Earlier this week, a Bloomberg report indicated that Microsoft was in the process of replacing some of OpenAI's software with its proprietary in-house models, primarily as a cost-saving measure. These internal models, designated as MAI, were reportedly seeing increased deployment across core applications such as Word and Excel.
This development reignited a persistent question surrounding the two companies, once perceived as inextricably linked, yet recently signaling a more complex relationship: was their partnership beginning to diverge?
OpenAI has now moved to dispel any notions of such a separation. During the launch event for GPT 5.6 on Thursday, the company declared that its new model would become the "preferred model" for Microsoft's 365 Copilot suite.
In a blog post published concurrently on Thursday, OpenAI further elaborated that GPT 5.6 is set to provide support for Microsoft users across its full array of productivity applications, including Word, Excel, PowerPoint, and Cowork.
"Our partnership with Microsoft has always been about bringing the benefits of advanced AI to more individuals and organizations, and we’re excited to continue building on that shared commitment," OpenAI stated in its blog post.
The precise implications of being a "preferred model" remain somewhat ambiguous, beyond the clear indication that OpenAI's software will continue to power Microsoft's applications.
It is important to note that prior reports never suggested a complete cessation of ChatGPT's software powering Microsoft's apps; rather, they highlighted Microsoft's increasing reliance on its own internal software to mitigate costs. This new disclosure regarding GPT 5.6 as the "preferred model" does not appear to contradict that earlier reporting.
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