Adds Musk closing argument throughout

By Deepa Seetharaman and Jonathan Stempel

OAKLAND, California, May 14 (Reuters) - A lawyer for Elon Musk hammered at the credibility of OpenAI CEO Sam Altman on Thursday, near the end of a trial over whether to hold the ChatGPT maker and its leaders responsible for transforming the nonprofit into a vehicle to enrich themselves.

Musk is suing OpenAI and Altman for breach of charitable trust and unjust enrichment, accusing them of "stealing a charity" by straying from OpenAI's founding mission to build safe artificial intelligence to benefit humanity.

The world's richest person said the OpenAI defendants manipulated him into giving $38 million, then went behind his back by attaching a for-profit business to its original nonprofit, and accepting tens of billions of dollars from Microsoft MSFT.O and other investors to grow.

Musk is seeking about $150 billion in damages from OpenAI and Microsoft, which would be paid to OpenAI's nonprofit to further its altruistic goals. He also wants Altman and OpenAI President Greg Brockman removed from their roles.

OpenAI has said the organization is stronger as a for-profit entity, including the nonprofit that is now a shareholder of the corporation, and that Musk simply wanted unilateral control in exchange for continued support.

MUSK LAWYER CRITICIZES 'ARROGANCE'

In his closing argument in the Oakland, California, federal court, Musk's lawyer Steven Molo told jurors that five witnesses including Musk, former OpenAI board members and former OpenAI Chief Scientist Ilya Sutskever, testified that Altman was a liar.

Molo also noted that during cross-examination on Tuesday, Altman did not say yes unequivocally when asked if he was completely trustworthy and did not mislead people in business.

"Sam Altman's credibility is directly at issue in this case," Molo said. "If you don't believe him, they cannot win."

Molo challenged Brockman's goals for the business, citing Brockman's statement that his own OpenAI stake was worth nearly $30 billion.

"The arrogance, the lack of sensitivity, the failure to account for just common decency is really, really abhorrent."

Molo accused the OpenAI defendants of breaching the charitable trust Musk created by enriching investors and insiders at the nonprofit's expense, and failing to prioritize AI safety, open-source technology, and follow good nonprofit governance.

The lawsuit also accuses Microsoft, which invested $1 billion in OpenAI in 2019 and $10 billion in 2023, of aiding and abetting OpenAI's wrongful conduct. "Microsoft was aware of what OpenAI was doing every step of the way," Molo said.

Defense lawyers will give their closing arguments later on Thursday.

Altman and Brockman were in court for closing arguments, while Musk is accompanying U.S. President Donald Trump in China.

LAWYERS TO ARGUE REMEDIES WHILE JURORS DELIBERATE

OpenAI competes with AI companies such as Anthropic and Musk's smaller xAI, and is preparing for a possible initial public offering that could value the business at $1 trillion.

Microsoft has spent more than $100 billion on its partnership with OpenAI, a Microsoft executive testified.

Musk's xAI, meanwhile, is now part of his space and rocket company SpaceX, which is also preparing a potential blockbuster IPO.

U.S. District Judge Yvonne Gonzalez Rogers is overseeing the trial.

It is unclear when the nine-person jury will begin deliberations.

If there is no verdict before Monday, the judge and lawyers will return to court that day to discuss how OpenAI should be restructured and what damages should be paid if Musk wins.

Gonzalez Rogers will determine remedies and will award none if Musk loses.

The trial comes amid significant public concerns over AI as it penetrates society.

People use AI for myriad purposes such as facial recognition, financial advice, journalism, medical diagnoses, and harmful deep-fakes. Many people express distrust of the technology and worry it could displace people from their jobs.

MUSK'S AND ALTMAN'S SINCERITY WAS CHALLENGED

OpenAI was founded by Altman, Musk and several others in 2015, though Musk left its board in 2018.

The sincerity of Altman and Musk about their goals for OpenAI has been a central issue in the trial, and neither man has emerged unscathed.

OpenAI has tried to show that even Musk supported its creation of a for-profit business to raise money for computing power and fend off rivals such as Google GOOGL.O.

Musk's effort last year to buy OpenAI through an xAI-led consortium has also been a point of dispute, with OpenAI trying to show it was inconsistent with Musk's goals in his lawsuit.

There has also been testimony about Altman's brief 2023 ouster by OpenAI's board, which also challenged his candor, and whether Altman had conflicts of interest through his involvement in companies that worked with OpenAI.

Altman said he has no direct equity stake in OpenAI, though he has a stake in a fund invested in the company.