WASHINGTON -- Card interchange has gotten more attention as rising fuel prices have both boosted what consumers pay at the pump and what gas stations accepting credit cards must pay in card interchange.

Gas station trade association maintain that gas station operators, particularly independents, mark up their gas 10 to 12 cents per gallon and an average interchange rate of 2%, gas stations have watched card interchange eat into their profits. At $3.00 per gallon, a station will pay six cents per gallon in card interchange, but at $4.00 card interchange rises to 8 cents per gallon. In California, where the average price of a gallon gas has hit $4.59, the interchange price is just over 9 cents per gallon.

Gas station owners say the already high prices for gas effectively prevent them from raising prices to cover the interchange cost since consumers will shun stations with as little as penny per gallon difference over what consumers believe to be the lowest price.