From the IRS website:
Credit Card Loss or Fraudulent Charges
Under the Fair Credit Billing Act, your liability for unauthorized use of your credit card tops out at $50. However, if you report the loss before your credit card is used, the FCBA says you are not responsible for any charges you didn’t authorize. If your credit card number is stolen, but not the card, you are not liable for unauthorized use.
ATM or Debit Card Loss or Fraudulent Transfers
If you report an ATM or debit card missing before someone uses it, the Electronic Fund Transfer Act says you are not responsible for any unauthorized transactions. If someone uses your ATM or debit card before you report it lost or stolen, your liability depends on how quickly it’s reported.
If someone makes unauthorized transactions with your debit card number, but your card is not lost, you’re not liable for those transactions if reported within 60 days of the date your statement was sent to you.
How to protect your Credit and ATM or Debit Cards
* Don’t give out your account number over the phone unless you have initiated the call.
* Keep your account information secure. Never leave it out in the open or write it down anywhere.
* Keep a list of your account numbers, expiration dates, and telephone numbers of each card so you can report a loss quickly. Keep this list is a safe, secure place.
* Never sign a blank charge or debit slip.
* Shred copies, save your receipts and check them against your monthly statements.
* Shred or cut up old cards.
* Open your monthly statements immediately and compare them to your receipts.
Report mistakes and discrepancies immediately.
* Carry only the cards that you need.
How to protect your ATM or Debit Cards
* Memorize your PIN. Don’t carry it in your wallet, purse, or pocket.
* Carefully check your ATM or debit card transactions; the funds will be quickly
transferred out of your checking or other deposit account.
* Frequently check your account activity, especially if you bank online. Report any
discrepancies to your card issuer right away.