Insider Buying and Selling: What the Signal Really Means
Updated: 5 hours ago
Insider buying means a director or executive has bought their own company's shares on the open market with their own money. It is a meaningful signal of confidence, especially when several insiders buy after a price fall. Insider selling tells you far less, because executives sell for many ordinary reasons such as taxes, diversification and buying a house. Treat insider buying as a useful confirmation in a business you have already researched, never as a reason to buy on its own.
This article explains what counts as an insider trade, which trades matter, where to find the filings in the US, Canada and Europe, and how the signal fits into the Five Criteria.
Where this fits: insider ownership and insider buying are part of the "skin in the game" test in Criterion 3 (aligned management). For the full management test, see the hub, how to evaluate management before you invest.
What Is an Insider Trade?
In securities law, an insider is usually a director, a senior officer, or a large shareholder of a listed company. When they buy or sell the company's shares, they must report the trade publicly within a short time.
This is legal insider trading. It is different from illegal insider trading, which means trading on material information the public does not have. Insiders are generally barred from trading during "blackout periods" before results are released, and while they hold undisclosed price-sensitive information.
Not every reported transaction is equally informative. It helps to sort them into types.
Transaction type | What it is | Signal strength |
Open-market purchase | Insider buys shares with personal cash | Strong |
Open-market sale | Insider sells shares | Weak on its own |
Option exercise | Insider converts options into shares | Weak |
Share grant or vesting | Shares received as pay | None |
Pre-planned sale | Sale under a trading plan set up in advance | Very weak |
Why Insider Buying Matters
Peter Lynch put it neatly in One Up on Wall Street: insiders might sell their shares for any number of reasons, but they buy them for only one, which is that they think the price will rise.
The logic is sound. Most executive shareholdings arrive as part of their pay, at little or no personal cost. An open-market purchase is different. The insider takes cash from their own account and buys at the same price you would pay. Nobody forces them to do it.
Philip Fisher also valued management's ownership of shares as a sign that its interests lined up with other owners'. Insider buying goes one step further: it is ownership chosen deliberately, with personal money.
The patterns that carry the most weight
Cluster buying. Several insiders, such as the CEO, CFO and a director, buy within a few weeks of each other. Each has different information and personal circumstances, so agreement is more meaningful than one purchase.
Large purchases relative to the insider's pay. A CEO who buys shares worth several times their annual salary is making a serious bet. A token purchase worth a few days' pay may be for show.
Buying after a price fall. When a stock has fallen sharply and insiders step in, they are signalling that they think the market has overreacted.
Buying by the people closest to the numbers. Purchases by the CFO or long-serving directors can carry extra weight.
Academic studies have generally found that insider purchases carry more useful information than insider sales. Even so, the signal is imperfect. Insiders can be wrong, too optimistic about their own company, or early by years.
Why Insider Selling Tells You Less
Most insider selling has nothing to do with the insider's view of the business. Executives receive much of their pay in shares. To pay taxes, diversify, fund a house purchase or pay for education, they must sell some. That is ordinary financial planning.
Many insiders also sell under pre-arranged trading plans. In the US these are known as Rule 10b5-1 plans. The insider sets the sales schedule in advance, so a sale that happens to follow bad news may have been decided months earlier.
When selling does deserve attention
Several senior insiders selling large amounts at once, outside their usual pattern or plans.
Selling most of a stake. An executive who cuts their holding from a large to a token amount has changed their skin in the game, whatever the reason.
Buying then quickly selling. An insider who buys and then sells within months suggests something changed.
Selling alongside other warning signs, such as a sudden CFO departure, a change of auditor or a delayed report.
Where to Find Insider Filings
The rules differ by country, but the data is public almost everywhere. In general terms:
United States. Directors, officers and holders of more than 10% report trades on Form 4, generally within two business days. Filings are free on the SEC's EDGAR database. Form 4 uses letter codes: "P" is an open-market purchase and "S" is a sale; grants and option exercises use other codes.
Canada. Insiders of listed companies report trades on SEDI, the System for Electronic Disclosure by Insiders, generally within five calendar days.
European Union and United Kingdom. Under market abuse rules, "persons discharging managerial responsibilities" and people closely associated with them must notify trades above a threshold. The company then publishes the notification, usually within a few business days. Look for "managers' transactions" or "PDMR" announcements on the company's investor relations site or the stock exchange news service.
Free aggregator websites also collect insider trades and let you filter for open-market purchases only. Always check the underlying filing to confirm the transaction type.
A note from the investor-relations side
Having worked in investor relations at Nasdaq Copenhagen-listed companies, I have seen how seriously companies treat insider-trade disclosure, and how carefully insiders are restricted around results. Two practical points follow. First, insider purchases often cluster just after results are published, when trading windows open, so timing alone is not a signal. Second, the size and the person matter far more than the headline. Read the actual announcement.
A Worked Example: Reading Three Situations
Company A, a business you have already researched, has fallen 35% after a weak quarter.
Situation | What happened | How to read it |
1 | CEO, CFO and two directors buy shares worth several times their salaries within a month | Strong confirming signal |
2 | CEO sells 5% of holding under a pre-planned trading plan | Little information |
3 | CFO resigns and three executives sell most of their stakes | Serious warning, investigate |
In situation 1, the insiders are telling you they think the fall is overdone. That is worth noting, but you still need to check the business, the balance sheet and the price. In situation 2, nothing much has changed. In situation 3, the combination is what matters, not any single sale.
How We Use This in the Five Criteria
Insider activity is part of Criterion 3, aligned management. Our house default thresholds are:
Meaningful insider ownership. For a smaller company, founders or executives owning several percent is a strong sign. For a very large company, look at the value of the stake compared with the executive's annual pay.
Share count flat or falling over five years. Insiders owning a lot means little if the share count keeps rising. See stock dilution explained.
Insider buying as confirmation, not a trigger. A cluster of open-market purchases can raise conviction in a company that already passes the other criteria. It never overrides a failed criterion.
Remember the order of the Five Criteria. Insider buying cannot turn a poor business into a good one, or make an expensive stock cheap. It also cannot replace your own estimate of value; see margin of safety explained.
Common Mistakes
Buying just because insiders bought. Insiders can be wrong, and a small purchase can be a public-relations gesture.
Panicking at every insider sale. Most sales are routine.
Counting option exercises and grants as buying. Only open-market purchases with personal cash count.
Ignoring the size. A purchase worth a few days' pay tells you little.
Forgetting the rest of the research. Insider data is one input among many.
Frequently Asked Questions
Is insider buying a good sign? Generally yes, especially when several insiders buy meaningful amounts on the open market after a price decline. It is a confirmation, not proof.
Is insider selling a bad sign? Usually not on its own. Insiders sell for taxes, diversification and personal needs. Large, simultaneous sales by several senior people, or sales alongside other warning signs, deserve a closer look.
Where can I see insider trades for free? On SEC EDGAR (Form 4) for US companies, on SEDI for Canadian companies, and in company announcements of managers' transactions in the EU and UK. Free aggregator sites also compile them.
Is it legal for insiders to trade their own company's stock? Yes, when they follow the rules: trading outside blackout periods, without undisclosed material information, and reporting each trade on time.
Your Next Step
Look up the insider transactions for one company you own over the last two years, filtering for open-market purchases only. Then compare what you find with the share count and management's pay structure, using the hub on how to evaluate management. Score the company on all five criteria with the Five Criteria Checklist.
About the author: Cameron Hayes is a senior investor relations and finance professional who has worked in IR at Nasdaq Copenhagen-listed companies including Nilfisk and Maersk Drilling. He holds an MSc from Copenhagen Business School and a BCom from the University of Ottawa, and founded Gingernomics to teach individual investors the Five Criteria framework. More about Gingernomics.
The content on Gingernomics is for educational and informational purposes only and does not constitute financial advice. Always do your own research and consult a licensed financial advisor before making any investment decisions. Past performance is not indicative of future results.
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