What is SEC Form 4? Insider trades explained (2026)
You keep seeing the headline: "CEO buys $2 million of company stock." Then, two lines down, a filing called a Form 4. This is what that filing is, and how to read it yourself.
The short answer: a Form 4 is the public record of an insider trading their own company's shares. The useful part is a single letter on it that tells you whether the trade means anything.
What is SEC Form 4?
Form 4 is a filing that reports a change in an insider's ownership of a company's stock. Its official name is a "Statement of Changes in Beneficial Ownership," and every buy, sale, grant, or option exercise an insider makes shows up on one.
The point of it is disclosure. When someone close to a company trades its shares, the public has a right to know, because that person may be acting on information the rest of us do not have yet. The SEC requires the filing so the trade cannot stay private. The SEC's own investor bulletin lays out the same rules if you want the primary source.
Who has to file a Form 4?
Three groups, defined by Section 16 of the Exchange Act. A company's directors, its officers such as the CEO and CFO, and anyone holding more than 10% of a class of its stock all count as insiders.
The logic is simple. These are the people most likely to know something before the market does, so their trades are the ones worth disclosing. A junior employee buying shares files nothing; a board member doing the same files a Form 4 within days.
How fast does a Form 4 have to be filed?
Within two business days of the transaction. And the clock starts on the trade date, not the settlement date, so there is very little lag between an insider acting and you being able to see it.
That speed is what makes Form 4 useful. A company's financial statements arrive weeks after a quarter ends. A Form 4 arrives within 48 hours of the trade. It is the closest thing the market has to a live feed of what the people running a company are doing with their own money.
What do the transaction codes mean?
Every Form 4 transaction carries a one-letter code, and that code is the whole story. It tells you whether the insider made a decision or the company's payroll machinery just ran on schedule.
Here is the set you will actually run into:
| Code | What happened | Signal? |
|---|---|---|
P | Open-market purchase | Yes. Their own money, their own choice |
S | Sale | Maybe. Check for a 10b5-1 plan first |
A | Grant or award from the company | No. That is pay, not conviction |
M | Option exercise or conversion | No. Routine, often near expiry |
F | Shares withheld to cover tax | No. The company did it automatically |
G | Gift | No. No view on the price involved |
The reason P stands out is that it is the only one the insider had to choose. A grant lands in their account whether they want it or not. An option exercise is often just timing. But an open-market purchase means they looked at the price, decided it was cheap, and spent real money. That is the trade the guide to tracking insider buying is built around.
How do you read a Form 4?
You need four things from it, and you can ignore the rest of the form. Who filed it, the code, the size, and the footnotes.
Start with who filed it and their role, because a CEO buying carries more weight than an outside director. Then find the code in box 3. Then work out the size, shares times price, because a $4,000 buy is a gesture and a $2 million buy is a statement. Last, scan the footnotes: if there is a 10b5-1 note, the trade was set up months in advance under a plan, so it reflects no fresh opinion and you should discount it.
Why do Form 4s matter to investors?
Because of an asymmetry. Insiders sell for all sorts of reasons that have nothing to do with the stock, a house, a tax bill, diversification. But they buy on the open market for essentially one reason: they think it is going up.
That is why a purchase carries information a sale usually does not. And it is why most "insider selling" headlines mean very little, while a cluster of insiders buying at once is worth a closer look. Reacting to that in real time is what insider trading alerts are for.
Form 3, Form 4, and Form 5
Form 4 has two siblings, and it helps to know which is which. They are the same reporting regime at three different speeds.
Form 3 is the initial statement, filed within 10 days of becoming an insider. Form 4 reports each change within two business days. Form 5 is the annual catch-up for anything deferred or exempt, due within 45 days of the fiscal year end. If you want to see live activity, Form 4 is the only one that matters. The full set is described in the SEC's own Forms 3, 4 and 5 guide.
See real Form 4s right now
The fastest way to understand Form 4 is to read a few. Open the insider radar, which lists the biggest open-market insider buys across the market, live and free, and find one with a code P.
If you build software and want this data as JSON instead, the Form 4 API guide covers pulling it programmatically. Either way, once you can read the code, half the "insider trading" headlines you see will stop meaning anything, and the few that matter will stand out.
See today's biggest insider buys →
Edgrapi surfaces public SEC filings for research. It is not investment advice, and insider activity does not predict future returns.
Frequently asked questions
What is SEC Form 4?
SEC Form 4 is a filing titled Statement of Changes in Beneficial Ownership. A company insider submits it when their holding of the company's stock changes, so a buy, a sale, a grant, or an option exercise. It has to be filed within two business days of the trade and becomes public on SEC EDGAR, which is how the market learns what insiders are doing with their own shares.
Who has to file a Form 4?
Under Section 16 of the Exchange Act, a company's directors, its officers such as the CEO and CFO, and anyone who owns more than 10% of a class of its stock all count as insiders and must file. They report on Form 4 because they may know things the public does not, and the filing is how each of their trades in the company's stock is disclosed.
How quickly must a Form 4 be filed?
Within two business days of the transaction, and the clock starts on the trade date rather than the settlement date. That makes Form 4 close to a live feed of insider activity, far faster than a quarterly report. It is the reason a Form 4 can tell you an insider bought this week, not last quarter.
What do the Form 4 transaction codes mean?
P is an open-market purchase, S is a sale, A is a grant or award from the company, M is an option exercise, F is shares withheld to cover taxes, and G is a gift. P is the only code that means the insider chose to spend their own money on the stock, which is why it is treated as the real signal and the others are usually routine compensation.
What is the difference between Form 3, Form 4, and Form 5?
Form 3 is the initial statement, filed within 10 days of becoming an insider. Form 4 reports each change in ownership within two business days. Form 5 is an annual catch-up for deferred or exempt items, due within 45 days of the fiscal year end. Form 4 is the one that carries live trading activity.
Where can I find Form 4 filings?
They are public on SEC EDGAR the moment they are filed. You can search a single company there, or use a tracker that reads the whole feed and surfaces the notable trades. Edgrapi's free insider radar lists the biggest open-market insider buys across the market at edgrapi.com/insider, no account needed.