AsianFin — China’s Commerce Ministry said late Wednesday that U.S. optical fiber exporters have been circumventing existing anti-dumping measures, and announced new duties will take effect starting Thursday.

The ministry (MOFCOM) ruled that U.S. manufacturers altered trade patterns to ship certain cut-off shifted single-mode optical fiber into China without commercial justification, undermining the effectiveness of earlier anti-dumping orders.

Following the investigation, the Customs Tariff Commission of the State Council decided to impose anti-dumping duties on the products beginning Thursday, with the measures set to run through April 21, 2028, according to the official statement.

A MOFCOM spokesperson noted this marks China’s first anti-circumvention investigation, which was launched after a domestic company filed an application.