From the summary:
Cutting corporate tax rates will not create jobs or boost incomes for the vast majority of American families.
What proponents of corporate tax cuts argue: A central argument proponents of corporate tax cuts make is that U.S. corporations face higher tax rates than those of our peer countries; they claim that this differential hurts U.S. “competitiveness” (a word they rarely define) and discourages companies from investing in the U.S. Consequently, they further claim that cutting corporate tax rates would increase American companies’ “competitiveness,” which they imply (but rarely argue directly) would redound to the benefit of most American families.
What this report finds: We find their central argument—that U.S. corporations face high corporate taxes—to be empirically false. While U.S. statutory tax rates are higher, the effective tax rate paid by corporations is in fact roughly equivalent to the effective tax rates of our peer countries, due to loopholes in the U.S. tax code. Further, we find that even if the effective corporate tax rate were higher (if loopholes were closed), economic theory and data do not support the idea that cutting these rates would encourage further investment in the U.S. or benefit Americans in general; we find that such cuts would primarily benefit a small number of high-income capital owners while increasing the regressivity of the tax system overall.
Recommendations: If we wish to reform corporate tax policy to benefit the vast majority of Americans—and not just a wealthy few—we should not be talking about lowering corporate tax rates or offering other tax breaks to corporations; we should instead be focusing on closing loopholes in the system that have eroded the corporate income tax base, to ensure the corporate sector is paying its appropriate share of taxes…..