California Code, Insurance Code - INS § 10089.24

(a) Notwithstanding any other provision of this chapter, the maximum permissible assessment pursuant to Section 10089.23 of a participating insurer that began renewing business into the authority less than 12 months prior to the date of the assessment shall be based on the residential earthquake market share of business actually placed into the authority by the insurer as of the date of the assessment.

(b) Notwithstanding any other provision of this chapter, the maximum permissible assessments pursuant to Section 10089.23 that are permitted for all participating insurers not covered by subdivision (a) shall not be modified to reflect the addition of a new participating insurer until 12 months after that insurer has begun renewing business into the authority.