By the InsiderAlpha research team · Updated Jul 16, 2026 · Sourced from SEC EDGAR filings
An insider purchase is one of the most-watched data points in fundamental investing — it is the rare case where someone with an information advantage is required to tell you, in public, that they just bet their own money on the stock. But the raw Form 4 feed is noisy: it mixes equity grants, tax-withholding sales, and pre-scheduled plan trades in with the genuine conviction buys. Here is how to separate signal from noise.
Purchases by the CEO, CFO, or Chairman have historically outperformed buys by less-informed insiders — the CFO in particular tends to know the numbers first. 10% owners such as activist funds also carry weight, because they make large, research-driven directional bets. InsiderAlpha weights officer buys (1.5×), 10% owner buys (1.6×), and director buys (1.2×) accordingly.
A $50,000 purchase from an executive earning $20M a year is a rounding error. The same $50,000 from a small-cap director earning $200K is a real statement of conviction. Always read the dollar value of a buy against the insider's pay and existing stake, not in isolation.
When two or more insiders buy in the same short window, the signal is far stronger than any single purchase. Cluster buys frequently precede positive earnings surprises and strategic announcements because they suggest the insiders are reacting to the same shared, non-public read on the business.
Pre-scheduled Rule 10b5-1 trades are calendar-based, not opportunistic — the insider set them up months in advance. InsiderAlpha detects 10b5-1 markers in Form 4 footnotes and flags them so they don't pollute your buy signal.
The edge decays fast. A 24-hour-old buy in a liquid mid-cap is actionable; a 30-day-old buy in a thinly-traded micro-cap is not. We apply a recency bonus that decays over 48 hours and require real liquidity (50-day average volume ≥ 100,000 shares) before a name reaches the plan.
The highest-conviction setup combines all five: a large, open-market purchase (code P), by a top officer or 10% owner, that is meaningful relative to their pay, made alongside other insiders, in a liquid stock, within the last day or two — and not flagged as a 10b5-1 plan trade. That is exactly the combination InsiderAlpha's score is built to surface.
Equity awards (code A), option exercises paired with same-day sales (M + S), and tax-withholding dispositions (F) are compensation mechanics, not signals. Routine, scheduled selling is also weak — insiders sell for diversification, taxes, and liquidity all the time.
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