A mutual fund is a diverse holding of stocks that are managed on behalf of the investors that buy into the fund. A mutual fund allows an investor to take advantage of a diversified portfolio without having to invest a large sum of money.

What is the advantage of a diversified portfolio? It offers protection against rapid market losses of any one particular stock. If a portfolio is spread across 20 stocks, if any one of those stocks quickly loses value the effect is less than if the portfolio consisted of that one stock by itself.