Warren Buffett's Berkshire Hathaway Inc. (BRKA)(BRKA) unloaded a more than a quarter of its stake in Wells Fargo & Co. (WFC) and about 61% of its position in JPMorgan Chase (JPM), while acquiring a new position in Barrick Gold Corp. (ABX.T), according to 13-F filings with the Securities and Exchange Commission for the period ended Jun 30, that were released Friday afternoon.