Alternative minimum tax
The alternative minimum tax (AMT) is a tax imposed by the United States federal government in addition to the regular income tax for certain individuals, estates, and trusts. As of tax year 2018, the AMT raises about $5.2 billion, or 0.4% of all federal income tax revenue, affecting 0.1% of taxpayers, mostly in the upper income ranges.[1][2]
An alternative minimum taxable income (AMTI) is calculated by taking the ordinary income and adding disallowed items and credits such as state and local tax deductions, interest on private-activity municipal bonds, the bargain element of incentive stock options, foreign tax credits, and home equity loan interest deductions. This broadens the base of taxable items. Many deductions, such as mortgage home loan interest and charitable deductions, are still allowed under AMT. The AMT is then imposed on this AMTI at a rate of 26% or 28%, with a much higher exemption than the regular income tax.
The Tax Cuts and Jobs Act of 2017 (TCJA) reduced the fraction of taxpayers who owed the AMT from 3% in 2017 to 0.1% in 2018, including from 27% to 0.4% of those earning $200,000 to $500,000 and from 61.9% to 2% of those earning $500,000 to $1,000,000.
The major reasons for the reduction of AMT taxpayers after TCJA include the capping of the state and local tax deduction (SALT) by the TCJA at $10,000, and a large increase in the exemption amount and phaseout threshold. A married couple earning $200,000 now requires over $50,000 of AMT adjustments to begin paying the AMT. The AMT previously applied in 2017 and earlier to many taxpayers earning from $200,000 to $500,000 because state and local taxes were fully deductible under the regular tax code but not at all under AMT. Despite the cap of the SALT deduction, the vast majority of AMT taxpayers paid less under the 2018 rules.[3][4][5]
The AMT was originally designed to tax high-income taxpayers who used the regular tax system to pay little or no tax. Due to inflation and cuts in ordinary tax rates, a larger number of taxpayers began to pay the AMT. The number of households owing AMT rose from 200,000 in 1982 to 5.2 million in 2017, but was reduced back to 200,000 in 2018 by the TCJA.[6] After the expiry of the TCJA in 2025, the number of AMT taxpayers is expected to rise to 7 million in 2026.[7][8]
Growth of the AMT[edit]
Although the AMT was originally enacted to target 155 high-income households, it grew to affect 5.2 million taxpayers each year by 2017, raising $36.2 billion, or 2.4% of federal income tax revenue. The passage of the TCJA for tax year 2018, reduced the affected number to about 0.1% of all taxpayers. This number is expected to rise again in 2026 with the expiry of the individual provisions of the TCJA.
In 1997, for example, 605,000 taxpayers paid the AMT;[65] by 2008, the number of affected taxpayers jumped to 3.9 million, or about 4% of individual taxpayers, raising $26 billion of $1,031 of federal income tax revenue.[66] A total of 27% of households that paid the AMT in 2008 had adjusted gross income of $200,000 or less.[67]
The primary reason for AMT growth from 1978 to 2013 is that the AMT exemption, unlike regular income tax items, was not indexed to inflation before 2013. This means that income thresholds did not keep pace with the cost of living.[68] As a result, the tax has affected an increasing number of households each year, as workers' incomes adjusted to inflation and surpassed AMT eligibility levels. While not indexed for inflation, Congress often passed short-term increases in exemption amounts. The Tax Policy Center (a research group) estimated that if the AMT had been indexed to inflation in 1985, and if the Bush tax cuts had not gone into effect, only 300,000 taxpayers—instead of their projected 27 million—would be subject to the tax in 2010.[69] President Barack Obama included indexing the AMT to inflation in his FY2011 budget proposal, which did not pass.
The 2001–2006 Bush tax cuts also exacerbated the effects of AMT by reducing marginal tax rates (for instance, the top rate from 39.6% to 35%)[68] without making corresponding changes to AMT rates. Economists often refer to this as the "take-back effect" of the Bush tax cuts.[65]
As the AMT expanded from 1978 to 2017, the inequalities created by the structure of the tax have become more apparent. Taxpayers are not allowed to deduct state and local taxes in calculating their AMT liability; as a result, taxpayers who live in states with high income tax rates are up to 7 times more likely to pay the AMT than those who live in states with lower income tax rates.[70] Similarly, taxpayers are not allowed to deduct personal exemptions in calculating their AMT liability, resulting in large families being more likely to pay the AMT than smaller families.[71] With the passage of the TCJA which eliminated personal exemptions in favor of an expanded standard deduction, this was no longer an issue.
Standard tax texts
CBO issue brief