Better Quantum Computing Stock: IonQ vs. D-Wave

Quantum computing has gained increasing attention in recent years. Amid the technology's potential for exponentially faster computing, companies like Alphabet, IBM, and Nvidia have taken an interest in it.

Additionally, many smaller, pure-play quantum computing stocks have emerged, and two of the more prominent ones are IonQ (NYSE: IONQ) and D-Wave Quantum (NASDAQ: QBTS).

Although these stocks carry significant risks, their smaller sizes also offer greater potential for higher returns should they succeed. Thus, it is worth asking which of these stocks might be the better stock to buy.

Image source: The Motley Fool.

The case for IonQ

One limitation of quantum computing is that the technology is often error-prone. This means any company that can minimize that problem has a better chance of success, and IonQ may have the solution with its trapped-ion quantum system.

Last year, IonQ demonstrated 2-qubit gate fidelities of 99.99%. This technology unlocked more complex applications that could now be performed with minimal error rates. While that does not make it faster than its big-tech counterparts, it performs tasks with industry-leading precision.

Furthermore, the company, often called the "Nvidia of quantum," has formed a partnership with that company. Under the terms of the agreement, Nvidia will install the IonQ Superion 256 system at the Nvidia Accelerated Quantum Research Center. This will tie IonQ into Nvidia's ecosystem, which could give it a competitive advantage.

Unfortunately, such gains may not yet provide sufficient support for its financials. Its $145 million in revenue in the first half of 2026 was well above the $28 million in the same period a year ago, indicating it is growing faster than Nvidia. However, high operating expenses led to a $1.06 billion operating loss in the first two quarters of 2026, well above the $210 million loss from the same time frame last year.

Moreover, IonQ stock is down by more than one-third over the last year. Despite that decline, it still has a price-to-sales (P/S) ratio of around 65, an indication that the company's fundamentals have little bearing on the stock price. Such a valuation makes it extremely difficult to forecast IonQ's near-term direction at this time.

Why investors might consider D-Wave Quantum

Nonetheless, investors might also find challenges amid the potential in D-Wave Quantum. In an industry where some have predicted commercial viability is years away, Leap's quantum cloud service already runs customer applications.

Additionally, it has become a leader in optimization, as its quantum annealing technology helps find solutions while analyzing millions of variables. For example, AT&T cut a one-hour task down to less than 15 seconds using this application.

Thus, it is likely not surprising that companies use its technology to retrain AI models, generate molecular structures, and lower energy consumption.

However, much like with IonQ, D-Wave Quantum is far from profitability. In the first half of 2026, revenue of $5.9 million fell 67% year over year, though a large system sale in early 2025 skewed these results. Also, high operating expenses led to a $66 million loss for the same period.

Amid that financial performance, the stock dropped by almost 40% over the last year. Furthermore, at a P/S ratio of approximately 475, the stock's valuation factors in several years of anticipated revenue gains, making the stock a risky buy at this time.

Should investors buy IonQ or D-Wave Quantum?

As conditions stand now, both stocks face deep uncertainty in the foreseeable future, and risk-averse investors should probably avoid both of them. Nonetheless, if choosing one, I recommend IonQ.

Although D-Wave's success at applying the technology now is noteworthy, one cannot deny IonQ's built-in credibility that comes with its Nvidia partnership.

Moreover, while both are too expensive, it is less risky to pay around 65 times sales than it is to buy at a P/S ratio of around 475. Thus, amid significant uncertainty, IonQ looks like the safer buy that offers a higher probability of success.

Will Healy has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Alphabet, International Business Machines, IonQ, and Nvidia. The Motley Fool has a disclosure policy.