No points for guessing why.
Nasdaq said in a notice to traders it halted trading on its Nasdaq Options Market, known as NOM, at 10:56 a.m. EDT. The halt came after an alert earlier in the morning that said Nasdaq was investigating problems with the market erroneously canceling some orders….
Nasdaq OMX's other two options exchanges were operating normally, as was the exchange operator's equities market, according to a spokesman. Nasdaq is investigating the issue, he said.
It's not been a great week for Bob Greifeld & Co., beginning with a rare human-error trading problem on Tuesday, followed by the media discovering that it might have been able to prevent it's last really big screw-up had it bothered to do something. So it's going to take it's time to figure this one out.
Nasdaq OMX said Friday it halted trading at 10:36 a.m. Eastern Time and announced at 2:10 p.m. that it would shut down options trading for the rest of the day. Regular stock trading on the Nasdaq Stock Exchange was not affected.
It was unclear when options trading would resume.