California Code, Insurance Code - INS § 11750

(a) The purpose of this article is to promote the public welfare by regulating concert of action between insurers in collecting and tabulating rating information and other data that may be helpful in the making of adequate pure premium rates for workers' compensation insurance and for employers liability insurance incidental thereto and written in connection therewith for all admitted insurers and in submitting them to the commissioner for approval; to authorize and regulate the existence and cooperation of qualified rating organizations to one of which each workers' compensation insurer shall belong; to authorize and regulate cooperation between insurers, rating organizations and advisory organizations in ratemaking and other related matters to the end that the purposes of this chapter may be complied with and carried into effect.

(b) Notwithstanding any other provision of law, within 60 days of receiving an advisory pure premium rate filing made pursuant to subdivision (b) of Section 11750.3, the Insurance Commissioner shall hold a public hearing, and within 30 days of the conclusion of the hearing, approve, disapprove, or modify the proposed rate.