Interest Generally Allowable Underpayment interest accrues on unpaid excise taxes, unless otherwise provided, from due date of the return to date paid. Overpayment interest accrues, unless otherwise provided, from the due date of the return to date paid. Special Interest Rules Airline Ticket Tax Refunds. Interest is allowable under section 6402.
Interest is accrued from the claim received date to the refund schedule date.
There are additional rules that treat certain events as overpayments but restrict the interest on the payments. These rules are provided in the remainder of this chapter. Chemicals Section 4662 treats as an overpayment any tax paid on a taxable chemical that is exported, used as feedstock, and, in some cases, used as fertilizer or animal feed. Internal Revenue Manual Hndbk.