Sec. 481 Adjustments required by changes in method of accounting
(a) General rule. In computing the taxpayer's taxable income for any taxable year (referred to in this section as the "year of the change") --
(1) if such computation is under a method of accounting different from the method under which the taxpayer's taxable income for the preceding taxable year was computed, then
(2) there shall be taken into account those adjustments which are determined to be necessary solely by reason of the change in order to prevent amounts from being duplicated or omitted, except there shall not be taken into account any adjustment in respect of any taxable year to which this section does not apply unless the adjustment is attributable to a change in the method of accounting initiated by the taxpayer.
(b) Limitation on tax where adjustments are substantial.
(1) Three year allocation. If --
(A) the method of accounting from which the change is made was used by the taxpayer in computing his taxable income for the 2 taxable years preceding the year of the change, and
(B) the increase in taxable income for the year of the change which results solely by reason of the adjustments required by subsection (a)(2) exceeds $3,000,
then the tax under this chapter attributable to such increase in taxable income shall not be greater than the aggregate increase in the taxes under this chapter (or under the corresponding provisions of prior revenue laws) which would result if one-third of such increase in taxable income were included in taxable income for the year of the change and one-third of such increase were included for each of the 2 preceding taxable years.
(2) Allocation under new method of accounting. If --
(A) the increase in taxable income for the year of the change which results solely by reason of the adjustments required by subsection (a)(2) exceeds $3,000, and
(B) the taxpayer establishes his taxable income (under the new method of accounting) for one or more taxable years consecutively preceding the taxable year of the change for which the taxpayer in computing taxable income used the method of accounting from which the change is made,
then the tax under this chapter attributable to such increase in taxable income shall not be greater than the net increase in the taxes under this chapter (or under the corresponding provisions of prior revenue laws) which would result if the adjustments required by subsection (a)(2) were allocated to the taxable year or years specified in subparagraph (B) to which they are properly allocable under the new method of accounting and the balance of the adjustments required by subsection (a)(2) was allocated to the taxable year of the change.
(3) Special rules for computations under paragraphs (1) and (2). For purposes of this subsection --
(A) There shall be taken into account the increase or decrease in tax for any taxable year preceding the year of the change to which no adjustment is allocated under paragraph (1) or (2) but which is affected by a net operating loss (as defined in section 172) or by a capital loss carryback or carryover (as defined in section 1212), determined with reference to taxable years with respect to which adjustments under paragraph (1) or (2) are allocated.
(B) The increase or decrease in the tax for any taxable year for which an assessment of any deficiency, or a credit or refund of any overpayment, is prevented by any law or rule of law, shall be determined by reference to the tax previously determined (within the meaning of section 1314(a)) for such year.
(c) Adjustments under regulations. In the case of any change described in subsection (a), the taxpayer may, in such manner and subject to such conditions as the Secretary may by regulations prescribe, take the adjustments required by subsection (a)(2) into account in computing the tax imposed by this chapter for the taxable year or years permitted under such regulations.
(d) Adjustments attributable to conversion from S corporation to C corporation.
(1) In general. In the case of an eligible terminated S corporation, any adjustment required by subsection (a)(2) which is attributable to such corporation's revocation described in paragraph (2)(A)(ii) shall be taken into account ratably during the 6-taxable year period beginning with the year of change.
(2) Eligible terminated S corporation. For purposes of this subsection, the term "eligible terminated S corporation" means any C corporation --
(A) which --
(i) was an S corporation on the day before the date of the enactment of the Tax Cuts and Jobs Act, and
(ii) during the 2-year period beginning on the date of such enactment makes a revocation of its election under section 1362(a), and
(B) the owners of the stock of which, determined on the date such revocation is made, are the same owners (and in identical proportions) as on the date of such enactment.
