How long do I have to file an IL-1040-X to report a federal change?

If your federal change resulted in an overpayment or if you claimed a net operating loss (NOL) carryback, you should not file Form IL-1040-X until you receive a federal finalization notification from the IRS stating that they have accepted your change either by paying a refund or by final assessment, agreement, or judgment. If your federal change increases your Illinois tax, you must file a Form IL-1040-X, Amended Individual Income Tax Return and pay any additional tax within 120 days of the federal finalization date (the date you filed your U.S. Form 1040-X and paid the tax due), or you may be assessed a late-payment penalty.

If you have additional inquiries, you may submit them to the Questions, Comments, or Request form.