Eight parts of an AI data center have no US-listed supplier at all

The last piece we published counted how much of this supply chain is listed anywhere at all, and found the answer sorted itself by distance from the chip: 87% of the rack layer has a stock-market listing, 41% of the building shell does. That question has an obvious follow-up, and the answer to it is not the same shape.

Listed and listed in the United States are different facts. Of the 1,163 companies in this catalog sitting on at least one part, 650 have a primary listing somewhere. Half of those placements are American — 622 of 1,221 — and the rest are spread across Taipei, Tokyo, Shenzhen, Seoul, Frankfurt and Paris. Sorted by venue rather than by layer, the map of this supply chain rearranges itself.

The eight

Take the 163 parts that carry three or more listed suppliers — enough that a single missing name cannot swing the result. On eight of them, not one supplier trades on a US exchange.

Six of the eight fall into two tight clusters, and both of them touch the accelerator.

Underneath the die

The first cluster is the stack the GPU is built on. A wafer becomes a die; the die is mounted on a high-layer package substrate; that substrate is made of a build-up film laminated in layers. Each of those three steps is its own part here, and none has an American listing behind it.

Silicon wafers come from five companies: Shin-Etsu and SUMCO in Tokyo, GlobalWafers on the Taipei Exchange, Siltronic on XETRA, and SK Siltron, which is a subsidiary and has no separate listing. ABF substrates come from ten, spread across Taipei, Seoul, Tokyo and Vienna — Unimicron, Nan Ya PCB, Kinsus, Zhen Ding, Samsung Electro-Mechanics, LG Innotek, Daeduck, Ibiden, AT&S, and Shinko, whose ownership this catalog still records as unknown.

Substrate materials is the narrowest of the three. Five suppliers, all five on the Tokyo Stock Exchange: Ajinomoto, Asahi Kasei, Mitsubishi Gas Chemical, Nittobo and Sumitomo Bakelite. There is no second venue on that row at all.

And around it

The second cluster is the mechanical hardware that holds the accelerator and moves air past it — boards, chassis, rails, fans, heatsinks and vapor chambers. Here the concentration is Taiwanese rather than Japanese, and on three of the four parts it is nearly total.

Every listed supplier of motherboards, CPU trays and switch trays trades in Taipei: ASUS, Gigabyte, MSI, ASRock Rack and MiTAC. So does every listed supplier of chassis, rails and rack enclosures — Chenbro, King Slide, Wistron and Foxconn — and every listed supplier of air-cooled heatsinks and vapor chambers: Auras, AVC, Chaun-Choung, Delta, Foxconn and Jentech. Fans is the one that reaches past Taiwan, and only as far as Tokyo, for Nidec and Sanyo Denki.

This is the part worth sitting with. Servers, racks and integration is the most listed layer in the catalog — 122 of its 140 companies have a listing, 87%, the highest of the eleven. It is also the layer holding four of the eight parts on this page. A layer can be almost entirely public and still be almost entirely unavailable on an American exchange.

What this does not say

Three limits, all of them load-bearing.

A listing is not a factory. This counts where a company’s equity trades, and nothing else. Wafer and substrate makers at this scale run plants on several continents, including American ones, and a Taipei or Tokyo listing says nothing about where any particular fab or lamination line sits. This catalog does not record manufacturing locations at all — hq_country is populated for fewer than one company in ten — so read these rows as a map of listing venues, which is what they are.

Two of the eight are boundary cases. On motherboards, the American names are present in this catalog — Supermicro, Dell and HPE — but the taxonomy places them on rack-scale systems and GPU baseboards & compute trays, one level up from the merchant board part. On sensors, Honeywell and Johnson Controls sit on the building management and controls parent rather than the sensors child. Both rows are true as counted and both would change if the taxonomy drew its boundary a little differently. The other six do not depend on where the line falls.

These placements are leads, not disclosures. 1,847 of the 1,863 part-company placements in this catalog are tagged inferred — they come from the taxonomy seed and carry no citation yet. This piece counts rows and listing venues, both of which are checkable; it does not claim any supplier’s share of any part. The sources and method page explains what each confidence tag means and what it would take to move one.

The mirror image

The reverse case is more common and less interesting. Of the same 163 parts, 32 have every listed supplier in a single country — and 28 of those 32 are American. Pipelines and midstream, equipment rental, MEP contractors, transmission EPC, nuclear PPAs: the parts that are bought locally and built on site, whose supplier lists this catalog assembled largely from American filings and American trade press.

That asymmetry is partly a fact about the industry and partly a fact about this catalog, and we would rather say so than pick one. The eight parts above are the more durable finding, because they survive the coverage question: adding more American companies to a wafer or ABF substrate row is not something this catalog has been unable to do. There are not many to add.