Type: Qty

Quantity open for further execution. If the OrdStatus (39) is Canceled, DoneForTheDay, Expired, Calculated, or Rejected (in which case the order is no longer active) then LeavesQty could be 0, otherwise LeavesQty = OrderQty (38) – CumQty (14).
(Prior to FIX 4.2 this field was of type int)

Added in protocol FIX.4.1

See in: FIX.4.1, FIX.4.2, FIX.4.3, FIX.4.4, FIX.5.0, FIX.5.0SP1, FIX.5.0SP2.