C
Callosum
Software that unifies heterogeneous AI models and chips
About Callosum
Callosum is a London AI infrastructure company building software that unifies heterogeneous models and chips—orchestrating AI workloads across specialised silicon rather than scaling a single model on uniform hardware. Co-founded by neuroscientists Dr. Danyal Akarca and Dr. Jascha Achterberg (Cambridge PhDs; experience spanning Google DeepMind and Intel), Callosum delivers Tailored Inference APIs that route tasks to the best model–chip combination under cost, energy and latency constraints, with compute partnerships including Cerebras and Rebellions. After a $10.25 million Plural-led pre-seed with ARIA support in February 2026, Callosum raised a $100 million (€85.4 million) Seed in August 2026 led by Atomico, with significant participation from Plural, DCVC and the UK Sovereign AI Fund—the fund’s first investment—and was named in the UK’s £1.1 billion AI hardware plan.
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Sources: Callosum (20 Aug 2026); EU-Startups (20 Aug 2026).
At a glance
- Status
- Operational
- Founded
- 2025
- Headquarters
- London, United Kingdom
- Employees
- 22
- Open positions
- 9
- Dealroom signal
- 85.4/100
- Industry
- Semiconductors
- Sector
- AI, Core AI, Future of Computing, Chips and Processors, MLops, AI Computing Infrastructure, DT and LS, out of stealth, uk is8 digital and technologies, science-based
- Technology
- Artificial Intelligence, Deep Tech
- Business model
- SaaS
- Client focus
- b2b
Knowledge graph
More headlines
Funding history
Company financing events and reported valuations.
| Deal type | Date | Amount | Valuation | Investors | Source |
|---|---|---|---|---|---|
| EARLY VCOther financing | Apr 2026 | $0 | — | UK Sovereign AI | ↗ |
| GRANTOther financing | Feb 2026 | $0 | — | ARIA | ↗ |
Growth signals
Latest recorded traffic for Callosum is 5.3K monthly website visits, down 40.4% over the last three months.
Open positions
Similar companies
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Investments and acquisitions
Recent portfolio relationships for companies that also act as investors or acquirers.
Investors
From Dealroom's funding and investor records, grouped by the round each investor first entered.
Seed7 investors entered at this stage
ARIA
Plural
Entrepreneurs First
Stan Boland
Charlie Songhurst
John Lazar
Dominic Jacquesson
Series A1 investor entered at this stage
UK Sovereign AI
Other known investors1 additional known investor
Source: Dealroom Talent Intelligence.
Global footprint
team presence
Market sentiment
An AI-synthesised read of the highest-engagement posts about Callosum on X, ranked by likes and reposts, corporate channels excluded.
Reading the room on X — pulling top posts and synthesizing themes…
Source: X recent search ranked by engagement (likes + retweets) · Synthesis by Claude · Cached for 1 hour
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