Sec. 4. (a) If a holder's state tax credit exceeds the holder's state tax liability for the taxable year, the excess may be carried forward for up to nine (9) consecutive taxable years immediately following the first taxable year of the holder's state tax credit period and may be used to reduce the holder's state tax liability during those taxable years. Only the unused part of a state tax credit may be carried forward and used in a subsequent taxable year.
(b) The holder of a state tax credit is not entitled to a carryback or refund of any unused credit.