Just as a car salesperson uses the "blue book" to gauge the approximate price for a newly acquired vehicle, you can use market benchmarks to gauge the approximate performance of your mutual fund investments. Each market index tracks a representative sampling of stocks, bonds, or other securities that may be similar to the holdings in your investment portfolio.
Often tracked in financial websites and newspapers, benchmarks can be especially helpful to individual investors by offering a framework whereby they can evaluate the risk and return history of their own investments. The important consideration to keep in mind is that, when using benchmarks to compare to your investments, you should always compare apples to apples. In order to accurately do this, it helps to be familiar with a variety of benchmarks and the sectors and asset classes they track.