Income tax in the United States dates. Some states permit related corporations to file combined or consolidated returns. Most states and localities imposing income tax require estimated payments where tax exceeds certain thresholds, and require withholding tax on payment of wages. Puerto Rico is treated as a separate taxing entity from the USA; its income tax rates are set independently, and only some residents there pay federal income taxes (though everyone must pay all other federal taxes). The unincorporated territories Guam, American Samoa, and the Virgin Islands also impose income tax separately, under a "mirror" tax law based on federal income tax law. Proposals have been
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