Retired people need life annuities – contracts that offer a stable income stream for as long as they live – to insure against the risk of outliving their wealth. If there were no longevity risk – that is, if the probability of dying at each age in the future were reliably known – then pension funds could easily offer life annuities to large numbers of people by investing their assets in bonds of various maturities in order to pay out just the right amount each year.
退休人员需要生活年金——一份在他们有生之年提供稳定收入来源的合同——以防止他们的财产不够他们长寿生活的风险。如果没有长寿风险——即，能获知每个年龄可靠的死亡可能性数据——退休金基金就能将很多人的资产按照不同的到期时间投资，每年付出正正好好的数额，这样就很容易向他们发放生活年金。