This is not true. All Mastercard and Visa cards charge a rate that is specified my Mastercard and Visa on a daily basis. I've been tracking this rate for a few months now, and it's consistently been awfully close to the rate I find on xe.com.

The CARD Act of 2009 mandated that credit card issuing companies clearly describe the fees associated with foreign transactions.

Visa/Mastercard charge a cross border origination fee of 0.80%. However many credit cards (all cards by Captial One for example) waive this fee, and do not charge any fee of their on on top of this.