Q&A: What should cardholders do?

Q: What should I do if I think my information may be compromised?

A: Check your credit card statements carefully. If you see suspicious charges, report the activity to your credit card companies and call Target at 1-866-852-8680.

You can report cases of identity theft to law enforcement or the Federal Trade Commission. For more information about identity theft, check the FTC's website at www.consumer.gov/idtheft or call the FTC at 1-877- IDTHEFT (1-877-438-4338).

Q: Who pays if there are fraudulent charges on my account?

A: In most cases, consumers aren't on the hook for fraudulent charges. Credit card companies are often able to flag the charges and shut down your card. If that doesn't happen, the card issuer generally will strip charges you claim are fraudulent off your card immediately. And it will be Target that ­ultimately compensates the banks and credit card companies.

Q: Why is the Secret Service investigating?

A: While it's most famous for protecting the president, the Secret Service also is responsible for protecting the nation's financial infrastructure and it has broad jurisdiction over many financial crimes. It isn't uncommon for the agency to investigate major thefts involving credit card information.

A: While debit cards offer many of the same perks as credit cards, they often don't come with the same kind of fraud protections. Those card holders may have a tougher time getting their money back if their number is stolen.

Q: How can I protect myself?

A: Using only cash, you can only lose what you're carrying, though admittedly many people may not feel safe walking around with a wad of bills in their pocket. Since credit card companies don't hold consumers liable for charges they don't make, the worst thing consumers usually have to deal with is the hassle of getting a new credit card.

Q: How can breaches be ­prevented?

A: An easy way would be to eliminate the use of easily cloned magnetic strip cards and upgrade to the kind of microchip technology used in other parts of the world. But banks have pushed back against the idea, because the microchip cards cost significantly more than the magnetic strip version and changing over all the country's ATMs could drive the total costs into the billions of ­dollars.