A mutual fund is a type of professionally managed collective investment vehicle that pools money from many investors to purchase securities. While there is no legal definition of the term “mutual fund”, it is most commonly applied only to those collective investment vehicles that are regulated and sold to the general public. They are sometimes referred to as “investment companies” or “registered investment companies.” Most mutual funds are “open-ended,” meaning investors can buy or sell shares of the fund at any time. Hedge funds are not considered a type of mutual fund.