The Russell 2000 Index is a stock market index that tracks the performance of the 2,000 smaller businesses that make up the Russell 3000 Index. Because of its concentration on smaller businesses that target the U.S. market, the Russell 2000, which is administered by London's FTSE Russell Group, is frequently referred to as a leading indicator of the American economy. Many investors compare the success of small-cap mutual funds to the movement of the index since they view the index as a better reflection of opportunities in that entire sub-section of the market than in the other main indices (Dow Jones, S&P 500 and Nasdaq 100). That's because those narrower indices may have biases or be exposed to more stock-specific risks which might affect their performance overall.