Microsoft Begins Replacing OpenAI and Anthropic With Its Own MAI Models in Excel and Outlook

Microsoft has begun replacing OpenAI and Anthropic models with its own in some of its office products, including Excel and Outlook. According to a Bloomberg report, tens of thousands of AI queries in these apps are now being handled every week by internally built models from the MAI family.

Scale of the Change

For now, the shift to in-house models covers only a small slice of the overall AI traffic generated by Microsoft's products, but the company is signaling that the scale will grow. Excel and Outlook, two of the most widely used office applications in the world, have become the first testing ground for MAI models in the daily work of millions of users.

Microsoft also confirmed plans to roll out its own transcription models in Microsoft Teams, marking another area where the company is moving away from external providers in favor of solutions built in-house.

Cost Motivation

The main reason behind the change is cost. Mustafa Suleyman, Microsoft's head of AI, spoke openly about this in June, pointing to the high fees the company pays Anthropic for access to the Claude models used in its products.

We pay Anthropic a ton of money, so our goal is to reduce, and eventually eliminate, that cost - Mustafa Suleyman, Microsoft's head of AI

Microsoft still benefits from privileged access to OpenAI's models thanks to the two companies' long-standing partnership, but that agreement itself has time limits. Building its own MAI models is meant to protect Microsoft from future pricing dependence on partners it also competes with in the market for business AI tools.

Competitiveness of the New Models

At the June Build conference, Microsoft showed off seven new models, including one designed for coding tasks that the company says achieves results close to Anthropic's Opus 4.6, but at a significantly lower computational cost. That puts it in direct competition with the models Microsoft itself offers to customers using GitHub Copilot.

The decision fits a broader industry trend in which major cloud and software providers are trying to reduce their reliance on outside AI labs by building their own models that are good enough for everyday office tasks, even if they don't match competitors' top flagship models.

What This Means for Companies in Poland

For businesses using Microsoft 365 and Copilot, the change may not be noticeable at first glance, since the interface stays the same and the model running behind the scenes depends on the task it has been assigned. In practice, though, this could mean gradual shifts in response quality for certain Excel and Outlook features as Microsoft moves more queries onto its own models.

For Polish companies paying for Copilot licenses, what may matter more is whether cheaper in-house models allow Microsoft to lower subscription prices down the line, since one of the main arguments for the change is cutting the cost of external contracts. So far, the company has not announced any pricing changes tied to this shift.

Sources: Microsoft Replaces OpenAI, Anthropic With Own AI in Some Apps (bloomberg.com), Microsoft Replaces OpenAI, Anthropic With Own AI in Some Apps (finance.yahoo.com), Copilot goes cheap as Microsoft phases out OpenAI and Anthropic models to cut costs (the-decoder.com)