Texas Government Code - GOV'T § 403.220. Credit or Refund

(a) If the final judgment in a suit under this subchapter maintains the right of the applicant for a temporary or permanent injunction to prevent the collection of the tax or fee, the comptroller shall credit the amount of the tax or fee, with the interest on that amount, against any other amount finally determined to be due to the state from the applicant according to information in the custody of the comptroller and shall refund the remainder to the applicant.  The credit or refund shall be made as soon as practicable on or after September 1 of the first year of the first state biennium that begins after the date of the final judgment.

(b) For purposes of this section, the interest to be paid on a refund of a tax or fee is an amount equal to the amount of interest that would have been earned by the tax or fee if the tax or fee had been paid into the suspense account of the comptroller.