Nasdaq and other U.S. exchanges have halted trading in all Nasdaq-listed issues because of a technical problem.
Options trading was also halted, the exchange said.
The Wall Street Journal reported that there was a problem with a data feed that distributes stock price quotes.
“We are monitoring the situation and are in close contact with the exchanges,” said John Nester, a spokesman for the Securities and Exchange Commission.
All traffic through Nasdaq stopped at 11:14 p.m. CDT. Options trading was also halted.
Separately, the CME is investigating data feed problems in the Chicago Board of Trade soy futures complex.
On Tuesday, a series of trades on Nasdaq, CBOE and other exchanges were flagged for review.