OpenAI co-founder Ilya Sutskever and Microsoft CEO Satya Nadella have taken the witness stand in Elon Musk's lawsuit against the artificial intelligence research organization. The two billionaires were among the high-profile figures called to testify in the trial, according to court proceedings reported from the courtroom.

The lawsuit, filed by Musk against OpenAI, marks a dramatic turn in the relationship between the billionaire entrepreneur and the company he helped found. Musk left OpenAI's board in 2018 and has since raised public concerns about the organization's transition from a nonprofit to a for-profit model and its deepening partnership with Microsoft. The trial has drawn intense interest from the tech industry, as it touches on fundamental questions about the governance and mission of one of the world's most prominent AI labs.

Ilya Sutskever, a co-founder of OpenAI and its former chief scientist, is a central figure in the company's technical achievements. He previously worked at Google Brain and was a key contributor to the development of large language models that underpin products like ChatGPT. Sutskever's testimony is likely to carry substantial weight, given his insider perspective on the company's strategic decisions over the years. He left OpenAI in 2024 after the board's brief attempt to oust CEO Sam Altman, but his knowledge of internal debates around safety and commercialization remains unmatched. The source briefing confirms that Sutskever testified as part of the trial.

Satya Nadella, Microsoft's CEO since 2014, represents the other major corporate player in the story. Microsoft has invested billions of dollars into OpenAI and tightly integrated the startup's models into its Azure cloud platform and office productivity tools. Nadella's testimony sheds light on the nature of the partnership between the two companies, which Musk's lawsuit claims has strayed from OpenAI's original nonprofit mission. As the head of one of the world's largest technology companies, Nadella's appearance underscores how high the stakes are for both the industry and the legal interpretation of what OpenAI owes its original founders.

The trial itself stems from Musk's allegations that OpenAI has abandoned its founding charter to develop artificial general intelligence (AGI) for the benefit of all humanity. Musk contends that the company's exclusive licensing deal with Microsoft and its shift toward profit-making entities violate the original nonprofit agreement. OpenAI has denied these claims, arguing that the partnership with Microsoft provides necessary funding and computing resources to fulfill its mission safely. The testimony from Sutskever and Nadella is expected to provide direct evidence on the internal discussions that shaped OpenAI's transformation.

Neither Sutskever nor Nadella has made public statements about their testimony since taking the stand. The trial is ongoing, and the court has not yet released transcripts or full summaries of their remarks. The limited information available highlights the secrecy surrounding high-stakes corporate litigation, where much of the detailed testimony remains under seal. Nonetheless, the mere fact that both men were called to testify signals that the court considers their firsthand accounts critical to resolving the dispute.

The case has become a flashpoint for broader debates about the control of generative AI technology. Musk has positioned himself as a critic of closed, centralized AI development, while OpenAI and Microsoft argue that their approach balances innovation with safety. The outcome of the trial could set precedents for how courts interpret the obligations of technology companies that start as nonprofits and later adopt for-profit structures.

For now, the testimony of Sutskever and Nadella provides a rare window into the private deliberations that have shaped one of the most consequential business relationships in technology. Their appearances also highlight the personal and financial ties that bind the key players: Musk, Sutskever, and Nadella are all billionaires with competing visions for AI's future. As the trial continues, the public will learn more about what was said in the boardrooms and emails of both OpenAI and Microsoft.

The source briefing confirms that Sutskever and Nadella are among the billionaires who have testified in this trial. No further details about the content of their testimony have emerged from the court. The lawsuit is expected to run for several more weeks, with additional witnesses likely to include current and former OpenAI executives, Microsoft board members, and outside experts on artificial intelligence. The industry is watching closely.