Accountable care organizations are groups of providers who agree to accept the responsibility for elevating the health status of a defined group of patients, with the goal of enabling people to take charge of their health and enroll in shared decision-making with providers. The large initial investment required (estimated at $1.8 million) to develop an ACO implies that the participation of large health care organizations, especially hospitals and health systems, is required for success. Findings of the study suggest that ACOs based in a larger hospital organizations are more likely to meet CMS criteria for formation because of financial and structural assets of those entities.