The US Office of the Comptroller of the Currency has confessed that a former employee downloaded many files onto two removable thumb drives before his retirement and when contacted was unable to locate or return the thumb drives to the agency.

The downloads occurred in November 2015 and were first detected last month during an OCC-initiated retrospective review of employee downloads to removable media that occurred over the last two years. The OCC began the review in August as part of a policy preventing employees from downloading information and data to removable media without the approval of their supervisors. That retrospective review is still underway. The review identified a significant change in download patterns by a former employee in the week before his retirement. The regulator told the Treasury Department.

The OCC says that the breach "involved controlled unclassified information, including privacy information; the devices containing the information are not recoverable; and the incident involved the unauthorised removal of more than 10,000 records."