What is the name of the U.S. stock index that tracks 2,000 small-cap companies?

The U.S. stock index that tracks 2,000 small-cap companies is the Russell 2000.

Launched by the Frank Russell Company in 1984, the index contains the smallest 2,000 companies in the Russell 3000. That broader index represents roughly 96% of the investable U.S. equity market, while the Russell 2000 focuses on its small-cap segment.

The Russell 2000 is widely used as a benchmark for small-cap mutual funds, exchange-traded funds, and portfolio managers. Because smaller companies can be more sensitive to borrowing costs, consumer demand, and domestic economic conditions, investors often watch it as a gauge of U.S. business activity.

A common mix-up is the S&P 600, which is also a small-cap index but has a different membership list and methodology. The Russell 2000 is not simply any 2,000 companies; it is selected from the Russell 3000 and weighted by free-float-adjusted market capitalization.