** Shares of AI software firm C3.ai up 18% at $31.30, a more than four-month high

** Company announces tie-up with Microsoft to accelerate adoption of enterprise AI on Microsoft Azure

** "The agreement positions Microsoft as the preferred cloud provider for C3.ai offerings and establishes C3.ai as preferred AI application software provider on Microsoft Azure" - C3.ai

** Since first entering an alliance in 2018, MSFT and C3.ai have partnered to deliver enterprise AI solutions to companies such as Dow, Shell and Nucor, among others

** Including session's move, AI up about 9% YTD

(Reporting by Ragini Mathur)

((Ragini.Mathur@thomsonreuters.com;))