Quantum computing stocks, part by part

Named for their roles. They have no ticker, quote or company page, and they are not counted among the 65 public companies.

• SkyWater Technology Subsidiary of IonQ (IONQ)

  U.S. foundry that makes D-Wave’s superconducting QPU wafers under a semiconductor line operation agreement (D-Wave FY2025 10-K); its own FY2025 10-K says it supports superconducting, photonic and spin-based quantum customers. IonQ completed its acquisition on July 31, 2026 ($15.00 in cash plus 0.4883 IonQ shares per share) and SKYT was delisted; the role is mapped to IONQ.

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• QuantWare Not publicly listed

  Delft-based maker of superconducting QPUs (A-Line and D-Line) that also sells foundry services, VIO chiplet-packaging services and a Crescendo TWPA; its news page reports a $178M raise and Intel backing (Intel is an investor, not a stand-in).

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• Plassys Not publicly listed

  French maker of electron-beam evaporation systems; a University of Chicago and Stanford qubit recipe loads sapphire wafers into a Plassys MEB550S evaporator.

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• Raith Not publicly listed

  German e-beam lithography maker; a University of Chicago circuit-QED paper defines its Josephson-junction masks with a Raith EBPG5000 Plus writer.

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• AJA International Not publicly listed

  U.S. deposition-system maker; QuTech’s 2026 flip-chip qubit recipe deposits gold for its indium bumps in an AJA International evaporator.

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• Indium Corporation Not publicly listed

  U.S. indium supplier; QuTech’s 2026 flip-chip qubits use its indium sulfamate plating bath and pure indium anode for electroplated bumps.

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• Amuneal Not publicly listed

  U.S. magnetic-shield fabricator that builds cryogenic shielding for cryostats, dewars, SQUIDs and SRF cavities.

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• Magnetic Shields Ltd Not publicly listed

  UK magnetic-shielding maker that markets cryogenic and quantum-technology shielding, including for quantum computing.

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• Orano Not publicly listed

  Unlisted French nuclear fuel-cycle group that Quobly names, with Air Liquide and Soitec, as a strategic partner in its silicon-28 value chain; its role is not detailed.

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• Topsil GlobalWafers A/S Subsidiary of GlobalWafers (6488.TWO)

  Danish float-zone silicon maker in the GlobalWafers group (acquired July 1, 2016); QuTech’s 2026 flip-chip qubits used its >20 kΩ·cm wafers. GlobalWafers’ own listing covers the role.

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• ULVAC CRYOGENICS Subsidiary of ULVAC (6728.T) and Edwards (Atlas Copco) as a 50:50 joint venture

  Co-developer of ULVAC’s quantum dilution refrigerator; a 50:50 joint venture of ULVAC, Inc. and Edwards Vacuum LLC (Atlas Copco Group) per its company outline, so it is not a wholly owned subsidiary of either. ULVAC’s own listing covers the role.

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• Quobly Not publicly listed

  French silicon spin-qubit maker whose QSOI chips are fabricated in STMicroelectronics’ 300 mm Crolles fab on Soitec 28Si FD-SOI wafers; raised a €115M Series A in June 2026 co-led by Bpifrance, SEALSQ and STMicroelectronics.

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• Qolab Not publicly listed

  Superconducting-qubit startup co-founded by John Martinis that leads hardware for an HPE-co-led DARPA Quantum Benchmarking Initiative consortium, with Applied Materials for materials and wafer-level fabrication.

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• Bluefors Not publicly listed

  Finnish dilution-refrigerator maker (XLDsl, LD and the KIDE platform for more than 1,000 qubits) that calls itself the world leader in cryogenic cooling systems for quantum technology. It completed its acquisition of US pulse-tube maker Cryomech on Mar 28, 2023, and in Sept 2025 agreed to purchase up to 10,000 liters a year of lunar helium-3 from Interlune for delivery in 2028–2037.

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• Cryomech Subsidiary of Bluefors (private)

  Syracuse, New York maker of PT-series pulse-tube cryocoolers (PT205–PT820), Gifford-McMahon cryocoolers, helium compressors and helium liquefiers; its PT310-RM is integrated into Bluefors dilution refrigerators.

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• Quantum Design (Quantum Design Oxford) Not publicly listed

  Privately held San Diego instrument maker that completed its acquisition of Oxford Instruments’ NanoScience division on Jan 2, 2026; the business now trades as Quantum Design Oxford and sells Proteox dilution refrigerators (ProteoxLX: below 7 mK, over 25 µW at 20 mK, 530 mm plate).

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• Maybell Quantum Not publicly listed

  US maker of compact dilution refrigerators (Fast Fridge, Big Fridge) and cryogenic wiring for the quantum industry.

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• Leiden Cryogenics Not publicly listed

  Dutch maker of dry dilution refrigerators since 1992 (CF-CS110, CF-CS110-XXL, QUPER).

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• Zero Point Cryogenics Not publicly listed

  Canadian maker of dilution refrigerators for quantum technology; it announced QPU-ready systems with Quantum Machines.

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• ICEoxford Not publicly listed

  UK maker of dry cryostats and dilution refrigerators, listing quantum computing among its applications.

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• Lake Shore Cryotronics Subsidiary of DwyerOmega (private)

  US maker of cryogenic thermometers (Cernox, Rox), AC resistance bridges, temperature controllers, Janis cryostats and recirculating chillers; now a DwyerOmega brand.

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• kiutra Not publicly listed

  Munich maker of adiabatic demagnetization (ADR) cryostats for quantum technologies, developing a helium-3-free millikelvin cooling platform.

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• Cryoconcept Subsidiary of Air Liquide (AI.PA)

  French dilution-refrigerator maker (below 10 mK) spun off from CEA in 2000; Air Liquide acquired 80% in Sept 2020. Its website did not resolve on 2026-09-28, so its current range was not verified.

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• Interlune Not publicly listed

  Privately funded Seattle company planning to harvest helium-3 from the Moon; Bluefors agreed to purchase up to 10,000 liters a year for delivery in 2028–2037.

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• Delft Circuits Not publicly listed

  Dutch maker of Cri/oFlex superconducting flex cables (eight channels per 0.3 mm flex, up to 256 per loader, with built-in attenuators, low-pass and IR filters), offered with Bluefors refrigerators; its extended Series A brought total funding to €15 million (March 2026).

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• COAX CO., LTD. Not publicly listed

  Yokohama maker (founded 1974) of cryogenic and superconducting semi-rigid coax in CuNi, stainless steel, BeCu and NbTi for low-temperature use; since June 1, 2026 a Japanese distributor handles its international sales.

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• TOTOKU Subsidiary of TTC Holdings (Carlyle-managed fund)

  Japanese cable maker (formerly Tokyo Special Electric Wire) whose semi-rigid cables in stainless steel, CuNi, silver-plated CuNi and NbTi are marketed for cryogenic quantum computers; delisted on January 25, 2023 after a tender offer by TTC Holdings, owned by a Carlyle-managed fund, into which Furukawa Electric sold its 57.05% stake.

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• CryoCoax (Intelliconnect) Subsidiary of Intelliconnect (Trexon group, not listed)

  UK cryogenic RF brand, ‘a division of Intelliconnect’, selling cryogenic and superconducting cable assemblies, flexible cryogenic cables, connectors and attenuators for quantum computing; Intelliconnect presents itself as part of the Trexon family of companies.

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• Radiall Not publicly listed

  French connector maker founded in 1952 by the Gattaz brothers; its quantum range covers cryogenic cable assemblies, non-magnetic connectors, attenuators and Cryonium switches for thermalization to tens of millikelvin. RA.PA returns no quote.

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• Rosenberger Not publicly listed

  German connector maker whose non-magnetic SMP connectors have the widest use in Japanese research institutions, per the AIST–RIKEN–Fujitsu–NEC roadmap; it lists cryogenic and quantum technology among its industrial markets.

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• Fischer Connectors Not publicly listed

  Swiss connector maker whose connectors are often used for DC lines and hermetic seals on the vacuum can, per the AIST–RIKEN–Fujitsu–NEC roadmap.

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• XMA Corporation Subsidiary of Amphenol (APH)

  New Hampshire maker of cryogenic attenuators, terminations, DC blocks and IR filters for quantum computing; an Amphenol subsidiary since 2023, mapped through APH.

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• Narda-MITEQ Subsidiary of Amphenol (APH)

  Hauppauge, New York maker of CLNA cryogenic low-noise amplifiers qualified to 4 K and of room-temperature LNAs; acquired by Amphenol in May 2025 and mapped through APH.

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• Hirose SER Subsidiary of Hirose Electric (6806.T)

  Tokyo maker of NbTi multi-channel coax connector cables for quantum computers (DC to 40 GHz); a Hirose Electric group company since 2025, mapped through 6806.T.

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• API Technologies Not publicly listed

  US RF component maker whose cryogenic SMA attenuators are widely used, and whose bias tees have been used, in Japanese quantum research, per the AIST–RIKEN–Fujitsu–NEC roadmap.

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• Quantum Microwave Not publicly listed

  US maker and distributor of cryogenic microwave components (attenuators, IR and band-pass filters, bias tees) that sells Low Noise Factory amplifiers in the Americas, Silent Waves TWPAs in North America and Raytheon BBN’s cryogenic products worldwide.

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• Mini-Circuits Not publicly listed

  US RF component maker whose attenuators, band-pass filters and bias tees are common in qubit wiring and readout, per the AIST–RIKEN–Fujitsu–NEC roadmap.

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• RLC Electronics Not publicly listed

  US RF filter maker named among the main low- and high-pass filter suppliers for qubit lines in the AIST–RIKEN–Fujitsu–NEC roadmap.

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• Marki Microwave Not publicly listed

  US RF component maker whose compact bias tees were confirmed to work at cryogenic temperatures, per the AIST–RIKEN–Fujitsu–NEC roadmap.

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• Low Noise Factory Not publicly listed

  Gothenburg, Sweden maker of cryogenic HEMT low-noise amplifiers, isolators and circulators with a high share in superconducting-qubit research (AIST roadmap); it takes part in the EU OpenSuperQ project to develop cryogenic microwave components for control and readout. No acquisition was found.

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• Cosmic Microwave Technology Not publicly listed

  California maker of cryogenic low-noise amplifiers built to Caltech designs licensed by Sander Weinreb, used for radio astronomy and quantum computing.

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• QuinStar Technology Not publicly listed

  Torrance, California maker of cryogenic circulators, isolators and arrays that work down to the millikelvin range for applications including quantum computing; ETH Zurich’s 100-qubit-scale setup uses a QuinStar circulator.

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• Nihon Tsushinki Not publicly listed

  Kanagawa maker (founded 1949) of 4 K isolators and HEMT amplifiers; NEDO selected its project on highly integrated domestic cryogenic low-noise amplifiers for quantum computers on July 30, 2026.

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• Silent Waves Not publicly listed

  Grenoble maker of traveling-wave parametric amplifiers for multiplexed qubit readout (Argo, Carthago and the Zephyr, launched March 13, 2026).

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• SCALINQ Not publicly listed

  Gothenburg company selling the QET Vidar traveling-wave parametric amplifier (AIST roadmap).

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• VASTA Not publicly listed

  Singapore company selling a 5.5–7 GHz traveling-wave parametric amplifier (AIST roadmap).

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• B&Z Technologies Not publicly listed

  US maker of room-temperature low-noise amplifiers that the AIST–RIKEN–Fujitsu–NEC roadmap calls relatively popular for qubit readout.

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• Qblox Not publicly listed

  Dutch maker of modular qubit control and readout electronics (QCM and QRM modules); listed here for completeness, as its role sits in the control sector.

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• Quantum Machines Not publicly listed

  Quantum control system builder named by NVIDIA among NVQLink partners and a founding member of the HPE-coordinated Quantum Scaling Alliance for hybrid quantum-classical control. AMD quotes its COO saying AMD FPGAs give it real-time quantum control performance.

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• Zurich Instruments Subsidiary of Rohde & Schwarz (private)

  Swiss maker of the QCCS quantum control system (SHFQA+ analyzers, SHFQC qubit controllers, SHFSG+ signal generators, HDAWG AWGs, PQSC system controllers), built on AMD RFSoCs and Versal and Virtex devices. It is part of the privately held Rohde & Schwarz, so neither offers a listed route to its economics.

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• QuEL Not publicly listed

  QuEL, Inc. (Hachioji, Tokyo) commercializes the University of Osaka’s QuBE controller, which uses Analog Devices AD9082 converters and ADRF6780 mixers, Texas Instruments LMX2594 synthesizers and AMD Alveo FPGA boards and was validated on a 64-qubit RIKEN-designed transmon chip (June 2026).

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• Riverlane Not publicly listed

  Cambridge, UK, developer of the Deltaflow 2 error-correction system with decoders that correct millions of errors per second, integrated with Qblox control hardware (Mar 17, 2026) and a founding member of the HPE-coordinated Quantum Scaling Alliance; it has raised over $120 million privately.

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• Q-CTRL Not publicly listed

  Quantum control software maker: Boulder Opal toolkits to design, automate and scale quantum hardware and controls, and Fire Opal, which reduces errors on cloud quantum computers; NVIDIA lists it among users of its Ising calibration model. Software, not control hardware.

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• Intermodulation Products Not publicly listed

  Maker of Presto, a microwave arbitrary waveform generator and analyser it markets for superconducting quantum circuit research, plus RFSoC add-ons.

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• Spectrum Instrumentation Not publicly listed

  Maker of AWG and digitizer cards it markets for qubit research on its quantum computing application page.

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• Swagelok Not publicly listed

  Bluefors standardized on Swagelok tube fittings, and uses Swagelok high-pressure panels, wherever pure helium runs at high pressure in its dilution refrigerators; Swagelok also keeps reserved inventory for Bluefors (Bluefors, Sept 15, 2020).

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• Busch Group Not publicly listed

  Family-owned vacuum group whose brands are Pfeiffer Vacuum+Fab Solutions and Busch Vacuum Solutions; its subsidiary Pangea GmbH controls listed Pfeiffer Vacuum Technology AG under a domination and profit-and-loss transfer agreement registered on May 16, 2023.

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• Laurentis Energy Partners Subsidiary of Ontario Power Generation

  Commercial subsidiary of Ontario Power Generation that has extracted helium-3 from tritium stored at the Darlington CANDU station since November 2021 and distributes it through Air Liquide under a long-term agreement (December 7, 2021).

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• SEEQC IPO application filed · not listed

  U.S. maker of superconducting single-flux-quantum (SFQ) digital control and readout chips with its own superconducting foundry. Its SPAC merger with Allegro Merger Corp. was terminated on Aug 25, 2026; it has applied to list on the Nasdaq Global Market as ‘SEQC’ through an IPO (S-1/A, Sept 22, 2026), not priced as of 2026-09-28.

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• Origin Quantum (本源量子) Not publicly listed

  Hefei superconducting quantum-computer maker (Wukong series; the 180-qubit Wukong-180 in 2026) that says it develops chips, measurement and control, cryogenic support and operating software in house. Registered for STAR Market IPO tutoring in Sept 2025 and raised a Pre-IPO round in June 2026; no accepted IPO application was verified.

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• SpinQ (量旋科技) Not publicly listed

  Shenzhen maker of superconducting quantum computers and NMR teaching machines; raised a RMB 600 million C+ round and started a Pre-IPO round (April 2026). No exchange filing was found.

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• PsiQuantum Not publicly listed

  Photonic quantum-computer developer in the final phase of DARPA’s US2QC program; private.

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• QuEra Computing Not publicly listed

  Neutral-atom maker (Boston) selected for DARPA QBI Stage B; a Google portfolio company (Google, Mar 24, 2026). Private.

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• Atom Computing Not publicly listed

  Neutral-atom maker (Boulder) selected for DARPA QBI Stage B; private.

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• Diraq Not publicly listed

  Silicon CMOS spin-qubit developer (Sydney) selected for DARPA QBI Stage B; private.

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• Nord Quantique Not publicly listed

  Superconducting bosonic-code developer (Sherbrooke) selected for DARPA QBI Stage B; private.

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• Photonic Inc. Not publicly listed

  Optically linked silicon spin-qubit developer (Vancouver) selected for DARPA QBI Stage B; private.

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• Quantum Motion Not publicly listed

  MOS silicon spin-qubit developer (London) selected for DARPA QBI Stage B; private.

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• Silicon Quantum Computing Not publicly listed

  Precision atom qubits in silicon (Sydney), selected for DARPA QBI Stage B; private.

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• Alice & Bob Not publicly listed

  Superconducting cat-qubit developer named by Horizon Quantum as a hardware partner; private.

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• Oxford Quantum Circuits Not publicly listed

  Superconducting quantum-computer maker named by Horizon Quantum as a hardware partner; private.

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• OptQC Not publicly listed

  Tokyo optical quantum-computer start-up; NTT plans to invest under an Aug 3, 2026 alliance, and its first machine, MoQuren, runs at AIST’s G-QuAT. Private.

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• Oxford Ionics Subsidiary of IonQ (IONQ)

  Trapped-ion developer with electronic qubit control on chips, acquired by IonQ on Sept 16, 2025.

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• Quantum Circuits Subsidiary of D-Wave Quantum (QBTS)

  Superconducting dual-rail qubit developer (New Haven) acquired by D-Wave on Jan 20, 2026.

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• Anderon Subsidiary of IBM (IBM)

  IBM’s 300 mm pure-play quantum wafer foundry in Albany for superconducting qubit arrays, quantum I/O and readout-chain components; finalized a $1 billion CHIPS award on Sept 16, 2026.

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• HRL Laboratories Subsidiary of Boeing and General Motors (joint)

  Research lab jointly owned by Boeing and General Motors with silicon spin-qubit, cryogenics and control-electronics work; IBM agreed to acquire it (July 23, 2026), with closing expected by the end of Q3 2026.

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Guides and component studies