CA Rev & Tax Code Section 17565

(a)

The taxable year of a taxpayer may not be different than the taxable year used for purposes of the Internal Revenue Code, unless initiated or approved by the Franchise Tax Board.

(b)

For purposes of this section, whenever a taxpayer is required to make a federal return for a period of less than 12 months, that period shall be deemed to be a taxable year, and Section 17552 shall apply.