Most UK businesses never really choose which card networks to accept. If you take payments through a provider like SumUp, Square or Zettle, Visa, Mastercard and American Express all arrive bundled at one flat rate, so there is no separate Amex decision and no Amex premium to worry about. The choice only becomes real if you hold a direct merchant account and set your own rates, which is more common once your jobs run into the thousands. If that is you, the differences between the networks are worth understanding, because most of them come down to how American Express is built.
Rates were checked in June 2026 and pricing changes, so confirm current figures before you rely on them. This is general information about how card payments work, not financial or legal advice.
How the networks are built differently
Visa and Mastercard are networks, not banks. They do not issue your customer's card and they do not hold your money. Four separate companies sit in every Visa or Mastercard payment: the cardholder, the bank that issued their card, the bank that runs your merchant account, called the acquirer, and the network itself. This is an open loop, or a four-party model.
American Express, on a direct account, is built the other way. Amex issues the customer's card, runs the network, and runs your merchant account. One company sits in every seat. This is a closed loop, or a three-party model.
The four-party model is not just a technicality, because each of those separate companies acts as a buffer. The published interchange table is a price you can check, because it is set by a party that is not your acquirer. The customer's own bank decides a dispute in the first instance, and the network sits above it as a final stage, because they are different companies. Take those separate companies away, as the closed loop does, and you take the buffers away with them. The rest of this guide is about what that means in practice.
The price you cannot see
Visa and Mastercard publish their interchange, and you can look it up. UK consumer debit interchange is capped by law at 0.2%, with a 50p per-transaction cap, and consumer credit at 0.3%, for UK-to-UK payments, and both networks publish the full schedules. So you can check the number and hold your provider to it.
Those same published tables also show where your real cost often sits, which is worth knowing. Consumer cards are capped, but business and corporate cards are not, and on a payment link, which counts as card-not-present, they run far higher. Visa's published schedule (April 2025) puts a business debit card at 1.15%, a business credit card at 1.65%, and a corporate or purchasing card at 1.85%, rising to 1.90% on the top business credit tier. On a £50,000 payment from a client's corporate Visa, that is about £925 in interchange alone, before scheme fees or your provider's margin. For many businesses, the card that costs the most is not American Express at all. It is an ordinary company card. The point for now is that the published tables let you see it.
American Express publishes nothing. Because it is its own network there is no interchange to publish, and Amex does not publish the discount rate it charges merchants either. Its own UK merchant page calls its pricing "competitive and transparent" and then shows no figure at all, directing you to call its team for a quote. Independent estimates of a UK direct Amex rate sit somewhere around 1.7% to 3.5%, but they are third-party guesses, and they disagree with each other precisely because there is no published number to anchor them.
The practical effect is simple. On every other network you can compare what you are quoted against a public figure. On American Express you cannot, because the figure does not exist in public. The one card that tends to cost a merchant the most is also the only one whose price you cannot look up.
To be fair to the open-loop networks, their transparency is only partial. The interchange is published, but a second layer called scheme fees, paid to Visa and Mastercard themselves, is not published in plain terms and has been rising. The Payment Systems Regulator found in its 2025 market review that Visa and Mastercard raised scheme and processing fees by at least 25% in real terms between 2017 and 2023, costing UK businesses at least £170 million a year more. So the honest line is not that Visa and Mastercard are open books. It is that they publish and cap the consumer interchange, while American Express publishes no merchant price at all.
Its own referee
When a payment is disputed, the structure decides who judges it.
On Visa and Mastercard, a dispute travels between separate companies. The customer raises it with their own bank. That bank, not the network, makes the first decision. If you disagree, there is a further round, and then a final stage of network arbitration where Visa or Mastercard rules. The first-round decider is the customer's own bank, and there is an independent stage above it.
On a direct American Express account, every one of those roles is the same company. Amex issued the card, Amex is the network, Amex runs your account, and Amex decides the dispute. There is no separate bank in the middle and there is no arbitration stage. You get a single response, within 20 days, and that is the end of it.
The Financial Ombudsman Service has put the point in its own words, in a decision about an Amex dispute, describing "a dispute resolution scheme operated by the companies which run the card networks, which in this case is also American Express."
This describes the structure. It is not a claim that you are more likely to lose, and we will not put a number on that, because the published figures on who wins disputes are thin, come mostly from companies that sell chargeback services, and do not agree with each other. The point that stands without any number is structural. With the open loop there is an independent company deciding the first round and a separate stage above it. With the closed loop there is neither. On a small payment that is a small thing. On a finished job worth tens of thousands, where a single disputed stage payment can be the difference between profit and loss, one response in 20 days with no independent appeal is a real difference.
What you carry yourself
The two points above are really the same point. The closed loop removes the independent parties, and those parties were doing work that protected you. With the open loop, the published interchange checks the price for you, the customer's bank checks the dispute for you, and the arbitration stage checks both of them. With American Express, that work does not disappear. It moves to you.
In practice, on a direct Amex account, that means reading Amex's own operating guide rather than relying on a shared, published scheme rulebook. It means documenting every job tightly, because there is no independent stage to catch a thin case. It means your only real leverage in a dispute is to stop accepting the card, because you cannot switch to a different Amex acquirer the way you can move between Visa and Mastercard acquirers. And it means the same company can hold a reserve of your money while it also judges your dispute. None of that is or improper. It is simply what the structure asks of you, and it is diligence that, on the open-loop networks, the banks share.
Who funds the rewards
Card rewards are paid for by the merchant, not the customer. On Visa and Mastercard, the rewards on a premium card are funded out of the interchange you pay, which is part of why premium and commercial cards cost you more. On American Express, the rewards are funded out of the discount rate you pay. Either way, the points and the cashback the cardholder enjoys are a cost to you, not a benefit to you. It is a merchant cost dressed as a customer perk.
There is one genuine argument on the other side, and it is fair to state it plainly. American Express cardholders do, on average, spend more, and a minority of customers prefer to pay on Amex. Whether that matters to your business depends on how many of your customers would actually pay by Amex and walk away if they could not. For most small businesses serving private customers, that number is very low, because Visa and Mastercard together are more than 95% of UK card payments. For businesses whose clients are companies running expenses through corporate Amex cards, it carries real weight, and that is exactly the case where accepting Amex earns its keep.
Section 75, and why charge cards matter
One protection applies only to consumer credit cards. Under Section 75 of the Consumer Credit Act, for anything costing more than £100 and up to £30,000 paid on a consumer credit card, the card issuer is jointly liable with you for the work. Two things are worth knowing. It does not apply to debit cards, and it does not apply to charge cards, and a number of American Express cards are charge cards rather than credit cards. And above £30,000 it does not apply at all, so on a large project only the dispute process is in play, which brings you back to the structure above.
Where American Express genuinely does well
It is only fair to say what Amex does well, because for some businesses it tips the balance. Its pricing, once you have a quote, is simple: a single flat discount rate, and by its own terms no setup costs and no monthly account fees, which is cleaner than the stack of terminal, gateway and minimum-charge fees that some acquirers add. Disputes are also less frequent on Amex than on Visa and Mastercard, which is fairly put down to an affluent, lower-fraud customer base rather than any structural advantage for the merchant, but the practical effect is still fewer disputes to handle. And as noted above, its cardholders do spend more on average, which is a real benefit if your customers are the kind who carry and prefer the card. None of this cancels out the structure described earlier. It sits alongside it, and for a business with the right customer base it can be the deciding point in favour of accepting the card.
So should you accept American Express?
If you take payments through a flat-rate provider such as SumUp, Square or Zettle, Amex is already bundled at the same rate as every other card. There is no separate cost, and nothing in the sections above changes for you, because a separate provider sits between you and Amex. Accept it and move on.
If you hold a direct merchant account and your work is mostly for private customers, the premium is real but the number of customers who would actually leave is small, so it is a fine-margin decision and it is yours to make.
If you hold a direct account and a meaningful share of your clients are businesses paying on corporate Amex, this is where accepting Amex has the most force, and also, fairly, where the cost gap against an expensive corporate Visa or Mastercard is often smallest. This is the segment where the answer is most often yes.
What to do whichever cards you accept
Ask your provider for interchange-plus pricing, sometimes called cost-plus, once your volumes justify it, so you can see the published interchange separately from your provider's margin. Ask for your card-mix breakdown, because the most useful thing you can know is how much of your turnover runs on uncapped business and corporate cards. For many businesses that, not the Amex question, is the single largest controllable cost, and a flat blended rate hides it. And document every job: a written contract, signed stage sign-offs, dated photographs, and written confirmation that the work was completed. It is your defence on every network, and it is the only defence that does not depend on which network the customer used, or on whether there is an independent referee.
Common questions
Is American Express more expensive for merchants than Visa or Mastercard?
On consumer credit cards, usually yes, because Visa and Mastercard consumer interchange is capped at 0.3% while a direct Amex rate is commonly estimated at 1.7% to 3.5%. On a flat-rate provider there is no difference, because Amex is bundled at the same rate. And against an expensive corporate Visa or Mastercard, the gap can be small or none. Amex also does not publish its merchant rates, so you cannot compare without a quote.
Why does American Express not publish its merchant fees?
Because it runs a closed loop and sets its discount rate by private contract rather than through a published interchange table. Its UK merchant page describes the pricing as competitive and transparent but shows no figure and asks you to request a quote.
How is an Amex dispute different from a Visa or Mastercard chargeback?
On Visa and Mastercard the customer's own bank decides the dispute first and there is a network arbitration stage above it. On a direct Amex account the same company issues the card, runs the network and decides the dispute, there is no arbitration stage, and you get a single response within 20 days.
Does Section 75 protection apply to American Express?
It applies to consumer credit cards of any network for purchases over £100 and up to £30,000. It does not apply to debit cards or to charge cards, and several Amex cards are charge cards, so check the specific card type.
Should a small business accept American Express?
If you use a flat-rate provider, yes, because it costs you nothing extra. If you hold a direct account and serve mostly private customers, it is a fine-margin choice. If your clients are businesses paying on corporate Amex, accepting it is usually worth it.
Sources and a note on accuracy
Figures are taken from Visa's UK domestic interchange schedule (April 2025), the Payment Systems Regulator's 2025 market review, American Express's own UK merchant pages, the Financial Ombudsman Service, and UK Finance, all checked in June 2026, with merchant rate ranges drawn from third-party estimates where no published figure exists. Card pricing and rules change. Confirm current figures and check your own card and merchant agreements before relying on them. This guide is general information and is not financial or legal advice.
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