Distributional Effects of Individual Income Tax Expenditures: An Update

This paper provides estimates of the total cost of non-business tax expenditures claimed on individual tax returns, taking account of interactions among provisions, and of their distributional effects among income groups. We estimate that non-business tax expenditures reduced tax liability by $1.17 trillion in 2015. Interactions among provisions make the revenue cost of all tax expenditures about 6 percent larger than the sum of the costs of the separate provisions. We also find that tax expenditures, on average, reduce taxes as a share of income more for upper-income than for lower-income taxpayers. Tax expenditures reduce tax liability by over 13.4 percent of income for taxpayers in the top 1 percent of the income distribution and by much smaller amounts in other income groups.