SEM Holdings Limited, an investment holding company, engages in the provision of electrical and mechanical (E&M) engineering services in Macau and Hong Kong. The company is involved in the supply, installation, and maintenance electrical systems for new and existing buildings in the projects of commercial and residential development, hotel and casino development, sports venues, public properties, and hotel renovation. It serves contractors or the E&M engineering works subcontractors in the related development and renovation projects. The company was founded in 2006 and is headquartered in Chai Wan, Hong Kong. SEM Holdings Limited operates as a subsidiary of SEM Enterprises Limited.