It is often argued that European citizens are not able to fully benefit from the single market for investment funds, on the basis that the cost of UCITS is higher than the cost of mutual funds in the United States (US). In this Market Insights, we analyse this question by carrying out a detailed comparison of the cost of UCITS and US mutual funds, taking into account the various ways of calculating costs as well as the differences between Europe and the US in the way investment funds are distributed.