Understanding Alternative Minimum Tax Triggers for High Earners

High earners, particularly those with incomes exceeding $150,000, often find themselves entangled in the complexities of the alternative minimum tax (AMT). The AMT is a parallel tax system designed to ensure that high-income individuals pay a minimum amount of tax, regardless of the deductions and exemptions they claim. For the 2025 tax year, the AMT exemption amounts are $81,300 for single filers and $113,700 for joint filers, with a 26% or 28% tax rate applied to the amount above the exemption.

ISO Exercises: A Common AMT Trigger

Incentive Stock Options (ISOs) are a popular form of compensation for high earners, particularly in the tech industry. However, exercising ISOs can trigger the AMT due to the spread between the grant price and the exercise price being considered taxable income. For example, if an individual exercises 1,000 ISOs with a grant price of $10 and an exercise price of $50, the $40 spread per share would be considered income, resulting in $40,000 of additional taxable income. This can push high earners into AMT territory, especially if they have other significant sources of income, such as a salary above $150,000 or substantial investment gains.

State Tax Deductions and the SALT Limit

The Tax Cuts and Jobs Act (TCJA) introduced a $10,000 limit on state and local tax (SALT) deductions, which can significantly impact high earners who itemize their deductions. For individuals residing in high-tax states like California or New York, the SALT limit can result in a substantial reduction in deductible expenses, thereby increasing their taxable income and potentially triggering the AMT. Furthermore, the inability to deduct state taxes above the $10,000 limit can also affect the deductibility of other expenses, such as mortgage interest and charitable donations, due to the overall reduction in itemized deductions.

Investment Income and the AMT

High earners often have significant investment portfolios, which can generate substantial income from dividends, interest, and capital gains. However, certain types of investment income, such as private activity bond interest and dividend income from certain foreign corporations, are considered tax preference items that can trigger the AMT. For example, an individual with $100,000 in dividend income from a foreign corporation may need to add this amount to their alternative minimum taxable income (AMTI), potentially pushing them into a higher AMT bracket. Additionally, the sale of investments can also trigger the AMT if the gains are substantial, as the long-term capital gains will be added to the individual's AMTI.

401k, IRA, and Backdoor Roth Contributions

While retirement contributions can help reduce taxable income, they may not necessarily reduce AMT liability. Contributions to a 401k or IRA are deductible from regular taxable income but not from AMTI. Therefore, high earners who contribute to these accounts may still be subject to the AMT, even if their regular taxable income is below the AMT threshold. However, a backdoor Roth IRA contribution can be a useful strategy for reducing AMT liability, as the conversion of traditional IRA funds to a Roth IRA is not subject to the AMT. For instance, an individual with $50,000 in a traditional IRA can convert this amount to a Roth IRA, potentially reducing their AMTI and lowering their AMT liability.

S-Corp and QBI Deductions

High earners who own an S-Corp or have qualified business income (QBI) may be eligible for the 20% QBI deduction. While this deduction can significantly reduce regular taxable income, it does not directly reduce AMT liability. However, the QBI deduction can indirectly reduce AMT liability by reducing the individual's regular taxable income, which in turn reduces the amount of income subject to the AMT. For example, an individual with $200,000 in QBI and a 20% deduction can reduce their regular taxable income by $40,000, potentially lowering their AMT liability if they are near the AMT threshold.

To determine if you are at risk of triggering the AMT, it is essential to understand the various triggers and how they apply to your specific situation. Our AMT calculator can help you estimate your AMT liability and identify potential triggers, such as ISO exercises, state tax deductions, and investment income. Visit our AMT calculator to get started and take the first step in minimizing your AMT liability.