Why is the euro not appreciating against the dollar despite the euro zone’s external surplus and the United States’ external deficit?

From 2002 to 2008, the United States’ growing external deficit led the dollar to depreciate sharply against the euro. Today, however, the euro is not appreciating against the dollar despite the United States’ external deficit and the euro zone’s external surplus. Why? An analysis of capital flows shows that the yield spread between the dollar and the euro is sufficient to give rise to capital flows from the euro zone to the United States, which is preventing an appreciation of the euro. Thanks to its zero interest rates, the euro is being used to fund carry trade positions in other currencies, especially the dollar . This is not efficient from the euro zone’s viewpoint.