Post-termination exercise period

In accounting, post-termination exercise period means how long a departing holder has to exercise vested options before they lapse — often 90 days, because an ISOEquity & financingIncentive stock optionA stock option meeting IRC §422: employees only, granted under a stockholder-approved plan, strike at least fair market value, exercisable for no more than ten years. No regular tax at grant or exercise (the spread can trigger AMT); gain is capital if the stock is held two years from grant and one from exercise. Only $100,000 of stock, valued at grant, may first become exercisable in a calendar year exercised more than three months after employment ends is taxed as an NSOEquity & financingNonstatutory stock optionA stock option that is not an ISO — any grant to a contractor or director, and an ISO's excess over the $100,000 limit. With no readily determinable value at grant, the spread is ordinary income at exercise, as wages for an employee. A plan may allow longer; the options then lose ISO treatment, not validity.