Ineffable Intelligence, an AI lab in London founded in 2025 by former Google DeepMind researcher David Silver, has raised $1.1 billion in seed funding, bringing its valuation to $5.1 billion, and marking the largest seed round ever in Europe.
Sequoia Capital and Lightspeed Venture Partners led the funding, joined by NVIDIA, Google, DST Global, Index, EQT, BOND, and Flying Fish. The UK government’s Sovereign AI Fund also invested, along with the British Business Bank, which put in $20 million to support AI development in the UK.
TFN reported in February that Silver aimed to raise $1 billion at a $4 billion pre-money valuation. The final round exceeded both goals.
Silver is a professor at University College London and led the reinforcement learning team at Google DeepMind for over ten years before starting Ineffable Intelligence in late 2025. He was key in creating AlphaGo, AlphaZero, AlphaFold, and AlphaProof.
The company is building a “superlearner,” an AI that learns everything from its own experience, without using human-generated data. Unlike today’s large language models, which are trained on internet text, Ineffable uses reinforcement learning.
This funding puts Ineffable among other billion-dollar labs started by top researchers leaving big tech companies. TFN reported earlier that Recursive Superintelligence, started by former DeepMind scientist Tim Rocktäschel, raised $500 million at a $4 billion valuation. Ilya Sutskever’s Safe Superintelligence raised $2 billion at a $32 billion valuation. AMI Labs, co-founded by Turing Award winner Yann LeCun after leaving Meta, raised $1.03 billion at a $3.5 billion pre-money valuation in March.
That effort is picking up speed. Last week, the Sovereign AI Fund quickly invested capital since its £500 million launch. The British Business Bank has made nine AI investments in the past year, including Wayve and PolyAI, and has supported almost a quarter of all UK university spinout deals from 2022 to 2024.
Silver has also promised to donate all his personal proceeds from Ineffable to high-impact charities through Founders Pledge, calling the company “his life’s work.” It is still unclear whether reinforcement learning at this scale can achieve the superintelligence Silver hopes for. Still, this funding round shows that top investors believe Silver is well-placed to try.
