OpenAI and Microsoft may be breaking up, potentially leaving Microsoft’s Copilot without a, uh, copilot, according to a new report by the Wall Street Journal.

The two tech giants have been in a symbiotic relationship for six years, with Microsoft tapping OpenAI’s generative AI technology to power its AI assistant, Copilot, in Windows 11 and Bing.

But amid negotiations to separate the partners-turned-competitors, OpenAI execs have begun discussing whether to accuse Microsoft of anticompetitive behavior during their partnership, the Wall Street Journal reported, citing people familiar with the matter. (Disclosure: Ziff Davis, CNET’s parent company, in April filed a lawsuit against OpenAI, alleging it infringed Ziff Davis copyrights in training and operating its AI systems.) A sudden breakup could make teasing out their integration a bit messy.

Microsoft announced in May that its AI assistant, Copilot, would begin using GPT-4o, OpenAI technology that also powers the paid version of ChatGPT. Copilot was launched in 2023 to add AI across Microsoft’s platforms.

Representatives for Microsoft and OpenAI didn’t immediately respond to requests for comment.