Chai Discovery announced a $400 million Series C financing to accelerate the development and deployment of its AI-driven molecular design platform. The round valued Chai Discovery at $3.8 billion. It was led by Index Ventures alongside Kleiner Perkins, Sequoia Capital, and Dimension. New investors in the round included Bain Capital Ventures, Battery Ventures, Baillie Gifford, BDT & MSD, Sapphire Ventures, Avra Capital, and other notable investors. Existing investors Thrive Capital, OpenAI, Oak HC/FT, Menlo Ventures, General Catalyst, Glade Brook, Avenir, Lachy Groom, and Yosemite also participated.
Chai Discovery builds AI models designed to accelerate pre-clinical drug discovery by predicting and reprogramming interactions between molecules. The company’s software platform gives scientists at pharmaceutical and life sciences companies access to those models, helping them design better molecules and pursue difficult targets.
The company said its platform is already being used by leading pharmaceutical companies, including Eli Lilly and Pfizer. Chai Discovery’s broader mission is to bring the precision and predictability of engineering to drug discovery, including for “hard-to-drug” and “undruggable” targets that traditional discovery methods have struggled to address.
The financing comes as AI drug discovery moves from early promise into commercial deployment. Chai Discovery said its models are being used by partners to design molecules faster, improve work against difficult targets, and create new paths for therapeutic development.
Chai Discovery’s latest model, Chai-3, is designed to improve target success rates and binding affinity compared to its predecessor. The company said Chai-3 has produced antibodies that bind substantially more tightly to intended targets.
The company previously released Chai-2 in 2025. Chai Discovery said Chai-2 was the first zero-shot generative platform for fully de novo antibody design to achieve double-digit experimental success rates, representing a major advance over prior computational methods.
Founded in 2024, Chai Discovery is based in San Francisco. The company was founded by Joshua Meier, Jack Dent, Matthew McPartlon, and Jacques Boitreaud.
The founding team brings experience from OpenAI, Meta FAIR, Stripe, molecular design, and academic research. Chai Discovery is building models designed to reason about biological structure and function, generate new molecular designs from scratch, and support pharma teams working on some of the most challenging areas of drug discovery.
The Series C financing gives Chai Discovery additional capital to expand research and development, support commercial deployments, and continue building its platform for AI-enabled molecular design.
KEY QUOTES:
“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. 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.”
Joshua Meier, Co-Founder and CEO of Chai Discovery
“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. From the moment I met this team, I knew they were the ones to tackle one of medicine’s hardest problems. 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.”
Nina Achadjian, Partner at Index Ventures
“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. 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 being transformed by AI, and Chai is building the platform that can help define what comes next.”
Ilya Fushman, Partner at Kleiner Perkins
“Drug discovery is one of the hardest problems in science. For a long time, there’s been a dream that AI will solve it. 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.”
Pat Grady, Partner at Sequoia Capital
“This is the largest check we’ve ever written at Dimension, and we are beyond thrilled for this next phase of growth and continued acceleration of R&D for the Chai team. As the pre-eminent firm at the intersection of science and compute, we bring a discerning approach to evaluating the companies in our portfolio. As early investors in Chai, our strong conviction in the team and their lightning speed innovation has only grown over time. We are excited to be on this journey with them.”
Zavain Dar, Founder at Dimension
