Reading Form 4: Insider Transaction Codes Decoded

Codes Matter More Than Numbers

A "$2M insider sale" headline hides what actually happened: was the sale an open-market discretionary decision (S, not under a plan), a scheduled 10b5-1 liquidation (S-Plan), an option exercise with same-day sale (M then S), or a gift (G)? Each has a completely different information content. A CEO dumping $2M discretionary after a bad earnings call is meaningful; the same CEO selling $2M on a plan date set 12 months ago is noise. Reading the table without the codes is worse than not reading it.

What the Transactions Table Shows

The Insider Transactions table lists every Form 4 filed in the trailing 180 days with transaction date, insider name + role, code, shares, price, net dollar value, and a flag for 10b5-1 coverage. Clicking a row expands the underlying SEC filing link. The table defaults to sort by date descending, but the most useful sort is dollar value, code = P (open-market purchase) — that surfaces the trades where an insider chose to use personal cash to buy.

The Codes That Matter

Six codes cover 95% of what you'll see. P (open-market purchase) — the strongest bullish signal, especially by non-director officers using their own cash. S (open-market sale) — ambiguous alone; check for 10b5-1 coverage. M (option exercise) followed by S (sale) on the same day — mechanical; ignore. A (award) — grants, not a decision; ignore. G (gift) — often tax-motivated; weakly bearish. F (tax withholding sale) — forced; ignore. Filter aggressively: in most months, one or two P-code purchases by officers tell you more than 50 M-S exercise-sell pairs.

Where It Fits

The transactions table is the detail layer behind the MSPR chart. When MSPR spikes green, come here to verify the spike came from real P purchases, not a one-off large purchase by a single director. Combine with Institutional Holders to see whether insiders and 13F filers are moving the same direction — when they diverge, insiders have usually been right on 6-month horizons.

Open the Insider Transactions table → /app/stocks/AAPL/sentiment