SEC Form 4 explained — insider transaction reports
A Form 4 is the filing a corporate insider submits to the U.S. Securities and Exchange Commission (SEC) to report a change in their ownership of a company’s stock. It is the single most-watched insider-trading disclosure because it captures the actual buys and sells — usually within days of the trade.
Who has to file a Form 4
Form 4 is a Section 16 filing. It applies to a company’s "insiders":
- Directors
- Officers (CEO, CFO, and other principal officers)
- Beneficial owners of more than 10% of a class of the company’s equity
The two-business-day deadline
Since the Sarbanes-Oxley Act, a Form 4 must be filed by the end of the second business day after the transaction. That tight window is why Form 4 data is close to real time — you usually learn about an insider’s trade within a day or two of it happening.
Table I vs Table II
A Form 4 has two tables. Table I covers non-derivative securities — plain common stock, the actual buys and sells. Table II covers derivatives: stock options, RSUs, warrants, and convertible notes, including when they are granted and when they are exercised into shares.
SEC Notifier builds its flow, leaderboard, cluster, and network analytics from Table I open-market activity only. Derivative lines (option grants and exercises) are mechanical and are reported with notional values that would otherwise drown out real buying and selling, so they are excluded from the dollar aggregates.
How to read a single line
| Field | What it tells you |
|---|---|
| Transaction code | What kind of event it was (P, S, A, M, F…). See the transaction-codes reference. |
| Acquired / disposed (A/D) | Whether the insider’s holding went up (A) or down (D). |
| Shares & price | Size of the trade and the per-share price (blank for grants and gifts). |
| Shares owned after | The resulting position — context for how big the trade was relative to the stake. |
| Direct / indirect (D/I) | Held directly, or through a trust, fund, or family member. |
| 10b5-1 footnote | Whether the trade executed under a pre-arranged Rule 10b5-1 plan. |
Amendments (Form 4/A)
A 4/A is a corrected re-filing. It supersedes the original — SEC Notifier marks the superseded filing so a fixed report is never double-counted.
What’s strong, what’s noise
- Strong: an open-market purchase (code P) — an insider spending their own money, especially several insiders buying together (a cluster).
- Context matters: a buy that is large relative to the insider’s existing stake or annual pay says more than a token one.
- Noisy: open-market sales (code S), which happen for taxes, diversification, or under a pre-set plan.
- Mechanical: grants (A), option exercises (M), and tax withholding (F) reflect compensation mechanics, not conviction.