As part of its 2021 Innovation Center Strategy Refresh, the Centers for Medicare and Medicaid Services (CMS) set a goal of having 100 percent of traditional Medicare (TM) beneficiaries in an accountable care “relationship” by 2030. At the time, about 13M beneficiaries were connected to an accountable care organization (ACO). Five years later, that figure has only risen to 14.3M, a paltry growth rate leaving about 60 percent of TM’s 34.7M enrollees still outside of ACOs. A new CMS program, dubbed “LEAD,” will replace ACO REACH, the second largest Medicare ACO program, at the end of this year, but tweaks and improvements are do not change the prognosis that CMS is very unlikely to achieve its 100-percent ACO participation goal.
 
Slow participation growth masks a deeper problem for Medicare ACOs. In 2024, the Medicare Shared Savings Program (MSSP), CMS’s largest ACO program with over 10M assigned beneficiaries, generated a total of $4.1B in earned savings. That same year, inclusive of TM and MA, Medicare spent $1.2T, meaning the MSSP saved less than half a percent of Medicare’s total budget. Even if 100 percent of TM beneficiaries were enrolled in the MSSP, that would amount to savings of around one percent at current efficiencies, a rounding error in total Medicare spend. A gap that vast demands a multitude of explanations (e.g. rebasing benchmarks penalizing success, a focus on primary care avoiding the real cost centers, and slow-walking downside risk and mandatory participation), many of which CMS has identified, but the agency has given no indication of recognizing how deeply inadequate this push toward value has been. Another decade at this growth rate will not move the needle, and it should not take another ten years of paltry results under a slightly different model to recognize that.