Diamond Electric Holdings Co., Ltd. manufactures and sells automotive electronic components, energy solutions, and electronic control devices primarily in Japan and overseas markets. The company produces ignition coils including pencil coils, square coil-on-plug types, and those with ion current detection; automotive electrical equipment such as DC-DC converters for hybrid vehicles and idling stops, air conditioner controllers, body control units, on-board chargers, rotation sensors, harness assemblies, and transmission switches; energy solutions encompassing solar inverters, hybrid battery systems, and TABUCHI-cloud remote monitoring services; and electronic control products like high voltage generators, power devices including reactors, choke coils, inductors, transformers, and coils for IH cookers. Incorporated in 2018 and headquartered in Osaka, Japan, it operates factories and sales offices across Japan, the United States including West Virginia and Michigan, Hungary, Thailand, China, India, Vietnam, Indonesia, and South Korea. Recent developments include a ransomware incident at an overseas subsidiary reported in November 2025, financial results revisions for fiscal year 2024/2025 boosting profitability, capital reserve reduction, year-end dividend announcements, and funding provided to subsidiary Diamond Electric Asia Pacific Co., Ltd.