(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

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