What Is the Alternative Minimum Tax (AMT) and Who Pays It?

Bottom line: The Alternative Minimum Tax (AMT) is a separate tax calculation that runs parallel to the regular tax system. You pay whichever is higher. After the 2017 Tax Cuts and Jobs Act dramatically raised AMT exemptions, most middle-income earners no longer trigger it. High earners ($200,000+), those with large ISO stock option exercises, or filers with significant preference items should still check.

Congress created the AMT in 1969 after a report showed 155 high-income taxpayers had paid zero federal income tax by stacking deductions. The AMT was designed to impose a minimum tax regardless of how many deductions were claimed. Over decades, it began catching middle-income earners who were never its intended target — until the 2017 law reset the exemption significantly higher.

How the AMT Works

The AMT is a parallel calculation:

1. Start with your regular taxable income
2. Add back certain "preference items" and adjustments (AMT add-backs)
3. Subtract the AMT exemption
4. Apply the AMT rate (26% or 28%) to the result
5. If AMT is higher than your regular tax, pay AMT instead

The gap between what you would pay under regular tax and what you pay under AMT is the AMT liability.

AMT Exemptions for 2026 (Approximate)

The exemption phases out above these income levels, reducing the exemption by 25 cents for each dollar of AMTI above the phase-out threshold. At high enough income, the exemption disappears entirely.

Common AMT Preference Items and Add-Backs

These items reduce your regular tax but are added back for AMT purposes:

Incentive Stock Options (ISOs): The spread between the exercise price and fair market value at exercise is not taxable under regular rules — but is an AMT preference item. This is the most common AMT trigger for employees at tech companies. Exercising a large ISO grant in a single year can create significant AMT liability.

State and Local Tax (SALT) deduction: The $10,000 SALT deduction allowed under regular rules is added back entirely for AMT. If you paid $30,000 in state and property taxes and deducted $10,000 on Schedule A, that $10,000 is added back in the AMT calculation.

Accelerated depreciation: Certain business depreciation claimed faster under regular tax is added back for AMT.

Certain tax-exempt interest: Interest from some private activity municipal bonds is tax-free under regular rules but a preference item under AMT.

Who Is Still at Risk

Post-2017, AMT primarily affects:

• Employees with ISOs exercising large grants in a single year
• Very high earners above the phase-out thresholds where the exemption is reduced or eliminated
• Filers with specific deductions that are allowed under regular rules but disallowed for AMT (primarily large SALT deductions in states with high taxes)
• Certain business owners with specific depreciation or preference items

If your income is under $200,000 and you do not have ISO options, AMT is unlikely to affect you. Tax software calculates it automatically — if no AMT is due, it does not appear on your return.

Checking Your Exposure

The simplest check: run your tax software through completion and look at Form 6251 in your tax documents. If the AMT line is zero or the regular tax exceeds AMT, you are not paying AMT. If AMT exceeds regular tax, you have an AMT liability.

For ISO holders, model the AMT impact before exercising options — not after. The decision to exercise, when to exercise, and how many shares to exercise are all AMT planning decisions.

AMT exemption amounts, phase-out thresholds, and preference items are subject to legislative change. Verify current figures at IRS.gov.