The ISO Trap Just Got Sharper: How the 2026 AMT Change Can Tax Money You Never Received
You exercised your incentive stock options and held the shares. You didn't sell a single one. Not a dollar of cash changed hands.
Then, months later, a tax bill arrives — sometimes for tens of thousands of dollars — on a "gain" you can't spend, tied to stock you still own and might never sell for what it was worth the day you exercised.
Welcome to the alternative minimum tax, and the trap that has ambushed equity-rich employees for decades. As of 2026, that trap closes faster than it used to. If you're sitting on incentive stock options, this is the year to understand exactly how it works — before you exercise, not after.
Why ISOs feel like the "good" equity
Incentive stock options (ISOs) are the tax-favored cousin of the equity-comp world. When you exercise an ISO — buy your shares at your fixed strike price — nothing happens for regular income tax purposes. No W-2 income, no withholding, no line on your 1040. Hold the shares long enough — more than two years from grant and more than one year from exercise — and your eventual sale is taxed at long-term capital gains rates instead of ordinary rates.
That's the whole appeal: exercise, hold, and turn compensation into capital gains. For regular tax, exercising and holding really is a non-event.
The problem is that "regular tax" isn't the only tax system you live under.
The parallel system that sees what regular tax doesn't
First, in plain English, because a lot of high earners have never had to think about this one: the AMT — the alternative minimum tax — is a second rulebook the IRS keeps in a drawer. For most people, most years, it stays in the drawer. It exists for a single purpose: to stop high earners with lots of deductions or certain kinds of income from using those breaks to drive their tax bill too low. It does that by recalculating your taxes with many of the usual deductions and exclusions stripped out. If that stripped-down number comes out higher than your regular tax, the higher number is what you owe.
So the AMT is a second, parallel tax calculation that runs alongside your regular one. You effectively compute your tax twice — once under the normal rules, once under the AMT rules — and pay whichever comes out higher. The AMT has its own exemption, its own rates (26% and 28%), and, crucially, its own definition of income.
And under the AMT's definition, exercising an ISO is very much an event.
The moment you exercise and hold, the "bargain element" — the difference between the stock's fair market value on the exercise date and the price you paid — becomes income for AMT purposes. Not for regular tax. For AMT. So a paper gain that's completely invisible on your 1040 can quietly generate a real, cash tax bill.
Here's the nightmare version, and it isn't hypothetical — a generation of dot-com employees lived it: you exercise a large block, hold to start the capital-gains clock, and then the stock falls. You still owe AMT on the value at exercise. The value is gone. You're paying tax on money you never received and never will. The bargain element is the trap; holding is what springs it.
What changed in 2026 — the "sharper" part
For most of the last decade, the AMT faded into the background. The 2017 Tax Cuts and Jobs Act raised the AMT exemption and pushed the income levels where that exemption phases out high enough that it stopped catching most people.
The One Big Beautiful Bill Act, passed in July 2025, keeps those larger exemptions permanent — genuinely good news. For 2026 the exemption is $90,100 for single filers and $140,200 for married couples filing jointly. But the same law quietly changed the mechanics underneath, starting in 2026, in two ways that matter enormously if you exercise ISOs:
The income thresholds where the exemption starts to disappear dropped sharply — down to $500,000 for single filers and $1,000,000 for joint filers, from roughly $626,000 and $1,253,000 in 2025.
The rate at which the exemption phases out doubled, from 25 cents on the dollar to 50 cents.
Translation: once your income crosses those thresholds, your AMT exemption now evaporates twice as fast, and it starts evaporating at a lower income than before. More high earners get pulled into the AMT, and the ones who were already close get hit harder. The same ISO exercise that generated a manageable AMT bill in 2025 can generate a materially larger one in 2026.
A simplified illustration. Take a married couple with about $1 million of income — right at the new phaseout threshold. They exercise ISOs with a $100,000 bargain element. Under the 2026 rules, that extra $100,000 pushes them $100,000 into the phaseout, which strips away $50,000 of their exemption (that's the 50% rate). That $50,000 of newly exposed income gets taxed at the 28% AMT rate — roughly $14,000 of additional tax, and that's before the tax on the bargain element itself, all triggered by an exercise that put zero dollars in their pocket. Cross the threshold, and the exemption you were counting on melts as you go.
The SALT twist most people miss
Here's a second 2026 wrinkle that compounds the first. Quick plain-English translation, since this acronym gets thrown around a lot without explanation: SALT is the "state and local tax" deduction — the write-off for the state and local income and property taxes you already pay. For years, federal law let you deduct only $10,000 of it, no matter how large your actual tax bill. The same 2025 law raised that cap for regular tax — a headline relief for people in high-tax states. But the AMT has always disallowed the SALT deduction entirely.
So the SALT relief is partly a mirage: the bigger deduction helps your regular tax, then gets added right back for the AMT calculation. If you live in a high-tax state, claim a large SALT deduction, and exercise ISOs in the same year, those two forces stack — the SALT add-back and the ISO bargain element push in the same direction, straight toward an AMT bill.
Rules over feelings: how to keep the trap from catching you
The instinct with ISOs is emotional — "I believe in this company, so I'll exercise and hold everything." That instinct, left unmodeled, is exactly what walks people into an AMT bill they never saw coming. This is a math-and-timing decision, and it rewards people who treat it like one.
A few of the levers that actually matter:
Model the AMT before you exercise, not at tax time. The whole game is knowing your number in advance. There's typically an "AMT crossover" — the amount of bargain element you can absorb before you trigger AMT. Exercising up to that line, and no further, is a common way to capture ISO benefits without the surprise.
Spread exercises across multiple tax years. A block that triggers a painful AMT bill in a single year may cost little or nothing split across two or three — especially now that the phaseout is steeper.
Mind the calendar. Exercising early in the year gives you until December to watch the stock and decide whether to hold (the capital-gains path, with AMT exposure) or sell in the same year. A same-year sale is a "disqualifying disposition" — you give up long-term capital-gains treatment, but the bargain element becomes ordinary income and the AMT preference disappears. Sometimes that's the smarter trade; sometimes it isn't. The point is that you only get to choose if you've kept the option open.
Remember the Minimum Tax Credit. AMT you pay because of an ISO exercise is, in many cases, a timing difference rather than a permanent loss — it can generate a credit (Form 8801) that comes back to you in later years. That doesn't make the cash-flow hit painless, and it won't help if the stock collapses, but it does mean the AMT bill is often a prepayment, not money gone for good.
Watch the SALT interaction if you're in a high-tax state. It can be the difference between clearing the AMT and tripping into it.
The bottom line
The feature that makes ISOs so attractive — no regular tax when you exercise and hold — is the exact same feature that hides the AMT bill. The gain is invisible where you're looking and fully visible where you're not. And in 2026, with the phaseout thresholds lower and the phaseout rate doubled, the distance between "this looks free" and "this is taxable" is wider than it's been in years.
None of this means don't exercise. It means don't exercise blind. Run the numbers first, know your crossover, and decide on purpose how much of a tax bill — and how much single-stock risk — you're willing to take on in a given year.
Before you exercise, model it. Our Exec Comp Optimizer lets you run your own ISO exercise against the 2026 AMT rules and see the tax hit at different exercise sizes and timings — so the number is on your screen before it's on your tax return.
This article is for educational purposes only and is not tax or legal advice. AMT and ISO rules are technical and highly fact-specific, and your result depends on your full tax picture. Model your own situation with your CPA and tax advisor — and with our team — before exercising options or making any decision tied to equity compensation.
