# Chai Discovery Raises $400M Series C for AI Drug Discovery at $3.8B Valuation

> Chai Discovery, an OpenAI-backed startup building AI models for molecular design, has closed a $400 million Series C led by Index Ventures, with Kleiner Perkins, Sequoia, and Dimension among a large investor group. The round values the company at $3.8 billion, a jump from its $1.3 billion Series B just seven months earlier in December 2025. The momentum is tied to its Chai-3 model, which the company says improves target success rates and designs antibodies with stronger binding affinity, the kind of gains that translate directly into faster, cheaper drug programs. Enterprise customers reportedly already include Pfizer and Eli Lilly, using the platform to predict and optimize drug candidates. AI-for-biology has been one of the most heavily funded corners of the boom, and a valuation nearly tripling in seven months shows investors still believe computational design can meaningfully compress the long, expensive path from molecule to medicine.

_Section: [AI Funding Tracker](https://www.wortins.com/funding) · Source: TheNextWeb · Published Sunday, July 19, 2026_

## Wortins' read

Chai Discovery, an OpenAI-backed startup building AI models for molecular design, has closed a $400 million Series C led by Index Ventures, with Kleiner Perkins, Sequoia, and Dimension among a large investor group. The round values the company at $3.8 billion, a jump from its $1.3 billion Series B just seven months earlier in December 2025. The momentum is tied to its Chai-3 model, which the company says improves target success rates and designs antibodies with stronger binding affinity, the kind of gains that translate directly into faster, cheaper drug programs. Enterprise customers reportedly already include Pfizer and Eli Lilly, using the platform to predict and optimize drug candidates. AI-for-biology has been one of the most heavily funded corners of the boom, and a valuation nearly tripling in seven months shows investors still believe computational design can meaningfully compress the long, expensive path from molecule to medicine.

## Source

[Read the full story at TheNextWeb](https://thenextweb.com/news/chai-discovery-400m-series-c-ai-drug-discovery)

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