Two kinds of outside helpers shape the property market: one writes the rulebook and crunches the numbers, the other grades the players.
Insurance Services Office (ISO): an advisory organization. It develops standard policy forms and loss data that insurers may use. Exam questions are based on standard forms, using current ISO editions where available.
Independent rating organizations: AM Best, Fitch, Moody's and Standard and Poor's. A rating is the agency's opinion of an insurer's financial strength, including its ability to pay claims. It is an opinion, not a guarantee, and says nothing about price.
Loss cost rating: a prospective loss cost is the part of a rate that covers expected losses for a class, without any insurer's expenses or profit. Each insurer adds its own expenses and profit to reach its rate, so companies with different costs can price differently from the same shared data.
California: Section 1855.5 lets an advisory organization prepare policy forms and prospective loss costs for the commissioner's approval, but it may not set rates or issue manuals with final rates.