Cal. Ins. Code § 12640.07

(a) Mortgage guaranty insurance may be transacted in this state only by a stock or mutual casualty insurer holding a certificate of authority for the transaction of the insurance pursuant to this chapter, and shall be written only to insure either of the following:
1. (1) Loans secured by first liens on authorized real estate securities not exceeding, at the time the loan is made, 103 percent of the fair market value of the authorized real estate security, as defined in subparagraph (A) of paragraph (1) of subdivision (b) of Section 12640.02.
2. (2) Loans secured by junior liens, as defined in subparagraph (B) of paragraph (1) of subdivision (b) of Section 12640.02.
(b) Any reciprocal insurer engaging in this type of business shall be bound by all provisions of this chapter, including the requirements as to paid-in capital and paid-in surplus.