This study provides evidence that, when “hard” freezing their defined benefit pension plans, employers select downward biased accounting assumptions to exaggerate the economic burden of their benefit plans. Downward biased expected rates of return and discount rates allow managers to increase reported pension expenses and, for discount rates, allow managers to increase reported pension liabilities. We find that prior to the Sarbanes-Oxley Act, both rates are downward biased when firms freeze their plans, whereas after SOX the bias is lower. This finding is consistent with managers opportunistically biasing pension estimates to obtain labor concessions during periods of reduced regulatory scrutiny.