AI screening example · run on October 12, 2026

Data center liquid cooling stocks,
across all of Japan.

We looked for companies already selling the parts and materials that cool AI data center servers with liquid. Katana kept 42 companies whose annual reports use liquid-cooling terms, and AI read each one and supported 6.

Background

Liquid cooling is arriving in Japan's data centers.

On October 7, 2026, MC Digital Realty (MCDR), a 50/50 joint venture of Mitsubishi Corporation and Digital Realty, announced it had started building its KIX15 data center in Ibaraki, Osaka. The 24 MW facility is scheduled to open in the fourth quarter of 2028 and supports hybrid air and liquid cooling.

AI processors run hot. Water cooling, which pumps coolant through cold plates mounted on the chips, removes heat far better than fans blowing air. In January 2026, research firm Dell'Oro Group forecast that the data center liquid cooling market roughly doubled in 2025 to nearly $3 billion and will grow to about $7 billion by 2029, calling liquid cooling a requirement for large-scale AI deployments rather than an optional efficiency upgrade.

So which Japanese companies actually sell the parts and materials for liquid cooling? We searched annual reports with Katana.

01 / Input

The companies we wanted to find.

“We want companies that make products, parts or materials used to cool AI data center servers with liquid, such as water-cooling modules, cold plates, coolant distribution units (CDUs), liquid-cooling racks, piping and coolants. We want to narrow it to companies that have already started shipping or mass-producing them, not just researching them.”

Entered in Japanese; English translation.

We used a word condition to keep companies whose annual reports use liquid-cooling terms, turned this profile into two questions entered in English, and had the AI read each report, question by question.

02 / Conditions

The conditions we applied across Japan.

Quantitative

Katana computes its metrics for every company.

Annual report mentions any of six liquid-cooling terms (liquid cooling, water cooling, immersion, coolant, liquid-based cooling, CDU)

Qualitative

AI reads each annual report and judges support and counterevidence.

Does the company sell products, components, or materials used to liquid-cool data center servers (e.g., cold plates, water-cooling modules, coolant distribution units, liquid-cooled racks, piping, coolant fluids)?
Has it already started commercial shipments or mass production of these, rather than only research or development?

The questions were entered in English and judged in order.

~3,800listed companies

42match the numbers

6AI judged as supported

Katana

read the filings and supported 6.

03 / Results

6 supported. We checked them, plus Furukawa Electric, against the source.

Of 42 companies, 6 were supported, 9 need review and 27 had counterevidence. Many in the last group use the same words in another sense, such as immersion lithography in chipmaking or water cooling in EVs and steelmaking. Below are the 6 supported companies and Furukawa Electric, which needs review.

Nidec6594 · Electric Appliances

Started running an in-row CDU at the Digital Realty Innovation Lab inside an MC Digital Realty data center, and completed a CDU for Google's OCP-based Deschutes project.Filing ↗A motor maker developing CDUs and liquid-cooling modules for AI servers. Its CDU went live in a lab inside a data center run by MC Digital Realty, the company building KIX15.
Sanoh Industrial6584 · Transportation Equipment

Finished developing ball-valve fittings and shut-off connectors for data center liquid cooling in April 2025, and won orders for water-cooling modules and fittings from several domestic customers in September 2025.Filing ↗An automotive tubing maker that applied its piping know-how to data center water cooling, winning orders from several domestic customers in September 2025.
Furukawa Electric5801 · Nonferrous Metals

Expanded its water-cooling module plant in the Philippines and added equipment at its Hiratsuka plant, preparing for mass production from September 2026.Filing ↗Judged as needing review. Its report describes expanding its water-cooling module plant and preparing for mass production. In March 2026 it announced a plan for ¥400 billion in water-cooling module sales by fiscal 2030.
Nitto Kogyo6651 · Electric Appliances

Offers heat-management products such as racks for liquid-cooled servers and racks with water-cooled rear-door units for data centers.Filing ↗A switchboard maker offering racks for liquid-cooled servers and racks with water-cooled rear doors for data centers.
Fujikura5803 · Nonferrous Metals

Is improving a new cold plate and a 3D vapor chamber to handle the rising heat of CPUs and GPUs used for generative AI.Filing ↗An optical fiber maker working on cold plates for CPUs and GPUs. Its report also uses liquid cooling for EV fast-charger cables.
Cosmo Energy Holdings5021 · Oil & Coal Products

Has built a lineup of immersion cooling fluids for data centers under the Cosmo Thermal Fluid name.Filing ↗An oil refiner and marketer with a series of fluids for immersion cooling, where servers are submerged in liquid.
Panasonic Holdings6752 · Electric Appliances

Developed a next-generation coolant circulation pump for liquid-cooled data centers.Filing ↗Its pump business developed a next-generation coolant circulation pump for liquid-cooled data centers. The report goes as far as saying it was developed.

View detailed results

These results are from October 12, 2026. Qualitative judgments use the filings available at that time, while quantitative screening uses the latest financial data.

04 / Takeaway

Liquid-cooling suppliers are still ramping up.

For the 6 supported companies and Furukawa Electric, we lined up how far each annual report says its liquid-cooling business has come.

Company	What it sells	Stage stated in the report
Nidec	CDUs, liquid-cooling modules	CDU running at an MC Digital Realty facility
Sanoh Industrial	Water-cooling modules, fittings	Orders from several domestic customers, Sept. 2025
Furukawa Electric	Water-cooling modules	Preparing for mass production from Sept. 2026
Nitto Kogyo	Racks for liquid-cooled servers	Products on offer
Cosmo Energy Holdings	Immersion cooling fluids	Product lineup built
Panasonic Holdings	Coolant circulation pumps	Developed
Fujikura	Cold plates	Improving performance

Only Nidec and Sanoh say their products are running in a real data center or have won orders. The rest are offering products, developing them or preparing mass production.

Furukawa Electric has the biggest plan. In March 2026 it announced water-cooling module sales of over ¥100 billion in fiscal 2027 and ¥400 billion in fiscal 2030, about 30% of its ¥1.31 trillion revenue for the year ended March 2026.

Conversely, Fujitsu, NEC and NTT, often named as liquid-cooling data center stocks, never mention liquid or water cooling in the main sections of their annual reports. KDDI writes about liquid cooling as a user in its own data centers. Lists of theme stocks and the businesses described in filings do not always overlap.

Source：Capital investment in heat dissipation and cooling products for data centers (Furukawa Electric, March 30, 2026, in Japanese)

Your stock-picking, handed straight to AI.

Complex theses, your own selection rules. Katana narrows companies with its own metrics, and AI reads annual reports to judge qualitative conditions. The selection you used to do one company at a time, AI now runs across the Japanese market.

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