When social assistance meets market power: A mixed duopoly view of health insurance in the United States
构建了一个质量差异化的混合双头垄断模型，以美国医疗补助为公共企业，分析其扩张对福利的影响，发现尽管医疗补助效率低下，但扩张仍能改善福利，因为私营企业的市场力量受到约束。
Abstract We develop a mixed duopoly model with quality‐differentiated products. The public firm offers its product for free to eligible individuals, while the private firm chooses its product quality and price to maximize profit. We calibrate the model to health insurance for the U.S. working‐age population, with Medicaid being the public firm. We examine distributional implications of policies that expand Medicaid to various degrees. Despite potentially significant inefficiency of Medicaid, its expansion is welfare improving. Central to these findings is the significant market power of the private firm when left unchecked, which is increasingly disciplined as more individuals become Medicaid eligible.