The Russell 2000 index measures the performance of the equity of small-cap companies that are on the Russell 3000. The Russell 3000 index measures the performance of the largest 3,000 U.S. companies.
The Russell 3000 accounts for about 98 percent of all investable equity and the Russell 2000 accounts for about 10 percent of the Russell 3000. The Russell 3000 offers a more comprehensive view of the entire market. The Russell 2000 is used to accurately gauge the performance of small-cap companies, and ensure the large-cap companies do not dilute performance reporting of the small-cap spectrum. The average 10-year return for the Russell 2000 is 7.7 percent.