Payments-to-Banking Cross-SellNarrow moat

The engine that turns a payments company into a bank is cross-sell, and Stone's is working. The card machine is the wedge: it gives Stone a relationship with the merchant and a front-row view of his sales, which makes offering him a banking account a natural next step rather than a cold pitch. The results show it — banking active clients reached about 3.7 million by the end of 2025¹, up roughly a fifth in a year, a base built largely by converting existing payments merchants.

The appeal to the merchant is simplicity: keep the money where it already lands. When card receipts settle straight into a Stone account the merchant can spend, pay suppliers, and manage from the same app that runs his terminal, the friction of using a separate bank starts to look pointless. For Stone, each conversion is worth far more than the banking fees alone, because it moves the customer from a loose payments arrangement toward a primary financial relationship — and it gathers the deposits that fund everything else.

The difficulty is that everyone wants this same small business banking relationship. Nubank, Mercado Pago, and the incumbents are all chasing it, and a banking account is not, by itself, a deep moat — balances can move with a few taps. Stone's edge is that it starts from ownership of the payment flow, which its digital-only rivals must win separately. Whether that edge holds depends on execution: keep the service good and the app sticky, and the payments wedge keeps converting into banking relationships; let either slip, and the cross-sell that looks so natural today gets a great deal harder.