Insider transactions and Form 4
Who counts as an insider, why Form 4 is filed within two business days, why selling says less than buying, and what the Insiders panel shows.
Key points
- Officers, directors and holders of more than 10% of a company must report transactions in its shares on SEC Form 4.
- Form 4 is due within two business days, which makes it by far the most timely of the ownership disclosures.
- Buying carries more information than selling, because insiders sell for many reasons and buy for one.
Who counts as an insider
The SEC defines an insider as an officer or director of a company, or anyone holding more than 10% of a class of its registered shares. The definition is about position rather than about knowledge, so it captures people who may have no involvement in day-to-day decisions and misses people who do.
Insiders file three forms. Form 3 is the initial statement of holdings when somebody becomes an insider. Form 4 reports a change in those holdings and is the one that matters day to day. Form 5 covers small or exempt transactions not reported during the year.
Every transaction on the Insiders panel of a company page comes from these filings, showing the transaction date, the person, their relationship to the company, and the number of shares, with disposals carried as negative so a column of transactions sums to a net position change.
Two business days, not forty-five
Form 4 is due within two business days of the transaction. That deadline is what separates it from the other ownership disclosures on this site, and it is the reason insider data is worth watching in a way that quarterly fund filings are not.
The table sets the three regimes beside each other. The same question, who bought what, is answered on three completely different clocks.
The practical consequence is that an insider purchase is close to current information, while a 13F position may have been sold before it was published. None of the three is a recommendation, but only one of them describes something that happened this week.
| Filing | Who files it | Deadline | Age when published |
|---|---|---|---|
| Form 4 | Officers, directors, 10% holders | 2 business days | Days |
| STOCK Act disclosure | Members of Congress | 45 days | Up to about six weeks |
| Form 13F | Managers of over $100m in US equities | 45 days after quarter end | Up to about four and a half months |
Why buying says more than selling
An insider sale has many possible explanations that have nothing to do with the company: a tax bill, a house, a divorce, diversifying a position that has grown to dominate a personal balance sheet, or a scheduled trading plan set up months earlier. Executives are also paid substantially in shares, so selling is how compensation becomes money.
A purchase with the insider's own money has fewer explanations. That asymmetry is the whole of the conventional wisdom that insider buying is the more informative signal, and it is a statement about the range of motives rather than a claim that purchases predict returns.
Scale matters more than the fact of a transaction. A director buying a few thousand dollars of shares after a fall is a gesture; one buying a year of salary is committing to a view. The share counts on the panel are what make that distinction visible.
Planned sales and what they look like
Executives commonly sell under a pre-arranged plan adopted while they had no material non-public information, which sets the timing and size of future sales in advance. Sales made under such a plan are still reported on Form 4, and they can appear at moments that look significant while having been scheduled months earlier.
A steady, evenly spaced series of sales of similar size is the usual signature of one. A single large sale out of an established pattern is the one worth reading.
The same logic applies to purchases that are not really purchases: option exercises and vesting events increase an insider's holding without expressing a view about the price.
What insider data does not tell you
It does not say why. The filing records a transaction, a date and a quantity, and no filing carries a reason.
It does not cover everybody who might act on information. The definition is positional, so an employee two levels below an officer files nothing.
And it is not evidence of wrongdoing. Trading by insiders is legal and routine when it is disclosed and not based on material non-public information. A well-timed transaction is a question rather than an answer, and across thousands of filings a year some will look remarkable through chance alone.
Common mistakes
Reading a sale as a signal without checking whether it is one of a regular series.
Counting an option exercise or a vesting event as a purchase.
Weighing transactions by count rather than by size, which treats a token purchase and a career-sized one as the same event.
Looking at one insider rather than the pattern. Several insiders buying independently in the same window is a different observation from one doing so.
Expecting timeliness from the other disclosures. Congressional filings and 13Fs answer similar questions on a scale of weeks and months.
Educational information about how these figures are constructed. Not investment advice, and not a recommendation to buy or sell any security.
