In most states, by law, all but the last four digits of your credit card number need to be disguised on the CUSTOMER COPY only. Meaning that on the MERCHANT COPY it is still legal to print the full number. Most credit card identity theft happens from the Merchant copy of the card (unfortunately by a dishonest person inside of the merchant). That’s why i cross out all but the last four digits on the Merchant copy as well. Many merchants have started disguising it on both copies, but if you look at the Merchant copy of your next ten credit card receipts, you will notice that not all of them do this yet.

As for the social security number, the last four digits are used extensively as a PIN number or password. Identity thieves collect information in small bits and slowly accumulate it until it’s worth something. For example, with your last four digits, birth year and your place of birth, I could go to a website and with about 70% confidence find out the first 5 digits (which are assigned geographically). For example, if you were born in Colorado in the late sixties, there is a 70% chance that your SSN starts with 523-0X-XXXX. I hope this helps.

How can a store receipt make me vulnerable to identity theft when it carries only the last four digits of my credit card.

I have the same question for my social security number. If someone asks me only the last four digits of the SSN, how can this be misused. Please elaborate. Thank you very much.