The Accountable Care Act specified certain ACO participants that are eligible to participate in the Shared Savings Program and granted CMS the authority to include other types of ACO participants. CMS chose to expand the list of eligible ACO participants beyond the statutory mandate to allow for innovation in possible ACO models and to encourage movement away from the current fee-for-service model with the addition of shared savings incentives. CMS chose this open approach despite concerns that the inclusion of other providers would not produce the efficiencies CMS was attempting to incentivize providers to create. (For example, CMS considered that the inclusion of specialists alongside primary care physicians in an ACO might cause inefficiencies such as duplicative or unnecessary lab testing or imaging, but nevertheless included specialists.) Under the ACA and the proposed CMS rule, ACO participants authorized to form an ACO are:

• ACO professionals in group practice arrangements
• Networks of individual practices of ACO professionals
• Partnerships or joint venture arrangements between hospitals and ACO professionals
• Hospitals employing ACO professionals
• Critical Access Hospitals billing under Method II

CMS specifically discussed the ability of Federally Qualified Health Centers (FQHCs) or Rural Health Centers (RHCs) to form their own ACOs and found that there is a lack of reporting of the data elements needed to assign beneficiaries to an FQHC or RHC as an independent ACO. Medicare, however, recognized the value of these entities, especially in rural areas. Consequently, while they may not form their own ACOs, FQHCs and RHCs may be participants along with other Medicare enrolled providers (such as SNFs) and suppliers. In addition, in recognition of their importance in the healthcare system, the proposed rule provides for additional incentives for FQHC and RHC participation in an ACO. CMS is seeking comments on whether other provider types should be eligible to independently participate in the Shared Savings Program.