Microsoft 365 favors company models

Microsoft is starting to favor its own AI models inside Microsoft 365 workflows, especially in products such as Excel and Outlook, according to reports published July 8 and July 9. The shift does not mean OpenAI’s ChatGPT or Anthropic’s Claude disappear from Microsoft’s stack. It means Microsoft is increasingly deciding that the default path inside core office software should run through Microsoft-built models first, while outside models remain available in selected products, regions or settings. (msn.com) That matters because Microsoft controls one of the biggest work surfaces in enterprise software. (learn.microsoft.com) If the company changes which model handles document drafting, spreadsheet analysis or email assistance by default, that affects not only model vendors but also startups that assumed Microsoft would stay neutral about which AI sits inside those tasks. ### Where is Microsoft making the change first? Bloomberg, as cited by Yahoo Finance on July 8, reported that Microsoft is replacing OpenAI and Anthropic models with its own in some products including Excel and Outlook. PCMag reported the same day that Microsoft 365 apps were favoring Microsoft’s own models over ChatGPT and Claude. (uk.pcmag.com) The reports describe a production shift inside Microsoft 365 Copilot rather than a public break with outside model providers. Microsoft has continued to publish documentation and blog posts showing Anthropic models available in parts of Copilot Studio, Microsoft 365 Copilot and related services. (uk.pcmag.com) ### Why is Microsoft doing this now? Mustafa Suleyman, Microsoft’s AI chief, said at Build that the company’s goal is to “reduce and ultimately eliminate” spending on external AI models, according to PCMag and The Next Web. The Next Web also reported Suleyman called Anthropic “extremely expensive.” (finance.yahoo.com) That cost focus fits Microsoft’s broader effort to push its own MAI family of models into customer-facing products. Microsoft introduced seven in-house MAI models at Build, according to The Next Web, giving the company a cheaper internal option for high-volume office tasks where inference costs can add up quickly. (microsoft.com) ### Does this mean Microsoft is abandoning OpenAI and Anthropic? Microsoft’s own documentation says no. Microsoft Learn pages published in 2026 say Anthropic models are enabled by default for most commercial-cloud customers in some Microsoft online services, and that Microsoft 365 Copilot includes an admin setting enabling Anthropic models in Word, Excel and PowerPoint for customers in the European Union, European Free Trade Association and United Kingdom. (msn.com) Microsoft also published a June post saying Claude Opus 4.8 was rolling out in Microsoft 365 Copilot experiences including Excel and PowerPoint for some users. (thenextweb.com) That shows the company is still presenting model choice where it thinks customers want it, even as it shifts more baseline traffic to its own systems. ### What changes for startups building on top of Microsoft workflows? Microsoft’s position gives it control over routing, pricing, evaluation and product defaults inside Office. Directions on Microsoft wrote earlier this year that adding Anthropic answered customer demand for options and helped avoid model lock-in, but also carried governance and product trade-offs. (learn.microsoft.com) If Microsoft now prefers its own models in the highest-volume workflows, startups depending on equal treatment for outside models face a different distribution environment. That does not remove opportunities around Microsoft 365. (techcommunity.microsoft.com) It does mean companies building agents, integrations or workflow products inside Microsoft’s surface have to assume Microsoft can change the default model path, the admin controls and the economics of access. Microsoft’s next public product updates are likely to appear through Microsoft 365 Copilot blog posts, Learn documentation and Copilot Studio announcements, where the company has been publishing model-availability changes through 2026. (techcommunity.microsoft.com) (directionsonmicrosoft.com)