Cal. Rev. & Tax. Code § 25102

In the case of two or more persons, as defined in Section 19 of this code, owned or controlled directly or indirectly by the same interests, the Franchise Tax Board may permit or require the filing of a combined report and such other information as it deems necessary and is authorized to impose the tax due under this part as though the combined entire net income was that of one person, or to distribute, apportion, or allocate the gross income or deductions between or among such persons, if it determines that such consolidation, distribution, apportionment, or allocation is necessary in order to reflect the proper income of any such persons.