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
Working Tax Credit Prime Minister Tony Blair also apologised to Parliament over the incident. The Working Tax Credit scheme was subject to much criticism, particularly in the wake of the difficulties surrounding its implementation. Criticism focused on the way that credits are calculated on an annual basis, leading to overpayment, followed by large demands for repayment, which those on low income may find difficult to meet. David Harker, chief executive of Citizens Advice, commented "This is an untenable system. An annualised system doesn't provide the stability of income required by low income families." In addition, the scheme was accused of being over-complicated and