Insider buying is one of the few Wall Street signals with real academic backing. Executives sell stock for many reasons. They buy on the open market for only one.
They think the stock is going up.
The harder question is which insider purchases actually predict returns. Not every Form 4 is a green light. Many are pre-programmed plans with almost no information.
This article covers four things. What a real Form 4 buy looks like. Why cluster purchases beat lone-wolf trades. What the studies found. And which free tools track the signal.
Form 4 Filings and What Counts as a Real Buy
A Form 4 is the SEC filing every officer, director, and 10 percent shareholder must submit within two business days. It covers buys, sells, option exercises, gifts, and grants.
Most Form 4s are noise. A CFO selling to cover a tax bill is not bearish. A director receiving an annual grant is not bullish.
Open market purchases with personal cash
The cleanest signal is an open market purchase coded as transaction type P. The executive used personal funds and chose to add at the prevailing price. No obligation. No plan. No tax driver. This is the trade that matters.
10b5-1 plans and why they dilute the signal
Rule 10b5-1 lets insiders set up pre-scheduled trading plans. According to the SEC, these trades carry an affirmative defense against insider trading allegations. The trade was scheduled in advance.
The flip side is they carry almost no predictive content. If the 10b5-1 box is checked, treat the filing as background noise.
Cluster Buys vs Lone-Wolf Purchases
A single insider buying $50,000 of stock is interesting. Three insiders buying within the same two weeks is a different conversation.
Cluster buying happens when multiple officers and directors purchase shares in a short period. Per research summarized by Barchart, cluster purchases generate roughly double the excess return of solitary insider buys.
Why the cluster works
One executive can be wrong or signaling for optics. Five executives reaching the same decision in the same week are aggregating independent information. They are converging on a view the market disagrees with.
Berkshire and Occidental as a worked example
Berkshire Hathaway (BRK.B) has bought Occidental Petroleum shares across 12 separate purchases since 2019. Berkshire now owns roughly 27 percent of Occidental. That is a sustained cluster, not a single ticket.
Want to trade the names insiders are buying with conviction? Open a Gotrade account and get fractional access to stocks like OXY, JPM, and BAC.
Empirical Returns: Insider Buying Excess Return Studies
The academic literature here is unusually consistent. Three studies anchor the field.
Seyhun and the first systematic evidence
Michigan professor Nejat Seyhun published the most cited work. Using 1975 to 1981 transactions, he found abnormal returns of 4.3 percent over 300 days for firms with net insider buying. Net selling firms underperformed by 2.2 percent.
Seyhun also showed aggregate insider buying predicted up to 60 percent of one-year-ahead market returns.
Lakonishok and Lee on size and book-to-market
Lakonishok and Lee extended the work to 1995. They found the signal works mostly in smaller firms. The heaviest insider buying decile beat the lightest by roughly 5 percent over 12 months.
Cohen, Malloy, and Pomorski on routine versus opportunistic
The most useful refinement came from Cohen, Malloy, and Pomorski. They split insiders into routine traders and opportunistic traders. Routine trades carried zero predictive power. Opportunistic trades produced 82 basis points per month, roughly 10 percent annualized.
The takeaway is the same across all three. Insider buying works, but only after you filter the noise.
Tools and Free Trackers for Retail Investors
You do not need a terminal to track Form 4 activity. Three free tools cover the ground.
OpenInsider for raw filings
OpenInsider aggregates SEC Form 4 filings in real time. Filter by transaction type, insider role, and size. The cluster buy screen is the one to bookmark.
SEC EDGAR for the primary source
EDGAR is the SEC's own filing system. Slower than OpenInsider, but the canonical record. Pull important filings here rather than trusting an aggregator.
Finviz for daily scanning
Finviz offers a clean insider transactions feed. Pair it with OpenInsider when you want to drill into a specific name.
Conclusion
Insider buying is a real signal, but only when filtered. Open market purchases with personal funds. Multiple insiders converging in a short window. Opportunistic rather than routine traders.
Do not copy any single CEO buy on autopilot. Use insider buying as a confirming filter on names you already understand. Then trade the conviction on names like JPM and BAC through Gotrade, with fractional shares on US stocks.
FAQ
What is a Form 4 filing?
A Form 4 is the SEC disclosure officers, directors, and 10 percent holders must file within two business days of any company stock transaction.
Are 10b5-1 buys meaningful?
Pre-scheduled 10b5-1 trades carry an SEC affirmative defense but almost no predictive content, because the trade was decided before the insider had current information.
What's a cluster buy?
A cluster buy is multiple insiders at the same company purchasing shares in a short window, historically producing double the excess return of single buys.
Where can I track insider trades for free?
OpenInsider, SEC EDGAR, and Finviz cover real-time Form 4 filings, primary source documents, and quick daily scans.
Should retail investors copy CEO buys directly?
No, treat insider buying as a confirming filter on names you already understand, not as a standalone signal.
