Mira Murati’s Thinking Machines Lab is about to get a lot richer. Business Insider reported on Thursday, November 6, that the AI startup is set to close a $5 billion funding round led by Accel at a $40 billion pre-money valuation, a deal that could close as soon as this week. For Thinking Machines Lab funding, the numbers tell the story: the new price is more than triple the $12 billion valuation the company carried after its $2 billion seed round in July 2025.
The round is not done yet, and that part matters. Neither Thinking Machines Lab nor Accel has confirmed the deal, and a company representative declined to comment, according to the reports. Terms could still shift before the money lands. But multiple sources familiar with the matter told Business Insider the round is close, and the details have since been carried by Dealroom, SiliconANGLE and Tech Funding News.
If it closes, the startup will have raised about $7 billion in disclosed funding in under two years, not counting an undisclosed Nvidia investment from March. Nvidia is separately in talks to invest about $2.5 billion, according to earlier reporting by The Information. Accel is a familiar face at the table: the firm backed the seed round too, alongside Andreessen Horowitz, Nvidia, AMD, ServiceNow, Cisco and Jane Street.
It’s a comedown and a vote of confidence at the same time.
Murati had chased a $50 billion valuation in talks late last year, and those talks fell apart. Settling for $40 billion now still puts her 20-month-old company among the most richly valued AI startups on the planet, and it does so in a week when investors have been repricing the whole sector. Bloomberg reported Friday that Anthropic’s expected IPO valuation has slid to between $1.2 trillion and $1.3 trillion, down from roughly $2 trillion in early October.
What the $5 billion Thinking Machines Lab funding round buys
Thinking Machines Lab does not sell a chatbot. Its first product is Tinker, a system that lets organizations fine-tune large language models on their own data, charging usage fees on the computing involved. It’s plumbing for the AI boom rather than a consumer brand, and the bet behind the valuation is that fine-tuning becomes a standard line item for companies that want models shaped to their own work.
Revenue is still small next to the price tag. A source told TechCrunch in September that the company’s annual revenue had passed $100 million. At a $40 billion pre-money valuation, that implies a multiple most public software companies would never command. Investors are paying for the team and the trajectory, not the current books.
The lab gave them something fresh to point at this week. Inkling 2 Small, its second-generation model, debuted on November 5. It’s a mixture-of-experts model with 594 billion total parameters and 17 billion active per token, and the lab says it improves on coding, vision, knowledge work and reasoning. The model launched on Tinker first, and the lab says it intends to publish the full weights “under an Apache 2.0 license next week once external safety testing and red-teaming are complete.”
That open-weights promise is the part to watch. Most frontier labs keep their best models behind an API. Publishing 594-billion-parameter weights, even a smaller variant, hands researchers and rivals something they can run, study and build on. It also puts pressure on the lab’s own story: if the weights land next week as promised, the quality of Inkling 2 Small gets judged in the open, not on a benchmark slide.
A lab that keeps losing co-founders
Money is not the company’s only headline this year. Three of Murati’s co-founders left between October 2025 and January 2026 for Meta and OpenAI, according to Tech Funding News, taking about a third of the founding team with them. Rivals have been offering large pay packages to poach top researchers, and a startup that has raised billions is still a small shop next to the giants doing the hiring.
That churn makes the Accel round read differently. A $5 billion check from a lead investor that already knows the company is a signal that the departures have not scared off the people with the most information. It’s also a war chest: at this valuation, the lab can afford to pay up to keep the researchers it still has, and to buy the computing its models need.
Murati knows the other side of this market as well as anyone. She ran technology at OpenAI through the ChatGPT years, then left to start her own lab in February 2025 and raised $2 billion before shipping a product. The seed round valued the company above $10 billion on the strength of her name and her team alone. Now the company has a product, a model and reported revenue, and investors are pricing all three.
Why this matters
Step back and the pattern is hard to miss. Even as public markets punish AI stocks, private money keeps flowing to the labs at the top of the field. Fal raised $1.3 billion at a $16 billion valuation earlier this week. Anthropic’s IPO expectations fell, but only to a level that would still rank among the largest tech listings ever. The correction, such as it is, has hit share prices and paper valuations, not the checks going to frontier labs.
Thinking Machines Lab sits in the middle of that tension. Its valuation has more than tripled in 16 months, its revenue is barely past $100 million a year, and its founding team has thinned. Any one of those facts would sink a normal startup’s pitch. Together, they describe a market that still believes the labs building the models will capture most of the value, and is willing to pay a premium to own a piece of the ones run by people who have done it before.
The round has not closed, and the lab has not commented. If the money lands as reported, Murati will have about $7 billion in disclosed funding and a new model to defend in the open. If it slips, the $40 billion figure becomes another abandoned target, like the $50 billion one before it. Either way, the answer comes soon: the round is expected to close within days.
Frequently asked questions
How much is Thinking Machines Lab raising?
Thinking Machines Lab is set to close a $5 billion funding round led by Accel at a $40 billion pre-money valuation, according to Business Insider. The round has not closed yet, so the terms could still change.
Who founded Thinking Machines Lab?
Mira Murati, the former chief technology officer of OpenAI, founded Thinking Machines Lab in San Francisco in February 2025.
What is Inkling 2 Small?
Inkling 2 Small is Thinking Machines Lab’s new 594-billion-parameter mixture-of-experts model, with 17 billion parameters active per token. It debuted on November 5, and the lab plans to release its weights under an Apache 2.0 license next week.
What does Thinking Machines Lab sell?
Its first product is Tinker, a system that lets organizations fine-tune large language models on their own data, charging usage fees on the computing involved.
Sources: Business Insider, Dealroom, SiliconANGLE, TechCrunch, The Information, Bloomberg.