Chai Discovery Raises $400M in Series C Funding Round

The round also saw participation from Bain Capital Ventures, Battery Ventures, Baillie Gifford, BDT and MSD, Sapphire Ventures, Avra Capital, Thrive Capital, OpenAI, Oak HC/FT, Menlo Ventures, General Catalyst, Glade Brook, Avenir, Lachy Groom, and Yosemite.

The company will use the funding to expand its operations and accelerate research and development of its products.

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Chai Discovery develops AI models that help speed up early-stage drug discovery by predicting how molecules interact and designing new ones. Its platform is used by leading pharmaceutical companies, including Eli Lilly and Pfizer, to help researchers develop better treatments faster, even for diseases that have been difficult to target with traditional drug discovery methods.

Its latest AI model, Chai-3, improves the success rate of finding drug targets and creates antibodies that bind more strongly to their intended targets. Earlier, Chai-2, launched in 2025, became the first AI-platform to design entirely new antibodies with double digit experimental success rates marking a major advance over previous computational 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.

“At Kleiner Perkins, we’ve always believed the most important companies begin with a fundamental truth and a team with the ambition, clarity, and velocity to build something enduring,” said Ilya Fushman, partner at Kleiner Perkins. “Chai has both. Their models are already being used by some of the world’s largest pharma companies, and the speed at which this team is advancing the frontier, technically and commercially, is remarkable.

"Drug discovery is one of the hardest problems in science. For a long time, there's been a dream that AI will solve it," said Pat Grady, partner at Sequoia Capital. "Chai's product velocity and real-world partnerships with Eli Lilly, Pfizer, and more of the biggest names in pharma are starting to turn this dream into a reality. Josh and Jack move with a focus and precision that are rare in this space."

About Chai Discovery

Founded in 2024 by Joshua Meier, Jack Dent, Matthew McPartlon, and Jacques Boitreaud, San Francisco-based Chai Discovery develops AI technology to help pharmaceutical companies design new medicines faster. Its AI models help scientists understand biology, create new molecules from scratch and tackle drug targets that have been difficult to address using traditional methods.

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