General rule. (1) Upon the mailing of a notice of deficiency for income, estate, gift, chapter 41, 42, 43, or 44 tax under the provisions of section 6212, the period of limitation on assessment and collection of any deficiency is suspended for 90 days after the mailing of a notice of such deficiency if the notice of deficiency is addressed to a person within the States of the Union and the District of Columbia, or 150 days if such notice of deficiency is addressed to a person outside the States of the Union and the District of Columbia (not counting Saturday, Sunday, or a legal holiday in the District of Columbia as the 90th or 150th day), plus an additional 60 days thereafter in either case. If a proceeding in respect of the deficiency is placed on the docket of the Tax Court, the period of limitation is suspended until the decision of the Tax Court becomes final, and for an additional 60 days thereafter. If a notice of deficiency is mailed to a taxpayer within the period of limitation and the taxpayer does not appeal therefrom to the Tax Court, the notice of deficiency so given does not suspend the running of the period of limitation with respect to any additional deficiency shown to be due in a subsequent deficiency notice.

This paragraph may be illustrated by the following example:

A taxpayer filed a return for the calendar year 1973 on April 15, 1974; the notice of deficiency was mailed to him (at an address within the United States) on April 15, 1977; and he filed a petition with the Tax Court on July 14, 1977. The decision of the Tax Court became final on November 6, 1978. The running of the period of limitation for assessment is suspended from April 15, 1977, to January 5, 1979, which date is 60 days after the date (November 6, 1978), on which the decision became final. If in this example the taxpayer had failed to file a petition with the Tax Court, the running of the period of limitation for assessment would then be suspended from April 15, 1977 (the date of notice), to September 12, 1977 (that is, for the 90-day period in which he could file a petition with the Tax Court, and for 60 days thereafter).

For provisions relating to suspension of the running of the period of limitation with respect to collection of “second tier” excise taxes (as defined in section 4963) until final resolution of a refund proceeding described in sections 4961 and 7422 for the determination of the taxpayer's liability for the second tier taxes, see § 53.4961-2 (e)(4).

Corporations joining in consolidated return. If a notice under section 6212(a) with respect to a deficiency in tax imposed by subtitle A of the Code for any taxable year is mailed to a corporation, the suspension of the running of the period of limitation provided in section 6503(a)(1) shall apply in the case of corporations with which such corporation made a consolidated income tax return for such taxable year. Under § 1.1502-77(a) of this chapter (Income Tax Regulations), relating to consolidated returns, notices of deficiency are mailed only to the common parent.