How to read an SEC Form 4 filing

August 14, 2026·10 min read

A Form 4 is one page of boxes, and almost all of its meaning sits in a single letter. Get that letter wrong and a routine tax withholding reads as an executive dumping stock, or a compensation grant reads as a vote of confidence. This is what each field on the form actually says, quoted from the form itself rather than from somebody’s summary of it.

What a Form 4 is

Form 4 is the “Statement of Changes in Beneficial Ownership”, filed under Section 16(a) of the Securities Exchange Act of 1934. Three kinds of people file it: directors, officers, and holders of more than ten percent of a class of the company’s registered equity. The form asks the filer to check which of those they are, and offers a fourth option — “Other” — which General Instruction 1(d) reserves for anyone reporting for a reason that does not fit the first three.

It is filed electronically through EDGAR, and it is public the moment it lands. There is no subscription and no request process. General Instruction 2(a) requires electronic filing except for filers who have obtained a hardship exception, which is why a paper Form 4 is now close to a curiosity.

The deadline, exactly as written

General Instruction 1(a) is one sentence and worth quoting in full, because paraphrases lose the part that matters:

“This Form must be filed before the end of the second business day following the day on which a transaction resulting in a change in beneficial ownership has been executed.”

Two business days, counted from execution, not from when anyone got around to noticing. That is the single most important structural fact about insider data: it is genuinely close to current. A Form 4 filed on a Wednesday describes something that happened on Monday.

The contrast worth holding in your head is congressional disclosure. Under the STOCK Act, a member of Congress reports within 30 days of being notified of a trade and in no case later than 45 days after it. Same idea, same kind of public filing, an order of magnitude apart in freshness. If you follow both, you are reading two feeds on completely different clocks.

The two checkboxes at the top

Above the name field sit two checkboxes, and they are easy to scroll past.

• “Check this box if no longer subject to Section 16.” The exit box. The person has left the role that made them a reporting insider. Instruction 1(b) is explicit that checking it does not end the obligation — “Form 4 and 5 obligations may continue to be applicable” — because trades made shortly after someone stops being an insider can still be reportable.
• The Rule 10b5-1(c) box. Checked when the transaction was made under “a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c)”. In plain terms: this sale was scheduled in advance by a plan, not decided this week. General Instruction 10 also requires the filer to give the plan’s date of adoption in the “Explanation of Responses” section at the bottom of the form.

That second box is new enough that a lot of older commentary predates it. The SEC’s own fact sheet for the 2022 rulemaking states that “Section 16 reporting persons will be required to comply with the amendments to Forms 4 and 5 for beneficial ownership reports filed on or after April 1, 2023”. Before that date, whether a sale came from a pre-scheduled plan was usually only discoverable from a footnote, if the filer chose to add one. Now it is a field, and an unchecked box on a large sale is a different fact from a checked one.

Table I and Table II

The body of the form is two tables, and the split is between real shares and claims on shares.

• Table I — Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned. Ordinary stock. Its columns run: title of security, transaction date, deemed execution date, transaction code, amount acquired (A) or disposed of (D), price, amount beneficially owned following the reported transactions, ownership form — direct (D) or indirect (I) — and the nature of any indirect ownership.
• Table II — Derivative Securities Acquired, Disposed of, or Beneficially Owned. The form gives its own examples: “puts, calls, warrants, options, convertible securities”. It carries everything Table I does plus a conversion or exercise price, a date exercisable, an expiration date, and the title and amount of the underlying security.

Two columns in Table I decide how much a headline number is worth. The first is Price: General Instruction 5 requires prices “in U.S. dollars on a per share basis, not an aggregate basis”, so the dollar figure you see quoted anywhere is somebody’s multiplication, not a field on the form. The second is Ownership Form: Direct (D) or Indirect (I). An indirect holding means the shares sit in a trust, a partnership, a spouse’s name or a similar arrangement, and Instruction 4(b)(iii) requires the filer to state the nature of it as specifically as possible — “By Self as Trustee for X,” “By Spouse,” “By X Trust”.

The transaction code is the filing

Column 3 of Table I and column 4 of Table II hold a one-letter transaction code, and it is the field that determines what the filing means. General Instruction 8 lists every valid code in five named groups. The groups are not decoration: they tell you whether the insider acted in the market or whether the company acted on the insider.

Two of these behave as modifiers rather than events. Instruction 8 says that when a transaction is voluntarily reported earlier than required, the filer places V in a separate column beside the code, and that a transaction involving an equity swap uses Kin addition to whatever else describes it — the instruction’s own examples are S/K and P/K. So a code cell containing a slash is normal, not a data error.

The five codes that carry most of the meaning

• P — open market purchase. The insider bought shares with their own money at a market price. This is the code that gives “insider buying” whatever meaning the phrase has, and it is much rarer than the volume of insider-buying headlines implies.
• S — open market sale. A real sale, but a weak signal on its own. Check the 10b5-1 box before reading anything into it: a sale scheduled months earlier by a plan and a sale decided on Tuesday look identical in the share count.
• A — grant or award. Shares the company gave the insider as compensation. It increases their holding without them having decided anything, and it is the most commonly misread code on the form, because a naive feed shows it as an acquisition.
• F — shares withheld for tax. When an award vests, a slice is withheld to pay the resulting tax bill. It is a disposition, it is often large, and it is close to uninformative. An F appearing a day or two after an A or M is the ordinary rhythm of executive compensation, not a change of view.
• M — option exercise. The insider converted options into shares. Frequently followed immediately by an S on the same or next filing, which together are one transaction — exercise and sell — rather than a purchase and a sale.

The practical consequence: an alert saying “an officer acquired 400,000 shares” is not a claim about anything until you know whether the code was P or A. Most of the time it is A.

What a Form 4 does not tell you

• Why.There is no field for motive, and no requirement to add one. The only free text is the footnotes and the “Explanation of Responses” box.
• Whether it was a good idea. Insiders are as capable as anyone of being wrong about their own company. Filing a purchase is not a forecast.
• The full picture of what they own elsewhere. A Form 4 reports beneficial ownership of the issuer’s securities. It says nothing about the rest of their portfolio, so a sale that looks enormous against their position may be small against their net worth, and vice versa.
• A deal price.Prices are per share and exclude “brokerage commissions and other costs of execution”, per Instruction 5. Where a transaction happened across a range, filers typically report a weighted average and explain the range in a footnote.

Where to read Form 4s for free

EDGAR, the SEC’s own system, at sec.gov/edgar/search. Filter by form type 4 and either a company or a person, and you get the filings themselves — no account, no fee, no intermediary. Each filing renders as a readable document and is also available as XML, which is what every insider-tracking product in existence is parsing.

The reason products exist on top of a free public database is volume, not access. Thousands of Form 4s are filed in a busy week, most of them code A and code F noise, and reading them by hand means opening one document at a time with no way to sort by anything you care about.

Where StockPlus fits, and where it does not

StockPlus is our app, so treat this section as the disclosure it is. Its insider feed is free on both plans with no ticker limit, and shows each filing as the insider’s name, whether it was a buy or a sale, the dollar value — or the share count where the filing carries no price — and how long ago the transaction happened.

Now the part this article makes it impossible to skip. Written out plainly, as of August 14, 2026:

• The transaction code is not shown. Only code P counts as a buy and only code S as a sale. Every other code — A, F, M, G and the rest — is bucketed as “other” and left out of the buy and sell totals. That is a defensible default, and it is not the same as showing you the letter.
• The 10b5-1 checkbox is not carried at all. There is no way to tell a scheduled plan sale from a discretionary one inside the app. For that you need the filing.
• The date shown is the transaction date, not the filing date. Both exist in the data; only the transaction date is displayed, so the feed shows no disclosure lag.
• The feed is not a sweep of every Form 4 filed. It is built from a data provider rather than read from EDGAR directly, and it covers the tickers StockPlus syncs — a seed set plus every ticker any user has on a watchlist — over a rolling recent window.

So: good for noticing that someone bought, not built for the forensic read. If the distinction between P and A is what you are there for — and after reading this you should probably want it — open the filing on EDGAR, or use a tool built specifically around Section 16 data. We would rather say that than let a summary imply it carries information it does not.

Where to read next

• Insider trading tracker — what the feed shows, what it costs, and what it leaves out.
• The STOCK Act’s 45-day rule — the congressional equivalent of this deadline, and why it is so much slower.
• When companies report earnings — the other filing calendar the market runs on, with the deadlines quoted the same way.