Better Quantum Computing Stock for 2026: IonQ or Rigetti Computing?

The quantum computing investment landscape has shifted multiple times in 2025. At the start of the year, after an impressive December 2024, quantum computing pure-play stocks all sold off. Throughout 2025, upward momentum returned, and several quantum computing stocks are on course for impressive one-year returns. However, these stocks all sold off starting in October as the market's appetite for risk declined.

IonQ (NYSE: IONQ) and Rigetti Computing (NASDAQ: RGTI) are both well down from the highs they touched in October: IonQ is off by around 43%, while Rigetti is down about 60% from its peak. Could either one enjoy a resurgence in 2026?

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Two different approaches to quantum computing

All quantum computers are built around "qubits" -- quantum bits -- which they use to process computations. But those qubits can be created in a number of ways. The most common is to cool a specially constructed circuit down to nearly absolute zero, which makes it a superconductor and causes its behavior to be governed by quantum mechanical principles.

Rigetti Computing uses these superconducting qubits, as do many other big names in the industry, such as Alphabet (NASDAQ: GOOG)(NASDAQ: GOOGL) and Microsoft (NASDAQ: MSFT).

IonQ uses a technology that fewer companies are pursuing: trapped ion qubits. Each of its qubits is a single charged atom, held in an electromagnetic field, and cooled to near absolute zero using lasers.

It's the industry leader among the companies taking this approach, which has some advantages over the more popular superconducting approach. It has high fidelity and accuracy, and its qubits can hold their quantum states for a relatively long time, which is highly beneficial when running multistep algorithms. Error reduction and error correction are among the key concerns in the quantum computing realm right now. By using an approach that maximizes accuracy, IonQ has become a leader among the pure-play companies in the space.

IonQ has achieved 99.99% two-qubit gate fidelity, a measurement of how accurate a calculation is after passing through two operators. None of the companies using superconducting qubits has managed to breach the 99.9% threshold, so IonQ's lead is significant.

However, the trapped ion approach also has its drawbacks.

Compared to superconducting qubits, trapped ion qubit machines have slower processing speeds. When accuracy is the chief concern, speed is less of a consideration. However, there could come a day when all competitors have achieved acceptable accuracy levels, and speed will become the focus. If all companies reach that threshold around the same time, then IonQ could be destined for failure. Its best hope is to beat the competition to the punch and establish an early foothold in the quantum computing market. If it can do that, then IonQ could be a successful stock pick.

Rigetti Computing is trying to close the gap with IonQ, but so far, it has been striking out. There isn't a huge market for quantum computers right now, and the market that does exist is mostly limited to research contracts. Winning some of those few contracts is extremely important for the pure plays' long-term viability.

One of the most important things going on in the sector is the Quantum Benchmarking Initiative being run by the Defense Advanced Research Projects Agency (DARPA). In simple terms, the federal government is trying to determine which quantum computing technologies (if any) could fulfill their promise cost-effectively and at commercial scale -- and specifically what such a system could do that a standard supercomputer can't. Unfortunately for Rigetti, it wasn't selected for Stage B of the initiative, while IonQ was (along with 10 others).

While DARPA has been clear that the companies involved are not all working on the same timelines, and that more are likely to be added to the Stage B group later, Rigetti's current status is a problem that causes me to lean more toward IonQ as the stock to go with in 2026. However, in both cases, their share price performance may be largely out of their control.

The market's risk appetite will be key for these stocks

In reality, useful quantum computing is still years away, with many pointing toward 2030 as the start of commercially viable quantum computing. DARPA's initiative is looking for companies that can reach "utility-scale operation" by 2033. Either way, that's a long time for investors to wait for real business to start. As a result, quantum computing stocks are highly volatile. High-risk, high-potential-reward investing isn't for everyone. If you're not comfortable with it, an exchange-traded fund (ETF) approach to investing in this space may be a better option for you.

The success of quantum computing stocks in 2026 will be tied to the market's appetite for risk more than the actual successes of those companies -- particularly since their valuations today are highly speculative. If the market is feeling risk-averse (like it is in December), these stocks may struggle. If investors' appetite for risk rises (as it did in the middle of 2025), both stocks could be great to own.

However, I prefer to own companies that control their own destiny. With both IonQ and Rigetti going up against some stiff and well-funded competition (like Microsoft and Alphabet), and reliant on the market's mood for their share price performance, the chances of either company being a successful investment next year are low. But if they work out over the long term, they could be monster winners.

Keithen Drury has positions in Alphabet. The Motley Fool has positions in and recommends Alphabet, IonQ, and Microsoft. The Motley Fool recommends the following options: long January 2026 $395 calls on Microsoft and short January 2026 $405 calls on Microsoft. The Motley Fool has a disclosure policy.