Shivon Zilis, former board member of OpenAI Inc., arrives at the federal court in Oakland, California, US, on Wednesday, May 6, 2026.
David Paul Morris | Bloomberg | Getty Images
The high-stakes trial in Elon Musk’s lawsuit against OpenAI CEO Sam Altman will conclude its second week of proceedings on Thursday.
Musk’s attorneys called several witnesses to the stand over the course of the week, including OpenAI President Greg Brockman and Shivon Zilis, who served on the startup’s board and has a close personal and professional relationship with Musk. A number of other executives, including Altman and Microsoft CEO Satya Nadella, could still be called to testify.
Zilis, who has four children with Musk, took the stand on Wednesday and was questioned by lawyers for Musk and OpenAI about the conversations she had about OpenAI’s corporate structure around 2017 and 2018.
Musk sued OpenAI, Altman and Brockman in 2024, alleging that they went back on their promises to keep the artificial intelligence company a nonprofit and to follow its charitable mission. He co-founded the startup alongside Altman and Brockman in 2015.
OpenAI established a for-profit subsidiary after Musk left the company in 2018, and that business unit is the central focus of his lawsuit.
During her testimony, Zilis said that her primary role at OpenAI was to serve as a liaison between Musk, Altman, Brockman and Ilya Sutskever, another co-founder at the company.
Zilis testified that the four executives discussed OpenAI’s corporate structure “ad nauseam,” including several different for-profit options. At one point during the negotiations, Zilis said Musk wanted OpenAI to join Tesla, and he offered Altman a board seat at the company.
“There were lots and lots of arguments about all of the different possible structures put in place at that time,” Zilis said.
Elon Musk stands in an elevator to attend the trial in his lawsuit over OpenAI for-profit conversion at a federal courthouse, in Oakland, California, U.S., April 30, 2026.
Manuel Orbegozo | Reuters
Musk, who testified earlier in the trial, said he wasn’t entirely opposed to OpenAI’s for-profit arm, but that it became “the tail wagging the dog.” He repeatedly accused Altman and Brockman of trying to “steal a charity.”
The Tesla CEO also debated creating AI lab within his electric vehicle company that would compete directly with OpenAI, but Zilis testified that it never materialized.
In 2023, Musk started a competing AI company, xAI, and merged it with his rocket company, SpaceX, earlier this year.
Zilis, who has worked across several of Musk’s companies, including OpenAI, Tesla and his brain tech startup Neuralink, said she began working with OpenAI as an informal advisor in 2016, which was how she met him.
She served on OpenAI’s board from 2020 to 2023, after Musk had already left the company. The pair had several children together during this period, though Zilis testified that Musk’s involvement was initially kept secret.
She said they had agreed on “complete confidentiality,” partly to protect the children from the security risk that can come from being associated with Musk. She said she eventually had to tell Altman that Musk was the father when she learned that his involvement was going to be revealed in the press.
OpenAI allowed Zilis to keep her board seat, and she said she ultimately resigned in 2023 when Musk decided to start xAI.
CNBC’s Lora Kolodny contributed to this story.
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