Mitsui Kinzoku Company, Limited
5706.TMEDIUMBattery Materials / Electrolytic Copper Foil + A-SOLiD · Weight: 3%· Data as of 2026-05-21
Investment Thesis
Renamed from Mitsui Mining & Smelting (Oct 2025). Global leader in electrolytic copper foil — the anode current collector inside every Li-ion battery cell. Near-monopoly in ultra-thin carrier copper foil (MicroThin: >90% global share in advanced PCB/packaging foil). Honda e-motorcycle supply chain link: copper foil → Panasonic cylindrical cells → Honda Mobile Power Pack (confirmed Panasonic as MPP cell supplier); ALSO → LG Energy Solution 2170 cells → Honda Vietnam Hanoi 1,000-station swap network (MOU May 2026, confirmed by TNGlobal/Electrek). Dual catalyst: (1) EV battery copper foil demand scaling with Honda Vietnam/India ramp; (2) A-SOLiD™ sulfide solid electrolyte R&D (pilot plant 2027) aligned with Honda's Jan 2025 all-solid-state battery demo line. ROE 18.4% + op margin ~15.6% = exceptional quality for materials company.
Risk
1) PB ~5x elevated vs. materials sector peers — guardrail warning (P/B above 80th percentile for cyclicals). Override: structural moat in carrier foil + ROE 18.4% justifies premium. 2) Battery copper foil moat is ★★★ (competitive vs. Korean SK Nexilis, Iljin, Chinese makers) even though carrier foil is ★★★★★ — distinguish the two segments. 3) FY2025 earnings upgrade was primarily AI server PCB foil, not EV battery foil — Honda motorcycle catalyst is medium-term, not immediate. 4) A-SOLiD ASSB is pre-commercial (pilot 2027) — speculative optionality, not revenue yet.
Monitoring Trigger
Q2 FY2026 results (Oct 2026): Check Functional Materials segment revenue split between AI server foil vs. battery foil. If battery foil >30% of segment, UPGRADE to HIGH. Honda Vietnam swap station count: if exceeds 200 by end-2026, CONFIRM supply chain ramp. A-SOLiD pilot plant announcement: if confirmed 2027 startup, UPGRADE thesis to include Honda ASSB optionality.
Key Dates
2026-10earningsH1 FY2026 earnings — check Functional Materials split: AI vs EV copper foil revenue
2026-12monitoringHonda Vietnam swap station count milestone — 200+ stations confirms e-motorcycle ramp
2027-01catalystA-SOLiD pilot plant expected startup — ASSB optionality catalyst
Update History
2026-05-21exploreNEW
View report →Added from Honda e-motorcycle explore: copper foil anode layer + A-SOLiD ASSB optionality. Honda Vietnam Hanoi 1000-station LG Energy MOU is key catalyst. PB guardrail overridden.
Key Metrics
~29.7x TTM / ~22.3x forward (StockAnalysis/Simply Wall St, May 2026)
PE
~22.3x
Fwd PE
~5x (WARNING: guardrail — above 80th percentile for materials cyclicals; justified by structural moat)
P/B
~18.4%
ROE
~15.6% (implied: OP ¥117B / revenue ¥750B FY2025E)
Op Margin
N/A
D/E
~0.6-1.1%
Div Yield
N/A (verify J-Quants; positive expected given OP margins)
FCF
~¥270B
Mkt Cap
Business Segments
| Segment | Revenue | Share | Description |
|---|---|---|---|
| Functional Materials (copper foil + battery materials) | est. ~¥200B+ | ~30%+ | Electrolytic copper foil for AI server PCB and EV battery anodes. MicroThin ultra-thin carrier foil (>90% share). A-SOLiD sulfide solid electrolyte R&D. |
| Metals (copper smelting + precious metals) | est. ~¥400B+ | ~55%+ | Traditional copper smelting, zinc processing, precious metal refining. Stable cash generation base. |
| Mobility (automotive parts + zinc die-casting) | est. ~¥100B | ~15% | Automotive parts, zinc die-casting — indirect Honda connection via automotive supply chain. |
Supply Chain Evidence
| Evidence | Customer | Product | Detail |
|---|---|---|---|
| probable | Panasonic Energy | Electrolytic copper foil for cylindrical 18650/21700 Li-ion cell anode current collector → Honda Mobile Power Pack e: cells | Panasonic is confirmed as Honda MPP cell manufacturer (Wikipedia/press releases); Mitsui Kinzoku is Japan's leading electrolytic copper foil maker; logical Tier-2 link. No named Panasonic-Mitsui Kinzoku contract found publicly.[source](2026-05) |
| probable | LG Energy Solution | Copper foil for 2170 cylindrical cells → Honda Vietnam MPP Hanoi 1,000-station swap network (MOU May 2026) | LG Energy Solution confirmed as 2170 cell supplier for Honda-Hanoi MPP swap network (May 2026 MOU). LG's Korea supply chain may use Korean foil (SK Nexilis) — not confirmed Mitsui. But Mitsui supplies global cell makers.[source](2026-05-20) |
| confirmed | AI server PCB manufacturers (via Functional Materials) | MicroThin ultra-thin carrier copper foil for advanced PCB/packaging — near-monopoly >90% global share | FY2025 earnings upgrade explicitly driven by AI server copper foil demand for VSP-grade ultra-thin foil. Current primary revenue driver.[source](2026-05) |
| inferred | Honda Motor (future — ASSB) | A-SOLiD™ sulfide solid electrolyte for all-solid-state batteries (pilot plant 2027) | Honda launched ASSB demo production line Jan 2025 targeting motorcycles and cars. Mitsui A-SOLiD pilot planned 2027. No confirmed Honda-Mitsui ASSB contract, but technology roadmap alignment is strong.[source](2024-11) |
Sources & References
↗Mitsui Kinzoku FY2025 earnings upgradehttps://www.theglobeandmail.com/investing/markets/stocks/XZJCF/pressreleases/221746/mitsui-kinzoku-lifts-fy2025-outlook-on-copper-foil-and-metal-price-tailwinds/↗Mitsui Kinzoku copper foil moat analysis (GlobalTechResearch)https://globaltechresearch.substack.com/p/mitsui-mining-and-smelting-5706-jp↗A-SOLiD sulfide solid electrolyte R&Dhttps://www.mitsui-kinzoku.com/Portals/0/resource/uploads/topics_161124e.pdf↗Honda Vietnam LG Energy Solution 1000 swap stationshttps://technode.global/2026/05/20/vietnams-hanoi-lg-energy-solution-honda-to-jointly-launch-1000-electric-motorcycle-battery-swapping-stations/↗Honda LG Energy Solution Vietnam MOU — Electrekhttps://electrek.co/2026/05/18/honda-and-lg-team-up-to-accelerate-battery-swapping-electric-motorcycles/↗Simply Wall St — 5706 metricshttps://simplywall.st/stocks/jp/materials/tse-5706/mitsui-mining-smelting-shares
Peer Comparison
| Company | PE | Fwd PE | ROE | Op Margin | FCF |
|---|---|---|---|---|---|
| Murata Manufacturing | ~49.7x TTM (impairment-distorted; fwd PE ~37x on FY2026 guidance) | ~37x (on FY2026 OP +34.8% guidance) | 7.25% | 15.4% | +¥239B |
| TDK Corp | 26.51 | 23.71 | 11.4% | 12.4% | +¥169B |
| Fuji Electric | 20.59 | 17.97 | 8.2% | 8.7% | +¥51B |
| Sumitomo Metal Mining | 28.63 | 19.76 | 5.0% | 5.0% | +¥87B |
| AGC Inc | 17.89 | 14.7 | 4.7% | 6.2% | +¥65B |
| Kureha Corp | N/A | 19 | -6.7% | -11.1% | ~est. negative (capex ongoing) |
| Asahi Kasei | 13.4 | 12.9 | 7.7% | 7.5% | +¥134B |
| Mitsubishi Electric | 32.85 | 30.6 | 10.1% | 9.1% | +¥317B |
| Nidec Corp | 6.3% | 5.0% | +¥174B | ||
| Hirose Electric | 23.3 | 23.5 | 9.0% | 20.3% | ~+¥36B |
| Sumitomo Electric | 25.5 | 29.7 | 10.2% | 8.2% | +¥102B (est.) |
| Resonac Holdings | 83.53 | ~31.6x | 5.72% | 4.3% | +¥24B |
| Rohm Co. | Loss (NI -¥158.4B SiC impairment) | ~125x (near-breakeven NI; FY2028 target >20% OP margin) | Loss | +1.6% Q3 FY2026 (recovering from -9.0% year ago) | -¥44B |
| Shindengen Electric Manufacturing Co., Ltd. | 30.8 | N/A | N/A | N/A | N/A |
| GS Yuasa Corporation | 11.04 | N/A | 9.59% | N/A | N/A |
| Mitsuba Corporation | 5.5 | N/A | N/A | N/A | N/A |
| Daido Steel Co., Ltd. | ~11x | N/A | N/A | N/A | +est. |
| Nippon Seiki Co., Ltd. | 12.45 | 12.05 | N/A | N/A | +confirmed |
| Musashi Seimitsu Industry Co., Ltd. | 31.6 | N/A | N/A | 11.1% | N/A |
| Stanley Electric Co., Ltd. | 13.8 | 4.5% | 6.3% | N/A | |
| Honda Motor Co., Ltd. | 7.77 | 5.82% | 7.0% | N/A | |
| Mitsui High-tec, Inc. | 15.3 | 13 | 11.8% | 5.8% | -¥12B |
| MinebeaMitsumi Inc. | 18.7 | 13.75 | 9.1% | 6.2% | -¥21B |
| Ryobi Limited | ~8x | N/A | 4.4% | 3.2% | N/A |
| Tokai Rika Co., Ltd. | ~8x | N/A | 10.9% | 5.9% | +est. ¥15-20B |
| Nippon Chemi-Con Corporation | 91 | 7 | 3.1% | 2.9% | ~0 (thin; ¥20B capex planned) |
| Japan Aviation Electronics Industry, Ltd. | 13.7 | 5.1% | 7.1% | thin (¥63B capex over 3yr) | |
| ARCHION Corporation | 11 | 11 | ~6% | ~2.0% | Negative on integration capex through FY2027 |
| Alps Alpine Co., Ltd. | 18.3 | N/A | N/A | 2.4% | N/A |
| Nichicon Corporation | 16.74 | N/A | N/A | 3.8% | N/A |
| Mikuni Corporation | 4.2 | N/A | N/A — confirm vs J-Quants | N/A — thin, est. 1-3% | N/A |
| T.RAD Co., Ltd. | N/A — confirm vs StockAnalysis | N/A | N/A — confirm vs J-Quants | N/A | N/A |
| Renesas Electronics Corporation | N/A (EPS negative — IDT amortization ¥370B/yr; operating profit positive) | N/A | ~10.5% (pre-impairment FY2025; currently impaired by amortization) | N/A — confirm vs J-Quants | N/A |
| Shin-Etsu Chemical Co., Ltd. | 24.79x TTM | 22.32x (pre-PVC recovery) | ~10.5-11.5% | ~24.7% (FY2026; compressed -14.4% from PVC weakness) | +¥739.4B (FY2025 — outstanding) |
| Sumitomo Bakelite Co., Ltd. | ~17.2x TTM | ~12.0x (FY2025 guidance ¥25.5B NI) | 6.54% | 10.3% (FY2025 guidance) | +¥46B est (EV/FCF 8.73x, EV ~¥400B) |
| NSK Ltd | 32.12 | 22.70 | 1.8% | 2.96% | +¥44B (est.) |
| Toray Industries Inc | 25.97 | 16.62 | 3.19% | 5.0% | N/A |
| SMC Corporation | 29.0 | 27.24 | 7.9% | N/A | +¥200B (est., high net income + minimal capex) |
| Mitsui Kinzoku Company, Limited | ~29.7x TTM / ~22.3x forward (StockAnalysis/Simply Wall St, May 2026) | ~22.3x | ~18.4% | ~15.6% (implied: OP ¥117B / revenue ¥750B FY2025E) | N/A (verify J-Quants; positive expected given OP margins) |
| UBE Corporation | ~8.4x TTM (cheaply valued) | N/A | ~5.1% (WARNING: below TSE 8% target — ROE guardrail triggered. Override: capex-heavy transition period; electrolyte growth pipeline.) | ~4.7% (thin — monitor for recovery to 7%+) | N/A (capex-heavy with Louisiana plant — verify against J-Quants when available) |
| Taiyo Yuden Co., Ltd. | 20.79x TTM (StockAnalysis, May 2026) | 27.52x (FY2026 guidance: +8% revenue, +50% OP income) | 3.92% | ~3.3% TTM (trough); guided to ~4.8–5% FY2026 on +50% OP recovery | N/A |
| F.C.C. Co., Ltd. | 9.5x | N/A | N/A | N/A | N/A |
| Nittoku Co., Ltd. | 14.12x | 15.45x | N/A | N/A | N/A |
| NOK Corporation | 15.5x | N/A | ~3-5% | 4.9% | N/A |
| Yokowo Co., Ltd. | N/A | N/A | N/A | 5.1% | N/A |
| Yamaha Motor Co., Ltd. | 7.5 | N/A | 1.4% | 5.0% | +¥52.5B |
| Hioki E.E. Corporation | 27.8x | N/A | N/A | N/A | N/A |
| Tsubakimoto Chain Co. | ~11.2x | N/A | 8.75% | ~8.1% | est. +¥20-25B |
| Central Glass Co., Ltd. | 17.7x | ~14x (26% EPS growth forecast; analyst consensus) | ~8.2% (est: NI ¥8.36B / book value ¥101B) | ~3.2% (compressed; was ~6-9% pre-Chinese LiPF6 price war) | N/A (J-Quants not available; cross-validate before entry) |
| CKD Corporation | ~36x | ~20x (analyst forecast; likely conservative given 35.7% recent earnings growth) | 9.19% | 12.4% | N/A |
| Panasonic Holdings Corporation | 32.4x | ~15x (FY2027 NI expected +2.2x from ¥75B base) | 4.77% (FY2026 trough; guided higher FY2027) | ~2.9% (FY2026: OP ¥236.4B / Revenue ¥8,049B; compressed by restructuring charges) | N/A (Panasonic Energy capex-heavy; cross-validate before entry) |
| UACJ Corporation | 15.46x | ~22x (FY2027 NI guided ¥28B from ¥38.8B; NI decline; caution) | 11.21% | ~5.4% (Q3 FY2026 9M operating profit margin improving from prior year) | N/A (capital-intensive aluminum rolling; verify before entry) |
| Kanto Denka Kogyo Co., Ltd. | N/A (loss year FY2026 due to fire). Forward PE ~32x on FY2027 guided EPS ¥118.3 | ~32x (FY2027 guided NI ¥6.8B / shares 57.46M = ¥118.3 EPS; price ¥3,775) | -4.74% (FY2026 fire loss). FY2027 guided ROE ~10% (¥6.8B NI / ¥68B book) | ~8.7% guided FY2027 (¥10B OP / ¥95B revenue). Depressed in FY2026 (fire losses) | Negative FY2026 (fire year). Recovery expected FY2027. |
| Niterra Co., Ltd. | 15.42 | 14.67 | 14.80% | ~19% (FY2027 guide: ¥150B OP / ¥790B rev) | +¥80B est. |
| Nippon Sanso Holdings Corporation | ~18.6x est. | N/A | ~10% est. | ~15-16% (Q4 FY2026: ¥56.8B / ¥361.8B) | +¥90B est. |