OPTIMAL PORTFOLIO, CONSUMPTION-LEISURE AND RETIREMENT CHOICE PROBLEM WITH CES UTILITY

We study optimal portfolio, consumption-leisure and retirement choice of an infinitely lived economic agent whose instantaneous preference is characterized by a constant elasticity of substitution (CES) function of consumption and leisure. We integrate in one model the optimal consumption-leisure-work choice, the optimal portfolio selection, and the optimal stopping problem in which the agent chooses her retirement time. The economic agent derives utility from both consumption and leisure, and is able to adjust her supply of labor flexibly above a certain minimum work-hour, and also has a retirement option. We solve the problem analytically by considering a variational inequality arising from the dual functions of the optimal stopping problem. The optimal retirement time is characterized as the first time when her wealth exceeds a certain critical level. We provide the critical wealth level for retirement and characterize the optimal consumption-leisure and portfolio policies before and after retirement in closed forms. We also derive properties of the optimal policies. In particular, we show that consumption in general jumps around retirement.     

Fiscal and Welfare Effects of Balanced-budget Reforms of Korea’s National Pension System

This paper evaluates the fiscal sustainability of the benchmark pension system in Korea, which will come into effect in 2028 following the 2007 pension reforms, and the welfare effects of pension reforms aimed at a balanced budget over the life cycle. To this end, we measure the lifetime pension deficit, i.e. the difference between total pension benefits and total pension contributions in an individual’s lifetime. We find that the benchmark pension system is expected to run an average lifetime deficit of 22.36 million won (approximately $22,360), and the current pension fund is unlikely to finance the sum of future deficits. The optimal pension reform for the zero average lifetime deficit reduces social welfare by as much as a 2.06% fall in consumption and is characterised with the contribution rate of 20.3% and an average replacement rate of 66.4%. These values are much higher than the respective benchmark values, 9% and 40%, because the increase in pension benefits, combined with the increase in pension contributions, can reduce the income inequality due to the progressivity of pension benefits and the proportionality of pension contributions.