Trading on the biggest exchange for financial options resumed Thursday following an outage caused by software problems.

The Chicago Board of Options Exchange failed to open at its regular time of 9:30 a.m. Eastern, then reopened at 12:50 p.m. with trading of options on the Standard & Poor's 500 index, according to CBOE spokesperson Gail Osten.

Trading of other options resumed ten minutes later, according to the CBOE's Twitter feed.

Options give the holder the right, but not the obligation, to buy and sell stocks or other financial assets.

The CBOE is the largest U.S. options exchange. Many of the most frequently-traded stock options are bought and sold on its exchange.