Ins. Code, § 4013

(a) Each policyholder of a domestic mutual insurer, other than the holder of a reinsurance contract, is a member of the insurer during the policy period, as defined in the policy or the declarations page of the policy, with all rights and obligations of that membership, and the policy shall so specify.

(b) A “tail” or extended reporting policy or endorsement permitting claims to be reported after the expiration or termination of the policy period shall not extend the policy period of a “claims made” policy and all rights and obligations of membership shall cease upon the expiration or termination of the policy period. If an insurer has allowed or does allow, by contract, conduct, or otherwise, the holder of a “tail” or extended reporting policy or endorsement to have privileges, in whole or in part, identical, or similar to some or all of the rights of membership, the holder is nevertheless not deemed a member.

(c) Subdivision (b) and the modifications to subdivision (a) made by the act adding this subdivision, are declaratory of existing law and do not affect any existing contract rights.