From a letter sent by Yusen Logistics (Americas) to its current and former employees:
On the morning of September 24, 2013, we learned that a password-protected, unencrypted laptop computer issued to a YLA employee was stolen from the employee’s vehicle the night before. The incident was reported to the police and we immediately began a thorough investigation to determine the information that may have been stored on the laptop. Our investigation confirmed that the laptop contained a spreadsheet that included payroll deduction information for current and former YLA employees between July and September 2013. Specifically, the spreadsheet included your name, address, Social Security number, and payroll benefit deduction amount. To date, the computer has not been located.
Pfffft.
You can read the whole notification letter here (pdf).