Published: Feb 06, 2011 12:43 AM EST
Updated: Feb 05, 2011 9:43 PM EST

NEW YORK (AP) - The company that runs the Nasdaq stock market says hackers penetrated a service that handles confidential communications between board members of public companies. They say it appears no customer information was compromised.
Nasdaq OMX Group Inc. says the hacking attempts did not affect its trading systems. Nasdaq is the largest electronic securities trading market in the U.S. with more than 2,800 listed companies.

About 300 companies use Nasdaq's Directors Desk service.

A federal official tells The Associated Press that authorities are trying to identify the hackers, who broke into the systems repeatedly over more than a year. The motive is unknown.

The official spoke on condition of anonymity because the inquiry by the FBI and Secret Service is continuing.

(Copyright 2011 by The Associated Press.  All Rights Reserved.)