The coverage of Medicare beneficiaries by ACOs is on the upswing—as is the use of risk-based reimbursement models. As of January 2026, 14.3 million Medicare beneficiaries, approximately 23%, were enrolled in Accountable Care Organizations (ACOs), up from 13.7 million in 2025, according to a new CMS publication, 2026 Medicare Accountable Care Organization Initiatives Participation Highlights. This includes consumers whose clinicians are in the Medicare Shared Savings Program ACOs or are served by provider organizations participating in the CMS Innovation Center accountable care models and other CMS Innovation Center models.

For the 2026 performance year, CMS approved 134 applications for the Shared Savings Program, including 72 new ACOs and 62 renewing or reentering ACOs (see …