CME Group Equity Index futures contracts users may roll their futures positions from one quarterly futures contract month (e.g.. June) to the next quarterly futures contract month (e.g.. September) at any time they choose.
However, the trading floor convention is to roll the expiring quarterly futures contract month eight calendar days before the contract expires for most of our Equity Index futures contracts. This is known as the Rollover date. Note that Nikkei 225 contracts historically have a Rollover date of the Monday before expiration.
For these, the Rollover date determines what contract month is listed for trading during the CME Globex session.
If the Rollover date is Thursday, December 13, 2012 for the S&P 500 futures contract, the CME Globex session beginning that evening (at 3:30 p.m. Chicago time /CT) will list the Mar 2013 contract for trading and the Dec 2012 contract would no longer be available to trade on CME Globex. On the trading floor, the Mar 2013 contract would become the lead month beginning at 8:30 a.m. on Thursday, December 13, 2012.
Roll dates for the upcoming listed Equity Index quarterly cycle futures contracts: