Prediction: Amazon Will Surpass Microsoft's Market Cap and Join the $3 Trillion Club By the End of Summer

The market cap gap between Amazon (NASDAQ: AMZN) and Microsoft (NASDAQ: MSFT) is narrowing. Amazon's 6% climb this year may not seem like much. It's not close to beating the market. However, Microsoft's 22% year-to-date drop is bringing the two titans surprisingly close.

Amazon's market cap enters this week at $2.6 trillion. Microsoft has fallen to $2.8 trillion. Simple math suggests that Microsoft will return to the $3 trillion market-cap club first, joining three other "Magnificent Seven" stocks already there. But I don't think it will play out that way. Amazon has the stronger case for passing up Microsoft on the open road, hitting the round $3 trillion mark first. And I think it can happen later this summer.

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You can't spell awesome without AWS

Amazon stock is on a roll, despite what the 2026 stock chart may suggest. The 17% increase in net sales the leading retailer reported in its latest quarter is its strongest top-line growth in four years. Microsoft, on the other hand, is also in a good groove. The 18% year-over-year revenue growth that it has posted in three of its past four quarters is also a four-year high.

Doesn't this make Microsoft the stronger investing opportunity? Its business is also accelerating, and the stock is considerably cheaper than it was six months ago. Things change pretty quickly on Wall Street. Microsoft, with its early investment in ChatGPT parent OpenAI, entered this year as a leader. The narrative has changed.

You can't spell fair without AI

OpenAI is no longer the runaway leader. Anthropic is rivaling OpenAI's valuation, with both companies preparing to go public later this year as the next potential trillion-dollar debutantes. Gemini is also gaining momentum. Meanwhile, instead of seeing Microsoft and its cloud-hosting service, Azure, leading the ChatGPT AI boom, it is suddenly vulnerable.

With other roads to success outside OpenAI, investors are now concerned about what becomes of the Windows operating system and Office 365 productivity suite as platforms in the future. Is the predator becoming the prey? In the meantime, both Amazon and Microsoft are making big nine-figure capital-expenditure investments to remain relevant.

Over at Amazon, Amazon Web Services (AWS) remains the top dog in cloud hosting stocks, contributing more than half of the company's overall operating profit. Its e-commerce stronghold isn't as vulnerable to the AI revolution as Microsoft's key software platforms.

Microsoft may have a leg up on Amazon in terms of valuation. It's trading just shy of 20 times next fiscal year's earnings. Amazon is approaching a multiple of 25. Microsoft's trailing net margin is three times higher. However, Amazon has momentum on its side. Investors may say they want a cheap stock, but what they really want in a new investment is a higher return from a company that has a better chance of being in a better position a year or more from now. Right now, that's Amazon. Don't be surprised when it passes Microsoft and retakes a $3 trillion market cap this summer.

Rick Munarriz has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Amazon and Microsoft. The Motley Fool has a disclosure policy.