London-based AI startup Callosum has raised $100 million in a seed funding round led by Atomico, with significant participation from Plural, DCVC, and the UK Sovereign AI Fund, alongside other investors and angel investors. The company previously raised $10.25 million in February 2026, when it emerged from stealth.
- Established in 2025 by Danyal Akarca and Jascha Achterberg, Callosum is developing AI infrastructure based on “heterogeneous intelligence”, an approach that matches different AI models and chips to specific tasks based on cost, speed, and energy efficiency.
- The company argues that real-world problems are complex and require different capabilities rather than relying on a single AI model running on identical hardware.
- Callosum also announced partnerships with next-generation silicon companies, including Rebellions, as well as infrastructure providers and OEMs worldwide. Its flagship partnership with Cerebras focuses on bringing ultra-low-latency, heterogeneous multi-agent AI to customers at scale.
- Its programmable heterogeneity technology breaks AI workloads into individual tasks and orchestrates each one to the model and chip best suited to it, taking into account constraints such as cost, energy, and speed. Meanwhile, its Tailored Inference platform delivers task-specific AI through APIs running across heterogeneous compute.
Details of the deal
- Callosum plans to scale its AI infrastructure, expand partnerships with compute and silicon providers, and accelerate the development of its Tailored Inference platform.
