Greg Matthews tries to discourage customers at his East Side pharmacy from using credit cards to pay for prescriptions because transaction fees on cards cuts into his already slim profit margin.

"A lady the other day paid her $80 co-pay" on a $120 prescription with a credit card. "I was going to make $3.48," but the credit-card fee took $1.98 so Matthews only made $1.50 on the transaction, he said. The other day a customer was going to pay a $1.05 prescription payment with a credit card, and "I said, 'Forget it.' I just gave it to him" because of the credit-card fee, he said.

Credit-card transaction fees, specifically the interchange fee set by credit- card companies and collected by banks that issue the cards, have become a hot issue with retailers in recent years.

The Merchants Payments Coalition, a national group of retailers, including supermarkets, drug stores, convenience stores and others, has been campaigning to lower the fees. The coalition is pushing for legislation in the U.S. Congress to set up a mechanism to let retailers negotiate card transaction fees with the credit-card companies. Some members of the coalition also are part of pending lawsuits consolidated into one case in a New York federal court alleging price-fixing of fees by MasterCard, Visa and several banks.

"What we want them to do is negotiate with us (merchants) a price fair for their service," said John Motley, senior vice president for the Food and Marketing Institute in Washington, D.C., a member of the coalition. "The reason the issue is so big for us (grocery stores) is the average profit within the food retailing industry in the U.S. is about 1.2 percent." The credit-card fees increase product costs to consumers, he said.

Interchange fees for credit-card transactions average around 2 percent of each transaction dollar amount, Motley said. Supermarkets were offered a low interchange fee years ago to encourage supermarkets to accept cards, but that "rate is now disappearing" because premium credit cards are becoming more prevalent and have a higher fee, he said. Fees on debit cards used with a PIN number average around one-half percent, which is not as much of a problem, he said.

Gasoline retailers earlier this year began complaining about being hurt by rising credit-card fee costs because customers were charging larger amounts due to rising fuel prices. MasterCard and Visa made adjustments in fee charges for fuel retailers, the companies said in statements issued this year.

Last year, $42 billion in interchange fees were collected, and this year that number is projected to grow to almost $49 billion, Motley said. That is a 16.7-percent increase. Only a small portion of the fees go for transaction costs, he said.

Visa and MasterCard, the nation's two largest credit-card companies, said the companies each set their own card interchange rates, but they receive no revenue from interchange fees.

The interchange rate is what the merchant's bank pays to the cardholder's bank for taking on the risk, said Denise Dunckel, a Washington, D.C.-based spokeswoman for Visa. "Visa makes its money from contracts with banks," she said.

Sharon Gamsin, a spokeswoman for MasterCard's headquarters in the New York City areas, told the El Paso Times in May that MasterCard makes its money from fees it charges banks that issue cards.

The interchange fee is part of a merchant discount fee, which is negotiated between the merchant and its bank for credit-card and debit-card transactions, according to information from MasterCard.

The interchange rate is set high enough for banks to have an incentive to issue credit cards and low enough to encourage businesses to accept the cards, the credit-card companies said.

"I think merchants are getting a good value for what they pay for. The alternative (cash or checks) costs more" to handle," said Linda Echard, president and CEO of ICBA Bancard in Washington, D.C., an Independent Community Bankers of America subsidiary that provides credit-card services to community banks. The interchange and merchant fees are important revenue sources that allow banks to stay in the credit-card business, she said.

In Australia, where the government stepped in and reduced interchange rates, the number of cards being issued has decreased, Echard said. A MasterCard statement said Australian credit- cardholders are now also paying higher interest rates and fees because of the decrease in interchange rates.