"Stock options that are subject to an early exercise provision would no longer qualify for ISO treatment."
Not sure exactly what you mean by this, but I believe the same ISO rules apply if you exercise early: you don't owe taxes (under the normal income tax calculation; AMT is different for ISOs) until you actually sell the shares.
Not sure exactly what you mean by this, but I believe the same ISO rules apply if you exercise early: you don't owe taxes (under the normal income tax calculation; AMT is different for ISOs) until you actually sell the shares.