After-tax performance data for non-qualified nuclear decommissioning trusts are not readily available. Applying a portfolio's turnover rate, coupled with the appropriate tax rates, to pretax returns does not produce valid after-tax return data. The exemption of 70% of dividend income from taxes further complicates the computation. A model that includes a utility's level of taxation and time horizon to decommissioning demonstrates how after-tax returns can be computed to permit meaningful comparisons of equity managers with diverse styles.