Generally, the due date of a franchise and excise tax return is the 15th day of the fourth month following the end of the tax period. For example, a return for the tax period January 1 through February 12 should be filed by June 15. Returns that are based on a 52-53-week year are due on or before the 15th day of the fourth month following the end of the month closest to the 52-53 week year end.
Reference: Tenn. Code Ann. § 67-4-2015(a).