Alternative Minimum Tax: Who Still Owes It and Why

Alternative Minimum Tax: Who Still Owes It and Why

The alternative minimum tax is a second way of calculating your federal income tax, built to make sure people with large deductions and certain kinds of income still pay something. Most people never encounter it now. A small group, mostly people with stock options, still do, and for them it can be the largest surprise on a return.

You pay whichever calculation comes out higher, the regular one or the alternative one. If the alternative one wins, the difference is the extra tax. It is not a surcharge on top of everything. It is a parallel calculation with different rules.

Doug Johnson CPA, a Los Angeles firm whose live profile lists Equity Compensation as a specialty, is the firm written up here as one place to ask about it. This is an explainer, not a ranking. Doug Johnson CPA is a vetted Sam's List member and a paying member of our featured program; payment does not buy the language we use or its reviews.

What the Alternative Minimum Tax Is and How the Second Calculation Works

The alternative minimum tax starts with your regular taxable income and then adds back certain deductions and items that the regular system treats favorably. The result is alternative minimum taxable income. From that, the law subtracts an exemption amount, which is larger for married couples than for single filers, and applies two rates, generally 26 percent on the first slice and 28 percent above it. The result is compared with your regular tax, and Form 6251 is where the comparison is made.

The add-backs are the heart of it. The most common ones for individuals are the bargain element from exercising incentive stock options, which we cover below, and the deduction for state and local taxes, which the alternative calculation does not allow. Others include interest on certain private activity bonds and some depreciation differences for business owners.

The limitation: this is a general description. Which items apply to you depends on your income, your deductions and your investments, and the amounts change, so rely on a current-year calculation, not a rule of thumb.

Why Fewer People Owe the Alternative Minimum Tax Now

For years the alternative minimum tax caught millions of households. The 2017 tax law raised the exemption amounts and the income levels at which the exemption starts to phase out, and the number of people who owed it fell sharply. The 2025 tax law made the higher exemption amounts permanent but lowered the income level where the phaseout starts and sped up the phaseout, beginning in 2026, which will pull some high earners back in.

Exemption and phaseout figures are adjusted for inflation and differ by filing status, so check the IRS figures for the year in question rather than relying on an article, including this one. The Form 6251 instructions list them.

A rough picture of who is most exposed: people with high income and large add-backs, and people who exercise incentive stock options. People with ordinary wages and the standard deduction almost never owe it.

The limitation: "fewer people" is not "no one", and the rules have moved twice in a decade. A person who has never owed it can owe it in a year with an unusual item.

Incentive Stock Options and the Alternative Minimum Tax

Incentive stock options are the classic trigger. When you exercise an incentive stock option and hold the shares, the regular tax system generally does not tax the exercise. The alternative minimum tax does. It treats the difference between the stock's fair market value at exercise and the price you paid, the bargain element, as income in that year.

Here is the illustrative shape, with invented numbers. Suppose an employee exercises options to buy 10,000 shares at $2 each when the shares are worth $12. The bargain element is $10 per share, or $100,000. The employee holds the shares. That $100,000 can be added to alternative minimum taxable income for the year, and may produce alternative minimum tax even though no stock was sold and no cash was received.

That is the trap. The tax is due in cash, based on a gain that exists only on paper, and if the stock falls before it can be sold, the tax stays paid and the gain does not materialize. This is also why a sale in the same calendar year as the exercise often changes the picture, because the add-back generally does not apply when the shares are sold in the year of exercise, though a different set of rules then applies.

The limitation: the figures above are illustrative, not a calculation. Whether tax is due, and how much, depends on your other income, the exemption in the year and whether you sell. Model it before you exercise, not after.

Form 6251 and the AMT Credit

Form 6251 is where you compare the two calculations. Software fills it in automatically from your return, which is why a person can owe the alternative minimum tax without ever having heard the phrase. If you see a line for "alternative minimum tax" on your return, this is where it came from.

There is a partial relief. When the alternative minimum tax arises from certain timing differences, such as an incentive stock option exercise, the tax you paid can generally be recovered later as a credit against regular tax, claimed on Form 8801. The credit carries forward and can be used in years when your regular tax is higher than the alternative calculation. For many people, that takes years, and the credit carries forward until used. If the stock collapses, it may take many years to recover, and the loss on the shares is subject to capital loss limits.

Ask your CPA to track the credit explicitly. It is easy to lose if nobody remembers it exists.

The limitation: not every alternative minimum tax generates a credit. Only the portion from timing differences does. Add-backs that are permanent, such as the state and local tax deduction, generally do not.

When to Model the Alternative Minimum Tax Before You Act

The best time to learn about the tax is before the exercise date. A CPA can run the regular and alternative calculations side by side with different exercise sizes, to find a number that stays below the point where the alternative minimum tax starts. Some people spread exercises across years for this reason. Others exercise early, when the spread is small.

The trade-offs are real. Waiting may mean a larger spread later. Exercising early means paying for shares that may never be worth anything, and it ties up cash. Neither is right for everyone, and that is the point of modeling it.

Doug Johnson CPA is based in Los Angeles, founded in 2024, with three employees, serving clients nationwide. Its live profile positions the firm for growing businesses in the $250,000 to $10 million revenue range and for high earners with equity compensation, and lists SMB Owners, Equity Compensation, High Net Worth Individuals and Growing Companies as specialties.

Doug Johnson CPA has 15 verified client reviews on Sam's List. Each review is submitted by an individual who identifies as a client of the firm and rates it on communication, subject-matter knowledge, and overall satisfaction. Reviews reflect those individual experiences and do not represent an endorsement by Sam's List. Doug Johnson CPA is a paying member of our featured program, and payment does not buy its reviews. Ratings and rankings are not indicative of future performance or results.

The limitation, plainly: the profile lists minimums of $250,000 in income and $250,000 in revenue, so a person with a smaller income may fall outside them. It does not say how the firm prices a one-time modeling project, so ask whether it will do one before an exercise date.

Frequently Asked Questions

What is the alternative minimum tax?

It is a parallel federal income tax calculation that adds back certain deductions and items, subtracts an exemption, and applies its own rates. You pay the higher of the regular tax or the alternative minimum tax. It is figured on Form 6251.

Do most people owe the alternative minimum tax?

No. Higher exemption amounts under recent law mean few households owe it, though the 2026 phaseout change may increase the number. It still affects people with large add-backs, such as high earners and those who exercise incentive stock options. Check the current-year IRS figures with your tax professional.

Why do incentive stock options trigger the alternative minimum tax?

When you exercise and hold the shares, the bargain element is generally added to alternative minimum taxable income in the year of exercise, even though you have not sold anything. The regular tax system generally does not tax the exercise. Modeling the exercise first can avoid a surprise.

Can I get the alternative minimum tax back?

Sometimes. Tax paid because of timing differences, such as an incentive stock option exercise, generally produces a credit that can be claimed on Form 8801 in later years when your regular tax is higher. It can take years, and permanent add-backs do not produce a credit.

If you hold options, list each grant with its exercise price and expiration date before you meet a CPA. You can browse accountants on Sam's List, including the firm above, and ask each one how it models an exercise.

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About the author: Kimberly Green is the cofounder of Sam's List, where business owners and high earners find vetted CPAs, financial advisors, and fractional CFOs. She's met one-on-one with 400+ financial professionals and writes from the real data behind thousands of client-advisor matches. Ask her anything about finding an accountant - she's heard it all, including the questions people are afraid to ask.