Income tax return for taxation also vary, making comparisons all the more difficult. Countries that tax income generally use one of two systems: territorial or residential. In the territorial system, only local income – income from a source inside the country – is taxed. In the residential system, residents of the country are taxed on their worldwide (local and foreign) income, while nonresidents are taxed only on their local income. In addition, a very small number of countries, notably the United States, also tax their nonresident citizens on worldwide income. Countries with a residential system of taxation usually allow deductions or credits
Dual income tax Dual income tax The dual income tax system levies a proportional tax rate on all net income (capital, wage and pension income less deductions) combined with progressive tax rates on gross labour and pension income. This implies that labour income is taxed at higher rates than capital income, and that the value of the tax allowances is independent of the income level. The dual income tax system deliberately moves away from the comprehensive income tax (global income tax) system which taxes all or most (cash) income less deductions (net income) according to the same rate schedule. The dual income tax