It's the club every entrepreneur wants to join, but getting into the Fortune 500 isn't easy. A company has to mature well beyond its start-up years to reach the revenue threshold, $4.825 billion for this year's list. Of course, most never make it. The few companies that do make the list share five crucial traits:
Wal-Mart retook the top spot, Berkshire Hathaway made the top five, and Apple grew enormously.