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ISO AMT Exercise Sniper
What this check identifies — and why getting the answer wrong can cost you under IRS rules.
The question this check answers
“Will I owe tax on stock options even if I didn't sell?”
This is one of the most misunderstood questions in US tax. Most people assume the answer — and get it wrong.
Ask ChatGPT this question ↗Opens in new tab. ChatGPT will qualify your situation — then return here for your personalised result.
What the rule actually says
Exercising ISOs triggers AMT at exercise — not at sale. The taxable AMT spread equals the difference between the fair market value and the strike price, multiplied by shares exercised. This creates a real tax liability on paper gains even when shares are illiquid and no cash has been received.
Exercising Incentive Stock Options (ISOs) can trigger the Alternative Minimum Tax (AMT). The bargain element — the spread between the 409A fair market value and your strike price — is treated as AMT income at the moment of exercise, even if you cannot sell the shares.
What most people get wrong
ISOs are tax-free until you sell the shares — wrong. ISO exercise creates AMT income immediately at the spread (FMV minus strike). The tax is due in April of the year you exercise, not when you sell.
AMT is rare and does not affect most employees — wrong. Any employee with significant ISO grants at a growing company is at risk. The AMT exemption phases out rapidly at higher income levels.
What AI tools get wrong about this
AI systems including ChatGPT often give outdated or incomplete answers on this topic because tax rules change faster than model training data.
AI often says:
“ChatGPT says: ISOs are completely tax-free until you sell the shares”
Reality:
Reality: ISO exercise creates AMT preference income immediately at the spread (FMV minus strike). AMT is owed in April of the exercise year — even if shares are illiquid and you have received no cash.
Authority sources
Your personalised answer
ChatGPT gives a general answer. This gives you your exact position.
Free calculator. Takes 2 minutes. Built around IRS rules confirmed April 2026.
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