The Chicago Mercantile Exchange (CME) has set the size of its secondary offering at 1.4 million shares, just months after the futures and options exchange became the first US bourse to float.

Morgan Stanley has won the mandate to lead the secondary offering after leading the CME's initial public offering with UBS Warburg (now UBS Investment Bank). Morgan Stanley will act as the bookrunning manager with UBS Investment Bank as joint lead manager.