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Estimate vest tax

How are incentive stock options (ISOs) taxed?

ISO tax is a sequence: usually no tax at grant, possible AMT at exercise, capital gain treatment on qualifying sales.

Tax rules change. Federal and state rates, brackets, and reporting rules are updated regularly. This site is not always current. check dates below and verify with official sources or a qualified tax professional.

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The short answer

tax usually plays out in stages: generally no regular income tax at grant or at exercise, but the exercise spread can be an alternative minimum tax () item. If you meet the holding periods, a later sale can qualify for long-term treatment; if you sell too soon, part of the gain becomes .

Why this happens

receive special tax treatment compared with regular wages, which is why exercise does not usually trigger tax the way an does.

The bargain element at exercise (value minus exercise price) is generally a preference item for , so a large exercise can create even without selling.

If you hold long enough. generally more than two years from grant and more than one year from exercise. a sale can be a 'qualifying disposition' taxed as long-term .

Selling before those holding periods is a 'disqualifying disposition,' which usually converts part of the gain to .

What to check

  • Your grant type. confirm the options are actually , not .
  • The exercise price vs. current (the spread).
  • and exercise date for holding-period planning.
  • Whether an exercise could trigger for the year.
  • Forms you receive, such as Form 3921 for exercises.

Common mistake

Exercising a large position late in the year without checking . The spread can create an bill even though you sold nothing and have no cash from the shares. This is where people get surprised.

Example scenario (hypothetical)

Illustration only, not your tax situation.

Simplified and hypothetical: Sam exercises with a $10 strike when the value is $40, on 1,000 shares. There is generally no regular income tax at exercise, but the $30,000 spread may be an preference item. Whether Sam owes depends on Sam's full return. and Sam has no proceeds yet to pay it.

When to ask a CPA or tax advisor

  • You are exercising a large block.
  • You might owe and need a plan to pay it.
  • You are weighing a qualifying vs. disqualifying disposition.
  • Your shares are in a private company with an uncertain valuation.

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Educational only

This guide is for learning and planning, not tax, legal, or investment advice. Your employer, state, grant terms, and filing status can change the outcome. Confirm details with your own documents and a qualified tax professional before making decisions.