Elon Musk Testifies xAI Partly Used OpenAI Models to Train Grok in California Court

Elon Musk testified in a California federal court on Thursday that xAI “partly” used OpenAI models to train Grok, according to TechCrunch’s report as cited by Decrypt and directly echoed by The Verge.

“Elon Musk took the stand Thursday, accusing OpenAI of stealing a charity before he admitted that his own AI startup, xAI, had “partly” distilled OpenAI’s models to build Grok”

Benzinga

In the same exchange, Musk was asked whether xAI had used distillation techniques on OpenAI models to train Grok, and he answered “Partly.”

Benzinga

TechCrunch described the question as whether xAI had used distillation techniques on OpenAI models to train Grok, noting that Musk asserted it was a general practice among AI companies before answering “Partly.”

The Verge similarly reported that Musk said it was “partly” true that xAI had used model distillation to improve xAI’s models, and it quoted Musk’s “Partly” response when pressed if that was a yes.

Decrypt added that Musk made the statement while testifying in a California federal court where he is suing OpenAI, CEO Sam Altman, and co-founder Greg Brockman, and it said the trial began this week.

Benzinga reported that Musk took the stand Thursday and, under cross-examination from OpenAI lead counsel William Savitt on day three of the federal trial in Oakland, responded “Generally AI companies distill other AI companies” and then “partly” when pressed for yes or no.

Firstpost likewise said the California court questioned Musk on whether xAI had used distillation techniques on OpenAI models to train Grok, and it reported Musk’s “partly” answer and the “Generally A.I. companies distill other A.I. companies” line.

Multiple outlets described distillation as a method where one AI model is used to train another, and they tied the practice to the broader legal fight over OpenAI’s shift from nonprofit to for-profit.

Decrypt said distillation “refers to training a new AI system by querying an existing model through its public interface or API and using those outputs as learning signals,” framing it as a way to replicate model behavior at lower cost.

BFM

TechCrunch similarly explained that the war over distillation has focused on third-party efforts to train new AI models by prompting publicly accessible chatbots and APIs, calling the process “distillation.”

The Verge described the same concept as “model distillation, a common industry practice by which one larger AI model acts as a “teacher” of sorts to pass on knowledge to a smaller AI model, the “student.”

It also noted that distillation can be used legitimately within companies using one of their own AI models to train another, while also being used by smaller labs to try to get their models to mimic the performance of a larger competitor’s model.

Decrypt added that Musk’s testimony indicates the method is being used by U.S.-based AI companies, not only foreign competitors, while also saying “The legal boundaries remain unclear.”

Benzinga stated that distillation is “banned by OpenAI’s terms of service,” and it connected the admission to Musk’s lawsuit seeking $150 billion in damages.

The distillation admission was delivered in the context of Musk’s lawsuit against OpenAI, CEO Sam Altman, and co-founder Greg Brockman, with the trial described as beginning this week in a California federal court.

“In a stunning courtroom admission on Thursday, Elon Musk testified that his artificial intelligence company, xAI, used distillation techniques on OpenAI’s models to train its own chatbot, Grok”

Bitcoin World

Decrypt said Musk is suing OpenAI, CEO Sam Altman, and co-founder Greg Brockman, and it said the trial began this week and will examine the company’s governance and the broader AI landscape.

Benzinga reported that Musk is suing OpenAI for $150 billion in damages, alleging the start-up betrayed its founding nonprofit mission, and it placed the testimony on day three of the federal trial in Oakland.

TechCrunch said Musk is in the process of suing OpenAI, CEO Sam Altman, and Greg Brockman, alleging they breached the original nonprofit mission for OpenAI by shifting the entity to a for-profit structure.

Firstpost added that Musk’s testimony was in a legal case involving Sam Altman, alleging that OpenAI’s non-profit entity still existed and retained control over the for-profit company it created, and it said Musk’s testimony concluded on Thursday.

Decrypt also said Musk made the statement Thursday while testifying in a California federal court, where he is suing OpenAI, CEO Sam Altman, and co-founder Greg Brockman.

Benzinga further described courtroom dynamics, saying Judge Yvonne Gonzalez Rogers blocked Musk’s lawyers from introducing expert testimony on AI extinction risk Thursday and that she remarked “plenty of people do not want to put the future of humanity in Mr. Musk’s hands.”

It also reported that Altman, Microsoft CEO Satya Nadella and former OpenAI CTO Mira Murati are all slated to testify later in the trial, which is expected to run roughly four weeks.

Alongside the courtroom admission, TechCrunch and Firstpost described how OpenAI, Anthropic, and Google have responded to distillation concerns through initiatives connected to the Frontier Model Forum.

TechCrunch said OpenAI, Anthropic, and Google have reportedly launched an initiative through the Frontier Model Forum to share information about how to combat distillation attempts from China, describing the methods as “typically involve systematic querying of models to understand their inner workings.”

Business Insider

It added that “To stop the efforts, frontier labs are working to prevent users from making suspicious mass queries,” and it said OpenAI did not respond to a request for comment on Musk’s admission at press time.

Firstpost similarly said “To curb distillation, OpenAI, Anthropic, and Google have launched initiatives through the Frontier Model Forum to share information on detecting and countering such practices,” and it described the systems as involving “systematically querying models to understand their inner workings.”

It also said “To prevent misuse, frontier labs are also working to block suspicious large-scale querying patterns,” and it described those as attempts to prevent misuse by blocking suspicious mass queries.

Decrypt said earlier in the same broader environment that Anthropic accused several Chinese AI developers of using fraudulent accounts to extract large volumes of responses from its Claude chatbot to train competing systems, and it said the White House warned of “industrial-scale” campaigns using proxy accounts and jailbreaks to replicate U.S. AI capabilities.

Decrypt also framed the legal uncertainty by saying “Distillation is not explicitly illegal, but it can raise questions about whether it violates platform rules or terms governing API use.”

The Verge added that distillation has incited more controversy among AI labs because “the lines for what’s legal — and what violates a company’s certain terms or policies — often fall within a gray area.”

Outside the courtroom, several outlets tied Musk’s testimony and distillation admission to the wider Musk-versus-Altman conflict and to public disputes over safety and content moderation.

“The entrepreneur reinforces his bet on AI-powered video through xAI, with the aim of gaining ground and attracting users after OpenAI's strategic retreat”

Business Insider España

Cryptopolitan reported that Sam Altman and Elon Musk clashed publicly on X over AI safety and the mental health risks tied to ChatGPT, saying Altman criticized Musk’s xAI chatbot Grok for content moderation failures as Musk warned users against ChatGPT.

Business Insider España

It quoted Musk telling users not to let their loved ones use ChatGPT and said Altman responded that ChatGPT is used by nearly a billion people, while also saying OpenAI would keep trying to improve safety while recognizing the delicate and tragic nature of these cases.

La Razón described the relationship as having ended in a frontal clash between Sam Altman and Elon Musk, and it said Musk posted on X advising his followers not to let their loved ones use ChatGPT, wrapped in controversy over the deaths of nine users.

It also said Altman erupted at Musk again, quoting Altman: "I'm not even going to start talking about some of Grok's decisions".

Les Numériques shifted to a different legal thread, reporting that Elon Musk accuses a former employee of stealing top-secret information on behalf of OpenAI, and it said xAI asked the court to issue a temporary restraining order forcing the employee to relinquish access to all his personal devices and online storage services and to return all confidential material to the company.

Business Insider España reported that Musk sped up AI-powered video efforts after OpenAI’s withdrawal, quoting Musk: 'We are redoubling our efforts.'