⚠ Two Customers, Two Countries, One ProductHigh threat

SK hynix (SKHY) — threat to the moat

The revenue concentration is disclosed and high; the profit concentration is undisclosed and higher, because almost all of the incremental margin comes from one product sold into one buyer's roadmap.

SK hynix's revenue concentration is high. Its profit concentration is considerably higher, and it is not disclosed.

Three concentrations, stackedBy customer23.9% of 2025 revenue in one relationshipBy productDRAM 77.3% of Q1 2026 salesBy profitAlmost all incremental margin is HBMBy geographyThe United States and ChinaOnly the first of these appears in a concentration table.
The revenue table understates it, because margin is far less diversified than sales.

The filing gives the visible layer: a largest customer at 23.9% of 2025 revenue, top-two customers at 14.8% and 12.4% in the first quarter of 2026, located in the United States and China1. That alone would be a meaningful dependence.

The layer beneath it is where the risk actually sits. Nearly all of the incremental profit comes from high-bandwidth memory, and the large majority of high-bandwidth memory goes into AI accelerators, and one company makes most of those accelerators. The revenue table understates the exposure because it measures revenue rather than margin, and the margin is far less diversified than the sales are.

Geography compounds it. A Korean supplier selling primarily into the United States and China sits inside a technology dispute between its two largest markets, subject to export rules it does not influence and industrial policy designed to replace it in one of them.

The mitigation is that these buyers are among the world's most cash-generative companies, and that one of them has committed about US$279 billion to its own suppliers, primarily for memory2. Neither addresses the case where they slow simultaneously, which is the case that matters, because they are all spending on one shared conviction.

The number to watch is the largest customer's capital-expenditure guidance. It is a more reliable forecast of SK hynix's revenue than SK hynix's own.

The number that tests this threat
Reported
Two largest customers, Q1 2026
14.8% and 12.4% — largest 23.9% for 2025

The visible concentration, in customers the filing places in the United States and China and declines to name. The invisible concentration is worse: DRAM was 77.3% of first-quarter sales and essentially all the incremental profit is high-bandwidth memory sold into one buyer's roadmap. Watch that buyer's capital-expenditure guidance.

Source: SK hynix Form 424B4 prospectus (10 July 2026) ↗
References
  1. ReportedA largest customer at 23.9% of 2025 revenue and top-two customers at 14.8% and 12.4% in the first quarter of 2026, located in the United States and China.
    SK hynix Inc., Form 424B4 prospectus — risk factors and the offering (SEC, CIK 2120882). 'A substantial portion of our sales is attributable to a limited number of customers located in the United States and China. Our two largest customers represented 14.8% and 12.4%, respectively, of our total revenue in the first quarter of 2026 and our largest customer represented 23.9% of our total revenue in 2025.' DRAM products were 77.3% of total sales in Q1 2026 and 77.1% in 2025; NAND flash 22.0% and 21.3%. NAND mass production is transitioning from 176-layer technology to 238- and 321-layer technologies. The offering was 177,900,000 ADSs at US$149.00 each, representing 17,790,000 common shares against 712,702,365 outstanding, each ADS one-tenth of a share; Baillie Gifford Overseas, funds managed by Coatue Management and Situational Awareness Partners indicated a non-binding interest of up to US$7 billion. — FY2025 and Q1 2026 · publ. 2026-07-10 · source ↗
  2. ReportedNVIDIA has committed about US$279bn to its own suppliers, primarily for memory.
    NVIDIA Q2 FY2027 CFO commentary (Form 8-K, exhibit 99.2) — Data Center revenue of $89,023M splits into Hyperscale $48,710M (+102% year on year, +13% sequentially), AI Clouds/Industrial & Enterprise $40,313M (+138%, +25%) and Edge Computing $7,198M (+27%, +13%); shipments of Data Center Hopper products to China during the quarter were less than 1% of Data Center revenue; purchase commitments increased from $119 billion in the prior quarter to $279 billion, primarily related to the procurement of memory; segment revenue was Compute & Networking $88,299M (+114%) and Graphics $7,922M (+46%) — Q2 FY2027 (quarter ended 26 July 2026) · publ. 2026-08-26 · source ↗
Sources
Generated September 23, 2026