A decade-old personal bitterness has completely transformed today’s AI landscape. A new report by The Wall Street Journal reveals the full history of the deep feud between Dario Amodei and OpenAI’s leadership—and it’s not just about technical disagreements.

It all began in 2016 in a shared apartment on Delano Street in San Francisco. Dario and his sister Daniela lived there, and Greg Brockman from OpenAI often visited. One day, in a conversation, a fundamental difference came to light—Brockman wanted all information about AI to be public, while Dario believed sensitive information should first go to the government. That small disagreement would later send both companies down entirely different philosophical paths.

When Dario joined OpenAI, everything was fine at first. He and Brockman would stay up all night teaching AI agents to play games. But after working together for four years, tensions kept rising over power and recognition. In 2017, when Elon Musk asked for a list of employees and 10–20% were laid off, Dario found it ruthless. At the same time, when an ethics adviser at OpenAI suggested coordinating with the government, Brockman saw it as “selling AGI to the United Nations Security Council.” Dario felt it was treason.

In 2018, Sam Altman took over at OpenAI. He made a deal with Dario—Brockman and Ilya Sutskever would not be given control. But soon Dario realized Altman was making separate promises to both of them. Trust broke down.

When development of the GPT series began, intense clashes erupted among management. Dario kept Brockman away from the project, while Daniela—who was working with Alec Radford—threatened to resign. After the success of GPT-2 and GPT-3, Dario’s standing rose, but he felt Altman was downplaying his contributions. When Brockman talked about OpenAI’s constitution on a podcast and Dario wasn’t invited, he was furious. When he learned that Brockman and Altman were going to meet President Obama and he had been left out, the tension hit a peak.

A direct confrontation took place outside a meeting room. Altman accused the Amodei siblings of encouraging colleagues to speak against him. They denied it. Altman said he’d heard it from someone else, so Daniela immediately called that person—and the person said they knew nothing. Altman quickly walked back his statement.

In early 2020, Altman asked managers to review each other. Brockman wrote a harsh critique accusing Daniela of abusing her power. Daniela responded point by point. The debate escalated so much that Brockman even suggested withdrawing his review.

By the end of 2020, Dario’s team had already decided to leave. Altman went to Dario’s home to try to stop him, but Dario said plainly—they would report directly to the board and couldn’t work with Brockman. Before leaving, Dario wrote a long memo dividing AI companies into two categories: “market-based” and “public-interest-based.” His ideal ratio was—75% public interest, 25% market.

A few weeks later, Dario, Daniela, and about a dozen employees started Anthropic, leaving OpenAI behind. And today, five years later, both companies are valued at more than $3 trillion. They are competing against each other for IPOs.

Dario’s internal language has become extremely intense. He compared the dispute between Elon Musk and Sam Altman to a “fight between Hitler and Stalin.” He called Brockman’s donation of $25 million to a Trump-supporting super PAC “bad.” He described OpenAI as “tobacco companies” that deliberately sell harmful products. After a Pentagon controversy, he called OpenAI “liar” on Slack and wrote, “This points to the same behavioral pattern I repeatedly see in Sam Altman.”

Anthropic viewed its branding internally as a strategy to create “healthier alternatives.” This year, at the Super Bowl, they ran an advertisement that didn’t name OpenAI directly, but criticized the company’s chatbot for putting ads in it.

In February 2026, a moment captured in a group photo at the AI summit in New Delhi said it all. Indian Prime Minister Modi and other tech leaders stood with their hands raised, while both Dario and Altman stood apart—only awkwardly touching elbows. A decade of bitterness, now on full display to the world.