Insider buying: what it signals when executives buy (and what it does not)

"Insider buying" is the purchase of a company’s shares by its own executives and directors. The logic is intuitive: no one knows a company better than those who run it, and if they invest their own money in it, it could be a sign of confidence in the future of the business.

Why it can be relevant

There is a classic saying: executives sell shares for many reasons (to diversify, to pay taxes, to buy a house), but they only buy for one: they think the stock will go up. That is why purchases tend to carry more informational value than sales.

What makes a signal strong

• Relative size: a meaningful purchase relative to the executive’s wealth weighs more than a token one.
• Who buys: purchases by the CEO or CFO are usually watched more closely.
• Concentration: several purchases by different insiders at once strengthen the signal.
• Real purchase vs. exercising options: buying on the open market says more than exercising already-granted options.

Its limitations

Insider buying is not a crystal ball. Executives get it wrong too, and a purchase guarantees nothing about the future price. It is a supporting signal, not an investment thesis on its own: it makes sense when it accompanies solid fundamentals, not when it replaces them.