Alternative Minimum Tax Credit (AMTC): Deferral Items and Form 8801

The alternative minimum tax credit lets you recover alternative minimum tax (AMT) you paid in an earlier year because of timing differences between the regular tax and the AMT. You claim it on IRS Form 8801, it reduces your regular tax dollar for dollar in years when you’re no longer in AMT, and any unused amount carries forward indefinitely until it’s fully absorbed.¹

Why a Prior-Year AMT Payment Becomes a Credit

The AMT is a parallel calculation. You figure your tax under the regular system and under the AMT, and you pay whichever is higher. The AMT starts with your regular taxable income, adds back certain deductions and preference items, subtracts an exemption, and applies its own rates.²

Much of what you pay under the AMT is not a permanent extra tax. It’s tax the regular system would have collected later, pulled forward because the two systems recognize the same item on different schedules. The credit exists to give that prepayment back once the timing difference reverses.¹

Only Deferral Items Generate a Credit

Not every dollar of AMT you paid produces a credit. What matters is whether the item that pushed you into AMT was a deferral or an exclusion.

Deferral items are pure timing differences. Both systems eventually recognize the same amount, just in different years. Common examples include depreciation adjustments where the AMT requires slower write-offs, the spread on incentive stock options at exercise, and intangible drilling costs for oil and gas properties.¹

Exclusion items are permanent differences. They’re benefits the regular system allows but the AMT never will. The Form 8801 instructions list them: certain itemized deductions, tax-exempt interest from private activity bonds, depletion, the Section 1202 exclusion, and the standard deduction.¹ AMT triggered by any of these is a permanent cost. No credit attaches to it, because the regular system will never catch up.

That distinction is why Form 8801 doesn’t just carry your prior AMT forward. It makes you recompute what your prior AMT would have been using only exclusion items, and the difference between that hypothetical figure and your actual AMT is the credit-eligible portion, called the adjusted net minimum tax.³

Incentive Stock Options Are the Most Common Source

For individual filers, incentive stock options (ISOs) generate the AMT credit more often than anything else. Under the regular tax, exercising an ISO and holding the stock produces no taxable event. Under the AMT, the spread between your exercise price and the stock’s fair market value at exercise gets added to your AMT income right away.⁴

If that spread is large enough to trigger AMT, you’re paying tax on a gain you haven’t realized in cash. When you later sell the stock, the regular tax picks up the gain because your regular-tax basis is lower than your AMT basis. That’s when the timing difference reverses and the credit becomes usable.⁴

Exercise and sell in the same calendar year, and the two systems treat the transaction identically. No adjustment, no credit.⁴ The credit only shows up when you hold the shares past year-end.

How Much You Can Use in a Given Year

The credit is non-refundable. It can reduce your regular tax down to your tentative minimum tax for the year, and no further. It cannot produce a refund on its own. The statute caps the annual credit at the amount by which your regular tax (after most other credits) exceeds your tentative minimum tax.³

So if your regular tax is $50,000 and your tentative minimum tax is $45,000, you can use $5,000 of credit this year. If you’re still in AMT territory, meaning your tentative minimum tax equals or exceeds your regular tax, the usable credit for that year is zero. You’ll only draw down the balance in years when the regular system produces the higher tax.

2026 AMT Thresholds That Determine Whether You Can Use It

Whether you’re above or below AMT in 2026 depends on the exemption amounts and phaseouts in effect this year. For 2026:⁵

Married filing jointly or surviving spouse: $140,200
Single: $90,100
Married filing separately: $70,100
Estates and trusts: $31,400

The exemption phases out at higher incomes. For joint filers, it begins shrinking at $1,000,000 of AMT income and disappears at $1,280,400. For single filers, the phaseout runs from $500,000 to $680,200.⁵

Above the exemption, a 26% rate applies to AMT taxable income up to $244,500 ($122,250 if married filing separately), and 28% above that.⁶

Claiming the Credit on Form 8801

Individuals, estates, and trusts use Form 8801 to compute the credit and track the carryforward.¹ Pull these records before you start:

Your prior year’s Form 6251, which shows the AMT calculation and the adjustments and preferences behind it.
Your prior year’s Form 1040, for total income and regular tax figures.
Your prior year’s Form 8801, if you already had a carryforward coming in.

The form walks you through recomputing your prior year’s AMT with only exclusion items, then subtracting that hypothetical from your actual AMT to isolate the credit-eligible portion.³

The finished credit amount goes on Schedule 3 (Form 1040), line 6b, and flows to line 20 of your Form 1040, reducing your tax before the final balance or refund is calculated.⁷ Tax software moves it there automatically. On paper, attach Form 8801 to your return.

Carrying Forward What You Can’t Use

Whatever you can’t absorb this year rolls to next year, with no expiration. The statute defines the minimum tax credit as the total adjusted net minimum tax from all prior years back to 1986, less the amounts you’ve already claimed.³

You file Form 8801 again each year, enter the remaining balance, and recompute how much you can use. A large AMT bill from a single ISO exercise commonly takes five or more years to work off. Keep every year’s Form 8801 and Form 6251 until the credit is fully used, because each year’s calculation depends on the last.

A Note on the Corporate Version

Individuals file Form 8801. C corporations use a separate form, Form 8827, for their prior year minimum tax credit, and the corporate AMT itself only applies to “applicable corporations” with average annual adjusted financial statement income exceeding $1 billion over a three-year period.⁸⁹ S corporations, regulated investment companies, and real estate investment trusts are excluded from the corporate AMT entirely, so no credit is generated for them.

1
Internal Revenue Service. Instructions for Form 8801 – Credit for Prior Year Minimum Tax
2
Internal Revenue Service. Topic No. 556, Alternative Minimum Tax
3
Office of the Law Revision Counsel. 26 USC 53 – Credit for Prior Year Minimum Tax Liability
4
Internal Revenue Service. Instructions for Form 6251 (2025)
5
Internal Revenue Service. Rev. Proc. 2025-32
6
Office of the Law Revision Counsel. 26 USC 55 – Alternative Minimum Tax Imposed
7
Internal Revenue Service. Schedule 3 (Form 1040) – Additional Credits and Payments
8
Office of the Law Revision Counsel. 26 USC 59 – Other Definitions and Special Rules
9
Internal Revenue Service. Credit for Prior Year Minimum Tax – Corporations