The Russell 2000 is an index measuring the performance of the 2,000 smallest American companies in the Russell 3000 Index, which is made up of 3,000 of the largest U.S. companies. It is a market-cap weighted index.
Q&A: What is the Russell 2000?

The Russell 2000 is an index measuring the performance of the 2,000 smallest American companies in the Russell 3000 Index, which is made up of 3,000 of the largest U.S. companies. It is a market-cap weighted index.