You can buy index funds through your brokerage account or directly from an index-fund provider, such as Fidelity. When you buy an index fund, you get a diversified selection of securities in one easy, low-cost investment.

An “index fund” is a type of mutual fund or exchange-traded fund that seeks to track the returns of a market index. The S&P 500 Index, the Russell 2000 Index, and the Wilshire 5000 Total Market Index are just a few examples of market indexes that index funds may seek to track.

The Russell Top 500 Index is a subset of the Russell 1000 Index that includes approximately 500 of the largest companies in the US equity universe based on a combination of their market cap and current index membership.