Are Insider Buys Bullish? What the Research Says

Short answer: certain insider buys are genuinely bullish, and the effect is one of the most durable anomalies in finance - but the average insider trade, taken indiscriminately, is much weaker than headlines suggest. The edge lives in which buys you pay attention to.

The case for "yes"

Insiders trade their own stock with a structural information advantage, and decades of research show they exploit it on the buy side. Lakonishok & Lee (2001) found insider purchases predict positive future returns, especially in small-cap stocks. Cohen, Malloy & Pomorski (2012) showed that filtering for "opportunistic" insiders - those who trade irregularly, not on a fixed schedule - lifts the predictive abnormal return to roughly 8% a year. Buying is also "cleaner" than selling: there is essentially one reason an insider buys (they expect the stock to rise), versus many reasons they sell.

When an insider buy is bullish

• Open-market purchases (code P) made with the insider's own cash - not grants or option exercises.
• Senior, well-informed insiders - CEO, CFO, Chairman, or a 10% owner.
• Size that is meaningful relative to the insider's pay and existing holdings.
• Clustered buying by several insiders at once.
• Opportunistic timing - irregular, not a calendar plan.

When it is not a signal

• Equity awards (A) and option exercises (M) - these are compensation, not conviction.
• Tiny, symbolic buys meant to signal confidence to the market without real capital at risk.
• Pre-scheduled 10b5-1 purchases - the timing isn't the insider's choice.
• Illiquid micro-caps where you can't trade the signal at a sane price.

Important caveats

Insiders are not market timers - they are often early, buying into declines that continue for a while before turning. The effect is a tendency measured across many trades over months, not a guarantee on any single name. And selling is genuinely ambiguous: insiders sell for taxes, diversification, and houses all the time, so "insider selling" is a far weaker signal than insider buying.

The bottom line

Insider buying is bullish when you filter it properly: open-market, senior, sizeable, clustered, opportunistic, and liquid. That filtering is exactly what InsiderAlpha's scoring automates.

See this week's highest-conviction buys → · The full buy-signal guide →

This article is informational and is not investment advice.