Week 3 of the billion-dollar lawsuit trial between Elon Musk and Sam Altman, two of Silicon Valley’s most powerful men, got off to an important start as high-profile witnesses such as Microsoft CEO Satya Nadella and Ilya Sutskever, a former OpenAI co-founder and renowned AI researcher, took the stand on Monday, May 11.
First, Nadella was subjected to several hours of questioning and gave answers pertaining to the early days of Microsoft’s partnership with OpenAI, the relationship between the two tech companies, and his role during the chaotic few days after Altman was briefly ousted as CEO of OpenAI in 2023.
Alongside OpenAI, Sam Altman, and OpenAI president Greg Brockman, Microsoft is named as a defendant in Musk’s 2024 lawsuit alleging that OpenAI’s leadership went back on their vow to protect the AI company’s nonprofit structure and follow its charitable mission. In his lawsuit, Musk has accused Microsoft of aiding and abetting OpenAI’s purported breach of charitable trust.
The lawsuit trial, which began on April 28, in a US federal courthouse in Oakland, California, has billions of dollars and the future of the AI industry at stake. After Nadella’s testimony, Sutskever took the stand to answer questions about his decision to join OpenAI, his communications with Musk, and his involvement in Altman’s 2023 ouster.
Here is a brief summary of both testimonies.
Key moments from Satya Nadella’s testimony
-OpenAI’s for-profit arm: When asked whether OpenAI’s for-profit subsidiary breached its nonprofit mission, Nadella said: “The nonprofit approved the creation of the for-profit entity, so they could continue to pursue the mission.” “If the pie became larger, the nonprofit would benefit as well,” he added.
-Musk’s concerns: Nadella testified that Musk never contacted him with concerns that Microsoft’s investments in OpenAI were in violation of any special terms or commitments. He also said that they have each other’s phone numbers.
-Backing OpenAI: For context, Microsoft has been OpenAI’s largest investor since 2019, years before the launch of ChatGPT which thrust the company into the mainstream. It has invested more than $13 billion in OpenAI over the years: $1 billion investment in 2019, $2 billion in 2021, and $10 billion in 2023.
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– In his testimony last month, Musk said that the scale of Microsoft’s $10 billion investment in OpenAI in 2023 was the tipping point that made him believe OpenAI was violating its nonprofit mission.“I was concerned they were really trying to steal the charity,” Musk said
-On Monday, Nadella said, “I’m very proud of the fact that we took the risk when no one else was willing to sponsor this fledgling lab” and “start all the innovation that the industry has today.”
-He also said that he did not believe Microsoft’s investments in OpenAI were donations, and that there was a clear commercial element to their partnership from the outset. Microsoft gave OpenAI sharp discounts on computing resources, and Microsoft believed it would reap marketing benefits from doing so.
-Altman’s ouster: For context, Altman was briefly fired in November 2023 from his role as OpenAI CEO after the board determined he had not been “not consistently candid in his communications.” He was reinstated days later, after an intense few days of negotiations.
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-On Monday, Nadella testified that he was “pretty surprised” by the board’s decision to fire Altman, and that his priority was to try and figure out how to maintain continuity for Microsoft customers.
-That language “just didn’t sort of suffice, because this is the CEO of a company that we are invested in and we’re deeply partnered with, and so I felt that they could have explained to me what are the incidents or what is the detail behind it,” he said.
-There must have been instances of jealousy or miscommunication that could have justified pushing out Altman, he said. He was also “very worried that the employees were going to leave en masse.”
-After Altman’s firing, Nadella said he had talks with OpenAI board members to try to understand the language in the OpenAI’s statement about Altman being “not consistently candid” while communicating with the board. “It was sort of amateur city, as far as I’m concerned,” Nadella testified.
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-Nadella also said that he never demanded OpenAI to reinstate Altman as CEO. This is contrary to the testimony provided by former OpenAI board member Tasha McCauley, who said, “To the best of my recollection, Satya wanted to restore things to as they had been. The board members didn’t think that was the right move.”
Key moments from Ilya Sutskever’s testimony
Sutskever is a central figure in OpenAI’s fight against Musk as he played a key role in Altman’s dramatic firing and rehiring in 2023. He was one of the employees who had expressed concerns about Altman’s behaviour to the board, in part because he said he felt “a great deal of ownership” over the startup.
Ilya Sutskever, co-founder and former chief scientist at OpenAI, arrives for a hearing in Elon Musk’s lawsuit against OpenAI at the Ronald V. Dellums federal courthouse in Oakland, Calif., on Monday, May 11, 2026. (Jason Henry/The New York Times)
However, Sutskever later expressed regret over his participation in the board’s actions and voted to reinstate Altman over fears that OpenAI would collapse. “I simply cared for it, and I didn’t want it to be destroyed,” Sutskever said on Monday. He left OpenAI in 2024 and has since launched an AI startup called Safe Superintelligence.
-Google offer: Sutskever, who used to work at Google, testified that the company offered to pay him as much as $6 million a year to try and keep him from leaving for OpenAI.
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-Altman’s removal: Sutskever testified on Monday that he spent about a year gathering evidence at the request of OpenAI’s board that Altman had displayed a “consistent pattern of lying.” He said that Altman’s conduct included “undermining and pitting executives against one another.” The document gathered by Sutskever on Altman’s alleged dishonesty is reportedly 52 pages-long.
Sutskever further said that he had discussed removing Altman with then chief technology officer Mira Murati after the two discussed Altman’s behavior “for a long time.” The weekend after the board voted to fire Altman, Sutskever said that he avoided the internet and was not initially aware of contingency plans like Microsoft’s proposal to absorb Altman, Brockman, and other OpenAI employees into a new subsidiary.
-OpenAI stake: Sutskever disclosed on Monday that his ownership stake in OpenAI was worth about $5 billion as of November 2025, and about $7 billion currently.
-Anthropic talks: He also confirmed that after Altman’s brief ouster, the remaining OpenAI board members met with rival Anthropic about a proposal for the Claude chatbot creator to merge with OpenAI and take over its leadership. He said he was “not excited” about merging OpenAI with another company.
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What next?
Altman’s testimony is slated to begin on Tuesday, according to his lawyers, with closing arguments for the trial likely on Thursday, May 14, according to US District Judge Yvonne Gonzalez Rogers. Former and current OpenAI executives, including Brockman, Murati and Shivon Zilis, have already testified in the trial.
