Foundry
Contract wafer fabrication and advanced packaging that turn accelerator designs into silicon.
Stack position
Where Foundry sits in the AI stack
L3 · Semiconductor Equipment
Lithography, etch, deposition, inspection, and advanced packaging tools.
L3b · Foundry
Contract wafer fabrication and advanced packaging that turn accelerator designs into silicon.
L4 · Compute
GPUs, AI accelerators, and general-purpose compute silicon for training and inference.
L4 · HBM / Memory
HBM/DRAM bandwidth beside accelerators, plus enterprise NAND/HDD capacity. US-listed tickers or ADRs only.
Icons mark layer roles — not company logos. Position only; not a price chart.
Why this layer matters
A design is not a chip. Between the two sits contract fabrication and the advanced packaging that bonds HBM stacks to logic — which is why accelerator shipment volume has repeatedly been set by packaging capacity rather than by wafer starts or by how many chips anyone wanted to sell.
What is the bottleneck?
Leading-edge capacity is concentrated in very few fabs, and a new one takes years and tens of billions. This is the narrowest point in the entire chain.
A structural observation about supplier concentration and lead times — not a view on any security.
Who sits in this layer?
Company
TSMPrimary business sits hereContract logic fabrication and advanced packaging for merchant and custom accelerators.
Company
GFSPrimary business sits hereContract wafer fabrication at mature and specialty nodes.
Company
UMCPrimary business sits hereContract wafer fabrication at mature and specialty nodes.
Company
AMKRPrimary business sits hereOutsourced semiconductor assembly and test, including advanced packaging.
Company
ASXPrimary business sits hereOutsourced semiconductor assembly, test, and advanced packaging services.
Public 13F filings citing these securities
Research context, not a recommendation. These are facts on file with the SEC; the classification that puts a security in this layer is ours, and the filer made no such claim.
- ARK Investment Managementreported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
- Appaloosa Managementreported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
- Bridgewater Associatesreported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
- Coatue Managementreported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
- Duquesne Family Officereported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
- Tiger Global Managementreported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
- Viking Global Investorsreported a position inTSMForm 13F-HR for the period ending 2026-06-30, filed 2026-08-14 · SEC filing
Rows below are public SEC Form 13F-HR filings, reported by the filing entity for the period shown and filed later — they are never current holdings. Form 13F covers long US equity positions only: it excludes short positions, cash, non-US holdings and most derivatives, and a reported position may have been sold since. Assigning a ticker to a layer is XingAI's classification, not the filer's. Nothing here is a recommendation, and an institution reporting a position is not a reason to take one.
Coverage boundary
Coverage boundary: US-listed tickers or ADRs only (same rule as TSM / ASML). Important suppliers without a US listing are omitted even when they matter to the stack. That is a coverage rule, not a quality ranking.
- Samsung Foundry — Major contract foundry; parent has no US primary listing in this map's scope.
- SMIC — Major foundry; no US primary listing in this map's scope.
Checked 2026-10-09. Not exhaustive.
Same track
Descriptive positioning only. The positioning label says whether a company's business is exposed to a layer, never whether to buy it. Layers with no exposure are not recommendations to add any.