Top AI researchers continue to jump between leading AI labs as competition for elite talent intensifies, with hiring and retention proving difficult despite enormous pay, prestigious titles, and vast computing resources. The latest high-profile move is Lilian Weng, co-founder of Mira Murati's Thinking Machines Lab, who announced last week she was leaving, citing health toll and a desire for a more focused position. Days later, The Information reported she was rejoining OpenAI to work on recursive self improvement. Weng is the fourth Thinking Machines co-founder to leave within the past year. Google lost two prominent researchers in June as Noam Shazeer left for OpenAI and Nobel Prize in Chemistry winner John Jumper went to Anthropic. Meta has spent heavily to lure researchers to Alexandr Wang's superintelligence operation, only to see several prized recruits quickly decamp, some for OpenAI. Last year, Ilya Sutskever lost the CEO of his startup Safe Superintelligence to Meta. Money matters, with some researchers receiving difficult-to-refuse offers or seeking equity before a potential IPO. A source told Axios that Anthropic CEO Dario Amodei has expressed concern about new talent coming for money rather than mission. Some researchers also worry their bargaining power could diminish as AI systems automate more work. Compensation alone doesn't explain the movement, as researchers care about access to computing power, influence, and freedom to pursue their preferred technical approach.