Illinois DOR Issues Instructions for Form IL-1120-X, Amended Corporation Income and Replacement Tax Return

The Illinois Department of Revenue Dec. 1 issued instructions for 2020 Form IL-1120-X, Amended Corporation Income and Replacement Tax Return. Corporate income taxpayers should file the form to amend a previously filed Form IL-1120, Corporation Income and Replacement Tax Return, or Form IL-1120-X, for changes that affect items used to figure their Illinois net income, net loss, or credits. The instructions include information on: 1) changing the return before the extended due date expires; 2) amending an original Form IL-1120 due to multiple federal adjustments; 3) amending returns involving unitary filing and net loss deduction; 4) penalties and interest and ...