LONDON, August 20, 2026 – Proskauer advised Atomico on the AI aspects of its $100 million seed investment in Callosum, a company building the layer that makes AI compute work. Atomico is leading the financing, alongside Plural, DCVC, the UK Sovereign AI Fund and other investors. The round is one of the largest seed rounds ever raised by a European company.
Co-founded by Danyal Akarca and Jascha Achterberg, Callosum is developing technology that matches AI workloads with the models and chips best suited to perform them. Its platform is designed to enable AI applications to operate across a growing range of model providers and computing hardware, optimising workloads according to cost, speed and energy requirements.
Proskauer was engaged as Atomico’s specialist AI counsel due to the technically complex nature of Callosum’s technology. Acting alongside main deal counsel, Proskauer’s team advised on AI matters central to the investment, including the technical architecture and operation of Callosum’s offerings; data governance; ownership and protection of proprietary technology; open-source software management; customer and supplier arrangements; information security; and AI, data protection and related regulatory compliance.
The mandate builds on Proskauer’s track record advising leading investors and AI companies on AI investments, model development and deployment, product launches, vendor contracting and procurement, regulatory strategy and risk management.
The Proskauer team was led by London-based partner Oliver Howley and New York associate Peter Cramer (TMT/AI), with support from special counsel Kelly McMullon (Data Protection) and associates Caroline Rimmer, Meredith Lipson and Julia Jansen (TMT/AI).
About Proskauer
Proskauer is an elite global law firm with more than 900 lawyers in key financial centers in the United States, Europe, South America, and Asia. Our clients include many of the world’s leading businesses, including asset managers, banks, listed corporations, and private companies.
Our Technology, Media & Telecommunications (TMT) Group serves as commercial and strategic advisors on AI model development, product launches, procurement and integration projects, regulatory compliance, risk management, and investment transactions involving AI technologies. We offer commercial and strategic advice across the full AI lifecycle, from early conceptual development and deployment through ongoing operations, compliance assessments, and complex transactions.