Recent buyout fundraising: $10.1 billion

Description: Apollo's founder and chairman, Leon Black, served up a double shot of dealmaking in December: In the same week he acquired Realogy, owner of Coldwell Banker and Century 21, for $9 billion, followed by a $27.4 billion deal to purchase Harrah's Entertainment together with Texas Pacific Group. The latter club deal was an exception, because the firm, whose name derives from the Greek god of light and healing, normally works alone. Black, who spent the 1980s running mergers and acquisitions at Drexel Burnham Lambert, is a master of labyrinthine debt financing. And his ability to heal broken companies has resulted in compound annual returns greater than 40 percent since the firm's inception in 1990. Some 90 percent of Apollo's investments have generated positive returns.

Boldface advisors: Adam Aron, former CEO of Vail Resorts. He built the mountain into the pound sterling of ski towns.

Fun fact: Apollo's penchant for distressed assets extends to office space. Its headquarters, which have unobstructed views of New York City's Central Park, are located in the former digs of Tyco.