养老资产年金化谜题:风险决策下的年金化价值比较

Annuity Puzzle:the Comparison of Annuitization Value under Venture Decision

随着中国经济增长放缓和人口老龄化加剧,社会养老保险提供的养老金份额呈下降趋势,职业养老金计划呈转向缴费确定型(DC)计划的趋势,养老保障中的长寿风险、投资风险、通胀风险等将更多地由个人承担。虽然相关研究表明,养老资产年金化是退休者的最优选择,但在实践中退休者自愿年金化的比率很低,使人们暴露在巨大的风险之中。那么,是哪些因素通过怎样的渠道影响着人们的年金化决策?如何评价年金化的价值?这些问题成为非常重要的研究课题。在相关文献评述的基础上,将行为经济学中的"累积前景理论"引入传统的精算模型,从个人风险决策的角度衡量年金的价值,并进一步将遗赠动机纳入终身福利价值模型,从风险决策角度测算遗赠动机对年金化决策的影响,并在此基础上考虑保险成本和投资机会成本等现实因素的影响。研究发现:风险决策视角下,年金的累积前景价值低于年金精算中性价值,养老年金不再是个人的最优选择。同时遗赠动机越强的个人越倾向于自我养老,保险成本和投资机会成本也会显著影响个人的年金决策。这些结论使年金需求不足的现象得到了较好的解释。

With economic growth slowing down and population ageing,the pension benefit shares from social insurance have been decreasing,and the occupational pension plans sponsored by employers have been experiencing a transition from DB to DC.The individual will burden more longevity risk,investment risk and inflation risk in old-age security.Although the annuitization of individual assets at retirement has been considered as the optimal choice for retirees,few people would like to annuitize their assets voluntarily.As more and more people are exposed to longevity risk,it is imperative to explore factors affecting people＇s decisions of annuitizaiton and how these factors work.Based upon literature review,this article introduces the cumulative prospect theory of behavioral economics into the traditional actuarial model,and revalues annuities from the view of venture decision.Furthermore,by incorporating bequest motives into the framework of life welfare model,this article calculates the effects of bequest motives,insurance cost and opportunity cost of investment on annuitizaiton decision.The results show that,the cumulative prospect value of annuity is lower than its actuarial neutral value from the view of venture decision,and thus life annuity would not be the optimal choice for the individual.Moreover,people with stronger bequest motives are more likely to choose self-annuitization,and insurance cost and investment opportunity cost also have a significantly negative influence on the annuitization decision.Therefore,the low demand of life annuity can be well explained.