Which Factory Made This Lot? What the Unimicron Investigation Means for PCB Buyers

On August 19 we told buyers to verify a supplier's factory rather than just its paperwork. Ten days later, prosecutors raided a supplier that has factories in Taiwan and China, which raises an important question: when your supplier has factories on both sides of the Strait, how do you confirm where your components are being made?

On August 28, prosecutors and investigators from the Taoyuan District Prosecutors' Office searched the headquarters of Unimicron Technology in Guishan and a plant in Zhongli. Fourteen executives and employees were questioned as suspects, four more as witnesses. By the following afternoon the office had published the outcome: a general manager of the printed circuit board division, surnamed Wang, released on NT$15 million bail; a deputy general manager, surnamed Wu, on NT$12 million; three others on amounts between NT$300,000 and NT$5 million; nine released without bail.

The allegation is that Unimicron shipped printed circuit boards made at its plants in China back to Taiwan and relabeled them as Taiwanese products. Prosecutors cited Articles 210, 216 and 255 of the Criminal Code, which cover forging private documents, using them, and falsely marking the origin of goods. Unimicron's spokesperson said the company is cooperating fully and, in a filing to the stock exchange, that it does not expect a material effect on operations. Shares fell about 10 percent when trading resumed. No charges have been filed. The investigation is open, prosecutors have said they intend to widen it, and everyone questioned is entitled to the presumption of innocence.

This is the second origin case in Taiwanese electronics in less than a month. On August 18, the Ciaotou office detained the head of Hang Jian Technology over training drones delivered to the 8th Army Corps with, prosecutors allege, Chinese flight controllers and Chinese-packaged chips under falsified certificates of origin. We covered that case in detail, including the procurement record behind it. The two cases sit at opposite ends of the industry.

What the August 19 checklist could not have caught

Hang Jian is a small integrator with a NT$2.95 million army contract. Its website claims in-house manufacturing across the aircraft; its capability page lists CNC machines, a laser cutter and composite tooling, and no board assembly of any kind. Our advice on August 19 was built on that gap. Ask to see the surface-mount line. Ask which fab produces the boards. A firm that has the capability can show it; a firm that does not cannot produce it on request.

Unimicron can produce it on request. It is one of the largest PCB and IC substrate makers in the world, a supplier to Nvidia, Intel, Google and Amazon, and it manufactures in Taiwan, China, Germany and Japan. Its advanced substrate capacity is at Yangmei in Taoyuan. Its standard PCB, HDI and flexible board production is, by its own public account, largely in China. The boards in this case appear to be conventional PCBs rather than the ABF substrates that go into AI accelerators, though prosecutors have not said so directly and buyers should not assume it.

A buyer who audited Unimicron's Taoyuan lines would have seen real lines, real equipment, real output. That audit would have passed. The allegation is not that the company lacked the ability to make boards in Taiwan. It is that, for some lots, it did not, and said it had.

That is the distinction this case adds. Capability verification establishes that a supplier can build a part where it says it does. It says nothing about where a particular lot was built when the supplier can build it in two or more countries. For Taiwanese electronics, that describes a great many companies. Taiwan's own customs administration and a risk consultant writing in the Kaohsiung Times make the same point about the Southeast Asian plants Taiwanese firms have opened since 2018: upstream materials, molds, semi-finished goods and key components in many of them still come from China, and a product does not acquire Vietnamese or Thai origin because it left from a Vietnamese or Thai port.

For a drone buyer this matters at the PCB assembly layer specifically. Every flight controller, ESC, BMS and datalink is a board. A Taiwanese assembler that buys bare boards from a supplier with dual-country production, and does not ask which plant produced them, has an origin gap it cannot see and cannot disclose to you.

What "origin" means, in one screen

The legal question underneath both cases is substantial transformation. Both Taiwan and the United States use the concept but they apply it differently.

Taiwan's rules of origin treat a good as Taiwanese if processing here changed the first six digits of its tariff classification, or completed an important manufacturing step, or added more than 35 percent of value. The US test, as CBP applies it, asks whether processing produced a new article with a different name, character or use, and where the essential character was formed. Under neither test does packaging, testing, relabeling or simple assembly qualify.

This has two consequences. First, a Taiwan customs determination does not bind US Customs, which makes its own finding on the facts of each entry. Second, your contract can be stricter than either: a buyer is free to require that a board be fabricated, not merely finished, in a named country, and to require evidence of it. The FCC's Covered List, which we wrote about last week, turns on where a product was made rather than whether it is Chinese-owned. An origin claim is the input to every one of these determinations. If the claim is wrong, the determination is wrong.

Our compliance guides cover the US and EU rules in more detail.

Who pays when the label is wrong

The Unimicron case is a Taiwanese prosecution under Taiwanese law. The financial exposure it illustrates is mostly not in Taiwan.

Since August 2025, US Customs and Border Protection has applied an additional 40 percent duty to goods it finds were transshipped through a third country to evade tariffs. The agency has no authority to waive it. It is assessed against the importer of record, which for a Taiwanese component means the American customer, not the Taiwanese supplier. In July, the Department of Justice announced a US$5.15 million settlement with Everlight Electronics, a listed Taiwanese LED maker, and its Texas subsidiary over undeclared duties on Chinese-origin LEDs. The DOJ Trade Fraud Task Force behind that settlement has recovered more than US$1 billion since it was established a year ago. The White House has named Taiwan among the jurisdictions it considers at elevated risk for transshipment.

Taipei has responded on its own side. Prosecutors published names and bail amounts within 24 hours of raiding one of the country's most important listed technology companies. In April, the Ministry of Economic Affairs proposed cash rewards of up to 20 percent of collected fines for reporting false origin labeling. The Hang Jian case is the first time the National Security Act has been used in a drone procurement. Whatever the outcome of either prosecution, the enforcement environment for "Made in Taiwan" is now real on both sides of the Pacific.

For European buyers the exposure runs the way we described on August 19. Under SAFE and EDIP, a component's declared origin feeds the European-content calculation of the OEM that integrated it. A Taiwanese board that turns out to be Chinese does not just lose its Taiwanese status. It moves value from the 35 percent third-country bucket into a category that may not be eligible at all, and the compliance problem belongs to the party claiming the threshold.

The standard that survives this case

Last week we profiled E-CURRENT, a Taiwanese battery pack maker, because it did something unusual: it walked through its bill of materials layer by layer, named its suppliers, and volunteered the two inputs it has not managed to source outside China. That disclosure was at the level of the material. The Unimicron case says the same disclosure is needed at the level of the lot.

For any supplier with production in more than one country, and for any assembler buying from such a supplier, that means four things a buyer can write into a purchase order:

Plant of origin on the certificate of conformance, per shipment. Not "Taiwan." The site. A supplier that runs a Taoyuan line and a Kunshan line knows which one produced a lot, because its own manufacturing system recorded it. Ask for the record, not the summary.

Lot-level traceability to the work order. The Kaohsiung Times consultant described the evidence chain customs authorities actually test: the flow of goods, money, information and process must agree. Bills of materials, incoming material records, work orders, equipment logs, labor hours, invoices and transport records for the lot should tell one story. A supplier that can produce them for an audit can produce them for a customer.

Origin declared by the party that made the board, not the party that sold it. An assembler's certificate of origin attests to assembly. If fabrication origin matters to your program, the declaration has to come from the fabricator, and the assembler should be contractually obliged to pass it through unaltered.

A right of audit that extends to the plant named. Capability verification is still the foundation. The addition is that the right to inspect follows the declaration: if a lot is declared from Taoyuan, you may see Taoyuan's records for that lot.

None of this is exotic. It is what a competent quality department already does for a critical part, applied to a field that has until now been treated as a formality. The Hang Jian case showed that the field can be falsified by a small company with no factory. The Unimicron case shows, if the allegations are borne out, that it can be falsified by a large company with two.

What to watch

Whether the boards were exported. Prosecutors have not said where the relabeled boards went. If they stayed in Taiwan the matter is a domestic prosecution. If they were exported, particularly to the United States, the case potentially becomes a customs matter for the importers.

Whether a customer opens its own review. The commercial consequence for a supplier at Unimicron's level is not the fine. It is a major customer initiating a special audit, demanding evidence for past shipments, or moving qualification of a next-generation part to another vendor. None of that is likely to be announced publicly.

Whether Taiwan's military changes acceptance inspection. KMT legislator Ma Wen-chun has asked the Ministry of National Defense to review drones already procured and to check parts rather than papers. A ministry commitment to pre-delivery component verification would be the first structural change to come out of either case.

Indictment decisions. Both cases are at the investigation stage. Prosecutors sought detention in one and bail in the other. The charging decisions, and what the charges specify about which products and which markets, will reveal much more than we know now.

Unimicron Technology Corp. and the individuals questioned have not been charged with any offense. The investigation is ongoing. Details of the investigation are drawn from public statements by the Taoyuan District Prosecutors' Office as reported by the outlets listed above; the company's position is drawn from its spokesperson's statement and its exchange filing as reported. The characterization of the affected products as conventional PCBs rather than IC substrates is Tom's Hardware's reading, citing Nikkei Asia, and has not been confirmed by prosecutors.