Updated: May 29, 2013 7:01AM
The Chicago Board Options Exchange delayed its opening Thursday morning after its trading system suffered an unspecified glitch.
The delay at the nation’s largest options market locked traders out of some key contracts used to hedge stock investments or to speculate on market direction.
Widely used options contract dealing with the Standard & Poor’s stock indexes and the VIX volatility index are listed exclusively at the CBOE.
The system malfunction was a “software issue” and not related to hacking, though the cause remained unclear as the exchange reopened up again, according to CBOE spokeswoman Gail Osten.
Trading was back online shortly before noon.
Early Thursday, CBOE announced that some users were having trouble downloading from the site.
The CBOE usually opens at 8:30 a.m. Chicago time.
Contributing: Diana Novak and Grid reporter David Roeder