Indiana Code Title 6. Taxation § 6-3.1-34.6-13

Sec. 13. (a) If the amount of the credit determined under this chapter for a person in a taxable year exceeds the person's state tax liability for that taxable year, the person may carry over the excess to the following taxable years.  The amount of the credit carryover from a taxable year shall be reduced to the extent that the carryover is used by the person to obtain a credit under this chapter for any subsequent taxable year.  A credit may not be carried forward for more than six (6) taxable years following the taxable year in which the person is first entitled to claim the credit.

(b) A person is not entitled to a carryback or refund of any unused credit.