A U.S. jury on Monday ruled against Elon Musk in his lawsuit against OpenAI, finding the artificial intelligence company not liable to the world's richest person for allegedly straying from its original mission to benefit humanity.

In a unanimous verdict, the jury in the Oakland, California, federal court said Musk had brought his case too late.

The trial began on April 28. It has widely been seen as a critical moment ​for the future of OpenAI and artificial intelligence generally, both in how it should ​be used and who should benefit from it, including financially.

People use AI for myriad purposes, such as education, facial recognition, financial advice, journalism, legal research, medical diagnosis, and harmful deep-fakes.

Many people express distrust of the technology and worry it could displace people from their jobs.

The verdict followed 11 days of testimony and arguments, during which Musk's and Altman's credibility came under repeated attack.

Each side accused the other of being more interested in money than serving the public.

In his closing argument, Musk's lawyer Steven Molo ​reminded jurors that several witnesses questioned Altman's candour or branded him a liar, and that Musk ​did not give an unqualified yes when asked during the trial if he was completely trustworthy.

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

Musk accused OpenAI of wrongfully seeking to enrich investors and insiders at the nonprofit's expense and of failing to prioritise AI's safety. He also contended that Microsoft knew all along that OpenAI cared more about money than being altruistic.

OpenAI countered that it was Musk who saw dollar signs, and that he waited too long to claim that OpenAI breached its founding agreement to build safe artificial intelligence to benefit humanity.

"Mr. Musk may have the ​Midas touch in some areas, but not in AI," William Savitt, a ​lawyer for OpenAI, ⁠said in his closing argument.

OpenAI competes with AI companies such as Anthropic and 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 is now part of his space and rocket company, SpaceX, which is preparing for an IPO that could exceed OpenAI's in size.