Form 4 Filing¶
OVERVIEW¶
Form 4 is an SEC-mandated disclosure that officers, directors, and beneficial owners of more than 10% of a company's stock — collectively called Section 16 insiders — must file every time they transact in their own company's securities.
Covered transaction types include open-market buys and sells, option exercises, restricted stock vesting, gifts, and 10b5-1 plan trades.
Filing Deadline
Form 4 carries a hard two-business-day deadline from the transaction date. This makes it the fastest public window into what insiders are actually doing with their own stock, as opposed to what they say on earnings calls.
Filings are submitted electronically via SEC EDGAR and are publicly searchable within hours of submission.
FILING STRUCTURE¶
Every Form 4 is broken into structured fields across two tables.
| Table | Covers |
|---|---|
| Table I | Non-derivative securities — common stock bought or sold outright |
| Table II | Derivative securities — options, RSUs, warrants |
Each record also includes shares transacted, price, and post-transaction ownership, allowing you to compute exactly what percentage of an insider's stake changed hands.
Transaction Codes¶
The transaction code is the single most important field for reading intent.
| Code | Meaning | Signal Type |
|---|---|---|
P |
Open-market purchase | Highest-conviction — discretionary buy |
S |
Open-market sale | Weak — often routine or pre-scheduled |
A |
Grant or award | Routine compensation, not a market decision |
M |
Option exercise | Compensation mechanic |
F |
Shares withheld for tax on vesting | Automatic, not discretionary |
G |
Gift | Non-market event |
Focus on Code P
Tapeboard's insider-flow panel filters specifically for code P transactions and excludes routine A, F, and M entries, since those reflect compensation mechanics rather than active market bets.
WORKED EXAMPLE¶
Commercial Metals Company (CMC) — July 13, 2026
| Field | Detail |
|---|---|
| Filer | Peter R. Matt, President and CEO |
| Transaction code | P — open-market purchase |
| Shares purchased | 8,230 |
| Weighted average price | $61.30 |
| Total value | ~$504,600 |
Because this is a code-P purchase by the sitting CEO — not a scheduled 10b5-1 sale or an option-related transaction — it reads as a genuine conviction signal. The filing tells the market the CEO chose, out of his own after-tax cash, to add to his position at the prevailing market price.
HOW TO USE¶
Reading Insider Flow on Tapeboard¶
Tapeboard's insider-flow panel surfaces Form 4 data filtered for actionable signals. Common workflows include:
- Cluster buying screens — flag filings where multiple insiders purchase within a short window, which historically correlates with modestly better forward returns than isolated single buys
- Post-selloff setups — watch for sudden insider buying after a stock has sold off sharply, particularly when the buyer is a CEO or CFO rather than a lower-ranked officer
- Code filter — apply
P-only filters to strip out compensation noise from grants and tax-withholding events
Comparison Tools
Screeners such as OpenInsider and GuruFocus apply similar code-level filters. Tapeboard consolidates this alongside fundamentals so Form 4 signals are read in context rather than in isolation.
LIMITATIONS AND COMMON MISCONCEPTIONS¶
| Misconception | Reality |
|---|---|
| Insider selling is a strong bearish signal | Executives sell for diversification, tax planning, real estate, or divorce settlements unrelated to stock outlook |
| All sales are discretionary | A large share of sales are pre-scheduled 10b5-1 plan trades set up months in advance |
| The filed price reflects current market | The two-business-day window means the price may already be stale, especially around volatile news |
| A single Form 4 buy is a guaranteed signal | It is a probabilistic tilt, not proof of superior information — always read alongside fundamentals |
Key Principle
Insider buying is a far stronger signal than insider selling. A single purchase, however historically well-timed, should complement your analysis — not replace it.