Mira Murati’s Thinking Machines Lab closed the largest seed round in AI history in July 2025, raising $2 billion at a $12 billion post-money valuation, according to Reuters and TechCrunch. Four months later, Bloomberg reported the company was seeking $50 billion from new investors. By January 2026, those talks had collapsed without a deal. Today Thinking Machines sits at its original $12 billion valuation, with roughly 140 to 169 employees, two live products, and infrastructure commitments from Nvidia and Google that run into the billions.
The $2B Seed, and the Overshoot That Followed
The seed round closed in July 2025 with a syndicate that included Nvidia, Accel, ServiceNow, Cisco, AMD, and Jane Street. The $12 billion post-money valuation was remarkable for a company with no product and a small team, but investor appetite for frontier AI ventures had by then absorbed OpenAI’s $40 billion raise and Anthropic’s multi-billion funding rounds with relative ease.
Pressure to revalue came quickly. In November 2025, Bloomberg reported Thinking Machines was in discussions with investors at a valuation as high as $55 billion to $60 billion, roughly quadrupling the seed price in under five months. Those talks attracted attention as much for their timing as their size: at that point the lab had shipped just one product, a finetuning API for open-source models, per The Information. By January 2026, multiple media accounts confirmed the financing had not closed. Prospective backers had declined to support the valuation without a more substantial product record.
The valuation did not evaporate; it returned to its seed level, preserving the original investors’ paper value while closing the window on an early mark-up. The episode is a useful marker for where AI investor appetite meets product reality in the current cycle.
Two Products in 16 Months
The finetuning API was Thinking Machines Lab’s first commercial offering, launched alongside Tinker, a developer platform for running and customizing open-source models. The approach positioned the lab as infrastructure rather than a consumer-facing assistant provider. In September 2025, TechCrunch reported Thinking Machines had published research arguing that current AI models produce inconsistent outputs under similar inputs, and proposing training techniques to reduce that variance.
