Warren Buffett's Berkshire Hathaway (BRK.B) has too many large positions in high-cost businesses, according to a hedge fund manager who once owned Buffett's stock but has no interest in holding it again. Jeffrey Matthews, General Partner at RAM Partners, pointed to Buffett's investments in companies like IBM (IBM), American Express (AXP), Walmart (WMT) and NetJets. Matthews also said he did not like Buffett's purchase of Precision Castparts, which he believes Buffett paid a high premium for. Matthews said the days of Berkshire Hathaway stock outperforming the broader market are over. 'Buffett likes to buy moats and own them for a long period of time,’ said Matthews. ‘He started to have this portfolio of investments, or moats, that were breaking. And that’s what really bothered me.’ TheStreet's Rhonda Schaffler has details from Wall Street.