Citigroup said its missing tapes were shipped from Weehawken, New Jersey, on May 2. It said it first learned of a possible problem on May 20 when Experian called to request a tracking number.
The bank said Experian and UPS advised it on May 24 that they could not locate the tapes. Citigroup said it notified the U.S. Secret Service on May 27 after an internal investigation. That agency did not immediately return a call seeking comment.