Thinking Machines Lab, the AI lab founded by former OpenAI chief technology officer Mira Murati, is reportedly closing in on a $5 billion funding round led by Accel at a $40 billion pre-money valuation — more than triple the $12 billion valuation on its $2 billion seed round in July 2025. Business Insider reported the talks on 6 November, citing multiple people familiar with the matter, and said the deal could close within days.
To be clear, the round is reported, not announced: Thinking Machines declined to comment and Accel did not respond, so the terms rest on the report alone. The $40 billion figure is still below the $50 billion the lab sought in abandoned talks last year, and implies roughly $45 billion once the new money is counted.
The timing is no coincidence. On 5 November, the lab shipped Inkling 2 Small, a 594-billion-parameter model built to run AI training jobs, with full weights promised under the Apache 2.0 open licence in the following weeks after safety testing. Its Tinker fine-tuning platform shipped a software development kit update the same day — and open weights let outsiders test the claims.
A $5 billion round, if it closes, would be one of the largest private AI raises ever, and the money would mostly buy computing power — every billion raised by a frontier lab is, in practice, a purchase order for chips. The reported valuation prices talent and compute rather than revenue, and investors are betting Murati’s team can build frontier models from scratch.
What to watch: whether the round is announced within days as reported and at what terms, and whether Inkling 2 Small’s open weights land as promised. Our pages on ChatGPT, Claude and Gemini cover the models this new lab is chasing.
Source: AI Agent Update (via Business Insider)
