Yesterday was World Quantum Day, a day dedicated to raising awareness of the physics that powers the quantum computers of tomorrow.
But awareness of quantum technology wasn’t the only thing that was rising. So, too, were the stock prices of America’s four major quantum computing companies: D-Wave, IonQ, Rigetti, and Quantum Computing Inc.
And today, the stock prices of those four companies are even higher. Here’s why.
Quantum computing stocks soar
If you’re an investor in any of the so-called Quantum Four quantum computing companies, yesterday was a good day. All four major American quantum computing companies saw double-digit gains yesterday, including:
- D-Wave Quantum Inc. (NYSE: QBTS): up 15.8% to $16.97
- IonQ, Inc. (NYSE: IONQ): up 20.1% to $35.76
- Quantum Computing Inc. (Nasdaq: QUBT): up 11.5% to $8.11
- Rigetti Computing, Inc. (Nasdaq: RGTI): up 11.5% to $16.87
Those are significant one-day gains. But they haven’t stopped there. As of the time of this writing, in premarket trading today, all four quantum stocks are on the rise yet again.
Currently, D-Wave is up another 8%, IonQ is up another 4.6%, Quantum Computing Inc. is up another 3.7%, and Rigetti is up another 5%.
But the question is: Why?
IonQ and D-Wave lift quantum computing stocks
While it may be tempting to believe that interest in World Quantum Day had something to do with the surge in quantum computing stock prices, that likely wasn’t the main driver (though some retail investors may have gotten curious about quantum computing due to World Quantum Day and decided to buy in).
Out of the Quantum Four, the two biggest gainers yesterday were IonQ, up over 20%, and D-Wave, up almost 16%.
And both of these companies made significant announcements, spurring their stock prices higher.
What did IonQ announce?
Yesterday, IonQ announced it had made a “foundational technical milestone” for the industry. The company says that it photonically interconnected “two independent trapped-ion quantum systems”—in other words, it linked two remote quantum computers together.
Right now, quantum computers, while powerful, operate independently. But if quantum technology is to usurp classical computers, quantum ones will ultimately need to be networkable, allowing them to interface with one another and share data across an interconnected grid.
Additionally, IonQ also announced that it secured a contract with the Defense Advanced Research Projects Agency (DARPA) based on its networking advancements, so it’s no wonder that it got investors excited.
What did D-Wave announce?
As for D-Wave, the company’s CEO spent World Quantum Day espousing the benefits of quantum computing, especially how it compares to the current AI wave taking over the tech industry, which Nvidia has mainly benefited from.
As reported by Yahoo Finance, while speaking at the Semafor World Economy Summit in Washington, D.C., this week, D-Wave CEO Alan Baratz said, “If I was Nvidia, I’d be shaking in my boots,” regarding the capabilities of quantum computing.
The reason Baratz says Nvidia should be shaking is that its GPUs, which power AI processes, require a lot of power to run on compared to quantum computers. And Nvidia’s GPUs are only capable of running classical computations, not quantum ones.
Baratz pointed out that D-Wave’s “quantum computer takes about ten kilowatts of power to run,” which is about the same amount that five or ten AI GPUs currently require.
But a quantum computer can also process tasks in minutes that it would take classical computers millions of years to do.
In other words, if quantum computers will be able to carry out tasks in minutes using a minute fraction of the time it takes classical GPUs to do so, that will enable companies to drastically cut their energy consumption bills—which will serve as a massive incentive to switch from running their compute tasks on classical GPUs to quantum computers.
The news around IonQ and D-Wave seems to have had a predictable effect on Quantum Four stocks.
Often, good news from one company will cause investors to buy into all four, seeing the news as a signal that quantum technology is advancing, and so any company operating in the space is worth looking at again.
Quantum computing stocks have had a rough 2026
Despite all four quantum stocks seeing massive gains yesterday, the Quantum Four have had a rough 2026.
As of yesterday’s close, all four companies were still in the red for the year, with D-Wave down 35% year-to-date, IonQ down 20%, Rigetti down 23%, and Quantum Computing Inc. down almost 21%.
As Fast Company previously reported, while 2025 was a great year for the stock prices of the Quantum Four, 2026 saw investors sour on the four companies.
Part of this was due to fears that while quantum computing is a promising technology, real-world widespread use is still likely a decade or more away—which means significant profits are still years off.
But the Quantum Four also saw their stock prices plummet due to factors outside their control—as did the stock prices of most other tech companies.
These factors included fears that an AI bubble could drag the tech sector down, that inflationary pressures could further hurt consumer confidence, and that geopolitical events such as the war in Ukraine and the ongoing conflict in Gaza could further send the world into turmoil (and this was before America’s war on Iran even happened).
So while investors may be cheering quantum stocks again today, recent history shows that investor sentiment can quickly sour, and not even a quantum computer could confidently predict how quantum stocks will be performing when World Quantum Day rolls around next year.