Originally Posted by
Majuki
Yep, but these are the exceptions more than the rule. I would say AmEx and Discover have a lot more tightly controlled network end-to-end than Visa and MC. If AmEx doesn't want to allow DCC for instance, it's more easily enforceable.
In most countries there are probably more non-amex issued amex network cards than Amex issued cards. 4 Banks in the UK issue American Express cards (Lloyds, TSB, MBNA and Barclaycard). I know Australia is very similar along with several others like Russia, India and Greece.
The main reason there is no DCC on American Express transactions is because American Express is usually the acquirer (for its own transactions only obviously) and the network. It would make no sense to have DCC as American Express makes the foreign transaction fee (off the issuer if not an Amex issued card and usually off the customer if it is an Amex card). American Express would be competing with themselves!