World leaders cheer Supreme Court tariff ruling — but businesses must still navigate 'murky waters'

• The ruling primarily focused on reciprocal tariffs but leaves much of existing bilateral agreements, like the U.K.'s May 2025 deal with 10% broad levies and carve-outs for steel, aluminum, cars and pharmaceuticals, largely unaffected
• Trade bodies warn businesses still face 'murky waters' as the President retains 'other options at his disposal' to reimpose tariffs through alternative legal mechanisms
• Key questions remain unresolved, including how U.S. importers can reclaim levies already paid and whether exporters can receive refunds for tariffs collected under the now-invalidated policy

Market Summary: Supreme Court Strikes Down Trump Tariffs

Key Developments

The U.S. Supreme Court ruled 6-3 against President Trump's far-reaching tariff regime, determining that existing law "does not authorize the President to impose tariffs." The decision primarily affects reciprocal tariffs, though significant uncertainty remains about implementation and business impact.

International Response

United Kingdom: A government spokesperson indicated the country would work with Washington to understand implications, noting the U.K. "enjoys the lowest reciprocal tariffs globally." The May 2025 trade deal imposing 10% levies with carve-outs for steel, aluminum, cars, and pharmaceuticals remains largely unaffected.

European Union: The European Commission called for "stability and predictability" for transatlantic businesses, advocating for lower tariffs while seeking clarity on U.S. next steps.

Canada: Minister Dominic LeBlanc stated the ruling "reinforces Canada's position" that tariffs under IEEPA were unjustified.

Switzerland: Swissmem technology association welcomed the decision but cautioned that "today's ruling doesn't win anything yet," warning the administration could invoke alternative laws to legitimize tariffs.

Market Implications

Trade bodies across affected nations emphasized lingering uncertainty despite the ruling. The British Chambers of Commerce noted the decision "does little to clear the murky waters," warning Trump retains "other options at his disposal" for maintaining steel and aluminum tariffs.

Key concerns include:

• Uncertain refund processes for already-paid levies
• Potential alternative legal mechanisms for tariff implementation
• Ongoing negotiations with Vietnam and Brazil
• Need for businesses to navigate continued regulatory ambiguity

The ruling represents a significant legal setback to Trump's trade policy, though practical business impact remains unclear pending administrative response.