Learn the domain· 7 min read
The players
A card payment looks like a one-step interaction (tap, beep, done). Under the hood it's a settlement between five+ parties, each owning a slice of the rails. Understanding who's who is essential for understanding which of them gets stuck holding a dispute.
Last reviewed against primary sources on .
The four-party model
Visa, Mastercard, Discover, and most modern networks operate on what the industry calls the four-party(or "four-corners") model. American Express historically ran a three-party model (it acts as both issuer and acquirer) but now operates a hybrid that behaves like four-party for most issuers.
Cardholder
The consumer holding the card. Has statutory dispute rights under Reg E (debit) / Reg Z (credit) in the US, plus the contractual right to dispute under the card network's rules.
Merchant
The business accepting the card. Signs an acceptance agreement with their acquirer that commits them to following the card network's rules — including paying chargebacks on demand.
Issuer
The cardholder's bank. Issues the card, extends credit (or holds the deposit account for debit), bills the cardholder, and represents them in disputes.
Acquirer
The merchant's bank. Processes settlements into the merchant account, debits the merchant when chargebacks arrive, and is on the hook to the network when the merchant can't pay.
The fifth party that doesn't fit the "four-party" name is the network(Visa, Mastercard, etc.). It isn't a participant in the underlying transaction — it's the rails. Networks set the rules every other party agrees to follow, route the messages, and operate the dispute-resolution machinery. They also collect a small per-transaction fee.
Where the money flows
On a happy-path purchase the cardholder hands over an account credential; the merchant's acquirer turns it into a settlement; the issuer pays the acquirer through the network; the cardholder eventually pays the issuer (either by month-end statement, for credit, or by checking-account debit, for debit). Two days, four hops.
- 1Cardholder presents card
- 2Merchant requests authorization through their acquirer / processor
- 3Network routes the request to the issuer
- 4Issuer approves (or declines); funds reserved on the cardholder account
- 5Settlement: issuer pays acquirer (minus interchange); acquirer pays merchant (minus processing fee)
- 6Issuer collects from the cardholder
The merchant's "net" on a credit-card transaction is the gross amount minus three layers: interchange (paid by the acquirer to the issuer, a network-set rate), scheme / network fees(small per-transaction amounts paid to the network), and the acquirer's own processing markup. Total cost runs roughly 1.5–3.5% of the transaction in the US for a card-present purchase, higher for card-not-present and reward cards.
Where a dispute flows
A dispute moves the same money in the opposite direction, but with more parties auditing each step:
- 1Cardholder calls or messages issuer to report a problem
- 2Issuer optionally pre-empts with an RFI / inquiry (informal — funds stay put)
- 3If unresolved, issuer files a formal chargeback through the network
- 4Network debits the acquirer for the disputed amount + a per-case fee
- 5Acquirer debits the merchant; merchant has a fixed window to respond
- 6Merchant either accepts (loss is permanent) or represents with evidence
- 7If represented, the issuer reviews and either upholds or reverses the chargeback
- 8If still unresolved, either side can escalate to pre-arbitration and arbitration
Two more parties you'll see in the wild
Payment processor
The technical service that moves the authorization and settlement messages. A processor can sit on the issuer side, the acquirer side, or both — Stripe, Adyen, Worldpay, Fiserv, and Chase Payment Solutions are all processors (most are also acquirers). Disputes physically arrive in the merchant's processor portal first.
Payment gateway
A lighter abstraction over the processor — handles the merchant-facing API surface (tokenization, hosted checkout, recurring billing) but doesn't directly hold the merchant account. Modern processors increasingly include their own gateway; standalone gateways like Spreedly remain useful when a merchant wants to swap processors without re-integrating.
Who pays what fee?
| Fee | Set by | Paid by | Paid to |
|---|---|---|---|
| Interchange | Network (Visa, Mastercard, …) | Acquirer | Issuer |
| Scheme fee | Network | Acquirer | Network |
| Processing markup | Acquirer / processor | Merchant | Acquirer / processor |
| Chargeback fee | Acquirer (varies; ~$15–$25) | Merchant | Acquirer |
| Arbitration filing fee | Network | Losing party | Network |
Detailed fee numbers (chargeback fees, arbitration fees, monitoring penalties) live in Fees & monitoring programs — they shift more than the underlying flow does.
Sources
- Wikipedia · Four Corners Model for Payment Security — Canonical reference for the four-party model terminology and the role of each participant.
- Marqeta · Demystifying Cards — the Card Payments Ecosystem — Issuer-side overview of the four-party model and the network/processor/gateway split.
- Cryptomathic · The Four Corners Model — Security-engineering view of the four-corners model with explicit message flows.
- Checkout.com · Payment networks explained — Distinction between scheme (network), processor, and gateway; their non-overlapping responsibilities.