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If we go by IBM’s quantum computing roadmap, the first fault-tolerant quantum computer should arrive in 2029. If it materializes, this milestone should mark the beginning of the sector’s growth. So far, quantum computing systems are yet to win the war against decoherence.

Namely, physical qubits are inherently too fragile to transform into robust logical qubits,making quantum error correction (QEC) as important as developing the system itself.

QEC, a set of procedures and algorithms, not only detects and mitigates errors but is also the fundamental mechanism for transforming unreliable physical qubits into high-fidelity logical qubits to finally reach quantum advantage over classical computing.

With this in mind, which companies have demonstrated steady quantum computing progress?

Honeywell International Inc. (HON)
 

Although not typically perceived as a quantum computing company, Honeywell has two major advantages. First, as long as the dollar maintains its global reserve currency status, Honeywell will continue to serve the military industrial complex with its aerospace systems, alongside land, naval, satellite and autonomous systems.

Honeywell’s Aerospace Technologies (AT) division represented around 42% of the company’s total revenue in Q3 2025, with $4.5 billion (up 15% YoY) out of $10.4 billion total revenue across Industrial Automation (IA), Building Automation (BA) and Energy and Sustainability Solutions (ESS).

Secondly, Honeywell has a majority stake in Quantinuum, which has a pre-money valuation of $10 billion, after a $600 million fundraising round in September. In early November, Quantinuum introduced Helios as “the most accurate quantum computer in the world”.

According to a paper published on arXiv (operated by Cornell University), Helios achieved single-qubit gate fidelity of 99.9975% by connecting 98 physical qubits with its ion-trapping approach. Effectively, Quantinuum has 94 logical qubits to work with.

For context, to break Bitcoin’s private key encryption algorithm, it is estimated one would need a computer with over 2,300 logical qubits. To scale Helios fidelity further, Quantinuum will leverage Nvidia’s Grace Hopper GPUs in order to run decoding (from QEC) in real-time.

Suffice to say, Honeywell is the safest quantum exposure through its important but relatively minor Quantinuum bet. Year-to-date, HON stock is down 5.5%. Against its current price of $199.32, the Wall Street Journal’s consensus is $235.95 per share. More importantly, the current price range is very close to its bottom target of $195, suggesting optimal exposure entry.

D-Wave Quantum (QBTS)
 

Exposure to D-Wave Quantum is an exposure to an alternative quantum approach. While other companies are attempting to achieve universal quantum computers, D-Wave employs quantum annealers to offer superior optimization solutions.

Just as a ball would eventually find the deepest bottom by rolling down a complex landscape, quantum annealing uses effects such as quantum superposition and tunneling to find the global minimum energy state of a problem.

In the context of solving combinatorial optimization problems (logistics, supply chains, portfolio optimization), the minimum energy state corresponds to the optimal solution. Tunneling comes in as a way to pass through energy barriers rather than having to climb over them, thus enabling more efficient solution-finding.

A study in February suggests that this approach relies less on quantum coherence aspects and more on the thermal (dissipative) and stochastic (Markovian) aspects.

“Furthermore, we have shown that by ignoring in the simulations, the coherent parts, a non-quantum Markovian master equation could also reproduce the salient features of the D-Wave data. This suggests that the coherent part of the dynamics does not play a crucial role in the reverse annealing regime in D-Wave.”

As such, D-Wave’s approach is complementary to classical computing. In other words, D-Wave’s annealers offload hard subproblems to quantum processors while classical computers manage preprocessing, decomposition and reconstruction.

Case in point, the company’s Advantage2 system (4400 qubits) found its way into the European supercomputer hub, the Jülich Supercomputing Centre (JSC). In early November, Davidson Technologies, an engineering firm entangled in DoD also adopted Advantage2 for mission-critical challenges.

The company’s push toward a hybrid approach rests on the belief that trapped-ion and neutral-atom systems lack a viable path to scaling without fundamental breakthroughs and massive capital investment. Funding trends appear to support this view: D-Wave’s cash position rose to $836.2 million in Q3 2025 from merely $29.3 million in the year-ago quarter.

The current price of QBTS shares, at $24.38, is significantly below their bottom price target of $35, while the average price target of QBTS stock is $39.64 per share.

IonQ Inc. (IONQ)

As the company’s name indicates, IonQ’s main focus is trapped-ion qubits due to having higher coherence times and lower error states, just like Honeywell’s Quantinuum. For contrast, both IBM and Google use superconducting qubits, seen as a more viable path in terms of scaling.

However, IonQ has gone the farthest in developing a commercial portfolio, from 2021’s Aria (25 algorithmic qubits) to Tempo in 2025, with its 64 AQ, 100 target qubits and 99.9% fidelity. Long-term, the company is planning to increase qubit range beyond 10k. For 2026, IonQ is aiming for a 256-qubit system demonstration.

Some of these systems found themselves in Hyundai, AstraZeneca, Oak Ridge National Laboratory, Ansys and Airbus. DARPA also picked IonQ for its Quantum Benchmarking Initiative (QBI), currently in stage B ahead of the last stage C. At that final stage, selected companies will have their actual hardware independently tested and validated for real-world use.

With $3.5 billion in net cash in Q3, IonQ appears to be the most funded among quantum-only focused companies. If all goes well with the aforementioned 256-qubit system, this will be a major milestone for investors.

Accordingly, most analysts are bullish on IONQ stock. Against its current price of $47.12, the bottom target is close at $47, while the average price target for IONQ stock is $75.50 per share.

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