Microsoft Transitions Word And Excel AI Prompts To In-House MAI, Cutting OpenAI And Anthropic Use

Microsoft has started transitioning away from OpenAI and Anthropic AI models by applying its in-house MAI model to some AI responses in Word and Excel, with TechCrunch reporting the change as a cost-cutting move that increases use of Microsoft’s own models.

Bloomberg reported that Microsoft is routing some Excel and Outlook AI prompts to its own MAI models, and the in-house system is handling tens of thousands of AI prompts per week in those apps.

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The shift is not a full replacement, because Microsoft continues to use OpenAI and Anthropic models while also expanding efforts to build its own AI agents.

At Microsoft’s annual Build developer event, the company unveiled 7 new MAI models, including its first-ever flagship reasoning model, and the reporting ties the rollout to MAI-Image-2.5 being used by PowerPoint.

Microsoft AI CEO Mustafa Suleyman has said the team’s goal is eliminating reliance on outside models, including that an MAI transcription model, MAI-Transcribe-1.5, would soon be used by Microsoft Teams.

TechCrunch said Microsoft is lowering its reliance on OpenAI and Anthropic in part to cut costs and is increasing use of its own models, while DigitalToday reported that Microsoft has arranged for its in-house MAI model to respond to a certain share of user prompts.

The reporting frames the change as a workload-level routing decision rather than a complete partner break, with Bloomberg saying tens of thousands of weekly prompts in Excel and Outlook are being completed with internally built MAI models.

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The Decoder’s account, citing Bloomberg, says Microsoft is replacing AI models from OpenAI and Anthropic with its own in-house models across several Copilot products, including Excel and Outlook, and that the MAI models are already processing tens of thousands of requests per week.

In the same reporting, Microsoft declined to comment to MT Newswires, and PYMNTS reported that when reached by PYMNTS, Microsoft declined to comment on the report.

Mustafa Suleyman’s stated aim is to reduce and ultimately eliminate spending on Anthropic, and The Decoder quotes him: "We pay a lot of money to Anthropic—so our goal is to reduce and ultimately eliminate that cost."

Beyond Excel and Outlook, the reporting says MAI is also used with GitHub Copilot, and that Microsoft plans to deploy its proprietary speech-to-text model in products like Teams.

Thurrott reported that MAI models are used with GitHub Copilot and that Mustafa Suleyman said MAI-Transcribe-1.5 would soon be used by Microsoft Teams, while The Decoder adds that a proprietary transcription model is expected to ship in Teams soon.

In parallel, DigitalToday said Microsoft continues to use OpenAI and Anthropic models while expanding efforts to build its own AI agents, and it described the Build rollout as including an agentic coder and a text-to-image generator.

Incrypted’s Build 2026 breakdown describes MAI as a family of seven new models across image generation, speech synthesis, audio transcription, reasoning, and code writing, and it says the flagship reasoning model is MAI-Thinking-1.

Incrypted also reports that MAI-Transcribe-1.5 is integrated into Copilot and Teams, and it states that the model runs up to five times faster than competing models on the company’s claims.