Insurance Code § 11732

Rates shall be adequate to cover an insurer’s losses and expenses. Rates shall not tend to create a monopoly in the market. For the purpose of this section, the rates of any individual insurer, other than the State Compensation Insurance Fund, are presumed to create a monopoly in the market if the insurer has a market share, based on a percentage of statewide workers’ compensation premium, equivalent to 20 percent or more of the premium written by all insurers other than the State Compensation Insurance Fund.