Source Digest — CBPP, Where Do Federal Tax Revenues Come From?

Status (April 2026): Complete standard digest. Reference overview of U.S. federal revenue composition from a progressive research organization. Counterpart to the Tax Foundation historical-rates digest; offers a different compositional lens (payroll vs. income vs. corporate vs. excise) that reframes what "the income tax" has become over the 20th century.

Source identification

Thematic cluster: composition of federal revenues

Core claims

• Three taxes account for over 90% of federal revenue in FY 2024:
  • Individual income taxes: ~49% of total federal revenue.
  • Payroll taxes (Social Security, Medicare, Unemployment Insurance): ~36% of total revenue.
  • Corporate income taxes: ~10%.
  • Excise, estate, customs, and miscellaneous: ~5% combined.
• Individual income taxes have grown modestly as a share of federal revenue since the 1950s; payroll taxes have grown dramatically.
• Corporate taxes have declined from ~30% of federal revenue in the 1950s to ~10% today.
• Total federal revenue has hovered between roughly 15% and 20% of GDP across the post-WWII period, with limited long-run trend.

Representative statistic

"Over the past 60 years, federal revenue has fluctuated between about 15 percent and 20 percent of the U.S. economy. While this share has varied, it has not shown an upward trend — despite the growth in programs funded by federal revenues."

Research context

Interpretive notes

• Composition reframes the ratchet claim. The Friedberg-Higgs ratchet argument emphasizes the growth of the state's claim on private activity. If measured by total federal revenue as a share of GDP, that claim has been notably stable over 60+ years. If measured by the stock of binding rules (per the Mercatus digest), it has grown. Both measures are legitimate. The exchange should be explicit about which it is using.
• Tax-base composition is itself a policy choice. The shift from corporate to payroll tax reliance is not an inevitable consequence of growth. It is the product of specific statutory and administrative choices. A rebalancing would not require a new tax regime — only renegotiation of the existing mix.
• Progressive lens: CBPP emphasizes that the existing tax code is less progressive than commonly assumed, because payroll taxes are regressive at the top (capped) and consumption taxes (excise, tariffs) fall more heavily on low-income households. This is relevant to Round 2 property-rights questions: the marginal statutory top rate is not the same as the realized effective rate, and redistribution happens (or fails to happen) through composition as much as through rates.

Project 2028 mapping

• Exchange: Government Overreach, Ownership as Transition, and the Ratchet Problem. Provides the countervailing empirical frame to the Tax Foundation historical-rates digest: revenue share of GDP is stable, even as statutory top rates and program spending have changed.
• Problem Map: Domain 10 (Wealth and power concentration) and Domain 15 (Democratic process) — the question of what a "fair" federal revenue composition looks like is a Layer 4 question, and the empirical record CBPP catalogues is a precondition to answering it.
• Principles: Tests Principle 2 (essential needs) and Principle 5 (public-interest governance). The project's commitment to provisioning essential needs has fiscal implications; CBPP's data clarifies the current baseline.
• Round 2 use: Useful for making the Round 1 point that total federal revenue-to-GDP has been stable: the composition and targeting of spending, not the total, is what has changed most over the last 60 years.

Cross-references