Morgan Stanley said it has fired an employee for allegedly stealing and trying to sell financial information about 350,000 clients -- or about 10% of customers at the Wall Street giant's wealth-management arm.
The stolen data included names, account numbers, size of accounts and certain transaction information.
There was no sign that Social Security numbers, passwords or credit-card information were taken, and "no evidence of any economic loss to any client," Morgan Stanley said in a statement Monday.
The employee, who was not identified, was fired late last week, according to a Morgan Stanley official briefed on the matter.
The official said the company had notified law-enforcement authorities, who were conducting a criminal investigation.
Morgan Stanley said it was contacting potentially affected clients and offering to have their accounts monitored for fraud at no charge.
The financial services firm, which manages $2 trillion in assets for clients, said that it began investigating after names and account numbers of about 900 of the customers were "briefly posted on the Internet."
Morgan Stanley didn't disclose further details, but the official said it appeared the employee had posted the information as "samples -- showing off his wares" to entice fraud artists to pay him for more.
"We think this was an attempt to sell the information," said the Morgan Stanley official, who was not authorized to go beyond details in the news release and thus spoke on condition of confidentiality.
"Morgan Stanley takes extremely seriously its responsibility to safeguard client data, and is working with the appropriate authorities to conduct and conclude a thorough investigation of this incident," the company said in its statement.
Clients with questions were asked to call (855) 398-6437 from the United States and Canada or (512) 201-2186 from elsewhere in the world.