California Code, Revenue and Taxation Code - RTC § 23224.5

(a) After December 31, 1971, if a corporation which has been subject to the provisions of Chapter 3  1 commences to do business in this state, such corporation shall pay a tax under Chapter 3 for the whole of the taxable year it commences to do such business.

(b) For the purposes of Sections 23151.1 and 23183.1, the first taxable year subsequent to the taxable year the corporation commences to do such business (as described in subdivision (a)) shall be treated as the taxable year of commencement.