NEW YORK (TheStreet) -- Warren Buffett of Berkshire Hathaway has been reluctant to invest in the common shares of top Wall Street players like JPMorgan and Goldman Sachs. Still, by way of Berkshire's prolific M&A activity, Buffett is helping to turn his top bank holding, Wells Fargo, into a formidable presence in the world of mergers and acquisitions. Berkshire Hathaway, the investing conglomerate run by Buffett, on Thursday announced a $28 billion acquisition of ketchup maker Heinz for $72.50 a share, in what amounts to the Oracle of Omaha's second-largest deal ever. For the Heinz ... Read More