CBOE Holdings Inc. opened at $32.80 on June 15, a 13% premium to its $29 initial public offering price announced the day before. The IPO raised $278 million for the exchange based on its 9.6 million share portion of the IPO.

CBOE still is awaiting resolution over long-term legal battles with the International Securities Exchange (ISE).

In 2006, ISE filed two lawsuits against CBOE: one questioning CBOE’s exclusive trading licenses to list options on stock market benchmarks and the other alleging that CBOE’s hybrid trading system violated three ISE patents.

Cook County Circuit court Judge William O. Maki is expected to rule on the exclusive license suit on July 8.

One patent suit is still in court and in May, ISE filed for damages of $300 million as part of its opposition to a CBOE motion for summary judgment.