Andrej Karpathy, one of the founding members of OpenAI and former director of AI at Tesla, has joined rival AI company Anthropic, maker of the Claude series of models.

He made the announcement on social media app X, saying: “I think the next few years at the frontier of LLMs will be especially formative. I am very excited to join the team here and get back to R&D.”

Karpathy is an influential figure in the world of AI, having not only co‑founded the largest AI company in the world but also worked to develop self‑driving capabilities at car manufacturer Tesla prior to his departure in 2022.

Anthropic told Reuters that he has joined its pre‑training team, which is responsible for large‑scale training that provides the knowledge base for Claude. He began work this week and sits on the team of Nick Joseph, the company’s head of pre‑training, the news outlet added.

Karpathy is the second OpenAI founder to join Anthropic. John Schulman left OpenAI for its rival in 2024, though he left after a year to become chief scientist at Thinking Machines Lab, itself founded by OpenAI’s former chief technology officer Mira Murati.

Anthropic is currently the second‑largest AI company in the world after OpenAI in terms of valuation, but recently surpassed the company based on annualised revenue predictions, which surpassed $30 billion in 2026, largely due to its enterprise streams.

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