(a)(1) Any company believing that it has overpaid any taxes imposed under § 12-587 may file a claim for refund in writing with the commissioner within three years from the due date for which such overpayment was made, stating the specific grounds upon which the claim is founded. Failure to file a claim within the time prescribed in this section constitutes a waiver of any demand against the state on account of overpayment. Not later than ninety days following receipt of such claim for refund the commissioner shall determine whether such claim is valid and if so, said commissioner shall notify the State Comptroller of the amount of such refund and the State Comptroller shall draw an order on the State Treasurer in the amount thereof for payment to such company. If the commissioner determines that such claim is not valid, either in whole or in part, he shall mail notice of the proposed disallowance to the claimant, which notice shall set forth briefly the commissioner’s findings of fact and the basis of disallowance in each case decided in whole or in part adversely to the claimant. Sixty days after the date on which it is mailed, a notice of proposed disallowance shall constitute a final disallowance except only for such amounts as to which the claimant has filed, as provided in subdivision (2) of this subsection, a written protest with the commissioner.

(2) On or before the sixtieth day after the mailing of the proposed disallowance, the claimant may file with the commissioner a written protest against the proposed disallowance in which the claimant sets forth the grounds on which the protest is based. If a protest is filed, the commissioner shall reconsider the proposed disallowance and, if the claimant has so requested, may grant or deny the claimant or the claimant’s authorized representatives an oral hearing.

(3) The commissioner shall mail notice of his determination to the claimant, which notice shall set forth briefly the commissioner’s findings of fact and the basis of decision in each case decided in whole or in part adversely to the claimant.

(4) The action of the commissioner on the claimant’s protest shall be final upon the expiration of one month from the date on which he mails notice of his action to the claimant unless within such period the claimant seeks judicial review of the commissioner’s determination pursuant to § 12-597.

(b) (1) To any refund granted as a result of overpayments of any taxes imposed under § 12-587, except refunds due because of any intentional overpayment, there shall be added interest at the rate of two-thirds of one per cent for each month or fraction of a month, as provided in subdivisions (2) and (3) of this subsection.

(2) In case of such overpayment pursuant to a tax return, no interest shall be allowed or paid under this subsection on such overpayment for any month or fraction thereof prior to (A) the ninety-first day after the last day prescribed for filing the tax return associated with such overpayment, or (B) the ninety-first day after the date such return was filed, whichever is later.

(3) In case of such overpayment pursuant to an amended tax return, no interest shall be allowed or paid under this subsection on such overpayment for any month or fraction thereof prior to the ninety-first day after the date such amended tax return was filed.