We explore the implications of alternative methods of discounting future pension outlays for the valuation of funded pension liabilities. Measured liabilities affect the asset–liability ratio of pension funds and, thereby, their policies. Our framework for analysis is an applied many-generation OLG model describing a small open economy with heterogeneous agents and a two-pillar pension system (with pay-as-you-go and funded tiers) calibrated to that in the Netherlands. We compare mark-to-market discounting against various alternatives, such as discounting against a moving average of past market curves or a curve that is constant over time. The pension buffer is stabilized by adjusting indexation and contribution rates in response to demographic, economic and financial shocks in the economy. Mark-to-market valuation of liabilities produces substantially higher volatility in the pension buffers, but it also generates slightly higher aggregate welfare.