This section provides the conventions for UDS instrument expiration and extension given the possible leg configurations and order types.

A UDS will remain an active contract on CME Globex until the end of the current trading week or until the leg with the shortest maturity expires, whichever comes first. If there is a working Good Till Cancel (GTC) order on the Combo after the close on Friday, the expiration will be extended an additional week. This extension will repeat as many times as necessary until the earliest leg expires.

CME Globex assigns the expiration date and time as either the earliest leg expiration OR the end of the current trading week, whichever occurs first.

Midweek Tag 48-SecurityID Re-Use

UDS instruments can be deleted midweek. When this occurs, CME Globex sends a Security Definition message (tag 35=d) with the instruction to delete the instrument with tag 980-SecurityUpdateAction=D (delete).

Covered and CBOT Treasury Futures Tail Spreads UDS Expiration

For additional information on UDS expiration, see the following:

• UDS - Extension for GTC or GTD Orders

• UDS - Extension for Recursive Spreads