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Japan
Santoku Corporation
Rare-earth alloy and metal producer, not a magnet maker: pioneer of the strip-cast NdFeB alloy process (introduced 1991) and a supplier of NdFeB and SmCo alloys, powders, and recycled rare-earth metal to magnet manufacturers.
At a glance
- Founded
- 1949 — Predecessor operations date to 1937. Wholly owned by Hitachi Metals (renamed Proterial in 2023 under a Bain Capital-led consortium) since November 2017.
- Headquarters
- Kobe, Japan, with plants in Kobe, Miki, Akashi, and Tsuruga
- Ownership
- Wholly owned subsidiary of Proterial, Ltd. (formerly Hitachi Metals), under a Bain Capital-led consortium since 2023. The company's own materials refer to a subsidiary relationship with a newly separated entity, "Proterial Magnetics, Ltd.," effective April 1, 2026; this could not be independently confirmed from a third-party source.
- Revenue
- Not publicly disclosed. This company does not publish revenue and no named third party has published an estimate of it.
Private subsidiary; no revenue breakout found.
Capacity
Each date below links to the document the figure came from. A capacity figure with no source is not on this page.
| What | Figure | Status | As of |
|---|---|---|---|
| NdFeB strip-cast alloy | Not disclosed | Operating | 2026 |
| SmCo alloy and powder | Not disclosed | Operating | 2026 |
| Rare-earth metal recycling | Not disclosed | Operating | 2026 |
Narrative
Santoku Corporation is a Japanese rare-earth alloy and metal producer headquartered in Kobe, with additional plants in Miki, Akashi, and Tsuruga. It has been a wholly owned subsidiary of Hitachi Metals, renamed Proterial in 2023 following its acquisition by a Bain Capital-led consortium, since November 2017. Santoku does not make finished magnets; it supplies strip-cast NdFeB alloy, SmCo alloy and powder, and recycled rare-earth metal to magnet manufacturers, and is credited with introducing the strip-cast NdFeB alloy process in 1991, a role comparable to that of Less Common Metals in the European supply chain. The company's own materials describe a subsidiary relationship with a newly separated entity called "Proterial Magnetics, Ltd.," said to take effect April 1, 2026; this could not be independently confirmed from a source other than the company itself. No public production-capacity figures in tons per year were located for any of Santoku's three main product lines, each of which is disclosed only qualitatively as an active business line.
Where public sources disagree
- The claimed April 2026 change to a "Proterial Magnetics, Ltd." subsidiary structure is sourced only to the company's own materials and has not been independently confirmed.
- No public capacity figures (tons per year or equivalent) were found for NdFeB strip-cast alloy, SmCo alloy/powder, or rare-earth metal recycling.
- A reported government grant to support refining-equipment investment could not be traced to any independent public source and is not included in this profile.
Sources
- Company website — Santoku Corporation (2026-09)
How this page is sourced
Everything here comes from public sources — company filings, annual reports, exchange announcements, government releases and trade press. Every figure is linked to the document it came from and carries the date that document was published, because a capacity number without a date is not a fact, it is a rumor with a decimal point.
What is deliberately absent: material nonpublic information. I have spent more than two decades in this industry and a good deal of what I know about these companies I learned under NDA. Those obligations do not expire and they do not bend for a website. Nothing I have been told in confidence appears here in any form, and nothing on this page — or missing from it — should be read as a signal about what I know privately. I hold NDAs absolutely. It is the reason clients tell me things.
Judgment is the other thing left out on purpose. This page reports what has been published and who published it. Whether a target is credible, whether a ramp will hold, whether a capacity figure survives contact with the plant behind it — that is the work I do for clients, and it does not belong in a free reference page.
Where public sources disagree, I say so rather than picking a winner. Where a figure has not been published, the field says so rather than carrying an estimate. An empty field is information too.
Public filings tell you what a company has said. Whether it holds up is a different question, and the one I get hired to answer.
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