Check your grant letter or equity portal. It will say “incentive stock option,” “non-qualified” (or “non-statutory”), or “restricted stock unit.” If it has a strike price and doesn't say incentive, it's probably an NSO.
- ISO (Incentive stock options): The right to buy shares at a fixed strike price, with tax advantages if you hold long enough.
- NSO (Non-qualified stock options): The same right to buy at a strike price, but without the special tax treatment.
- RSU (Restricted stock units): A promise of actual shares, delivered as they vest. There's nothing to buy.
Read the full primer