Indiana Code Title 5. State and Local Administration § 5-28-21-17

Sec. 17. In order to establish a rate of interest for a loan under this chapter, the corporation shall select a nationally recognized index of municipal bond averages and a date not less than one (1) month nor more than two (2) months before the granting of the loan.  The rate of interest on the loan must be one percent (1%) less than the average published on the date closest to the selected date by the selected nationally recognized index, rounded to the next lowest whole percent.  The corporation may determine that the rounding down should be to a fraction of a percent that is a multiple of either one-tenth of one percent (0.1%) or one-fourth of one percent (0.25%).