In traveling in Russia I noticed exchange rates at banks were significantly less than I was charged on my Marriott Visa card. I raised this issue with the consumer protection agency and Chase sent me a massive contract as to there card details. When I asked them about the exchange rate they indicated this was contained in an agreement with VISA which they did not disclose. The formula as to how exchange rates are determined is still a mystery. For all those who are excited about no transaction fees I can only suggest the banks and credit card companies have a more onerous, nontransparent cost . I Russia the delta was 12-15%.