This brief describes CAH participation in ACOs and the financial performance and organizational characteristics of participating and non-participating CAHs. An understanding of the financial and operational factors that may be important to ACO participation may benefit hospital leaders and State Flex Programs as they identify areas for improvement and benchmark performance. The brief finds that as compared to CAHs not participating in an ACO or not responding, CAHs that were leading or participating in an ACO had greater net patient revenue and were more likely to be in the Midwest region, not-for-profit, and affiliated with a health system. Additionally, CAHs leading or participating in an ACO had higher operating and total margins, fewer days revenue in accounts receivable, greater outpatient revenue as a proportion of total revenue, and a lower Medicare inpatient payer mix.