Citi said the card capability enhances an iPhone app that it launched last year for its retail banking customers.
Using the app, which employs the same user ID and password customers use to access their accounts online at the Citi cards Web site, consumers can check account balances and available credit, details on recent transactions, and the date on which the next payment is due.
Citi has tried a variety of initiatives in the realm of mobile banking and payments. On most handsets, retail banking and card transactions employ different apps.
The company said in December that it was studying its various efforts to determine what banking services people really want to access with their mobile phones, and how to make that happen.
