Shares of Microsoft Corp. are up 0.8% in premarket trading Monday after the company said that it acquired Semantic Machines Inc., a company that works on "conversational AI" efforts. "Combining Semantic Machines' technology with Microsoft's own AI advances, we aim to deliver powerful, natural and more productive user experiences that will take conversational computing to a new level," Microsoft said in a release. Microsoft already does work in conversational AI with its Cortana virtual assistant and XiaoIce social chatbot. Terms of the deal weren't disclosed. Microsoft shares are up 42% over the past 12 months, while the Dow Jones Industrial Average has gained 19%.