KOHOKU KOGYO CO.,LTD.
6524・Standard Market・Electric Appliances
Business
Kohoku Kogyo Co., Ltd. is an electronic components manufacturer founded in 1959, headquartered in Nagahama City, Shiga Prefecture, forming a group that includes 7 consolidated subsidiaries. Its core businesses consist of two pillars: the manufacture and sale of lead terminals, which are key components of aluminum electrolytic capacitors (Lead Terminal Business), and the manufacture and sale of optical components and devices such as Optical Isolators for submarine cables (Optical Components & Devices Business). Lead terminals are supplied to all Japanese capacitor manufacturers as well as Taiwanese, Korean, and Chinese capacitor manufacturers, and the company holds a high global share in Optical Isolators for submarine cables. Major customers include Alcatel Submarine Networks UK Ltd. (20.0% of net sales) and SubCom, LLC (16.5% of net sales), with the expansion of the generative AI/data center market and the automotive electronics market serving as the primary growth drivers.
Business Model
In the Lead Terminal Business, the company combines an integrated production process—welding, pressing, cleaning, and chemical conversion—with in-house developed equipment and facilities to achieve stable quality with minimal variation. The company is improving its earnings structure through expanded adoption of high value-added products for high-performance capacitors and improvement of unprofitable orders. In the Optical Components & Devices Business, leveraging its strength in integrated production combining precision-shaped quartz glass manufacturing technology, magneto-optical material technology, and precision assembly technology, the company has secured a high global share in Optical Isolators for submarine cables, achieving a high operating margin of 44.6% in FY2025.
Company Strengths
The Optical Components & Devices Business achieved operating income of ¥3,857 million (operating margin of 44.6%) against net sales of ¥8,651 million in FY2025. The company holds a high global share in optical isolators that meet extremely demanding reliability requirements—8,000 meters underwater and 25 years of maintenance-free operation—and has built long-term partnerships with major submarine cable-laying companies such as Alcatel Submarine Networks and SubCom.
Since its founding in 1959, the company has maintained an integrated production system in which all manufacturing processes and equipment/facilities are designed and developed in-house. It has accumulated proprietary technologies in each of the welding, pressing, cleaning, and chemical conversion processes, and holds numerous international patents related to its technologies and products. It has obtained IATF16949 certification globally, earning high trust from the automotive industry as well.
In FY2025, orders received in the Optical Components & Devices Business reached ¥9,988 million (up 70.6% year on year), and the order backlog reached ¥4,198 million (up 46.7% year on year). Against the backdrop of active data center investment driven by the spread of generative AI, tight supply-demand conditions for Faraday Rotators have continued, and the company is responding to robust demand while expanding production capacity.
ENVALITH's Perspective
Performance Trend
Sales over the past five fiscal years bottomed out at ¥13,472 million in FY2023 and recovered to expand to ¥17,454 million in FY2025. In Q1 of FY2026 (ending December 2026), sales reached ¥4,544 million (up 27.7% year-on-year), operating profit came to ¥1,217 million (up 81.5%), ordinary profit reached ¥1,327 million (up 340.5%), and quarterly net profit attributable to owners of the parent totaled ¥897 million (up 294.0%), representing substantial profit growth at every profit level. The fact that a foreign exchange loss of ¥412 million recorded in the same period of the previous year turned into a foreign exchange gain of ¥94 million this period contributed to the sharp expansion in ordinary profit. As external factors, the yen's depreciation with an average rate of ¥156.96/dollar during the period, combined with a sharp increase in demand for optical components driven by expanding AI and data center investment, strongly supported performance. The full-year forecast (sales of ¥19,613 million, operating profit of ¥5,404 million) remains unchanged, and Q1 progress is generally in line with the plan.
Growth Strategy
Aiming to achieve medium-term targets through a three-pronged approach: deepening the GNT conglomerate, creating new businesses, and developing next-generation technologies
Advancing capacity expansion for Faraday Rotators and Optical Isolators for the data center market. Sample supply of Composite Optical Device Products & Module Products has commenced, and development of next-generation products such as fan-in/fan-out optical devices compatible with multi-core fiber is also underway. Development of high-power products for the satellite communications market has also begun.
Promoting expanded sales of high-function lead terminals (leakage current countermeasure products, low-resistance products, etc.) and management efficiency improvements through the use of ROIC indicators. Simultaneously improving the supply system and profitability through capacity expansion at the Dongguan plant in China, expansion of production items at the Malaysia plant, and OEE improvements at each plant. Development of next-generation laser welding technology is also underway.
Amid a significant increase in inquiries for quartz components and specialty optical fiber preforms for semiconductor-related applications, the company is working to expand production capacity to strengthen its stable supply system. It aims to cultivate this as a third pillar of profitability by leveraging synergies with its existing optical components technology.
Sample shipments of single-crystal PLZT thin-film wafers, which are attracting attention as a material for next-generation high-speed communication devices, commenced in Q1 2026. The company will continue efforts toward customer evaluation and mass production as a new business aimed at medium- to long-term growth.
Last updated: July 17, 2026