California Code, Insurance Code - INS § 12126

(a) Under a policy issued to an employer insuring employees of the employer;

(b) Under a policy issued to a labor union insuring members of the union;

(c) Under a policy issued to the trustees of a fund established by two or more employers in the same industry or by one or more labor unions or by one or more employers and one or more labor unions, which trustees shall be deemed the policyholder insuring employees of the employers or members of the union;

(d) Under a policy issued to any other organization or combination of organizations, incorporated or otherwise, (including professional associations, trade associations, or other organizations) whose members have common concerns or problems, or have joined together as a means for bargaining for a particular position, or have voluntarily formed or become members of an organization designed to perform a service for its members, or any other substantially similar organization, excluding an organization or combination of organizations that is formed or maintained solely for the purposes of obtaining insurance.