(7) Service in a combat zone, etc., see section 7508.

(8) Claims against transferees and fiduciaries, see chapter 71.

(9) Assessments to recover excessive amounts paid under section 6420 (relating to gasoline used on farms), 6421 (relating to gasoline used for certain nonhighway purposes or by local transit systems), 6424 (relating to lubricating oil used for certain nontaxable purposes), or 6427 (relating to fuels not used for taxable purposes) and assessments of civil penalties under section 6675 for excessive claims under section 6420, 6421, 6424, or 6427, see section 6206.

(10) Assessment and collection of interest, see section 6601 (g).

(11) Assessment of civil penalties under section 6694 or 6695, see section 6696(d) (1).

(Aug. 16, 1954, c. 736, 68A Stat. 807; Apr. 2, 1956, c. 160, § 4(d), 70 Stat. 91; June 29, 1956, c. 462, Title II, § 208 (e) (5), 70 Stat. 397; Sept. 2, 1958, Pub. L. 85-866, Title I, § 84(b), 72 Stat. 1664; Feb. 26, 1964, Pub. L. 88-272, Title I, § 112(d) (2), 78 Stat. 24; Dec. 30, 1969, Pub. L. 91–172, Title II, § 213(c) (3), 83 Stat. 572; Dec. 31, 1970, Pub. L. 91-614, Title I, § 101 (d) (2), 84 Stat. 1837; Jan. 3, 1975, Pub. L. 93-625, § 7(d) (4), 88 Stat. 2115; Oct. 4, 1976, Pub. L. 94-455, Title XII, § 1203 (h) (2), Title XIX, §§ 1901 (b)(31) (D), (36) (C), (37) (D), (39) (B), 1906(a)(32), 90 Stat. 1694, 1800, 1802, 1803, 1829; May 23, 1977, Pub. L. 95–30, Title I, § 101 (d) (16), 91 Stat. 134; Nov. 6, 1978, Pub. L. 95-600, Title IV, § 405 (c) (6), Title VII, § 703(j) (10), 92 Stat. 2871, 2942; Nov. 9, 1978, Pub. L. 95–618, Title II, § 233(b) (2) (D), 92 Stat. 3191.)

Sec. 6511. Limitations on credit or refund.

(a) Period of limitation on filing claim

Claim for credit or refund of an overpayment of any tax imposed by this title in respect of which tax the taxpayer is required to file a return shall be filed by the taxpayer within 3 years from the time the return was filed or 2 years from the time the tax was paid, whichever of such periods expires the later, or if no return was filed by the taxpayer, within 2 years from the time the tax was paid. Claim for credit or refund of an overpayment of any tax imposed by this title which is required to be paid by means of a stamp shall be filed by the taxpayer within 3 years from the time the tax was paid. (b) Limitation on allowance of credits and refunds

(1) FILING OF CLAIM WITHIN PRESCRIBED PERIOD.-No credit or refund shall be allowed or made after the expiration of the period of limitation prescribed in subsection (a) for the filing of a claim for credit or refund, unless a claim for credit or refund is filed by the taxpayer within such period.

(2) LIMIT ON AMOUNT OF CREDIT OR REFUND.—

(A) Limit where claim filed within 3-year period. If the claim was filed by the taxpayer during the 3-year period prescribed in

subsection (a), the amount of the credit or refund shall not exceed the portion of the tax paid within the period, immediately preceding the filing of the claim, equal to 3 years plus the period of any extension of time for filing the return. If the tax was required to be paid by means of a stamp, the amount of the credit or refund shall not exceed the portion of the tax paid within the 3 years immediately preceding the filing of the claim.

(B) Limit where claim not filed within 3-year period.-If the claim was not filed within such 3-year period, the amount of the credit or refund shall not exceed the portion of the tax paid during the 2 years immediately preceding the filing of the claim.

(C) Limit if no claim filed. If no claim was filed, the credit or refund shall not exceed the amount which would be allowable under subparagraph (A) or (B), as the case may be, if claim was filed on the date the credit or refund is allowed.

(c) Special rules applicable in case of extension of time by agreement If an agreement under the provisions of section 6501 (c) (4) extending the period for assessment of a tax imposed by this title is made within the period prescribed in subsection (a) for the filing of a claim for credit or refund

(1) Time for FILING CLAIM.- -The period for filing claim for credit or refund or for making credit or refund if no claim is filed, provided in subsections (a) and (b)(1), shall not expire prior to 6 months after the expiration of the period within which an assessment may be made pursuant to the agreement or any extension thereof under section 6501 (c) (4).

(2) Limit on AMOUNT.—If a claim is filed, or a credit or refund is allowed when no claim was filed, after the execution of the agreement and within 6 months after the expiration of the period within which an assessment may be made pursuant to the agreement or any extension thereof, the amount of the credit or refund shall not exceed the portion of the tax paid after the execution of the agreement and before the filing of the claim or the making of the credit or refund, as the case may be, plus the portion of the tax paid within the period which would be applicable under subsection (b) (2) if a claim had been filed on the date the agreement was executed.

(3) CLAIMS NOT SUBJECT TO SPECIAL RULE.-This subsection shall not apply in the case of a claim filed, or credit or refund allowed if no claim is filed, either—

(A) prior to the execution of the agreement or

(B) more than 6 months after the expiration of the period within which an assessment may be made pursuant to the agreement or any extension thereof.

(d) Special rules applicable to income taxes

(1) SEVEN-YEAR PERIOD OF LIMITATION WITH Respect to bad DEBTS AND WORTHLESS SECURITIES.-If the claim for credit or refund relates to an overpayment of tax imposed by subtitle A on account of—

(A) The deductibility by the taxpayer, under section 166 or section 832 (c), of a debt as a debt which became worthless, or, under section 165 (g), of a loss from worthlessness of a security, or

(B) The effect that the deductibility of a debt or loss described in subparagraph (A) has on the application to the taxpayer of a

carryover,

in lieu of the 3-year period of limitation prescribed in subsection (a), the period shall be 7 years from the date prescribed by law for filing the return for the year with respect to which the claim is made. If the claim for credit or refund relates to an overpayment on account of the effect that the deductibility of such a debt or loss has on the application to the taxpayer of a carryback, the period shall be either 7 years from the date prescribed by law for filing the return for the year of the net operating loss which results in such carryback or the period prescribed in paragraph (2) of this subsection, whichever expires the later. In the case of a claim described in this paragraph the amount of the credit or refund may exceed the portion of the tax paid within the period prescribed in subsection (b) (2) or (c), whichever is applicable, to the extent of the amount of the overpayment attributable to the deductibility of items described in this paragraph.

(2) SPECIAL PERIOD OF LIMITATION WITH RESPECT TO NET OPERATING

LOSS OR CAPITAL LOSS CARRYBACKS.—

(A) Period of limitation.-If the claim for credit or refund relates to an overpayment attributable to a net operating loss carryback or a capital loss carryback, in lieu of the 3-year period of limitation prescribed in subsection (a), the period shall be that period which ends 3 years after the time prescribed by law for filing the return (including extensions thereof) for the taxable year of the net operating loss or net capital loss which results in such carryback, or the period prescribed in subsection (c) in respect of such taxable year, whichever expires later; except that with respect to an overpayment attributable to the creation of, or an increase in a net operating loss carryback as a result of the elimination of excessive profits by a renegotiation (as defined in section 1481(a) (1) (A)), the period shall not expire before the expiration of the 12th month following the month in which the agreement or order for the elimination of such excessive profits becomes final. In the case of such a claim, the amount of the credit or refund may exceed the portion of the tax paid within the period provided in subsection (b) (2) or (c), whichever is applicable, to the extent of the amount of the overpayment attributable to such carryback.

(B) Applicable rules.

(i) If the allowance of a credit or refund of an overpayment of tax attributable to a net operating loss carryback or a capital loss carryback is otherwise prevented by the operation of any law or rule of law other than section 7122, relating to compromises, such credit or refund may be allowed or made, if claim therefor is filed within the period provided in subparagraph (A) of this paragraph. If the allowance of an application, credit, or refund of a decrease in tax determined under section 6411(b) is otherwise prevented by the operation of any law or rule of law other than section 7122, such application, credit, or refund may be allowed or made if application for a tentative carryback adjustment is made within the period provided in section 6411(a). In the case of any such claim for credit or refund or any such application for a tentative carryback adjustment, the determination by any court, including the Tax Court, in any proceeding in which the decision of the court has become final, shall be conclusive except with respect to the net operating loss deduction, and the effect of such deduction, or with respect to the determination of a short-term capital loss, and the effect of such short-term capital loss, to the extent that such deduction or short-term capital loss is affected by a carryback which was not an issue in such proceeding.

(ii) A claim for credit or refund for a computation year (as defined in section 1302 (c) (1)) shall be determined to relate to an overpayment attributable to a net operating loss carryback or a capital loss carryback, as the case may be, when such carryback relates to any base period year (as defined in section 1302 (c) (3)).

(3) SPECIAL Rules relating to FOREIGN TAX CREDIT.—

(A) Special period of limitation with respect to foreign taxes paid or accrued. If the claim for credit or refund relates to an overpayment attributable to any taxes paid or accrued to any foreign country or to any possession of the United States for which credit is allowed against the tax omposed by subtitle A in accordance with the provisions of section 901 or the provisions of any treaty to which the United States is a party, in lieu of the 3-year period of limitation prescribed in subsection (a), the period shall be 10 years from the date prescribed by law for filing the return for the year with respect to which the claim is made.

(B) Exception in the case of foreign taxes paid or accrued.— In the case of a claim described in subparagraph (A), the amount of the credit or refund may exceed the portion of the tax paid within the period provided in subsection (b) or (c), whichever

is applicable, to the extent of the amount of overpayment attributable to the allowance of a credit for the taxes described in sub

paragraph (A).

(4) SPECIAL PERIOD OF LIMITATION WITH RESPECT TO INVESTMENT

CARRYBACKS.

(A) Period of limitation.-If the claim for credit or refund relates to an overpayment attributable to a credit carryback, in lieu of the 3-year period of limitation prescribed in subsection (a), the period shall be that period which ends 3 years after the time prescribed by law for filing the return (including extensions thereof) for the taxable year of the unused credit which results in such carryback (or, with respect to any portion of a credit carryback from a taxable year attributable to a net operating loss carryback, capital loss carryback, or other credit carryback from a subsequent taxable year, the period shall be that period which ends 3 years after the time prescribed by law for filing the return, including extensions thereof, for such subsequent taxable year) or the period prescribed in subsection (c) in respect of such taxable year, whichever expires later. In the case of such a claim, the amount of the credit or refund may exceed the portion of the tax paid within the period provided in subsection (b) (2) or (c), whichever is applicable, to the extent of the amount of the overpayment attributable to such carryback.

(B) Applicable rules.—If the allowance of a credit or refund of an overpayment of tax attributable to a credit carryback is otherwise prevented by the operation of any law or rule of law other than section 7122, relating to compromises, such credit or refund may be allowed or made, if claim therefor is filed within the period provided in subparagraph (A) of this paragraph. In the case of any such claim for credit or refund, the determination by any court, including the Tax Court, in any proceeding in which the decision of the court has become final, shall not be conclusive with respect to any credit, and the effect of such credit, to the extent that such credit is affected by a credit carryback which was not in issue in such proceeding.

(C) Credit carryback defined. For purposes of this paragraph, the term "credit carryback” means any investment credit carryback, work incentive program credit carryback and new employee credit carryback.

(5) SPECIAL PERIOD OF LIMITATION WITH RESPECT TO SELF-EMPLOYMENT TAX IN CERTAIN CASES. -If the claim for credit or refund relates to an overpayment of the tax imposed by chapter 2 (relating to the tax on self-employment income) attributable to an agreement, or modification of an agreement, made pursuant to section 218 of the Social Security Act (relating to coverage of State and local employees), and if the allowance of a credit or refund of such overpayment is otherwise