Co-founder who departed on Feb. 27, 2026. His public exit statement did not state a reason. xAI launched in 2023 with Elon Musk and 11 other co-founders; by February 2026, most of the original co-founders had departed (Reuters, Feb. 11, 2026).

Co-founder who led research at xAI. His public exit statement was neutral and did not state a reason. xAI launched in 2023 with Elon Musk and 11 other co-founders; by February 2026, most of the original co-founders had departed (Reuters, Feb. 11, 2026).

Co-founder who led the reasoning team. His public exit statement was neutral and did not state a reason. Departed during a period in which most of xAI's original co-founders left.

Warned 'the world is in peril.' Cited a disconnect between Anthropic's stated safety values and competitive pressures driving actual decisions.

Departed Anthropic in February 2026, announcing plans to pursue something new. His public post did not link his departure to safety or ethics concerns; he is listed for chronology alongside the February 2026 safety-team departures.

Departed Anthropic in February 2026, writing that he was leaving to start something new and praising Anthropic as a 'magical place' with a strong culture. His public post did not link his departure to safety or ethics concerns; he is listed for chronology alongside the February 2026 safety-team departures.

OpenAI fired Beiermeister, the vice president leading its product policy team, citing a discrimination allegation from a colleague — an accusation she called 'absolutely false.' She had opposed ChatGPT's planned 'adult mode' feature, and she and subsequent reporting allege the termination was retaliation for raising safety concerns. The dispute is unresolved.

Said he's 'pretty terrified' by the pace of AI development. Called the pursuit of AGI a 'very risky gamble with the future of humanity.'