The mid-market rates shown in these information services are neither "buy" rates nor "sell" rates. Mid-market rates are derived from mid-point between the buy and sell rates of large-value transactions in the global currency markets.Since "buy rates" and "sell rates" include overheads and profit margins that are set independently by each foreign exchange provider, they will vary depending on who you're talking to, and will always be different than the mid-market rate.