In a decision that will ripple through the global economy, the top US court struck down Trump's sweeping tariffs imposed under a law meant for use in national emergencies, handing a stinging defeat to the Republican president.
But while many businesses cheered after lengthy legal battles against tariffs, European trade groups, companies and analysts worried the ruling might make trade relations even more messy after hard-struck trade deals in 2025.
"This ruling ... risks creating a boomerang effect, producing further uncertainty and a freeze on orders while operators wait for a clearer regulatory framework," said Paolo Castelletti, secretary-general of Italian wine association UIV.
The US is the top market for Italian wines, with some 1.9 billion euros ($A3.2 billion) in exports in 2024, making up almost a quarter of Italy's total wine shipments globally.
Many firms cautioned that Trump would likely look to other avenues to impose similar tariffs, dulling the benefit of lower levies, while the move could stoke tensions between the US and major trade partners.
Tariff refunds will also be hard to get.
Responding to the ruling, Trump announced new global tariffs of 10 per cent for an initial 150-day period and acknowledged it was not clear if or when there would be any refunds.
Steve Ovara, chair of the International Trade Practice Group at law firm King & Spalding, said companies his firm advised, from large US manufacturers to consumer and technology groups, mostly expected any relief from tariffs to be short-lived.
"The major issue everybody's going to be dealing with for at least the short term is some additional uncertainty," he said.
Wolfgang Grosse Entrup, managing director of German chemicals and pharmaceutical lobby VCI, which represents firms such as BASF, Bayer and Evonik, agreed.
"Anyone who believes this means the tariff conflict is over is mistaken," he said.
"New tariffs based on a different legal basis are possible at any time."
French cosmetics association FEBEA, which has firms such as L'Oreal as members, said it was "very cautious" on the ruling and would watch how the US government responded, including with potential new tariffs.
"We are all used to the twists and turns on this subject of customs duties," said FEBEA secretary-general Emmanuel Guichard.
