| HK SERMA ELECTRONICS LIMITED | Private company limited by shares | Dissolved |
| SERMA INTERNATIONAL COMPANY LIMITED | Private company limited by shares | Live |
| SERMAN LIMITED | Private company limited by shares | Live |
| SERMAN INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| SERMAR CO., LIMITED | Private company limited by shares | Live |
| SERMART INDUSTRIAL LIMITED | Private company limited by shares | Live |
| SERMATA COMPANY LIMITED | Private company limited by shares | Dissolved |
| SERMAX LIMITED | Private company limited by shares | Dissolved |
| SERMAX INVESTMENTS LIMITED | Private company limited by shares | Dissolved |