| CASTOR COMPANY LIMITED | Private company limited by shares | Dissolved |
| Castor Limited | Private company limited by shares | Live |
| CASTOR LIMITED | Private company limited by shares | Live |
| CASTOR HOLDING LIMITED | Private company limited by shares | Live |
| CASTOR INVESTMENTS LIMITED | Private company limited by shares | Live |
| HONGKONG CASTOR AND POLLUX MARINE & OFFSHORE TECHNOLOGY LIMITED | Private company limited by shares | Live |
| Castor Advanced Solutions Limited | Private company limited by shares | Dissolved |
| CASTORES MAGI (HONG KONG) LIMITED | Private company limited by shares | Live |
| CASTORES MAGI ASIA LIMITED | Private company limited by shares | Live |
| CASTORP LIMITED | Private company limited by shares | Dissolved |
| British Castors Limited | Private company limited by shares | Live |