The Division of Economic and Health Policy Research undertakes independent research and data analyses to produce unique AMA socioeconomic advocacy resources, such as the AMA’s Competition in Health Insurance study and AMA Policy Research Perspectives, for use by AMA physician leaders and staff, the Federation, physician members, and policymakers. The Division also conducts economic analyses and develops advocacy resources (e.g., SGR “gap” chart, state-level impacts, budget scoring analyses) in direct support of AMA federal, state, and private sector advocacy agendas (e.g., Medicare/SGR reform; medical liability reform, antitrust reform). The following reports come from this AMA unit and/or other AMA units working on key advocacy topics.
By José R. Guardado, David W. Emmons and Carol K. Kane
Published in Health Management, Policy and Innovation, 1(3) 16-35, July 2013.
In this paper, we examine the association between market concentration and prices in the health insurance industry. Specifically, we conduct a case study of a large merger between health insurers— UnitedHealth Group and Sierra Health Services—which caused a shock to market concentration in Nevada's health insurance markets. Using a novel data set on health plan attributes, we exploit that natural experiment to obtain estimates of the association between the merger and premiums. The treatment group consists of health plans in markets affected by the merger, and the control group consists of health plans in similar markets that were not affected. Using a difference-in-difference propensity score matching estimator, we compare the change in premiums of health plans in the treatment group to the premium change in the controls. We find that premiums in Nevada markets increased by 13.7 percent after the merger relative to the control group. Our findings suggest that the merging parties exploited the market power gained from the merger.
This is the 12th edition of the AMA's Competition in Health Insurance: A Comprehensive Study of U.S. Markets. This study presents new data on the degree of competition in different regions of the country. It is intended to help researchers, policymakers, and federal and state regulators identify areas where consolidation among health insurers may cause competitive harm to consumers and providers of care. It reports commercial health insurance market shares and concentration measures (HHIs) for 386 metropolitan areas, the 50 U.S. states and the District of Columbia. The U.S. Department of Justice (DOJ) and Federal Trade Commission (FTC) use this type of information to assess the anti-competitive effects of horizontal mergers. The 2013 Update is based on HealthLeaders-InterStudy’s Managed Market Surveyor, with enrollment data as of January 1, 2011.
Key findings in this edition are that, based on the DOJ/FTC Horizontal Merger Guidelines, 71 percent of the 386 MSAs studied were highly concentrated (HHI>2,500). Additionally, in 89 percent of MSAs, at least one insurer held a commercial market share of 30 percent or greater.
In short, most commercial health insurance markets in the U.S. are highly concentrated. The results of this study should prompt federal and state antitrust authorities to more vigorously examine the anti-competitive effects of proposed mergers between health insurers.
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