Investigation Nos. 731-TA-1782-1785 were instituted on April 8, 2026, launching preliminary phase antidumping duty investigations on polytetramethylene ether glycol (PTMEG) imports from China, South Korea, Taiwan, and Vietnam. The U.S. International Trade Commission published the notice in the Federal Register on April 13, 2026, setting a preliminary determination deadline of May 26, 2026.

For compliance engineering teams pulling tariff data via API, this investigation directly impacts two HTS subheadings: 3907.29.00 (other polyethers in primary forms) and 2932.11.00 (tetrahydrofuran). Any automated classification or duty calculation system referencing these codes for shipments originating from the four named countries must now account for potential antidumping duty exposure.

Key Dates for System Updates:
• Investigation instituted: April 8, 2026
• Preliminary determination deadline: May 26, 2026
• Commission views due to Commerce: June 2, 2026

The petition was filed by BASF Corporation, headquartered in Florham Park, New Jersey, alleging that PTMEG from these four Asian suppliers is being sold in the United States at less than fair value. PTMEG is a critical intermediate chemical used in manufacturing spandex fibers, thermoplastic polyurethanes, and copolyester elastomers — supply chains that span apparel, automotive, and industrial applications.

Trade compliance systems that cache duty rates or flag country-of-origin risk need to incorporate these investigation numbers immediately. The four separate case numbers — 731-TA-1782 (China), 731-TA-1783 (South Korea), 731-TA-1784 (Taiwan), and 731-TA-1785 (Vietnam) — will each produce independent preliminary injury determinations. A positive preliminary finding from the ITC would trigger Commerce Department dumping margin calculations and eventual duty deposits.

Classification Alert: PTMEG imports may be classified under either HTS 3907.29.00 or 2932.11.00 depending on form and chemical specification. Both subheadings are within scope. Ensure your classification logic flags entries under both codes when origin matches the investigated countries.

The compressed 45-day timeline for preliminary phase investigations means compliance teams have less than six weeks from the April 8 institution date to prepare for potential duty implications. If Commerce extends initiation timelines, these dates could shift — but the ITC has already locked in the May 26 preliminary determination target.

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For engineering teams maintaining landed cost calculators or denied party screening integrations, the downstream effect is clear: any PTMEG shipment from China, South Korea, Taiwan, or Vietnam entering after a positive preliminary determination will require duty deposits at rates to be determined by Commerce. Hardcoding current MFN rates without flagging AD investigation status creates compliance exposure.

The ITC will hold a staff conference on April 29, 2026, where interested parties can present arguments on material injury. Requests to appear must be submitted by noon on April 27, 2026. The Commission's electronic docket (EDIS) at edis.usitc.gov will contain the public record for these investigations as they progress.