Chai Discovery raises $400M Series C at $3.8B valuation with major pharma partnerships

Chai Discovery closed a $400M Series C round led by Index Ventures at a $3.8B valuation, roughly triple its December 2025 valuation. The company has signed paid deployments with Eli Lilly, Pfizer, and Novartis. Series C also included participation from Kleiner Perkins, Sequoia, and others.