In March 2026, the United States Trade Representative (USTR) initiated two significant investigations under Section 301(b) of the Trade Act of 1974 that directly affect Thailand. The first investigation examines overproduction in manufacturing sectors caused by government support or policies that distort normal market conditions across 16 economies, including Thailand. The second investigation, launched the following day, targets 60 economies, also including Thailand, for alleged failures to impose and effectively enforce prohibitions on the importation of goods produced with forced labor.

Taken together, these investigations represent a significant escalation in US trade enforcement and create substantial risk for Thai exporters, manufacturers, and businesses with supply chain connections to the United States. The investigations are moving on an accelerated timeline, with the USTR indicating that potential trade measures, including tariffs, could be imposed as early as July 2026.

This article provides an overview of the investigations, highlights their specific implications for Thailand, and outlines practical considerations for affected businesses.

Section 301 as a Trade Enforcement Tool

Section 301 of the Trade Act of 1974 gives the USTR authority to investigate foreign acts, policies, or practices that are considered unreasonable or discriminatory and that burden or restrict US commerce. If the USTR concludes that such practices exist, the statute allows a wide range of remedial measures, including the imposition of tariffs, nontariff trade restrictions, and negotiated agreements with foreign governments. Unlike other trade authorities, Section 301 does not set limits on the level of tariffs or the duration of measures, giving the USTR considerable flexibility to address perceived trade imbalances or unfair practices.

Historically, Section 301 investigations take up to a year to complete. In this instance, however, the USTR has indicated that the investigations will proceed on a much faster timetable, with an unofficial target of concluding by July 2026. The compressed schedule increases the importance of early engagement by affected businesses and underscores the need for careful planning and strategic responses.

Investigation 1: Structural Excess Capacity in Manufacturing

The first investigation targets 16 economies that the USTR has identified as exhibiting structural excess capacity in certain manufacturing sectors. In addition to Thailand, the investigation includes Bangladesh, Cambodia, China, the European Union, India, Indonesia, Japan, Malaysia, Mexico, Norway, Singapore, South Korea, Switzerland, Taiwan, and Vietnam.

The USTR distinguishes structural overproduction from normal cyclical fluctuations in supply, describing it as production that exceeds market demand and is sustained by government interventions or policies that distort competitive conditions. The USTR contends that such conditions can result in overproduction, persistent trade surpluses, and underutilized capacity, which may displace US production or deter investment in US manufacturing.

The official notice, which appeared in the Federal Register, lists a wide array of sectors that may be affected, including aluminum, automobiles and auto parts, batteries, cement, chemicals, electronics, energy products, glass, machine tools, machinery, nonferrous metals, paper, plastics, processed food and beverages, robotics, satellites, semiconductors, ships, solar modules, steel, and transportation equipment. The breadth of these sectors suggests that the investigation may affect a wide range of Thai exporters and supply chains.

The investigation also identifies specific government actions that may contribute to overproduction, including export-promotion subsidies, noncommercial activities by state-owned or state-controlled enterprises, market access restrictions, wage suppression, weak environmental or labor protections, subsidized lending, and currency or financial interventions. The USTR will evaluate whether these practices exist and whether they unfairly burden or restrict US commerce.

Investigation 2: Forced-Labor Enforcement

The second investigation examines whether 60 economies, including Thailand, have failed to impose and effectively enforce bans on imports of goods produced with forced labor. US law defines forced labor as work or service exacted under threat of penalty where the worker has not volunteered freely.

The USTR has emphasized that the lower cost of goods produced with forced labor can create unfair competition that harms US producers and workers. The investigation will consider whether foreign governments have enacted effective legal frameworks to prevent the importation of such goods and whether those frameworks are actively enforced.

For Thailand, this investigation is especially important given the historical focus on labor conditions in certain sectors, including seafood, garments, agriculture, and some manufacturing supply chains. The inquiry is likely to increase expectations for supply chain transparency, due diligence, and traceability for companies exporting to the United States.

A key concern is whether Thailand imports goods from Xinjiang, China, where there are documented reports of forced labor involving the Uyghur population. The US government has taken an increasingly aggressive stance on imports linked to Xinjiang, including through the Uyghur Forced Labor Prevention Act, which creates a rebuttable presumption that goods produced in whole or in part in the Xinjiang Uyghur Autonomous Region are made with forced labor. Thai exporters whose supply chains include components or materials sourced from Xinjiang may face heightened scrutiny and potential restrictions when exporting to the United States—particularly when their supply chains contain direct or indirect links to Xinjiang-sourced materials, including cotton, polysilicon, tomatoes, and other products commonly associated with forced labor concerns in that region.

Specific Implications for Thailand

Thailand’s inclusion in both investigations increases the potential exposure for Thai businesses. The USTR’s Federal Register notice highlights Thailand’s global trade surplus in sectors such as automobiles and auto parts, machinery, and rubber, and notes that Thailand’s bilateral trade surplus with the United States reached approximately USD 51 billion in 2025, up from USD 35 billion in 2024.

In addition, the USTR cited evidence suggesting that Thailand’s manufacturing sector has significant excess capacity, with capacity utilization below 60 percent for two consecutive years and uneven recovery across industries following the pandemic. These findings indicate that Thailand may be subject to heightened scrutiny during the investigation.

While the forced labor investigation focuses on supply chain risks rather than specific determinations against Thailand, it is likely to increase compliance expectations and could lead to enforcement measures affecting Thai exports. In response, Thailand’s Ministry of Commerce has established a special task force, led by the ministry’s permanent secretary, to manage the potential impact of US tariffs and coordinate the country’s response. Thai authorities have confirmed ongoing engagement with US counterparts, including preparation of submissions in connection with the investigations. Nevertheless, the combination of broad scope and accelerated timelines presents a substantial challenge for both government and private-sector stakeholders.

Key Deadlines

The deadline for submission of written comments, requests to appear at hearings, and summaries of testimony for both investigations is April 15, 2026, at 11:59 p.m. Eastern Daylight Time. Public hearings for the structural excess capacity investigation are scheduled to take place from May 5 to May 8, 2026, with post-hearing rebuttal comments due seven days after the final hearing day. Public hearings for the forced labor investigation are scheduled to begin on April 28, 2026, and may continue through May 1, 2026, as necessary.

The USTR has indicated an unofficial target of completing the investigations and preparing potential tariff measures by approximately July 2026, making timely engagement essential for affected businesses.

Potential Outcomes

If the USTR finds actionable practices under Section 301, remedial measures could include increased tariffs, nontariff trade restrictions, or negotiated agreements with foreign governments to address the practices identified. Given the number of sectors under review, any tariffs or restrictions could be broad in scope and impact.

The USTR has also signaled that additional Section 301 investigations may follow, potentially addressing issues such as pharmaceutical pricing, digital services taxes, ocean pollution, and trade practices related to seafood and agricultural products. Many of these areas are directly relevant to Thailand’s export profile, indicating that the current investigations may be part of a wider enforcement strategy.

Practical Considerations for Businesses

Companies exporting to the United States or participating in US-bound supply chains should assess their exposure to potential Section 301 tariffs. This includes reviewing product classifications, identifying affected sectors, and evaluating both direct and indirect exposure through third-country suppliers.

Participation in the USTR’s public comment process offers a formal mechanism to present evidence and arguments regarding the existence of alleged practices, potential economic impacts, and consequences for US consumers and downstream industries. Coordinated submissions by industry associations can help ensure that sector-wide perspectives are effectively conveyed.

In light of the forced labor investigation, companies should review and strengthen supply chain compliance programs and due diligence processes. Demonstrable compliance with international labor standards and the ability to trace supply chains will be critical in managing enforcement risk.

Businesses should also evaluate strategies to mitigate the impact of potential tariffs, such as reviewing tariff classifications, confirming country-of-origin determinations, and exploring supply chain diversification where feasible. Given the accelerated timeline and possibility of follow-on investigations, business should closely monitor USTR announcements and Federal Register notices for potential changes in US trade policy.

The USTR’s Section 301 investigations are a major development in US trade enforcement with direct implications for Thailand. The wide scope of sectors under review, Thailand’s inclusion in both investigations, and the compressed timeline make early preparation and strategic engagement essential.