GPT-5.6 becomes preferred AI model in Microsoft 365 Copilot

OpenAI announced on Thursday that its GPT-5.6 family of models is now the preferred model powering Microsoft ↘ 0.99% 365 Copilot, available across Word, Excel, PowerPoint, and Teams Chat. The rollout coincides with GPT-5.6's broader public release after a two-week period of limited access at the request of the U.S. government.cnbc+2

What GPT-5.6 Brings to Copilot

According to OpenAI, GPT-5.6 represents a step forward in artifact generation within Microsoft 365. In Word, the model can help users draft and refine documents with fewer rounds of prompting, while in Excel it supports deeper data analysis. The update follows GPT-5.2, which had powered Copilot for Microsoft 365 since December 2025.openai+2

Microsoft's documentation indicates that enterprise administrators can enable OpenAI-operated models starting immediately, with automatic enablement for eligible commercial customers set for July 24, 2026. Organizations that prefer not to use OpenAI-operated models can opt out through the Microsoft 365 admin center.learn.microsoft

Microsoft's Quiet Bet on In-House AI

The announcement arrives against the backdrop of Microsoft's growing investment in its own AI capabilities. Bloomberg reported last week that Microsoft has begun replacing OpenAI and Anthropic models with its internally built MAI models in products like Excel and Outlook, with tens of thousands of prompts weekly now handled by MAI. The company unveiled seven MAI models at its Build conference in June, spanning reasoning, coding, image generation, voice, and transcription.thenextweb+2

Microsoft has been testing MAI-Transcribe-1 in Teams and rolling MAI-Image-2 into Bing and PowerPoint. The shift, enabled by the 2025 renegotiation of the companies' partnership that freed Microsoft to build competing models, is described as incremental — OpenAI and Anthropic still handle most production traffic inside Copilot.thenextweb

A Partnership Under Pressure

The dual moves — elevating GPT-5.6 to preferred status while simultaneously deploying rival in-house models — illustrate the evolving tension in one of tech's most consequential partnerships. Microsoft is reducing costs and dependency where economics favor it, while OpenAI secures its position atop the most visible enterprise AI product in the world. As The Next Web noted, Microsoft is "steadily reducing a dependence it spent years and billions building".thenextweb