Citibank Exposes Thousands of Customers' Social Security Numbers

According the Chicago Tribune, Citibank mistakingly mailed year-end tax statements to 600,000 customers with their Social Security numbers printed on the outside of the envelope. Citi is blaming the mistake on a "processing error."

The company believes the error produced little to no risk because the numbers were not identified as Social Security numbers. Still, Citi is offering customers the option to enroll in a free, 180-day credit monitoring service.