Elon Musk never once complained to Satya Nadella about Microsoft's deepening ties with OpenAI, the Microsoft CEO testified Monday, undercutting a core claim in Musk's lawsuit before the trial entered its final stretch.
Nadella spent several hours on the stand in Oakland federal court answering questions about Microsoft's $13 billion-plus investment in OpenAI, the 2023 ouster of Sam Altman, and Musk's evolving stance on the partnership. Musk sued OpenAI, Altman, and Microsoft in 2024, alleging the companies betrayed OpenAI's nonprofit mission by turning it into a for-profit machine. The problem for Musk: he publicly welcomed Microsoft's help years earlier.
Nadella showed jurors a 2017 email in which Musk thanked him for Microsoft's financial and computing support. An OpenAI bot had just defeated a pro player at the Dota 2 world championship, and Nadella had congratulated the team.
Musk replied: "Very much appreciated. Will make sure that people know about Microsoft's help."
Microsoft took a $15 million loss by giving OpenAI discounted Azure cloud access to power early ChatGPT development, Nadella testified.
Musk never raised concerns when the revenue-sharing partnership was announced in July 2019, nor when Microsoft's investment jumped by $10 billion in 2023. "We have each other's phone numbers," Nadella told jurors, making clear Musk had direct access to him.
Musk testified late last month that the $10 billion investment was the tipping point that convinced him OpenAI was violating its nonprofit mission. "I was concerned they were really trying to steal the charity," Musk said from the stand.
Nadella said he did not view Microsoft's investments as donations. The partnership had a clear commercial element from the start, he said, with Microsoft expecting marketing benefits and deep discounts on computing resources in return. The testimony also covered Altman's brief firing in November 2023. Nadella called the board's decision to remove Altman "amateur city," saying board members could not explain why they took such a drastic step.
"There must have been some jealousies or communications," Nadella said. He was "pretty surprised" by the firing and focused on maintaining continuity for Microsoft customers.
Former OpenAI director Tasha McCauley said in a deposition that Nadella "wanted to restore things to as they had been" after the firing. But Nadella testified he never demanded the board reinstate Altman.
Musk's lawyers pressed Nadella on his 2023 comment that Microsoft was "below them, above them, around them" regarding OpenAI. Nadella said he was reassuring customers during the crisis.
"It goes back to me trying to communicate as clearly as possible to customers that they can count on us," he said. "It had nothing to do with control."
Michael Wetter, a Microsoft corporate development executive, said in a video deposition that the company has recognized roughly $9.5 billion in revenue through its OpenAI partnership as of March 2025. Microsoft holds a 27% stake in OpenAI's for-profit unit, valued at around $135 billion.
After Nadella stepped down, OpenAI co-founder Ilya Sutskever testified that his stake in the for-profit arm is worth about $7 billion. OpenAI board chairman Bret Taylor followed and will continue his testimony Tuesday.
Evidence is scheduled to wrap up Wednesday, with closing statements to the nine-member jury expected Thursday.
