In August 2026, the U.S. quietly placed Vietnam and Thailand on a “Tier 2” watch list in its latest Transshipment Report. The stakes? A non-negotiable 40% penalty tariff on goods suspected of merely bypassing China tariffs.For years, the “China + 1” migration felt like the perfect supply chain escape route. But the reality on the ground tells a different story. Raw materials and components are still pouring out of Southern China, crossing borders via truck, to be quickly assembled in ASEAN facilities.

U.S. Customs is intensifying scrutiny on origin documentation for Southeast Asian imports.. Source：Facebook

Now, U.S. Customs and Border Protection (CBP) is demanding airtight traceability to prove “substantial transformation,” not just simple relabeling. Combine this with the recent October news that the U.S. is actively overhauling the $800 De Minimis duty-free exemption, and the administrative margin for error has effectively dropped to zero.The modern supply chain war isn’t just fought on container ships; it’s fought on documentation. An ocean freight delay might hurt quarterly margins, but a failed customs audit can cripple a business.