Local Currency and Group Currency 
Definition
Local Currency
Local currency for a consolidation unit.
If the local currency is not the same as the group currency, translation from the local currency to the group currency is required.
Group Currency
Currency for a consolidation group.
Structure
Local Currency
The local currency is a property of the
primary consolidation unit. The local currency isGroup Currency
The group currency key is a characteristic in the data basis.
You can have multiple group currencies in a version.
You must always enter the group currency key in reporting. This also applies to reports in the local currency.

The group currency is not a property of the consolidation group.