42 CFR § 408.90
Termination of group billing arrangement
June 11, 2020
(a) A group billing arrangement may be terminated either by the group payer or by CMS upon 30 days' notice.
(b) CMS may terminate the arrangement if it finds that the group payer is not acting in the best interest of the enrollees or that, for any other reason, the arrangement has proved inconvenient for CMS.