Your billing zip code, or credit card postal code, is the five-digit number on the bottom right, which in this sample is 90210. This would be the zip code associated with your billing address. It ...

Why do merchants sometimes ask us for our ZIP code when we buy something? I recently visited the Mob Museum in Las Vegas, an interesting addition to Sin City’s attractions. I paid my admission ...

Reporting from San Francisco — In a case watched closely by merchants, the state Supreme Court ruled unanimously that California retailers may no longer collect ZIP Codes from credit card ...

And some credit cards, like American Express, prompt retailers to ask for a ZIP code as a form of fraud protection.