UnderlyingID <2874> field
FIX 5.0 SP2 EP271
Unique identifier for the underlying instrument within the context of a message.
The UnderlyingID <2874> can be referenced by other fields, for example UnderlyingRefID (tbd2841) and SideUnderlyingRefID <2863>, from other components . The scope of uniqueness is agreed upon between counterparties.