Returns for a period of less than twelve months.
Section 42
SEC. 42. Returns for a period of less than twelve months. — (a) Returns for short period resulting from change of accounting period. — If a taxpayer, other than an individual, with the approval of the Collector of Internal Revenue, changes the basis of computing net income from fiscal year to calendar year a separate return shall be made for the period between the close of the last fiscal year for which return was made and the following December 31. If the change is from calendar year to fiscal year, a separate return shall be made for the period between the close of the new fiscal year. (b) Income computed on basis of short period. — Where a separate return is made under subsection (a) on account of a change in the accounting period, and in all other cases where a separate return is required or permitted, by regulations prescribed by the Secretary of Finance, to be made for a fractional part of a year, then the income shall be computed on the basis of the period for which separate return is made.