Thinking Machines Lab is in talks for a follow-on round seeking at least $1 billion at a valuation of at least $40 billion, per a Sept. 3 report by The Information, quadrupling its $10 billion pre-money valuation from its $2 billion seed round in July 2025 led by Andreessen Horowitz — though below the over $50 billion it sought late last year and the up to $60 billion discussed in November. The startup, founded in early 2025 by former OpenAI CTO Mira Murati, is generating at least a few hundred million dollars in annualized revenue selling tools for businesses to customize AI models on their own data while offering open-weight models for free. The new capital would be used to train models, rent computing infrastructure and hire employees, with existing investor Accel considering leading the round and Nvidia — an investor in the July round and partner in a March multiyear deal for at least 1 gigawatt of Nvidia chips — in discussions to participate.