The only two direct AI investments held in Berkshire Hathaway's portfolio are Apple and Amazon (AMZN 1.26%). Despite trimming his exposure to the iPhone maker considerably over the past year, Apple remains Berkshire's largest position -- currently worth about $63.6 billion. Amazon is a considerably smaller position, worth roughly$2.2 billion at current market prices. Buffett is not known as a technology investor, but even his portfolio has some exposure to the artificial intelligence (AI) megatrend. Warren ...