Within 90 days, or 150 days if the notice is addressed to a person outside the United States, after the notice of deficiency authorized in section 6212 is mailed (not counting Saturday, Sunday, or a legal holiday in the District of Columbia as the last day), the taxpayer may file a petition with the Tax Court for a redetermination of the deficiency. Except as otherwise provided in section 6851, 6852, or 6861 no assessment of a deficiency in respect of any tax imposed by subtitle A, or B, chapter 41, 42, 43, or 44 and no levy or proceeding in court for its collection shall be made, begun, or prosecuted until such notice has been mailed to the taxpayer, nor until the expiration of such 90-day or 150-day period, as the case may be, nor, if a petition has been filed with the Tax Court, until the decision of the Tax Court has become final. Notwithstanding the provisions of section 7421(a), the making of such assessment or the beginning of such proceeding or levy during the time such prohibition is in force may be enjoined by a proceeding in the proper court, including the Tax Court, and a refund may be ordered by such court of any amount collected within the period during which the Secretary is prohibited from collecting by levy or through a proceeding in court under the provisions of this subsection. The Tax Court shall have no jurisdiction to enjoin any action or proceeding or order any refund under this subsection unless a timely petition for a redetermination of the deficiency has been filed and then only in respect of the deficiency that is the subject of such petition. Any petition filed with the Tax Court on or before the last date specified for filing such petition by the Secretary in the notice of deficiency shall be treated as timely filed.
If the taxpayer is notified that, on account of a mathematical or clerical error appearing on the return, an amount of tax in excess of that shown on the return is due, and that an assessment of the tax has been or will be made on the basis of what would have been the correct amount of tax but for the mathematical or clerical error, such notice shall not be considered as a notice of deficiency for the purposes of subsection (a) (prohibiting assessment and collection until notice of the deficiency has been mailed), or of section 6212(c)(1) (restricting further deficiency letters), or of section 6512(a) (prohibiting credits or refunds after petition to the Tax Court), and the taxpayer shall have no right to file a petition with the Tax Court based on such notice, nor shall such assessment or collection be prohibited by the provisions of subsection (a) of this section. Each notice under this paragraph shall set forth the error alleged and an explanation thereof.
Notwithstanding section 6404(b), a taxpayer may file with the Secretary within 60 days after notice is sent under paragraph (1) a request for an abatement of any assessment specified in such notice, and upon receipt of such request, the Secretary shall abate the assessment. Any reassessment of the tax with respect to which an abatement is made under this subparagraph shall be subject to the deficiency procedures prescribed by this subchapter.
If the Secretary determines that the amount applied, credited, or refunded under section 6411 is in excess of the overassessment attributable to the carryback or the amount described in section 1341(b)(1) with respect to which such amount was applied, credited, or refunded, he may assess without regard to the provisions of paragraph (2) the amount of the excess as a deficiency as if it were due to a mathematical or clerical error appearing on the return.
Any amount paid as a tax or in respect of a tax may be assessed upon the receipt of such payment notwithstanding the provisions of subsection (a). In any case where such amount is paid after the mailing of a notice of deficiency under section 6212, such payment shall not deprive the Tax Court of jurisdiction over such deficiency determined under section 6211 without regard to such assessment.
If the taxpayer does not file a petition with the Tax Court within the time prescribed in subsection (a), the deficiency, notice of which has been mailed to the taxpayer, shall be assessed, and shall be paid upon notice and demand from the Secretary.
The taxpayer shall at any time (whether or not a notice of deficiency has been issued) have the right, by a signed notice in writing filed with the Secretary, to waive the restrictions provided in subsection (a) on the assessment and collection of the whole or any part of the deficiency.
The running of the time prescribed by subsection (a) for filing a petition in the Tax Court with respect to the taxes imposed by section 4941 (relating to taxes on self-dealing), 4942 (relating to taxes on failure to distribute income), 4943 (relating to taxes on excess business holdings), 4944 (relating to investments which jeopardize charitable purpose), 4945 (relating to taxes on taxable expenditures), 4951 (relating to taxes on self-dealing), or 4952 (relating to taxes on taxable expenditures), 4955 (relating to taxes on political expenditures), 4958 (relating to private excess benefit), 4971 (relating to excise taxes on failure to meet minimum funding standard), 4975 (relating to excise taxes on prohibited transactions) shall be suspended for any period during which the Secretary has extended the time allowed for making correction under section 4963(e).
In any case under title 11 of the United States Code, the running of the time prescribed by subsection (a) for filing a petition in the Tax Court with respect to any deficiency shall be suspended for the period during which the debtor is prohibited by reason of such case from filing a petition in the Tax Court with respect to such deficiency, and for 60 days thereafter.
For purposes of the second and third sentences of subsection (a), the filing of a proof of claim or request for payment (or the taking of any other action) in a case under title 11 of the United States Code shall not be treated as action prohibited by such second sentence.