What Is the Alternative Minimum Tax on Schedule 2, Line 1?

The Alternative Minimum Tax (AMT) is designed to ensure that certain taxpayers who benefit from specific deductions or credits still pay a minimum amount of tax. It primarily affects higher-income individuals with significant capital gains, stock options, or other tax-advantaged income. To determine AMT liability, taxpayers must complete additional calculations and report any owed amount on Schedule 2, Line 1 of Form 1040.

Who Must Fill Out This Section

Taxpayers with income sources or deductions that trigger AMT liability must complete this section. The IRS requires individuals to assess their AMT exposure if they claim tax benefits such as large itemized deductions, accelerated depreciation, or tax-exempt interest from private activity bonds. These factors can create a discrepancy between regular taxable income and AMT income, leading to additional tax liability.

A common scenario involves individuals exercising incentive stock options (ISOs). Under the regular tax system, ISOs do not generate immediate taxable income, but for AMT purposes, the bargain element—the difference between the stock’s fair market value at exercise and the option’s strike price—is considered income. This adjustment can push taxpayers above the AMT exemption threshold, requiring them to complete this section and potentially pay additional tax.

High-income earners with large state and local tax (SALT) deductions may also be subject to AMT. Since AMT disallows SALT deductions, taxpayers in high-tax states such as California, New York, and New Jersey are more likely to be affected. Similarly, those with significant passive income from real estate investments or limited partnerships may need to complete this section if their deductions reduce regular taxable income but are not permitted under AMT rules.

Calculating the AMT

The AMT is determined by recalculating taxable income under a different set of rules. This involves making adjustments, adding back tax preference items, and applying an exemption amount based on filing status.

Adjustments

Adjustments modify how certain deductions and income items are treated under AMT. One significant adjustment involves depreciation. Under the regular tax system, businesses and individuals can use accelerated depreciation methods to deduct asset costs more quickly. However, for AMT, depreciation must be recalculated using a slower straight-line method, increasing taxable income in the early years of an asset’s life.

Net operating losses (NOLs) are also limited under AMT. While NOLs can offset regular taxable income, the AMT calculation restricts the amount that can be deducted, potentially increasing tax liability. Medical expense deductions are treated differently as well—under regular tax rules, medical expenses exceeding 7.5% of adjusted gross income (AGI) are deductible, but for AMT, only expenses exceeding 10% of AGI qualify.

Preferences

Tax preference items receive favorable treatment under the regular tax system but must be added back when calculating AMT. One major preference item is tax-exempt interest from private activity bonds. While municipal bond interest is generally not taxable, interest from certain private activity bonds—issued to fund projects like stadiums or private hospitals—is included in AMT income.

Another preference item is the depletion deduction for natural resources. Taxpayers in industries such as oil, gas, and mining can claim percentage depletion, which allows them to deduct a fixed percentage of revenue rather than actual costs. For AMT, this deduction is recalculated using a cost-based method, often resulting in higher taxable income.

Intangible drilling costs (IDCs) for oil and gas exploration are also treated as a preference item. While these costs can be deducted immediately under regular tax rules, AMT requires a portion to be added back to income.

Exemptions

The AMT system includes an exemption amount that reduces taxable income, but this exemption phases out at higher income levels. For 2024, the exemption amounts are $85,700 for single filers, $133,300 for married couples filing jointly, and $66,650 for married individuals filing separately. These exemptions begin to phase out once income exceeds $609,350 for single filers and $1,218,700 for joint filers.

As income surpasses the threshold, the exemption is reduced by 25 cents for every additional dollar earned. This means that individuals with very high incomes may lose the exemption entirely, leading to a higher AMT liability.

To determine whether the exemption applies, taxpayers must calculate their Alternative Minimum Taxable Income (AMTI) by adding back adjustments and preference items. If AMTI exceeds the exemption phase-out threshold, the exemption is reduced or eliminated, increasing the likelihood of owing AMT.

Entry on Schedule 2, Line 1

Once AMT liability is determined, taxpayers must report the additional tax on Schedule 2, Line 1 of Form 1040. This figure comes from Form 6251, which calculates AMT by applying the appropriate tax rates to AMTI after accounting for the exemption amount.

After the AMT is calculated on Form 6251, the resulting amount is entered on Schedule 2. This form reports additional taxes beyond regular income tax, including self-employment tax and other special liabilities. If a taxpayer owes other amounts listed on this schedule, such as the additional Medicare tax or net investment income tax, all amounts are combined before being transferred to Form 1040, Line 17.

Electronic filing software typically automates this process, reducing the risk of errors when transferring figures between forms. However, individuals preparing returns manually must ensure consistency between Form 6251, Schedule 2, and Form 1040. Discrepancies can trigger IRS scrutiny, potentially leading to an audit or a request for clarification. Retaining supporting documentation, such as records of adjustments and preference items, is essential in case the IRS requests verification.

Immediate Tax Implications

Owing AMT can increase a taxpayer’s total tax liability and limit the ability to use certain credits that would otherwise lower tax obligations. The Foreign Tax Credit, for example, is restricted under AMT rules, which can impact individuals with foreign investment income or those working abroad.

AMT liability can also affect estimated tax payments. Individuals subject to AMT in prior years may need to adjust their quarterly estimated tax payments to avoid underpayment penalties. The IRS requires taxpayers to pay at least 90% of their current-year tax liability or 100% of the previous year’s total tax (110% for higher-income individuals) to avoid penalties under the Internal Revenue Code. Since AMT liability can fluctuate based on investment gains, stock option exercises, or changes in deductions, failing to account for this when calculating estimated payments can result in unexpected penalties at tax time.