This paper provides a detailed examination of individuals' active participation in a new public and mandatory defined contribution pension system. The new pension system was launched in the fall of 2000 and entitles Sweden's workforce of 4.4 million individuals to invest part of their individual pension account in mutual funds. Our findings show that the system is associated with a reversed investment behavior compared with studies of 401(k) plans; that is, individuals tend to make their own investment decisions. Contrary to US studies, we also find that women and younger individuals are more likely than men and older individuals to make an active investment decision.