Since 1955, when the first FORTUNE 500 was created, more than 1,800 companies have appeared on the list. Many of these companies have changed names over this period, owing to mergers, acquisitions, and bankruptcies. Other companies have gone private, or simply changed their names.
Companies are listed by the name with which they were associated in 2005, or at the time of their most recent list appearance before that. FORTUNE 500 companies that have been acquired by other FORTUNE 500 companies are listed under the name of the acquiring company. Rankings have been revised to reflect corrections in data.