The Trump administration moved swiftly to impose a sweeping 10% tariff on goods imported from nearly every nation after the U.S. Supreme Court, in a 6-3 decision on Friday, struck down the president's earlier reciprocal tariff authority under the International Emergency Economic Powers Act. A notice published by U.S. Customs and Border Protection late Monday designated the new levies as Temporary Section 122 Duties, applicable for a period of 150 days unless specific exemptions are granted.

The president had initially signaled on social media that the rate would be raised to 15%, writing that he was elevating the tariff "to the fully allowed, and legally tested, 15% level." However, the customs notice that took effect Tuesday specified a 10% ad valorem duty, leaving markets uncertain about whether a further escalation remains on the table. The ambiguity contributed to a volatile overnight session in futures markets before stocks stabilized on Tuesday morning.

The European Commission responded with unusual sharpness, stating in an official release that it was seeking "full clarity" on the administration's intentions and that the current trade environment was "not conducive to delivering fair, balanced, and mutually beneficial transatlantic trade." EU officials signaled they are prepared to activate their own countermeasures if negotiations do not progress, raising the specter of a broader trade confrontation between two of the world's largest economic blocs.

Wall Street registered the shock on Monday, with the S&P 500 declining more than 1%, the Dow Jones Industrial Average falling 1.66%, and the Nasdaq Composite shedding 1.13%. Consumer discretionary stocks, industrials, and companies with deep overseas revenue exposure bore the brunt of the selling, while gold futures surged past $5,192 per ounce as investors sought traditional safe-haven assets. Bitcoin, by contrast, extended its February decline, falling to approximately $63,000 as the cryptocurrency again tracked risk assets rather than serving as a hedge.

Economists offered divided assessments of the tariff's ultimate economic impact. Angelo Kourkafas of Edward Jones argued that a 15% global duty would not pose a severe threat to the economy, pointing to resilient domestic demand and strong corporate balance sheets. Others warned that prolonged trade uncertainty is the primary risk, with Starwood Capital's Barry Sternlicht stating publicly that "uncertainty is bad for business" and cautioning that companies are likely to delay investment decisions until the policy landscape becomes clearer.

On Tuesday, equities staged a partial recovery as investors digested the customs notice confirming a 10% rate rather than 15%, and as the Meta-AMD deal helped restore confidence in technology spending. The Dow added 421 points, or about 0.9%, while the S&P 500 rose 0.4%. However, analysts cautioned that the tariff situation remains fluid, and that any escalation toward 15% or retaliatory action from Brussels could quickly reverse the rebound.