Microsoft Quietly Swaps OpenAI and Anthropic for Its Own MAI in Excel and Outlook
Summary: Microsoft is gradually pulling OpenAI and Anthropic models from routine Office app tasks and replacing them with its own MAI models — a shift with large financial and strategic implications.
Key Facts
- Tens of thousands of Excel and Outlook AI prompts are now handled by MAI models weekly, per Bloomberg's July 7 report
- Microsoft's MAI family (launched at Build 2026) spans seven models: reasoning, coding, image generation, speech, and transcription
- A McKinsey-tuned MAI model beat GPT-5.5 on cost efficiency by a factor of ten
- Mustafa Suleyman, Microsoft's AI chief: "We pay a lot of money to Anthropic — our goal is to reduce and ultimately eliminate that cost"
- OpenAI's frontier models still handle complex tasks; the shift is incremental, not a full break
Why It Matters
Microsoft invested tens of billions in OpenAI but has steadily renegotiated terms that let it build competing models. If MAI handles the long tail of routine Copilot prompts while OpenAI covers high-complexity tasks, Microsoft could dramatically reduce its per-query cost — and the financial exposure that underpins OpenAI's partnership valuation. This is the clearest public signal yet that vertical AI integration, not outsourcing, is Microsoft's long-term play.
Read More
- Microsoft Replaces OpenAI, Anthropic With Own AI in Some Apps — Bloomberg
- Microsoft replaces OpenAI, Anthropic models in Excel, Outlook — American Bazaar Online