(a) General rule. Except as otherwise provided, interest shall be allowed on any overpayment of any tax at the annual rate referred to in the regulations under section 6621 from the date of overpayment of the tax.

(b) Date of overpayment. Except as provided in section 6401(a), relating to assessment and collection after the expiration of the applicable period of limitation, there can be no overpayment of tax until the entire tax liability has been satisfied. Therefore, the dates of overpayment of any tax are the date of payment of the first amount which (when added to previous payments) is in excess of the tax liability (including any interest, addition to the tax, or additional amount) and the dates of payment of all amounts subsequently paid with respect to such tax liability. For rules relating to the determination of the date of payment in the case of an advance payment of tax, a payment of estimated tax, and a credit for income tax withholding, see paragraph (d) of this section.

(c) Examples. The application of paragraph (b) may be illustrated by the following examples:

(d) Advance payment of tax, payment of estimated tax, and credit for income tax withholding. In the case of an advance payment of tax, a payment of estimated income tax, or a credit for income tax withholding, the provisions of section 6513 (except the provisions of subsection (c) thereof), applicable in determining the date of payment of tax for purposes of the period of limitations on credit or refund, shall apply in determining the date of overpayment for purposes of computing interest thereon.

(e) Refund of income tax caused by carryback. If any overpayment of tax imposed by subtitle A of the Code results from the carryback of a net operating loss, a net capital loss, an investment credit, or a work incentive (WIN) credit, such overpayment, for purposes of this section, shall be deemed not to have been made prior to the end of the taxable year in which the loss or credit arises, or, with respect to any portion of an investment credit carryback or a WIN credit carryback from a taxable year attributable to a net operating loss carryback or a capital loss carryback from a subsequent taxable year, such overpayment shall be deemed not to have been made prior to the close of such subsequent taxable year.

(f) Refund of income tax caused by carryback of foreign taxes. For purposes of paragraph (a) of this section, any overpayment of tax resulting from a carryback of tax paid or accrued to foreign countries or possessions of the United States shall be deemed not to have been paid or accrued before the close of the taxable year under subtitle F of the Code in which such taxes were in fact paid or accrued.

(g) Period for which interest allowable in case of refunds. If an overpayment of tax is refunded, interest shall be allowed from the date of the overpayment to a date determined by the district director or the director of the regional service center, which shall be not more than 30 days prior to the date of the refund check. The acceptance of a refund check shall not deprive the taxpayer of the right to make a claim for any additional overpayment and interest thereon, provided the claim is made within the applicable period of limitation. However, if a taxpayer does not accept a refund check, no additional interest on the amount of the overpayment included in such check shall be allowed.

(h) Period for which interest allowable in case of credits—(1) General rule. If an overpayment of tax is credited, interest shall be allowed from the date of overpayment to the due date (as determined under subparagraph (2) of this paragraph (h)) of the amount against which such overpayment is credited.

(2) Determination of due date—(i) In general. The term “due date”, as used in this section, means the last day fixed by law or regulations for the payment of the tax (determined without regard to any extension of time), and not the date on which the district director or the director of the regional service center makes demand for the payment of the tax. Therefore, the due date of a tax (other than an additional assessment subject to the special rule provided by subdivision (iv) of this subparagraph) is the date fixed for the payment of the tax or the several installments thereof.

(ii) Tax payable in installments—(a) In general. In the case of a credit against a tax, where the taxpayer had properly elected to pay the tax in installments, the due date is the date prescribed for the payment of the installment against which the credit is applied.

(b) Delinquent installment. If the taxpayer is delinquent in payment of an installment of tax and a notice and demand has been issued for the payment of the delinquent installment and the remaining installments, the due date of each remaining installment shall then be the date of such notice and demand.

(iii) Tax or installment not yet due. If a taxpayer agrees to the crediting of an overpayment against tax or an installment of tax and the schedule of allowance is signed prior to the date on which such tax or installment would otherwise become due, then the due date of such tax or installment shall be the date on which such schedule is signed.

(iv) Additional assessment satisfied by credit before January 1, 1958. In the case of a credit made before January 1, 1958, against an additional assessment, the due date of the tax satisfied by the credit is the date the additional assessment was made. For purposes of this subdivision, the term “additional assessment” means a further assessment of a tax of the same character previously paid in part, and includes the assessment of a deficiency as defined in section 6211.

(v) Interest. In the case of a credit against interest that accrues for any period ending prior to January 1, 1983, the due date is the earlier of the date of assessment of such interest or December 31, 1982. In the case of a credit against interest that accrues for any period beginning on or after December 31, 1982, such interest is due as it economically accrues on a daily basis, rather than when it is assessed.

(vi) Additional amount, addition to the tax, or assessable penalty. In the case of a credit against an additional amount, addition to the tax, or assessable penalty, the due date is the earlier of the date of assessment or the date from which such amount would bear interest if not satisfied by payment or credit.

(vii) Estimated income tax for succeeding year. If the taxpayer elects to have all or part of the overpayment shown by his return applied to his estimated tax for his succeeding taxable year, no interest shall be allowed on such portion of the overpayment credited and such amount shall be applied as a payment on account of the estimated tax for such year or the installments thereof.

(i) [Reserved]

(j) Refund of overpayment. No interest shall be allowed on any overpayment of tax imposed by subtitle A of the Code if such overpayment is refunded—

(1) In the case of a return filed on or before the last date prescribed for filing the return of such tax (determined without regard to any extension of time for filing such return), within 45 days after such last date, or

(2) After December 17, 1966, in the case of a return filed after the last day prescribed for filing the return, within 45 days after the date on which the return is filed.

However, in the case of any overpayment of tax by an individual (other than an estate or trust and other than a nonresident alien individual) for a taxable year beginning in 1974, “60 days” shall be substituted for “45 days” each place it appears in this paragraph.

(k) Effective date. Paragraphs (h)(2)(v) and (h)(2)(vi) of this section are effective for credits made on or after August 25, 1992.

[32 FR 15241, Nov. 3, 1967, as amended by T.D. 7301, 39 FR 979, Jan. 4, 1974; T.D. 7384, 40 FR 49325, Oct. 22, 1975; T.D. 7415, 41 FR 14369, Apr. 5, 1976; T.D. 8524, 59 FR 10076, Mar. 3, 1994]