January 2022. Accountable care organizations continue to increase in the population for whom they are responsible for the total costs of care. Incentives to coordinate care for ACO patients may lead to increased data sharing between hospitals and other providers like long-term care, and behavioral health. We used 4 years of hospital survey data to analyze if hospitals expand their data exchange networks after joining ACOs, and found that ACO membership increases information network breadth by 30%. However, hospitals in markets with considerable ACO presence are able to expand networks more and more quickly than hospitals in markets with fewer other ACO participants to partner with.