Alternative Minimum Tax (AMT) for Business Owners: How It Works, Who Pays It, and Planning Strategies
The alternative minimum tax catches business owners who benefit from provisions that reduce their regular tax below what Congress considers a fair minimum. Under IRC 55, the AMT is the excess of the tentative minimum tax over the regular tax. If your regular tax is $80,000 and your tentative minimum tax is $95,000, you owe $15,000 of AMT on top of your regular tax. After the Tax Cuts and Jobs Act raised the AMT exemption to $88,100 single and $137,000 MFJ (2025, indexed) and increased the phase-out thresholds to $626,350 single and $1,252,700 MFJ (2025), the AMT affects far fewer taxpayers than it did before 2018. But it hasn’t been eliminated, and business owners who exercise incentive stock options, live in high-tax states, or hold private activity bonds can still be caught. The AMT computation requires recalculating taxable income by adding back AMT preference items (IRC 57) and AMT adjustments (IRC 56), applying the AMT exemption (IRC 55(d)), and computing the tentative minimum tax at 26%/28% rates.
AMT computation (2025):
| Step | Single | MFJ |
|---|---|---|
| 1. Regular taxable income | X | X |
| 2. Add back AMT preferences and adjustments | + preferences | + preferences |
| 3. = Alternative minimum taxable income (AMTI) | ||
| 4. Subtract AMT exemption | ($88,100) | ($137,000) |
| 5. Phase-out: exemption reduced by 25% of AMTI over threshold | $626,350 | $1,252,700 |
| 6. Exemption fully phased out at | $978,750 | $1,800,700 |
| 7. AMT rate: 26% on first $248,300 of excess | 26% | 26% |
| 8. AMT rate: 28% on amounts over $248,300 | 28% | 28% |
| 9. Tentative minimum tax = tax from step 7-8 | ||
| 10. AMT = tentative minimum tax minus regular tax (if positive) |
Most common AMT preference items and adjustments:
| Item | Regular Tax | AMT Treatment |
|---|---|---|
| State and local tax (SALT) deduction | Deductible (up to $40K/$80K under OBBBA) | Not deductible for AMT |
| ISO exercise (bargain element) | Not taxed at exercise | Bargain element is AMT income |
| Private activity bond interest | Tax-exempt | Taxable for AMT |
| Depreciation (pre-TCJA property) | MACRS accelerated | Slower AMT depreciation (150% DB or straight-line for certain property) |
| Standard deduction | Deductible | Not allowed for AMT |
| Net operating loss deduction | Up to 80% of taxable income | Limited to 90% of AMTI (with modifications) |
| Incentive stock option (ISO) bargain element | Not taxed until sale | Included in AMTI at exercise |
When does the AMT affect business owners?
How does the alternative minimum tax affect business owners?
The AMT is a parallel tax system that adds back certain deductions and preferences to your regular taxable income to compute alternative minimum taxable income (AMTI). Common AMT triggers for business owners include the exercise of incentive stock options (ISOs), accelerated depreciation timing differences, and large state and local tax deductions. The AMT exemption amount ($85,700 for single filers, $133,300 for married filing jointly in 2024) phases out at 25 cents per dollar of AMTI above $609,350 (single) or $1,218,700 (married filing jointly). You pay whichever is higher: your regular tax or the AMT amount (26% on the first $232,600 of AMTI above the exemption, 28% on the excess). AMT paid due to timing differences (like ISO exercises or depreciation) generates a minimum tax credit that can offset regular tax in future years when those items reverse.
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Yarik Yarosh, CPA. "Alternative Minimum Tax (AMT) for Business Owners: How It Works, Who Pays It, and Planning Strategies." Blue Cloud CPA, September 5, 2026, updated September 23, 2026. https://bluecloudcpa.com/guides/small-business-alternative-minimum-tax-amt-business-owners-planning
This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.