Berkshire Hathaway, the massive enterprise with its hand in various industries, also owns a sizable public equities portfolio. Directed by legendary investor Warren Buffett, the conglomerate has done a remarkable job compounding capital.Everyday investors can find potential ideas by looking at what the Oracle of Omaha owns. There's one business that Berkshire has a $37 billion stake in -- and it might just continue its winning ways.Here are three reasons why you should buy this top financial stock right now ...