Europe's handling of the influx of migrants over the past six months has been widely criticized, with some economists forecasting rising unemployment in some regions. Others say that long-term employment will get a boost from the number of skilled workers that have found refuge in Europe. And with the Continent's aging population, especially in Northern Europe, some say migrants could help boost productivity there.
Separately, the migrant crisis has polarized politics in Europe, with a resurgence among populist parties that some say could lead to a weaker and more fractious EU. At this point, however, analysts generally agree that it's too early to analyze exactly how migrants will alter Europe's economic landscape.
The other big risk that Patterson mentions — a Brexit — is seen as a major headwind for the European Union and the U.K. economy. Citizens in the United Kingdom are to vote sometime before the end of 2017 in a referendum on whether Britain should leave the EU. (The United Kingdom never joined the euro zone currency bloc.)
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If the vote is "yes," some U.K. strategists say business investment could decline and major financial institutions could move their headquarters out of the country. Sectors that are most vulnerable to a downside in the event of an exit include the banks and automobile industry, according to Marc Ostwald, a strategist at ADM Investor Services. Ostwald cautions investors not to jump to conclusions, however, as it really comes down to the terms of any British/EU negotiation. Such talks could take up to two years to finalize. Still, Brexit remains a high risk.