Once-in-a-decade investment opportunities come along... about once in a decade. In the 1980s, the big opportunity was in personal computers. In the 1990s, it was the internet. The 2000s brought the rise of mobile phones and social media. Cloud computing and artificial intelligence (AI) were the biggies of the 2010s.
What's the once-in-a-decade investment opportunity of the current decade? Generative AI is a top candidate. However, quantum computing also deserves recognition. And I think three quantum computing stocks, in particular, could be excellent choices for long-term investors to buy and hold.
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1. Alphabet
Alphabet (GOOG 2.48%) (GOOGL 2.43%) benefited tremendously from the adoption of mobile phones and social media, with Google Search, the Android operating system, and YouTube. Google Cloud has grown significantly with the shift from on-premises IT to the cloud and the surge in generative AI.
The company is also poised to be a major winner in quantum computing. Its Google Quantum AI unit is already a pioneer in the technology.
In October 2019, Google Quantum AI made headlines when its researchers achieved quantum supremacy. The term refers to using a quantum computer to perform a calculation that would take an impractically long amount of time for the world's fastest classical computers to handle.
NASDAQ: GOOGL
Key Data Points
That was only the first significant milestone in Google Quantum AI's quantum computing efforts. In 2023, the unit demonstrated the first logical qubit prototype, proving that it's possible to reduce quantum computing errors while increasing the number of qubits.
I predict that Google Quantum AI will achieve its goal of building a large, error-corrected quantum computer supporting at least 1 million qubits within the next few years. Meanwhile, Alphabet will also almost certainly remain a leader in AI, cloud, and mobile technologies.
2. Microsoft
Microsoft (MSFT 1.18%) shares several things in common with Alphabet. Both are technology giants. Both rank as top-tier cloud service providers. Both have enjoyed strong tailwinds from generative AI.
Like Alphabet, Microsoft is also a key player in quantum computing. The company has even developed a unique approach to quantum processing that sets it apart from all others.
NASDAQ: MSFT
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In February 2025, Microsoft introduced its new Majorana 1 quantum chip. This chip uses a new type of material called a topological superconductor, or topoconductor. A topoconductor is neither solid, liquid, nor gas. Instead, it represents a topological state. Microsoft believes the technology has the potential to enable squeezing 1 million or more qubits onto a single chip that can fit in the palm of a person's hand.
That's a bold claim. If Microsoft delivers on the promise of its topoconductor technology, the company could well be the biggest winner in the quantum computing industry over the next decade and beyond.
3. IonQ
Not every quantum computing stock to consider buying and holding already has a market cap measured in the trillions. IonQ's (IONQ 0.23%) market cap currently stands at roughly $18 billion.
One reason IonQ deserves investor attention is its trapped-ion architecture. This approach uses single atoms as its building blocks for quantum computing. The company believes its technology reduces quantum errors, enables every qubit to interact with every other qubit directly, and increases qubit coherence. Coherence refers to how long a qubit remains in superposition (i.e., exists in multiple states). The greater the coherence, the longer the quantum computer can perform calculations.
NYSE: IONQ
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Another plus for IonQ is that it's addressing multiple areas of quantum technology. In addition to the company's trapped-ion quantum computers, the company is developing quantum networking, sensing, and security solutions. IonQ refers to itself as "the only quantum platform company in the world." That's not an exaggeration at this point.
To be sure, investing in IonQ is riskier than investing in Alphabet or Microsoft. The company remains unprofitable. As a pure play, its fortunes rest entirely on quantum technology. However, IonQ could conceivably generate greater long-term returns if its research and development pays off.
