'This particular employee had legitimate business reasons to have these files,' Connolly said, but the employee failed to use required processes to encrypt the data. 'What shouldn't have happened is the information shouldn't have been removed from the company's offices without the proper data security.'

The employee, who broke written company policies, was fired due to the incident, Connolly said.

Notification letters about the data theft went out to affected customers and advisors via U.S. Mail beginning last Saturday, he said. It took company workers several weeks to recreate the files that are missing, then it took additional time to cross-reference the names, account numbers or Social Security numbers to find the addresses and other information needed to send out the letters, he said.

There are no indications that any of the data has been used improperly, Connolly said.

'A name and that internal Ameriprise account number are not enough information to do anything' with a customer's account, he said. 'It's not even close.'