The Joint Committee on Taxation has released Fairness and Tax Policy (JCX-48-15):
The Senate Committee on Finance has scheduled a public hearing on March 3, 2015, titled “Fairness in Taxation.” This document ... describes concepts of tax equity and provides data related to the current and historical distribution of income and taxes. ...
For 2015, the top 10 percent (in terms of income) of all tax returns receive 45 percent of all income and pay 82 percent of all income taxes. The top five percent of all tax returns receive 34 percent of all income and pay 71 percent of all income taxes. The top one percent of all tax returns receives 19 percent of all income and pay 49 percent of all income taxes.
Table 4, below, shows the projected distribution of income and taxes by income category for 2015 tax returns. For example, tax returns with $30,000 to $40,000 of income constitute 9.8 percent of all returns, 4.4 percent of all income, 1.8 percent of total taxes, -0.8 percent of individual income taxes, and 4.6 percent of social insurance taxes. Similarly, tax returns with $100,000 to $200,000 of income constitute 15.2 percent of all returns, 26.7 percent of all income, 20.2 percent of total taxes, 23.6 percent of individual income taxes, and 33.7 percent of social insurance taxes.
Table 4 also shows average tax rates by income category for the individual income tax, social insurance taxes, and for total taxes (including the individual income tax, social insurance taxes and excise taxes, and the corporate income tax). Note that the average tax rate reported here is the tax collected by the relevant tax, divided by total income (not only income subject to the relevant tax). The average tax rate for social insurance taxes is similar across most tax returns, ranging between 7.3 and 10.2 percent for tax returns with income below $500,000, with substantially lower average rates for those with income above $500,000. In contrast, the average tax rate under the income tax varies widely, from a negative 11.0 percent to 27.4 percent, reflecting the existence of refundable tax credits and progressive statutory rates of tax.