Waiver of Restrictions on Assessment

§ 6213. Restrictions applicable to deficiencies; petition to Tax Court(a) Time for filing petition and restriction on assessmentWithin 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. (b) Exceptions to restrictions on assessment(1) Assessments arising out of mathematical or clerical errorsIf 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.