Corporate Tax in The United States - State and Local Income Taxes

State and Local Income Taxes

Nearly all of the states and some localities impose a tax on corporation income. The rules for determining this tax vary widely from state to state. Many of the states compute taxable income with reference to federal taxable income, with specific modifications. The states do not allow a tax deduction for income taxes, whether federal or state. Further, most states deny tax exemption for interest income that is tax exempt at the federal level.

Most states tax domestic and foreign corporations on taxable income derived from business activities apportioned to the state on a formulary basis. Many states apply a "throw back" concept to tax domestic corporations on income not taxed by other states. Tax treaties do not apply to state taxes.

Under the U.S. constitution, states are prohibited from taxing income of a resident of another state unless the connection with the taxing state reach a certain level (called “nexus”). Most states do not tax non-business income of out of state corporations. Since the tax must be fairly apportioned, the states and localities compute income of out of state corporations (including those in foreign countries) taxable in the state by applying formulary apportionment to the total business taxable income of the corporation. Many states use a formula based on ratios of property, payroll, and sales within the state to those items outside the state.