Quantum computing is a bleeding-edge field of technology that harnesses the complex laws of quantum mechanics to process information in a completely different way to traditional computing. Quantum computing stocks are those which direct a significant portion of their business into the research and development of this technology.

There are three key principles to consider when it comes to understanding quantum computing’s potential.

First, unlike classical computers, which use bits as the basic unit of information (each bit representing either a 0 or a 1) quantum computers use quantum bits, or qubits, which can represent 0, 1 or both at the same time through a property called superposition.

This means that a quantum computer can process a massive number of possibilities simultaneously, which could exponentially speed-up certain types of computing problems — therefore offering a significant commercial advantage.

Second, quantum computing works because of quantum entanglement, a phenomenon where the state of one qubit is directly related to the state of another, even if they are physically separated.

This link allows quantum computers to co-ordinate multiple qubits in complex calculations that current computers would find incredibly time consuming or even impossible.

Third is the principle of quantum interference, which enables quantum algorithms to increase the probability of correct outcomes while cancelling out the wrong ones. Together, these three principles may allow for a new age of compute.

For example, in cryptography, quantum computers could break current encryption methods by factoring large numbers much more efficiently than classical computers. In medicine, quantum systems could simulate complex molecular interactions at the atomic level, speeding up novel drug discovery and improving the chances of success in clinical trials.

In finance and logistics, quantum algorithms might optimise systems with too many variables for current computers to assess accurately, like supply chain routes or investing algorithms. Arguably, almost every sector will be affected to some degree.

However, it’s still early days. Current machines are primarily noisy intermediate-scale quantum (NISQ) devices. These systems are more like science experiments than usable tech, as they are prone to mistakes, sensitive to environmental interference and limited in the number of qubits they can use. They must also be kept at near-absolute-zero temperatures and shielded from electromagnetic noise. And then there’s the quantum error correction issue to consider, which is essential for scaling up.

Despite these challenges, progress continues. It’s worth noting that the World Wide Web was only launched in 1989. Progress and adoption in tech can be very slow, then fast. Governments, corporations and universities across the world are all investing heavily in quantum research, and while mainstream, large-scale quantum computing may still be years (or even decades) away, many experts believe it could eventually change the world.

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Best large-cap quantum computing stocks to watch

As the cost of researching quantum computing is prohibitive, with the pay-off perhaps a decade or more away, the majority of the investment is being conducted by large-cap US tech stocks with the requisite financial firepower.

It’s also worth noting that these stocks have the benefit of not relying solely on the success of their quantum experiments, which mitigates the risk involved. And interestingly, each appears to be focusing on a different quantum strategy, rather than directly competing.

The following stocks are ordered by market capitalisation.

Nvidia

Nvidia remains the most valuable company in the world by market capitalisation. Known for its graphics processing units (GPUs), the company is also investing heavily in quantum computing through high-performance GPU simulation and hybrid quantum-classical systems.

Its CUDA Quantum platform allows developers to simulate quantum circuits on classical Nvidia GPUs, allowing researchers to test algorithms at scale before running them on real quantum hardware. Nvidia is also partnering with smaller specialists including IonQ to bridge the performance gap between quantum and classical systems.

Nvidia's DGX Quantum, co-developed with Israeli quantum company Classiq, links Nvidia's Grace Hopper Superchip with quantum processors — and is arguably at the cutting-edge of current technological possibility. By focusing on the ecosystem rather than building quantum hardware itself, Nvidia is once again positioning itself in a unique position for the coming revolution.

Microsoft

Microsoft's approach centres on a full-stack, hardware-agnostic platform called Azure Quantum. It offers access to quantum hardware from partners including IonQ, Quantinuum, Rigetti and others, making it a leading multi-vendor cloud ecosystem.

Microsoft is also developing its own topological qubit, a more stable and scalable quantum bit based on Majorana particles. Though in early development, this tech could revolutionise quantum hardware due to its superior error resistance.

Azure Quantum supports multiple quantum programming languages, including Q# and Qiskit, and can integrate with classical HPC systems for hybrid workloads. Microsoft is also working on cryogenic control systems and other quantum error correction techniques, targeting fault-tolerant quantum computing.

In addition, the titan owns the Azure Quantum Resource Estimator, which helps researchers analyse the physical requirements of running real-world algorithms on future fault-tolerant quantum computers.

Microsoft is focusing on long-term fault tolerance, positioning itself for breakthroughs in this specific segment of the market.

Amazon 

Amazon's quantum computing R&D is held within its AWS Braket segment as part of Amazon Web Services. Braket provides cloud access to multiple quantum hardware types, including gate-based, annealing and ion-trap systems from providers like IonQ, Rigetti and D-Wave.

This platform is designed to democratise access to quantum technology by supporting a wide range of development tools and hybrid quantum-classical workflows. Amazon has also built the AWS Centre for Quantum Computing at Caltech, where it conducts research into fault-tolerant quantum architectures using superconducting qubits.

Amazon’s strategy is to be hardware-agnostic, meaning it may be able (in time) to support the entire quantum ecosystem, while continuing to research scalable qubit designs and quantum networking.

Meanwhile, its PennyLane integration and support for cross-platform development is encouraging rapid prototyping of quantum algorithms in areas like logistics, financial modelling and machine learning. While Amazon doesn’t produce its own quantum processors, this approach positions it as an infrastructure layer for commercial quantum computing, akin to its dominance in cloud computing. 

Alphabet

Alphabet's quantum computing work is carried out through subsidiary Google Quantum AI. Back in 2019, Google claimed ‘quantum supremacy’ with its 53-qubit Sycamore processor, solving a problem in 200 seconds that would take the best supercomputers 10,000 years (though this claim remains debated).

Google is now pursuing quantum error correction and fault-tolerant computing with its second-generation processors. It’s aiming to build a million-physical-qubit system with high fidelity error-corrected logical qubits by the early 2030s — potentially the ‘Holy Grail’ of quantum.

Google’s also maintains its open-source Cirq library, allowing developers to build and simulate quantum circuits. Uniquely, Google maintains both experimental hardware labs and in-house chip fabrication facilities, making it committed to long-term, scalable quantum computing with real-world applications.

IBM

IBM is one of the earliest leaders in quantum computing. Its Quantum division offers cloud-based quantum access through the IBM Quantum Experience, which supports over 20 quantum systems globally.

IBM uses superconducting qubits and has consistently published a detailed hardware roadmap, including goals for a 1,121-qubit chip and modular quantum systems with quantum interconnects.

Further, IBM’s Qiskit platform, an open-source quantum SDK, has arguably become a standard in the industry.

IBM has also led in benchmarking quantum performance with metrics like Quantum Volume and CLOPS (circuit layer operations per second). Its Quantum Safe tech works on quantum-resistant encryption, which could well become a cybersecurity necessity in the future post-quantum security era. 

Honeywell

Honeywell generates quantum value through its spinout, Quantinuum, which merged Honeywell Quantum Solutions with Cambridge Quantum.

Honeywell retains a controlling stake and supports the venture through its precision engineering and trapped-ion hardware expertise. For context, trapped-ion qubits are known for their high fidelity and long coherence times, making them ideal for fault-tolerant architectures.

Quantinuum’s H-Series quantum processors are modular, upgradeable and continually improving. The company’s software stack includes TKET, a hardware-agnostic compiler, and InQuanto, a quantum chemistry package. Quantinuum is one of very few quantum companies offering commercial quantum encryption tools, such as quantum key generation and quantum random number generation (QRNG). 

Intel

Intel is pursuing a novel strategy — its qubits are spin qubits in silicon, which are smaller, faster and more compatible with existing chip fabrication than superconducting or ion-trap qubits. The company’s ‘Horse Ridge’ cryogenic control chip operates at extremely low temperatures, reducing the complexity of quantum wiring and enabling better scalability, while its Tunnel Falls chip integrates 12 qubits within a compact silicon structure.

Intel’s plan is to produce millions of qubits using the same lithographic processes as classical chips, unlocking large-scale quantum computing at a relatively low cost — including integration with classical processors, potentially leading to hybrid processors combining quantum and classical logic.

Although still lagging behind in qubit counts compared to rivals, Intel’s investment in R&D and integration with its foundry process may pay off when it comes to realistic scaling.

Growth quantum computing stocks to watch

In addition to the tech titans, here are several smaller growth (though still multi-billion-dollar) pure-play quantum companies to consider. You may notice that many are partnered with the larger titans:

IonQ

IonQ is arguably the market leader in trapped-ion quantum computing, offering high-fidelity qubits that are optically manipulated rather than electrically controlled.

IonQ systems are accessible via the major cloud providers including AWS, Azure and Google Cloud. The company’s architecture is modular, allowing for physical scalability and flexible qubit connectivity, which are significant advantages over fixed-lattice superconducting systems.

IonQ’s latest quantum systems boast high qubit fidelities and are designed to scale linearly without sacrificing performance. The company is also pioneering quantum-as-a-service (QaaS) business models for enterprises in finance, logistics, and pharmaceuticals. The roadmap currently targets systems with 64+ algorithmic qubits by the late 2020s, and ultimately, fault-tolerant quantum systems. 

D-Wave Quantum

D-Wave is uniquely focusing on quantum annealing, a specialised quantum approach to optimisation problems, whereas most other quantum computing companies focus on the more general gate-based quantum computation that aims to handle a broader variety of quantum algorithms.

Its Advantage2 system — which is commercially available via both cloud and on-premises models — features over 5,000 qubits and is tailored for problems in logistics, materials science and AI.

Unlike other firms chasing fault-tolerant gate-based systems, D-Wave’s annealing architecture enables real-world applications today, such as traffic routing, protein folding and supply chain management. The company is also developing a hybrid solver service that combines classical and quantum methods to accelerate results.

Looking ahead, D-Wave’s Advantage3 platform, expected by 2028, will feature further performance upgrades. While some are sceptical about annealing’s long-term potential, D-Wave’s commercially viable systems and steady customer growth make it a serious player in the quantum space, while rivals are sinking capital into advancements that may only be monetizable decades away.

Rigetti Computing

Rigetti is a full-stack quantum computing company that designs and fabricates its own superconducting qubit chips, while also developing the associated software and cloud services.

Its Forest platform, powered by the Quil programming language, allows researchers to build and run quantum algorithms directly on Rigetti’s quantum processors. It recently signed a $500 million strategic partnership with Quanta, and has been steadily progressing its hardware roadmap — with its latest Aspen-M systems integrating modular 80-qubit chips.

Rigetti is focused on achieving quantum advantage in areas including machine learning, optimisation and cryptography. As the company fabricates its chips in-house, it also retains end-to-end control over designs and production.

Quantum Computing

Quantum Computing focuses on photonic quantum computing and hybrid quantum-classical software solutions for enterprise clients.

Unlike superconducting or ion-trap systems, QUBT’s technology uses light particles (photons), which are less prone to decoherence and can operate at room temperature, potentially reducing the costs and complexity of scaling up.

QUBT has dual revenue streams: one from its Arizona-based quantum photonics foundry and another from software licensing for optimisation and security applications. Its core platform supports quantum-enhanced machine learning, combinatorial optimisation and secure communications.

The company is also exploring quantum sensing and quantum secure blockchain products, though remains in the early stages — hence the relatively small market capitalisation.

Quantum computing stocks summed up

• Quantum computing harnesses quantum mechanics principles including superposition, entanglement and interference to solve complex problems much faster than classical computers
• Though still in its early stages with current machines being error-prone and difficult to scale, significant global investment suggests that commercial breakthroughs may emerge in the coming decades
• Major tech giants are pursuing quantum strategies, often via hybrid systems or cloud platforms, while smaller players are building specific quantum technologies such as trapped ions, annealing and photonics
• Investing in quantum computing stocks involves balancing the potential rewards with significant risks including technical hurdles, long timelines and uncertain monetisation pathways