Details stored on the CD included names, addresses, account numbers and PEP values. It was sent to HMRC in late April and outsourced for processing to a contractor, but has now disappeared.
HMRC has apologised for the loss. The number of investors affected is unreported although they have been notified by UBS Laing & Cruickshank.
The disclosure follows a string of high profile privacy breaches in the US, including the loss in transit of computer back-up tapes holding information on up to 600,000 Time Warner current and former emplyees, and the disappearance of backup tapes containing the credit card information of 1.2 million federal workers by Bank of America.
