121 new organizations will be participating in Medicare accountable care organization programs, the Centers for Medicare & Medicaid Services announced this week.

100 new ACOs will join the 150 already participating in the Medicare Shared Savings Program, which rewards organizations that reduce their growth in health care costs while meeting quality performance standards. Of the 250 overall participants, 39 will also participate in a new ACO Investment Model that will provide pre-paid shared savings to encourage the formation of new ACOs in rural and underserved areas.

Another 21 ACOs will participate in the Next Generation ACO Model, a new initiative that features prospectively set benchmarks and enables participating providers to take on greater financial risk, with the opportunity for greater shared rewards as an incentive for doing so. Nearly half of these new ACOs will be led by doctors.

Once these new programs are launched, nearly nine million Medicare beneficiaries will be served through ACOs.

For further information about CMS’s expansion of ACO programs, see this New York Times article and this CMS news release.