Elon Musk’s lawsuit against OpenAI is to go to trial after a US judge said there is plenty of evidence to support the billionaire’s case.

The world’s richest man, who co-founded OpenAI, is suing the ChatGPT developer and its chief executive, Sam Altman, over claims its leaders violated the organisation’s founding mission by shifting to a for-profit model.

The US district judge Yvonne Gonzalez Rogers in Oakland, California, told a hearing there was plenty of evidence that suggested OpenAI’s leaders made assurances that its original nonprofit structure was going to be maintained.

She said there were enough disputed facts to let a jury consider the claims at a trial scheduled for March, rather than decide the issues herself. Rogers said she would issue a written order after the hearing that addresses OpenAI’s attempt to throw out the case.

The court dispute comes amid a broader showdown over dominance in the market for generative artificial intelligence. Musk’s xAI and its chatbot Grok are competing with OpenAI and other technology developers.

Musk is seeking unspecified monetary damages from what he calls “ill-gotten gains” by OpenAI.

In a statement after the hearing, OpenAI said: “Mr Musk’s lawsuit continues to be baseless and a part of his ongoing pattern of harassment, and we look forward to demonstrating this at trial.”

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

Steven Molo, a lead trial attorney for the billionaire and xAI, said after the hearing: “We look forward to presenting all the evidence of the defendants’ wrongdoing to the jury.”

Musk contends he contributed about $38m (£28m), roughly 60% of OpenAI’s early funding, along with strategic guidance and credibility, based on assurances that the organisation would remain a nonprofit dedicated to the public benefit.

The lawsuit accuses OpenAI co-founders Altman and Greg Brockman of plotting a for-profit switch to enrich themselves, culminating in multibillion-dollar deals with Microsoft and a recent restructuring.

OpenAI, Altman and Brockman have denied the claims, and have described Musk as “a frustrated commercial competitor seeking to slow down a mission-driven market leader”.

Microsoft, which is also a defendant, urged Rogers to throw out Musk’s claims against it. A lawyer for Microsoft said there was no evidence that the company “aided and abetted” OpenAI.

Microsoft has been approached for comment.

Lawyers for OpenAI at the hearing asked Rogers to enter judgment against Musk, contending that he had not shown enough of a factual basis to sustain his allegations including fraud and breach of contract.

OpenAI also contends that Musk failed to bring his allegations in a timely manner. The judge said the jury would be asked to weigh whether the lawsuit was filed outside the statute of limitations.