OpenAI's new family of models will continue to power Microsoft's suite of workplace and productivity apps.

Earlier this week, Bloomberg reported that Microsoft was replacing some of OpenAI’s software with its own in-house models in an effort to cut costs. Those in-house models, known as MAI, were increasingly being used to power apps like Word and Excel, the outlet noted. The story raised an increasingly common question about the two companies, which were once seemingly inseparable, and have recently sent mixed signals about the status of their situationship: Were the two companies drifting apart? Now, OpenAI is attempting to put any insinuations of such a break to rest. During OpenAI’s launch of GPT 5.6 on Thursday, the company announced that it would become the “preferred model” powering Microsoft’s 365 Copilot. OpenAI noted in a blog post published Thursday that GPT 5.6 would support Microsoft users across the company’s suite of productivity apps, 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 wrote in a blog post. What being a “preferred model” actually means isn’t entirely clear, other than that OpenAI’s software will continue to power Microsoft’s apps. That said, it was never reported that ChatGPT’s software would stop powering Microsoft’s apps — merely that Microsoft was relying increasingly on its own software in an effort to reduce costs. The new “preferred model” disclosure doesn’t appear to negate that previous reporting. Last chance to save up to $190 on TechCrunch Founder Summit. Join 1,000+ founders and VCs at all stages for real-world scaling insights and connections that move the needle.Savings end June 26, 11:59 p.m. PT.