Reg. § 1.6654-3 Short taxable years of individuals.

(1) In any case in which the taxable year for which an underpayment of estimated tax exists is a short taxable year due to a change in annual accounting periods, in determining the tax:

(2) If the taxable year for which an underpayment of estimated tax exists is a short taxable year due to a change in annual accounting periods, in annualizing the taxable income for the months in the taxable year preceding an installment date, for purposes of section 6654(d)(1)(C), the personal exemptions allowed as deductions under section 151 shall be reduced to the same extent that they are reduced under section 443(c) in computing the tax for a short taxable year.

(3) If “the preceding taxable year” referred to in section 6654(d)(4) was a short taxable year, for purposes of determining the applicability of the exception described in section 6654(d)(4), the tax, computed on the basis in the facts shown on the return for the preceding year, shall be the tax computed on the annual basis in the manner described in section 443(b)(1) (prior to its reduction in the manner described in the last sentence thereof). If the tax rates or the taxpayer's status with respect to personal exemptions for the taxable year with respect to which the underpayment occurs differ from such rates or status applicable to the preceding taxable year, the tax determined in accordance with this subparagraph shall be recomputed to reflect the rates and status applicable to the year with respect to which the underpayment occurs.