职工基本养老保险个人账户长寿风险及其估计

中国已进入长寿时代，长寿风险是学界研究各类养老金制度持续关注的重点。现行职工基本养老保险制度采用社会统筹与个人账户相结合的模式，这一特殊的制度设计使个人账户长寿风险更值得重视。从风险形成及传导机理来看，风险源主要是个人账户制度设计存在缺陷，在记账利率虚高、待遇捆绑调整等政策因素的影响下，人口老龄化导致基金缺口的效应进一步放大。未来全国个人账户基金收支平衡面临较大压力，将对职工基本养老保险制度整体的可持续运行构成挑战。建议科学确定个人账户记账利率，改革养老金计发办法，建立计发月数动态调整机制，通过“统账分离”将个人账户改造为职业年金，促进多层次养老金体系的发展。

A Study on the Longevity Risk of the Personal Account of Basic Pension Insurance for Employees and Its Estimation

Since 1997, the basic pension insurance for employees in China has followed the model of “social pooling and personal accounts”. After more than 20 years of operation, the number of beneficiaries has continued to expand, and the level of benefits has increased year by year, which has effectively guaranteed the basic livelihood of retirees. But at the same time, we need to note that the financial sustainability of employee basic pension insurance has begun to arouse the attention of the whole society. Especially in recent years, China’s problem of population aging has been growing, the average life expectancy has continued to increase, and the employee’s basic pension insurance dependency ratio has been decreasing year by year. The pay-as-you-go pension insurance system is facing challenges. The original intention of setting up personal accounts was to make up for the inadequacies of the pay-as-you-go model for the aging population, and to resolve longevity risks through a model of fund accumulation. Therefore, it is necessary to re-evaluate the policy design and practical operation effects of the basic pension insurance personal accounts for employees, especially the role it played in dealing with longevity risks. This paper starts from the design of the personal account system of basic pension insurance for Chinese employees and systematically expounds the formation and transmission mechanism of longevity risks for personal accounts. The so-called longevity risk refers to the financial risk of the fund caused by the inconsistency between the actual lifespan of the insured group and the life expectancy set by the mechanism design of current personal account. In the event of personal account longevity risk, the “risk source” is mainly a series of flaws in the design of the personal account system. The “risk transmission path” is mainly due to such factors as life span elongation and the personal account foundations not being able to pay off. “Risk amplification station” is mainly in the operation of the system, when a series of policies have led to accelerated consumption of personal account deposits. We have established an actuarial model that characterizes the longevity risk of personal accounts leading to fund risk. Taking a “standard insured person” as the object of analysis, with the aid of actuarial analysis methods, it is estimated that when the fund’s investment return rate is 4%, the personal account fund can pay up to the age of 74 for the insured person who retires at the age of 60. The insured person of 75 or older will be paid out of the pooling fund for the personal account treatment. When the fund’s investment return rate is 8%, the personal account fund can pay until the age of 84. The longevity risk of personal accounts arises from the combined effect of multiple reasons. This paper further describes the effects of policy adjustment factors and demographic environment factors on the longevity risk of personal accounts. The main conclusions are: (1) If the actual investment return rate of the fund is 8% and the bookkeeping interest rate is 4%, the consumption of personal account fund balance will be greatly accelerated, and the time when personal account balance is exhausted will be advanced from 75 to 65. (2) If the basic pension and the personal account pension are adjusted together, the time when the savings in the personal account are exhausted will be advanced from the age of 75 to 71. (3) In accordance with the trend of current population aging, other factors aside, the growth of the personal account fund gap is relatively stable. (4) If the above factors are combined, the personal account fund gap will increase from 661.922 billion yuan in 2020 to 3,090.702 billion yuan in 2035, and the ratio of the gap to basic pension expenditure will rise from 17.4% in 2020 to 22.9% in 2035. This article proposes the following policy measures to deal with the longevity risks of personal accounts: (1) Establish a reasonable method for adjusting the interest rate of personal accounts. (2) Strictly control the increase in personal account pension standards. (3) Establish a dynamic adjustment mechanism of the number of months for personal account payment in accordance with age, gender and time. In the era of longevity, improving the personal account system will better promote the sustainable operation of the basic pension insurance for employees.