The U.S. Federal Trade Commission estimates that 27.3 million Americans have been victims of identity theft in the last five years, including 9.9 million last year–and the number of new cases appears to be growing.

Identity theft last year cost businesses and banks about $47.6 billion and consumers an estimated $5 billion. The Fair Credit Billing Act limits the liability due to fraud to $50 per card if the creditor is notified within 60 days of the first bill containing fraud.

“Check your credit reports religiously,” says Liz Pulliam Weston, author of Your Credit Score: How to Fix, Improve, and Protect the 3-Digit Number that Shapes Your Financial Future. “Many people discover that they’ve been the victim of identity theft only after they’ve been turned down for a loan or the interest rates on the credit cards go up. Experts used to advise consumers to check their credit report once per year, but now it’s wise to check all three credit reporting agencies twice per year.”

In many cases, thieves open an account under a stolen identity, run up thousands of dollars in fraudulent charges and have the bill sent to a phony address. It’s never paid and that can wreck the victim’s credit rating. Regional and major banks provide security and aggressive identity theft programs, including J.P. Morgan Chase, Bank of America, Wells Fargo and Citigroup.

In 1988, the U.S. Congress passed the Identity Theft and Assumption Deterrence Act making the unlawful use of another person’s identity punishable by up to 15 years in prison. However, some studies suggest that identity thieves have a one in 700 chance of being caught by federal authorities. That means it’s up to you to protect yourself by securing your computer, account numbers and hard copy receipts. Here’s how.

As a child, your mother told you not to accept candy from strangers. As an adult, the variation on the theme is not to download files or click on links from strangers. Opening an unfamiliar file could hijack your records.

7 Ways here.