Last week, Representative Don Beyer (D-VA) and Senator Chris Van Hollen (D-MD) provided details on a proposed surtax on millionaires as part of an increased interest by policymakers to impose higher tax rates on high-income earners and the wealthy, with the goal of reducing economic inequality.

The proposed surtax would levy a 10-percentage point surtax on modified adjusted gross income (AGI) for taxpayers with an AGI above $1 million ($2 million for taxpayers filing jointly). This use of modified AGI as the surtax base contrasts with the individual income tax, which applies to taxable income after accounting for the standard deduction or itemized deductions. The surtax would apply to all income, including labor income, business income, and investment income accrued through realized capital gains and dividends.

The 10-percentage point surtax would raise the top marginal tax rate on labor income (wages and salaries) from 37 percent to 47 percent and raise the top marginal tax rate on capital income (long-term capital gains and qualified dividends) from 23.8 percent to 33.8 percent when including the 3.8 percent net investment income tax (NIIT) on taxpayers with a modified AGI above $200,000 ($250,000 filing jointly).

Economic Effects

According to the Tax Foundation General Equilibrium Model, the millionaire’s surtax proposal would reduce economic output (GDP) by 0.1 percent in the long run. Additionally, the economy would produce about 118,000 fewer jobs.

Table 1. Economic Impact of the Millionaire’s Surtax Source: Tax Foundation General Equilibrium Model, October 2019. Gross Domestic Product (GDP) -0.1% Capital Stock 0% Wages 0% Service Price of Capital 0% Full-time Equivalent Jobs -118,000

The proposed millionaire’s surtax would reduce the incentive to work by lowering the after-tax wage for high-income earners. A lower after-tax wage makes leisure relatively more attractive than labor, lowering labor supply and reducing economic output.

The surtax on capital income, such as dividends and capital gains, would reduce the after-tax returns to capital investment by Americans, lowering investment domestically. However, the reduction in investment from Americans would be offset by an increase in investment from abroad (an increase in the trade deficit), as foreigners are not subject to the surtax. Gross national product (GNP) would decline by more than GDP due to the shift in ownership of American investment assets to foreign investors.

Revenue Effects

We estimate that the millionaire’s surtax would raise $716 billion between 2020 and 2029 on a conventional basis. Tax revenue would grow over the decade as income increases, leading to a larger tax base. The millionaire’s surtax is estimated to raise $56 billion in 2020, rising to $85 billion in 2029.

Table 2. Revenue Impact of the Millionaire’s Surtax (billions of dollars) Source: Tax Foundation General Equilibrium Model, October 2019. Year 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2020-2029 Conventional Estimate $56 $62 $65 $68 $70 $73 $76 $79 $82 $85 $716

The surtax on capital gains would change when owners of unrealized capital gains realize this income. Owners of capital gains may avoid realizing their gains to avoid the surtax, lowering potential tax revenue. Using capital gains realization behavior as measured by the Joint Committee on Taxation (JCT), we estimate that the surtax would reduce capital gains realizations relative to current law by 37 percent in the first year of enactment, 31.5 percent in the second year, and by 28.2 percent thereafter.

Distributional Effects

The federal tax code would become more progressive under the millionaire’s surtax, according to the Tax Foundation General Equilibrium Model. Taxpayers in income groups below the 99th percentile would not see their after-tax incomes decline on a conventional basis.

Table 3. The Distributional Impact of the Millionaire’s Surtax Source: Tax Foundation General Equilibrium Model, October 2019 Percent-change in After-tax Income Income Group Conventional 0% to 20% 0% 20% to 40% 0% 40% to 60% 0% 60% to 80% 0% 80% to 90% 0% 90% to 95% 0% 95% to 99% 0% 99% to 100% -3.4% Total -0.5%

On a conventional basis, taxpayers with after-tax incomes in the 99th to 100th percentiles would experience a 3.4 percent decline in after-tax income when compared to current law. Overall, after-tax incomes would decline by 0.5 percent.

The millionaire’s surtax exempts taxpayers with AGI of less than $1 million filing single or $2 million filing jointly. On a conventional basis, this means that the surtax has no effect on taxpayers with after-tax incomes below the 99th percentile.