Quantum Motion Extends Its $160 Million Series C, Again

Quantum Motion, a UK silicon-chip quantum computing company, added five new investors to its Series C round in a second close announced Sept. 3, the company said in a press release. The company did not disclose how much money the new close added to the $160 million the round raised when DCVC and Kembara led its first close in May, TechFundingNews reported at the time. Quantum Motion was founded by researchers from the University of Oxford and University College London, according to TechFundingNews.

What the September close added, and did not disclose

The new backers are imec.ventures, Lansdowne Partners, Sony Innovation Fund, S3 Ventures and Inkef, joining DCVC and Kembara from the May close, according to Quantum Motion's release and The Quantum Insider. Chief executive James Palles-Dimmock said "silicon technology transformed classical computing and it remains the only platform capable of delivering the density and scale required for practical quantum utility." Neither Quantum Motion nor any of the five new investors put a number on the September tranche or a fresh valuation on the combined round.

imec.ventures head Olivier Rousseaux said the firm invested "because of its demonstrated ability to execute and scale where others face bottlenecks," and S3 Ventures general partner Aaron Perman said Quantum Motion's progress "proves that silicon spin is the most scalable, cost-effective path to practical quantum utility." Lansdowne Partners senior partner Peter Davies cited "the milestones achieved across performance and manufacturing."

The silicon bet, in numbers

Quantum Motion builds qubits, the basic unit of quantum information, from electron spins inside silicon transistors made on standard CMOS production lines, the same manufacturing process used for ordinary computer chips. The company's own release claims that approach costs single-digit millions of dollars to build at scale, against more than $100 million for competing qubit architectures, and that it needs 100 times less physical space and 1,000 times less energy than those alternatives. Those figures are Quantum Motion's own and were not independently verified by any outside benchmark in the material The Terminal reviewed.

Claim	Silicon spin qubits (Quantum Motion)	Alternative architectures
Build cost at scale	Single-digit millions of dollars	More than $100 million
Physical footprint	Baseline	100 times larger
Energy use	Baseline	1,000 times higher

Where the chips have already run

Quantum Motion said it deployed a full-stack silicon CMOS quantum system at the UK's National Quantum Computing Centre, a claim Sony Innovation Fund managing director Antonio Avitabile cited directly when he said the company had "consistently executed against an ambitious roadmap." The company has also opened a laboratory in Maryland and is participating in Stage B of the U.S. Defense Advanced Research Projects Agency's Quantum Benchmarking Initiative, according to its release.

Those are the milestones the new investors are pointing to rather than a dollar figure. Inkef general partner Frank Lansink said "their recent milestones prove that the future of quantum is being built on standard silicon," language that reads as a bet on Quantum Motion's roadmap rather than a verified performance result against a rival machine.

The round adds to a run of large, hardware-heavy deep-tech raises, including Cornelis Networks' $205 million funding for data-center networking chips and Ayar Labs' $5 billion secondary sale in optical interconnects, both of which, like Quantum Motion, sell to the same data-center buyers rather than to consumers.

What Quantum Motion has not said

Quantum Motion has not said what its silicon system at the National Quantum Computing Centre can actually compute, how many qubits it runs, or what stage of DARPA's benchmarking program it expects to clear next. Until the company or DARPA publishes a result, the case for silicon spin over rival qubit designs rests on the investors' language rather than a published number.