Warren Buffett's Berkshire Hathaway Inc. BRK BRK unloaded 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. GOLD, according to 13F filings with the Securities and Exchange Commission for the period ended Jun 30, that were released Friday afternoon.