Exercise Window
The time period during which you can exercise your vested stock options.
Definition
The exercise window is the period during which you are allowed to exercise your stock options. While employed, you can generally exercise anytime after vesting. The critical window is after you leave: the post-termination exercise period (PTEP) determines how long you have to exercise after departure. The standard PTEP is 90 days, but some companies offer extended windows of 1-10 years.
Why it matters
A 90-day post-termination exercise window can force you to make a major financial decision under time pressure. If exercising costs $50,000+ and the company is still private, you are spending real money on illiquid stock. Negotiate for an extended window if possible.
Example
You leave a company with 30,000 vested options at a $5 strike. The standard 90-day window means you must spend $150,000 within 3 months or lose everything. A company with a 10-year window lets you wait for a liquidity event.