On March 12, 2026, the United States announced a series of new Section 301 investigations targeting the trading practices of China, Mexico, the European Union, and more than a dozen other economies, including Singapore, Switzerland, India, and Norway [1]. Section 301 of the Trade Act of 1974 empowers the Office of the United States Trade Representative (USTR) to investigate whether the acts, policies, or practices of foreign countries are unreasonable or discriminatory and burden or restrict U.S. commerce [1]. Jamieson Greer of the USTR stated that these probes will examine whether these practices burden U.S. commerce and what actions, if any, should be taken [1].
Historically, Section 301 investigations have led to the imposition of tariffs, as seen during the first Trump administration, which conducted six such probes, including two into China and the EU that resulted in tariffs [1]. The Biden administration also utilized Section 301 for trade investigations [1]. If the current probes find against the targeted economies, the USTR has the authority to impose new tariffs or import restrictions, potentially as soon as the summer of 2026 [1]. The agency may also withdraw or suspend trade agreement concessions or negotiate deals if the foreign economies agree to cease the conduct or compensate the U.S. [1]. Retaliatory actions are intended to match the value of the burden imposed on U.S. commerce [1].
These investigations follow a U.S. Supreme Court ruling that declared the Trump administration's "reciprocal" tariffs, imposed in April 2025 under the International Emergency Economic Powers Act 1977, unlawful [1]. In response, the White House imposed a temporary 10% "universal" tariff on all imported goods using Section 122 of the Trade Act of 1974, with the possibility of increasing the levy to 15% [1]. However, these tariffs are temporary, and Trump has expressed a desire to restore tariffs that were previously disallowed [1].
The latest Section 301 probes focus on "structural excess capacity and production in manufacturing sectors," with claims that rival economies are "dumping" excess production onto U.S. markets, threatening domestic manufacturers [1]. The USTR noted that these practices pose a "serious challenge" to Trump's reindustrialization efforts and hinder efforts to re-shore critical supply chains and create good-paying jobs for American workers [1]. The U.S. attributes persistent trade deficits and challenges to domestic manufacturing to these dynamics [1].
CONCLUSION
The U.S. has launched broad Section 301 investigations into the trade practices of 16 economies, with the potential for new tariffs or import restrictions as soon as summer 2026. These actions follow the Supreme Court's rejection of previous tariffs and reflect ongoing efforts to address perceived unfair trade practices and support domestic manufacturing. The market impact is likely to be significant, given the scope and potential for retaliatory measures.