On December 22, 2017, Public Law 115-97, the Tax Cuts and Jobs Act (the Act) was signed into law. This Act will impact Illinois' income tax base and therefore the state's income tax revenue. The Department has analyzed the Act based on current Illinois law, federal law, and Internal Revenue Service (IRS) rulings and interpretations and issued an "Explanation of the Impact on Illinois Tax Revenue Resulting from the Federal Tax Cuts and Jobs Act."

A copy of the explanation can be found here