Exports to the United States, Germany's largest trading partner, fell by 7.7 percent compared to April to 12.1 billion euros, federal statistics office Destatis said.
The drop left German exports to the United States at their lowest level since March 2022, came after the initial April announcement by Trump of sweeping "Liberation Day" tariffs.
The punitive reciprocal rates which could see EU exports hit with a flat 20 percent tariff were first suspended until July 9th, before Washington extended the pause till August 1st.
Overall, Germany exported a total of 129.4 billion euros' worth of goods in May, a drop of 1.4 percent on the previous month.
Analysts surveyed by financial data firm FactSet had expected the trade barometer to stagnate.
ING bank analyst Carsten Brzeski said May's fall likely reflected a reversal of earlier "frontloading" after American customers had rushed to get orders in before announced tariffs could take effect.
"This effect has now dissipated," he said, adding that "the risk of (more) tariffs hangs like a sword of Damocles over German and European exporters".
The White House on Monday said it had sent letters to more than a dozen countries detailing the tariffs they would face if they did not reach new trade agreements with Washington by August 1st.
Ongoing trade tensions threaten new pain for export powerhouse Germany, whose economy is already reeling from high production costs and intense Chinese competition in sectors from cars to machine tools.
German Chancellor Friedrich Merz last week called on the EU to strike a "quick and simple" bargain with the United States, saying Germany's "key industries" needed clarity.
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