Russell 2000 Index An index measuring the performance of the 2,000 smallest companies in the Russell 3000 Index, which is made up of 3,000 of the biggest U.S. stocks. The Russell 2000 serves as a benchmark for small cap stocks in the United States. Investopedia Says: The weighted average market capitalization for companies in the Russell 2000 is about US$1 billion and the index itself is considered to be the benchmark for all small cap mutual funds. Related Terms: Market Capitalization Passive Management Russell 2500 Index Russell 3000 Index Russell Microcap Index Russell Midcap Index Russell Top 200 Index Small Cap Standard & Poor's 500 Index - S&P 500 Wilshire 5000 Total Market Index - TMWX |