Heterogeneity effects on the management of retirement fund

This article studies the importance of plan members’ heterogeneity to the management of defined benefit (DB) pension fund. We propose a new multi-member model of DB pension fund that allows for heterogeneity in plan members’ retirement ages, salary growths and other characteristics. We first solve analytically for optimal management strategy and show that the sponsor’s supplementary contribution and the fund’s allocation in risky assets are determined by the cross-product between the fund’s expected retirement liabilities and some heterogeneity-adjusted discount factors. We then demonstrate that the presence of heterogeneity can have a significant influence on the optimal management strategy and that a management decision made while ignoring heterogeneity will be suboptimal. The knowledge of desirable and undesirable effects of heterogeneity that we uncover in this article also provides implications to the grouping of fund members. Introducing a presence of young member whose salary is positively correlated with the risky asset and avoid stacking members with negative correlations will all help the management.