American Express

Also called Amex, AmEx, American Express OptBlue

A card network that is also the issuing bank and, historically, the acquirer — which is why Amex costs more and behaves differently.

What it is

American Express is structurally different from Visa and Mastercard. It is a closed-loop or three-party network: for most of its consumer cards, Amex issues the card, holds the cardholder relationship, and historically also acquired the merchant directly. There is no separate issuing bank collecting interchange, because Amex is the issuer. That is why Amex discount rates have traditionally been quoted as a single all-in number rather than interchange plus a markup. For small merchants, the practical reality in 2026 is OptBlue. Under OptBlue, an acquirer or ISO can board Amex on the same merchant account, the same statement and the same deposit schedule as Visa and Mastercard, for merchants under a volume threshold. Elavon, for example, explicitly names Amex OptBlue in its published agent program alongside PIN debit, EBT and corporate cards. OptBlue is why most small merchants no longer have a separate Amex agreement, a separate deposit, and a separate 800 number. What OptBlue does not do is make Amex cheap. Published small-business rate cards routinely price Amex higher than Visa and Mastercard on the same transaction — SpotOn, for instance, has published a materially higher Amex rate than its card-present Visa and Mastercard rate on the same plan — a gap of roughly three quarters of a percentage point gap is typical, not exceptional.

Why it matters to your business

In Southwest Florida, Amex mix is not a rounding error. Seasonal visitors, corporate travel and higher-income households push Amex share above national averages at many Lee and Collier restaurants, and if your effective rate looks worse than your neighbor's, card mix is the first thing to check before you blame your processor. Because OptBlue rates are set by your acquirer rather than by Amex, your Amex rate is a negotiable line item in a way many merchants assume it isn't. If your statement shows a flat Amex rate materially above your Visa and Mastercard effective rate, that gap is worth asking about explicitly.

Where it gets contested

The long-standing merchant complaint about Amex is cost, and the long-standing merchant counter-complaint is that Amex customers spend more. Both are supportable. Amex's higher discount rate is real and shows up on every published rate card. Amex's argument — higher average tickets, affluent cardholders, and a corporate/T&E franchise that a restaurant in Naples genuinely benefits from during season — is also real, and the merchants who drop Amex often discover the traffic mattered. The second, quieter issue is anti-steering. Amex fought and won a Supreme Court case in 2018 defending its rules restricting merchants from steering customers away from Amex at the point of sale. Merchants argued those rules suppressed competition on acceptance cost. The Court disagreed, holding that the two-sided nature of the card market had to be considered as a whole. It remains a live grievance in merchant advocacy circles, and it means Amex sits outside much of the steering relief the 2026 Visa/Mastercard settlement provides. The practical complaint from small merchants under OptBlue is simpler and less dramatic: OptBlue pricing is set by the acquirer, so the same merchant can pay very different Amex rates depending entirely on which ISO boarded them.

How to check it yourself

On your next statement, separate Amex volume from Visa/Mastercard volume and compute the effective rate on each (total fees for that brand divided by that brand's volume). Then ask your processor whether you are on OptBlue and what markup they are adding on top of the Amex wholesale rate. Get the answer in writing.

Receipts

Claims above that are checkable, with where to check them. Published so you do not have to take anyone's word for it.

SpotOn's published POS Essentials rate card prices Amex materially above card-present Visa and Mastercard
spoton.com ↗
Elavon's published agent program includes American Express OptBlue acceptance alongside major card types, PIN debit, EBT and corporate/purchasing cards
elavon.com ↗
American Express operates its own network and issuing business
americanexpress.com ↗