Ind. Code § 6-3-8.1-2

Sec. 2. Notwithstanding the repeal of IC 6-3-8-5 by P.L.192-2002(ss), the provisions of IC 6-3-8-5 (repealed) apply to the imposition, collection, payment, and administration of the supplemental net income tax imposed under this chapter, including the requirement related to filing the taxpayer's estimated supplemental net income tax return and paying the taxpayer's estimated supplemental net income tax liability to the department of state revenue. The taxpayer shall file a final supplemental net income tax return, in the manner prescribed by the department of state revenue, before the fifteenth day of the fourth month following the close of the taxpayer's regular taxable year, determined as if IC 6-3-8 had not been repealed by P.L.192-2002(ss).