Cards & Merchant Payments / Learning brief
Cards vs account-to-account rails
Your notes
In simple terms / 01
What this means in plain language
Two ways to pay the same merchant — a card through the four-party model, or a credit transfer straight between bank accounts — compared on parties, the authorisation step, when money actually moves, revocability and disputes, fees, and message standards, with an honest look at when each rail wins.
A card payment and an account-to-account (A2A) transfer solve the same problem with opposite bargains. Cards run the four-party model — cardholder, merchant, acquirer, issuer, with a card scheme between the banks. Authorisation wins the merchant an issuer's promise in seconds, but the money moves later through clearing and settlement, the merchant pays a proportional merchant discount (interchange plus scheme fees plus acquirer margin), and the cardholder keeps a formal dispute right: the chargeback. A2A payments — credit transfers, including instant ones, often started from a 'pay by bank' button — move the money itself, bank to bank, frequently in seconds, at a typically flat and lower cost. But the transfer is effectively final: there is no chargeback, only a recall request that needs the receiving side's cooperation, and it addresses errors rather than disappointment. Cards tend to win where trust is thin, credit matters, or habit rules; A2A tends to win on cost, speed, and finality for invoices, payouts, and trusted relationships. Most merchants sensibly run both.
Key takeaways / 03
Three things to remember
- 01
Cards deliver a promise before the money (authorisation now, settlement later); A2A delivers the money itself, often with instant finality.
- 02
Dispute rights are the sharpest divide: chargebacks exist because card scheme rules create them, while settled credit transfers offer only cooperative recalls for errors.
- 03
Card costs are proportional and fee-laden but buy acceptance, credit, and buyer trust; A2A costs are typically flat and lower but carry no built-in buyer protection.
Practical use cases / 04
Where you would use this
A merchant keeps cards at the counter for walk-in customers but moves wholesale invoices to A2A transfers to escape proportional fees on large amounts.
A marketplace pays its sellers by credit transfer for finality, while accepting cards from buyers who expect dispute protection.
A payments product team weighs a pay-by-bank checkout option, balancing lower cost per transaction against customers' attachment to card habits and chargeback rights.
Worked example / 05
Put the idea into a real situation
Illustrative example (SYNTHETIC / TRAINING ONLY): Demo Coffee Ltd, a fictional merchant, sells a GBP 240.00 espresso machine online. Paid by card over the fictional Cardnet network (standing in for Visa- and Mastercard-style networks), the payment is authorised in seconds by the fictional Bank Alfa; money settles later through Demo Coffee's acquirer, Meridian Bank, which — at an illustrative 1.5% merchant discount — pays out GBP 236.40, and the buyer holds a chargeback right for months of dispute exposure. Paid instead by instant credit transfer from a pay-by-bank button, the GBP 240.00 lands with finality in seconds for an illustrative flat fee of GBP 0.20 — but if the machine arrives dented, the customer's bank can only send a recall request that Demo Coffee may accept or refuse; there is no chargeback. The owner's conclusion is a portfolio, not a winner: cards for first-time online buyers who want protection, A2A for the wholesale customers who reorder every month.
Evidence & review / 07
Evidence & review
Choosing or explaining payment acceptance in markets that have both card acceptance and a credit-transfer rail (for example SEPA). The interchange caps cited apply to consumer cards in the EU under Regulation (EU) 2015/751; other regions and commercial cards differ.
What this brief simplifies: Treats 'account-to-account' as one family even though credit transfers, instant schemes, and open-banking initiation differ in detail. Fee comparisons are directional, not a price list, and dispute rules are summarised at the level of rights rather than scheme time limits. The 0.2%/0.3% consumer interchange caps are quoted from Regulation (EU) 2015/751 as commonly cited; the regulation text could not be re-verified during this authoring pass (environment egress policy), so cap scope details beyond the consumer debit/credit split are deliberately not elaborated.
Sources for this brief2
- 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.