Sam Altman, CEO of OpenAI, at the Hope Global Forums annual meeting in Atlanta on December 11, 2023.

Dustin Chambers | Bloomberg | Getty Images

OpenAI executives disputed Elon Musk’s claims laid out in a lawsuit Thursday, saying that Tesla The CEO is upset that he is no longer part of the AI ​​startup.

“We believe the claims in this lawsuit may stem from Elon’s regrets about not being involved in the company today,” OpenAI Chief Strategy Officer Jason Kwon wrote in an internal memo Friday that was reviewed by CNBC. “It is deeply disappointing to see Elon take this action against a company he helped create, especially given his close collaboration with some of you who are still here working for the mission.”

Musk co-founded OpenAI in 2015 and stepped down from the board in 2018, four years after saying AI was “potentially more dangerous than nuclear weapons.”

Now Musk is suing Microsoftbacked OpenAI and CEO Sam Altman, among others, claiming they had abandoned the company’s core mission of developing artificial intelligence “for the benefit of humanity as a whole.”

Since releasing the ChatGPT chatbot to the public in late 2022, OpenAI has become one of the hottest startups on the planet with a reported valuation of over $80 billion. The company’s complex “restricted profit” structure led to Altman being briefly removed from the board late last year, before an uproar among investors and employees led to his swift reinstatement.

Musk has long wanted recognition for his central role in the creation of OpenAI, and he spent large parts of the trial telling his version of events. His lawyers said in the lawsuit that Musk was approached in 2015 by Altman and OpenAI co-founder Greg Brockman and agreed to create a nonprofit lab to develop artificial general intelligence, or AGI, outside of the corporate realm.

Musk’s lawyers said their client contributed more than $15 million to OpenAI in 2016, “more than any other donor” and helped the startup build a team of “top talent.” The following year, Musk gave nearly $20 million to OpenAI, which lawyers reiterated was more than other backers. In total, Musk invested more than $44 million in OpenAI from 2016 through September 2020, according to the lawsuit.

In addition, Musk leased OpenAI’s initial office space “and paid the monthly rental costs,” the suit says. He was also “present for company milestones.”

Kwon didn’t dispute Musk’s central role in OpenAI’s early days, but added some other details. For example, Kwon writes that Musk at one point indicated he needed “full initial control and majority equity” and later proposed that OpenAI merge with Tesla.

“We didn’t think either approach was right for the mission,” Kwon wrote.

In the memo, Altman calls Musk his hero and says he misses the old version of his co-founder. But he said the company’s mission continues.

Although the dispute between the two parties first resulted in a bitter lawsuit, they have been at odds for some time.

Before parting ways with OpenAI, Tesla hired co-founder Andrei Karpati as its senior director of AI. Karpathy returned to OpenAI in 2023. And Musk has been particularly vocal in his opposition to OpenAI and its partnership with Microsoft in recent years, saying publicly in November that OpenAI has strayed from its original mission.

“OpenAI should be renamed ‘super closed source profit-maximizing AI,’ because that’s what it is,” Musk said on stage at The New York Times’ DealBook conference. Regarding OpenAI’s transformation from an “open source foundation” to a multibillion-dollar for-profit company, Musk said, “I don’t know, is that legal?”

Kwon insisted on Friday that OpenAI is independent and continues to work “to ensure that AGI benefits all of humanity.”

Musk’s lawyers did not immediately respond to a request for comment.

— CNBC’s Laura Kolodny and Hayden Field contributed to this report

WATCHING: Elon Musk’s lawsuit against OpenAI and Altman began a year ago