The German chamber of commerce said on Wednesday that US import tariffs on steel could trigger a trade war with major trading partners, which analysts say could cut growth in Europe's largest economy by up to one percentage point.
US President Donald Trump said on Tuesday he was considering a range of options to address steel and aluminium imports that he said were unfairly hurting US producers, including tariffs and quotas.
Trump's comments were the strongest signal in months that he will take at least some action to restrict imports of the two metals, delivering on his election pledge to put America first and protect US workers from increased foreign competition.
But Martin Wansleben, managing director of Germany's DIHK Chambers of Industry and Commerce, said the introduction of tariffs would eventually burden US consumers through higher prices and could trigger a worldwide trade war.
"With the proposal of new import tariffs, the US government is undermining the positive investment incentives from its tax reform," Wansleben said.
The US is Germany's most important export destination after the rest of the European Union, and exports still account for roughly 40% of German economic output.
But any import tariffs will eventually hit all US companies that rely on intermediaries or capital goods from abroad, Wansleben said.
"As appealing as the tax relief from the recent US tax reform may be, new import barriers raise prices and disrupt international production chains," Wansleben warned.
The growing threat of protectionist measures comes as the German economy enjoys a consumer-led upswing boosted by a rebound in exports and company investment.
Data released earlier on Wednesday showed German gross domestic product (GDP) expanded by a calendar-adjusted 2.5% in 2017.
The government expects the consumer-led upswing to continue this year, forecasting 2.4% growth. The DIHK Chambers of Industry and Commerce was more optimistic, projecting 2.7% growth in 2018.
"If Trump really decides to impose import tariffs, much depends on how the major trading partners of the United States will respond," Berenberg economist Florian Hense said.
"A protectionist race and an end of our liberal world trade order would be fatal, especially for Germany's export-dependent economy," Hense added.
In the worst-case scenario of a full-blown trade war, import tariffs and other barriers could chop as much as one%age point off German economic output, he estimated.
"But we view this scenario as rather unlikely," Hense said. The more likely scenario would be that the US imposes only some restrictions, limited to a few industrial sectors, he said.
This means that individual companies such as German steel company Salzgitter could suffer from import duties but not German exporters as a whole, Hense said.
"In this scenario, the damage would amount to 0.1 or 0.2 percentage points of overall economic growth," he estimated.
"The upswing in Germany will continue, especially as it is now largely driven by the domestic economy."