Billionaire Steve Mandel and his hedge fund Lone Pine Capital have been a great one to follow for individual investors. Although some hedge funds have a poor record of underperforming the broader market, Mandel has substantially outperformed the market over the past three years. So, when he makes a move in his portfolio, investors should pay attention.

One thing Mandel did during Q2 was sell off some of his Microsoft shares. Although it wasn’t a massive move, the hedge fund reduced its position by about 5%. Then, Mandel used some of those funds to invest in another promising AI stock that has increased in value by nearly 800% over the past decade.

That stock? Amazon (AMZN -1.16%).

AWS is the best reason to invest in Amazon right now

Amazon may not be the first company that comes to mind when you think about AI. Instead, it probably seems more like an e-commerce investment. While that sentiment is true for the consumer-facing portion, the reality is that a large chunk of Amazon’s profits comes from AI-related revenue streams.

The biggest is from Amazon Web Services (AWS), its cloud computing arm. Cloud computing firms are having a strong year, thanks to the massive demand generated by AI workloads. Because more companies can’t justify spending millions (or even billions) of dollars on a data center dedicated to training AI models, it’s far more reasonable to rent computing power from a firm that already has the capacity. That’s the idea behind cloud computing, and it has translated into strong growth for the business unit.

In Q2, AWS’s sales rose 17% to $30.9 billion. That’s strong growth, but it is a bit slower than its peers, Microsoft Azure and Google Cloud, which each grew revenue by more than 30% in Q2. However, AWS is much larger than both of these units, so it shouldn’t surprise investors that AWS is growing at a slower rate. AWS accounted for about 18% of Amazon’s total revenue in Q2, but it made up 53% of its operating profit. That’s because AWS has far superior margins compared to its commerce business units, making AWS a critical part of the Amazon investment thesis.

AWS is experiencing a significant boost from AI, making it a strong stock pick in this space.

But Microsoft is also a solid AI pick, so why is Mandel moving from Microsoft to Amazon?

Amazon’s stock looks more promising over the long term

From a valuation perspective, both companies trade at fairly expensive levels for their growth. However, they’re both priced about the same from a forward price-to-earnings (P/E) standpoint.

AMZN PE Ratio (Forward) data by YCharts

One thing Amazon has going for it that Microsoft doesn’t is the steady upward pressure on Amazon’s margins. Thanks to AWS and its advertising service business units being the fastest growing in Amazon, its margins are steadily improving. Although Amazon’s revenue growth rate appears to be somewhat slow, its operating income growth rate is actually quite rapid.

AMZN Revenue (Quarterly YoY Growth) data by YCharts

This trend still has years to unfold, which is a solid reason to transition from Microsoft to Amazon. I believe this will be a winning trade over the long term, as Amazon’s profits are expected to grow at a significantly faster rate than Microsoft’s, resulting in the stock outperforming its peer over the long term due to their similar valuations.

However, both stocks are still solid AI picks, and you can’t go wrong with either one.

Keithen Drury has positions in Amazon. The Motley Fool has positions in and recommends Amazon and Microsoft. The Motley Fool recommends the following options: long January 2026 $395 calls on Microsoft and short January 2026 $405 calls on Microsoft. The Motley Fool has a disclosure policy.

Apple is the world’s third-largest company by a wide margin, with a $1 trillion gap between it and fourth-place Alphabet . However, I think several companies are slated to pass Apple in market share over the next five years, including fifth-place Amazon (AMZN -0.00%), which is valued at around $2.4 trillion compared to Apple’s $3.5 trillion.

That’s a wide gap to make up in five years, but looking at Amazon’s growth tailwinds versus Apple’s makes it fairly clear that Amazon is the much better stock pick.

Amazon has two business units driving profit growth

Apple’s business is fairly straightforward; it’s the leading consumer tech brand and generates significant revenue selling iPhones and other products in the Apple ecosystem. Amazon is a bit more complex, as it has the online store that most investors are familiar with, but that’s not the best reason to invest in it.

Although its online stores division posted the best quarter in a long time (revenue rose 11% year over year), the real stars of the show are Amazon Web Services (AWS) and its advertising services division.

AWS is Amazon’s cloud computing platform, and it is seeing strong demand fueled by the migration of traditional workloads to the cloud, as well as by new artificial intelligence (AI) workloads. AWS grew revenue by 17% year over year in Q2, which is strong growth considering it generated nearly $31 billion in revenue during the quarter. However, AWS’s primary competitors (Microsoft‘s Azure and Google Cloud) posted stronger growth rates in their corresponding quarters, so investors are worried about AWS’s long-term ability to perform in this sector despite its being the market-share leader.

AWS will likely continue to underperform its peers due to its size, but 17% growth is nothing to sneer at. AWS is also a large part of Amazon’s profit picture. In Q2, it accounted for 53% of Amazon’s operating profits despite accounting for only 18% of revenue. Analysts still expect cloud computing to grow rapidly over the next few years, and if Amazon surpasses Apple in market cap, this will be a primary reason why.

Advertising services is Amazon’s fastest-growing segment, with revenue rising 23% year over year, an acceleration over previous quarters’ growth rate. Amazon has one of the most lucrative places to advertise on the internet, as consumers are already coming to their platform to make purchases. Paying to place a product at the top of an Amazon search almost guarantees increased sales. This is worth a lot to its advertising clients and will be a key part of Amazon’s investment thesis over the next few years.

Amazon’s margins are rising

Amazon isn’t a revenue growth story; it’s a profit growth story. The rise of high-margin businesses like AWS and advertising services has helped Amazon boost its profit margins over the past few years.

AMZN Profit Margin data by YCharts

With its two high-margin business segments growing faster than other parts of its business, Amazon will naturally have elevated profit growth rates. In Q2, Amazon’s operating income rose 31% year over year.

Contrast that with Apple, whose Q3 FY 2025 (ending June 28) operating income increased by 11%. Amazon’s profit growth rate is much faster. Over five years, a 30% growth rate will increase its operating income by 271% while an 11% growth rate increases operating income by only 69%.

That would be enough to drive Amazon’s profits higher than Apple’s, propelling it to surpass it in size along the way. Amazon is an excellent stock pick for the next five years and a no-brainer buy at today’s prices.

Keithen Drury has positions in Alphabet and Amazon. The Motley Fool has positions in and recommends Alphabet, Amazon, Apple, and Microsoft. The Motley Fool recommends the following options: long January 2026 $395 calls on Microsoft and short January 2026 $405 calls on Microsoft. The Motley Fool has a disclosure policy.