OAKLAND, California: A legal battle over the origins and direction of one of the world's most prominent artificial intelligence companies escalated, as Elon Musk laid out claims that OpenAI and Microsoft reaped tens of billions of dollars in benefits from his early backing of the startup.

In a federal court filing, Musk said he is seeking up to US$134 billion from the two companies, arguing that they obtained "wrongful gains" stemming from his contributions to OpenAI when it was founded.

According to the filing, OpenAI raised between $65.5 billion and $109.4 billion from Musk's support during its early years, starting in 2015, while Microsoft raised between $13.3 billion and $25.1 billion. The filing was submitted ahead of a trial involving Musk and the two companies.

OpenAI, Microsoft, and Musk's lawyers did not immediately respond to requests for comment outside business hours. OpenAI has previously described the lawsuit as "baseless" and part of a "harassment" campaign by Musk. At the same time, a Microsoft lawyer has said there is no evidence the company "aided and abetted" OpenAI.

Musk left OpenAI in 2018 and now runs xAI, which develops the chatbot Grok, competing with ChatGPT. He alleges that OpenAI abandoned its original mission through a high-profile restructuring into a for-profit entity.

Earlier this month, a judge in Oakland, California, ruled that the case will proceed to a jury trial, which is expected to begin in April.

Musk's filing says he contributed about $38 million to OpenAI, representing roughly 60 percent of its early seed funding. He also helped recruit staff, connect the founders with influential contacts, and lend credibility to the venture at its inception, the filing says.

"Just as an early investor in a startup company may realize gains many orders of magnitude greater than the investor's initial investment, the wrongful gains that OpenAI and Microsoft have earned – and which Mr. Musk is now entitled to disgorge – are much larger than Mr. Musk's initial contributions," Musk argues in the filing.

The calculations cited by Musk were prepared by his expert witness, financial economist C. Paul Wazzan, according to the document.

If the jury finds OpenAI or Microsoft liable, Musk may also seek punitive damages and other penalties, including a potential injunction, the filing said, though it did not specify what form any such injunction might take.