Section 417.580 - Basis and scope(a)Basis. This subpart implements those portions of section 1876 (a), (e), and (g) of the Act that pertain to the amount CMS pays an organization for its Medicare enrollees who are enrolled on a risk basis.(b)Scope. This subpart sets forth- (2) Procedures for determining the HMO's or CMP's payment rate; and(3) Procedures for determining the additional benefits (and their value) the HMO or CMP must provide to its Medicare enrollees.50 FR 1346, Jan. 10, 1985; 50 FR 20570, May 17, 1985, as amended at 58 FR 38080, July 15, 1993; 60 FR 46231, Sept. 6, 1995