Microsoft shifts Excel, Outlook AI in-house
Microsoft is moving some Copilot prompts in Excel and Outlook from OpenAI and Anthropic to its own MAI models to cut costs, Bloomberg reports.
Microsoft is incrementally shifting some AI prompts inside Excel and Outlook away from OpenAI and Anthropic models and toward its own in-house MAI family, Bloomberg reported on July 7, citing people familiar with the plan. The move is aimed squarely at cost: Microsoft AI chief Mustafa Suleyman said the company wants to “reduce and ultimately eliminate” what it spends on Anthropic specifically.
OpenAI and Anthropic still handle the bulk of Copilot traffic today, this is described as an incremental, app-by-app shift rather than a wholesale cutover. Microsoft unveiled seven new MAI models at its June Build conference, and the company claims at least one of them matches Claude Opus 4.6’s coding ability at lower cost, though that comparison hasn’t been independently verified.
The timing lines up with a broader cost-cutting push at Microsoft: the company cut about 4,800 jobs the same week, roughly 2.1% of its workforce, with reporting tying the cuts to AI infrastructure spending pressure after Microsoft committed roughly $190 billion in AI capital expenditure for 2026 (see our coverage of the layoffs).
For any product built on Microsoft’s Copilot APIs, the practical implication is that the model doing the work behind a given feature may quietly change over time, worth watching for behavior shifts in outputs even when your integration code hasn’t changed.