# Who does Western Digital pay? Who are its key suppliers?
Canonical: https://valuechain.wiki/western-digital · Facet: suppliers · Updated: 2026-07-12T08:25:12.574179+00:00 · Source: ValueChain.wiki (cited money-flow graph)

**Citable summary**: Western Digital's confirmed suppliers/cost counterparties include HDD glass substrate (Hoya) plus 2 undisclosed/aggregate relationships. Per the valuechain.wiki graph: 3 cost edges, backed by 3 dated sources, 1 of them primary filings (as of 2026-07-12).

### HDD 유리기판 (호야) (mid)  → /hoya.md
- note: Sources glass substrates for high-capacity/HAMR HDDs from HOYA — the 3.5" glass shift is central to the capacity roadmap, so HOYA capacity is the upstream ramp bottleneck.
- [mentions] Tom's Hardware (EN, news, published 2025-05-15) https://www.tomshardware.com/news/hoya-hdd-22tb-24tb: "Hoya is the largest HDD glass-substrate maker for high-capacity drives."

### 헤드·미디어·부품 (비공개) (low)
- note: Heads, media and mechanical parts.
- [mentions] Blocks & Files (EN, news, published 2025-07-31) https://blocksandfiles.com/2025/07/31/western-digital-q4-2025/: "FY2025 results: heads/media, capacity and R&D cost of nearline-HDD manufacturing (individual supplier shares undisclosed)."
- [confirms] SEC EDGAR (EN, filing, published 2025-04-01) https://www.sec.gov/Archives/edgar/data/0000106040/000010604025000020/a4ex991-pressreleaseq325.htm: "Heads, media and mechanical parts."

### 증설·R&D (비공개) (low)
- note: HDD capacity and R&D.
- [mentions] Blocks & Files (EN, news, published 2025-07-31) https://blocksandfiles.com/2025/07/31/western-digital-q4-2025/: "FY2025 results: heads/media, capacity and R&D cost of nearline-HDD manufacturing (individual supplier shares undisclosed)."
- [confirms] SEC EDGAR (EN, filing, published 2025-04-01) https://www.sec.gov/Archives/edgar/data/0000106040/000010604025000020/a4ex991-pressreleaseq325.htm: "HDD capacity and R&D."

Reverse side: https://valuechain.wiki/western-digital/customers.md · Ripple: https://valuechain.wiki/western-digital/ripple.md

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Full node: https://valuechain.wiki/western-digital.md · JSON: https://valuechain.wiki/western-digital.json