Near-line HDD and high-capacity mechanical storage
BOTTLENECKHeadway Technologies supplies most read/write heads for near-line HDDs and a duopoly controls pricing, limiting qualified second sources.
High-capacity spinning disks for warm-tier dataset storage, backup, and archival in AI infrastructure. HAMR and MAMR technologies extend density roadmap as flash costs remain prohibitive at petabyte scale. Western Digital and Seagate duopoly maintains pricing; read/write heads supplied mainly by Headway Technologies.
What the evidence shows
In 2025, Western Digital holds 47% HDD capacity market share, Seagate 42%, Toshiba 11%.
forbes.comBoth major U.S. drive makers told investors in early 2026 their nearline output was sold out for the year.
gillware.comThe top three HDD manufacturers hold 89% combined market share in 2025.
industryresearch.bizWho controls it
Where it sits in the stack
Takes in: Read/write heads, platters, voice-coil actuators, spindle motors, enclosure
Sends on: Lowest-cost byte storage for large model datasets and training corpora
Related nodes
Full scorecard, owner shares, supply edges and the full tracked roster are in the desk letter.
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