Inference chip startup Etched has secured a follow-on funding round of $700 million, led by Jane Street, at a valuation of $21 billion. This latest investment, which includes participation from Kleiner Perkins and Sequoia, more than doubles the company's previous valuation. Etched plans to use these funds to further develop its inference accelerators, which offer multiple times the FLOPs density of rivals due to their voltage-optimized math blocks.