Formally the Eurogroup Working Group is a formation or a sub-group of the EFC. Gradually, the EWG "became a key venue for policy debates, reflecting the rise of the Eurogroup as the leading coordination forum of the euro area".[3]
^Uwe Puetter. The European Council and the Council: New intergovernmentalism and institutional change. Chapter 4.5.1 The EFC and the Eurogroup Working Group. Pages 192-195. Oxford University Press. Sep 18, 2014. ISBN9780198716242.