How do banks and credit card companies know that fraudulent charges occurred on your card?

It is unusual when your card is used in a city/country different to where it is ordinarily used or when it is being used for large amounts, or any amounts that vary from your usual spending. They have spending trends for each card and they check dodgy transactions accordingly.

If it keeps happening then yes someone has your details and is essentially stealing from you. Inform your bank and get a new card issued. They usually have their own inquiry procedures to determine whether your claim is genuine. I think go sooner than later if this keeps happening.

When I was in college, my dad added me to his account and I had a separate card. Sometimes we’d make purchases in different states within minutes and he’d get a call.

I have had calls from my credit card company querying transactions because they took place abroad or because they were for large amounts. They also cancelled my card last week because it had been used in a machine they knew had been compromised.

They watch for trends and if your card isn’t used in a manner that is familar with them, ie, large purchases, out of your normal shopping state, they will call and confirm it’s actually the cardholder using the card.

I had them question a hotel in Chicago since I had bought gas in San Francisco that morning. The annoying thing was I had charged my plane ticket a week before on the same card.

If the spending is atypical. Multiple very large purchases in a few hours, or charges around the country or different countries. You basically over time establish your normal patterns, and when it goes outside of those patterns it is a red flag. When I travel out of country I usually call my credit card ahead of time to let them know.

You can always change your credit card number if you feel someone might have it. Just call your credit card customer service, choose the lost or stolen option, and tell the person you have a suspicion, and want a new number. They will send you out a new one right away. Just remember temporarily you will not be able to charge, you will have to wait to receive the card in the mail and activate it.

My patterns of credit card use are so erratic that I have been called multiple times about them. I think that there is a geographical area where they expect you to be, and if you are spending money outside of it, they assume that someone has stolen your credit card.

I’ve had a hold placed on my card automatically because I myself was spending like a drunken sailor one day, with several major purchases at several different retail outlets in several towns. When I got to the last place (the supermarket), the card was refused, and I had to use the ATM card instead.

When I got home there was a message on my answering machine from the credit card company stating exactly what had happened, and with a callback number (direct to a real person) to clear it up instantly. Very helpful.

I’m abroad now and I forgot to tell my bank before I left. When I got here, I started using the ATM machine and they started lowering my daily limit till I called them. Things are better these days than they were in the past. Since cell phones are everywhere, they can call you and question a charge right away instead of putting a hold on your card. Sadly, international calls can still be a problem and banks don’t want to email you even to say “please call us.” Thankfully a letter from the bank reached someone who did scanned it up and sent it over.

@zenvelo I don’t know if the credit card company can see the details (date, destination, etc…) of a plane ticket you bought. Even if they can see it (in the sense of the data is available) I’m not sure I’d want them to look at it. There’s only so much data I want them to see…

@roundsquare I see the flight details on my credit card bill!

@zenvelo Interesting. I guess the system doesn’t look at that. Maybe they’d rather be careful then assume you caught the flight.