Article I of the United States Constitution created and empowered our legislative branch of government. The United States Congress leads the legislative branch. Congress includes both the House of Representatives and the Senate. Generally speaking, Congress makes our laws.
Income Tax returns and schedules. The Illinois Business Income Tax rate for tax years. ending on or after December 31, 2015, is 5.25 percent. (.0525) for taxpayers taxed as corporations, and 3.75. percent (.0375) for taxpayers taxed as trusts or estates. The instructions for overpayments to be carried forward.
Illinoisâs corporate income tax is charged at a flat rate of 7% of federal taxable income, with adjustments. Returns are due on the 15th day of the 3rd month after the end of the corporationâs tax year. For corporations with tax years following the calendar year, this means March 15th. (For the sake of comparison, the Illinois personal income tax rate is a flat 5% of federal adjusted gross income, with adjustments.)