Specific date of trade settlement (SettlementDate) in YYYYMMDD format.
If present, this field overrides SettlType <63>. This field is required if the value of SettlType <63> is "6" (Future) or "8" (Sellers Option). This field must be omitted if the value of SettlType <63> is "7" (When and If Issued)
(expressed in local time at place of settlement)