Payments Scale & TechnologyNarrow moat

Beneath the distribution and the banking ambitions sits the original business: acquiring — the processing of card payments for merchants — which still moves the enormous volumes that make everything else possible. In 2025 Stone handled roughly R$560 billion of total payment volume¹, a scale that both generates the core revenue and underwrites the company's claim to be a serious payments infrastructure provider rather than a niche player. Scale in payments is a genuine, if incomplete, source of advantage.

The advantage works through fixed costs and data. A payments platform is expensive to build and cheap to run at the margin, so the more volume flows across it, the lower the cost per transaction and the more competitive the pricing Stone can offer while still earning a spread. Volume also produces data — a continuous, granular record of what merchants sell and when — that feeds the underwriting of credit and the tailoring of products. And a proprietary technology stack, reliably processing millions of transactions, is itself a barrier: reliability is invisible when it works and fatal when it doesn't, and small merchants do not forgive an acquirer whose machines go down.

One of the more interesting features of Stone's platform is how it has handled Pix, Brazil's central-bank instant-payment system. Pix is often cast purely as a threat to card acquirers, and there is truth in that. But Stone also processes Pix for its merchants, integrates it into the same terminal and app, and earns from it — turning at least part of the disruptor into another rail it operates. A payments company that offers the merchant every way his customer might want to pay, cards and Pix alike, is more useful than one wedded to a single method.

Still, this is the most commoditized layer of the business, and the moat here is the shallowest. Acquiring is fiercely competitive; take rates grind lower under pressure from the big banks, from Cielo and Rede, and from fellow fintechs; and a large part of Stone's payments revenue comes from advancing merchants their receivables, a business exquisitely sensitive to Brazil's interest rate. Scale keeps Stone in the game and lowers its costs, but it does not confer pricing power the way it might in a less contested market. The payments rails are necessary, valuable, and defensible enough — but they are the foundation of the moat, not its high walls.