Chai Discovery, an AI-driven drug discovery startup barely two years old, is in discussions to raise $400 million at a $3.4 billion valuation.
The company’s backers include OpenAI, Thrive Capital, Menlo Ventures, General Catalyst, and Oak HC/FT on the tech side, and Pfizer and Eli Lilly on the pharma side.
From zero to $3.4 billion in two years
Founded in 2024 by Joshua Meier, Jack Dent, Matthew McPartlon, and Jacques Boitreaud, Chai Discovery raised roughly $30 million in seed funding in 2024, followed by a $70 million Series A in August 2025. The $130 million Series B in December 2025 valued the company at $1.3 billion. The current $400 million round would nearly triple that valuation to $3.4 billion.
Chai Discovery’s flagship Chai-2 model can design novel antibodies from scratch, a process known as de novo antibody design, with hit rates of approximately 20%. Prior computational methods achieved hit rates of roughly 0.1%, making the company’s AI roughly 200 times more effective at finding viable drug candidates.
