Why Some Tax Units Pay No Income Tax

http://www.taxpolicycenter.org/UploadedPDF/1001547-Why-No-Income-Tax.pdf

About 46 percent of American households will pay no federal individual income tax in 2011,
roughly half of them because of structural features of the income tax that provide basic
exemptions for subsistence level income and for dependents. The other half are nontaxable
because tax expenditures— special provisions of the tax code that benefit selected taxpayers or
activities—wipe out tax liabilities and, in the case of refundable credits, result in net payments
from the government. Most important of those tax expenditures are provisions that benefit senior
citizens and low-income working families with children. While those factors particularly affect
lower-income households, different provisions eliminate taxes for other households. Itemized
deductions and credits for children and education are more important for middle-income
households, while the relatively few high-income nontaxable households benefit most from
above-the-line and itemized deductions and reduced tax rates on capital gains and dividends.