Question 1

What is the difference between ISOs and NSOs?

Accepted Answer

Incentive stock options (ISOs) and non-qualified stock options (NSOs) differ primarily in tax treatment. NSOs are taxed as ordinary income on the spread (market price minus strike price) at exercise, with the employer withholding federal, state, and FICA taxes. ISOs have no regular income tax at exercise, but the spread can trigger the alternative minimum tax (AMT). If you hold ISO shares for more than 1 year after exercise and 2 years after the grant date (a qualifying disposition), the entire gain is taxed at the lower long-term capital gains rate.

Question 2

What is the alternative minimum tax (AMT) and how does it affect ISOs?

Accepted Answer

The alternative minimum tax (AMT) is a parallel tax system that adds back certain deductions and income items. For ISO holders, the spread at exercise (market price minus strike price) is added to your AMT income even though it's not taxed under the regular system. If your AMT calculation produces a higher tax than your regular tax, you pay the difference as AMT. This can create a significant unexpected tax bill when exercising ISOs with a large spread.

Question 3

When should I exercise my stock options?

Accepted Answer

The optimal exercise timing depends on several factors: your option type (ISO vs NSO), the current stock price relative to your strike price, your overall tax situation, expiration date, and cash available for exercise costs. For NSOs, exercising and selling immediately locks in the spread but triggers ordinary income tax. For ISOs, early exercise when the spread is small minimizes AMT exposure, while waiting for appreciation maximizes potential gains but increases AMT risk. Consider exercising in low-income years to reduce the tax impact.

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ISO vs NSO Comparison

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