Every insider trade on this site comes from one document: SEC Form 4. If you've ever clicked through to the original filing on the SEC's website, you know it isn't friendly. It's a dense government form full of codes and footnotes.
The good news is that you only need about five things from it. Here's what to look at, in the order we look at them.
First, what is a Form 4?
When an officer, a director, or anyone owning more than 10% of a company buys or sells its stock, they have to tell the SEC within two business days. Form 4 is how they do it. The filings are public and free on the SEC's EDGAR website, which is why sites like this one can exist.
Two business days is quick. It means you're seeing insider trades almost as they happen, not months later. That's very different from, for example, Congress stock disclosures, which can come up to 45 days late.
The five things that matter
1. Who filed it (Box 1 and Box 5)
Box 1 is the person's name. Box 5 tells you their relationship to the company: Director, Officer (with a title like CEO or CFO), or 10% Owner.
This matters more than people think. A CEO or CFO sees the company's numbers before anyone else does. A 10% owner is often an investment fund, which buys and sells for its own reasons. The same $500,000 purchase can mean very different things depending on who made it.
2. The transaction code (Table I, column 3)
This is the most important column and the most often misread. The code is a single letter:
| Code | What it means | Does it tell you much? |
|---|---|---|
| P | Open-market purchase. They bought shares with their own money. | Yes. This is the one to watch. |
| S | Open-market sale | Sometimes (see below) |
| A | Grant or award from the company | No. It's part of their pay. |
| M | Option exercise | Rarely |
| F | Shares withheld to pay taxes | No |
| G | Gift | No |
Most Form 4s you'll see are A, M or F: routine pay-related paperwork. They're why headlines like "CEO acquires 50,000 shares!" are often meaningless. Only code P is someone choosing to put cash into the stock. That's why this site counts only P and S trades and leaves the rest out.
3. Shares and price (Table I, column 4)
Column 4 has three parts: the number of shares, an "A" (acquired) or "D" (disposed), and the price per share. Multiply shares by price and you have the dollar size of the trade.
Size is relative. A $50,000 buy from a director at a small company might be a big part of their savings. The same amount from a billionaire founder is pocket change.
4. Shares owned afterward (Table I, column 5)
This tells you how much they hold after the trade, and it's a useful sense check. If someone buys 10,000 shares and now owns 15,000, they just tripled their stake. That says a lot more than buying 10,000 shares on top of 2 million.
5. The footnotes, especially "10b5-1"
Scroll to the bottom. If a sale was made under a Rule 10b5-1 plan, the footnotes (or a checkbox at the top on newer forms) will say so. A 10b5-1 plan means the sale was scheduled months in advance, often for taxes or diversification. Planned sales say much less than unplanned ones. We mark them with a "Plan" tag on this site.
A real example from this week
Here's one from this week's filings, so you can see the pieces together:
- Who: Rubens Aguiar Alvarez, Director at Bank Bradesco ($BBD)
- Code: P, an open-market purchase
- How much: 1,698,000 shares at about $17.37, roughly $29.5M
- Owned afterward: 3,690,000 shares, so this purchase raised their stake by about 85%
- Filed: Oct 9, 2026, for a trade on Sep 1, 2026
On its own, that's one person's decision. It gets more interesting when other insiders at the same company buy too. That's what we call a cluster buy.
The shortcut
You don't need to read every Form 4 yourself. Every stock page on this site pulls these same fields out of the filings: who, role, code, shares, price and shares owned afterward, with a link back to the original filing on the SEC's site. Use the original when you want to double-check something, and the stock pages for everything else.
If you want to go a level deeper:
- Form 4 basics, our longer guide
- Why planned 10b5-1 sales say less
- What happened 90 days after insiders bought together, our research on whether cluster buys work