What if I want to use an Illinois Net Loss Deduction (NLD) but failed to file the loss year return?

You must file the return that generates the loss prior to claiming the loss. The return that generates the loss can be filed at any time for purposes of establishing the loss, but no credit or refund will be issued on a return that is filed three (3) or more years past the extended due date. If you file your loss return three (3) years or more past the extended due date of the return, you will be entitled to claim the loss for NLD purposes, but you will not be entitled to a refund or credit of any overpayment calculated on the loss return.