Callosum raises $100M seed
Announced 20 August 2026
◆ The Round
Callosum raised $100M in seed funding, announced on 20 August 2026, led by Atomico, with participation from Plural, UK Sovereign AI Fund, DCVC, U.K. Sovereign AI Fund. The round is tracked live by Fusion42 as part of the Raise fund database and the Scout startup database.
◆ About Callosum
London-based AI infrastructure startup whose platform helps developers route workloads across different AI models and hardware providers to reduce costs. Callosum is based in United Kingdom and currently at seed stage, operating in AI Infrastructure, AI & ML.
◆ Investors
LeadAtomico
ParticipationPlural, UK Sovereign AI Fund, DCVC, U.K. Sovereign AI Fund
◆ Market context
This funding event is a citable node in Fusion42's market graph: it links Callosum's Scout profile to the funds behind the round and to related Wire analysis, and is refreshed from public announcements as the round is confirmed or extended. It is the same live market data Arthur reasons over when benchmarking a founder's own raise against what is closing in the market right now.
◆ Explore the market
◆ FAQ
How much did Callosum raise?
Callosum raised $100M in its seed round, announced 2026-08-20.
Who invested in Callosum's seed round?
The round was led by Atomico, with participation from Plural, UK Sovereign AI Fund, DCVC and U.K. Sovereign AI Fund.
What does Callosum do?
London-based AI infrastructure startup whose platform helps developers route workloads across different AI models and hardware providers to reduce costs.
Verified 20 August 2026 · Sources: public filings