Safe Withdrawal Rates, Optimal Retirement Portfolios, and Certainty-Equivalent Spending

Abstract

We test a parametric retirement spending strategy incorporating constant spending, variable spending, smoothing, and mortality updating, which reduces to common strategies with suitably chosen parameters. We examine the relationship between spending and shortfall risk over a large universe of parameters and portfolios. Using certainty equivalent spending with constant relative risk aversion, we observe that risk-neutral retirees will maximize lifetime spending, while highly risk-averse retirees will tend toward a fixed spending strategy, such as the Bengen ‘4% rule’. We discuss how practitioners and retirees with risk aversion between these extremes can identify optimal strategies balancing income and shortfall risk.