For individuals, trusts, and estates, the Illinois Income Tax is increasing from 3.75 percent (.0375) to 4.95 percent (.0495).
For corporations (excluding S corporations), the Illinois Income Tax is increasing from 5.25 percent (.0525) to 7 percent (.07).
When are the new income tax rates effective?
The new income tax rates are effective for income received on or after July 1, 2017.
The following link is to the bulletin from IDOR: