The Next Shoe Drops: New Tariff Investigations Against 16 Countries

Continuing the breakneck pace of new developments in the U.S. government's efforts to impose widespread new tariffs against most international trading partners, on March 11, 2026, the U.S. Trade Representative ("USTR") announced new investigations under Section 301 of the Trade Act of 1974 against 16 countries: China, the European Union, Singapore, Switzerland, Norway, Indonesia, Malaysia, Cambodia, Thailand, Korea, Vietnam, Taiwan, Bangladesh, Mexico, Japan, and India.

The new initiatives come in the wake of the U.S. Supreme Court's invalidation of the Administration's "emergency" tariffs imposed under the International Emergency Economic Powers Act ("IEEPA") in a landmark Feb. 20 ruling (see Lewis Brisbois Alert) and a subsequent U.S. pivot to other trade law authorities to reinstate global tariffs (see Lewis Brisbois Alert).

The new Section 301 investigations are based on "evidence" that these economies "appear to exhibit structural excess capacity and production in various manufacturing sectors, such as through large or persistent trade surpluses or underutilized or unused capacity." The USTR announcement lays out allegations as to each of the 16 countries based on trade data. The sectors encompassed include several that are already subject to significant tariffs under another trade law, such as aluminum, automobiles, and steel, as well as new concerns on batteries, cement, chemicals, electronics, energy goods, glass, machine tools, machinery, non-ferrous metals, paper, plastics, processed food and beverages, robotics, satellites, semiconductors, ships, solar modules, and transportation equipment.

While Section 301 investigations include requirements for public comments and hearings, the USTR announcement makes clear the new proceedings will proceed on an expedited timeline, which appears to coincide with the July 27 expiration date of the time-limited tariffs the U.S. imposed on February 24, just days after the Supreme Court's decision. The compressed schedule is as follows:

• March 17, 2026: the USTR docket opens for submission of written comments and requests to speak at the hearings
• April 15, 2026: the docket closes for written comments, requests to appear at the public hearing, and summaries of testimony
• May 5, 2026: hearings will commence, continuing as necessary until May 8
• Seven days after the last day of hearings, rebuttal comments are due

Section 301 includes very broad language allowing the U.S. to impose tariffs without specified upper limits to retaliate against unfair trade practices that burden U.S. commerce. One key purpose of the law is as a tool to negotiate trade agreements, and many such deals were in process under leverage from the now disallowed IEEPA tariffs. It is possible that new trade agreements could resolve some of the Section 301 investigations, but given the abbreviated timeline for these investigations, affected companies will need to consider contesting the allegations during the comment and hearing process.