The fees on Visa/MasterCard in the EU are capped at 0.2% for debit cards, 0.3% for credit cards.
American Express (and all the other schemes where the issuer is also the acquirer, i.e. Diners Club) aren’t capped.
The 0.3% cap however did kill Amex’s licensing model where they let other banks around Europe issue their cards, so they simply withdrew from those, as 0.3% is not enough to pay for the rewards.
Note that this is just interchange. Payment processors still charge merchants whatever they damn please.
American Express (and all the other schemes where the issuer is also the acquirer, i.e. Diners Club) aren’t capped.
The 0.3% cap however did kill Amex’s licensing model where they let other banks around Europe issue their cards, so they simply withdrew from those, as 0.3% is not enough to pay for the rewards.
Note that this is just interchange. Payment processors still charge merchants whatever they damn please.