U.S. Issues Final Anti-Dumping Ruling on Chinese MDI: Dumping Margins Reduced from Over 500% to 85%+

On April 8, 2026, the U.S. Department of Commerce announced its final affirmative determination in the anti-dumping investigation on imports of methylene diphenyl diisocyanate (MDI) from China.

The final dumping margins are set at 85.11% for Covestro Polymers (China) Co., Ltd., Wanhua Chemical Group Co., Ltd., and its exporter Shandong Mingko Co., Ltd., while other Chinese producers/exporters are assigned a rate of 159.04%.

The products under investigation are primarily classified under U.S. Harmonized Tariff Schedule (HTSUS) codes 2929.10.8010 and 3909.31.0000.

These final rates represent a significant reduction compared to the preliminary determination issued in early September 2025, when dumping margins ranged from 376.12% to 511.75%.

The United States has long been the largest export market for China’s polymeric MDI. However, affected by the anti-dumping investigation, China’s exports to the U.S. dropped sharply by 82.6% year-on-year during January–October 2025.

The final ruling removes a degree of uncertainty, giving companies some breathing room to reassess and plan their export strategies to the U.S. market.

That said, from an objective standpoint, the 85.11% dumping margin, combined with existing base tariffs, still results in a relatively high overall tariff burden for Chinese MDI in the U.S. market. The ruling effectively lowers “prohibitively high tariffs” to “high tariffs,” meaning Chinese products continue to face a tariff premium compared to competitors from other countries, and profit margins remain under pressure.