The U.S. Securities and Exchange Commission said Thursday it was closely monitoring the situation after problems distributing stock price quotes forced exchange operator Nasdaq OMX Group Inc to halt trading in all of its listed shares.
"We are monitoring the situation and are in close contact with the exchanges," said SEC spokesman John Nester.
All traffic through Nasdaq stopped at 12:14 p.m. EDT. Options trading was also halted.
(Reporting by Sarah N. Lynch; Editing by Lisa Von Ahn)