Income tax in the United States increase complexity, irrespective of the system's flatness or lack thereof. Income tax is also levied by most U.S. states and many localities on individuals, corporations, estates, and trusts. These taxes are in addition to federal income tax and are deductible for federal tax purposes. State and local income tax rates vary from 1% to 16% of taxable income. Some state and local income tax rates are flat (single rate) and some are graduated. State and local definitions of what income is taxable vary highly. Some states incorporate the federal definitions by reference. Taxable income is defined separately and differently for
Negative income tax for the taxes drawn at the source is flat) which is positive once the income exceeds the tax exemption. If, however, the income is less than the tax exemption, the effective progressive rate actually becomes negative without any involvement by any tax authority. As for the positive progression, only very high incomes would lead to an actual tax rate which is close to the nominal flat tax rate. The tax on tax exemption also can be understood as a tax credit, which is paid back once an income has reached the level of the tax exemption. This level marks the