal, and what each is good for.
What is an open-market purchase (Form 4 code P)?
An open-market purchase is an insider buying company stock on the exchange with personal cash — transaction code P on Form 4. Why it's the only routine filing event with real signal.
Why insider buying matters most in small-caps
The information gap between insiders and the market is widest in small and micro-cap stocks — no analyst coverage, thin liquidity, and binary outcomes. Here's the logic and the evidence.
What is SEC EDGAR (and how insider filings get there)?
EDGAR is the SEC's public filing system — every Form 4 appears there within seconds of acceptance. How the pipeline works and how to read filings at the source.