Now, a credit card you can market to mini-me.

• Position: Marketing News - Miniature credit cards for key rings - Brief Article

In the never-ending battle to differentiate themselves, credit-card issuers have developed a new gimmick: the miniature credit card. It comes pierced with a hole and is small enough to mount on a key ring.

Bank of America, Charlotte, N.C., offered the product late last year to about 1 million of its Visa cardholders. This year, all, of its Visa cardholders will be allowed to request the mini, which is about half the size of a regular card.

The idea is that the key-ring card will make purchases more convenient. No longer will consumers have to fumble in their wallets or purses to find their plastic. The mini has a magnetized strip that can be swiped, just like a regular one. (Consumers will have to stick with...