Sub-layers
Each sub-layer carries a substitutability weight between 0 and 1: how hard it would be to replace the countries that supply it. A high weight sitting on a concentrated share is what makes a chokepoint.
| Sub-layer | Substitutability | Grade |
|---|---|---|
| HBMHigh-bandwidth memory stacked beside the accelerator. SK hynix held 56.4% of HBM revenue in Q1 2026, down from 63.2% across 2025 as Micron and Samsung qualified parts — still the tightest memory position, but visibly loosening. | 0.95 | B |
| Conventional DRAMStandard DRAM. Three firms take more than 90% of revenue; Samsung led Q1 2026 at 38%, SK hynix 29.1%. | 0.90 | B |
| NANDNAND flash. Less concentrated than DRAM, with a meaningful Japanese and Chinese presence. SK hynix was second at 18.5% in Q1 2026. | 0.75 | C |
| Enterprise SSDController-plus-NAND modules sold into servers. More contestable than the underlying NAND. | 0.55 | C |
| HDDNearline hard drives, still the cost floor for bulk training-data storage. A two-country duopoly. | 0.60 | C |
| ControllersStorage controller silicon. Taiwanese fabless vendors hold much of the merchant market. | 0.40 | C |
Physical: where the assets sit
Ranked by share of global memory fab capacity (%) · 7 countries with a non-zero value
| # | Country | Share of global memory fab capacity (%) |
|---|---|---|
| 1 | South Korea | 55 % C |
| 2 | China | 15 % C |
| 3 | United States | 12 % C |
| 4 | Japan | 12 % C |
| 5 | Taiwan | 4 % C |
| 6 | Singapore | 2 % C |
| 7 | India | 0.2 % C |
Top 7 of 7. The full ranking is in the interactive atlas.
Ownership: who books the revenue
Ranked by domiciled supplier revenue ($bn) · 5 countries with a non-zero value
| # | Country | Domiciled supplier revenue ($bn) |
|---|---|---|
| 1 | South Korea | 315 $bn A |
| 2 | United States | 63 $bn B |
| 3 | Japan | 18 $bn B |
| 4 | China | 9 $bn C |
| 5 | Taiwan | 7 $bn B |
Top 5 of 5. The full ranking is in the interactive atlas.
Control: who could stop you
Ranked by chokepoint score, aggregate (leader = 100) · 5 countries with a non-zero value
| # | Country | Chokepoint score, aggregate (leader = 100) |
|---|---|---|
| 1 | South Korea | 100 C |
| 2 | United States | 70.7 C |
| 3 | Japan | 15.6 C |
| 4 | China | 8.9 C |
| 5 | Taiwan | 7.9 C |
Top 5 of 5. The full ranking is in the interactive atlas.
Largest suppliers
15 suppliers sit in this tier; the 15 largest by revenue are below. Revenue is the group or segment figure closest to this tier's perimeter, which is why the ownership basis is graded no better than B even where every line is filed.
| Company | Domicile | Revenue |
|---|---|---|
| Samsung Electronics — DRAM, HBM, NANDLed DRAM at 38% share in Q1 2026 and is recovering HBM position via HBM3e/HBM4. | KR | $240bn |
| SK hynix — DRAM, HBM, NAND56.4% of HBM revenue in Q1 2026, from 63.2% across 2025 — still the tightest single position in memory, but no longer widening. | KR | $70bn |
| Micron — DRAM, HBM, NANDOnly US-domiciled DRAM maker; expanding HBM aggressively. | US | $37bn |
| Kioxia — NAND, enterprise SSD | JP | $13bn |
| Seagate — Nearline HDDBulk training-data storage economics still rest on HDD. | US | $9bn |
| Western Digital — Nearline HDD | US | $9bn |
| SanDisk — NAND, SSD | US | $8bn |
| Solidigm — Enterprise SSDSK hynix subsidiary; classified by parent domicile. | KR | $5bn |
| YMTC — NANDExport-controlled; capacity growth is hard to observe. | CN | $5bn |
| Toshiba Electronic Devices — HDDThird HDD supplier. | JP | $5bn |
| CXMT — DRAMFastest-growing unobserved variable in memory. | CN | $4bn |
| Phison — Storage controllers | TW | $2bn |
| Nanya Technology — DRAM | TW | $2bn |
| Winbond — Specialty memory | TW | $2bn |
| Silicon Motion — Storage controllers | TW | $1bn |