Evaluating the Impact of Health Insurance Industry Consolidation: Learning from Experience.

Research shows consolidation in the private health insurance industry leads to premium increases, even though insurers with larger local market shares generally obtain lower prices from health care providers. Additional research is needed to understand how to protect against harms and unlock benefits from scale. Data on enrollment, premiums, and costs of commercial health insurance--by insurer, plan, customer segment, and local market--would help us understand whether, when, and for whom consolidation is harmful or beneficial. Such transparency is common where there is a strong public interest and substantial public regulation, both of which characterize this vital sector.