Ind. Code § 22-8-1.1-48
(c) The annual tax payment is due and payable on or before May 1 of each year in which the tax is imposed.
Formerly: Acts 1971, P.L.356, SEC.1; Acts 1975, P.L.255, SEC.4. As amended by Acts 1982, P.L.95, SEC.11; P.L.37-1985, SEC.42; P.L.34-1988, SEC.17; P.L.32-2008, SEC.6; P.L.76-2012, SEC.3.