The Russell 1000 is a stock market index tracking the stock performance of 1,000 companies listed on stock exchanges in the United States that are considered to have large or medium market capitalizations. The Russell 1000 is a subset of the Russell 3000. It is maintained by FTSE Russell and its components are determined via strict rules-based methodology, with an annual rebalancing in late June, the only time new entrants are added to the index.
The index is a public-float-weighted/capitalization-weighted index. The index includes approximately 93% of the total market capitalization of U.S. public companies, with an aggregate market capitalization of more than $80 trillion as of June 30, 2026. The median market capitalization of the components of the index is $17.5 billion and components range in market capitalization from $5.7 billion to $4.8 trillion.
Products linked to the Russell 1000 include index funds as well as derivatives, which are available for trading in many countries with the goal of replicating the performance of the index.Wikipedia