How do pension fund trustees deal with demographic and economic shocks? We examine this issue by using a vignette study among pension fund trustees in the Netherlands. Trustees show asymmetric reactions to shocks in the level of reserves of pension funds. Pension premiums are upwardly flexible but trustees are reluctant to decrease premiums. Asymmetries are also revealed by choices regarding the inflation indexation of benefits and changing real (defined) benefits. Asymmetry is not visible in the policy responses to demographic shocks: increases in life expectancy are reflected by taking structural measures for a defined benefit contract: raising pension premiums and the pension age. Furthermore, trustees allow their choices to be affected by the forces of social comparison: the reserve position of their fund compared to the position of other funds has a significant influence in choosing pension fund policy instruments. Keywords: pension funds; finance; governance; behavioural economics.