Card networks

Its role in the system

The most common way to pay in a shop and online. A card network is neither a bank nor money, but a set of rules and a switch that in seconds connects the buyer's bank with the seller's bank: it asks whether the money is there, records the purchase, and in the evening works out who owes whom. The money itself then moves between banks through the interbank systems.

Functions

1. Authorisation — a second after the card is tapped, the issuing bank checks funds, limits and signs of fraud and answers yes or no.
2. Clearing and settlement — the network gathers all the day's purchases, calculates the banks' mutual obligations net of fees and passes the totals on for final settlement.
3. Rules and standards — who is responsible for what, how to dispute a purchase (chargeback), technical security standards: the EMV chip, contactless, tokenisation, 3-D Secure for online payments. Chargeback is worth understanding precisely: it is a rule of the card scheme itself, not a law, it exists only inside the card world, and it is time-limited — usually a hundred and twenty days from the transaction.
4. Issuing — the issuing bank gives cards to clients and sets limits, credit terms and rewards.
5. Acquiring — the acquiring bank or a payment company signs up merchants, provides terminals and online payment, collects the money for them and answers for the merchants' good faith.

What makes it special

• The four-party model: buyer — issuing bank — network — acquiring bank — merchant (🌍 Visa, Mastercard). The three-party model: the network is itself the issuer and the acquirer (🇺🇸 American Express). 🇯🇵 Japan's JCB is a hybrid: at home it both issues cards and signs up shops, while abroad, instead of building its own terminal network, it agrees reciprocal acceptance — since 2006 JCB cards have been served by the American Discover network, and Discover cards in Japan are accepted by JCB.
• Who earns what: on every purchase the merchant pays a fee to the acquirer; the largest part of it is the interchange fee, which the acquirer passes to the issuer, plus the network's own charges. That is also where card cashback comes from — merchants fund it.
• Regulation of fees: interchange is a permanent subject of competition disputes. 🇪🇺 since 2015 consumer cards have been capped at 0.2% (debit) and 0.3% (credit); 🇺🇸 the cap applies only to the debit cards of large banks (Regulation II, whose validity is currently being contested in court).
• Who oversees them: central banks as overseers of significant payment systems, competition authorities over fees, and the industry body PCI SSC over the card data security standard (PCI DSS). 🇪🇺 national schemes such as Cartes Bancaires in France and Girocard in Germany operate alongside the global networks. 🇪🇺 Strong customer authentication has applied since 2019: a payment must be confirmed by two of three independent factors — something you know, something you have, something you are — and the code is tied to that exact amount and payee. The effect is measurable: in a joint ECB and EBA report, card fraud was seventeen times higher where the payee sat outside the European Economic Area and the rule does not apply.
• National schemes and geopolitics: access to the global networks is a question of sovereignty, so countries build schemes of their own. 🇨🇳 UnionPay grew on the rule that terminals in mainland China must accept it, and then expanded outwards: its cards are accepted in roughly 180 countries and territories and issued in several dozen countries outside China. After 2014 🇷🇺 moved domestic processing onto its own system, and 🇮🇳 and 🇧🇷 are building national schemes as a counterweight to Visa and Mastercard. For a shop, accepting a "foreign" card is a question of a deal between networks, not of new hardware.
• Cards linked to a crypto wallet: from the outside it is an ordinary card. At the moment of authorisation the wallet sells the required amount of crypto at a rate that includes its own mark-up, and ordinary money pays for the purchase — the network sees a normal transaction. The card itself is issued by a licensed institution with scheme membership: 🇺🇸 the Coinbase Card is issued by Pathward, N.A. under a licence from Visa and run on Marqeta's processing, while 🇪🇺 the Crypto.com card is issued by Malta's Foris MT under a financial institution licence. The weak point is that issuer: in June 2020 the UK regulator suspended Wirecard Card Solutions for several days and Crypto.com and TenX cards in Europe stopped working, and Binance's card programme in the European Economic Area closed on 20 December 2023 when its issuer Contis stopped issuing. The networks are moving this way too: Visa lets issuers and acquirers settle with it in stablecoins (April 2026: nine blockchains, an annualised run rate of about 7 billion dollars and more than 130 stablecoin-linked card programmes in over 50 countries).

Why it matters

When cards stop working, shops grind to a halt within minutes — most people have no cash on them. An outage of a network, or its withdrawal from a country, is visible to the whole economy immediately.

Links to other zones · 10

• Anti-Money LaunderingAnti-Money Laundering watches Card networks: transaction monitoring, sanctions against schemes and banks, and control of front merchants used for prohibited payments.
• Banking & Credit InstitutionsThe issuing bank gives out the card, carries the credit risk on the credit limit and earns interchange on every purchase; the acquiring bank signs up the merchant and takes the merchant's risk — if it fails holding prepayments, the acquirer repays buyers through chargebacks.
• Corporations & Corporate FinanceCorporations & Corporate Finance pay for Card networks: merchants take acquiring, handle chargebacks and in effect fund shoppers' cashback, while corporate cards carry travel costs.
• Digital paymentsMost of what looks like Digital payments — Apple Pay, Google Pay, a Stripe or Adyen checkout — is a Card networks transaction wrapped in a token; the wallet changes the interface, not the rails underneath.
• FX marketWhen a card pays in another currency, the conversion is done not by the customer's bank but by the network at its own rate; the issuer adds its mark-up on top, and the terminal may offer to charge "in your own currency" (DCC) at a worse rate.
• Households & IndividualsHouseholds & Individuals use Card networks as their main means of daily payment and consumer credit — credit cards and instalments.
• Interbank systemsCard networks only work out who owes whom; the netted amounts between banks are actually paid in central bank money through the national RTGS system run by Interbank systems.
• International transfersCard networks make International transfers invisible to the shopper: the network converts the currency and settles between banks in different countries by itself, while the margin added to the exchange rate stays a hidden part of the price.
• Regulation & SupervisionCard networks meet Regulation & Supervision as interchange caps from competition law and as consumer protection rules.
• Technology & InfrastructureCard networks depend on Technology & Infrastructure for processing, tokenisation, real-time anti-fraud models and the PCI DSS security standard.

Regulation and supervision

Careers in this zone · 6

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