24AUG

Cambridge brain duo raise $100m seed

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16:40UTC

Callosum, founded last year by two Cambridge neuroscientists, took a $100m seed led by Atomico and announced chip partnerships on the same day.

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Key takeaway

Callosum raised $100m at seed on two Cambridge neuroscientists and two chip partnerships.

Callosum, a Cambridge neuroscience startup, raised a $100m seed round led by Atomico on 20 August, with Plural and DCVC participating⁠¹. The company was founded in 2025 by Danyal Akarca and Jascha Achterberg, both neuroscientists at the University of Cambridge, and it announced partnerships with the chipmakers Cerebras and Rebellions alongside the round.

Seed rounds of this size are priced on the founders and the thesis, because there is nothing else yet to price. Callosum works on how AI systems use models and hardware together, which is why the two partnerships matter more than the usual logo slide: Cerebras builds wafer-scale accelerators and Rebellions builds inference silicon, and neither signs a research partnership with a company whose approach it cannot run on its own hardware.

Atomico led the round in a fortnight when the rest of the UK funding tail thinned sharply, so a single Cambridge seed accounted for most of one week's national total. Cambridge has produced this shape before: CuspAI, founded in 2024 by researchers in the same city, closed a $450m Series B in July on a coalition of 45 partners. Investors writing nine figures into a company founded last year are buying a scarce team rather than a revenue line. What decides whether the price holds is how fast the Cerebras and Rebellions work turns into systems other people can run.

Deep Analysis

In plain English

Callosum is a new company in Cambridge, founded by two neuroscientists, Danyal Akarca and Jascha Achterberg, who study how brains process information and are applying that to building AI systems. The company just raised $100m in its seed round, the very first big round of funding a company gets, led by the venture firm Atomico. A $100m seed round is unusually large; many UK companies do not raise that much money across several funding rounds combined. Callosum also announced partnerships with two chip makers, Cerebras and Rebellions, suggesting its approach to AI needs different computer hardware than the standard approach most AI companies use.

Deep Analysis

Root Causes

Atomico leading a $100m seed, an unusually large first institutional round, reflects a shift in how AI-adjacent deep-tech gets priced: investors increasingly treat the team's technical pedigree, here two Cambridge neuroscientists, as the primary signal at seed stage, because the compute and talent costs of building a credible AI research effort have risen faster than the traditional seed-round size.

Callosum's partnerships with Cerebras and Rebellions, both chip makers rather than customers, also point to a structural cause: neuroscience-inspired AI models often need non-standard hardware, so early capital is being spent partly on hardware access rather than only on headcount.

What could happen next?

Meaning
A $100m seed round for a pre-revenue Cambridge team signals investors are pricing technical pedigree over product-market fit at the earliest funding stage.

Sources:Callosum

Mentions:Callosum →Atomico →Plural →DCVC →Danyal Akarca →Jascha Achterberg →University of Cambridge →CuspAI →London →Cambridge →Google →

First Reported In

Update #14 · UKRI's sponsor department no longer exists

Callosum· 24 Aug 2026

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Causes and effects

This Event

Cambridge brain duo raise $100m seed

A seed round of this size prices a year-old research team as though it were a Series B company, and the chip partnerships show what the money is for.

Led to

UK weekly tech funding falls 72%

Callosum's £73.5m share of a £102.95m week explains most of the reported 72% weekly fall.

Occurred 21 Aug 2026

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Different Perspectives

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Dame Chi Onwurah and the Science, Innovation and Technology Committee

Committee chair Dame Chi Onwurah wrote to government on 7 September asking how Matt Clifford's conflict at ARIA arose and what safeguards protect its governance, and expects a detailed response. Her question has not yet been put to the Sovereign AI Unit, whose own chair sits at a venture capital firm while overseeing state AI equity.

The Entrepreneurs Network

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New Economics Foundation

The New Economics Foundation argues fiscal accounting rules, not political will, cap what Britain's state capital vehicles can do. Matching the KfW and Bpifrance benchmark of 1% of GDP would need the National Wealth Fund to deploy roughly GBP21bn a year by 2028-29, about four times its current capacity.

Competition and Markets Authority

The CMA's 8 September report on public procurement asked whether Britain's roughly GBP400bn state-spending system is built to grow high-potential firms rather than simply widen SME participation. Its Recommendation 5 calls for a dedicated frontier-technology procurement framework, an official acknowledgement that today's design may serve the wrong target.

Highland Europe

Highland Europe, the growth-equity firm behind a €1bn-plus fund, took €65m from the British Business Bank into its Technology Growth Fund VI on 30 July via British Patient Capital. For a Geneva-based growth investor, the Bank's cheque is routine cornerstone capital, unrelated to which Whitehall department currently claims to sponsor UKRI.

Written with AI from Lowdown's published reporting. Not individually reviewed by an editor. Editorial standards.