Much of the empirical research on mutual funds has rather significant implications for mutual fund investors. Unfortunately, many mutual fund investors have probably never heard about these research results or their implications. They probably, however, have heard some rules-of-thumb or guidelines from their brokers or peers about how to select a particular fund. The purpose of this note is to identify the selection criteria investors seem to use in their buying and selling of mutual fund shares once they have selected an investment objective. That is, do investors select mutual funds based on what I will call “efficient market” criteria (whether or not they are familiar with this literature), or do they use other factors? The criterion I use to measure selection by mutual fund investors is the annual net sales ratio, which is gross sales less redemptions divided by total assets at the start of the year.