关键词: 养老保险, 个人账户, 三差损, 计发系数, 动态调整

Abstract: The annuity divisor table for the individual account in Chinas Basic Oldage Insurance for Enterprise Employees （BOIEE） has not been revised for nearly two decades，which underestimates the benefit payment period Though China has proposed plan to revise the annuity divisor table，most studies examining the impact of annuity divisor dynamic adjustment only calculated the shortfall resulting from the extension of average life expectancy，without taking into account the shortfall caused by the excessively low actual return rate （ARR） of pension funds
Based on the assumption that the booking interest rate （BIR） is higher than the ARR，this paper decomposes the shortfall of individual account into the “longevity differential loss （LDL）” caused by longevity risk，the “interest differential loss （IDL）” caused by the ARR being lower than the BIR，and the “growth differential loss （GDL）” caused by investment returns being lower than the growth increment of the benefits Thus，the annual deficit of all participants individual accounts can be summarized into three parts，namely，the inservice death return gap，the pension payable gap and the inheritance gap Based on the mortality rates for China predicted in the World Population Prospects 2022 and other assumptions，we have compiled genderspecific and unisex annuity divisor tables that are adjusted every five years
The result indicates that under the scenario where the ARR is lower than the BIR，dynamic adjustment of the annuity divisor can directly reduce LDL，indirectly reduce IDL and GDL In the annual deficit，the inservice death return gap is not affected by the annuity divisor Since the new annuity divisor table only applies to retirees after 2025，there is a lag in the decrease of the pension payable gap，and the inheritance gap will continue to increase Therefore，the annual deficit will first increase and then decrease，with the actuarial present value of the annual deficit predicted to decrease by approximately 52% during the forecast period If the annuity divisor is adjusted while simultaneously raising the ARR to the BIR，all three losses are reduced The inservice death return gap can be gradually reduced to zero，and the actuarial present value of the annual deficit decreasing by approximately 75% Although simultaneously lowering the BIR can decrease the actuarial present value of the annual deficit by approximately 80%，it significantly diminishes participants pension replacement rate There is little difference in annual deficit between genderspecific and unisex annuity divisor tables；however，the latter exhibits a redistribution effect that narrows the gender gap in benefits Thus we recommend that China adopt a dynamically adjusted unisex annuity divisor table in the future while also striving to improve the investment return rate of the BOIEE

Key words: old-age insurance, individual account, three difference losses, annuity divisor, dynamic adjustment