The UK's Competition and Markets Authority (CMA) is considering a merger probe into the partnership between Microsoft Corp (NASDAQ:MSFT) and OpenAI. The CMA is assessing potential competition issues in the UK following their collaboration. Microsoft, as the principal investor, has invested $13 billion in OpenAI. The partnership has integrated OpenAI's AI innovations into Microsoft's enterprise tools, while OpenAI uses Microsoft's cloud services. Despite the close ties, Microsoft does not control OpenAI, as evidenced by the recent reinstatement of OpenAI's CEO Sam Altman after his ousting. Microsoft's president, Brad Smith, asserts that the partnership fosters AI innovation and competition, with Microsoft being a nonvoting observer on OpenAI's board. MSFT shares are slightly down in premarket trading.