Microsoft is quietly replacing OpenAI with its own AI in Excel and Outlook

Wed, 08 Jul 2026 00:00:00 +0800

Every week, tens of thousands of AI prompts inside Excel and Outlook are now handled by Microsoft’s in-house MAI model — not by OpenAI’s GPT or Anthropic’s Claude, according to Bloomberg.

That’s still a small fraction of Microsoft’s total AI usage across its products. But it signals a deliberate long-term shift. Over the past year, Microsoft has relied on its deep partnership with OpenAI to power most Copilot features at discounted rates. That arrangement is becoming less comfortable, and Mustafa Suleyman — the company’s AI chief — is building a Plan B.

Office on IT News

Microsoft is quietly replacing OpenAI with its own AI in Excel and Outlook