Market landscape and insurer-provider integration: the case of ambulatory surgery centers.

Insurer-provider integration is a new form of vertical integration, with increasing prominence in health care markets. While there are potential benefits from tighter alignment between providers and payers, risks of perverse impacts on health care markets loom large. Yet, little is known about this new wave of consolidation, which limits options for policy or regulatory responses. We focus on a dominant insurer's acquisitions of ambulatory surgery centers (ASCs) to document the growth and geographic spread of these ownership events. We found that a diverse swathe of the United States has experienced an insurer-led ASC takeover. The acquisitions are also more frequently in areas where the insurer holds a higher enrollee market share at baseline, although a linear prediction of the likelihood of ASC acquisition shows a more nuanced picture.