Optimal Investment Policies for Defined Benefit Pension Funds

This paper analyzes optimal investment policies for pension funds of a defined benefit (DB) type. The nature of a DB fund induces a natural modeling of preferences being of the mean-downside risk type. With compensation for inflation as an explicit goal of a pension fund, a natural reference point for the risk measure is the future (indexed) value of the liabilities. Results are presented for different levels of inflation uncertainty and its correlation with stock returns. The optimal decision rules show increased risk-taking for funding ratios moving away from the discounted value of the reference point. Furthermore, it is shown that the outcomes are comparable with those using a mean-downside deviation criterion. We provide intuition for the results and compare the outcomes with actual investment policies of six large Dutch pension funds.