[19] One recent meta-study finds that being part of the monetary union can explain at least half of the overall increase in business cycle correlation among euro area countries since 1999. [20] Countries’ participation in value chains nonetheless varies, with some more exposed to agglomeration effects than others.
[21] This underlines the need to continue deepening and broadening the single market, so that all member states are well integrated into the European value chain and share in the common business cycle. But just as in the US, euro area countries are still exposed to idiosyncratic shocks due to their trade  structures, as we see in Germany today.