Multimarket Contact in Health Insurance: Evidence from Medicare Advantage*
研究了多市场接触对联邦医疗保险优势计划价格和质量的影响，发现多市场接触增加导致保费上升、高质量计划减少，支持了相互容忍假说。
Many industries consist of large firms that compete in multiple geographic markets. Such overlap, defined as multimarket contact (MMC), may facilitate tacit collusion and soften competition. We examine the effects of MMC on health insurance prices and quality using comprehensive data on the Medicare Advantage (MA) market from 2008 through 2015. Our identification strategy exploits two plausibly exogenous changes to MMC: (1) out‐of‐market mergers; and (2) policy‐driven changes in the benchmark rates of other markets. Our results consistently support the mutual forbearance hypothesis, where we find that prices are significantly higher and high‐quality plans less pervasive as MMC increases.