Cal. Rev. & Tax. Code § 25104

In the case of a corporation liable to report under this part owning or controlling, either directly or indirectly, another corporation, or other corporations, and in the case of a corporation liable to report under this part and owned or controlled, either directly or indirectly, by another corporation, the Franchise Tax Board may require a consolidated report showing the combined net income or such other facts as it deems necessary. The Franchise Tax Board is authorized and empowered, in such manner as it may determine, to assess the tax against either of the corporations whose net income is involved in the report upon the basis of the combined entire net income and such other information as it may possess, or it may adjust the tax in such other manner as it shall determine to be equitable if it determines it to be necessary in order to prevent evasion of taxes or to clearly reflect the net income earned by said corporation or corporations from business done in this State.