the calculation formula of sinking fund coefficient is: sinking fund coefficient =1÷ ordinary annuity final value coefficient, and sinking fund coefficient is the reciprocal of ordinary annuity final value coefficient. Sinking fund is a fund set aside by an economic entity for a period of time to finance future fund-raising expenses or repay long-term debts.

there are two main ways to form the company's sinking fund: one is to withdraw according to a fixed amount or a certain proportion of bonds issued; The second is to extract according to a certain proportion of after-tax profits or sales revenue. The purpose of establishing a sinking fund is to strengthen the country's financial reserve, realize the balance of financial burden and avoid the risk of financial debt repayment during the peak period of debt repayment.