Healthcare reform favors the powerful. Understanding the emerging levers of power can help pharmaceutical companies and payers navigate the ever-changing ACO landscape. HealthLeaders-InterStudy's ACO PlayBook identifies the top trends, top providers and top markets for accountable care activity in the United States. The PlayBook also presents models for assessing ACO power and footprint, the role of provider integration and market dynamics, and the impact of each of these characteristics. Also presented are the distribution of ACO contracts across reimbursement model and payer type, and proprietary metrics such as ACO driver and contract tiering. The PlayBook also includes U.S. ACO footprint maps and an exploration of ACO activity as it relates to therapy areas and unified formularies.