Apple Inc. is the world's most valuable company, potentially the best known brand on Earth, could pull in $50 billion in profit this year and has seen its stock price increase nearly 500% since 2007.
Yet when it comes to the Fortune 500 list, Apple isn't even in the top 10. Or the top 15. In fact, Apple comes in at a lowly 17th place.
That's because Fortune compiles the list in order of firms' total revenue -- the amount of money they pull in each year from sales, before they subtract the often many billions they spend to make those sales: the costs of labor, production, marketing and other necessities. For many of the largest and most established firms, those costs can be very large and can eat deeply into revenue until there's not a lot left to call profit.
But revenue can also be a useful, if rough, indicator of a company's size. Oil giant Exxon Mobil, No. 1 on Fortune's list, has more than 10,000 locations around the world, while Apple has only 363 retails stores. Wal-Mart (No. 2), has 2.2 million employees. Apple has around 60,000.