On July 14, 2026, Chai Discovery announced a $400 million Series C at a $3.8 billion valuation to advance AI-driven molecular design. The round was led by Index Ventures and co-led by Kleiner Perkins, Sequoia Capital, and Dimension, with new investors including Bain Capital Ventures, Battery Ventures, Baillie Gifford, BDT & MSD, Sapphire Ventures, and Avra Capital, and returning investors including Thrive Capital, OpenAI, Menlo Ventures, and General Catalyst. The raise roughly tripled the company’s valuation from its prior round about seven months earlier.
Chai Discovery builds AI models that predict and redesign molecular interactions for pre-clinical drug discovery. Its Chai-2 model, released in 2025, was the first zero-shot generative platform to achieve double-digit experimental success rates for fully de novo antibody design. The company says its newer Chai-3 model materially improves target success rates and binding affinity, producing antibodies that bind targets substantially tighter than its predecessors. Named pharmaceutical partners include Eli Lilly and Pfizer.
CEO Joshua Meier framed the mission as making tomorrow’s medicines designable with the precision, speed, and scale of modern engineering. The round is one of the largest of 2026 in AI-for-biology and shows that the structure-prediction wave that began with AlphaFold has matured into a venture category where generative molecular design companies command multi-billion-dollar valuations on experimental results rather than promises.