Options trading at the Chicago Board Options Exchange (CBOE) was delayed Thursday, due to an unspecified “internal issue” that has now been resolved, the company says.

The CBOE experienced a trading outage today that saw trading delayed until noon local time. After the session closed, the parent company, CBOE Holdings, Inc., issued a statement indicating that “a system issue” delayed the opening of trading.

“The malfunction that impacted CBOE was an internal systems issue and not the result of any outside influence. The issue, which affected validation of certain orders and the communication of cancel/fill reports, has been corrected,” it said.

While CBOE trading was disrupted between 8:30 and 11:50 CT noon, trading at C2 Options Exchange, CBOE Futures Exchange, and CBOE Stock Exchange opened as scheduled.