Stock Options and the AMT Trap: A Pre-Exercise Checklist for Tech Employees

Exercising incentive stock options (ISOs) can produce a five-figure tax bill in a year you sold nothing and received no cash. The spread between strike price and fair market value at exercise is invisible to regular income tax and fully countable under the alternative minimum tax (AMT), and it lands on next April's return.

ISOs and NSOs Are Taxed on Different Clocks

With a nonqualified stock option (NSO), the spread at exercise is ordinary income immediately: it hits your W-2 and your employer withholds. With ISOs, the spread skips regular income tax at exercise and counts as an AMT preference item, added back under the parallel tax system.

For 2026, the AMT exemption is $90,100 for single filers and $140,200 for married couples filing jointly. It phases out by 50 cents for each dollar of AMT income above $500,000 (single) or $1,000,000 (joint). Above the exemption, a 26% or 28% rate applies, and one large exercise can clear those thresholds in a single year.

The Number That Decides How Many Shares You Exercise

AMT income from ISOs equals fair market value at exercise minus strike price, times shares exercised, added to your other AMT income and reduced by the exemption.

An illustrative example. A senior engineer with $180,000 in W-2 income files jointly and exercises 10,000 ISOs with a $5 strike on stock valued at $30. The preference item is ($30 - $5) x 10,000 = $250,000. Assuming no other adjustments, combined AMT income is $430,000. After the $140,200 exemption, $289,800 is subject to AMT, a tentative minimum tax of roughly $76,000. Her 2026 regular tax on $180,000 of wages (after the $32,200 standard deduction) is about $21,900, so the exercise adds roughly $54,000 of AMT on top.

Your safe-exercise threshold is the number to find: the shares you can exercise this year before AMT liability passes regular tax liability. It moves with your other income, filing status, credits, and any AMT carryforward credits from prior years. This belongs in your tax plan before you exercise.

The Early-Exercise and 83(b) Play

At a company that has not yet had its initial public offering (IPO), there is a narrower opening: exercise immediately after grant, while fair market value still equals your strike, and file an 83(b) election within 30 days.

With a zero spread there is no AMT preference item, and your capital gains holding clock starts early. If the company succeeds, the gain from that low basis is long-term capital gain, with none of it taxed as ordinary or AMT income. The cost is real cash into shares that could end up worthless. The 30-day window is absolute.

The Takeaway

Your answer turns on how much room sits between your regular tax liability and your AMT liability, and that room depends on income you have not earned yet this year.

The people who get hurt usually did the math. They model an exercise correctly in September, then a bonus or a second vest lands in December and moves the threshold underneath them. The bill shows up in April, after the year that could have fixed it has closed.

If you hold ISOs with a meaningful spread and an uncertain rest-of-year, that combination is worth a conversation while there is still time to act.

The information provided is for educational purposes only and does not constitute investment, legal, or tax advice. Consult with qualified professionals for guidance specific to your situation.