| OpenRoad Education Group Limited | Private company limited by shares | Live |
| OPENROAD GROUP LIMITED | Private company limited by shares | Live |
| OPENROAD GROUP LIMITED | | Live |
| OPENROAD IMMIGRATION CONSULTANCY LIMITED | Private company limited by shares | Dissolved |
| OpenSales Foundation Limited -The- | Private company limited by shares | Dissolved |
| OPENSEA LIMITED | Private company limited by shares | Live |
| Opensense Limited | | Live |
| OPENSHAW LIMITED | Private company limited by shares | Dissolved |
| Openshow Limited | | Live |
| OPENSIDE INTERNATIONAL TRADE LIMITED | Private company limited by shares | Live |
| OPENSKOOLS LIMITED | Private company limited by shares | Live |
| OpenSky Limited | Private company limited by shares | Live |
| OPENSOFT SYSTEM COMPANY LIMITED | Private company limited by shares | Dissolved |
| OPENSOURCE.COM HK LIMITED | Private company limited by shares | Dissolved |
| OpenSpace DB Limited | Private company limited by shares | Live |
| OPENSPARK LIMITED | Private company limited by shares | Dissolved |
| OPENSPEEDY TRADING LIMITED | Private company limited by shares | Live |
| OpenST Limited | Company limited by guarantee | Live |
| OpenStack Limited | Private company limited by shares | Live |
| OPENSTAR COMPANY LIMITED | Private company limited by shares | Dissolved |
| OPENSTRAT LIMITED | Private company limited by shares | Live |
| DDC OpenStudio Media Limited | Private company limited by shares | Live |
| OPENTECH LIMITED | Private company limited by shares | Dissolved |
| OPENTECH LIMITED | Private company limited by shares | Dissolved |
| OPENTECH DEVELOPMENT LIMITED | Private company limited by shares | Dissolved |
| OPENTECH (INTERNATIONAL) LIMITED | Private company limited by shares | Live |
| OPENTECH INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| Opentech Technology Limited | Private company limited by shares | Live |
| OpenTechno Limited | Private company limited by shares | Live |
| OPENTEK LIMITED | | Live |
| OPENTEL GROUP LIMITED | Private company limited by shares | Dissolved |
| OPENTELL TRADING & INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| OPENTIDE LIMITED | Private company limited by shares | Dissolved |
| OPENTIDE INVESTMENTS LIMITED | Private company limited by shares | Live |
| OPENTIVE COMPANY LIMITED | Private company limited by shares | Dissolved |
| Opentown Internet HK Limited | Private company limited by shares | Live |
| OPENTRADE LIMITED | Private company limited by shares | Live |
| OPEN-TRADE.NET LIMITED | Private company limited by shares | Dissolved |
| Opentrey Limited | Private company limited by shares | Live |
| Opentrons Labworks HK Inc. Limited | Private company limited by shares | Live |
| OPENTTON INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| Openup Group Company Limited | Private company limited by shares | Live |
| HK OPENUP TRAVEL CO., LIMITED | Private company limited by shares | Live |
| openUU Limited | Private company limited by shares | Live |
| OPENVENTURE COMPANY LIMITED | Private company limited by shares | Dissolved |
| Openverse Limited | | Live |
| OPENVESTED LIMITED | Private company limited by shares | Live |
| OPENVIEW COMPANY LIMITED | Private company limited by shares | Dissolved |
| OPENVIEW LIMITED | Private company limited by shares | Dissolved |
| OPENVIEW SERVICE LIMITED | Private company limited by shares | Live |
| OpenVino Company Limited | Private company limited by shares | Live |
| Openvision Limited | Private company limited by shares | Live |
| OPENVOX COMMUNICATION (HONGKONG) CO., LIMITED | Private company limited by shares | Live |
| OPENWAY LIMITED | Private company limited by shares | Live |
| OPENWAY ASIA LIMITED | Private company limited by shares | Dissolved |
| OPENWAY INDUSTRIAL LIMITED | Private company limited by shares | Dissolved |
| OPENWAY INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| OPENWAY TRADING LIMITED | Private company limited by shares | Dissolved |
| OPENWEAL LIMITED | Private company limited by shares | Dissolved |
| OpenWell Technology Co., Limited | Private company limited by shares | Live |
| Open-Well Electronic & Technology Co., Limited | Private company limited by shares | Live |
| OPENWIDE INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| OPENWIN INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| Openwines Limited | Private company limited by shares | Live |
| OPENWISE INDUSTRIAL LIMITED | Private company limited by shares | Live |
| Openwit Limited | | Live |
| Openworked Limited | | Live |
| OPENWORLD LIMITED | Private company limited by shares | Dissolved |
| Openx Limited | | Live |
| OpenXMR Limited | Private company limited by shares | Live |
| OPENZIMA COMPANY LIMITED | Private company limited by shares | Live |
| OPER LIMITED | | Live |
| OPER SCI-TECH EDUCATION LIMITED | Private company limited by shares | Live |
| Oper Engineering Co Limited | Private company limited by shares | Live |
| OPER TECHNOLOGY LIMITED | Private company limited by shares | Live |
| OPERA LIMITED | Private company limited by shares | Live |
| ONE MAN OPERA LIMITED | Private company limited by shares | Live |
| Opera Box Limited | | Live |
| WAN MAN CHINESE OPERA ACADEMY LIMITED | Private company limited by shares | Dissolved |
| Hong Kong Children's Opera Academy Limited | Private company limited by shares | Live |
| Opera Academy of Hong Kong Limited | | Live |
| CANTONESE OPERA ACADEMY OF HONG KONG LIMITED -THE- | Company limited by guarantee | Live |
| YOUNG ACADEMY CANTONESE OPERA TROUPE COMPANY LIMITED -THE- | Company limited by guarantee | Live |
| CANTONESE OPERA ADVANCEMENT ASSOCIATION LIMITED -THE- | Company limited by guarantee | Live |
| OPERA ARTS OF MCF LIMITED | Private company limited by shares | Dissolved |
| OPERA ASIA LIMITED | Private company limited by shares | Dissolved |
| ART OF CANTONESE OPERA ASSOCIATION LIMITED | Company limited by guarantee | Live |
| Opera Ballet Limited | Private company limited by shares | Live |
| KIM SUM CANTONESE OPERA COMPANY LIMITED | Company limited by guarantee | Dissolved |
| GRAND CANTONESE OPERA LIMITED | Company limited by guarantee | Live |
| Successor of Cantonese Opera Co. Limited | | Live |
| CHA DUK CHANG CHILDREN'S CANTONESE OPERA ASSOCIATION LIMITED | Company limited by guarantee | Live |
| Spring-Time Chinese Opera Limited | Company limited by guarantee | Live |
| CITY OPERA LIMITED | Company limited by guarantee | Live |
| HONG KONG DREAM OPERA CO., LIMITED | | Live |
| OPERA OF THE NATIONS CO., LIMITED | Private company limited by shares | Live |
| Cantonese Opera Culture (International) Communication Association Limited | | Live |
| OPERA HOTEL CONSULTANT LIMITED | Private company limited by shares | Live |
| OPERA CONSULTING LIMITED | Private company limited by shares | Dissolved |
| OPERA FGF CONSULTING & TRADING LIMITED | Private company limited by shares | Dissolved |