[brd529]

It's true that a company can't issue ISOs if the termination window is more than 90 days, they have to be NSOs instead. IMO the downside of the NSOs (pay tax immediately upon exercise instead of at next year's tax deadline - ISOs don't actually change the amount of tax that is due, just the timing of when you pay it) is small compared to the very real risk that your options will go poof if you don't have the cash to exercise and pay tax if there is a termination event.

[rsanek]

Startups can easily opt to convert ISOs to NSOs after the 90 days -- but of course, they typically do not.