A settlement between state regulators and Southern California-based hospital company Prime Healthcare Services has ended the last legal challenge to California's ban on balanced billing of patients. The California Department of Managed Health Care filed a lawsuit against Prime Healthcare in mid-2008. It sought a court order prohibiting Prime from billing patients for care received in hospital emergency rooms but not paid in full by health plans. In the settlement, Prime agreed not to balance bill any health plan member; not to assign any current unpaid bills to collection; audit their records for the past six years to determine whether any members paid balance bills, and provide refunds with interest.