Dow Jones & Co., publisher of The Wall Street Journal and other influential financial publications, said Friday it was looking into a report that Russian hackers had used information stolen from its servers to trade on before it became public.
Bloomberg, citing four sources it did not identify, said the FBI, Secret Service and the Securities and Exchange Commission were leading the investigation of the intrusion. The incident was said to be "far more serious" than a data breach disclosed by Dow Jones a week ago, according to the Bloomberg report. Dow Jones CEO William Lewis said last week that his company was the target of a hack that may have exposed the credit and debit card information of "fewer than 3,500 individuals."
In a statement to NBC News on Friday, Dow Jones indicated it was unaware of the broader intrusion.
"To the best of our knowledge, we have received no information from the authorities about any such alleged matter, and we are looking into whether there is any truth whatsoever to this report by a competitor news organization," the statement said.
An FBI spokesperson told NBC News the agency was aware of the Bloomberg report and was looking into it. The U.S. Attorney's Office for the Southern District of New York declined comment.
In addition to the Journal, Dow Jones, a unit of Rupert Murdoch's News Corp, also owns the weekly financial publication Barron's and the online financial news site MarketWatch.
This article originally appeared on NBCNews.com.