Originally Posted by
zyxlsy
I understand they use different rates. But I am curious to know whether it's possible that, at one time, say, Visa rate is better than MC rate, and several days later, Visa rate fluctuates to a position worse than MC rate?
This is very much possible. I find my forex free MC and Amex compete against each other for the best rate when I use my GBP cards in the US. Amex use the rate of the transaction time though I think, whereas MasterCard and Visa use the settlement date.