Net operating and business loss carry-forward and carry-back.
(a)#
No offset of Wisconsin income may be made under s. 71.05 (8) (b) 1., 71.26 (4) (a), or 71.45 (4) (a) unless the incurred loss was computed on a return that was filed within 4 years of the unextended due date for filing the original return for the taxable year in which the loss was incurred.
(b)#
No carry-back of a loss may be allowed under s. 71.05 (8) (b) 1. unless claimed within 4 years of the unextended due date for filing the original return for the taxable year to which the loss is carried back.