The academic literature on currency unions often casts the issue in terms of whether member
countries form an “optimum currency area, OCAMundell, 1961; McKinnon, 1963; and Kenen, 1969).
In principle, countries can benefit from a currency union through capital market integration, lower
terms-of-trade volatility and reduced exchange rate fluctuations. Countries with weaker institutions can
import monetary policy credibility (McKinnon, 2004; Tavlas, 1993).
There are also costs, mostly associated with forgoing exchange rate flexibility and monetary policy
autonomy for managing cyclical conditions. To minimize such costs, countries in currency unions would
best have synchronized business cycles and growth patterns, which is typically enhanced by intra-
industry trade (Frankel and Rose, 1998).
In currency unions with incomplete business cycle synchronization, flexible non-monetary
adjustment mechanism are needed: notably price and wage flexibility and cross-border labor mobility.
Risk sharing through integrated financial markets can also help, by diversifying income sources through
cross-country asset holdings (McKinnon, 2004; Mongelli, 2008).
Business cycle synchronization of NMS with the euro area is in general lower than within the euro
area, even though there are differences between countries (Fidrmuc and Korhonen, 2003; Artis et al.,
2004; Darvas and Szapáry, 2005; Van Arle et al. 2008). For Hungary, Poland, and the Czech Republic,
synchronization with the euro area is higher than for the other NMS; and also higher relative to Greece and
Portugal (Fidrmuc and Korhonen, 2006; Rinaldi-Larribe, 2013).
Wage flexibility in the NMS tends to be high while cross-border labor mobility has been increased
(Gruber, 2004; Dao et al. 2014), with substantial outward migration from some NMS in the wake of the
global financial crisis (OECD, 2013):
Wage flexibility. According to Gruber (2004) and Boeri and Garibaldi (2006) NMS tend to have lower
statutory minimum wages, union density rates and more decentralized wage bargaining structure than
the euro areaall pointing to wage flexibility.
Labor mobility. Outward migration in the post-crisis period of 2009-2011mostly was younger and
educated workers, typically finding employment abroad below their skill level (Anacka et al., 2011; Jauer
et al., 2014).
Cross-country risk sharing through financial market integration is low. While prior to the 2008/09
financial crisis, there was some evidence of increasing integration in equity and debt marketssuch as lower
interest rate dispersion and increasing effects of the euro area shocks on NMS equity markets (Cappiello et
al. 2006; Baltzer et al. 2008)these reversed in the wake of the crisis, with higher interest rate spreads
(Pungulescu, 2013) and funding market segmentation along national lines (van Rixtel and Gasperini, 2013).
In addition, cross-border asset holdings tend to be one-directional: euro area banks hold sizeable assets in
NMS, and also FDI and portfolio investment from euro area residents in NMS is much larger than vice versa.
As a result, domestic investment in the NMS is more sensitive to domestic saving than in EU15, and national
consumption is closely correlated with GDP (Pungulescu, 2013).
Overall, while there are significant structural differences and lack of integration with the euro area, for NMS
like the Czech Republic, Hungary, and Poland, this do not seem larger than heterogeneity within the euro
area itself.