2026 Medicare ACO Initiatives: New Models, Increased Participation, and Enhanced Patient Care

On February 4, the Centers for Medicare & Medicaid Services (CMS) released a fact sheet about the 2026 Medicare Accountable Care Organization (ACO) participation. As of January 2026, an estimated 14.3 million Medicare beneficiaries will receive care coordinated by ACOs, up from 13.7 million in 2025, marking a 4.4 percent increase, CMS reported. This includes patients whose healthcare providers participate in Medicare Shared Savings Program ACOs, and entities involved in CMS Innovation Center accountable care models, as well as other CMS Innovation Center models focused on total cost of care, advanced primary care, and specialty care.

ACOs achieve savings because healthcare providers are held accountable for reducing costs and improving quality of care, delivering a win for both patients and the Medicare Trust Funds, CMS explained. “In Performance Year 2024, the most recently reconciled performance year, Shared Savings Program ACOs earned shared savings totaling $4.1 billion and saved Medicare $2.5 billion.”

CMS stated that the current administration continues to grow ACO participation through changes to the Shared Savings Program and CMS Innovation Center models: 

• In 2026, 82.8 percent of Shared Savings Program ACOs are in Level E of the BASIC track or the ENHANCED track, both of which meet the criteria to be an Advanced Alternative Payment Model (Advanced APM) under the Quality Payment Program.
• CMS finalized changes in the CY 2026 Physician Fee Schedule Final Rule that are intended to increase the number of Shared Savings Program ACOs participating in two-sided risk, in which organizations are accountable for losses as well as savings.
• The ACO REACH Model updated its financial methodology in 2025 to ensure future cost savings.
• The recently announced Long-term Enhanced ACO Design (LEAD) Model will launch in 2027 at the conclusion of ACO REACH. LEAD builds upon earlier accountable care work while appealing to a broader mix of health care providers, including those with specialized patient populations and those new to ACOs, such as smaller, independent, or rural-based practices.

CMS Accountable Care Organization initiatives — participation highlights:

• For the 2026 performance year, CMS approved 134 applications for the Shared Savings Program, including 72 new ACOs and 62 renewing or reentering ACOs. This brings the total number of ACOs participating in the Shared Savings Program for Performance Year 2026 to 511, up from 476 ACOs participating in 2025. These Shared Savings Program ACOs, with more than 700,000 health care providers and organizations, will serve 12.6 million people with Traditional Medicare, a 12.3 percent increase.
• The ACO REACH Model includes 74 ACOs, 125,909 healthcare providers and organizations, and approximately 1.7 million people with Traditional Medicare. In 2026, this model features 614 Federally Qualified Health Centers, Rural Health Clinics, and Critical Access Hospitals participating.
• The Kidney Care Choices (KCC) Model includes 74 Kidney Contracting Entities (KCEs), which are responsible for the quality of care and the care of their aligned patients under Traditional Medicare.
• The ACO PC Flex Model involves 23 ACOs serving 359,720 people with Traditional Medicare and tests a new primary care payment model within the Shared Savings Program.

Medicare beneficiaries whose physicians participate in accountable care organizations (ACOs), particularly those taking on financial risk for cost and quality, receive substantially more primary and preventive care than beneficiaries outside these models, according to new data released by Accountable for Health, as reported by Pearl Steinzor on February 4 for AJMC. “By shifting from traditional fee-for-service models—which reimburse per visit or procedure—to frameworks that reward quality and outcomes, ACOs can empower clinicians to emphasize prevention, continuity of care, and proactive management of chronic conditions.”