Morgan Stanley has written to 34,000 customers warning them that their personal financial details may have been stolen while in transit to the New York State Department of Taxation and Finance.
The data - including names addresses, account and tax ID numbers and some social security numbers - was shipped on two password-protected, but unencrypted CD-ROMs.
The package containing the CDs was intact when it arrived at its destination, but the discs were missing by the time the parcel reached the desk of the intended recipient.
Jim Wiggins, a Morgan Stanley Smith Barney spokesman told Credit.com that the brokerage had failed to unearth the missing discs after a two-week investigation. The firm then notified customers and offered to pay for a year of credit-monitoring service to customers who received letters warning that their Social Security numbers were among the data.