California Code, Financial Code - FIN § 16100

(a) A foreign (other state) credit union that has a license to establish and maintain an office in this state may engage in activities at such office as may be authorized under the laws of its home state and the laws of this state that are applicable to credit unions.

(b) Nothing in subdivision (a) authorizes a foreign (other state) credit union to engage in any activity at a California branch office or California facility that it is not authorized to transact or is prohibited from transacting under the law of its home state or that credit unions organized under the laws of this state are not authorized to transact or are prohibited from transacting.