Taiwanese chip substrate maker Unimicron is under criminal investigation for allegedly passing off China-made goods as Taiwanese, a hit to its stock and a warning sign for Taiwan's whole export machine.

• Prosecutors searched Unimicron over suspected origin-laundering, and its shares dropped sharply.
• The bigger damage is to trust — the thing that lets Taiwanese firms sell into the US at all.
• Taiwan's exports have swung hard from China to the US, with America now taking about a third of shipments, driven by AI hardware.
• Taiwan runs a huge trade surplus with the US, which makes it an obvious target if Washington starts doubting Taiwanese labels.
• Many Taiwanese circuit board makers still run big plants in China, so the temptation to relabel is built into the supply chain.

Outlook: Expect tighter scrutiny of Taiwanese origin rules and more pressure on firms with China-based production to prove where their goods are really made.