Ineffable Intelligence, a British AI lab founded by former DeepMind researcher David Silver, has raised $1.1 billion at a $5.1 billion valuation in a round led by Sequoia Capital and Lightspeed Venture Partners, with participation from Index Ventures, Google, Nvidia, and the UK’s Sovereign AI fund.
Silver, a University College London professor who spent over a decade leading DeepMind’s reinforcement learning team, is the researcher behind AlphaZero — the program that mastered chess and Go through self-play alone, without human examples. Ineffable Intelligence aims to apply the same principle at a far broader scale, building a “superlearner” capable of discovering knowledge and skills autonomously through reinforcement learning rather than human-generated training data.
The raise positions Ineffable alongside a wave of researcher-founded AI labs attracting outsized early funding. Last month, Turing Award winner Yann LeCun’s AMI Labs raised $1.03 billion, while DeepMind alumnus Tim Rocktäschel’s Recursive Superintelligence reportedly secured $500 million. All three companies have strong London ties, reinforcing the city’s growing status as an AI hub built significantly around DeepMind’s alumni network.
Silver said any personal proceeds from Ineffable would be donated to high-impact charities.
