Chai Discovery has announced a $400 million Series C financing to support the continued development of its artificial intelligence platform for molecular design and pre-clinical drug discovery. The round values the San Francisco-based company at $3.8 billion and will be used to accelerate research, product development and commercial deployment.
The company develops AI models that predict and reprogram molecular interactions, enabling pharmaceutical and life sciences organisations to generate entirely new molecular designs. Its platform is currently being used by partners including Eli Lilly and Pfizer to pursue therapeutic targets that have traditionally been considered difficult or impossible to address using conventional discovery approaches.
"Tomorrow's medicines should be designed with the precision, speed and scale of modern engineering, and this support helps us move faster towards that future," said Joshua Meier, co-founder and CEO of Chai Discovery. "AI drug discovery has moved from promise to deployment, and Chai's models are already unlocking progress for our partners—enabling them to design better molecules, move faster against difficult targets, and take on challenges that traditional discovery methods have struggled to solve."
The company's latest model, Chai-3, is designed to improve target success rates and binding affinity compared with its predecessor by producing antibodies that bind more tightly to intended targets. Chai also highlighted that Chai-2, introduced in 2025, was the first zero-shot generative platform for fully de novo antibody design to achieve double-digit experimental success rates.
Investors participating in the financing said the company has combined technical progress with commercial adoption. Nina Achadjian, partner at Index Ventures, said, "It's rare to find founders who have the technical brilliance to push the frontier and the clarity to turn that into real commercial traction." She added, "Josh, Jack, Matt, Jacques and the team aren't building toward real-world deployment — they're already there, with deployments already at the world's largest pharma companies. We're excited to partner with the Chai team as they build the platform for a new era of drug discovery."
Founded in 2024, Chai Discovery is focused on applying AI to generate new molecular designs from scratch and help pharmaceutical companies pursue biological targets that have proven challenging for traditional drug discovery methods.
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