A mutual fund is a type of investment vehicle that pools money from many investors to purchase securities like stocks, bonds, and other assets. The money collected is invested in capital market instruments and managed by professional fund managers, providing diversification and lower costs than direct investing for individual investors. There are several types of mutual funds including open-end funds, closed-end funds, unit investment trusts, as well as funds classified by their principal investments like money market funds, bond funds, stock funds, and hybrid funds.