The personal information of 196,000 Hewlett-Packard employees has been put at risk after a laptop containing the data was stolen last week.

Social security numbers, names, addresses and other financial information were on the machine being used by Fidelity Investments, which administers the company’s retirement plans.

Affected staff have been informed of the loss, and the company is monitoring activity in the affected accounts.

Fidelity would not explain why such critical data was on a vulnerable laptop, but has claimed that the information was not in a state that would be easy to use as the program in which it was created had an expired license.

"We have no indication that any of the information's been misused," a Fidelity spokesperson was reported as saying. "We went back and monitored activity in accounts since the theft, and we find nothing to indicate there's any unusual or suspicious activity.''

Only weeks ago, another tech company, McAfee, admitted it had lost personal records relating to 9,000 of its employees, after an auditor left a data CD in the seat-back pocket of an airliner. Again, the data was not encrypted – against all good practice in data security – and was in an accessible form.

The most notorious case of all was that of Choicepoint, which in February 2005 announced that a security breach had allowed the personal details of 145,000 US citizens to fall into the hands of criminals. In that incident the data had been taken directly from a database, a scam that saw Choicepoint fined $10 million by regulators earlier this year.