The Fortune 500 includes 500 companies, ranked by annual revenue.
Fortune created the list to identify the largest U.S. corporations, using revenue from the relevant fiscal year as the ranking measure. It is not a list of 500 publicly traded companies only: privately held businesses can appear when their revenue is publicly available and they meet the ranking criteria.
The number 500 is part of the list’s identity, much like the Fortune 100 and Fortune 1000. The Fortune 100 is a smaller subset, while the Fortune 1000 extends the ranking to twice as many companies. These lists should not be confused with the S&P 500, which tracks selected publicly traded stocks using different eligibility rules and a different purpose.
The list’s membership changes from year to year as revenues, mergers, business conditions, and corporate structures change. What remains constant is the ranking’s basic scope: 500 leading U.S.-based corporations measured primarily by total annual revenue.