Ind. Code § 8-1-6-7

Sec. 7. One quarter (1/4) of the annual fee imposed under section 4 of this chapter shall be paid to the commission on or before the first day of July of the year in which the fee is imposed and one quarter (1/4) on the first day of each of the months of October, January, and April following immediately thereafter; or the entire amount of such fee may, at the election of the utility, be paid in full on or before July 1 of such year.