Bloomberg: Microsoft is replacing OpenAI and Anthropic models inside Excel and Outlook to cut Copilot costs.

Excel and Outlook used to lean more heavily on outside models. Now Microsoft wants fewer expensive calls to labs that control pricing for frontier model access.

OpenAI still gives Microsoft favorable access through their long partnership, but that discount may fade.

Microsoft AI head Mustafa Suleyman has been clear that Microsoft wants to reduce, then remove, that outside cost.

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bloomberg .com/news/articles/2026-07-07/microsoft-replaces-openai-anthropic-with-own-ai-in-some-apps