Biggest isn't synonymous with best when it comes to investing. Sure, larger companies are often less risky than smaller ones. But with greater risk, there's usually a higher potential for reward.
Nvidia (NVDA 2.18%) ranks as the biggest stock on the market right now based on market cap. It's probably not the best stock to buy, though. Should you forget Nvidia and instead buy two potential millionaire-maker stocks?
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A rising star in quantum computing
If there's any new technology that offers the promise to make millionaires out of some early investors, it's probably quantum computing. IonQ (IONQ -5.73%) stands out as one of the brightest rising stars in the sizzling-hot space.
Quantum computing and networking could have a total addressable market of $87 billion by 2035. That's just the tip of the iceberg, though. These technologies could create economic value of up to $880 billion by 2040 and be used in a wide variety of applications, such as artificial intelligence (AI), cryptography, logistics, risk management, simulation, and more.
IonQ's trapped-ion architecture offers several competitive advantages, notably including high fidelity, better error correction, and lower system costs. The company's recent acquisition of Oxford Ionics could enable it to pack more qubits on a chip than rivals.
Airbus (EADSY 1.12%), AstraZeneca (AZN -0.57%), General Dynamics (GD 0.88%), and Hyundai are just a few of the big customers that have already signed up to use IonQ's quantum computers. The company's partners include Nvidia, Amazon (AMZN 1.55%), Alphabet's (GOOG -0.67%) (GOOGL -0.46%) Google Cloud unit, and Microsoft (MSFT 0.18%).
IonQ has delivered an impressive revenue compound annual growth rate (CAGR) of 175% since 2021. It also has an ambitious product roadmap through the end of the decade that could keep this momentum going.
An AI hyperscaler that's competing with titans
AI is creating huge opportunities for investors to make a lot of money, too. Running AI models requires massive processing capabilities. Nebius Group (NBIS 3.65%) ranks among the few AI hyperscalers that have the expertise and scale to meet the rapidly growing AI infrastructure demands.
You might be wondering if a relatively small company like Nebius Group, which has a market cap below $30 billion, can really compete against the cloud titans -- Amazon Web Services (AWS), Microsoft Azure, and Google Cloud. I think Nebius' financial performance provides the answer. The company's revenue skyrocketed 625% year over year in the second quarter of 2025 and more than doubled from the previous quarter.
Unsurprisingly, Nebius Group has been one of the stock market's biggest winners this year. Its share price has jumped more than 6x. That makes Nvidia's year-to-date return of almost 50% seem lackluster.
Can Nebius Group keep up its winning ways? CEO CEO Arkady Volozh said in the company's Q2 update, "Demand for AI infrastructure -- compute, software, and services -- is only going to get
stronger as use cases multiply." I think he's right.
One of the biggest challenges for Nebius Group, though, is having the electric power it needs to meet demand. The good news on this front is that the company is working to secure more than 1 gigawatt of power by the end of 2026.
Better picks than Nvidia?
Are IonQ and Nebius Group better picks than Nvidia? Probably the best answer is... maybe.
Both stocks are riskier than Nvidia. Neither IonQ nor Nebius Group is profitable at this point, while Nvidia is rolling in money. These two smaller companies also face significant competition. Nvidia does, too, of course. However, its GPUs continue to dominate the AI chip market.
On the other hand, IonQ and Nebius Group arguably have more room to run than Nvidia. It's a lot easier for a stock to double when its market cap is under $30 billion than it is when the market cap hovers around $4.5 trillion.
I think that IonQ and Nebius Group might be bigger winners than Nvidia over the next 10 years. But my view is that Nvidia is the safer choice.
