SEC Form 4 transaction codes: what every letter means
Every line on a Form 4 carries a single-letter code saying what kind of transaction it was. The letter is the most important thing on the row, and it is the thing most often skipped.
The codes below are reproduced from the SEC's own Form 4 instructions — General Instruction 8, read 14 August 2026. This page states what each code records. What any particular filing means for a company is a separate question, and one the form itself does not answer.
The six you will actually see
Across the filings behind our insider filing pages, these six account for almost every row:
| Code | What it records |
|---|---|
| P | Open market or private purchase |
| S | Open market or private sale |
| M | Exercise or conversion of a derivative security — typically an option becoming stock |
| F | Securities delivered or withheld to pay the exercise price or the tax on a grant that vested |
| A | Grant or award of securities |
| G | Bona fide gift |
Why M and F are not sales
This is the single most common misreading, and it is worth being precise about.
M is an option exercise. Shares are created from a derivative the person already held; nothing is sold on the open market by that code alone. F is the company withholding shares to cover the exercise price or the tax bill on vesting — the recipient does not choose the amount or the timing.
Both routinely dwarf the actual purchases and sales in share count. A tool that adds up "shares disposed" without reading the code will report an insider as having sold millions of dollars of stock when what happened was a grant vesting and the payroll tax being settled. Our pages label each code as what it is, and never aggregate across codes, precisely because that arithmetic produces a number that is not true of anything.
The complete list
Straight from Instruction 8, grouped as the SEC groups them.
General transaction codes
| Code | Definition |
|---|---|
| P | Open market or private purchase of non-derivative or derivative security |
| S | Open market or private sale of non-derivative or derivative security |
| V | Transaction voluntarily reported earlier than required |
Rule 16b-3 transaction codes
| Code | Definition |
|---|---|
| A | Grant, award or other acquisition pursuant to Rule 16b-3(d) |
| D | Disposition to the issuer of issuer equity securities pursuant to Rule 16b-3(e) |
| F | Payment of exercise price or tax liability by delivering or withholding securities incident to the receipt, exercise or vesting of a security issued in accordance with Rule 16b-3 |
| I | Discretionary transaction in accordance with Rule 16b-3(f) resulting in acquisition or disposition of issuer securities |
| M | Exercise or conversion of derivative security exempted pursuant to Rule 16b-3 |
Derivative securities codes
Except for transactions exempted pursuant to Rule 16b-3.
| Code | Definition |
|---|---|
| C | Conversion of derivative security |
| E | Expiration of short derivative position |
| H | Expiration (or cancellation) of long derivative position with value received |
| O | Exercise of out-of-the-money derivative security |
| X | Exercise of in-the-money or at-the-money derivative security |
Other Section 16(b) exempt transaction and small acquisition codes
| Code | Definition |
|---|---|
| G | Bona fide gift |
| L | Small acquisition under Rule 16a-6 |
| W | Acquisition or disposition by will or the laws of descent and distribution |
| Z | Deposit into or withdrawal from voting trust |
Other transaction codes
| Code | Definition |
|---|---|
| J | Other acquisition or disposition (describe transaction) |
| K | Transaction in equity swap or instrument with similar characteristics |
| U | Disposition pursuant to a tender of shares in a change of control transaction |
Three mechanics most explanations leave out
1. V is not really a transaction code. It goes in its own column to mark that a transaction was reported earlier than the deadline required. A row can carry V alongside its actual code.
2. K combines with another code. The instructions are explicit: where an equity swap is involved, K is used in addition to the code that best describes the transaction — so you will see compound codes written `S/K` or `P/K`. A parser that treats the code field as a single letter will mis-handle these.
3. J means "read the footnote". If a transaction is not specifically listed, the filer uses J and must describe it in the explanation of responses. A J row without its footnote is incomplete by design — the meaning is in the prose, not the code.
The separate 10b5-1 checkbox
Form 4 also carries a checkbox, added under General Instruction 10, indicating whether a transaction was made under a Rule 10b5-1(c) trading plan — a contract or written instruction adopted in advance. The adoption date goes in the explanation of responses.
This matters when reading any sale: a sale executed under a plan adopted months earlier was scheduled before whatever is in today's news. The checkbox is where that is recorded, and it is a different field from the transaction code.
Where to go next
For how these filings are read — including which interpretations hold up and which are folklore — see what insider buying and selling actually signals. For the wider set of filings a company makes, see filings and events that move a stock.
To look up a specific company's recent Form 4s with each code already translated, use the insider filing tracker.
