What is a Card Network?

A card network — also known as a card scheme or card brand — is the company that operates the payment rails linking card issuers (banks) to merchants and their acquirers. Visa, Mastercard, American Express, and Discover are the four global networks, with JCB, UnionPay, and RuPay covering Japan, China, and India respectively. Card networks set the technical standards (EMV, 3-D Secure), the chargeback rules, and the interchange fee ranges. They don't usually take credit risk themselves — that sits with the issuing bank.

If you've ever wondered who actually runs the wires that carry a card payment from a terminal to a bank and back, the answer is a card network. The terms card scheme and card brand mean the same thing — Europe and the UK lean towards "scheme," North America leans towards "network," and the marketing teams call it a "brand." We use them interchangeably here, and we link out to our card scheme entry for the regulatory framing if that's the angle you need.

The four global networks (and a few you should know about)

There are four card networks with global reach: Visa, Mastercard, American Express, and Discover. Visa and Mastercard between them carry the vast majority of card payments worldwide. Amex sits behind those two by volume but punches above its weight in higher-spend corporate and travel segments. Discover is mostly a US story.

Then there are the regional giants. JCB is Japan's home network and is widely accepted across Asia. UnionPay is China's domestic network and is now the largest card network in the world by issued cards (well over 9 billion at last count) — though most of those cards rarely leave China. RuPay is India's domestic network, built by the National Payments Corporation of India to reduce reliance on Visa and Mastercard.

Open-loop vs closed-loop: two very different business models

Card networks fall into two camps, and the difference matters once you start looking at fees and merchant economics.

Visa and Mastercard run open-loop (or "four-party") networks. They don't issue cards themselves and they don't sign up merchants. They license banks to do both jobs and charge a network fee on every transaction that crosses their rails. Four parties end up in each transaction: the cardholder, the issuing bank, the merchant, and the acquiring bank. This model scales because thousands of banks can plug in.

American Express and Discover historically run closed-loop (or "three-party") networks. The network itself is the issuer and, in many cases, the acquirer too. That gives Amex tighter control over the customer experience and lets it capture more of the economics per transaction — which is why Amex fees are typically higher and why some smaller merchants don't accept it. The trade-off is reach: open-loop networks are accepted in more places.

What a card network actually does

Beyond running the message-routing infrastructure, the network's job is to set the rules of the game. That includes:

• Technical standards — EMV chip specs, contactless protocols, 3-D Secure, tokenisation frameworks
• Operating rules — how brand marks must be displayed, what counts as a valid authorisation, how merchant categories are coded
• Dispute handling — chargeback reason codes, evidence requirements, timelines, arbitration when issuer and acquirer disagree
• Interchange ranges — the fee bands that flow from acquirer to issuer on every transaction
• Compliance enforcement — networks are founding members of the PCI Security Standards Council and require all participants to meet PCI DSS

The thing networks usually don't do is take credit risk. If a cardholder defaults, the issuing bank wears the loss. The network's revenue comes from network fees and assessments on transaction volume, not from lending.

Networks, interchange, and what merchants actually pay

Interchange is set by the network but paid by the acquirer to the issuer on every transaction. In the UK and EU, interchange on consumer cards is capped by regulation at 0.2% for debit and 0.3% for credit. Scheme fees — what Visa and Mastercard charge on top — aren't capped, and they've been climbing steadily, which is why merchants have been pushing back through the Payment Systems Regulator.

For card-not-present transactions like phone payments, the rates are higher than for chip-and-PIN. Networks treat CNP as higher-risk because the cardholder isn't physically present and the issuer can't verify a chip. That's where descoping technology earns its keep — strong handling of the card capture step keeps fraud rates down and keeps you in the better interchange categories.

Why this matters if you take payments over the phone

Three practical things follow from your card network choice when you're processing telephone payments: which cards your gateway can accept, the interchange tier you'll pay (CNP rates differ between Visa, Mastercard, and Amex), and the chargeback rules that apply when a customer disputes a transaction. If you're a UK contact centre processing Visa and Mastercard mostly, your fees will look very different from a luxury hotel taking a lot of Amex corporate cards.