CMS Releases Final Mandatory Participant List for New Medicare Specialist Payment Model Starting January 2027

The Centers for Medicare and Medicaid Services announced on September 17, 2026 that the final participant list for the Ambulatory Specialty Model (ASM) is now available, ahead of the model's January 1, 2027 start.

The ASM is a mandatory, five-year Medicare payment model running through December 31, 2031. It applies to specialists in roughly one-quarter of the country's metropolitan areas who have historically treated at least 20 heart failure or low back pain episodes per year under Original Medicare. Heart failure participants are cardiologists. Low back pain participants include anesthesiologists, pain management specialists, neurosurgeons, orthopedic surgeons, and physical medicine and rehabilitation physicians.

Under the model, a participant's future Medicare Part B payments are adjusted based on peer comparisons across quality, cost, improvement activities, and health information data sharing. In the first two performance years, adjustments range from minus 9 percent to plus 9 percent. By the fifth year, the range expands to plus or minus 12 percent.

The model is designed to improve coordination between specialists and primary care providers and to reduce avoidable hospitalizations tied to those two conditions. Medicare patients treated by participating specialists are not charged differently and do not need to take any action. Patients can ask their specialist whether they are participating in the model.

Specialists can verify whether they appear on the mandatory participant list at CMS's data portal for the Ambulatory Specialty Model.