On January 18, 2017, the Centers for Medicare & Medicaid Services (CMS) announced that 562 Medicare accountable care organizations (ACOs) will participate in 2017. There are 480 ACOs participating in the Medicare Shared Savings Program (MSSP), 45 in the Next Generation ACO Model, and 37 in the Comprehensive End-Stage Renal Disease (ESRD) Care model, or CEC. Among these ACOs, 121 are in a risk-bearing track, including in the MSSP, Next Generation ACO Model, and CEC Model. In the same announcement, CMS noted that more than 359,000 clinical professionals are confirmed to participate in four of CMS’s . . .