Exercising incentive stock options can trigger the Alternative Minimum Tax even when you receive no cash. Enter your grant details to see the bargain element, the AMT preference it creates, and the tentative tax you may owe on Form 6251.
✏️ Your ISO Exercise
💰 AMT Bargain Element
Bargain Element ($/share)$30.00
Total AMT Preference$150,000
Exercise Cost$50,000
AMT Threshold (Single)$88,100
Estimated AMT Due$0
📊 Worked Examples
Shares
Strike
FMV
AMT Preference
Exercise Cost
5,000
$10
$40
$150,000
$50,000
10,000
$15
$22
$70,000
$150,000
2,000
$5
$50
$90,000
$10,000
1,000
$20
$20
$0
$20,000
50,000
$1
$11
$500,000
$50,000
The AMT preference equals (FMV at exercise − strike) × shares. Exercising when FMV equals the strike creates no preference; exercising deep in the money creates a large one you may owe tax on before you can sell.
📖 The ISO Exercise AMT Trap
Incentive Stock Options get favorable tax treatment — no ordinary income tax at exercise, and qualifying sales are taxed as long-term capital gains. But exercising ISOs triggers the Alternative Minimum Tax (AMT) through a "preference item" equal to the bargain element.
The bargain element
Avoidance tools aside, the AMT preference is:
Bargain element = (FMV at exercise − Exercise price) × Number of shares
You report this on Form 6251. It is added back to your AMT income even though you received no cash — you exercised and hold the shares.
AMT exemptions and thresholds (2025)
AMT exemption: $88,100 single, $137,000 married filing jointly (2025)
Phase-out: the exemption falls by 25 cents per dollar of AMTI above $626,350 (single) / $1,252,700 (MFJ)
AMT rate: 26% on the first $239,100 of AMT base (2025), 28% above
Managing the AMT hit
Exercise-and-hold-to-qualify: to get long-term capital gains you must hold 2 years from grant and 1 year from exercise — but that hold period is exactly when the AMT bill comes due.
Same-year sale (disqualifying disposition): selling in the same year eliminates the AMT preference but converts the spread to ordinary income on your W-2.
AMT credit: AMT you pay on timing items like ISO exercises generates a minimum tax credit you can carry forward and recover in later years — file Form 8801.
Exercise early in the year: gives you until the following April (or October with an extension) to see the AMT hit and sell if needed.
Frequently Asked Questions
Do I owe tax when I exercise ISOs?
Not regular income tax — there is no W-2 income at exercise. However, the bargain element is an AMT preference item, so exercising a large spread can trigger Alternative Minimum Tax even though you received no cash.
How is the ISO bargain element calculated?
It is the fair market value of the stock on the exercise date minus the exercise (strike) price, multiplied by the number of shares exercised. Exercising when FMV equals the strike produces a zero bargain element.
What is the AMT exemption for 2025?
The 2025 AMT exemption is $88,100 for single filers and $137,000 for married filing jointly. The exemption phases out at higher income levels by 25 cents for each dollar of AMT income above the threshold.
Can I get the AMT back later?
Yes. AMT paid because of timing items such as ISO exercises generates a minimum tax credit that you carry forward and use to reduce regular tax in future years. Claim it on Form 8801.
Should I sell the same year I exercise?
Selling in the same calendar year is a disqualifying disposition: it removes the AMT preference but the spread is taxed as ordinary income. Holding it preserves capital-gains treatment but exposes you to the AMT bill and to stock-price risk.
⚠️ Important: This calculator estimates the AMT preference from an ISO exercise using 2025 exemption and rate figures and a simplified AMT computation. A real Form 6251 includes many other adjustments and preferences. AMT planning is highly fact-specific — consult a tax professional before exercising a large ISO grant.