I was trying to decide which card was best to use overseas, and started testing the currency conversion with my CITI Thank-You Premier VISA. I made a charge in EUR on Aug.18, and waited for it to post. Indeed, there was no separate exchange fee. However, CITI applied the exchange rate of 1.2489. The official market exchange rate on Aug.18 was 1.2334. Since that date was on a weekend, I also looked up the highest rate during Aug. 18-20 --> it was still about 1.236. Just a few weeks ago, I used my Citi ATM card with no foreign exchange fees overseas. In that case, the conversion was at the exact market rate. So now I'm puzzled why the VISA CC rate is 1.26% above the market. I inquired with a Citi CS rep, and he did not know the answer. I checked with VISA International -- they charge a fee for customer service, and advised that I would be better off going back to Citi with that question. So is there a reasonable explanation for the rate discrepancy or is this a hidden fee? Has anyone checked the rates charged by MasterCard?