Income tax in the United States These treaties reduce the chance of double taxation by allowing each country to fully tax its citizens and residents and reducing the amount the other country can tax them. Generally the treaties provide for reduced rates of tax on investment income and limits as to which business income can be taxed. The treaties each define which taxpayers can benefit from the treaty. The United States social insurance system is funded by a tax similar to an income tax. Social Security tax of 6.2% is imposed on wages paid to employees. The tax is imposed on both the employer and the
State income tax particularly with respect to partnerships. Most states require taxpayers to make quarterly payments of tax not expected to be satisfied by withholding tax. All states impose penalties for failing to file required tax returns and/or pay tax when due. In addition, all states impose interest charges on late payments of tax, and generally also on additional taxes due upon adjustment by the taxing authority. Forty-three states impose a tax on the income of individuals, sometimes referred to as personal income tax. State income tax rates vary widely from state to state. The states imposing an income tax on individuals tax