Market Structure and the Performance of the U.S. Health Insurance Marketplace: A State-Level Analysis

Abstract

Health insurance premiums have more than doubled over the last ten years, with some suggesting that this may be the result of the high market concentration in the health insurance industry. In this paper, we conduct a state-level analysis in which we examine the health insurance marketplace, the degree of market concentration, and health insurance costs across states. We generally find that the barrier to entry into health insurance market is relatively low, as witnessed by the increase in the number of insurers operating in most states over the sample period; accordingly, the extent of market concentration has declined in recent years. We also find evidence of a positive relation between market concentration and insurer profits.