| UNDERGROUND LIMITED | Private company limited by shares | Dissolved |
| GL UNDERGROUND LIMITED | Private company limited by shares | Live |
| UNDERGROUND LIMITED -THE- | Private company limited by shares | Live |
| Underground HK Limited -The- | Private company limited by shares | Live |
| Underground Chef Limited -The- | Private company limited by shares | Live |
| CHOI'S UNDERGROUND UTILITY DETECTION CONSULTANT CO. LIMITED | Private company limited by shares | Dissolved |
| GLOBAL CITY UNDERGROUND SPACE INVESTIGATIVE LIMITED | Private company limited by shares | Live |
| UNDERGROUND CLASSICS LIMITED | Private company limited by shares | Live |
| UNDERGROUND RESEARCH TECHNOLOGY CO., LIMITED | Private company limited by shares | Dissolved |
| HCC Underground Pipeline Consultant Limited | Private company limited by shares | Live |
| Creative Underground Limited | Private company limited by shares | Live |
| Underground Creative Limited | Private company limited by shares | Live |
| Underground Development Limited | Private company limited by shares | Dissolved |
| ESI Tai He Underground Space Development Limited | Private company limited by shares | Live |
| D-tech underground management Limited | Private company limited by shares | Live |
| UNDERGROUND EXPERTISE LIMITED | Private company limited by shares | Live |
| UNDERGROUND MATERIALS SUPPLY H.K. LIMITED | Private company limited by shares | Dissolved |
| UNDERGROUND TOYS (H.K.) LIMITED | Private company limited by shares | Live |
| Underground Fun (HK) Trading Limited | Private company limited by shares | Live |
| HONG KONG UNDERGROUND CABLE ENGINEERING LIMITED | Private company limited by shares | Dissolved |
| HONG KONG UNDERGROUND ENGINEERING LIMITED | Private company limited by shares | Dissolved |
| TONGJI UNDERGROUND SPACE RESEARCH INSTITUTE LIMITED | Private company limited by shares | Live |
| UNDERGROUND INTERNATIONAL LIMITED | Private company limited by shares | Dissolved |
| UNDERGROUND SOLUTIONS INTERNATIONAL LIMITED | Private company limited by shares | Dissolved |
| PATRICK YUEN UNDERGROUND DETECTION COMPANY LIMITED | Private company limited by shares | Live |
| Underground Projects Limited | Private company limited by shares | Live |
| Solar Underground Limited | Private company limited by shares | Dissolved |