Intro to Insider Buying

An insider is a person with a close view of a company's business — typically its officers (CEOs, CFOs and other senior executives), members of the board of directors, and anyone who owns more than 10% of the company's shares.

Insider buying is when one of these people buys their own company's stock on the open market — the same exchange any ordinary investor uses, with their own money. Because insiders have a duty to be transparent, every such trade must be reported to the U.S. Securities and Exchange Commission (SEC) on a Form 4 within two business days. Those filings are public, which is what makes this activity possible to track at all.

Rather than take the premise on trust, we tested it on our own filing archive. The rules are deliberately crude — no scoring model, no discretion — so the result reflects the raw signal: each week, buy the ten companies with the most insider buying behind them, equally weighted, and hold for a week.

The classic framing comes from investor Peter Lynch: insiders may sell their shares for any number of reasons, but they generally buy for only one — they expect the stock to be worth more later. Selling can be explained by taxes, diversification, a house, a divorce or simple cash needs. A purchase puts an insider's own money at risk in the one stock they understand best.

The important distinction is that the meaningful signal comes from open-market buys — discretionary purchases an insider chose to make. It does not come from shares received as compensation, such as stock grants or exercised options, which arrive on a schedule regardless of how the insider feels about the price.

Not all insider buys are equal. A few characteristics tend to make a purchase more meaningful:

Insider sells are noisy. Much insider selling is automatic and planned in advance — for example through pre-arranged trading plans — or simply reflects an executive turning a slice of their compensation into cash for reasons that have nothing to do with the company's prospects. A sale tells you very little on its own.

Insider buys are cleaner. An insider voluntarily adding to their position, with their own after-tax money, is choosing to increase their exposure to a stock they could just as easily leave alone. That is why open-market buying is treated as the signal, and selling mostly as background noise.

We turn live SEC Form 4 filings into something you can actually scan. A good starting point:

• •Insider Score rankings — every company sorted by the strength of its current insider buying, strongest signals first.
• •Stock lists — curated groupings such as cluster buys and CEO buying, so you can browse by theme rather than one ticker at a time.
• •Per-company Form 4 activity — open any company to see the underlying filings: who bought, what role they hold, how many shares, and how their stake changed.