The Long‑term Enhanced ACO Design (LEAD) model is the Centers for Medicare and Medicaid Services’ (CMS) next‑generation accountable care model and the formal successor to ACO REACH, beginning January 1, 2027. LEAD is a voluntary, 10‑year model designed to support long‑term participation in total cost‑of‑care accountability while also improving financial sustainability for organizations serving complex and high‑needs Medicare populations. It’s also the longest running ACO model in the history of the Center of Medicare and Medicaid Innovation (CMMI).