Cal. Ins. Code § 12101

An insurer may be organized and admitted to transact financial guaranty insurance in the manner prescribed for stock property and casualty insurers by the laws of this state. Except as provided in Section 12118, an insurer shall be required to be licensed to transact financial guaranty insurance in California before it transacts that insurance in this state. An insurer shall become admitted to transact financial guaranty insurance upon making application and complying with all the requirements of the law.