逆向选择条件下带甄别期的最优保险设计  

Optimal Insurance Design in the Screening Period Under Adverse Selection

作　　者：胡振华[1] 孙巧 Hu Zhenhua;Sun Qiao(School of Business,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]中南大学商学院,湖南长沙410083

出　　处：《金融发展研究》2021年第5期44-52,共9页Journal Of Financial Development Research

基　　金：教育部人文社会科学研究青年基金项目“基于演化博弈的我国养老地产产业链升级模式与路径研究:路径构造框架的视角”(17YJC790035)。

摘　　要：为了改善信息不对称对保险市场交易效率的影响,分投保人为两种及两种以上风险类型建立了带甄别期的保险契约模型,指出可以利用投保人在甄别期的风险发生情况来推断投保人的风险类型。带甄别期的保险契约是指:自保险合同生效之日起的一段时间内(甄别期),如果投保人发生风险,保险公司将给予一定的赔偿,甄别期过后,如果投保人再次发生风险,保险公司将不再给予任何赔偿;如果投保人在甄别期未发生风险,而在甄别期之后的剩余保险期发生风险,保险公司仍然给予与上述情况相同的赔偿。证明指出效用最优时带甄别期的保险契约不比R-S传统部分保险契约差,并给出了前者是后者严格帕累托改进的充分条件。此外,对于两种以上风险类型情形,证明了满足对次低风险投保人的激励相容约束是满足对其余高风险投保人激励相容约束的一个充分不必要条件,并给出了相应的充分条件,进一步指出该充分条件的集合恰是带甄别期的保险契约能够产生分离均衡的一个充分条件。最后,以一个算例说明确实存在效用最优时带甄别期的保险契约是R-S传统部分保险契约的严格帕累托改进情形。In order to improve the impact of information asymmetry on the efficiency of insurance market transactions,an insurance contract model in the screening period is developed by dividing the insured into two and more risk types,pointing out that the risk occurrence of the insured during the screening period can be used to infer the risk type of the insured.An insurance contract in the screening period is a period of time from the date of entry into force of the insurance contract(screening period)during which the insurance company will pay a certain amount of compensation if the insured person incurs a risk,after which the insurance company will not pay any compensation if the insured person incurs a risk again.However,if the insured does not incur a risk during the screening period but does so during the remaining coverage period after the screening period,the insurer will still grant the same benefits as described above.The proof points out that the insurance contract in the screening period at utility optimum is no worse than the R-S traditional partial insurance contract and gives a sufficient condition for the former to be a strict Pareto improvement of the latter.In addition,for more than two risk types,it is shown that satisfying the incentive compatibility constraint for the next-lowest-risk policyholder is a sufficient and unnecessary condition for satisfying the incentive compatibility constraint for the remaining high-risk policyholder,and the corresponding sufficient condition is given,and it is further shown that the set of this sufficient condition is precisely a sufficient condition for an insurance contract in the screening period to produce a separation equilibrium.Finally,an arithmetic example is given to show that there does exist a strict Pareto-improvement case of insurance contracts with screening periods at the utility optimum for the R-S traditional partial insurance contracts.

关 键 词：信息不对称 逆向选择 最优保险设计 甄别期 帕累托改进 

分 类 号：F840[经济管理—保险]