Liability insurance companies owned by their policyholders. Membership is limited to people in the same business or activity, which exposes them to similar liability risks. The purpose is to assume and spread liability exposure to group members and to provide an alternative risk financing mechanism for liability. These entities are formed under the Liability Risk Retention Act of 1986. Under law, risk retention groups are precluded from writing certain coverages, most notably property lines and workers’ compensation. They predominately write medical malpractice, general liability, professional liability, products liability and excess liability coverages. They can be formed as a mutual or stock company, or a reciprocal.