Mutual fund companies charge investors fees that can lower their overall returns. Load funds, aimed at less knowledgeable investors, have higher expenses than no-load funds for the same type of investment. This cost difference has been increasing since the 1990s. Load funds also often charge extra fees that can eat into returns, especially for funds that are closed to new investors. So, if you invest in load funds, you might end up paying more and getting less in return over time.