Health Cost Risk: A Potential Solution To the Annuity Puzzle
研究发现健康成本风险会降低退休时的最优年金需求，因为退休初期医疗支出可能较大，人们需要先积累流动性资产。这解释了现实中人们为何不买足年金，而允许退休后追加年金最多可带来2.5%的福利提升。
We find that health cost risk lowers optimal annuity demand at retirement. If medical expenses can be sizeable early in retirement, full annuitisation at retirement is no longer optimal because agents do not have enough time to build a liquid wealth buffer. Furthermore, large deviations from optimal annuitisation levels lead to small utility differences. Our results suggest that health cost risk can explain a large proportion of empirically observed annuity choices. Finally, allowing additional annuitisation after retirement results in welfare gains of at most 2.5% when facing health cost risk, and negligible gains without this risk.