Each filing reports transactions in Table I for direct equity such as common stock, or Table II for derivative securities such as options, and tags every transaction with a single-letter code — P for an open-market purchase, S for a sale, A for a compensation-plan grant, F for shares withheld to cover tax on a vesting event. The code, not the dollar value, is what separates a discretionary economic decision from a routine, plan-driven event. For a field-by-field walkthrough of the form, see the guide linked below; for all 20 codes decoded, see the GeminIQ guide to Form 4 transaction codes.