SU Group Holdings Limited operates in Hong Kong's security services sector, providing security-related engineering services (including integrated security management and public address systems), security guarding services, and professional screening and background verification services through its subsidiary companies. The company generates revenue through a project-based model for engineering contracts involving design, procurement, installation, and commissioning, and through recurring service delivery fees for uniformed security personnel and periodic screening work, primarily serving residential properties, commercial buildings, and institutional clients in Hong Kong. The business is characterized by concentrated customer and supplier relationships, with customer base largely dependent on major property management companies and institutional clients requiring ongoing security and engineering solutions.