In group retrospective rating, participating employers become members of an enrolled group sponsored by an approved organization. Employers continue to pay premiums directly to the department as determined by chapter 296-17 WAC. We calculate the group's retrospective rating premiums as though the standard premiums paid by members of the group were paid by the sponsor, and claims assigned to employer members were assigned to the group sponsor. Group sponsors are responsible for the retrospective rating premiums for the coverage period enrolled. If an adjustment results in us refunding premiums, the refund is the property of the group sponsor. If an adjustment results in us assessing additional premiums, the additional premiums are the responsibility of the group sponsor. With limited exceptions explained in these rules, the department is not involved in the private contractual relationship between group sponsor and group member.