Insider buying vs share buybacks: which signal is stronger?

Both look like "the company thinks its stock is cheap." They are not the same signal, and the difference comes down to whose money is at risk.

Buybacks: corporate money, mixed motives

A buyback is a board-authorized use of shareholder cash. Some buybacks are genuine valuation calls; many exist to offset dilution from stock compensation, hit EPS targets that drive bonus formulas, or signal without any executive taking personal risk. Announced authorizations often go partly unused. An executive can preside over a billion-dollar buyback while personally selling every vested share — and that combination is common.

Insider buys: personal money, one motive

An open-market purchase (Form 4, code P) is the executive's own after-tax cash adding to an already concentrated position. There's no EPS arithmetic and no dilution management — just a view on the price. That's why purchases are the asymmetric signal in the filing data.

The best case: both at once

When a company is buying back stock and multiple insiders are buying personally — a cluster buy on top of an active repurchase program — corporate and personal conviction are pointing the same direction. The cluster is the part we detect automatically; see which stocks show one now.