The Cash App you use to split brunch and the small-business merchant tools sitting inside Square share a single piece of plumbing. One side of the platform brings in millions of consumers who want a free, fast payment app. The other side brings in millions of sellers who want cheap card acceptance. Block earns money on both sides at once. That is a two-sided market in fintech, and according to Federal Reserve payment systems data, those marketplaces now route a meaningful share of US retail flows. This explainer covers how two-sided fintech markets work in the United States, who participates, and why the model is reshaping consumer and business banking at the same time.
The phrase two-sided market is borrowed from economics. It describes a platform whose value to one group depends on participation by a different group. Visa and Mastercard pioneered the structure in the 1960s. Today, US fintechs are running the same playbook with software, and the consumer and business sides are growing at different speeds but for the same reason.
What two-sided markets in fintech actually mean
A two-sided market in fintech is a platform that needs two distinct user groups to be useful and earns revenue from one or both. Payment networks are the textbook example. Cardholders want merchants to accept the card. Merchants want enough cardholders to make acceptance worthwhile. The network sits in the middle, collects fees, and grows by making both sides happy at the same time.
In US fintech the pattern has spread beyond cards. Peer-to-peer payment apps need both senders and receivers. Marketplace lenders need both borrowers and investors. Embedded insurance products need both consumers seeking coverage and merchants who want to offer it inside their checkout. Each of these platforms only works when both sides show up at scale, and the strategic question for the operator is which side to subsidize first.
The economics are different from one-sided businesses. Pricing decisions on a two-sided platform are rarely about cost recovery on a single side. Charging consumers nothing while charging merchants a percentage is the classic pattern. So is the reverse, charging businesses a small flat fee while letting consumers pay nothing. Cross-subsidies are the rule, and the operator’s discipline is how it splits the value created across the two sides.
The US data behind the model
The numbers show how much of US payments now sits in two-sided structures. Bain estimates that around $7 trillion of US transaction value will flow through embedded finance channels in 2026, with platform and infrastructure revenue rising from $21 billion in 2021 to $51 billion this year. Most of those flows live inside two-sided platforms, where the platform brings consumers and businesses together inside a single product surface.
The peer-to-peer payment segment is the most consumer-visible part. Zelle reported $1 trillion in transaction volume in 2024 and continued double-digit growth into 2025. Venmo and Cash App together added tens of millions of active users over the same window. Each is a two-sided platform, and each one’s growth makes the other sides more valuable. Cash App, for instance, makes more money on each consumer once that consumer is also a business customer using Square card readers or invoicing tools.
The Banking-as-a-Service segment shows the business side. Fortune Business Insights projects the US share of the BaaS market at about $8.15 billion in 2026. The BaaS operators are themselves two-sided platforms in the wholesale sense, connecting chartered banks on one side with fintech brands on the other. Each side cares about how many participants are on the other side, and the platform owner’s job is to keep both balanced.
What consumers gain from the model
Two-sided platforms tend to feel free to the consumer side. A peer-to-peer payment is delivered at no cost. A buy-now-pay-later split at checkout adds no fee to the shopper. A debit card from a neobank carries no monthly charge. Those zero-price experiences exist because the platform is collecting from the business side, often as a percentage of transaction value.
The benefit shows up most clearly in speed and convenience. The Clearing House reported a 28 percent year over year increase in RTP volume into early 2026, and FedNow now reaches institutions holding roughly 90 percent of US demand-deposit accounts. Two-sided platforms are typically the first to wire those rails into consumer experiences, which is why a Zelle transfer often beats a traditional ACH by three days even though the underlying bank could in theory move just as fast.
The trade-off is data. Consumers on a two-sided fintech platform are usually paying with attention, history, and inferred intent rather than dollars. The Consumer Financial Protection Bureau’s open banking rule under Section 1033 gives consumers a path to move that data between platforms, which is a structural counterweight to the lock-in two-sided markets can otherwise create. For more on how the disclosure landscape applies to embedded fintech, see TechBullion’s payments coverage.
What it means for US businesses
For businesses the platform is a distribution channel and a cost center at the same time. A small merchant signing up for Square accepts the per-transaction fee because the platform delivers consumer demand that would be hard to reach alone. A SaaS company embedding Stripe inside its checkout gets a payments capability without building a settlement stack. In both cases the business is paying for participation in a network, and the marginal cost of one more transaction is the gross margin trade.
The US small-business segment has adopted the model at an unusually fast pace. Bain’s embedded finance research notes that the platforms most heavily used by US small businesses include vertical software (Shopify, Toast, Mindbody), horizontal software (QuickBooks, Gusto), and horizontal payment networks (Square, Stripe, PayPal). Many small businesses sit on three or four such platforms at once, each functioning as its own two-sided market and each contributing a slice of operating workflow.
The business case is rarely about price alone. A merchant choosing Square over a traditional acquirer often pays slightly more per transaction because the platform also delivers software, hardware, payroll integration, and a working-capital offer pulled from the same data stream. The price on each component is partly a reflection of how much value the other components create. That bundling is itself a two-sided market feature, and the merchant’s economic decision is on the package, not the swipe fee.
What to watch next
Three trends will shape the next phase of two-sided fintech markets in the United States. The first is the spread of vertical platforms. The deepest economics are now in platforms built for a single industry, like restaurants on Toast or fitness studios on Mindbody, where the operator can sell software, payments, lending, and payroll inside one workflow. Pure horizontal payment networks face more competition, while vertical platforms are still building moats.
The second is the regulatory perimeter. The CFPB’s Section 1033 rule, the Federal Trade Commission’s continued focus on unfair pricing, and state-by-state money transmitter rules all shape how two-sided platforms can subsidize one side at the other’s expense. Operators that try to extract too aggressively from the business side now face the prospect of losing merchants to a competitor that uses the same regulatory rails differently.
The third is the role of stablecoins. The Genius Act, signed in July 2025, gave US fintechs a clear federal path to use payment stablecoins inside their products. Visa’s stablecoin program reached a $4.5 billion annualized run rate by January 2026. Two-sided platforms that move money across borders are the most likely first adopters, because stablecoin settlement reduces the cost of running both sides at the same time. The platforms that get this right will be cheaper to run and more profitable, and the consumers and businesses on them will probably never notice the change.
