Federal Tax Policy & Income Inequality

A Tax Code That Shapes Inequality

The federal tax system is the most powerful redistributive tool available to the U.S. government — and its design choices are among the most consequential determinants of who is poor and who is not. Federal taxes raised approximately $4.4 trillion in fiscal year 2023, funding the programs that reduce poverty (Social Security, Medicaid, SNAP, EITC) while simultaneously shaping the after-tax income distribution through what the code taxes, what it exempts, and what it subsidizes.^[1]

The headline structure of the federal tax code is nominally progressive: the individual income tax applies marginal rates ranging from 10% to 37%, and high-income earners pay a larger share of income in income taxes than low-income earners. But the total federal tax burden — including payroll taxes, excise taxes, and the distributional effects of corporate taxes — is far less progressive than the income tax alone suggests. The Congressional Budget Office's distributional analysis found that in 2020, the lowest-income quintile paid an average total federal tax rate of 1.5%, while the highest quintile paid 24.4% and the top 1% paid 30.0%.^[2]

The apparent progressivity conceals critical structural features that reduce the tax code's redistributive effect: the payroll tax is regressive, capital income receives preferential rates, tax expenditures flow disproportionately to high-income households, and the EITC and CTC — the code's primary anti-poverty tools — have structural limitations that leave the poorest families with the smallest benefits.

The Payroll Tax: Regressive by Design

The federal payroll tax — which funds Social Security and Medicare — is the second-largest source of federal revenue and the largest tax paid by the majority of American workers. For approximately 65% of tax filers, payroll taxes exceed their income tax liability (2020 CBO).^[2]

The Social Security portion of the payroll tax is 12.4% of earnings (split between employer and employee) but applies only to the first $168,600 of earnings in 2024. Every dollar earned above that threshold is exempt from Social Security tax.^[3] A worker earning $50,000 pays the Social Security tax on 100% of their earnings; a worker earning $500,000 pays it on only 34% of theirs. This cap makes the payroll tax regressive at the top of the income distribution — a worker earning $168,600 pays the same Social Security tax in absolute dollars as a worker earning $10 million.

The Medicare portion (2.9% of earnings, plus an additional 0.9% surcharge above $200,000/$250,000 for couples) has no cap, partially offsetting the regressivity of the Social Security cap. But the combined effect of the payroll tax structure is that middle-income workers face higher effective payroll tax rates than high-income earners — a structural feature that compounds when layered with state and local taxes that are also regressive in most states.

Capital Gains: The Preferential Rate for Wealth

The federal tax code taxes income from capital — long-term capital gains and qualified dividends — at a maximum rate of 20%, compared to a maximum rate of 37% for ordinary income from wages and salaries. An additional 3.8% net investment income tax applies to high-income taxpayers, bringing the effective maximum rate on capital income to 23.8% — still well below the 37% top rate on earned income.^[4]

This preferential treatment of capital income has enormous distributional consequences. Capital gains and dividends are overwhelmingly concentrated among the wealthy: the top 1% of taxpayers receive approximately 70% of all long-term capital gains income and 40% of qualified dividend income (2021 IRS SOI).^[5] The preferential rate means that a hedge fund manager paying the 20% capital gains rate on carried interest income faces a lower marginal tax rate than a nurse, teacher, or plumber paying ordinary income tax rates on their wages.

The "step-up in basis at death" provision compounds this advantage: when appreciated assets are inherited, the capital gains accrued during the decedent's lifetime are never taxed. The Treasury Department has estimated that unrealized capital gains at death exceed $100 billion annually — revenue that is permanently forgone under current law, representing one of the largest untaxed wealth transfers in the federal system.^[6]

Tax Expenditures: The Upside-Down Subsidy

The federal government delivers approximately $1.8 trillion annually in "tax expenditures" — deductions, exemptions, credits, and preferential rates that reduce tax liability for specific activities (2024 JCT).^[7] This figure exceeds total discretionary federal spending. The largest tax expenditures include:

• Employer-provided health insurance exclusion (~$300 billion/year) — the largest single tax expenditure. Because the benefit is a deduction from taxable income, it is worth more to higher-income taxpayers in higher brackets. A family in the 37% bracket saves $0.37 per dollar of employer health premium; a family in the 12% bracket saves $0.12.^[7]
• Retirement account preferences (401(k), IRA, defined-benefit plans — ~$280 billion/year) — similarly structured as deductions or deferrals, delivering the largest benefits to high-income savers who contribute the most and face the highest marginal rates.^[7]
• Mortgage interest deduction (~$25 billion/year after the 2017 TCJA cap) — available only to homeowners who itemize deductions, predominantly those with incomes above $100,000. Renters — who are disproportionately low-income — receive no equivalent subsidy.^[7]
• Capital gains preferences (~$200 billion/year) — as described above, overwhelmingly benefiting the top 1%.

The Tax Policy Center has characterized this pattern as the "upside-down subsidy": tax expenditures structured as deductions from taxable income deliver the largest per-dollar benefit to the highest-income households. The CBO estimated that in 2019, the top income quintile received approximately 51% of the value of the ten largest tax expenditures, while the bottom quintile received approximately 4%.^[8] The tax code subsidizes homeownership, employer health insurance, and retirement savings at a rate inversely proportional to need.

The EITC and CTC: Progressive Tools with Structural Limits

The Earned Income Tax Credit and Child Tax Credit are the federal tax code's most effective anti-poverty provisions. The EITC distributed approximately $57 billion to 31 million workers in tax year 2022, while the CTC provided approximately $105 billion in credits (2022 IRS).^[10] Together, these credits lifted approximately 7.1 million people above the SPM poverty line in 2023 — the largest poverty-reducing effect of any federal program except Social Security.^[11]

But both credits have structural limitations that exclude or underserve the poorest Americans. The EITC is available only to workers with earned income — excluding disabled adults, caregivers, and the unemployed. The standard CTC ($2,000 per child) is only partially refundable ($1,700 in 2024), meaning families who earn too little to owe federal income tax receive less than families with higher incomes — an inversion that the 2021 expansion temporarily corrected by making the credit fully refundable.^[10]

Both credits are delivered as annual lump sums during tax filing season rather than as regular monthly income. For families living paycheck to paycheck, this delivery mechanism means that the anti-poverty benefit arrives months after the need arises. The 2021 expanded CTC's monthly delivery demonstrated both the feasibility and the poverty-reducing power of regular payment — and Congress chose not to continue it.

Federal and State Tax Interaction

Federal tax policy does not operate in isolation — it interacts with state and local tax systems in ways that compound or offset its distributional effects. The federal State and Local Tax (SALT) deduction allows taxpayers who itemize to deduct state and local taxes from their federal taxable income (capped at $10,000 since the 2017 Tax Cuts and Jobs Act). This deduction effectively subsidizes state tax revenue collection for high-income itemizers, while providing no benefit to low-income filers who take the standard deduction.^[4]

The interaction is particularly consequential in states with no income tax — where the state tax system is highly regressive (funded primarily through sales and property taxes) and the federal system provides no offsetting deduction for the taxes paid by low-income residents. A low-income family in such a state faces a regressive state tax burden and receives limited benefit from the federal code's progressive features (since they owe little or no federal income tax). The combined federal, state, and local tax burden for the bottom income quintile — averaging approximately 20–25% of income when all taxes are included (ITEP, 2024) — represents a higher effective rate than popular discourse acknowledges.^[12]

System Connections & Related Articles

Federal tax policy connects directly to every poverty condition documented on this site. The regressive payroll tax increases the effective tax rate on low-wage workers while capping the contribution of high earners. Capital gains preferences accelerate the wealth concentration that drives generational poverty and the racial wealth gap. The mortgage interest deduction subsidizes homeownership for the affluent while renters in poverty receive no equivalent benefit. The EITC and CTC represent the federal government's primary response to the benefits cliff — but their structural limitations leave the poorest families with the smallest credits. And the interaction between federal tax choices and state fiscal systems compounds the inequality documented in every article on this site, as low-income families bear the cumulative burden of tax systems designed primarily around the economic interests of those who need the least assistance.

Federal tax policy is one component of the broader US poverty paradox — the structural question of why federal choices produce the highest poverty rates among wealthy democracies. The federal safety net architecture documents the programs that tax-code delivery mechanisms like the EITC and CTC are meant to supplement — and the gaps that remain. The federal labor standards article describes the low-wage labor market that regressive payroll taxes compound. And the international poverty comparison shows how nations with more progressive tax-and-transfer systems achieve poverty rates one-third to one-half of the American level.