Details of the alleged deal could have considerable consequences for Microsoft, which currently has an agreement allowing it to access OpenAI's models until the end of the decade.

Danone said on Monday it has agreed to buy a majority stake in Kate Farms, a U.S. maker of plant-based organic drinks that will fit into the French food giant's specialized nutrition portfolio.

Once the best of friends, OpenAI and its most important financial backer Microsoft Corp. are now involved in tough negotiations over the future of their partnership.