Advocates of cutting corporate tax rates frequently make their argument based on the higher statutory rate in the United States as compared with the rest of the world; they argue that cutting corporate taxes would induce large investment flows into the United States, which would create jobs or expand the taxable income base enough to raise revenue. President Barack Obama has supported a rate cut if the revenue loss can be offset with corporate base broadening. Others have urged on one hand, a revenue raising reform, and, on the other, setting deficit concerns aside. Is the U.S. tax rate higher than the rest of the world, and what does that difference imply for tax policy? The answer depends, in part, on which tax rates are being compared. Although the U.S. statutory tax rate is higher, the average effective rate is about the same, and the marginal rate on new investment is only slightly higher. The statutory rate differential is relevant for international profit shifting; effective rates are more relevant for firms' investment levels. The 13.7 percentage point differential in statutory rates (a 39.2% rate for the United States compared with 25.5% in other countries), narrows to about 9 percentage points when tax rates in the rest of the world are weighted to reflect the size of countries' economies. (The OECD rates fell by slightly over1/2 of a percentage point between 2010 and 2012) Regardless of tax differentials, could a U.S. rate cut lead to significant economic gains and revenue feedbacks? Because of the factors that constrain capital flows, estimates for a rate cut from 35% to 25% suggest a modest positive effect on wages and output: an eventual one-time increase of less than two-tenths of 1% of output. Most of this output gain is not an increase in national income because returns to capital imported from abroad belong to foreigners and the returns to U.S. investment abroad that comes back to the United States are already owned by U.S. firms. The revenue cost of such a rate cut is estimated at between $1.2 trillion and $1.5 trillion over the next 10 years. Revenue feedback effects from increased investment inflows are estimated to reduce those revenue costs by 5%-6%. Reductions in profit shifting could have larger effects, but even if profit shifting disappeared entirely, it would not likely offset revenue losses. It seems unlikely that a rate cut to 25% would significantly reduce profit shifting given these transactions are relatively costless and largely constrained by laws, enforcement, and court decisions. Both output gains and revenue offsets would be reduced if other countries responded to a U.S. rate cut by reducing their own taxes. Evidence suggests that the U.S. rate cut in the Tax Reform Act of 1986 triggered rate cuts in other countries. It is difficult, although not impossible, to design a reform to lower the corporate tax rate by 10 percentage points that is revenue neutral in the long run. Standard tax expenditures do not appear adequate for this purpose. Eliminating one of the largest provisions, accelerated depreciation, gains much more revenue in the short run than in the long run, and a long-run revenue-neutral change would increase the cost of capital. Other revisions, such as restricting foreign tax credits and interest deductibility or increasing shareholder level taxes, may be required. This publication focuses on the global issues relating to tax rate differentials between the United States and other countries. It provides tax rate comparisons; discusses policy implications, including the effect of a corporate rate cut on revenue, output, and national welfare; and discusses the outlook for and consequences of a revenue neutral corporate tax reform.