Cal. Gov. Code § 6512.2
If the purpose set forth in the agreement is to pool the self-insurance claims of two or more local public entities, the agreement may provide that termination by any party to the agreement shall not be construed as a completion of the purpose of the agreement and shall not require the repayment or return to the parties of all or any part of any contributions, payments, or advances made by the parties until the agreement is rescinded or terminated as to all parties. If the purpose set forth in the agreement is to pool the self-insurance claims of two or more local public entities, it shall not be considered an agreement for the purposes of Section 895.2, provided that the agency responsible for carrying out the agreement is a member of the pool and the pool purchases insurance or reinsurance to cover the activities of that agency in carrying out the purposes of the agreement. The agreement may provide that after the completion of its purpose, any surplus money remaining in the pool shall be returned in proportion to the contributions made and the claims or losses paid.
Ca. Gov. Code § 6512.2