For 45 years, Fortune Magazine has been ranking the largest companies in the United States. The result is their annual Fortune 500 list. Sometimes people will refer to the top 100 companies on the list as the "Fortune 100." Essentially, the magazine lists the U.S.-based corporations with the largest revenue in the past year. Fortune calculates revenue using publicly available data, therefore private companies (those whose stock is not traded on a public market) are excluded. U.S. subsidiaries of foreign companies are also excluded. Fortune 500 companies are among the biggest, most profitable, and most powerful companies in America. We're talking serious blue-chips with vast holdings, like Exxon Mobil (ranked #1 on the Fortune 500 for 2001), General Electric (#5), and Philip Morris (#10). Talk about profits -- the top company on the list made over $210 billion in revenues! But even the bottom end of the Fortune 500 list isn't too shabby. Newspaper conglomerate Knight-Ridder (ranked #499) and wireless technology company Qualcomm (#500) pulled in over $3 billion each. That's still a respectable sum, especially in a weak economy. (This is taken verbatim from "Ask Yahoo" - http://ask.yahoo.com/20020122.html