Founded in 1988, the asset-management firm has grown into the world's largest, thanks to a slew of deals, including the purchases of Merrill Lynch Investment Managers in 2006 and Barclays Global Investors in 2009. Last summer's retirement of co-founding partner and vice chairman Sue Wagner, who oversaw BlackRock's M&A business, signaled an end to the firm's acquisition strategy. Chairman and CEO Larry Fink is now restructuring the company, hoping to spur investor deposits instead of large-scale acquisitions. BlackRock (No. 286) ended 2012 on a high note: The company closed the year managing a record $3.792 trillion in assets.
Wal-Mart retook the top spot, Berkshire Hathaway made the top five, and Apple grew enormously.