The USA2000 or Russell 2000 is a market-capitalization weighted index comprised of 2,000 small-cap U.S. stocks. It is often used as a benchmark for the health of small businesses in America. Because of its broad listings some investors prefer it to other indices that are more focused on a specific sector. The 2,000 companies are taken from the bottom of the Russell 3000, an index that includes roughly 98% of all the publicly listed U.S. companies. The Russell 2000 is also considered an important bellweather for the U.S. economy since it is focused primarily on domestic companies.