The laptop was taken from an employee's locked car in a public parking lot, Ameriprise said. The financial services firm didn't identify the city where the incident took place, saying that police are still investigating the theft.

Windows and Novell Inc.'s networking applications were password-protected on the laptop, but the data files weren't encrypted as required under company policies, according to an Ameriprise spokesman. He said the employee involved in the incident was fired because of the lack of encryption.

The spokesman added, though, that even having a customer's name and account number wouldn't let an identity thief access an account. At least three other pieces of personal information are needed to do so, he said.