Callosum Raises $100M Seed, One of Europe’s Largest

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Callosum has raised $100 million in a Seed round that ranks among the largest ever closed in Europe. Atomico led the deal, with Plural and DCVC joining and significant backing from the Sovereign AI Fund in the United Kingdom.

The company works from London and builds orchestration software for AI workloads. Its bet is that the next hard problem in AI infrastructure is not finding one superior model or one superior chip, but picking the right combination for each job. The software routes subtasks to whichever chip combination handles them most efficiently.

The name is a reference to the corpus callosum, the dense bundle of neural fibers connecting the two hemispheres of the human brain. It is, in other words, the integration layer between specialized systems, which is what the company is trying to be for computing.

Danyal Akarca and Jascha Achterberg founded the business in 2025, with Akarca as chief executive and Achterberg as chief technology officer. Both are Cambridge University neuroscientists who started working together while doing PhDs in neuroscience, computing and AI. Their research has appeared in Nature journals, and each has held positions at Intel and Google DeepMind.

Being based in the United Kingdom put the company in reach of the national AI fund that helped anchor the round.

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