Just days after reports suggested their pivotal partnership was on the rocks, OpenAI has named its new GPT-5.6 the "preferred model" for Microsoft 365 Copilot—a clear attempt to calm nervous investors and customers.

"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.

Why This Matters Now

The announcement is a clear shot across the bow at a Bloomberg report from earlier this week. That report claimed Microsoft was quietly swapping out OpenAI's tech for its own in-house models, dubbed MAI, to cut costs in apps like Word and Excel.

That news fueled growing "breakup chatter" and raised serious questions about the long-term stability of tech's most important alliance. For months, the two companies have sent mixed signals about the true nature of their relationship.

Unpacking "Preferred Model"

While the term "preferred model" strongly reinforces OpenAI's central role in Microsoft's flagship AI product, its exact meaning is intentionally vague. The announcement certainly doesn't kill the reports that Microsoft is building and using its own models.

Ultimately, the move serves to publicly reaffirm the partnership's value, assuring everyone that the core collaboration is secure—even as Microsoft builds its own AI arsenal in parallel.