
From the U.S. Code Online via GPO Access
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[Laws in effect as of January 2, 2001]
[Document not affected by Public Laws enacted between
  January 2, 2001 and January 28, 2002]
[CITE: 26USC6501]

 
                     TITLE 26--INTERNAL REVENUE CODE
 
                Subtitle F--Procedure and Administration
 
                         CHAPTER 66--LIMITATIONS
 
         Subchapter A--Limitations on Assessment and Collection
 
Sec. 6501. Limitations on assessment and collection


(a) General rule

    Except as otherwise provided in this section, the amount of any tax 
imposed by this title shall be assessed within 3 years after the return 
was filed (whether or not such return was filed on or after the date 
prescribed) or, if the tax is payable by stamp, at any time after such 
tax became due and before the expiration of 3 years after the date on 
which any part of such tax was paid, and no proceeding in court without 
assessment for the collection of such tax shall be begun after the 
expiration of such period. For purposes of this chapter, the term 
``return'' means the return required to be filed by the taxpayer (and 
does not include a return of any person from whom the taxpayer has 
received an item of income, gain, loss, deduction, or credit).

(b) Time return deemed filed

                          (1) Early return

        For purposes of this section, a return of tax imposed by this 
    title, except tax imposed by chapter 3, 21, or 24, filed before the 
    last day prescribed by law or by regulations promulgated pursuant to 
    law for the filing thereof, shall be considered as filed on such 
    last day.

     (2) Return of certain employment taxes and tax imposed by 
                                  chapter 3

        For purposes of this section, if a return of tax imposed by 
    chapter 3, 21, or 24 for any period ending with or within a calendar 
    year is filed before April 15 of the succeeding calendar year, such 
    return shall be considered filed on April 15 of such calendar year.

                  (3) Return executed by Secretary

        Notwithstanding the provisions of paragraph (2) of section 
    6020(b), the execution of a return by the Secretary pursuant to the 
    authority conferred by such section shall not start the running of 
    the period of limitations on assessment and collection.

                     (4) Return of excise taxes

        For purposes of this section, the filing of a return for a 
    specified period on which an entry has been made with respect to a 
    tax imposed under a provision of subtitle D (including a return on 
    which an entry has been made showing no liability for such tax for 
    such period) shall constitute the filing of a return of all amounts 
    of such tax which, if properly paid, would be required to be 
    reported on such return for such period.

(c) Exceptions

                          (1) False return

        In the case of a false or fraudulent return with the intent to 
    evade tax, the tax may be assessed, or a proceeding in court for 
    collection of such tax may be begun without assessment, at any time.

                  (2) Willful attempt to evade tax

        In case of a willful attempt in any manner to defeat or evade 
    tax imposed by this title (other than tax imposed by subtitle A or 
    B), the tax may be assessed, or a proceeding in court for the 
    collection of such tax may be begun without assessment, at any time.

                            (3) No return

        In the case of failure to file a return, the tax may be 
    assessed, or a proceeding in court for the collection of such tax 
    may be begun without assessment, at any time.

                     (4) Extension by agreement

        (A) In general

            Where, before the expiration of the time prescribed in this 
        section for the assessment of any tax imposed by this title, 
        except the estate tax provided in chapter 11, both the Secretary 
        and the taxpayer have consented in writing to its assessment 
        after such time, the tax may be assessed at any time prior to 
        the expiration of the period agreed upon. The period so agreed 
        upon may be extended by subsequent agreements in writing made 
        before the expiration of the period previously agreed upon.

        (B) Notice to taxpayer of right to refuse or limit extension

            The Secretary shall notify the taxpayer of the taxpayer's 
        right to refuse to extend the period of limitations, or to limit 
        such extension to particular issues or to a particular period of 
        time, on each occasion when the taxpayer is requested to provide 
        such consent.

      (5) Tax resulting from changes in certain income tax or 
                             estate tax credits

            For special rules applicable in cases where the adjustment 
        of certain taxes allowed as a credit against income taxes or 
        estate taxes results in additional tax, see section 905(c) 
        (relating to the foreign tax credit for income tax purposes) and 
        section 2016 (relating to taxes of foreign countries, States, 
        etc., claimed as credit against estate taxes).

            (6) Termination of private foundation status

        In the case of a tax on termination of private foundation status 
    under section 507, such tax may be assessed, or a proceeding in 
    court for the collection of such tax may be begun without 
    assessment, at any time.

            (7) Special rule for certain amended returns

        Where, within the 60-day period ending on the day on which the 
    time prescribed in this section for the assessment of any tax 
    imposed by subtitle A for any taxable year would otherwise expire, 
    the Secretary receives a written document signed by the taxpayer 
    showing that the taxpayer owes an additional amount of such tax for 
    such taxable year, the period for the assessment of such additional 
    amount shall not expire before the day 60 days after the day on 
    which the Secretary receives such document.

    (8) Failure to notify Secretary of certain foreign transfers

        In the case of any information which is required to be reported 
    to the Secretary under section 6038, 6038A, 6038B, 6046, 6046A, or 
    6048, the time for assessment of any tax imposed by this title with 
    respect to any event or period to which such information relates 
    shall not expire before the date which is 3 years after the date on 
    which the Secretary is furnished the information required to be 
    reported under such section.

          (9) Gift tax on certain gifts not shown on return

        If any gift of property the value of which (or any increase in 
    taxable gifts required under section 2701(d) which) is required to 
    be shown on a return of tax imposed by chapter 12 (without regard to 
    section 2503(b)), and is not shown on such return, any tax imposed 
    by chapter 12 on such gift may be assessed, or a proceeding in court 
    for the collection of such tax may be begun without assessment, at 
    any time. The preceding sentence shall not apply to any item which 
    is disclosed in such return, or in a statement attached to the 
    return, in a manner adequate to apprise the Secretary of the nature 
    of such item.

(d) Request for prompt assessment

    Except as otherwise provided in subsection (c), (e), or (f), in the 
case of any tax (other than the tax imposed by chapter 11 of subtitle B, 
relating to estate taxes) for which return is required in the case of a 
decedent, or by his estate during the period of administration, or by a 
corporation, the tax shall be assessed, and any proceeding in court 
without assessment for the collection of such tax shall be begun, within 
18 months after written request therefor (filed after the return is made 
and filed in such manner and such form as may be prescribed by 
regulations of the Secretary) by the executor, administrator, or other 
fiduciary representing the estate of such decedent, or by the 
corporation, but not after the expiration of 3 years after the return 
was filed. This subsection shall not apply in the case of a corporation 
unless--
        (1)(A) such written request notifies the Secretary that the 
    corporation contemplates dissolution at or before the expiration of 
    such 18-month period, (B) the dissolution is in good faith begun 
    before the expiration of such 18-month period, and (C) the 
    dissolution is completed;
        (2)(A) such written request notifies the Secretary that a 
    dissolution has in good faith been begun, and (B) the dissolution is 
    completed; or
        (3) a dissolution has been completed at the time such written 
    request is made.

(e) Substantial omission of items

    Except as otherwise provided in subsection (c)--

                          (1) Income taxes

        In the case of any tax imposed by subtitle A--

        (A) General rule

            If the taxpayer omits from gross income an amount properly 
        includible therein which is in excess of 25 percent of the 
        amount of gross income stated in the return, the tax may be 
        assessed, or a proceeding in court for the collection of such 
        tax may be begun without assessment, at any time within 6 years 
        after the return was filed. For purposes of this subparagraph--
                (i) In the case of a trade or business, the term ``gross 
            income'' means the total of the amounts received or accrued 
            from the sale of goods or services (if such amounts are 
            required to be shown on the return) prior to diminution by 
            the cost of such sales or services; and
                (ii) In determining the amount omitted from gross 
            income, there shall not be taken into account any amount 
            which is omitted from gross income stated in the return if 
            such amount is disclosed in the return, or in a statement 
            attached to the return, in a manner adequate to apprise the 
            Secretary of the nature and amount of such item.

        (B) Constructive dividends

            If the taxpayer omits from gross income an amount properly 
        includible therein under section 551(b) (relating to the 
        inclusion in the gross income of United States shareholders of 
        their distributive shares of the undistributed foreign personal 
        holding company income), the tax may be assessed, or a 
        proceeding in court for the collection of such tax may be begun 
        without assessment, at any time within 6 years after the return 
        was filed.

                      (2) Estate and gift taxes

        In the case of a return of estate tax under chapter 11 or a 
    return of gift tax under chapter 12, if the taxpayer omits from the 
    gross estate or from the total amount of the gifts made during the 
    period for which the return was filed items includible in such gross 
    estate or such total gifts, as the case may be, as exceed in amount 
    25 percent of the gross estate stated in the return or the total 
    amount of gifts stated in the return, the tax may be assessed, or a 
    proceeding in court for the collection of such tax may be begun 
    without assessment, at any time within 6 years after the return was 
    filed. In determining the items omitted from the gross estate or the 
    total gifts, there shall not be taken into account any item which is 
    omitted from the gross estate or from the total gifts stated in the 
    return if such item is disclosed in the return, or in a statement 
    attached to the return, in a manner adequate to apprise the 
    Secretary of the nature and amount of such item.

                          (3) Excise taxes

        In the case of a return of a tax imposed under a provision of 
    subtitle D, if the return omits an amount of such tax properly 
    includible thereon which exceeds 25 percent of the amount of such 
    tax reported thereon, the tax may be assessed, or a proceeding in 
    court for the collection of such tax may be begun without 
    assessment, at any time within 6 years after the return is filed. In 
    determining the amount of tax omitted on a return, there shall not 
    be taken into account any amount of tax imposed by chapter 41, 42, 
    43, or 44 which is omitted from the return if the transaction giving 
    rise to such tax is disclosed in the return, or in a statement 
    attached to the return, in a manner adequate to apprise the 
    Secretary of the existence and nature of such item.

(f) Personal holding company tax

    If a corporation which is a personal holding company for any taxable 
year fails to file with its return under chapter 1 for such year a 
schedule setting forth--
        (1) the items of gross income and adjusted ordinary gross 
    income, described in section 543, received by the corporation during 
    such year, and
        (2) the names and addresses of the individuals who owned, within 
    the meaning of section 544 (relating to rules for determining stock 
    ownership), at any time during the last half of such year more than 
    50 percent in value of the outstanding capital stock of the 
    corporation,

the personal holding company tax for such year may be assessed, or a 
proceeding in court for the collection of such tax may be begun without 
assessment, at any time within 6 years after the return for such year 
was filed.

(g) Certain income tax returns of corporations

                     (1) Trusts or partnerships

        If a taxpayer determines in good faith that it is a trust or 
    partnership and files a return as such under subtitle A, and if such 
    taxpayer is thereafter held to be a corporation for the taxable year 
    for which the return is filed, such return shall be deemed the 
    return of the corporation for purposes of this section.

                      (2) Exempt organizations

        If a taxpayer determines in good faith that it is an exempt 
    organization and files a return as such under section 6033, and if 
    such taxpayer is thereafter held to be a taxable organization for 
    the taxable year for which the return is filed, such return shall be 
    deemed the return of the organization for purposes of this section.

                              (3) DISC

        If a corporation determines in good faith that it is a DISC (as 
    defined in section 992(a)) and files a return as such under section 
    6011(c)(2) and if such corporation is thereafter held to be a 
    corporation which is not a DISC for the taxable year for which the 
    return is filed, such return shall be deemed the return of a 
    corporation which is not a DISC for purposes of this section.

(h) Net operating loss or capital loss carrybacks

    In the case of a deficiency attributable to the application to the 
taxpayer of a net operating loss carryback or a capital loss carryback 
(including deficiencies which may be assessed pursuant to the provisions 
of section 6213(b)(3)), such deficiency may be assessed at any time 
before the expiration of the period within which a deficiency for the 
taxable year of the net operating loss or net capital loss which results 
in such carryback may be assessed.

(i) Foreign tax carrybacks

    In the case of a deficiency attributable to the application to the 
taxpayer of a carryback under section 904(c) (relating to carryback and 
carryover of excess foreign taxes) or under section 907(f) (relating to 
carryback and carryover of disallowed oil and gas extraction taxes), 
such deficiency may be assessed at any time before the expiration of one 
year after the expiration of the period within which a deficiency may be 
assessed for the taxable year of the excess taxes described in section 
904(c) or 907(f) which result in such carryback.

(j) Certain credit carrybacks

                           (1) In general

        In the case of a deficiency attributable to the application to 
    the taxpayer of a credit carryback (including deficiencies which may 
    be assessed pursuant to the provisions of section 6213(b)(3)), such 
    deficiency may be assessed at any time before the expiration of the 
    period within which a deficiency for the taxable year of the unused 
    credit which results in such carryback may be assessed, 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, 
    at any time before the expiration of the period within which a 
    deficiency for such subsequent taxable year may be assessed.

                    (2) Credit carryback defined

        For purposes of this subsection, the term ``credit carryback'' 
    has the meaning given such term by section 6511(d)(4)(C).

(k) Tentative carryback adjustment assessment period

    In a case where an amount has been applied, credited, or refunded 
under section 6411 (relating to tentative carryback and refund 
adjustments) by reason of a net operating loss carryback, a capital loss 
carryback, or a credit carryback (as defined in section 6511(d)(4)(C)) 
to a prior taxable year, the period described in subsection (a) of this 
section for assessing a deficiency for such prior taxable year shall be 
extended to include the period described in subsection (h) or (j), 
whichever is applicable; except that the amount which may be assessed 
solely by reason of this subsection shall not exceed the amount so 
applied, credited, or refunded under section 6411, reduced by any amount 
which may be assessed solely by reason of subsection (h) or (j), as the 
case may be.

(l) Special rule for chapter 42 and similar taxes

                           (1) In general

        For purposes of any tax imposed by section 4912, by chapter 42 
    (other than section 4940), or by section 4975, the return referred 
    to in this section shall be the return filed by the private 
    foundation, plan, trust, or other organization (as the case may be) 
    for the year in which the act (or failure to act) giving rise to 
    liability for such tax occurred. For purposes of section 4940, such 
    return is the return filed by the private foundation for the taxable 
    year for which the tax is imposed.

    (2) Certain contributions to section 501(c)(3) organizations

        In the case of a deficiency of tax of a private foundation 
    making a contribution in the manner provided in section 4942(g)(3) 
    (relating to certain contributions to section 501(c)(3) 
    organizations) attributable to the failure of a section 501(c)(3) 
    organization to make the distribution prescribed by section 
    4942(g)(3), such deficiency may be assessed at any time before the 
    expiration of one year after the expiration of the period within 
    which a deficiency may be assessed for the taxable year with respect 
    to which the contribution was made.

       (3) Certain set-asides described in section 4942(g)(2)

        In the case of a deficiency attributable to the failure of an 
    amount set aside by a private foundation for a specific project to 
    be treated as a qualifying distribution under the provisions of 
    section 4942(g)(2)(B)(ii), such deficiency may be assessed at any 
    time before the expiration of 2 years after the expiration of the 
    period within which a deficiency may be assessed for the taxable 
    year to which the amount set aside relates.

(m) Deficiencies attributable to election of certain credits

    The period for assessing a deficiency attributable to any election 
under section 30(d)(4), 40(f), 43, 45B, 45C(d)(4), or 51(j) (or any 
revocation thereof) shall not expire before the date 1 year after the 
date on which the Secretary is notified of such election (or 
revocation).

(n) Cross references

            (1) For period of limitations for assessment and collection 
        in the case of a joint income return filed after separate 
        returns have been filed, see section 6013(b)(3) and (4).
            (2) For extension of period in the case of partnership items 
        (as defined in section 6231(a)(3)), see section 6229.
            (3) For declaratory judgment relating to treatment of items 
        other than partnership items with respect to an oversheltered 
        return, see section 6234.

(Aug. 16, 1954, ch. 736, 68A Stat. 803; Pub. L. 85-859, title I, 
Sec. 165(a), Sept. 2, 1958, 72 Stat. 1313; Pub. L. 85-866, title I, 
Secs. 80, 81, Sept. 2, 1958, 72 Stat. 1662; Pub. L. 86-69, Sec. 3(g), 
June 25, 1959, 73 Stat. 140; Pub. L. 86-780, Sec. 3(c), Sept. 14, 1960, 
74 Stat. 1013; Pub. L. 87-794, title III, Sec. 317(c), Oct. 11, 1962, 76 
Stat. 890; Pub. L. 87-834, Sec. 2(e)(1), Oct. 16, 1962, 76 Stat. 971; 
Pub. L. 87-858, Sec. 3(b)(4), Oct. 23, 1962, 76 Stat. 1137; Pub. L. 88-
272, title II, Sec. 225(k)(6), Feb. 26, 1964, 78 Stat. 94; Pub. L. 88-
571, Sec. 3(b), Sept. 2, 1964, 78 Stat. 857; Pub. L. 89-44, title VIII, 
Sec. 810(a), (b), June 21, 1965, 79 Stat. 169; Pub. L. 89-721, 
Secs. 2(f), 3(a), Nov. 2, 1966, 80 Stat. 1150, 1151; Pub. L. 89-809, 
title I, Sec. 105(f)(3), Nov. 13, 1966, 80 Stat. 1568; Pub. L. 90-225, 
Sec. 2(c), Dec. 27, 1967, 81 Stat. 731; Pub. L. 91-172, title I, 
Sec. 101(g)(1)-(3), title V, Sec. 512(e)(1), Dec. 30, 1969, 83 Stat. 
525, 639; Pub. L. 91-614, title I, Sec. 102(d)(8), Dec. 31, 1970, 84 
Stat. 1842; Pub. L. 92-178, title V, Sec. 504(c), title VI, 
Sec. 601(d)(1), (e)(2), Dec. 10, 1971, 85 Stat. 551, 558, 560; Pub. L. 
93-406, title II, Sec. 1016(a)(14), Sept. 2, 1974, 88 Stat. 930; Pub. L. 
94-455, title X, Secs. 1031(b)(5), 1035(d)(3), title XIII, 
Secs. 1302(b), 1307(d)(2)(F)(vi), title XIX, Sec. 1906(b)(13)(A), title 
XXI, Sec. 2107(g)(2)(A), Oct. 4, 1976, 90 Stat. 1623, 1633, 1714, 1728, 
1834, 1904; Pub. L. 95-30, title II, Sec. 202(d)(4)(A), (5)(B), May 23, 
1977, 91 Stat. 149, 151; Pub. L. 95-227, Sec. 4(d)(4), (5), Feb. 10, 
1978, 92 Stat. 23; Pub. L. 95-600, title II, Sec. 212(a), title III, 
Sec. 321(b)(2), title V, Sec. 504(b)(3), title VII, Secs. 701(t)(3)(A), 
703(n), (p)(2), Nov. 6, 1978, 92 Stat. 2818, 2835, 2881, 2912, 2943, 
2944; Pub. L. 95-628, Sec. 8(c)(1), Nov. 10, 1978, 92 Stat. 3631; Pub. 
L. 96-222, title I, Secs. 102(a)(2)(A), 103(a)(6)(G)(x), Apr. 1, 1980, 
94 Stat. 208, 210; Pub. L. 96-223, title I, Sec. 101(g)(1), Apr. 2, 
1980, 94 Stat. 253; Pub. L. 97-248, title IV, Sec. 402(c)(5), Sept. 3, 
1982, 96 Stat. 667; Pub. L. 98-369, div. A, title I, Secs. 131(d)(2), 
163(b)(1), title II, Sec. 211(b)(24), title III, Sec. 314(a)(3), title 
IV, Secs. 447(a), 474(r)(39), title VII, Sec. 714(p)(2)(F), title VIII, 
Sec. 801(d)(14), July 18, 1984, 98 Stat. 664, 697, 757, 787, 817, 846, 
965, 997; Pub. L. 99-514, title XVIII, Secs. 1810(g)(3), 1847(b)(12)-
(14), Oct. 22, 1986, 100 Stat. 2828, 2857; Pub. L. 100-203, title X, 
Secs. 10712(c)(2), 10714(c), Dec. 22, 1987, 101 Stat. 1330-467, 1330-
471; Pub. L. 100-418, title I, Sec. 1941(b)(2)(H), Aug. 23, 1988, 102 
Stat. 1323; Pub. L. 100-647, title I, Sec. 1008(j)(1), title IV, 
Sec. 4008(c)(2), Nov. 10, 1988, 102 Stat. 3445, 3653; Pub. L. 101-239, 
title VII, Sec. 7814(e)(2)(E), Dec. 19, 1989, 103 Stat. 2414; Pub. L. 
101-508, title XI, Secs. 11511(c)(2), 11602(b), Nov. 5, 1990, 104 Stat. 
1388-485, 1388-500; Pub. L. 104-188, title I, Secs. 1702(e)(3), 
1703(n)(8), 1704(j)(4)(B), Aug. 20, 1996, 110 Stat. 1870, 1877, 1882; 
Pub. L. 105-34, title V, Sec. 506(b), title XI, Sec. 1145(a), title XII, 
Secs. 1239(e)(2), 1284(a), title XVI, Sec. 1601(g)(2), Aug. 5, 1997, 111 
Stat. 855, 985, 1028, 1038, 1092; Pub. L. 105-206, title III, 
Sec. 3461(b), title VI, Secs. 6007(e)(2)(A), 6023(27), July 22, 1998, 
112 Stat. 764, 809, 826.)


                               Amendments

    1998--Subsec. (c)(4). Pub. L. 105-206, Sec. 3461(b), designated 
existing provisions as subpar. (A), inserted heading, and added subpar. 
(B).
    Subsec. (c)(9). Pub. L. 105-206, Sec. 6007(e)(2)(A), struck out at 
end ``The value of any item which is so disclosed may not be 
redetermined by the Secretary after the expiration of the period under 
subsection (a).''
    Subsec. (m). Pub. L. 105-206, Sec. 6023(27), substituted ``election 
under section 30(d)(4), 40(f), 43, 45B, 45C(d)(4), or 51(j) (or any'' 
for ``election under sections 30(d)(4), 40(f), 43, 45B, or 51(j) (or 
any''.
    1997--Subsec. (a). Pub. L. 105-34, Sec. 1284(a), inserted at end 
``For purposes of this chapter, the term `return' means the return 
required to be filed by the taxpayer (and does not include a return of 
any person from whom the taxpayer has received an item of income, gain, 
loss, deduction, or credit).''
    Subsec. (c)(8). Pub. L. 105-34, Sec. 1145(a), amended heading and 
text of par. (8) generally. Prior to amendment, text read as follows: 
``In the case of any tax imposed on any exchange or distribution by 
reason of subsection (a), (d), or (e) of section 367, the time for 
assessment of such tax shall not expire before the date which is 3 years 
after the date on which the Secretary is notified of such exchange or 
distribution under section 6038B(a).''
    Subsec. (c)(9). Pub. L. 105-34, Sec. 506(b), reenacted par. (9) 
heading without change and amended text of par. (9) generally. Prior to 
amendment, text read as follows: ``If any gift of property the value of 
which is determined under section 2701 or 2702 (or any increase in 
taxable gifts required under section 2701(d)) is required to be shown on 
a return of tax imposed by chapter 12 (without regard to section 
2503(b)), and is not shown on such return, any tax imposed by chapter 12 
on such gift may be assessed, or a proceeding in court for the 
collection of such tax may be begun without assessment, at any time. The 
preceding sentence shall not apply to any item not shown as a gift on 
such return if such item is disclosed in such return, or in a statement 
attached to the return, in a manner adequate to apprise the Secretary of 
the nature of such item.''
    Subsec. (m). Pub. L. 105-34, Sec. 1601(g)(2), provided that sections 
1703(n)(8) and 1704(j)(4)(B) of Pub. L. 104-188 shall be applied as if 
the reference in the directory language to the redesignation by section 
1602 referred to the redesignation by section 1702. See 1996 Amendment 
note below.
    Subsec. (n)(3). Pub. L. 105-34, Sec. 1239(e)(2), which directed the 
addition of par. (3) to subsec. (o), was executed by adding par. (3) to 
subsec. (n) to reflect the probable intent of Congress and the 
redesignation of subsec. (o) as (n) by Pub. L. 104-188, 
Sec. 1702(e)(3)(A). See 1996 Amendment note below.
    1996--Subsec. (m). Pub. L. 104-188, Sec. 1704(j)(4)(B), substituted 
``sections 30(d)(4), 40(f)'' for ``section 40(f)''. See 1997 Amendment 
note above.
    Pub. L. 104-188, Sec. 1703(n)(8), substituted ``45B, or 51(j)'' for 
``or 51(j)''. See 1997 Amendment note above.
    Pub. L. 104-188, Sec. 1702(e)(3), redesignated subsec. (n) as (m) 
and substituted ``section 40(f), 43, or 51(j)'' for ``section 40(f) or 
51(j)''.
    Pub. L. 104-188, Sec. 1702(e)(3)(A), which directed in part that 
subsec. (m) relating to deficiency attributable to election under 
section 44B, be struck out, could not be executed because subsec. (m) 
was previously repealed. See 1990 and 1988 Amendment notes for subsec. 
(m) and 1984 Amendment note for subsec. (p), below.
    Subsecs. (n), (o). Pub. L. 104-188, Sec. 1702(e)(3)(A), redesignated 
subsec. (o) as (n). Former subsec. (n) redesignated (m).
    1990--Subsec. (c)(9). Pub. L. 101-508, Sec. 11602(b), added par. 
(9).
    Subsec. (m). Pub. L. 101-508, Sec. 11511(c)(2), which directed the 
substitution of ``43 or 44B'' for ``44B'' wherever appearing in subsec. 
(m), could not be executed because subsec. (m) was repealed by Pub. L. 
100-418, Sec. 1941(b)(2)(H), and did not contain the term ``44B''. 
However, such term was contained in a prior subsec. (p) which was 
repealed by Pub. L. 98-369, Sec. 474(r)(39). See 1984 Amendment notes 
below.
    1989--Subsec. (n). Pub. L. 101-239 struck out ``, 41(h),'' after 
``section 40(f)''.
    1988--Subsec. (m). Pub. L. 100-418 struck out subsec. (m) relating 
to special rules for windfall profit tax.
    Subsec. (n). Pub. L. 100-647, Sec. 4008(c)(2), substituted ``, 
41(h), or 51(j)'' for ``or 51(j)''.
    Subsec. (o)(3). Pub. L. 100-647, Sec. 1008(j)(1), struck out par. 
(3) which read as follows: ``For extension of period in the case of 
certain contributions in aid of construction, see section 118(c).''
    1987--Subsec. (l)(1). Pub. L. 100-203, Sec. 10714(c), substituted 
``by section 4912, by chapter 42 (other than section 4940),'' for ``by 
chapter 42 (other than section 4940)''.
    Pub. L. 100-203, Sec. 10712(c)(2), substituted ``plan, trust, or 
other organization'' for ``plan, or trust''.
    1986--Subsec. (c)(8). Pub. L. 99-514, Sec. 1810(g)(3), substituted 
``exchange or distribution'' for ``exchange'' in two places, and 
``subsection (a), (d), or (e)'' for ``subsection (a) or (d)''.
    Subsecs. (k) to (p). Pub. L. 99-514, Sec. 1847(b)(12), inserted 
``(as amended by sections 211, 314, and 474 of this Act)'' in directory 
language of section 163(b)(1) of Pub. L. 98-369, which resulted in no 
change in text but removed an ambiguity which had resulted from failure 
of directory language as originally enacted to indicate that amendments 
of this section by sections 211, 314, and 474 of Pub. L. 98-369 were to 
be executed before the amendment by section 163(b)(1) of Pub. L. 98-369. 
See 1984 Amendment notes below.
    Subsec. (k). Pub. L. 99-514, Sec. 1847(b)(14), substituted ``or a 
credit carryback (as defined in section 6511(d)(4)(C))'' for ``an 
investment credit carryback, or a work incentive program carryback, or a 
new employee credit carryback''.
    Subsecs. (n), (o). Pub. L. 99-514, Sec. 1847(b)(13), added subsec. 
(n) and redesignated former subsec. (n) as (o).
    1984--Subsec. (c)(6). Pub. L. 98-369, Sec. 211(b)(24)(A), 
redesignated par. (7) as (6) and struck out former par. (6) which 
provided that, in the case of any tax imposed under section 802(a) by 
reason of section 802(b)(3) on account of a termination of the taxpayer 
as an insurance company or as a life insurance company to which section 
815(d)(2)(A) applied, or on account of a distribution by the taxpayer to 
which section 815(d)(2)(B) applied such tax could be assessed within 3 
years after the return was filed (whether or not such return was filed 
on or after the date prescribed) for the taxable year for which the 
taxpayer ceased to be an insurance company, the second taxable year for 
which the taxpayer was not a life insurance company, or the taxable year 
in which the distribution was actually made, as the case might be.
    Subsec. (c)(7). Pub. L. 98-369, Sec. 447(a), added par. (7).
    Pub. L. 98-369, Sec. 211(b)(24)(A), redesignated former par. (7) as 
(6).
    Subsec. (c)(8). Pub. L. 98-369, Sec. 131(d)(2), added par. (8).
    Subsec. (g)(3). Pub. L. 98-369, Sec. 801(d)(14), substituted 
``section 6011(c)(2)'' for ``section 6011(e)(2)''.
    Subsec. (k). Pub. L. 98-369, Sec. 163(b)(1), as amended by Pub. L. 
99-514, Sec. 1847(b)(12), redesignated subsec. (m) as (k).
    Pub. L. 98-369, Sec. 211(b)(24)(B), struck out former subsec. (k) 
which provided that in the case of a deficiency attributable to the 
application to the taxpayer of section 815(d)(5) (relating to reductions 
of policyholders surplus account of life insurance companies for certain 
unused deductions), such deficiency could be assessed at any time before 
the expiration of the period within which a deficiency for the last 
taxable year to which the loss described in section 815(d)(5)(A) was 
carried under section 812(b)(2) could be assessed.
    Subsec. (l). Pub. L. 98-369, Sec. 163(b)(1), as amended by Pub. L. 
99-514, Sec. 1847(b)(12), redesignated subsec. (n) as (l) and struck out 
former subsec. (l) which read ``For period of limitations for assessment 
and collection in the case of a joint income return filed after separate 
returns have been filed, see section 6013(b)(3) and (4).''
    Subsec. (l)(3). Pub. L. 98-369, Sec. 314(a)(3), substituted 
``section 4942(g)(2)(B)(ii)'' for ``section 4942(g)(2)(B)(i)(II)'' in 
subsec. (n)(3), which was redesignated subsec. (l)(3) by Pub. L. 98-369, 
Sec. 163(b)(1).
    Subsec. (m). Pub. L. 98-369, Sec. 163(b)(1), as amended by Pub. L. 
99-514, Sec. 1847(b)(12), redesignated subsec. (p) as (m). Former 
subsec. (m) redesignated (k).
    Subsec. (n). Pub. L. 98-369, Sec. 163(b)(1), as amended by Pub. L. 
99-514, Sec. 1847(b)(12), added subsec. (n). Former subsec. (n) 
redesignated (l).
    Subsec. (n)(3). Pub. L. 98-369, Sec. 314(a)(3), substituted 
``section 4942(g)(2)(B)(ii)'' for ``section 4942(g)(2)(B)(i)(II)'' in 
subsec. (n)(3), which was redesignated subsec. (l)(3) by Pub. L. 98-369, 
Sec. 163(b)(1).
    Subsec. (o). Pub. L. 98-369, Sec. 163(b)(1), as amended by Pub. L. 
99-514, Sec. 1847(b)(12), struck out subsec. (o) which read ``For 
extension of period in the case of partnership items (as defined in 
section 6231(a)(3), see section 6229.''
    Subsec. (p). Pub. L. 98-369, Sec. 163(b)(1), as amended by Pub. L. 
99-514, Sec. 1847(b)(12), redesignated subsec. (p) as (m).
    Pub. L. 98-369, Sec. 474(r)(39), redesignated subsec. (q) as (p). 
Former subsec. (p), which related to deficiencies attributable to an 
election under section 44B, was struck out.
    Subsec. (q). Pub. L. 98-369, Sec. 474(r)(39), redesignated subsec. 
(q) as (p).
    Subsec. (q)(3). Pub. L. 98-369, Sec. 714(p)(2)(F), amended par. (3) 
generally. Prior to amendment par. (3) related to partnership items of 
federally registered partnerships and provided that under regulations 
prescribed by the Secretary, rules similar to the rules of subsection 
(o) shall apply to the tax imposed by section 4986.
    1982--Subsec. (o). Pub. L. 97-248 substituted ``Special rules for 
partnership items'' for ``Special rules for partnership items of 
federally registered partnerships'' in heading and, in text, substituted 
cross reference to section 6229 for extension of period in case of 
partnership items (as defined in section 6231(a)(3)), for provisions 
that (1) in the case of any tax imposed by subtitle A with respect to 
any person, the period for assessing a deficiency attributable to any 
partnership item of a federally registered partnership would not expire 
before the later of (A) the date which was 4 years after the date on 
which the partnership return of the federally registered partnership for 
the partnership taxable year in which the item arose was filed (or, 
later, if the date prescribed for filing the return), or (B) if the name 
or address of such person did not appear on the partnership return, the 
date which was 1 year after the date on which such information was 
furnished to the Secretary in such manner and at such place as he might 
prescribe by regulations, (2) for purposes of this subsec., the term 
``partnership item'' meant (A) any item required to be taken into 
account for the partnership taxable year under any provision of 
subchapter K of chapter 1 to the extent that regulations prescribed by 
the Secretary provided that for purposes of this subtitle such item was 
more appropriately determined at the partnership level than at the 
partner level, and (B) any other item to the extent affected by an item 
described in subpar. (A), (3) the extensions referred to in subsec. 
(c)(4), insofar as they related to partnership items, could, with 
respect to any person, be consented to (A) except to the extent the 
Secretary was otherwise notified by the partnership, by a general 
partner of the partnership, or (B) by any person authorized to do so by 
the partnership in writing, and (4) for purposes of this subsec., the 
term ``federally registered partnership'' meant, with respect to any 
partnership taxable year, any partnership (A) interests in which had 
been offered for sale at any time during such taxable year or a prior 
taxable year in any offering required to be registered with the 
Securities and Exchange Commission, or (B) which, at any time during 
such taxable year or a prior taxable year, had been subject to the 
annual reporting requirements of the Securities and Exchange Commission 
which related to the protection of investors in the partnership.
    1980--Subsec. (o). Pub. L. 96-222, Sec. 102(a)(2)(A), redesignated 
subsec. (q), as added by section 212(a) of Pub. L. 95-600, relating to 
special rules for partnership items of Federally registered 
partnerships, as (o). Former subsec. (o), relating to work incentive 
program credit carrybacks, was repealed by Pub. L. 95-628.
    Subsec. (p). Pub. L. 96-222, Sec. 103(a)(6)(G)(X), redesignated 
subsec. (q), as added by section 321(b)(2) of Pub. L. 95-600, relating 
to deficiency attributable to election under section 44B, as (p). Former 
subsec. (p), relating to new employee credit carrybacks, was repealed by 
Pub. L. 95-628.
    Subsec. (q). Pub. L. 96-223 added subsec. (q). Former subsec. (q), 
as added by section 212(a) of Pub. L. 95-600, redesignated (o). Former 
subsec. (q), as added by section 321(b)(2) of Pub. L. 95-600, 
redesignated (p).
    1978--Subsec. (e)(3). Pub. L. 95-600, Sec. 701(t)(3)(A), substituted 
``43, or 44'' for ``or 43'', which required no change in text in view of 
the identical amendment by section 4(d)(4) of Pub. L. 95-227.
    Pub. L. 95-227, Sec. 4(d)(4), substituted ``43, or 44'' for ``or 
43''.
    Subsec. (h). Pub. L. 95-600, Sec. 703(n), (p)(2), substituted 
``section 6213(b)(3)'' for ``section 6213(b)(2)'' and struck out 
provisions relating to the assessment of a deficiency attributable to 
the application of a net operating loss carryback.
    Subsec. (j). Pub. L. 95-628, Sec. 8(c)(1)(A), substituted in heading 
``Certain credit carrybacks'' for ``Investment credit carrybacks'', 
designated existing provision as par. (1), and in par. (1) as so 
designated, inserted heading ``In general'' and in text, substituted 
``credit carryback'' for ``investment credit carryback'' in two places 
and ``unused credit'' for ``unused investment credit'', inserted 
reference to other credit carryback, and substituted reference to 
section 6213(b)(3) for 6213(b)(2), and added par. (2).
    Pub. L. 95-600, Sec. 703(n), substituted ``section 6213(b)(3)'' for 
``section 6213(b)(2)''.
    Subsec. (m). Pub. L. 95-628, Sec. 8(c)(1)(B), struck out references 
to subsecs. (o) and (p) in two places.
    Pub. L. 95-600, Sec. 504(b)(3), inserted ``and refund'' after 
``tentative carryback''.
    Subsec. (n). Pub. L. 95-227, Sec. 4(d)(5), in heading inserted ``and 
similar'' after ``42'', and in par. (1) inserted reference to section 
4975 and inserted ``, plan, or trust (as the case may be)'' after 
``foundation''.
    Subsec. (o). Pub. L. 95-628, Sec. 8(c)(1)(C), struck out subsec. (o) 
which related to work incentive program credit carrybacks.
    Pub. L. 95-600, Sec. 703(n), substituted ``section 6213(b)(3)'' for 
``section 6213(b)(2)''.
    Subsec. (p). Pub. L. 95-628, Sec. 8(c)(1)(C), struck out subsec. (p) 
which related to new employee credit carrybacks.
    Subsec. (q). Pub. L. 95-600, Sec. 212(a), added subsec. (q) relating 
to special rules for partnership items of Federally registered 
partnerships.
    Pub. L. 95-600, Sec. 321(b)(2), added subsec. (q) relating to 
deficiency attributable to election under section 44B.
    1977--Subsec. (m). Pub. L. 95-30, Sec. 202(d)(5)(B), inserted 
references to new employee credit carrybacks and to subsec. (p).
    Subsec. (p). Pub. L. 95-30, Sec. 202(d)(4)(A), added subsec. (p).
    1976--Subsecs. (b)(3), (c)(4), (d), (e)(1)(A)(ii), (2). Pub. L. 94-
455, Sec. 1906(b)(13)(A), struck out ``or his delegate'' after 
``Secretary'' wherever appearing.
    Subsec. (e)(3). Pub. L. 94-455, Sec. 1307(d)(2)(F)(vi), substituted 
``chapter 41, 42, or 43'' for ``chapter 42 or 43''.
    Subsec. (i). Pub. L. 94-455, Secs. 1031(b)(5), 1035(d)(3), 
substituted ``section 904(c)'' for Section 904(d)'' wherever appearing 
and inserted ``or under section 907(f) (relating to carryback and 
carryover of disallowed oil and gas extraction taxes)'' after ``excess 
foreign taxes)'' and ``or 907(f)'' before ``which results in such 
carryback''.
    Subsec. (n)(3). Pub. L. 94-455, Sec. 1302(b), added par. (3).
    Subsec. (o). Pub. L. 94-455, Sec. 2107(g)(2)(A), inserted ``, an 
investment credit carryback,'' after ``net operating loss carryback''.
    1974--Subsec. (e)(3). Pub. L. 93-406 inserted reference to chapter 
43.
    1971--Subsec. (g)(3). Pub. L. 92-178, Sec. 504(c), added par. (3).
    Subsec. (m). Pub. L. 92-178, Sec. 601(e)(2), substituted ``an 
investment credit carryback, or a work incentive program carryback'' for 
``or an investment credit carryback'' and inserted reference to subsec. 
(o) in two places, respectively.
    Subsec. (o). Pub. L. 92-178, Sec. 601(d)(1), added subsec. (o).
    1970--Subsec. (e)(2). Pub. L. 91-614 substituted ``during the period 
for which the return was filed'' for ``during the year''.
    1969--Subsec. (c)(7). Pub. L. 91-172, Sec. 101(g)(2), added par. 
(7).
    Subsec. (e)(3). Pub. L. 91-172, Sec. 101(g)(3), inserted provision 
excluding, in specified cases, chapter 42 taxes from these considered in 
determining the amount of taxes omitted from a return.
    Subsec. (h). Pub. L. 91-172, Sec. 512(e)(1)(A)-(D), substituted 
``loss or capital loss carrybacks'' for ``loss carrybacks'' in heading, 
``loss carryback or a capital loss carryback'' for ``loss carryback,'' 
``operating loss or net capital loss which'' for ``operating loss 
which,'' ``assessed. In the case of a deficiency attributable to the 
application of a net operating loss carryback, such deficiency may be 
assessed'' for ``assessed, or'' and ``if later than the date prescribed 
by the preceding sentence'' for ``whichever is later''.
    Subsec. (j). Pub. L. 91-172, Sec. 512(e)(1)(E), substituted ``loss 
carryback or a capital loss carryback'' for ``loss carryback''.
    Subsec. (m). Pub. L. 91-172, Sec. 512(e)(1)(F), substituted ``net 
operating loss carryback, a capital loss carryback, or an investment 
credit carryback'' for ``net operating loss carryback or an investment 
credit carryback''.
    Subsec. (n). Pub. L. 91-172, Sec. 101(g)(1), added subsec. (n).
    1967--Subsec. (j). Pub. L. 90-225 inserted ``, or, with respect to 
any portion of an investment credit carryback from a taxable year 
attributable to a net operating loss carryback from a subsequent taxable 
year, at any time before the expiration of the period within which a 
deficiency for such subsequent taxable year may be assessed'' after 
``the unused investment credit which results in such carryback may be 
assessed.''
    1966--Subsec. (b). Pub. L. 89-809 inserted reference to chapter 3 in 
pars. (1) and (2) and ``and tax imposed by chapter 3'' in heading of 
par. (2).
    Subsec. (j). Pub. L. 89-721, Sec. 2(f), substituted ``investment 
credit carryback (including deficiencies which may be assessed pursuant 
to the provisions of section 6213(b)(2))'' for ``investment credit 
carryback''.
    Subsec. (m). Pub. L. 89-721, Sec. 3(a), added subsec. (m).
    1965--Subsec. (b)(4). Pub. L. 89-44, Sec. 810(a), added par. (4).
    Subsec. (e). Pub. L. 89-44, Sec. 810(b)(2), substituted 
``Substantial omission of items'' for ``Omission from gross income'' in 
heading.
    Subsec. (e)(3). Pub. L. 89-44, Sec. 810(b)(1), added par. (3).
    1964--Subsec. (f). Pub. L. 88-272 substituted ``gross income and 
adjusted ordinary gross income, described in section 543'' for ``gross 
income, described in section 543(a)''.
    Subsecs. (k), (l). Pub. L. 88-571 added subsec. (k) and redesignated 
former subsec. (k) as (l).
    1962--Subsec. (c)(6). Pub. L. 87-858 substituted ``802(a)'' for 
``802(a)(1)''.
    Subsec. (h). Pub. L. 87-794 authorized assessment of a deficiency 
within 18 months after the date on which the taxpayer files in 
accordance with section 172(b)(3) a copy of the certification issued 
under section 317 of the Trade Expansion Act of 1962, whichever is 
later.
    Subsecs. (j), (k). Pub. L. 87-834 added subsec. (j) and redesignated 
former subsec. (j) as (k).
    1960--Subsecs. (i), (j). Pub. L. 86-780 added subsec. (i) and 
redesignated former subsec. (i) as (j).
    1959--Subsec. (c)(6). Pub. L. 86-69 added par. (6).
    1958--Subsec. (a). Pub. L. 85-859 substituted ``at any time after 
such tax became due and before the expiration of 3 years after the date 
on which any part of such tax was paid'' for ``within 3 years after such 
tax became due''.
    Subsec. (d). Pub. L. 85-866, Sec. 80(a), (b), substituted in first 
sentence ``subsection (c), (e), or (f)'' for ``subsection (c)'', 
designated existing clauses (1) to (3) of second sentence as clause (1) 
and added clauses (2) and (3).
    Subsec. (g)(2). Pub. L. 85-866, Sec. 81(a), substituted 
``organization'' for ``corporation'' wherever appearing.
    Subsecs. (h), (i). Pub. L. 85-866, Sec. 81(b), added subsec. (h) and 
redesignated former subsec. (h) as (i).


                    Effective Date of 1998 Amendment

    Pub. L. 105-206, title III, Sec. 3461(c), July 22, 1998, 112 Stat. 
764, provided that:
    ``(1) In general.--The amendments made by this section [amending 
this section and section 6502 of this title] shall apply to requests to 
extend the period of limitations made after December 31, 1999.
    ``(2) Prior request.--If, in any request to extend the period of 
limitations made on or before December 31, 1999, a taxpayer agreed to 
extend such period beyond the 10-year period referred to in section 
6502(a) of the Internal Revenue Code of 1986, such extension shall 
expire on the latest of--
        ``(A) the last day of such 10-year period;
        ``(B) December 31, 2002; or
        ``(C) in the case of an extension in connection with an 
    installment agreement, the 90th day after the end of the period of 
    such extension.''
    Amendment by section 6023(27) of Pub. L. 105-206 effective July 22, 
1998, see section 6023(32) of Pub. L. 105-206, set out as a note under 
section 34 of this title.
    Amendment by section 6007(e)(2)(A) of Pub. L. 105-206 effective, 
except as otherwise provided, as if included in the provisions of the 
Taxpayer Relief Act of 1997, Pub. L. 105-34, to which such amendment 
relates, see section 6024 of Pub. L. 105-206, set out as a note under 
section 1 of this title.


                    Effective Date of 1997 Amendment

    Section 506(e)(2) of Pub. L. 105-34 provided that: ``The amendment 
made by subsection (b) [amending this section] shall apply to gifts made 
in calendar years ending after the date of the enactment of this Act 
[Aug. 5, 1997].''
    Section 1145(b) of Pub. L. 105-34 provided that: ``The amendment 
made by subsection (a) [amending this section] shall apply to 
information the due date for the reporting of which is after the date of 
the enactment of this Act [Aug. 5, 1997].''
    Amendment by section 1239(e)(2) of Pub. L. 105-34 applicable to 
partnership taxable years ending after Aug. 5, 1997, see section 1239(f) 
of Pub. L. 105-34, set out as a note under section 6225 of this title.
    Section 1284(b) of Pub. L. 105-34 provided that: ``The amendment 
made by this section [amending this section] shall apply to taxable 
years beginning after the date of the enactment of this Act [Aug. 5, 
1997].''
    Amendment by section 1601(g)(2) of Pub. L. 105-34 effective as if 
included in the provisions of the Small Business Job Protection Act of 
1996, Pub. L. 104-188, to which it relates, see section 1601(j) of Pub. 
L. 105-34, set out as a note under section 23 of this title.


                    Effective Date of 1996 Amendment

    Amendment by section 1702(e)(3) of Pub. L. 104-188 effective, except 
as otherwise expressly provided, as if included in the provision of the 
Revenue Reconciliation Act of 1990, Pub. L. 101-508, title XI, to which 
such amendment relates, see section 1702(i) of Pub. L. 104-188, set out 
as a note under section 38 of this title.
    Amendment by section 1703(n)(8) of Pub. L. 104-188 effective as if 
included in the provision of the Revenue Reconciliation Act of 1993, 
Pub. L. 103-66, Secs. 13001-13444, to which such amendment relates, see 
section 1703(o) of Pub. L. 104-188, set out as a note under section 39 
of this title.


                    Effective Date of 1990 Amendment

    Section 11602(e)(2) of Pub. L. 101-508 provided that: ``The 
amendment made by subsection (b) [amending this section] shall apply to 
gifts after October 8, 1990.''


                    Effective Date of 1989 Amendment

    Amendment by Pub. L. 101-239 effective, except as otherwise 
provided, as if included in the provision of the Technical and 
Miscellaneous Revenue Act of 1988, Pub. L. 100-647, to which such 
amendment relates, see section 7817 of Pub. L. 101-239, set out as a 
note under section 1 of this title.


               Effective Date of 1988 AmendmentsAmendments

    Amendment by section 1008(j)(1) of Pub. L. 100-647 effective, except 
as otherwise provided, as if included in the provision of the Tax Reform 
Act of 1986, Pub. L. 99-514, to which such amendment relates, see 
section 1019(a) of Pub. L. 100-647, set out as a note under section 1 of 
this title.
    Amendment by section 4008(c)(2) of Pub. L. 100-647 applicable to 
taxable years beginning after Dec. 31, 1988, see section 4008(d) of Pub. 
L. 100-647, set out as a note under section 41 of this title.
    Amendment by Pub. L. 100-418 applicable to crude oil removed from 
premises on or after Aug. 23, 1988, see section 1941(c) of Pub. L. 100-
418, set out as a note under section 164 of this title.


                    Effective Date of 1987 Amendment

    Amendment by section 10712(c)(2) of Pub. L. 100-203 applicable to 
taxable years beginning after Dec. 22, 1987, see section 10712(d) of 
Pub. L. 100-203, set out as an Effective Date note under section 4955 of 
this title.
    Amendment by section 10714(c) of Pub. L. 100-203 applicable to 
taxable years beginning after Dec. 22, 1987, see section 10714(e) of 
Pub. L. 100-203, set out as an Effective Date note under section 4912 of 
this title.


                    Effective Date of 1986 Amendment

    Amendment by Pub. L. 99-514 effective, except as otherwise provided, 
as if included in the provisions of the Tax Reform Act of 1984, Pub. L. 
98-369, div. A, to which such amendment relates, see section 1881 of 
Pub. L. 99-514, set out as a note under section 48 of this title.


                    Effective Date of 1984 Amendment

    Amendment by section 131(d)(2) of Pub. L. 98-369 applicable to 
transfers or exchanges after Dec. 31, 1984, in taxable years ending 
after such date, with special rules for certain transfers and ruling 
requests before Mar. 1, 1984, see section 131(g) of Pub. L. 98-369, set 
out as a note under section 367 of this title.
    Amendment by section 163(b)(1) of Pub. L. 98-369 applicable to 
expenditures with respect to which the second taxable year described in 
section 118(b)(2)(B) of this title ends after Dec. 31, 1984, see section 
163(c) of Pub. L. 98-369, set out as a note under section 118 of this 
title.
    Amendment by section 211(b)(24) of Pub. L. 98-369 applicable to 
taxable years beginning after Dec. 31, 1983, see section 215 of Pub. L. 
98-369, set out as an Effective Date note under section 801 of this 
title.
    Amendment by section 314(a)(3) of Pub. L. 98-369 effective July 18, 
1984, see section 314(a)(4) of Pub. L. 98-369, set out as a note under 
section 4942 of this title.
    Section 447(b) of Pub. L. 98-369 provided that: ``The amendment made 
by subsection (a) [amending this section] shall apply with respect to 
documents received by the Secretary of the Treasury (or his delegate) 
after the date of the enactment of this Act [July 18, 1984].''
    Amendment by section 474(r)(39) of Pub. L. 98-369 applicable to 
taxable years beginning after Dec. 31, 1983, and to carrybacks from such 
years, see section 475(a) of Pub. L. 98-369, set out as a note under 
section 21 of this title.
    Amendment by section 714(p)(2)(F) of Pub. L. 98-369 effective as if 
included in the provision of the Tax Equity and Fiscal Responsibility 
Act of 1982, Pub. L. 97-248, to which such amendment relates, see 
section 715 of Pub. L. 98-369, set out as a note under section 31 of 
this title.
    Amendment by section 801(d)(14) of Pub. L. 98-369 applicable to 
transactions after Dec. 31, 1984, in taxable years ending after such 
date, see section 805(a)(1) of Pub. L. 98-369, as amended, set out as a 
note under section 245 of this title.


                    Effective Date of 1982 Amendment

    Amendment by Pub. L. 97-248 applicable to partnership taxable years 
beginning after Sept. 3, 1982, with provision for applicability of 
amendment to any partnership taxable year ending after Sept. 3, 1982, if 
partnership, each partner, and each indirect partner requests such 
application and the Secretary of the Treasury or his delegate consents 
to such application, see section 407(a)(1), (3) of Pub. L. 97-248, set 
out as an Effective Date note under section 6221 of this title.


                    Effective Date of 1980 Amendments

    Amendment by Pub. L. 96-223 applicable to periods after Feb. 29, 
1980, see section 101(i) of Pub. L. 96-223, set out as a note under 
section 6161 of this title.
    Amendment by Pub. L. 96-222 effective, except as otherwise provided, 
as if it had been included in the provisions of the Revenue Act of 1978, 
Pub. L. 95-600, to which such amendment relates, see section 201 of Pub. 
L. 96-222, set out as a note under section 32 of this title.


                    Effective Date of 1978 Amendments

    Amendment by Pub. L. 95-628 applicable to carrybacks arising in 
taxable years beginning after Nov. 10, 1978, see section 8(d) of Pub. L. 
95-628, set out as a note under section 6511 of this title.
    Section 212(c) of Pub. L. 95-600 provided that: ``The amendments 
made by this section [amending this section and sections 6511 and 6512 
of this title] shall apply to partnership items arising in partnership 
taxable years beginning after December 31, 1978.''
    Section 321(d)(5) of Pub. L. 95-600, as added by Pub. L. 96-222, 
title I, Sec. 103(a)(6)(B), Apr. 1, 1980, 94 Stat. 209, provided that: 
``The amendments made by subsection (b) [amending this section and 
section 44B of this title] shall apply to taxable years beginning after 
December 31, 1976.''
    Amendment by section 504(b)(3) of Pub. L. 95-600 applicable to 
tentative refund claims filed on and after Nov. 6, 1978, see section 
504(c) of Pub. L. 95-600, set out as a note under section 6411 of this 
title.
    Amendment by section 701(t)(3)(A) of Pub. L. 95-600 effective Oct. 
4, 1976, see section 701(t)(5) of Pub. L. 95-600, set out as a note 
under section 859 of this title.
    Amendment by section 703(n) of Pub. L. 95-600 effective Oct. 4, 
1976, see section 703(r) of Pub. L. 95-600, set out as a note under 
section 46 of this title.
    Amendment by section 703(p)(2) of Pub. L. 95-600 applicable with 
respect to losses sustained in taxable years ending after Nov. 6, 1978, 
see section 703(p)(4) of Pub. L. 95-600, set out as a note under section 
172 of this title.
    Amendment by Pub. L. 95-227 applicable with respect to 
contributions, acts, and expenditures made after Dec. 31, 1977, in and 
for taxable years beginning after such date, see section 4(f) of Pub. L. 
95-227, set out as an Effective Date note under section 192 of this 
title.


                    Effective Date of 1977 Amendment

    Amendment by Pub. L. 95-30 applicable to taxable years beginning 
after Dec. 31, 1976, and to credit carrybacks from such years, see 
section 202(e) of Pub. L. 95-30, set out as an Effective Date note under 
section 51 of this title.


                    Effective Date of 1976 Amendment

    Amendment by section 1031(b)(5) of Pub. L. 94-455 applicable to 
taxable years beginning after Dec. 31, 1975, with specific exceptions, 
see section 1031(c) of Pub. L. 94-455, set out as a note under section 
904 of this title.
    Amendment by section 1035(d)(3) of Pub. L. 94-455 applicable to 
taxes paid or accrued during taxable years ending after Oct. 4, 1976, 
see section 1035(e) of Pub. L. 94-455, set out as a note under section 
907 of this title.
    Amendment by section 1302(b) of Pub. L. 94-455 applicable to taxable 
years beginning after Dec. 31, 1974, see section 1302(c) of Pub. L. 94-
455, set out as a note under section 4942 of this title.
    Amendment by section 1307(d)(2)(F)(vi) of Pub. L. 94-455 applicable 
to taxable years beginning after Dec. 31, 1976, see section 1307(e)(5) 
of Pub. L. 94-455, set out as a note under section 501 of this title.


                    Effective Date of 1974 Amendment

    Amendment by Pub. L. 93-406 applicable, except as otherwise provided 
in section 1017(c) through (i) of Pub. L. 93-406, for plan years 
beginning after Sept. 2, 1974, but, in the case of plans in existence on 
Jan. 1, 1974, amendment by Pub. L. 93-406 applicable for plan years 
beginning after Dec. 31, 1975, see section 1017 of Pub. L. 93-406, set 
out an an Effective Date; Transitional Rules note under section 410 of 
this title.


                    Effective Date of 1971 Amendment

    Amendment by section 504(c) of Pub. L. 92-178 applicable with 
respect to taxable years ending after Dec. 31, 1971, except that a 
corporation may not be a DISC for any taxable year beginning before Jan. 
1, 1972, see section 507 of Pub. L. 92-178, set out as an Effective Date 
note under section 991 of this title.
    Amendment by section 601(d)(1), (e)(2) of Pub. L. 92-178 applicable 
to taxable years beginning after Dec. 31, 1971, see section 601(f) of 
Pub. L. 92-178, set out as a note under section 381 of this title.


                    Effective Date of 1970 Amendment

    Amendment by Pub. L. 91-614 applicable with respect to gifts made 
after Dec. 31, 1970, see section 102(e) of Pub. L. 91-614, set out as a 
note under section 2501 of this title.


                    Effective Date of 1969 Amendment

    Amendment by section 101(g)(1)-(3) of Pub. L. 91-172 effective Jan. 
1, 1970, see section 101(k)(1) of Pub. L. 91-172, set out as an 
Effective Date note under section 4940 of this title.
    Amendment by section 512(e)(1) of Pub. L. 91-172 applicable with 
respect to net capital losses sustained in taxable years beginning after 
Dec. 31, 1969, see section 512(g) of Pub. L. 91-172, set out as a note 
under section 1212 of this title.


                    Effective Date of 1967 Amendment

    Amendment by Pub. L. 90-225 applicable with respect to investment 
credit carrybacks attributable to net operating loss carrybacks from 
taxable years ending after July 31, 1967, see section 2(g) of Pub. L. 
90-225, set out as a note under section 46 of this title.


                    Effective Date of 1966 Amendments

    Section 105(f)(4) of Pub. L. 89-809 provided that: ``The amendments 
made by this subsection [amending this section and section 6513 of this 
title] shall take effect on the date of the enactment of this Act [Nov. 
13, 1966].''
    Amendment by section 2(f) of Pub. L. 89-721 applicable with respect 
to taxable years ending after Dec. 31, 1961, but only in the case of 
applications filed after Nov. 2, 1966, see section 2(g) of Pub. L. 89-
721, set out as a note under section 6411 of this title.
    Section 3(b) of Pub. L. 89-721 provided that: ``The amendment made 
by subsection (a) [amending this section] shall apply in any case where 
the application under section 6411 of the Internal Revenue Code of 1954 
is filed after the date of the enactment of this Act [Nov. 2, 1966].''


                    Effective Date of 1965 Amendment

    Section 810(c) of Pub. L. 89-44 provided that: ``The amendments made 
by subsections (a) and (b) [amending this section] shall apply with 
respect to returns filed on or after July 1, 1965.''


                    Effective Date of 1964 Amendments

    Section 3(f) of Pub. L. 88-571, as amended by Pub. L. 99-514, 
Sec. 2, Oct. 22, 1986, 100 Stat. 2095, provided that: ``The amendments 
made by this section [amending this section and sections 815, 6511, 
6601, and 6611 of this title] shall apply with respect to amounts added 
to policyholders surplus accounts (within the meaning of section 815(c) 
of the Internal Revenue Code of 1986 [formerly I.R.C. 1954]) for taxable 
years beginning after December 31, 1958.''
    Amendment by Pub. L. 88-272 applicable to taxable years beginning 
after Dec. 31, 1963, see section 225(l) of Pub. L. 88-272, set out as a 
note under section 316 of this title.


                    Effective Date of 1962 Amendments

    Section 3(f) of Pub. L. 87-858 provided that the amendment made by 
that section is applicable with respect to taxable years beginning after 
Dec. 31, 1961.
    Amendment by Pub. L. 87-834 applicable with respect to taxable years 
ending after Dec. 31, 1961, see section 2(h) of Pub. L. 87-834, set out 
as an Effective Date note under section 46 of this title.


                    Effective Date of 1960 Amendment

    Amendment by Pub. L. 86-780 applicable to taxable years beginning 
after Dec. 31, 1957, see section 4 of Pub. L. 86-780, set out as a note 
under section 904 of this title.


                    Effective Date of 1959 Amendment

    Amendment by Pub. L. 86-69 applicable only with respect to taxable 
years beginning after Dec. 31, 1957, see section 4 of Pub. L. 86-69, set 
out as a note under section 381 of this title.


                    Effective Date of 1958 Amendments

    Amendment by Pub. L. 85-866 effective Aug. 17, 1954, see section 
1(c)(2) of Pub. L. 85-866, set out as a note under section 165 of this 
title.
    Amendment by Pub. L. 85-859 effective on first day of first calendar 
quarter which begins more than 60 days after Sept. 2, 1958, see section 
1(c) of Pub. L. 85-859.


           Plan Amendments Not Required Until January 1, 1989

    For provisions directing that if any amendments made by subtitle A 
or subtitle C of title XI [Secs. 1101-1147 and 1171-1177] or title XVIII 
[Secs. 1800-1899A] of Pub. L. 99-514 require an amendment to any plan, 
such plan amendment shall not be required to be made before the first 
plan year beginning on or after Jan. 1, 1989, see section 1140 of Pub. 
L. 99-514, as amended, set out as a note under section 401 of this 
title.

                  Section Referred to in Other Sections

    This section is referred to in sections 302, 303, 547, 551, 815, 
860, 982, 1033, 2001, 2016, 2053, 2204, 2504, 5006, 5703, 6013, 6038A, 
6229, 6234, 6255, 6503, 6511, 6672, 7609, 7803 of this title.
