A look at the calls made by Warren Buffett’s conglomerate in the fourth quarter. : Berkshire Hathaway Inc. (BRK.B), the conglomerate run by billionaire investor Warren Buffett, sold some of its giant stake in Apple Inc. (AAPL), called it quits on Oracle Corp. (ORCL) and used some of its freed-up capital to top up on bank stocks in the last three months of 2018. The firm’s hotly anticipated 13F filing revealed that it was eager to buy into financials after a sector-wide selloff.