保险需求悖论的解释——来自中国汽车险市场的实证研究

经典的保险需求模型认为绝对风险规避系数递减时保险是一个劣质品,也就是说保险需求会随着财富水平的上升而下降,但这一结论与许多现实的保险行为不符。本文从损失和财富的关系角度出发对经典模型进行了扩展,讨论了在损失随财富变化时的保险需求变化,对保险需求的悖论进行了解释。论文还采用国内汽车险市场的微观数据对拓展模型进行了实证研究,结果显示车险投保人的个人财富与其所选择的保险金额、投保比率以及索赔金额之间存在着显著的正相关关系,检验表明模型的假设和结论具有很好的解释现实的能力。

Understanding the Paradox of Insurance Demand:Evidence from China's Auto Insurance Market

Insurance demand is one of the most important theoreti-cal issues in insurance research, and related empirical studies are an active and fruitful field. The classic model of insurance demand was developed by Mossin (1968), who showed that insurance products are an inferior good for individuals with decreasing absolute risk aversion; that is, insurance demand decreases as the wealth level increases. However, this model is not consistent with the observed behavior in the insurance market because the wealthy tend to buy more insurance. One of the most important assumptions in Mos-sin's model is that the loss severity is independent of wealth. In this article, we extend the Mossin model by relaxing this assumption. We consider the possibility that the loss severity may depend on the level of wealth to resolve the apparent inconsistency of increased insurance purchase by the wealthy. We show that insurance demand may increase with the level of wealth if the loss severity is pro-portional to the wealth level. We empirically test the model using data from the domestic auto insurance market. We investigate the relationship between the insurance amount or claim amount and the policyholder's wealth level in an ordinary linear regression model, and investigate the relationship between insurance coverage and the wealth level in a Probit model. It is shown that the policyholder's wealth level is significantly positively correlated with his insurance amount, insurance coverage and claim amount, which is consistent with our model predictions. Despite the fact that the model proposed in this paper provides a reasonable explanation of the empirical findings regarding insurance demand, we are aware that there could be other explanations, such as the existence of background risks or the irrationality of policyholders, which we leave for future studies.