The first thing that jumps out in Amazon stock vs MercadoLibre stock is growth speed. MercadoLibre reported Q4 2025 revenue of $8.76 billion, up 45% from a year earlier, and that marked its 28th straight quarter of revenue growth above 30% (Motley Fool, February 2026). Brazil GMV rose 35%, Mexico GMV rose 35%, and advertising revenue climbed 67% as AI-driven bidding tools gained traction (Motley Fool, February 2026).

Amazon is growing at a different pace, from a much larger base. Its Q4 2025 net sales increased 14% to $213.4 billion, or 12% excluding foreign exchange, according to its earnings release (Amazon IR, February 2026). AWS revenue rose 24% to $35.6 billion, its fastest growth rate in 13 quarters, while advertising revenue reached $21.3 billion, up 22% year over year (Amazon IR, February 2026).

That growth gap matters. A company growing 45% annually has more room to surprise investors than one growing in the low teens. The catch, of course, is valuation. If the price already reflects the better growth, the argument gets thinner. In this case, it does not.

MercadoLibre trades at roughly 27 times EV/EBIT even with margins compressed, while Amazon trades at a similar multiple on the same basis (Motley Fool, March 2026). When the multiples are close, the faster grower usually deserves the first dollar.

This is the point where the market’s reaction starts to look too neat.

MercadoLibre’s operating margin fell to 10.1% in Q4 2025, down from 13.5% a year earlier (Wedbush/Finterra, February 2026). That looks ugly until the reason comes into focus. Management said roughly 5 to 6 percentage points of margin pressure came from deliberate spending on free shipping, credit cards, first-party commerce, cross-border trade, and logistics expansion (Motley Fool, February 2026).

That spending is already doing some work. Logistics unit costs in Brazil fell 11% as the network absorbed more volume, and MercadoLibre now handles delivery for about 95% of marketplace items, with roughly half of those volumes stored and fulfilled through company-operated centers (Seeking Alpha, March 2026). Credit card cohorts older than two years are already profitable at a NIMAL level, and the credit card book’s NPL ratio hit an all-time low of 4.4% in Q4 2025 (Motley Fool, February 2026).

The skeptical view is not foolish. Morgan Stanley’s concern, as summarized in a later report, is that MercadoLibre is being treated more like a capital-intensive lender than a pure technology platform (Wedbush/Finterra, February 2026). That matters because the company’s credit book reached $12.5 billion, Brazil’s Selic rate sits at 15%, and higher rates make funding expensive (Wedbush/Finterra, February 2026).

JPMorgan, for its part, upgraded the stock to Overweight and called the selloff a buying opportunity (Wedbush/Finterra, February 2026). That is a judgment, not a fact, and it should be treated as such. The sourced point is simpler: MercadoLibre is compressing margins on purpose, not because the business has stopped working.

Amazon’s margin story runs the other way. Its overall operating income reached $25 billion in Q4 2025, and the company said retail margin gains and AWS strength pushed its overall operating margin to 11.8% over the trailing 12 months, an all-time high (Amazon IR, February 2026; Motley Fool, March 2026). Amazon is already in harvest mode. MercadoLibre is still planting.

The Amazon comparison matters because MercadoLibre is not just an e-commerce story. It is building a platform that looks more and more like its own version of Amazon’s flywheel, only earlier in the cycle and moving faster.

Mercado Pago’s monthly active users have grown nearly 30% for ten consecutive quarters, assets under management are close to $19 billion and up 78% year over year, and the credit portfolio nearly doubled to $12.5 billion, with almost 3 million new credit cards issued in Q4 alone (Motley Fool, February 2026). That is not a side business. It is the financial plumbing that keeps pulling customers deeper into the commerce ecosystem.

The ad business fits into the same loop. MercadoLibre is now the third-largest digital advertiser in Latin America, with about 7% market share in a market management expects to more than double (Seeking Alpha, March 2026). Record Net Promoter Scores in Brazil, Mexico, Argentina, and Chile suggest the user experience is improving at the same time the company is spending heavily (Motley Fool, February 2026).

Amazon’s ecosystem is more mature and, in some ways, more defensible. Its retail business remains powerful, Prime keeps users inside the tent, AWS is still the crown jewel, and advertising keeps scaling. Amazon also said it expects to invest about $200 billion in capital expenditures in 2026, aimed at AI infrastructure, custom chips, robotics, and its low earth orbit satellite network (Amazon IR, February 2026).

That is a strength, but it is also a drag on near-term free cash flow. Amazon reported trailing twelve-month free cash flow of $11.2 billion in its Q4 2025 call (Motley Fool, February 2026). Investors buying Amazon are paying for a company with durable scale and a deep AI engine. Investors buying MercadoLibre are paying for a younger ecosystem that still has more runway.

The best growth stock Amazon or MercadoLibre is not just a question of upside. It is also a question of which risks are visible enough to price correctly.

MercadoLibre’s biggest risk is the credit book. The company’s own transcript said credit card NPLs hit 4.4% in Q4 2025, but a separate analysis said overall NPLs rose to 7.6% in the latest quarter (Motley Fool, February 2026; Wedbush/Finterra, February 2026). The gap probably reflects different portfolio definitions, but it still deserves attention. In Latin America, macro pressure does not need much encouragement to show up in borrower behavior.

There is also currency and regulatory risk. MercadoLibre operates in 18 countries, and Brazil’s possible cross-border taxation rules could either help the company against low-cost Asian competitors like Temu or complicate its own cross-border business (Business Wire, February 2026; Wedbush/Finterra, February 2026). That is the price of doing business across the region. It is also why the stock can move hard in both directions.

Amazon’s risks are different and easier to map. Antitrust scrutiny is a constant. The $200 billion capex plan is large enough to make any allocator blink twice. Competition in cloud from Microsoft and Google remains real, even as AWS accelerated to 24% growth and reached a $142 billion annualized run rate (Amazon IR, February 2026). Still, Amazon’s risks are familiar. MercadoLibre’s are messier because they combine consumer credit, macro exposure, and multiple currencies.

That does not make Amazon safer in a simple sense. It makes it more legible.

If the question is which stock to buy first in a market pullback, MercadoLibre has the stronger case.

It is growing much faster, its valuation is still close to Amazon’s, and its margin pressure is coming from investment rather than obvious decay. Q4 2025 showed 45% revenue growth, 67% advertising growth, nearly 30% fintech user growth, and 78% growth in assets under management, all while customer satisfaction improved in key markets (Motley Fool, February 2026). That is a business spending to extend its lead.

Amazon is the more mature compounder. It generated $80 billion in operating income in 2025, reported 12% full-year net sales growth to $716.9 billion, and is using its scale to push harder into AI, chips, robotics, and logistics (Amazon IR, February 2026). There is nothing weak about that. It is just less explosive.

So the decision rule is straightforward. Choose Amazon if the priority is steadier compounding, visible cash generation, and direct AI exposure. Choose MercadoLibre if the goal is faster growth and higher upside per dollar, with the stomach for Latin American macro risk and a credit book that still needs to prove itself through a full cycle.

If only one gets bought first, MercadoLibre looks like the better buy.