Simulation of pension plan supplemental cost based on withdrawal rate interpolation and different benefit

Abstract

One factor that affects the supplemental cost is the probability that a participant will survive in employment to the retirement age. The probability depends on the mortality rate, the disability rate, the withdrawal rate, and the normal retirement rate. All of the rates are presented in one-year interval except the withdrawal rate. This paper uses the cubic spline interpolation to get the withdrawal rates at one year intervals, whereactuarial calculation method used is Projected Unit Credit (PUC), and pension benefits are calculated using two assumptions, namely the final average and the carrier accrued salary. The interpolation results show that first, the probability of withdrawal at the age of 25 for participants entering the pension program at the age of 20 differs from ages of 21, 22, 23, and 24. Likewise the probability of withdrawal at 30 years of age for participants entering a pension program at the age of 25 is different from ages 26, 27, 28 and 29. The same applies to other ages. The younger the age enters the pension program, the greater the unfunded liabilities that can arise. The unfunded liabilities for the final salary benefit assumption is smaller than the carrier average salary benefit assumption. The unfunded liabilities for entry at a 1-year interval are greater than 5-year intervals.