Type: char
Unique identifier for Order as assigned by broker. Uniqueness must be guaranteed within a single trading day. Firms which accept multi-day orders should consider embedding a date within the OrderID (37) field to assure uniqueness across days.
Added in protocol FIX.2.7
See in: FIX.4.1, FIX.4.2, FIX.4.3, FIX.4.4, FIX.5.0, FIX.5.0SP1, FIX.5.0SP2, FIX.5.0SP2 EP240.