When OpenAI’s board fired Sam Altman late last year, Microsoft, which has invested billions in the AI lab, played its trump card. CEO Satya Nadella extended Altman and all OpenAI employees an open invitation to set up a new AI lab inside Microsoft. With the threat hanging over their heads, OpenAI’s board reinstated Altman, and the dissenting directors resigned. OpenAI—whose AI technology powers many Microsoft products—was whole again. It’s not Nadella’s only shrewd move. In March, Microsoft said it would hire staff from buzzy AI startup Inflection, including its star co-founder Mustafa Suleyman, to build a large language model of Microsoft’s own. The move increases the giant’s leverage over OpenAI, and indicates that, in the battle for AI supremacy, big tech companies with mammoth computing power may prevail over the smaller labs where the AI revolution began.