OpenAI says GPT 5.6 is the ‘preferred model’ for Microsoft Copilot amid breakup chatter

Earlier this week, Bloomberg reported that Microsoft was increasingly replacing OpenAI’s software with its own in-house models, known as MAI, in an effort to cut costs across apps like Word and Excel. The story reignited a persistent question about the two companies, which were once seen as inseparable partners: Were they drifting apart?

OpenAI responds with GPT 5.6 announcement

Now, OpenAI is attempting to put those breakup rumors to rest. During the launch of GPT 5.6 on Thursday, the company announced that the new model would become the “preferred model” powering Microsoft’s 365 Copilot. In a blog post, OpenAI stated that GPT 5.6 would support Microsoft users across the company’s suite of productivity apps, including Word, Excel, PowerPoint, and the newer Cowork tool.

“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 wrote.

What ‘preferred model’ actually means

The exact implications of being a “preferred model” remain somewhat unclear. The designation appears to confirm that OpenAI’s software will continue to power Microsoft’s apps, but it does not contradict Bloomberg’s earlier reporting that Microsoft is also relying more heavily on its own MAI models to reduce costs. The new disclosure does not negate that Microsoft has been shifting some workloads internally, nor does it specify the proportion of AI tasks handled by OpenAI versus Microsoft’s own models.

This ambiguity highlights the evolving nature of the partnership. While the two companies remain closely tied — Microsoft has invested billions in OpenAI — they are also increasingly competing in the same AI markets. Microsoft’s development of in-house models gives it more leverage and reduces dependency on a single provider.

Why this matters for users and the industry

For the millions of Microsoft 365 users, the announcement means that Copilot features will continue to be powered by OpenAI’s latest technology, at least for now. The “preferred model” status suggests that GPT 5.6 will be the default option, but Microsoft may still switch to MAI models for certain tasks or when cost savings are significant.

From an industry perspective, the situation reflects a broader trend: major tech companies are investing heavily in AI partnerships while simultaneously building their own capabilities. The OpenAI-Microsoft relationship remains one of the most important in the sector, but it is clearly becoming more complex and less exclusive.

Conclusion

OpenAI’s announcement of GPT 5.6 as the preferred model for Microsoft Copilot is a deliberate signal that the partnership remains strong, even as Microsoft develops its own AI alternatives. The move provides short-term clarity for users and investors, but the long-term trajectory of the relationship will depend on how both companies balance collaboration with growing competition. For now, GPT 5.6 will power Copilot, but the door remains open for Microsoft to rely more on its own technology in the future.

FAQs

Q1: Does this mean Microsoft will stop using its own MAI models?
A1: No. The announcement confirms GPT 5.6 as the preferred model for Copilot, but Microsoft has been increasingly using its own MAI models in apps like Word and Excel to cut costs. Both models are likely to coexist.

Q2: Will users notice any difference with GPT 5.6 in Copilot?
A2: Users may see improvements in response quality and capabilities, as GPT 5.6 is a newer and more advanced model. However, the core Copilot experience will remain similar.

Q3: Is the OpenAI-Microsoft partnership ending?
A3: No. While the relationship is evolving and Microsoft is building its own AI capabilities, both companies continue to emphasize their commitment to the partnership. GPT 5.6 being named the preferred model is a clear sign that the collaboration remains active.