Despite the remarkable progress made in many emerging and middle-income economies over the last few decades the continuing liberalization in financial markets and the integration into the global financial system these countries remain highly vulnerable to real and financial shocks coming from the U.S. and other advanced economies. Particularly in the aftermath of the financial crisis emerging economies have been subject to rapid buildups and reversals of international capital flows and large real exchange rate fluctuations. This experience is partially responsible for a new debate on the relevance of the open economy policy ‘trilemma’ as applied to emerging market economies (Rey 2013 2015).