OpenAI stated on Thursday that its latest model, GPT-5.6, will serve as the preferred AI system powering Microsoft's 365 Copilot. The announcement came during the launch of the new model and appears to be a direct response to recent speculation about a possible rift between the two companies.
Background: Reports of a Drift
Earlier this week, Bloomberg reported that Microsoft had begun replacing some of OpenAI's software with its own internal models, called MAI, in an effort to reduce costs. According to the report, Microsoft was increasingly using MAI to power applications such as Word and Excel, raising questions about the future of the partnership.
The story added to a growing narrative that the two companies, once seen as inseparable, have recently sent mixed signals about the status of their relationship. Many observers wondered whether the pair were drifting apart.
OpenAI's Response
During the GPT-5.6 launch event on Thursday, OpenAI pushed back against any notion of a breakup. In a blog post, the company wrote that GPT-5.6 would support Microsoft users across its productivity suite, including Word, Excel, PowerPoint, and Cowork.
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"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.
What 'Preferred Model' Means
What exactly being a 'preferred model' entails remains somewhat ambiguous. The designation suggests that OpenAI's software will continue to power Microsoft's applications, but it does not clarify whether Microsoft will still use its own MAI models alongside GPT-5.6.
The earlier Bloomberg report never claimed that ChatGPT's software would stop powering Microsoft's apps entirely. It simply noted that Microsoft was relying increasingly on its own technology to lower expenses. OpenAI's new disclosure does not contradict that reporting.
The situation highlights the evolving dynamics between the two tech giants, which have long been closely tied. While rumors of a split have circulated, OpenAI's latest move attempts to reaffirm the partnership's strength, even as Microsoft pursues its own AI development.

