Getting that info from the card companies is impossible. I've just had an arguement with Amex about this. I made some purchases in the US when the exchange rate was around $1.44 - $1.45 to £1. The rate used by Amex was $1.40. This is the same rate I got for cash at my bank!! They gave me some flannel abut exchange rate fluctuations and they used the internationally accepted Reuters rate but he still could not explain a 4 - 5 cent difference.