Mitsui Kinzoku mid-term plan briefing highlights the balance between VSP copper foil expansion and ROIC management

Overview

This report summarizes the key points from Mitsui Kinzoku's briefing on progress under its 2025-2027 mid-term plan. Management identified market capitalization as the most important KPI, proposed further advancing ROIC management and dynamic portfolio management, and used the sale of Mitsui Kinzoku Act as an example of strategic trade-offs. The report focuses on two themes: first, expansion and higher-end upgrading of the copper foil business centered on MicroThin and VSP; second, the long-term potential of A-SOLiD all-solid-state battery solid electrolyte as a new business pillar. Goldman Sachs maintains a Buy rating on Mitsui Kinzoku with a 12-month target price of ¥44,100.

Core views

Goldman Sachs' core view is that, as investors begin to view Mitsui Kinzoku as a semiconductor-materials stock tied to AI servers, the next stage of corporate value enhancement depends on whether the company can make timely, flexible, and sufficiently large investment decisions for the VSP copper foil business within a ROIC-oriented operating framework. The company has raised its ROIC and ROE targets and increased the VSP FY3/27 capacity plan, but Goldman Sachs believes the FY3/28 outlook of 900 tons/month remains conservative. Management said it does not rule out options such as converting non-VSP capacity, building capacity in-house, or pursuing M&A, and Goldman Sachs will watch whether the company can quickly capture VSP market growth opportunities and avoid share erosion.

Analysis framework

The report combines an interpretation of the company's mid-term plan, a breakdown of profit targets by business, a comparison of capacity and market demand, an assessment of ROIC and capital-expenditure constraints, and Goldman Sachs' valuation framework. For the VSP business, the focus is on the gap between the company's disclosed capacity targets and the forecast size of the high-grade electrolytic copper foil market; for MicroThin, the focus is on upside risk from demand in AI data centers, storage, high-speed optical transceivers, and flexible printed circuits; for A-SOLiD, the focus is on customer commercialization timing in 2027-2028 and the company's mass-production verification progress.

Methodology notes

• Valuation methodsEV/GCI and CROCI/WACC correlation

  Target price valuation framework

  Goldman Sachs' ¥44,100 target price is based on the correlation between the materials segment's EV/GCI and the FY3/27E CROCI/WACC forecast, using a 0.7x cash return multiple and assigning a 45% premium to the sector average.

• factor_profileGS Factor Profile

  Growth, financial returns, valuation multiples, and composite percentile

  Goldman Sachs' factor profile provides investment context for a single stock by comparing growth, financial returns, valuation multiples, and composite metrics with covered stocks and industry peers.

• Corporate fundamentals & financialsROIC management

  Business portfolio management under capital efficiency constraints

  The company emphasizes ROIC management and dynamic portfolio management, and the report uses this to assess whether it can balance capital efficiency and market share while making large-scale expansions in the copper foil business.

Asset mapping & comparison

Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).

• Mitsui Kinzoku (5706.T)

  Subject of the report and rating target

  Strengths

  It has business pillars such as MicroThin, VSP, metal recycling, catalysts, rare materials, ceramics, and A-SOLiD; ROIC and ROE targets have been raised; VSP and MicroThin benefit from demand for AI servers and high-end electronic materials.

  Weaknesses

  Investors worry that the company may place too much emphasis on ROIC and therefore struggle to make timely large-scale expansion decisions; Goldman Sachs views the FY3/28 VSP capacity outlook as conservative.

  Comparison

  Compared with companies in the coverage universe such as Asahi Kasei, Daicel, Denka, Fujimi, Kuraray, Mitsubishi Gas Chemical, Mitsui Chemicals, Nippon Paint, Nitto Boseki, Resonac, Shin-Etsu Chemical, Tokyo Ohka Kogyo, Toray, Tri Chemical, and Zeon.

  Risks

  Slower AI server demand, yen appreciation, lower zinc and other metal prices, and delayed capacity expansion in high-grade copper foil leading to share loss.

• VSP copper foil business

  Core growth and capex watch point

  Strengths

  The FY3/27 capacity target was raised to 782 tons/month, sales of HVLP4-and-above ultra-high-grade products are expected to grow by about 2.5x YoY, and management does not rule out capacity conversion, greenfield investment, or M&A.

  Weaknesses

  The FY3/28 outlook of 900 tons/month may not be enough to match the expansion of the high-grade electrolytic copper foil market; current market share faces a decline risk.

  Comparison

  Goldman Sachs estimates the CY28 HVLP3-and-above high-grade electrolytic copper foil market at about 5,000 tons/month, or about 6,000 tons/month after yield adjustment, while the company's announced capacity for Sep 2028 is 1,200 tons/month.

  Risks

  Insufficiently agile expansion decisions, overly strict capital discipline, and weaker-than-expected AI-related demand.

• MicroThin business

  Business benefiting from AI data center and high-end electronic materials demand

  Strengths

  Demand is being driven by storage, AI data centers, high-speed optical transceivers, and ultra-fine-line flexible printed circuits; FY3/27 sales forecasts were raised by about 15% versus the previous outlook.

  Weaknesses

  FY3/27 sales growth is expected to slow from +45% YoY in the prior year to +13% YoY.

  Comparison

  The company still prepares for upside demand beyond the 5.6 million square meters/month capacity figure.

  Risks

  Slower demand growth or weaker-than-expected application expansion.

• A-SOLiD solid electrolyte

  New business pillar for all-solid-state batteries

  Strengths

  Aimed at supplying commercialization customers in 2027-2028; supply capacity has been quadrupled; the initial mass-production technical verification facility has broken ground, with verification operations targeted for 2027.

  Weaknesses

  It is still before commercialization and mass-production verification, so the timing and scale of revenue contribution remain uncertain.

  Comparison

  Compared with the mature copper foil business, A-SOLiD is more of a long-term growth option.

  Risks

  Delays in all-solid-state battery commercialization, weaker-than-expected customer validation, and risks in mass-production technology or cost control.

Key data

• Report date2026-05-22The report body shows Equity Research 22 May 2026 1:11AM JST.
• RatingBuyGoldman Sachs maintains a Buy rating on Mitsui Kinzoku.
• 12-month target price¥44,100The target price comes from the price target, risk, and methodology sections.
• FY3/31 company-wide recurring profit target¥1500亿The company target is composed of about ¥1300亿 from engineered materials and about ¥200亿 from the metals business.
• FY3/31 engineered materials recurring profit target¥1300亿The copper foil business is expected to contribute about ¥1000亿 of that.
• FY3/31 metals business recurring profit target¥200亿The plan assumption is conservative; under current market conditions, recurring profit could reach about ¥600亿, corresponding to roughly 20% ROIC.
• FY3/31 ROIC target20%Raised from the previous 14%.
• FY3/31 ROE target16%Raised from the previous 14%.
• Copper foil business ROIC target64%Raised from the previous 49%.
• Metals business ROIC target8%Raised from the previous 7%.
• MicroThin FY3/27 sales growth expectation+13% yoySlower than the prior year's +45% yoy, but raised by about 15% versus the previous outlook.
• MicroThin capacity-related number5.6 million square meters/monthManagement wants optionality prepared for further upside.
• VSP FY3/27 capacity target782 tons/monthRaised from 512 tons/month, with the report citing about 43% YoY growth.
• VSP FY3/28 outlook900 tons/monthGoldman Sachs considers this outlook very conservative.
• High-grade electrolytic copper foil market forecastaround 5,000 tons/month in CY28About 6,000 tons/month after yield adjustment; the scope is HVLP3 and above.
• Mitsui Kinzoku announced capacity1,200 tons/month as of Sep 2028Goldman Sachs believes the company's market share could fall significantly from current levels based on that capacity.
• VSP ultra-high-grade product salesabout 2.5x yoyHVLP4 and above products are expected to account for nearly half of total sales.
• A-SOLiD supply capacitySupply-capacity quadrupling measures completedFor supplying commercialization customers in all-solid-state batteries in 2027-2028.
• A-SOLiD mass-production verificationTarget to start verification operations in 2027The initial mass-production technical verification facility has already broken ground, supported by METI battery supply assurance project subsidies.

Impact & implications

If Mitsui Kinzoku can rapidly expand high-performance VSP copper foil capacity while simultaneously advancing MicroThin and A-SOLiD, the market may further assign it valuation characteristics tied to AI servers, semiconductor materials, and next-generation battery materials rather than treating it as a traditional metals and materials company. Conversely, if excessive emphasis on ROIC delays investment decisions, the company could lose share during the rapid expansion cycle of the high-grade electrolytic copper foil market, limiting corporate value enhancement.

Risks

• A slowdown in AI server demand could weaken the growth case for MicroThin and VSP.
• Yen appreciation could affect overseas revenue translation and profitability.
• Declines in zinc and other metal prices could weigh on metals business profit and cash flow.
• If management delays large-scale VSP investment because of ROIC constraints, the company may lose share in the high-grade electrolytic copper foil market.
• A-SOLiD still faces uncertainties around all-solid-state battery commercialization, customer adoption, and mass-production verification.
• The report includes Goldman Sachs' and the covered company's shareholding, client relationship, and other potential conflict-of-interest disclosures.

What to watch

• Whether the company announces further VSP expansion plans, including converting non-VSP capacity, building new facilities in-house, or pursuing M&A.
• Whether VSP capacity can rise materially above the conservative 900 tons/month outlook after FY3/28.
• Whether HVLP4-and-above ultra-high-grade product sales can expand by about 2.5x as planned and approach half of total sales.
• Whether MicroThin sees demand upside beyond the assumption of 5.6 million square meters/month.
• Whether metals business cash flow is reallocated to engineered materials as planned, rather than becoming a standalone growth driver.
• Whether A-SOLiD's initial mass-production technical verification facility starts verification operations as planned in 2027.
• The actual commercialization pace of AI servers, storage, high-speed optical transceivers, flexible printed circuits, and all-solid-state batteries.