In a lawsuit filed late Thursday, multibillionaire Elon Musk claims OpenAI, the artificial intelligence developer he helped launch in 2015 and the company behind ChatGPT, DALL-E and other advanced, AI-driven tools, has breached promises made in its founding documents and prioritizes profit motive over serving the public good.

Musk, the sole plaintiff in the case, names OpenAI, its CEO and co-founder Sam Altman and others as defendants in a suit that alleges the company is “irrevocably dedicated” to developing technology that “will benefit the public and the corporation will seek to open source technology for the public benefit when applicable. The corporation is not organized for the private gain of any person.”

Musk’s suit points to an early agreement among the OpenAI founders, which includes Musk, Altman and Greg Brockman, who is also a named defendant in the filing, that the new endeavor “would be a nonprofit developing (artificial general intelligence) for the benefit of humanity, not for a for-profit company seeking to maximize shareholder profits; and ... would be open-source, balancing only countervailing safety considerations, and would not keep its technology closed and secret for proprietary commercial reasons.”

But Musk says Altman, Brockman and OpenAI set that founding agreement “aflame” in 2023 when they launched the latest iteration of its AI-driven chatbot, ChatGPT-4, in March 2023. Musk claims that while previous work done on the ChatGPT platform was performed in an open and transparent manner, the coding and data training behind GPT-4 was kept concealed from everyone except OpenAI’s funding partner, Microsoft.

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“At this time, Mr. Altman caused OpenAI to radically depart from its original mission and historical practice of making its technology and knowledge available to the public. GPT-4′s internal design was kept and remains a complete secret except to OpenAI — and, on information and belief, Microsoft,” the lawsuit reads.

Musk claims he “was a moving force behind the creation of OpenAI” and contributed “a majority of its funding in its first several years, advising on research directions, and most importantly, recruiting some of the world’s leading scientists and engineers to work at the nonprofit venture, including chief scientist Ilya Sutskever.”

Musk also alleges OpenAI concealed details about GPT-4 behind a shroud of secrecy expressly to seek profit from its latest chatbot innovations.

“On information and belief, this secrecy is primarily driven by commercial considerations, not safety,” the lawsuit reads. “Although developed by OpenAI using contributions from plaintiff and others that were intended to benefit the public, GPT-4 is now a de facto Microsoft proprietary algorithm, which it has integrated into its Office software suite.”

In January 2023, Microsoft announced a third phase of the company’s “long-term partnership with OpenAI through a multiyear, multibillion-dollar investment to accelerate AI breakthroughs to ensure these benefits are broadly shared with the world.”

The infusion of cash, reportedly worth around $10 billion over time, was intended to help turbocharge OpenAI’s fast moving machine learning and artificial intelligence innovations and, at the same time, provide Microsoft commercial access to potentially very powerful new technology to challenge Google’s dominance in search and AI advancements.

The commitment followed two previous rounds of Microsoft investment in OpenAI and, per the announcement, created the opportunity for Microsoft to incorporate OpenAI’s artificial intelligence advancements into its own new and/or existing products.

“This agreement follows our previous investments in 2019 and 2021,” read a January 2023 Microsoft blog post. “It extends our ongoing collaboration across AI supercomputing and research and enables each of us to independently commercialize the resulting advanced AI technologies.”

While the company launched as a nonprofit, it modified its business model in 2019 and became a “capped profit company,” a designation it describes as a hybrid of the nonprofit and for-profit models. Musk parted ways with company leadership in 2018 when he resigned from the OpenAI board, but had continued investment activity until 2020, according to the lawsuit. Musk has since gone on to form his own artificial intelligence innovation startup, called xAI.

Musk’s claims against OpenAI and defendants include breach of contract, breach of fiduciary duty and unfair business practice. He is asking the court to compel OpenAI to make all of its research and technology available to the public and prohibit the company, or any of its funding partners, from making money from OpenAI products.

OpenAI has so far declined to publicly comment on the lawsuit.