The case alleged that card companies overcharged when converting foreign transactions into dollars and didn't disclose all fees. It looked at currency conversion fees - often up to 3 percent of the transaction value - on credit card and debit card as well as cards used to tap automated teller machines.
People who held cards that were branded by Visa, MasterCard or Diners Club and issued by major American banks, including JPMorgan Chase and Co. or Citigroup Inc., are part of the class.
A $336 million settlement in the case, which had been brought in 2001, was announced in July 2006 and affirmed by a court in November 2006.
The defendants denied any wrongdoing, but said they settled to avoid the expense and uncertainty of litigation.
Ruthanne Gordon, an attorney with Berger & Montague PC, a Philadelphia law firm that handled the case, said she expects millions of people to respond to the mailing.
Lawyer David Langer said that the firm has created a Web site at www.ccfsettlement.com with details of who is eligible for a payment and how to file a claim.www.mercurynews.com