Fans of quantum computing stocks are no doubt familiar with quantum computing unit (QCU) maker Rigetti Computing (RGTI 4.46%). The quantum chipmaker has won several fans and seen its share price soar over the past year. But Rigetti's stock is now trading more than 60% off its 2025 high, and it's even given back all of the gains it's made so far in 2026.
So is now a good time to buy this up-and-coming quantum computing stock?
Speed, accuracy, and scale
The quantum computing industry is still in its infancy. But that hasn't stopped companies from jumping into it. Start-ups like Rigetti are competing with tech giants like Alphabet's Google and IBM to develop the tech that could become a commercially viable product.
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Essentially, all these companies are trying to optimize their quantum computers on three separate metrics: speed, accuracy, and scale. Speed refers to the amount of time it takes a quantum system to manipulate a quantum particle at a "quantum gate," and then to move it to the next gate and prepare it for its next computation.
Accuracy is commonly measured by "two-qubit gate fidelity," and refers to the percentage of computations that are error-free within the system. Scale is the number of physical qubits in a quantum system. The difficulty for all quantum companies is that as scale and speed increase, accuracy tends to decrease.
It seems likely that the companies able to maximize their systems' performance through a combination of speed, accuracy, and scale are most likely to be among quantum computing's big winners. How does Rigetti compare to its rivals in this regard?
NASDAQ: RGTI
Key Data Points
How Rigetti stacks up
The speed of Rigetti's systems is quite impressive. It claims that its 108-qubit system -- roughly the largest-scale system available today -- has achieved gate speeds of 50-70 nanoseconds. That's incredibly fast.
But the median accuracy of that 108-qubit system is only 99% as measured by two-qubit gate fidelity. That may sound like a great rate, but in the world of quantum computing, differences of even 0.01% are significant.
The company's smaller systems are more accurate, though. Its 36-qubit system has achieved two-qubit gate fidelity of 99.6%, and its 9-qubit system has reached 99.7%. The problem here is that rival IonQ (IONQ 1.72%) boasts that it has achieved 99.99% fidelity in a 100-qubit system. To be fair, though, IonQ's systems, although much more accurate than Rigetti's, are much slower.
Rigetti CEO Dr. Subodh Kulkarni said last month in a press release that the company has "a clear understanding of what we need to do to achieve 99.5% median two-qubit gate fidelity" in its Cepheus-1-108Q system, which is set to be released this quarter. But even if it can achieve that benchmark, there's still a long way to go.
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Where Rigetti needs to be
For a quantum computer to be commercially viable, it's estimated to need at least 1 million physical qubits and 99.99% two-qubit gate fidelity (and probably closer to 99.99999%). So we're still a long way from quantum computing becoming mainstream.
Rigetti believes it's on track to develop a system with 1,000 qubits by 2027 with 99.7% two-qubit gate fidelity, but hasn't given longer-term estimates. Rival IonQ is targeting a 10,000-qubit system by 2027 and a 2 million-qubit system by 2030. If Rigetti scaled up on a similar trajectory, it would achieve a 200,000-qubit system by 2030 and surpass the 1 million-qubit threshold by 2031.
But there's no way to know how accurate such a massive system would be, nor whether Rigetti can beat IonQ to the punch as well as deep-pocketed rivals like Google and IBM.
The bottom line for investors
So, is Rigetti a buy now? Nobody but the most risk-tolerant investors should even consider it: The company is too speculative, and a lot can change between now and 2030.
Image source: Getty Images.
On the bright side, according to data from McKinsey & Company, the quantum computing market could be as large as $72 billion by 2030. If Rigetti can control a large enough piece of that pie, it could be a huge winner from here. But a lot would have to go Rigetti's way for that to happen, and right now there's no way to know how things will shake out in this rapidly developing field.
For investors who want to buy into the quantum computing trend early, Rigetti isn't a bad choice, but it's probably not a good idea to put all your eggs in one (quantum) basket. I would rather take a small stake in Rigetti alongside other quantum computing companies, or invest in a quantum computing ETF so I could give myself the best odds of picking a winner. And I definitely wouldn't invest money I couldn't afford to lose.
