Form 4 is the SEC report that a public company's officers, directors and 10%-plus shareholders file within two business days of buying or selling the company's stock. To read one, check who traded, the transaction code (P for open-market purchase, S for sale), the price, the shares owned afterward, and whether the trade was made under a pre-set 10b5-1 plan.
You saw a headline that a CEO "dumped" shares, or a screener flagged "cluster insider buying" at a company you own. Before you react, you want to know what the filing actually says. Most Form 4s are routine paperwork, and the few that carry information look different from the rest once you know the codes.
What is a Form 4?
Form 4 discloses a change in an insider's ownership of company securities. According to the SEC's investor bulletin on Forms 3, 4 and 5, officers, directors and holders of more than 10% of any class of a company's securities must report their purchases, sales and holdings. Form 4 shows the amount bought or sold and the price per share, and covers both common stock and derivatives such as options and warrants.
How fast must insiders file a Form 4?
A Form 4 is due within two business days after the transaction, per the SEC bulletin. That speed is what makes it useful: you see insider activity days after it happens, not months.
| Form | When it is filed | What it shows |
|---|---|---|
| Form 3 | Within 10 days of becoming an insider | Initial holdings |
| Form 4 | Within 2 business days of a transaction | Each change in ownership |
| Form 5 | Within 45 days after fiscal year end, if needed | Transactions not reported earlier |
Where do you find Form 4 filings?
All Forms 3, 4 and 5 are free on EDGAR. Search the company in EDGAR full-text search and filter the form type to 4, or open the company's filing list and look for insider filings. Our guide to using SEC EDGAR shows the steps. Many free finance sites also aggregate the same data, but the filing itself is the primary source.
How do you read a Form 4 line by line?
A Form 4 has a header and two tables. Read them in this order.
Box 1 and Box 5: who filed and their role
The reporting person's name and relationship to the company: director, officer (with title), 10% owner or other. A CEO or CFO trade usually says more than a trade by a large outside fund.
Table I: non-derivative securities
Common stock transactions. Columns show the date, the transaction code, the number of shares, whether they were acquired (A) or disposed of (D), the price, and the shares owned after the transaction.
Table II: derivative securities
Options, warrants, restricted stock units and convertibles. Option exercises usually appear here and in Table I at the same time.
Footnotes
Often the most useful part. Footnotes explain weighted-average prices, trusts, gifts and whether a sale was made to cover taxes.
The 10b5-1 checkbox
Since April 1, 2023, insiders must tick a box when a trade was intended to satisfy Rule 10b5-1, and disclose the date the trading plan was adopted, according to the SEC's 2022 announcement of the amendments. A 10b5-1 plan sets trades in advance, so a sale under an old plan says little about the insider's current view.
What do the Form 4 transaction codes mean?
The transaction code is the single most important column. These are the common codes listed in the SEC bulletin:
| Code | Meaning | How much it usually tells you |
|---|---|---|
| P | Open-market or private purchase | Often the most informative |
| S | Open-market or private sale | Depends on context |
| A | Grant or award from the company | Usually compensation |
| M | Exercise or conversion of a derivative | Usually routine |
| F | Shares withheld to pay exercise price or taxes | Usually routine |
| G | Gift | Rarely about the outlook |
| D | Sale or transfer back to the company | Varies |
| J | Other, explained in a footnote | Read the footnote |
Which insider trades matter most?
Purchases with personal money tend to say more than sales. The SEC bulletin notes that insiders may sell for many reasons, including liquidity and diversification. Buying in the open market has fewer innocent explanations.
Signals worth a closer look
- Code P by a CEO or CFO, especially a meaningful amount relative to their holdings.
- Several insiders buying in the same few weeks.
- A sale that is not under a 10b5-1 plan and is large relative to what the person owns.
- A pattern change, such as an insider who has sold every quarter for years suddenly stopping, or the reverse.
Usually routine
- Code A grants, M exercises and F tax withholding.
- Small scheduled sales under a 10b5-1 plan adopted long ago.
- Gifts to family trusts or charities.
A worked example
Suppose a CFO's Form 4 shows: code S, 20,000 shares sold at $50, 180,000 shares owned afterward, 10b5-1 box checked with a plan adopted 14 months earlier. That is a $1 million sale, about 10% of the CFO's stake, set up more than a year before. On its own, it says little.
Now suppose a director's Form 4 shows code P, 10,000 shares bought at $48, holdings rising from 15,000 to 25,000, with no 10b5-1 box. That is roughly $480,000 of personal money and a 67% increase in their stake. That filing deserves a look at the latest 10-Q to see what the director might be seeing.
What are the limits of insider data?
Insider trades are one input, not a signal to buy or sell. Insiders can be wrong, purchases can be small gestures, and some companies have few insiders who trade at all. Pair the filings with the business fundamentals, such as the P/E ratio and the company's own disclosures.
Frequently asked questions
Is insider buying and selling legal?
Yes, when insiders trade on public information, follow company trading windows and report the trade on Form 4. Illegal insider trading means trading on material nonpublic information.
What is the difference between Form 4 and Form 144?
Form 4 reports a completed change in ownership. Form 144 is a notice of a proposed sale of restricted or control securities, so it can appear before the trade.
Does a Form 4 sale mean the stock will fall?
Not necessarily. The SEC notes that insiders sell for many reasons, including diversification and personal liquidity. Sales under long-standing 10b5-1 plans are especially weak signals.
Are small insider purchases always reported right away?
Not always. The SEC bulletin notes some transactions, such as certain small purchases under $10,000 in six months, can be reported later on Form 5.
Related: How to read a 10-K annual report · What is an 8-K filing? · How do you use SEC EDGAR?