Knowledge › Amex vs Visa and Mastercard
American Express vs Visa and Mastercard: what a closed loop changes for a merchant.
TL;DR. Visa and Mastercard sit between two banks: the issuer that holds the cardholder and the acquirer that holds you. American Express is the issuer, the network and, on a direct agreement, the acquirer. That one fact decides the rest: who you actually contract with when you “get all three schemes” from one acquirer (four different answers by country, set out below), who decides a dispute (Amex, with an inquiry first unless it has placed you on Immediate Chargeback), what excess costs (a fee per chargeback above 1%, not an escalating schedule), what fraud costs (Full Recourse: no right to contest), and whether your category is accepted at all.
Who this is for. Merchants processing $100K+ a month deciding whether to accept Amex, moving from OptBlue to a direct agreement, or trying to understand why an Amex dispute runs on different rules from the chargebacks they know.
Same transaction, three rulebooks.
Visa
Open network. Issuer and acquirer are separate banks; you contract with the acquirer. Monitoring: VAMP, fraud reports plus disputes over settled CNP transactions, Excessive at 1.5% and 1,500 events. VAMP guide →
Mastercard
Open network. Same two-bank structure. Monitoring: ECP, chargebacks only over the previous month's transactions, ECM at 100 and 1.5%, fines escalating by month. ECM guide →
American Express
Closed loop. Issuer, network and (direct) acquirer are one company. Inquiry before chargeback by default. Excessive chargeback fee above 1% for three months. Fraud Full Recourse at 0.9% / USD 25K.
You signed with one acquirer and got all three schemes. Here is what actually happened to Amex.
With Visa and Mastercard the acquirer is always your counterparty. With Amex, the same signature routes you down one of four paths depending on the country, and the paperwork tells you which.
US: OptBlue
The acquirer resells Amex, up to USD 3M.
Your acquirer is an OptBlue Participant. It contracts with you, sets your Amex rate the way it sets the others, gives you one statement and one settlement, and pays Amex a wholesale rate behind the scenes while sending the transaction data back to Amex. Eligibility is capped at USD 3 million of Amex volume in a rolling 12 months (since 17 April 2026); above that, Amex moves you onto a direct agreement with Amex pricing and Amex settlement. Online gambling and games of value have no cap but can only be boarded by processors Amex has specifically approved.
Canada
Same model, CAD 1M line.
Processors run Amex direct-settlement programmes: the processor is your counterparty for Amex, settles the funds as your agent after receiving them from Amex, and prices by industry. Once you are a high-volume merchant (CAD 1 million), you move to a direct agreement and Amex sets the pricing.
UK and Europe
The acquirer submits; Amex is the contract.
Your acquirer or PSP is, in Amex's terms, a Processor: a third party you retain, approved by Amex, that obtains authorisations and submits charges. The agreement is with American Express Payment Services, Amex sets the discount rate and Amex pays you, on its own schedule, separately from your Visa and Mastercard settlement. One onboarding form at the acquirer; two contracts and two money flows.
GNS markets
A licensed local bank is the acquirer.
Through Global Network Services, Amex licenses banks outside the US. An Independent Operator issues Amex-branded cards in local currency and also acquires and processes for local merchants, so in those countries the bank really is your Amex acquirer, in the Visa/Mastercard sense. Joint ventures with local partners sign merchants the same way.
In all four, the issuer that decides a dispute is American Express. What changes is who sits between you and it, and whether anyone does.
Five differences that matter at the merchant.
01
Who you contract with.
One of four paths, by country: the acquirer resells Amex under a volume cap (US OptBlue, Canada), the acquirer only submits while you contract and settle with Amex (UK, much of Europe), a licensed local bank is the acquirer (GNS markets), or Amex directly. The section below sets them out. The path decides who prices you, who pays you and who you call when something breaks.
02
Who decides the dispute.
On Visa and Mastercard the issuer disputes and your acquirer represents you under scheme rules. On Amex the issuer is the network; there is no third party between you and the company that holds the cardholder. The inquiry step exists because of that: it is Amex asking you before Amex decides.
03
Inquiry first, unless it is not.
Amex normally sends an inquiry before a chargeback, which is your chance to resolve it. On its Immediate Chargeback programme you get no inquiry; on Partial Immediate Chargeback, none below a dollar amount. Amex can place a merchant on either for its own reasons.
04
A fee, not a schedule.
Above a 1% monthly chargeback ratio for three consecutive months, Amex charges a fee per chargeback above the 1% line, recalculated monthly. No months-in-programme escalation, no minimum count. Simpler than VAMP or ECM, and it starts at a lower volume than either.
05
Fraud Full Recourse.
Fraud ratio of 0.9% with USD 25,000 in fraud, or 1.8% with USD 50,000. Once enrolled, fraud chargebacks are yours automatically: no evidence, no contest, no SafeKey liability shift. Three consecutive months under the low tier to exit. Amex can also enrol a merchant that repeatedly fails to answer inquiries.
06
Whether you are accepted at all.
Amex decides which categories it takes, and there is no second Amex acquirer to ask. Its US merchant rules prohibit internet gambling, virtual currency and foreign-exchange bureaus; OptBlue participants cannot board gambling, forex or crypto at all, and regulated online gambling and games of value go only through processors Amex has specifically approved. Where Amex is available, treat it as a separate decision on the numbers, outside the two-acquirer design that protects the rest of your volume.
A single-rail decision, made on the numbers.
We look at what Amex would add (volume, approval, average ticket) against what it costs (pricing, dispute handling with no acquirer in between, exposure to Full Recourse in your category), and whether it is available to you at all. Then we keep the resilience work where it works: two acquirers on Visa and Mastercard, routing by market, a reserve priced on history.
Amex is worth accepting when the numbers say so. It is not a hedge, because there is nothing to hedge it with.
What does it mean that Amex is a closed loop?
Visa and Mastercard are networks between two banks: the issuer that holds the cardholder and the acquirer that holds you. American Express issues the card, runs the network and, for merchants on a direct agreement, acquires the transaction. One company on every side of the payment except yours. Every difference below follows from that: who you contract with, who decides a dispute, and who decides whether your category is accepted.
We signed one agreement with our acquirer and got all three schemes. So who is our Amex counterparty?
It depends on the country, and the answer is on the paperwork. In the US, under OptBlue, the acquirer is: it contracts with you, prices Amex like any other brand, and settles it with the rest, up to USD 3 million of Amex volume in a rolling 12 months (the threshold since 17 April 2026), after which Amex takes you onto a direct agreement. Canada works the same way through processors' direct-settlement programmes, with a CAD 1 million line. In the UK and much of Europe the model is different: the acquirer is a Processor that obtains authorisations and submits transactions, but the agreement is with American Express Payment Services, Amex sets the discount rate and Amex pays you, separately from your Visa and Mastercard settlement. And in markets where Amex has licensed a local bank as an Independent Operator, that bank issues the cards and acquires the merchants, so it really is your acquirer. One signature, but the money and the contract follow one of those four paths.
What is OptBlue exactly?
Amex's US programme for acquiring through third-party processors. The processor (an OptBlue Participant) contracts with the merchant, determines the merchant's pricing and gives it one statement and one settlement for all brands; behind the scenes the processor pays Amex a wholesale rate and sends the transaction data back so Amex keeps its closed loop. Eligibility is capped at USD 3 million in Amex charge volume per rolling 12 months for most industries. Online gambling and games of value are a special case: no volume cap, but only processors Amex has specifically approved and certified may board them, with a minimum of USD 1 million in volume for games of value.
How do Amex disputes differ from Visa and Mastercard chargebacks?
Amex normally sends an inquiry before a chargeback, which is a chance to resolve it with the cardholder's issuer, which is Amex. Merchants placed on its Immediate Chargeback programme get no inquiry; on Partial Immediate Chargeback, none below a dollar amount. Amex can place you on either. Because the issuer is also the network, there is no separate scheme arbitration between two banks; Amex decides.
Does Amex have a monitoring programme like VAMP or ECM?
Not in the same form. Amex applies an excessive chargeback fee: once the monthly chargeback ratio (chargebacks net of reversals over gross charges net of credits) exceeds 1% for three consecutive months, a fee per chargeback above the 1% line, recalculated monthly, until you drop under. No escalation by month in a programme, no 1,500-event floor; the mechanism is simpler and starts sooner. Visa and Mastercard rules: /problems/vamp-thresholds and /problems/mastercard-excessive-chargeback.
What is Fraud Full Recourse?
Amex's fraud programme. Thresholds: a fraud ratio of 0.9% with at least USD 25,000 in fraud (low tier) or 1.8% with USD 50,000 (high tier). Once enrolled, fraud chargebacks are charged to you automatically with no right to contest and no SafeKey liability shift. Exit is three consecutive months under the low tier. Amex can also enrol a merchant at its discretion, for example for repeatedly failing to answer inquiries.
Is Amex available in high-risk categories?
Mostly not, and this time it is written down. Amex's own US merchant rules list internet gambling sites, virtual currency purchases and foreign-exchange bureaus among prohibited merchants, and OptBlue participants' prohibited lists add gambling, foreign exchange and crypto outright, so an iGaming, crypto or CFD merchant cannot get Amex through a regular acquirer in the US. The one carve-out is regulated online gambling and games of value, which Amex allows only through processors it has specifically approved and certified. Outside the US, Amex Payment Services decides the same question itself. Where Amex is available at all, decide on the numbers: the volume it brings, the approval it adds, and the dispute handling it costs.
Does any of this change how we build the acquiring stack?
Amex sits outside the two-acquirer logic that protects Visa and Mastercard volume: you cannot add a second Amex acquirer. Treat it as a single-rail decision, decide it on the numbers, and keep the resilience work on the two open networks, where it works. Multi-rail design: /knowledge/multi-rail.
How is Milestone paid for this?
By the acquirer or PSP you end up using, as a commission on volume. No fee to you for a review. We place with whichever of ~30 providers underwrites your vertical knowingly, so we have no reason to push one.
VAMP thresholds
Visa's combined ratio, with calculator.
Mastercard ECM
Previous-month formula and the fine schedule, with calculator.
Multi-rail
A second path for the volume that can have one.
Deciding whether to accept Amex?
Tell us your vertical, volume and current acquirer. We tell you within one business day whether it is available to you, on which terms, and whether the numbers justify it. No fee for the review.