MasterCard

MasterCard and Visa said Friday that they had notified issuers of its credit cards of a potential breach of the security of customer accounts. Visa blamed a third company for the error.

It has been 63 years since Frank McNamara invented the credit card, and those little pieces of plastic are everywhere. But now, a groundbreaking new technology could upend the industry he created.

Visa said Wednesday that its fiscal first-quarter profit rose 16 percent, as card use rose both in the U.S. and overseas. The San Francisco-based payments processor posted a notable 10 percent increase in U.S. credit card use. But debit card use rose just 6 percent. That's the slowest debit card growth rate in more than a year, and comes during the first three-month period that new rules were in place to limit the fees retailers pay to accept the cards.

Sometimes it pays to wait; sometimes it doesn't. Just ask the roughly 10 million cardholders who were part of the Foreign Currency Conversion Fee Antitrust class action lawsuit settlement. After a decade of legal wrangling, the settlement funds are finally being disbursed -- but a suit this large can dilute even $336 million.

Washington's efforts at financial reform keep having strange and unintended consequences. In response to a law that was meant to lower excessive debit card transaction fees on merchants, Visa and Mastercard found a way to raise the fees on a host of small businesses.

New and higher debit card fees may not be enough to satiate the big banks. Financial institutions looking for revenue are now eyeing another source: Selling your debit-card transaction data to marketers. So which is worth more to you: The deals such targeted advertising will bring, or your privacy?

It's been awfully quiet on the earnings front in recent weeks, and there's a reason: This is the time of year when accountants are nailing down the financials for the fiscal quarters that ended in September. Later this week, the conference calls will begin trickling in, and then it will be a deluge of quarterly reports until early November.