Department of Economics, University of California, Irvine, California 92697-5100, USA.
Appl Health Econ Health Policy. 2010;8(3):155-65. doi: 10.2165/11535510-000000000-00000.
The debate on US healthcare reform has largely focused on the introduction of a public health plan option. While supporters stress various beneficial effects that would arise from increased competition in the health insurance market, opponents often contend that a public plan would drive insurers out of the market and potentially lead to the 'collapse' of the private health insurance industry.
To contribute to the US healthcare reform debate by inferring, from financial market data, the effect that the public option is likely to have on the private health insurance market.
The study utilized daily data on the price of a security that was traded in a prediction market from June 2009 and whose pay-off was tied to the event that a federal government-run healthcare plan - the 'public option' - would be approved by 31 December 2009 (100 daily observations). These data were combined with data on stock returns of health insurance companies (1500 observations from 100 trading days and 15 companies) to evaluate the expected effect of the public option on private health insurers. The impact on hospital companies (1000 observations) was also estimated.
The results suggested that daily stock returns of health insurance companies significantly responded to the changing probability regarding the public option. A 10% increase in the probability that the public option would pass, on average, reduced the stock returns of health insurance companies by 1.28% (p < 0.001). Hospital company stock returns were also affected (0.9% reduction; p < 0.001).
The results reveal the market expectation of a negative effect of the public option on the value of health insurance companies. The magnitude of the effect suggests a downward adjustment in the expected profits of health insurers of around 13%, but it does not support more calamitous scenarios.
美国医疗改革的争论主要集中在引入公共医疗计划选项上。虽然支持者强调了在健康保险市场竞争加剧的情况下会产生各种有益影响，但反对者常常认为，公共计划将迫使保险公司退出市场，并可能导致私营医疗保险行业“崩溃”。
通过从金融市场数据中推断公共选择对私人健康保险市场可能产生的影响，为美国医疗改革辩论做出贡献。
本研究利用了从 2009 年 6 月开始在预测市场上交易的一种证券的每日价格数据，其收益与联邦政府运营的医疗保健计划（“公共选择”）在 2009 年 12 月 31 日前获得批准的事件挂钩（100 个每日观测值）。这些数据与健康保险公司的股票回报数据（1500 个观察值来自 100 个交易日和 15 家公司）相结合，以评估公共选择对私人健康保险公司的预期影响。还估计了对医院公司的影响（1000 个观察值）。
结果表明，健康保险公司的每日股票回报明显对公共选择的概率变化做出了反应。公共选择通过的概率增加 10%，平均而言，健康保险公司的股票回报会降低 1.28%（p<0.001）。医院公司的股票回报也受到影响（降低 0.9%；p<0.001）。
结果揭示了市场对公共选择对健康保险公司价值产生负面影响的预期。影响的幅度表明健康保险公司的预期利润将下调约 13%，但并不支持更灾难性的情景。
