The four-party model
Who does what when a card is used to pay: cardholder, merchant, acquirer, issuer — and the network that sits between them and writes the rules.
L0 Explain simply
An everyday analogy: a card payment is a promise relayed through four hands. Maya Chen taps her card at Demo Coffee Ltd; the coffee shop does not know her bank, and her bank has never heard of the coffee shop. So each side brings its own specialist. The merchant has an acquirer — Meridian Bank — whose job is to collect card money on its behalf; the cardholder has an issuer — Bank Alfa — which gave her the card and holds her account. Between the two banks sits the card network, here called Cardnet, a fictional network standing in for Visa- or Mastercard-style networks. It passes the messages and referees with one shared rulebook, so that any card works at any shop that takes the brand. (SYNTHETIC / TRAINING ONLY — every person and firm named here is fictional.) Four parties and a referee: that is the frame everything else in this domain hangs on.
L1 Core concepts
The four-party model names the roles in most card payments: cardholder, merchant, the merchant's acquirer, and the cardholder's issuer, with the card network between the banks. The acquirer signs up merchants, accepts their card transactions and gets them paid — the business of merchant acquiring. The issuer gave the cardholder the card, holds or extends the money, and decides in seconds whether each payment is approved. The network holds neither account: it routes authorisation messages, clears transactions between the banks, and publishes the scheme rules that every participant contractually accepts. The contrast is the three-party model, where one company is both issuer and acquirer — a closed loop with no interbank step. Many small merchants reach all this through a payment facilitator, which accepts cards under its own acquirer relationship on their behalf.
L2 Practitioner view
In production the four boxes rarely map one-to-one onto four companies. Issuers and acquirers often delegate the technical work: an issuer processor answers authorisation requests against balances and limits on the issuer's behalf, and an acquirer processor runs the merchant-facing connections and batch submissions. The legal roles stay where the licences are — the network licenses its member banks, and the scheme rules bind everyone who touches the transaction — which is why 'who is the acquirer of record?' is a real operational question, not pedantry. Money keeps its own geometry, always one hop at a time along existing relationships: issuer to network side, acquirer to merchant. The fees ride the same hops — an interchange fee from acquirer to issuer, scheme fees from both banks to the network — and later topics price them out. When a payment misbehaves, locating which relationship it broke in (cardholder–issuer, merchant–acquirer, bank–network) is usually the fastest route to who must fix it.
Sources for this topic2
- Market practiceMarch 2003 edition
A glossary of terms used in payments and settlement systems ↗ — CPSS (now CPMI), Bank for International Settlements
Terminology has evolved since this edition; newer CPMI publications refine some definitions.
- Simplified educational illustration
Payments Signal editorial teaching models — Payments Signal
Used wherever diagrams, scenarios, figures, or example values are didactic constructions rather than sourced facts; every such use carries a simplifications disclosure. All people, companies, banks, and list entries in examples are fictional.
Deepest material on this page: L2 — Practitioner view. Where a topic stops short of implementation depth, that is a deliberate coverage decision, not an oversight — see coverage.