Form 4 transaction codes explained (P, S, A, M, F, G…)
Every transaction reported on a SEC Form 4 carries a single-letter code describing how the insider acquired or disposed of the shares. Most codes describe administrative events — compensation, taxes, transfers. Only a couple describe an insider making a real market decision with real money, which is why filtering by code is the first step in any insider-trading analysis.
The codes that matter
| Code | Meaning | Signal value |
|---|---|---|
| P | Open-market or private purchase | The strongest code — insider chose to spend cash on the stock |
| S | Open-market or private sale | Weak negative — insiders sell for taxes, diversification, houses |
| A | Grant or award from the company | None — it's compensation, not a decision |
| M | Option or derivative exercise | None by itself — often paired with a same-day S |
| F | Shares withheld to pay tax on vesting | None — automatic, not discretionary |
| G | Bona fide gift | None — estate planning, charity |
| C | Conversion of a derivative security | None — mechanical |
| D | Disposition back to the company | None — usually plan-related |
| X | Exercise of in-the-money options at expiry | None — forced by the calendar |
| J | Other (described in a footnote) | Read the footnote — occasionally interesting |
Why we only track code P
A code-P purchase is the only routine Form 4 event where an insider voluntarily converts personal cash into more exposure to their own company. Codes A, M, and F dominate filing volume but carry no intent at all — counting them as "insider buying" is the most common mistake in DIY Form 4 analysis. Even S sales are weakly informative at best; see why buying and selling aren't symmetric signals.
When two or more insiders file code-P purchases in the same stock within days, that's a cluster buy — the pattern this site tracks in real time across every stock with detected activity.
Frequently asked questions
- What does transaction code P mean on a Form 4?
- Code P marks an open-market or private purchase — the insider voluntarily spent personal cash to buy company stock, making it the strongest signal among Form 4 codes.
- What does transaction code A mean on a Form 4?
- Code A marks a grant or award of shares from the company. It is compensation, not a buying decision, so it carries no signal about the insider's outlook.
- Which Form 4 codes indicate real insider buying?
- Only code P reflects a voluntary purchase with the insider's own money; codes A, M, F, G, C, D, and X describe compensation or administrative events.