Elon Musk is suing OpenAI and its chief executive Sam Altman over what he says is a betrayal of the ChatGPT maker’s founding aims of benefiting humanity rather than pursuing profits.

In a lawsuit filed at San Francisco Superior Court, billionaire Mr Musk said that when he bankrolled OpenAI’s creation, he secured an agreement with Mr Altman and Greg Brockman, the president, to keep the AI company as a non-profit that would develop technology for the benefit of the public.

Under its founding agreement, OpenAI would also make its code open to the public instead of walling it off for any private company’s gains, the lawsuit says.

However, by embracing a close relationship with Microsoft, OpenAI and its top executives have set that pact “aflame” and are “perverting” the company’s mission, Mr Musk alleges in the lawsuit.

“OpenAI, Inc has been transformed into a closed-source de facto subsidiary of the largest technology company in the world: Microsoft,” the lawsuit filed on Thursday says.

“Under its new board, it is not just developing but is actually refining an AGI to maximise profits for Microsoft, rather than for the benefit of humanity.”

AGI refers to artificial general intelligence, which are general purpose AI systems that can perform just as well as — or even better than — humans in a wide variety of tasks.

Mr Musk is suing over breach of contract, breach of fiduciary duty and unfair business practices. He also wants an injunction to prevent anyone, including Microsoft, from benefiting from OpenAI’s technology.

He was an early investor in OpenAI when it was founded in 2015 and co-chaired its board alongside Mr Altman.

Mr Musk’s lawsuit said he invested “tens of millions” of dollars in the non-profit research laboratory.

He resigned from the board in early 2018 in a move that OpenAI said would prevent conflicts of interest at the time as the Tesla CEO was recruiting AI talent to build self-driving technology at the electric car maker.

Mr Musk has since said he also had disagreements with the start-up’s direction, but he continued to donate to the non-profit.

Later that year, OpenAI filed papers to incorporate a for-profit arm and began shifting most of its workforce to that business, but retained a non-profit board of directors that governed the company.

Microsoft made its first one-billion-dollar investment in the company in 2019 and the next year, signed an agreement that gave the software giant exclusive rights to its AI models.

That licence is supposed to expire once OpenAI has achieved artificial general intelligence, the company has said.

When the non-profit board abruptly fired Mr Altman as chief executive late last year, for reasons that still haven’t been fully disclosed, it was Microsoft that helped drive the push that brought him back as chief executive and led most of the old board to resign.

Mr Musk’s lawsuit alleged that those changes caused the checks and balances protecting the non-profit mission to “collapse overnight”.