Some of Wall Streets tried-and-true currency strategies arent working anymore, and its baffling even the most seasoned traders.

Before President Donald Trump s policies sent the dollar plunging, investors could reliably use a number of indicators to figure out how to trade. Europe cuts interest rates? Sell euros. Markets look jittery? Buy dollars. Oil prices spike? Time to snap up currencies from commodity exporters.

华尔街一些屡试不爽的货币策略如今已不再奏效，甚至连经验最丰富的交易员也对此感到困惑。

在唐纳德·特朗普总统的政策导致美元暴跌之前，投资者可以依靠一系列指标来判断交易策略。欧洲降息？卖出欧元。市场动荡？买入美元。油价飙升？是时候抢购大宗商品出口国的货币了。