26 U.S.C. § 1378 — Taxable year of S corporation

1. (a)General ruleFor purposes of this subtitle, the taxable year of an S corporation shall be a permitted year.
2. (b)Permitted year definedFor purposes of this section, the term “permitted year” means a taxable year which—For purposes of paragraph (2), any deferral of income to shareholders shall not be treated as a business purpose.
   1. (1)is a year ending December 31, or
   2. (2)is any other accounting period for which the corporation establishes a business purpose to the satisfaction of the Secretary.