What does the Russell 3000 Index Fund measure?

The Russell 3000 Index Fund's goal is to benchmark the entire U.S. stock market by tracking the 3,000 largest stocks that are traded in the United States. These companies represent approximately 98 percent of the U.S. market, according to Russell Investments.

Every year around May or June, the stocks within the Russell 3000 Index are re-evaluated according to their market capitalization, or market value of the company, to determine whether or not they are still one of the top 3,000 publicly traded companies. In addition, if a company becomes ineligible between these evaluation periods, a replacement is not be named until the next evaluation period, according to Investopedia.