Best quantum computing stocks to watch

What is quantum computing?

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 understanding quantum computing's potential.

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 a quantum computer can process a massive number of possibilities simultaneously, potentially offering exponential speed advantages for certain types of problems.

Quantum entanglement is a phenomenon where the state of one qubit is directly related to the state of another, even if they are physically separated. This allows quantum computers to co-ordinate multiple qubits in complex calculations that current computers would find incredibly time consuming or even impossible.

The principle of quantum interference 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 computing.

However, it's still early days. Current machines are primarily noisy intermediate-scale quantum (NISQ) devices — more like science experiments than usable technology, prone to mistakes, sensitive to environmental interference and limited in the number of qubits they can use. Despite these challenges, progress continues. 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.

In May 2026, the US Department of Commerce announced a $2 billion funding injection under the CHIPS and Science Act to secure domestic quantum infrastructure — a significant signal of government commitment to the sector. IBM has also targeted a "quantum advantage" demonstration in 2026, and Microsoft's Majorana 1 topological qubit chip, unveiled in February 2025, continues to advance — though the underlying science remains contested.

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Best large-cap quantum computing stocks to watch

As the cost of researching quantum computing is prohibitive — with commercial payoff potentially a decade or more away — the majority of investment is being conducted by large-cap US tech companies with the requisite financial firepower. These stocks have the benefit of not relying solely on the success of their quantum experiments, which mitigates risk considerably. Each appears to be focusing on a different quantum strategy rather than competing directly.

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Nvidia

Nvidia remains one of the world's most valuable companies by market capitalisation. Known for its graphics processing units (GPUs), the company is also investing heavily in quantum computing through its CUDA Quantum platform, which allows developers to simulate quantum circuits on classical Nvidia GPUs — enabling researchers to test algorithms at scale before running them on real quantum hardware. Nvidia's DGX Quantum, co-developed with Israeli quantum company Classiq, links its Grace Hopper Superchip with quantum processors. By focusing on the quantum ecosystem rather than building hardware itself, Nvidia is positioning itself as the enabling infrastructure layer for the coming quantum revolution.

Microsoft

Microsoft's quantum approach centres on a full-stack, hardware-agnostic platform called Azure Quantum, offering access to quantum hardware from partners including IonQ, Quantinuum, and Rigetti — making it a leading multi-vendor cloud ecosystem. Microsoft is also developing its own topological qubit based on Majorana particles. Its Majorana 1 chip, unveiled in February 2025, aims at a technology that could in theory scale to a million qubits per chip — though the science remains contested. 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 sits within its AWS Braket segment as part of Amazon Web Services. Braket provides cloud access to multiple quantum hardware types from providers like IonQ, Rigetti and D-Wave, 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. Amazon's hardware-agnostic strategy positions it as the 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. In 2019, Google claimed 'quantum supremacy' with its 53-qubit Sycamore processor, and its subsequent 105-qubit Willow chip achieved "below threshold" quantum error correction — a significant milestone, meaning adding more physical qubits reduces rather than amplifies logical error rates. Google is now targeting a million-physical-qubit system with high-fidelity error-corrected logical qubits by the early 2030s, maintaining both experimental hardware labs and in-house chip fabrication facilities.

IBM

IBM is one of the earliest leaders in quantum computing, with the Quantum division offering cloud-based quantum access through the IBM Quantum Experience, supporting over 20 quantum systems globally. IBM uses superconducting qubits and has consistently published a detailed hardware roadmap. Its Heron R2 156-qubit processor now powers cloud systems in the US and EU and supports up to 5,000 two-qubit gates, with IBM targeting a "quantum advantage" demonstration in 2026. IBM's Qiskit platform, an open-source quantum SDK, has arguably become an industry standard.

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. Quantinuum's H-Series quantum processors are modular and upgradeable. The company's software stack includes TKET, a hardware-agnostic compiler. Quantinuum is one of very few quantum companies offering commercial quantum encryption tools and is a named partner across multiple large-cap platforms.

Intel

Intel is pursuing a novel strategy — its qubits are spin qubits in silicon, smaller, faster and more compatible with existing chip fabrication than superconducting or ion-trap qubits. Its 'Horse Ridge' cryogenic control chip operates at extremely low temperatures, reducing the complexity of quantum wiring and enabling better scalability. Intel's plan is to produce millions of qubits using the same lithographic processes as classical chips, potentially enabling large-scale quantum computing at a relatively low cost — including integration with classical processors.

Growth quantum computing stocks to watch

In addition to the tech titans, here are several smaller pure-play quantum companies to consider. These are genuinely high-risk, high-volatility investments — all experienced June 2026 drawdowns of 20-25% with no company-specific negative news, reflecting the sentiment-driven nature of the sector. Position sizing should be kept small within any diversified portfolio.

IonQ (NYSE: IONQ)

IonQ is the market leader in trapped-ion quantum computing by revenue, with approximately $130 million in 2025 sales and 2026 guidance of $225-245 million — a 172% revenue increase over two years. Q1 2026 was described by management as "the biggest quarter in our company's history," with remaining performance obligations of $470 million, up 554% year on year, and the first sale of a 256-qubit Tempo system to the University of Cambridge. IonQ also agreed to acquire SkyWater Technology, expected to close in Q2 or Q3 2026, adding semiconductor fabrication capabilities. However, the adjusted EBITDA loss is guided at negative $310-330 million for 2026, the stock trades at a price-to-sales ratio of approximately 109x, and the stock fell 26% in June despite no negative news — illustrating the extreme volatility and speculative valuation characteristic of the sector.

D-Wave Quantum (NYSE: QBTS)

D-Wave uniquely focuses on quantum annealing — a specialised approach to optimisation problems — rather than the more general gate-based quantum computation pursued by most rivals. Its Advantage2 system is commercially available via both cloud and on-premises models. D-Wave recently acquired Quantum Circuits to accelerate its gate-model roadmap, targeting 17 qubits in 2026, 100 logical qubits by 2032, and its Advantage3 annealer aimed at 100,000 qubits. Unlike other firms chasing fault-tolerant systems years away from commercialisation, D-Wave's annealing architecture enables real-world applications today in logistics, protein folding and supply chain management. The stock trades at a price-to-sales ratio of approximately 791x and fell 21% in June.

Rigetti Computing (Nasdaq: RGTI)

Rigetti is a full-stack quantum computing company that designs and fabricates its own superconducting qubit chips. Its 108-qubit Cepheus-1-108Q system reached general availability across Rigetti QCS, Amazon Braket, Microsoft Azure Quantum and qBraid in 2026, with CEO Subodh Kulkarni describing it as "one of the most powerful generally available gate-based quantum computers in the world." Q1 FY26 revenue of $4.40 million nearly tripled year on year, and the company holds $569 million in cash with no debt — a significant safety cushion bolstered by a letter of intent for up to $100 million in federal incentives from the $2 billion CHIPS Act quantum funding. The stock fell 24% in June and trades at a price-to-sales ratio of approximately 836x.

Quantum Computing (Nasdaq: QUBT)

Quantum Computing focuses on photonic quantum computing and hybrid quantum-classical software solutions. Unlike superconducting or ion-trap systems, its 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 from its Arizona-based quantum photonics foundry and from software licensing. The company remains in the early stages with a relatively small market capitalisation and fell 6% in the same June session that hit the rest of the group.

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 — including $2 billion in US government funding announced in May 2026 — suggests that commercial breakthroughs may emerge in the coming decade. Major tech giants are pursuing quantum strategies via hybrid systems or cloud platforms, while smaller pure-play players are building specific quantum technologies. The June 2026 drawdowns of 20-25% across the pure-play sector, with no company-specific negative news, underscore how sentiment-driven and speculative these stocks remain at current valuations. Investing in quantum computing stocks involves balancing significant potential rewards with high technical risk, long timelines and extreme valuation multiples.

Past performance is not a reliable indicator of future results. The value of investments can fall as well as rise and you may get back less than you invest.