Ex-Anthropic researchers' Mirendil raises $1B Series A led by Kleiner Perkins and Clearlake

What's the deal? Mirendil, the San Francisco AI lab founded by former Anthropic researchers, has raised a $1 billion Series A co-led by Kleiner Perkins and Clearlake CapitalDealroom has a profile for this one. Try Dealroom →. Battery Ventures, Doerr Capital, Gil & Co, Google, M13, Pear VC and S32 also took part, alongside other new and existing investors. The company did not disclose a valuation; in September, Bloomberg reported Mirendil was in talks to raise up to $1 billion at a $5 billion valuation.

From seed to $1B in five months: Mirendil launched in June with a $200 million seed round led by Andreessen Horowitz and Kleiner Perkins at a valuation of around $1 billion, later joined by Nvidia. The company is led by CEO Behnam Neyshabur, who co-led Google DeepMind's Blueshift team, and CTO Harsh Mehta, who built the first version of Anthropic's internal AI research platform.

What has it built? Mirendil's pitch is that agents doing the hands-on work let tiny teams do frontier AI research. It says one researcher working with agents pretrained Mirendil-Base, a competitive coding model, from scratch in 3.5 months with less than $10 million in compute. It then post-trained that into Fern, a model that holds up to 10 million tokens of context. Lor, now in private beta, runs hundreds of agents writing code and running experiments for days at a time.

Why it matters: A $1 billion Series A is rare even in AI, and it puts Mirendil among the best-funded of the new AI research labs, alongside Safe Superintelligence, Thinking Machines Lab and Recursive Superintelligence. It lands a week before Anthropic, where much of the founding team came from, is set to list on Nasdaq.

Sources: Mirendil via PR Newswire, 12 November
Reuters, 12 November
Axios Pro Rata, 12 November
Bloomberg, 22 September
Mirendil.com, company announcement
PR Newswire, 12 November