RCW 48.09.110: Membership.

(1) Each holder of one or more insurance contracts issued by a domestic mutual insurer, other than a contract of reinsurance, is a member of the insurer, with the rights and obligations of such membership, and each insurance contract so issued shall effectively so stipulate.

(2) Any person, government or governmental agency, state or political subdivision thereof, public or private corporation, board, association, estate, trustee or fiduciary, may be a member of a mutual insurer.