The Congressional Budget Office (CBO) looks at corporate income taxes

The top federal statutory corporate income tax rate in the U.S. is 35%. With state taxes, the top rate averages 39.1%. President Trump and House Republicans have vowed to reduce the top corporate tax to 15%-20%. The CBO studied corporate rates in 2012 and found the U.S. had the highest rate among G20 countries. It released an updated report showing that some countries have lowered rates since then. For example, Japan’s top 2015 statutory corporate tax rate was 32.1%, 5% lower than in 2012