It is well established in the literature that the young and healthy are more inclined to switch health plan, given the opportunity. In countries where risk-adjusted capitation payments are used to create a level playing field for the competing health plans, as is the case in The Netherlands, it is important to determine whether plans could exploit such selective switching to gain unfair advantage. This study analyses whether various risk-adjustment models are capable of compensating adequately for selective switching in the Dutch sickness fund sector. Data concern information on health care expenditures, demographics and indicators of chronic diseases for 10 million members from 21 funds. Results indicate that switchers in 2000-2001 had expenditures that were around 40% below average in 1994-2002, confirming that movers are ‘good’ risks in absolute terms. However, after taking into account that these people are younger and healthier, the risk-adjusted payments for them nearly equalled actual expenditures. This holds for both people who in fact switched from one fund to another, and for those who were forced by regulation to leave the private insurance sector and who had to choose a sickness fund. Importantly, models using only demographics could not achieve this.