There have been several successful investments in the AI realm that have made investors millionaires over the long run. Take the king of AI computing, Nvidia. A $10,000 investment in Nvidia a decade ago is now worth around $3 million, easily accomplishing the goal of turning a modest investment into $1 million.
While there is still huge growth in the AI realm, many investors are turning toward quantum computing as the next big industry. I've got a list of three stocks that could make investors a millionaire, although there's no guarantee, as quantum computing is a highly competitive realm with unknown feasibility.

Image source: Getty Images.
The contenders have differing approaches to quantum computing
Three stocks that I think are solid candidates to make investors $1 million are IonQ (IONQ 5.14%), Rigetti Computing (RGTI 13.12%), and D-Wave Quantum (QBTS 11.95%). These are some of the top quantum computing pure plays, which are a requirement to make the return levels being discussed here.
While legacy tech companies like Alphabet and IBM are competing in the quantum computing space, they're already too large to transform a modest investment into $1 million. For the legacy tech companies, the upside isn't there. But the floor is much higher. If both companies' quantum computing investments flop, they still have a base business to fall back on. If IonQ, Rigetti Computing, or D-Wave Quantum fail, their stocks will go to zero. This makes the cohort risky, but could provide huge returns as a result.
All three of these quantum computing competitors are taking a different approach to quantum computing. IonQ is using a trapped-ion approach, which can be performed at room temperature and provides leading calculation accuracy. Rigetti Computing is using the more popular superconducting technique, which requires cooling a particle down to near absolute zero. This is the technique that most major players in the quantum computing space are taking, as it provides superior processing speeds.
Lastly, D-Wave quantum isn't trying to build a broad-purpose quantum computer like IonQ or Rigetti is. Instead, it's developing a quantum annealing computer that excels in optimization problems. Considering that AI models and logistics networks are two possible applications for this technology and are expected to drive a lot of the demand in this industry, D-Wave's approach may be a winning one.
It's impossible to know which one of these techniques pans out, or if any of them will. That's why quantum computing investing is so risky, and investors must take proper precautions in this space. With risky picks like IonQ, Rigetti Computing, or D-Wave, investors should devote no more than 1% of portfolio allocations to these stocks. That way, if they do go to $0, they won't affect your overall profit a lot. But that 1% investment can provide huge returns if it can duplicate the decade-long performance of a stock like Nvidia.
Each company must transform into a tech giant to make investors millionaires
If each stock transformed a $10,000 investment into $1 million, it would need to provide 100x returns. That means IonQ would be a $1.8 trillion company a decade from now if it were to provide that level of returns. Rigetti would be a $965 billion business, and D-Wave Quantum would be a $845 billion company.
This would place these three among the largest companies in the world, which seems like a tall task. However, nobody expected Nvidia to become the largest company in the world a decade ago, so this may not be as outlandish as it appears.
It's impossible to know if any of these stocks will be a millionaire-maker or worth anything at all a decade from now. However, there's likely a huge application for quantum computing available. This makes these stocks intriguing and will likely contribute to them rising more in the future. Time will tell if these initial gains will stick or are just hype, but with a meager investment in all three of these stocks, investors can capitalize on the upside while limiting downside risk by spreading their money across three quantum computing investments.