Callosum has raised $100 million in a seed round led by Atomico, with participation from Plural, DCVC, UK Sovereign AI, and angel investors. The round follows a $10.25 million stealth raise in February 2026.
Founded by Cambridge neuroscientists, the startup builds software that lets AI workloads run across different chips and models, challenging the industry's reliance on single-model, single-chip scaling. It has partnered with chipmaker Cerebras, whose CEO said the platform enables ultra-low-latency inference for previously impractical AI systems.