Tax policy influences the size of the U.S. economy and the income of Americans by altering incentives for work and investment. The Tax Foundation’s general‑equilibrium model captures how changes in after‑tax returns affect these decisions and, consequently, long‑run economic outcomes.
How incentives shape work and investment
- Individuals compare the after‑tax return of an additional hour of work or an extra dollar of investment with the next best alternative.
- When a tax reduces the marginal return, workers and investors cut back on labor supply or capital deployment.
- Projects that previously broke even may become unprofitable, leading to lower overall investment and fewer full‑time‑equivalent jobs.
Impact on macroeconomic aggregates
- GDP (gross domestic product) reflects total U.S. output.
- GNP (gross national product) measures the income earned by U.S. residents, regardless of where the production occurs.
Tax changes that affect the return to domestic saving—most notably capital‑gains taxes—can create a divergence between GDP and GNP:
- Higher capital‑gains taxes lower the after‑tax return on saving.
- Domestic savers respond by reducing their savings, which diminishes the domestic ownership of U.S. investment assets.
- Because the U.S. economy is open to foreign capital, foreign investors (who are not subject to the U.S. tax) may fill the financing gap, sustaining the level of GDP.
Consequences of foreign investment
- While foreign capital can mitigate the drop in GDP caused by higher taxes, it shifts asset ownership away from U.S. residents.
- The shift reduces national income (GNP) as a larger share of profits accrues to foreign owners.
- The net effect is a smaller share of U.S. wealth and income remaining with American households, even if total output stays relatively stable.
Key takeaways from the model
- Tax policy that lowers marginal after‑tax returns to work or investment contracts the long‑run size of the economy.
- Taxes on domestic saving generate a wedge between output (GDP) and resident income (GNP) by encouraging foreign financing.
- The model highlights the importance of considering both the size of the economy and the distribution of asset ownership when evaluating tax reforms.
Source article: taxfoundation.org
