The CME Group specifications require that any butter traded on the spot (cash) market or delivered as part of a futures (physical delivery) contract settlement beginning March 1 of every year "...shall not have been produced or stored prior to December 1 of the previous year." Therefore, the supply of butter eligible to be traded at the CME Group declines significantly every year between the last trading day in February and the first trading day in March. This specification for butter traded at the CME Group has been in effect since March 2001. For complete details on the specifications for all dairy contracts traded at the CME Group, visit its website at www.cmegroup.com.