Elon Musk and Sam Altman have renewed their billionaire brawl as both seek to sell investors on their own vision of the AI revolution.

The longstanding feud between the OpenAI cofounders reignited over the weekend when the world’s richest man chimed in about Apple’s lawsuit against OpenAI.

On Friday, Apple sued OpenAI and two former Apple employees who joined the AI startup, alleging they stole company secrets to help build up OpenAI’s hardware business. OpenAI has denied the claims, telling multiple outlets it “has no interest in other companies’ trade secrets.”

Musk pounced on the Apple news to lambast Altman. “Scam Altman strikes again,” Musk wrote, reviving a Trumpian nickname he has previously used to describe the OpenAI CEO. Over the next day, the SpaceX chief doubled down, replying to several other posts with put-downs like “He takes scamming to a whole new level” and “He might literally love scamming more than any human alive!”

Altman shot back in a reply on X Saturday in which he claimed Musk is “the one sellling [sic] public market investors on short-term space datacenters.”

Musk then got in one last jab: “We start flying them next year,” he said referring to the orbital data centers Altman mentioned. “Maybe you can come see them if your parole officer approves. After stealing an open source AI charity, you then stole all of Apple’s phone technology! Wow…”

Musk’s final missive alludes to a claim that is central to the origin of the feud—that Altman allegedly “stole” OpenAI.

Feud origins

Back in 2015, Musk and Altman worked together closely to get OpenAI off the ground. At the time, Altman was president of the startup accelerator Y Combinator, famous for helping launch companies like Airbnb and DoorDash, while Musk was already a multibillionaire and was running Tesla along with SpaceX simultaneously.

The pair joined forces with several other cofounders to start OpenAI as a nonprofit AI research lab “to advance digital intelligence in the way that is most likely to benefit humanity as a whole, unconstrained by a need to generate financial return.” One of the early motivations was reportedly to prevent Google from getting a monopoly over AI.

Yet the pair had a falling out when Musk reportedly decided OpenAI was falling behind in the AI race. In 2018, he made an offer to take control of the company and considered folding it into Tesla after having already invested tens of millions of dollars, with a total of roughly $1 billion promised over the next several years.

But Altman and other original OpenAI team members rejected the takeover proposal. Musk left OpenAI’s board and cut off the funding he had pledged. He would later lead a group of investors that last year offered to buy the company for $97.4 billion.

After the release of ChatGPT in 2022 made OpenAI one of the hottest startups on the planet, Musk and Altman’s feud spilled into the courtroom.

Musk sued OpenAI and Altman in 2024, alleging Altman had gone against OpenAI’s original nonprofit mission by constructing an “opaque web of for-profit OpenAI affiliates” and prioritizing commercial returns. As part of his suit, Musk asked for $150 billion in damages that would be destined for a charitable trust and requested OpenAI’s for-profit structure be reversed.

OpenAI argued that Musk turned against the organization only after his attempt to control it failed. When OpenAI rejected his proposal in 2018, Musk said its “probability of success was zero” and that he planned to build an artificial-general-intelligence competitor within Tesla, according to a blog post published by the company.

A jury in May found Musk did not meet the statute of limitations for his case and tossed out the suit. Musk has said he will appeal the ruling.

While the lawsuit may have been dismissed, Musk and Altman’s feud is anything but. Musk launched his own AI company xAI in 2023 and released the large language model Grok in the same year. Earlier this year, Musk’s SpaceX acquired xAI and later rebranded itself as SpaceXAI, billing its newfound AI business as an essential part of the company’s future prospects and valuation.

SpaceX went public in a record-setting IPO in June, the same month OpenAI confidentially filed for its own IPO.

Last week, the tension between the two companies erupted again as OpenAI released its new model GPT-5.6 Sol one day after SpaceXAI announced Grok 4.5.

“There are a lot of benchmarks that suggest 5.6 sol is the best model in the world right now,” wrote Altman on X, “but the most reliable way to tell is that elon is obsessed with me again.”