AI chip startup Etched has raised $700 million at a $21 billion valuation, led by quantitative trading firm Jane Street, which tested and subsequently bought the company's hardware. The pace of the valuation increase is remarkable even by the standards of the current AI boom, reflecting strong investor confidence in Etched's approach to accelerating AI inference, the computing process that occurs after a user submits a prompt to an AI model.

Etched was valued at just $5 billion in December, before raising a $300 million Series C round at $10.3 billion in July, meaning its valuation has now doubled again within a month, adding nearly $11 billion. The company sells complete systems it calls "frontier inference clusters," featuring a custom low-voltage prefill chip and a new "cluster-scale memory" interconnect designed to speed up both stages of inference while cutting costs. Etched has also moved away from its original premise of etching a single model onto each chip, with its systems now able to run any frontier AI model. Existing backers including Sequoia Capital, Andreessen Horowitz and Kleiner Perkins also took part in the round.