A London startup betting that reinforcement learning, not LLMs, is the path to superintelligence

Silver left Google DeepMind in late 2025 after more than a decade building AlphaGo, AlphaZero, AlphaStar, and contributing to Gemini. Ineffable Intelligence was incorporated in November 2025 and has no product, no revenue, and no public roadmap.

What it has is a thesis, and a founder whose track record is worth a billion dollars to investors on conviction alone.

Ineffable Intelligence, the London-based AI startup founded by David Silver, the British researcher who led the creation of AlphaGo, AlphaZero, and AlphaStar at Google DeepMind, has been backed by Sequoia Capital and Nvidia at a valuation of $5.1 billion.

The round, one of the largest ever raised by a startup at such an early stage, was led by Sequoia, with Sequoia managing partner Alfred Lin and partner Sonya Huang having flown to London personally to meet Silver and secure the deal.

Nvidia’s venture arm contributed at least $250 million ...