When a company's executives or directors buy or sell its stock, they have to tell the public. Those filings are free, fast and widely watched. They can also be badly misread. Here's how to read them properly.
What a Form 4 is
In the US, company insiders (officers, directors, and anyone owning more than 10% of a class of the company's shares) must report changes in their holdings to the SEC on Form 4. The filing is due within two business days of the trade, and it's public on the SEC's EDGAR system as soon as it's filed.
A Form 4 is a record, not an accusation. "Insider trading" in the news usually means illegal trading on secret information. A Form 4 is the opposite: a legal trade, reported publicly.
The parts that matter
A Form 4 is a dense table, but you only need a few columns:
- Who filed it, and their role (CEO, CFO, director, 10% owner).
- The transaction code, which tells you what kind of transaction it was. This is the most important column.
- Shares and price, so you can work out the dollar value.
- Shares owned after the transaction, so you can see how big the trade was compared with what they hold.
- Footnotes, which often say whether the trade was pre-planned.
Transaction codes: the column that changes everything
The same "shares went down" can mean completely different things depending on the code. The common ones:
- P: an open-market or private purchase. The insider spent their own money on the stock.
- S: an open-market or private sale.
- M: an option exercise (turning stock options into shares).
- A: a grant or award from the company, such as stock given as pay.
- F: shares withheld to pay tax when stock pay vests.
- G: a gift.
Codes A, F and M are mostly mechanics of how executives are paid. They tell you very little about what the insider thinks of the stock.
Why buying usually tells you more than selling
Insiders sell for many reasons that have nothing to do with the company: buying a house, paying tax, diversifying, a planned sale every quarter. Most executives are paid in stock, so they are natural sellers.
An insider buying with their own cash, at the market price, has only one obvious reason: they think the shares are worth more. That's why investors who follow insider trades tend to pay more attention to open-market purchases (code P) than to sales.
Pre-planned trades (Rule 10b5-1)
Many sales are made under a 10b5-1 plan: instructions set up in advance, while the insider had no inside information, that trigger sales on a schedule. Form 4 has a checkbox for these, and the footnotes usually mention the plan. A planned sale says less about the insider's current view than a sudden, unplanned one.
Patterns worth paying attention to
- Clusters. Several different insiders buying within a few days or weeks is rarer, and usually more meaningful, than one person's trade.
- Size compared with their holding. A director adding 50% to their stake means more than a CEO selling 2% of theirs.
- Who it is. CEOs and CFOs see the whole business. A buy by the CFO after a falling share price stands out.
- Timing. A purchase soon after bad news, or before results, shows conviction (insiders can't trade during blackout windows around earnings, so a trade's timing is constrained).
And patterns that look dramatic but often aren't: a big headline sale under a 10b5-1 plan, tax withholding on vesting (code F), and option exercises followed by immediate sales.
Limits to keep in mind
Insider trades are one piece of evidence. Insiders can be wrong, especially about the wider market. Some buy to show confidence publicly. And for a large, heavily traded company, insider purchases are often tiny compared with daily volume. Use them alongside the company's results, valuation and everything else, not instead of them.
How Ticker Council uses insider trades
The Insider Trades seat on Ticker Council reads recent Form 4 filings for the stock you run. It follows the rules above: clusters of buys count more than single buys, C-suite more than directors, open-market purchases far more than option exercises, size is judged against the insider's existing holding, and routine planned sales count for almost nothing. When nothing rises above the noise, it stays close to 50/50 and says so. Insiders tend to trade on a view of months or years, so the seat's signal is strongest for the 3-month and 1-year calls. Its vote is one of twelve, debated against the other seats' evidence.
Not financial advice: this article explains how to read public filings. It doesn't tell you what to buy or sell.
Questions
What is an SEC Form 4?
It's the form company insiders (officers, directors and owners of more than 10% of a class of shares) use to report buying or selling the company's stock. It must be filed within two business days of the trade and is public on the SEC's EDGAR website.
Is insider buying a good sign?
Often it's one of the more meaningful signals in public filings, especially open-market purchases (code P) by several insiders at once. But insiders can be wrong, so treat it as one piece of evidence, not a reason on its own.
Why do insiders sell so much stock?
Because they're usually paid in stock, and they sell for ordinary reasons: taxes, diversifying, buying a home, or a pre-arranged schedule under a 10b5-1 plan. A single sale rarely says much about the company.
Where can I see insider trades for free?
On the SEC's EDGAR system: search for the company and open its Form 4 filings. Many websites also collect and summarise them.