Thinking Machines, the AI lab founded by former OpenAI CTO Mira Murati, is reportedly in talks to raise $1 billion at a valuation of at least $40 billion, with existing backer Accel leading the round.

The valuation is below the $50 billion the company sought late last year. The startup’s annual revenue run rate exceeds $100 million, making the $40 billion valuation a very high multiple.

In July, Thinking Machines introduced an open-weight model called Inkling, which generates revenue through usage-based compute fees for adapting models on proprietary data via its Tinker platform.

The company previously raised a $2 billion seed round at a $12 billion valuation, one of the largest seed financings ever, led by Andreessen Horowitz with participation from Nvidia, GV, Lightspeed, and Conviction Partners.

Several co-founders, including Lilian Weng and Luke Metz, have since left to rejoin OpenAI.