Whitepaper thesis: AI rack densities push past 1 MW; the only economic answer is 800 VDC bus distribution + integrated storage, with MV → DC conversion as the long-term endgame. This collapses the AC distribution layer and creates demand pulls in five places:
- High-frequency, high-voltage power devices — SiC MOSFETs / GaN HEMTs for the 800V → 12V (64:1) LLC converters. The whole architecture rides on SiC switching efficiency.
- MW-scale AC/DC rectifiers (5×3.5 MW per power block) and eventually MV rectifiers / solid-state transformers at 7.5 MW @ ≥98.5%.
- DC switchgear and solid-state breakers + 1500 A busducts.
- Layered energy storage — capacitors (≤100 ms), supercaps (100 ms-10 s), batteries (>10 s) — at rack and facility level.
- Grid-forming / VRT-capable interconnect + control plane that lets DCs become grid-supporting assets.
This brief ranks the 43-name shortlist by 800 VDC leverage, then for each Tier A/B name pulls segment-level revenue / growth / margin from the latest 9M FY2025 tanshin (tdnet fs CODE seg), so we can see what % of consolidated revenue actually rides the theme.
| Tier | Code | Name | Why they win | Why they don't |
|---|---|---|---|---|
| A | 6963 | ROHM | Only JP pure-play SiC IDM (substrate→device); LLC converter sweet spot | Discrete segment still loss-making; auto cycle drag |
| A | 6504 | Fuji Electric | IGBT/SiC modules + AC/DC power supplies + EV chargers — three of the five demand-pulls in one company | Semi segment in cyclical reset; auto-IGBT inventory drag |
| A | 6503 | Mitsubishi Electric | Power semi + GIS / HVDC switchgear + SST roadmap — most complete stack | Conglomerate dilution; HVAC dominates earnings |
| A | 6890 | Ferrotec | SiC substrate via FLH (China); thermal stages + quartz for SiC fabs | China geopolitical risk; substrate pricing volatile |
| A | 6920 | Lasertec | SiC inspection — every new SiC fab buys these tools | EUV mask cycle currently dominates revenue, masks the SiC opportunity |
| A | 6882 | Sansha Electric | Pure-play industrial DC power supplies + EV chargers + semi process power — direct rectifier-block fit | Tiny ¥18B revenue; semi seg still loss-making |
| A | 6844 | Shindengen | Power devices + DC/DC converters; explicit "power-device new co" capex disclosures | Auto-electrification cycle dependent; small fwd P/E hides cyclical earnings |
| A | 6501 | Hitachi (Hitachi Energy) | HVDC, transformers, grid automation, MV rectifier roadmap — direct fit for facility-level + MV stages | HE only ~20% of consolidated; segment data not in JP tanshin |
| B | 6508 | Meidensha | Substation transformers + eco-switchgear + drives — bullseye for the MV side | Mid-cycle margins; switchgear seg still loss-making |
| B | 6622 | Daihen | RF generators (semi etch power) + transformers + welding power | Small DC-data-center exposure; semi-cap cycle exposed |
| B | 5333 | NGK Insulators | NAS battery (grid storage) + ceramics (insulators, SiC substrates) | NAS in slow secular decline vs Li-ion; energy seg sub-scale |
| B | 5310 | Toyo Tanso | Graphite for SiC epi growth — direct upstream consumable | Single product line; SiC seg not separately broken out |
| B | 6864 | NF Holdings | Lab/grid power supplies, frequency converters | Tiny ¥10B mcap; segments not disclosed |
| B | 6707 | Sanken | Power IC, motor-drive ICs (post-Allegro spin) | Single semi segment; restructuring noise |
| B | 485A | Power X | BESS (Mega Power) + ultra-fast EV chargers (Hypercharger) — 800 V architecture native | Pre-profit scaling; consolidated loss -¥5B |
| C | 6617 | Takaoka Toko | Transformers — grid capex tailwind | Less DC-specific; smart-meter mix |
| C | 6643 | Togami | Switchgear | Smaller, less DC-specific |
| C | 6507 | Sinfonia | Drives, motors | Industrial — not directly 800VDC |
| C | 6768 | Tamura | Coil transformers + power supplies | Small-coil, not MW-scale |
| C | 4966 | Uyemura | Plating chemistry | Pass-through volume play |
| C | 4062 | Ibiden | IC substrates | Compute-side, not power |
| C | 3445 | RS Tech | Reclaimed wafer + SiC adjacency | Indirect |
| C | 6928 | Enomoto | Lead frames | Volume play |
| C | 6140 | Asahi Diamond | SiC dicing wheels | Consumable |
| D | 6266 / 6291 / 6337 / 6590 / 6728 | Semi cap eq | Generic semi capex beneficiary | Not 800VDC-specific |
| D | 6742 | Kyosan | Rail signaling | Wrong vertical |
| D | 9501 / 9502 | TEPCO / Chubu | Demand-side beneficiary | Slow regulated growth |
| D | 9517 | eRex | Power retail | No HW exposure |
| D | 1942 | Kandenko | DC build-out contractor | Indirect; capex deflator |
| D | 1436 / 4169 / 3083 / 3121 / 3260 / 3913 | Pivots | Narrative play | Pre-revenue speculation |
| D | 6981 | Murata | Capacitors (relevant!) | Capacitor exposure not driving consolidated; mainly mobile/MLCC |
All tables are 9M FY2025 (Apr-Dec 2025) vs 9M FY2024, ¥M unless noted, from each company's latest 3Q tanshin (segments/<code>.seg).
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY24 | Profit 9M-FY25 | Margin 9M-FY25 |
|---|---|---|---|---|---|---|
| LSI | 155,888 | 169,360 | +8.6% | 3,986 | 19,937 | 11.8% |
| 半導体素子 (Discrete — SiC/IGBT/MOSFET) | 144,128 | 155,837 | +8.1% | −20,493 | −16,488 | −10.6% |
| モジュール | 25,664 | 24,915 | -2.9% | 2,710 | 3,011 | 12.1% |
| その他 (resistors) | 18,960 | 19,401 | +2.3% | 1,890 | 3,332 | 17.2% |
| Consol | 344,642 | 369,515 | +7.2% | −11,080 | +9,703 | 2.6% |
- Target segment: 半導体素子 (Discrete) — houses the SiC MOSFET line. 42% of consolidated revenue.
- Read: Discrete is still loss-making (-10.6% margin) but the loss narrowed from −¥20.5B to −¥16.5B on +8% revenue. The SiC capex amortization is the drag; the question is when SiC volume ramps faster than D&A. The whole equity story is whether Discrete returns to positive margin within FY26-27. 800 VDC architecture pull is a fresh demand vector that wasn't in the auto-only thesis.
- Caveat: ROHM also changed depreciation method (定率→定額) which boosted Discrete profit ¥5.4B — half of the apparent improvement is accounting.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY24 | Profit 9M-FY25 | Margin 9M-FY25 |
|---|---|---|---|---|---|---|
| エネルギー (T&D, EV chargers, BESS) | 229,553 | 255,690 | +11.4% | 20,269 | 33,085 | 12.9% |
| インダストリー (Drives, automation) | 286,756 | 319,128 | +11.3% | 17,126 | 19,749 | 6.2% |
| 半導体 (IGBT/SiC modules) | 164,028 | 170,552 | +4.0% | 21,543 | 14,987 | 8.8% |
| 食品流通 (Vending) | 83,991 | 77,936 | -7.2% | 12,274 | 9,319 | 12.0% |
| その他 | 26,733 | 27,746 | +3.8% | 2,427 | 2,539 | 9.2% |
| Consol | 791,064 | 851,055 | +7.6% | 68,431 | 74,027 | 8.7% |
- Target segments: エネルギー + 半導体 = ¥426B = 50% of consolidated revenue.
- Read: エネルギー is the standout — +11% revenue, +63% segment profit YoY, margin from 8.8% to 12.9%. This is where DC PSU / EV charger / grid storage demand lands. 半導体 is in a cyclical reset (margin 13.1% → 8.8%) on auto IGBT inventory; the SiC module ramp is the next-leg story.
- Caveat: Energy seg includes traditional T&D and food-vending HVAC — not a pure DC play. Need MD&A to break out DC PSU.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | OP 9M-FY24 | OP 9M-FY25 | Margin 9M-FY25 |
|---|---|---|---|---|---|---|
| インフラ (T&D, GIS, HVDC, defense) | 789,048 | 926,454 | +17.4% | 47,662 | 79,281 | 8.6% |
| インダストリー・モビリティ (FA, EV) | 1,205,804 | 1,202,091 | -0.3% | 64,740 | 94,157 | 7.8% |
| ライフ (HVAC) | 1,625,061 | 1,670,294 | +2.8% | 139,649 | 136,034 | 8.1% |
| デジタル | 57,182 | 57,702 | +0.9% | 6,915 | 7,293 | 12.6% |
| セミコンダクター・デバイス (SiC, IGBT, opto) | 194,680 | 188,735 | -3.1% | 31,884 | 35,120 | 18.6% |
| その他 | 128,576 | 110,734 | -13.9% | 43,100 | 41,640 | 37.6% |
| Consol | 4,000,351 | 4,156,010 | +3.9% | 303,555 | 294,757 | 7.1% |
- Target segments: インフラ + セミコンダクター = ¥1,115B = 27% of consolidated revenue.
- Read: インフラ is the breakout — +17% revenue, +66% profit YoY. Hitachi Energy's success is bringing demand to MELCO too on transformers and GIS for DC connections. Semi is a small but high-margin slice (18.6%) where SiC mix is driving the resilience despite revenue dip. Combined target seg margin ~10%.
- Caveat: HVAC (ライフ) is still ~40% of revenue and ~46% of profit; for the 800 VDC theme to move the consolidated needle, インフラ needs to keep compounding at this rate.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY24 | Profit 9M-FY25 | Margin 9M-FY25 |
|---|---|---|---|---|---|---|
| 半導体等装置関連 (Semi eq + SiC substrate FLH) | 122,784 | 134,314 | +9.4% | 10,838 | 12,487 | 9.3% |
| 電子デバイス (Power-semi substrates, thermal) | 36,303 | 41,963 | +15.6% | 5,923 | 8,837 | 21.1% |
| 車載関連 | 23,127 | 22,477 | -2.8% | 2,837 | 2,008 | 8.9% |
| その他 (saw blade, solar Si) | 20,150 | 12,890 | -36.0% | 624 | -169 | neg |
| Consol | 202,365 | 211,645 | +4.6% | 19,696 | 21,840 | 10.3% |
- Target segments: Semi-related + Electronic Devices = ¥176B = 83% of consolidated revenue.
- Read: Electronic Devices (where the FLH SiC substrate spin-off sits) grew +16% with margin expansion 16.3% → 21.1%. Semi-related grew +9% with margin steady at 9.3%. This is the cleanest pure-play exposure on the JP shortlist by % of revenue.
- Caveat: China-domiciled subsidiary risk; SiC wafer pricing has been weak globally — the volume is the story, not ASP.
- Single-segment (検査・測定装置). 9M-FY26 (Jul-Dec 2025) revenue ¥51.8B (-19.7% YoY), op profit ¥18.0B (-22%) per
out/6920.md. The decline reflects EUV mask inspection cycle. - Read: SiC inspection is a small but explicitly-disclosed product line (typically <10% of revenue from the IR deck, not separately segmented). The 800 VDC pull is a multi-year option, but Lasertec's near-term P&L is dominated by the EUV cycle.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY24 | Profit 9M-FY25 | Margin 9M-FY25 |
|---|---|---|---|---|---|---|
| 半導体事業 (Semi process power) | 4,367 | 4,582 | +4.9% | -419 | -511 | -11.2% |
| 電源機器事業 (Industrial power supplies, EV chargers) | 13,568 | 13,597 | +0.2% | 1,037 | 858 | 6.3% |
| Consol | 17,936 | 18,180 | +1.4% | 618 | 347 | 1.9% |
- Target segment: 電源機器 = 75% of revenue.
- Read: Pure-play but tiny (¥18B) — at this scale, a single 800VDC AI-DC contract win is transformative. Margin compressed YoY (7.6% → 6.3%); semi seg still loss-making. Highest revenue-leverage on a beneficiary basis but smallest absolute exposure.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY24 | Profit 9M-FY25 | Margin 9M-FY25 |
|---|---|---|---|---|---|---|
| パワーデバイス事業 | 23,271 | 24,525 | +5.4% | -348 | 1,969 | 8.0% |
| パワーユニット事業 (DC/DC, motorcycle/EV) | 49,911 | 53,878 | +7.9% | 3,854 | 2,981 | 5.5% |
| パワーシステム事業 | 4,310 | 5,304 | +23.1% | 808 | 969 | 18.3% |
| Consol | 77,611 | 83,807 | +8.0% | 758 | 3,117 | 3.7% |
- Target segments: All three = 100% of revenue — Shindengen is fully in scope.
- Read: Power Device segment swung from loss to +¥2B profit (margin ~8%). Recent filings explicitly disclose new "power-device new co" stock acquisition (Jan 2026) — tells you management is doubling down. Power System is small but margin 18% — could be the AI-DC PSU sub-line.
- Caveat: EV motorcycle exposure (Honda) is the dominant Power Unit driver — not DC bus.
- Tanshin doesn't disclose segments at this granularity (Hitachi reports under their own IFRS structure). From the latest IR deck:
- Hitachi Energy: revenue ~$13B FY24, expected ~$15-17B FY25, EBITA margin expanding 11% → 14%, 5-year orders backlog, capex tripling to expand transformer / HVDC capacity.
- Hitachi consolidated: ¥9.7T revenue → HE ≈ 20% of group, but ~30% of operating profit growth in FY24-25.
- Read: The single largest absolute-yen beneficiary on the list. 800 VDC architecture demands MV transformers + grid-forming inverters + grid automation — exactly Hitachi Energy's catalog. Backlog is the constraint, not demand. But you only get 20-cent dollars of HE through the parent.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY25 | Margin |
|---|---|---|---|---|---|
| 電力インフラ事業 | 58,336 | 69,068 | +18.4% | 7,694 | 11.1% |
| 社会システム事業 | 52,591 | 55,566 | +5.7% | -1,707 | -3.1% |
| 産業電子モビリティ | 50,454 | 46,492 | -7.9% | -1,037 | -2.2% |
| フィールドエンジニアリング | 24,837 | 27,673 | +11.4% | 3,966 | 14.3% |
| 不動産 | 2,397 | 2,396 | flat | 1,059 | 44.2% |
| Consol | 191,083 | 203,855 | +6.7% | 7,082 | 3.5% |
- Target segment: 電力インフラ = 34% of revenue.
- Read: Power infrastructure had the standout — +18% revenue, ~50% profit growth, margin 11.1%. Direct beneficiary of US/JP transformer shortage. The other segments (社会システム, 産業電子モビリティ) are loss-making and dragging consolidated margin to 3.5%. A clean pure-play in this one segment if you back it out.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY25 | Margin |
|---|---|---|---|---|---|
| エネルギーマネジメント (Transformers + power systems) | 83,810 | 86,659 | +3.4% | 9,634 | 11.1% |
| ファクトリーオートメーション (welding) | 21,441 | 22,534 | +5.1% | 738 | 3.3% |
| マテリアルプロセシング (RF generators for semi etch) | 50,429 | 54,080 | +7.2% | 5,461 | 10.1% |
| Consol | 155,825 | 163,423 | +4.9% | 12,478 | 7.6% |
- Target segments: Energy Mgmt + Material Processing = 86% of revenue.
- Read: Energy Mgmt is the transformer/HV side (+3% rev, 11% margin). Material Processing is RF generators for semi etch — semi-cap cycle beneficiary, +7% rev, 10% margin. Both are in scope but for different reasons (HV grid + SiC fab capex). Solid mid-cycle margins; less explosive growth than Meidensha or Hitachi Energy.
| Segment | Rev 9M-FY24 | Rev 9M-FY25 | YoY | Profit 9M-FY25 | Margin |
|---|---|---|---|---|---|
| エンバイロメント (auto-cat substrate) | 288,567 | 293,110 | +1.6% | 54,108 | 18.5% |
| デジタルソサエティ (semi/electronics ceramics) | 123,937 | 149,132 | +20.3% | 20,095 | 13.5% |
| エネルギー&インダストリー (NAS battery + insulators) | 42,946 | 45,666 | +6.3% | -850 | neg |
| Consol | 455,451 | 487,908 | +7.1% | 73,048 | 15.0% |
- Target segment: E&I = 9% of revenue, loss-making. Semi/digital is the actual growth engine (+20%, 13.5% margin) but that's AI-DC compute side, not 800VDC power.
- Read: NGK is mis-tagged for this theme. NAS battery is sub-scale and loss-making; the real story is the auto-catalyst substrate franchise + semi ceramics. Don't buy NGK on the 800 VDC thesis.
- Reports by geography (Japan / US / Europe / Asia), not by product. SiC graphite is embedded in Japan + Asia revenue but not separately disclosed.
- 9M-FY25 (Jan-Sep 2025) consolidated revenue ¥46.2B (vs ¥53.1B prior 9M, -13.0%), op profit ¥6.8B. Margin holding ~14%.
- Read: Generic graphite cycle dominates near-term P&L. SiC is the option value. Without segment disclosure, hard to size — depends on management commentary in the IR deck.
- Single-segment reporter; no useful breakdown. ¥10B mcap, P/B 0.8, profit small. Frequency converters and lab power supplies — too small to be a serious 800 VDC vendor at scale, but a watchlist name on takeover/concentration optionality.
- Single-segment (半導体デバイス事業). Post-Allegro spin, the consolidated business is power IC + motor-drive ICs + LEDs. 9M-FY25 revenue declined; management noted auto inventory adjustment. Margin recovery is the swing factor, not the 800 VDC theme directly.
| Segment (FY24 = full year) | Revenue | Seg Profit | Margin |
|---|---|---|---|
| BESS (Mega Power, Cube) | 4,143 | 855 | 20.6% |
| EVCS (Hypercharger) | 1,628 | -498 | neg |
| 電力 (energy retail) | 389 | -55 | neg |
| Consol (after corp ¥5.2B) | 6,161 | -4,942 | neg |
- Read: BESS unit economics already work (+21% margin). EV charging is the burn item. Consolidated still loss-making by ¥5B/yr on corporate overhead. The cleanest "800 VDC pure-play architecture" name on the screen — Hypercharger uses 800V DC bus directly. Risk: small float, IPO-vintage scaling, no AI-DC reference customer disclosed yet (IIJ协业 announced 2026-02).
For Tier A/B, the "target segment" rolled up:
| Code | Name | Target seg(s) | % of rev | Seg YoY | Seg margin | Conviction |
|---|---|---|---|---|---|---|
| 6963 | ROHM | Discrete (SiC/IGBT) | 42% | +8% | −11% | High option value, low quality today |
| 6504 | Fuji Electric | Energy + Semi | 50% | +9% | 11% | High — Energy seg is actually inflecting |
| 6503 | Mitsubishi Electric | Infra + Semi-Device | 27% | +13% | 10% | High — Infra +17% / +66% profit |
| 6890 | Ferrotec | Semi-eq + EDevice | 83% | +11% | 12% | High — most concentrated exposure |
| 6920 | Lasertec | (single seg) | 100% | -20% | 35% | Mid — EUV cycle masks SiC pull |
| 6882 | Sansha | Power Equipment | 75% | flat | 6% | Mid — small, watchlist for contract wins |
| 6844 | Shindengen | All three | 100% | +8% | 4% | Mid — auto-electrification dependent |
| 6501 | Hitachi | Hitachi Energy | ~20% | ~+20% | 14% | High — backlog is the constraint |
| 6508 | Meidensha | 電力インフラ | 34% | +18% | 11% | High — purest mid-cap HV play |
| 6622 | Daihen | Energy + Material | 86% | +5% | 10% | Mid — solid, less explosive |
| 5333 | NGK | E&I | 9% | +6% | neg | Low — mis-tagged for this theme |
| 5310 | Toyo Tanso | (no breakout) | n/d | -13% (consol) | 14% | Low-mid — option only |
| 6864 | NF Holdings | (single) | 100% | small | mid | Low — too small |
| 6707 | Sanken | (single semi) | 100% | declining | mid | Low — restructuring noise |
| 485A | Power X | BESS+EVCS | 100% | growing | seg+, consol- | Speculative — pure architecture native |
- Hitachi Energy (via 6501) — best-in-class margin trajectory in the right business, but you only get 20-cent dollars of it through the parent. Best name if you want quality.
- Meidensha (6508) — only mid-cap with a single segment delivering +18% rev / 11% margin in the exact right business. Best pure-play.
- Mitsubishi Electric Infra (6503) — +17% rev, +66% profit, 8.6% margin and accelerating. Best risk-adjusted because of conglomerate underwriting.
- Fuji Electric Energy (6504) — +11% rev, +63% profit YoY. Cheapest of the big 3 (fwd P/E 19.9 in
index.md). - Ferrotec (6890) — purest by % of revenue exposed, but China FLH execution is the swing factor.
- NGK (5333) — tagged by the screen but the relevant segment (E&I, NAS battery) is loss-making and only 9% of revenue. Don't buy this on the theme.
- ROHM (6963) — best long-dated SiC option but Discrete segment is still −11% margin and depreciation accounting boosted reported numbers ¥5.4B. Need to see real margin expansion in next 2-3 quarters.
- Lasertec (6920) — SiC tools are real but lost in EUV-cycle noise; near-term P&L will mislead the thesis.
- Pivots (Tier D) — speculative; not playable on fundamentals.
- Source data:
segments/<code>.seg - Per-ticker profile:
out/<code>.md - Methodology:
notes.md - Supply-chain map:
supply-chain-brief.md