Form 4 Transaction Codes Explained (P, S, F, M, A and More)
Every trade on a Form 4 carries a one-letter transaction code that says what kind of transaction it was. Only code P is a purchase on the market or from another person, and only code S is a sale of that kind. Most other codes — grants, option exercises, tax withholdings, gifts — are not buy or sell decisions in the usual sense.
Key takeaways
- P = open-market or private purchase. This is the code insider-buying screens look for.
- S = open-market or private sale.
- F = shares handed back or withheld to pay taxes or an exercise price. It is not a sale on the market.
- A = grant or award from the company, and M = exercise or conversion of an option or similar security from the company.
The codes that matter most
| Code | Official meaning (SEC) | In plain English |
|---|---|---|
| P | Open market or private purchase of non-derivative or derivative security | The insider bought shares with their own money. |
| S | Open market or private sale of non-derivative or derivative security | The insider sold shares. |
| A | Grant, award or other acquisition pursuant to Rule 16b-3(d) | The company gave the insider shares or options, usually as pay. |
| M | Exercise or conversion of derivative security exempted pursuant to Rule 16b-3 | The insider turned company-granted options or units into shares. |
| 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 | Shares were withheld to pay taxes or the exercise price, often automatically when stock vests. |
| D | Disposition to the issuer of issuer equity securities pursuant to Rule 16b-3(e) | Shares went back to the company. |
| G | Bona fide gift | The insider gave or received shares as a gift, for example to a charity or family member. |
Swipe the table to see all columns.
A typical example
An executive’s restricted stock vests. The Form 4 may show the shares arriving with code M or A, and on the same day a smaller number leaving with code F because the company withheld shares to cover taxes. Nothing was bought or sold on the market, even though shares moved in both directions. Reading only the share counts, without the codes, would give the wrong picture.
The complete list
The SEC groups the codes like this in General Instruction 8 to Form 4:
| Group | Code | Meaning |
|---|---|---|
| General | P | Open market or private purchase |
| General | S | Open market or private sale |
| General | V | Transaction voluntarily reported earlier than required |
| Rule 16b-3 | A | Grant, award or other acquisition |
| Rule 16b-3 | D | Disposition to the issuer |
| Rule 16b-3 | F | Payment of exercise price or tax liability with securities |
| Rule 16b-3 | I | Discretionary transaction, such as in a company benefit plan |
| Rule 16b-3 | M | Exercise or conversion of an exempt derivative security |
| Derivatives | C | Conversion of derivative security |
| Derivatives | E | Expiration of short derivative position |
| Derivatives | H | Expiration or cancellation of long derivative position with value received |
| Derivatives | O | Exercise of out-of-the-money derivative security |
| Derivatives | X | Exercise of in-the-money or at-the-money derivative security |
| Other exempt | G | Bona fide gift |
| Other exempt | L | Small acquisition under Rule 16a-6 |
| Other exempt | W | Acquisition or disposition by will or inheritance |
| Other exempt | Z | Deposit into or withdrawal from voting trust |
| Other | J | Other acquisition or disposition, described in a footnote |
| Other | K | Transaction in an equity swap or similar instrument |
| Other | U | Disposition by tendering shares in a change of control |
Swipe the table to see all columns.
Two codes are used together with others: K is added when an equity swap is involved (for example “S/K”), and V marks a trade reported earlier than required.
Common mistakes when reading codes
- Counting F as a sale. Tax withholdings happen automatically when stock vests and say nothing about the insider’s view.
- Counting A or M as a purchase. Grants and option exercises are part of pay, not a decision to put new money into the stock.
- Ignoring J. Code J can hide very different transactions; always read its footnote.
- Treating every S the same. Many sales are made under pre-scheduled 10b5-1 plans.
That is why InsiderHound’s buying reports count only code P, as explained in our methodology.
Sources: SEC Form 4 General Instructions, Instruction 8 (Transaction Codes); SEC Investor Bulletin: Insider Transactions and Forms 3, 4, and 5 (accessed November 9, 2026). Educational content, not investment advice.