(Undated) -- Roughly 600-thousand Citibank customers learned the financial giant inadvertently exposed their Social Security numbers earlier this year. In a letter, the bank said it believes there is quote, "little or no risk" to the affected customers. The Social Security numbers were printed on the bottom edge of envelopes which contained year-end tax statements. Citibank blamed a processing error which resulted in the Social Security numbers, along with "a string of other numbers and letters all resembling a mail routing number" being printed.
