Ind. Code § 30-4-5-20
The provisions of 30-4-5-18 shall be effective as to corporations to which such section applies in accordance with the following subsections (a) and (b):
(b) With respect to each such corporation organized before January 1, 1970, the provisions of 30-4-5-18 shall be effective during taxable years commencing after December 31, 1971.
Formerly: Acts 1971, P.L.416, SEC.6.