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.
Text messages and e-mails between Zilis and Musk produced as evidence showed that Musk, while still on the board of OpenAI, was working to poach top talent from the company’s ranks, which contradicted his earlier claims.
He also stopped making regulator donations as OpenAI considered starting a for-profit arm. In August 2017 communications between Zilis and another Musk employee, Sam Teller, Zilis referenced a “funding freeze,” though he hadn’t informed his co-founders of the decision.
Zilis wrote that “OpenAI is likely to realize this week” that $5 million in funding for the quarter was on hold, and will “likely to have a big psychological impact on them if they find out.”
In February 2018, as it became clear that OpenAI would not join Tesla, Zilis messaged Musk to ask if he wanted her to remain close with the team there or take some distance.
“Close and friendly but we are going to actively try to move three or four people from OpenAI to Tesla,” he replied. “More than that will join over time but we won’t actively recruit them.”
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 Andrej Karpathy, who left OpenAI to lead Tesla’s Autopilot efforts, was already going to leave the nonprofit, and that Musk wasn’t actively luring people to join Tesla.
After an OpenAI lawyer showed Zilis text messages with her celebrating Musk’s offer to Karpathy and his acceptance of it, Zilis conceded that Musk approached Karpathy first.
Musk said in his testimony that 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.”
Zilis emails showed that Musk considered creating an AI lab within Tesla that would compete directly with OpenAI, and potentially Google’s DeepMind. But Zilis testified that such a lab never materialized.
Instead, Musk started a competing AI venture, xAI, in 2023. He merged that business with SpaceX earlier this year. Musk said Wednesday that xAI is now known as SpacexAI.
Zilis wrote in a text message to a friend on Feb. 25, 2023, as word was getting out that Musk was starting a competitor to OpenAI, “When the father of your babies starts a competitive effort and will recruit out of OpenAI there is nothing to be done.”
Zilis worked across several of Musk’s companies, including OpenAI, Tesla and brain tech startup Neuralink. She said she began working with OpenAI as an informal advisor in 2016, which was how she met Musk.
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.
Zilis said she signed a non-disclosure agreement with Musk about his “donation,” and agreed on “complete confidentiality,” partly to protect the children from the security risk that can come from being associated with Musk, but also because he wasn’t initially planning to be an active father to her children.
She testified that Musk is actively involved today and that they live together when he’s spending “family time” in Austin, Texas, and sometimes during travels.
Zilis said she eventually had to tell Altman that Musk was the father of her kids when she learned that the press was pursuing the story.
OpenAI allowed Zilis to keep her board seat despite the personal entanglements but she said she ultimately resigned in 2023 as chatter was spreading about Musk starting a competitor.
WATCH: Musk v. Altman heads to trial: Here’s what you need to know
