Oxford Quantum Circuits (OQC) has raised £260 million ($350m) in an oversubscribed Series C funding round.

The company said it represents the largest fundraise ever completed by a quantum computing company in Europe, reflecting the “growing confidence” in quantum computing.

Led by Bullhound Capital, the round also saw participation from the British Business Bank, Oxford Science Enterprises, and Chevron. OQC said the funding would support its global expansion, including scaling quantum infrastructure and advancing the development of its next-generation systems.

“[The funding] will deepen our research and development efforts, helping us accelerate innovation across both hardware and platform capabilities, while reinforcing our position as a global leader in the quantum computing field,” the company said.

Founded in 2017, OQC spun out of the University of Oxford and develops and operates superconducting quantum computers. It uses its own “Coaxmon” 3D architecture, rather than 2D circuits, to simplify fabrication and improve the coherence of quantum systems.

The company previously raised $40.5 million via a Series A funding round in 2022 and $100m from a Series B round in 2024. To date, OQC has deployed quantum computers in a Cyxtera data center in the UK and a quantum-AI data center run by Digital Realty in New York City.

“This is a coming-of-age moment for British quantum computing. It shows that British companies can play a leading role in a technology that will shape all our futures,” said Gerald Mullally, CEO, OQC. “Globally, it represents a clear shift in the market – from long-term promise to near-term delivery in quantum computing. For OQC, this gives us the capital to scale internationally, advance our technology roadmap, and meet increasing demand from customers seeking secure, scalable access to quantum computing infrastructure.”