What: The US Supreme Court’s ruling on IEEPA tariffs and the introduction of Section 122 duties have reshaped the tariff landscape, creating new uncertainties and operational challenges for businesses.

Why it is important: The evolving tariff landscape highlights the need for robust scenario planning and supply chain resilience, a trend echoed in leading retail and business media.

The recent US Supreme Court decision striking down the use of the International Emergency Economic Powers Act (IEEPA) for imposing tariffs has fundamentally altered the US trade environment. In response, the administration has enacted a temporary 10% global import duty under Section 122 of the Trade Act of 1974, with the possibility of increasing this to 15%. While this reduces the average US trade-weighted tariff rate from 15% to around 12%, the impact varies significantly by country and sector, with the largest reductions seen for imports from China and Brazil, and more modest changes for the EU and UK. Sectors such as consumer electronics, fashion, and luxury will benefit from notable tariff reductions, while others like biopharma and automotives remain largely unaffected. The ruling also raises questions about the future of bilateral trade deals, the potential for tariff refunds, and the administration’s next steps in deploying other trade instruments. As the trade landscape grows more complex, businesses must refine scenario planning, enhance compliance, and build resilience to manage ongoing volatility and uncertainty in global trade policy.

IADS Notes: The US Supreme Court’s ruling and subsequent policy shifts have intensified trade uncertainty, as detailed in Forbes (March 2025) and BCG (April 2025), which highlight the sweeping impact of tariff changes on operational models and costs. The Robin Report (September 2025) and BCG (January 2026) emphasise the growing importance of scenario planning and supply chain resilience, with businesses investing in analytics and diversified sourcing to navigate volatility. Sector-specific analyses from Inside Retail (April 2025) and Vogue Business (March 2025) show how tariff changes are affecting pricing and consumer behaviour, while Forbes (March 2025) and BCG (July 2025) underscore the need for advanced compliance and strategic adaptation amid a patchwork of exemptions and bilateral agreements. Collectively, these sources confirm that the evolving US trade landscape demands agility and innovation from all businesses engaged in international trade.

What does the US Supreme Court ruling on tariffs mean for your business?