| Oilklenze Holding Company Limited | Private company limited by shares | Live |
| OILLAND (HONG KONG) TECHNOLOGY LIMITED | Private company limited by shares | Live |
| OILLAND GROUP (HONGKONG) TECHNOLOGY CO., LIMITED | Private company limited by shares | Live |
| OILLAND ENERGY SERVICES LIMITED | Private company limited by shares | Dissolved |
| Jiashan Wuzhou Oilless Bearing Co., Limited | Private company limited by shares | Live |
| OILLIECHIP LIMITED | Private company limited by shares | Live |
| OILLILY LIMITED | Private company limited by shares | Live |
| OILMAN GROUP LIMITED | Private company limited by shares | Live |
| OILMATE ENERGY TECHNOLOGY LIMITED | Private company limited by shares | Live |
| OILMEAL TRADE LIMITED | Private company limited by shares | Live |
| OILNET LIMITED | Private company limited by shares | Dissolved |
| OILO LIMITED | Private company limited by shares | Dissolved |
| OILONG INT'L GROUP (HK) LIMITED | Private company limited by shares | Dissolved |
| GERMANY OIL-P INT'L OIL GROUP LIMITED | Private company limited by shares | Live |
| OILPAMPSERVICE LIMITED | Private company limited by shares | Live |
| OILPATCH SALES LIMITED | Private company limited by shares | Dissolved |
| 96 OILS CO. LIMITED | Private company limited by shares | Dissolved |
| HOI WAI OILS LIMITED | Private company limited by shares | Dissolved |
| ASIAN ESSENTIAL OILS LIMITED | Private company limited by shares | Live |
| Friola Edible Oils Limited | Private company limited by shares | Live |
| SOUTH PACIFIC ESSENTIAL OILS LIMITED | Private company limited by shares | Dissolved |
| SUMMERWIND OILS AND GRAINS TRADING COMPANY LIMITED | Private company limited by shares | Dissolved |
| Sunshine Oilsands (Hong Kong) Limited | Private company limited by shares | Live |
| MERCOM OILSANDS LIMITED | Private company limited by shares | Dissolved |
| OILSO CO., LIMITED | Private company limited by shares | Live |
| OILSTONE LIMITED | Private company limited by shares | Dissolved |
| OILSTORE (ASIA) LIMITED | Private company limited by shares | Live |
| OILTECH USA LIMITED | Private company limited by shares | Live |
| DALLAS OIL-TEX COMPANY LIMITED | Private company limited by shares | Dissolved |
| Oiltique International Limited | Private company limited by shares | Live |
| OILTON LIMITED | Private company limited by shares | Dissolved |
| OILTON INDUSTRIAL LIMITED | Private company limited by shares | Dissolved |
| DRAGON OILTOOLS LIMITED | Private company limited by shares | Live |
| OILTOWN INVESTMENTS LIMITED | Private company limited by shares | Live |
| OilTrans Limited | Private company limited by shares | Live |
| OILTREK LIMITED | Private company limited by shares | Live |
| OILY GEM COMPANY LIMITED | Private company limited by shares | Dissolved |
| Oily Family Limited -The- | Private company limited by shares | Live |
| OILY INVESTMENT LIMITED | Private company limited by shares | Live |
| Oilyland Asia HK Limited | Private company limited by shares | Live |
| OILYON COMPANY LIMITED | Private company limited by shares | Dissolved |
| OIMAX (CHINA) LIMITED | Private company limited by shares | Live |
| U.S.A OIMEISC KEI KIT FATING INDUSTRIAL COMPANY LIMITED | Private company limited by shares | Dissolved |
| OIMIS CO., LIMITED | Private company limited by shares | Live |
| HK OIMM BEAUTY INDUSTRY (HOLDING) CO., LIMITED | Private company limited by shares | Live |
| OIMSOURCE LIMITED | Private company limited by shares | Live |
| O-Infinity Hong Kong Company Limited | Private company limited by shares | Live |
| OINK OINK COMMUNICATIONS LIMITED | Private company limited by shares | Live |
| OINK SQUARE LIMITED | Private company limited by shares | Live |
| Ointek HK Limited | Private company limited by shares | Live |
| PING ON OINTMENT COMPANY LIMITED | Private company limited by shares | Live |
| SWISS OIODIN LIFE SCIENCE TECHNOLOGY (INTERNATIONAL) LIMITED | Private company limited by shares | Live |
| OIOI LIMITED | Private company limited by shares | Live |
| OIOI HOLDING LIMITED | | Live |
| OION LIMITED | Private company limited by shares | Live |
| OIOO Hong Kong Limited | Private company limited by shares | Dissolved |
| OIOOIO CO., LIMITED | Private company limited by shares | Live |
| OIPA COMPANY LIMITED | Private company limited by shares | Dissolved |
| OIRO COMPANY LIMITED | Private company limited by shares | Live |
| Oirontech Limited | Private company limited by shares | Live |
| Oiru Trading Company Limited | | Live |
| Oisac Holding Limited | Private company limited by shares | Live |
| Oisaka Co., Limited | Private company limited by shares | Live |
| ESSAN & OISHI HK LIMITED | | Live |
| OISHI TABEMONO LIMITED | Private company limited by shares | Live |
| OISHII LIMITED | Private company limited by shares | Dissolved |
| Oishii Limited | Private company limited by shares | Dissolved |
| Oishii Don Limited | Private company limited by shares | Live |
| Oishii Jewelry Limited | Private company limited by shares | Dissolved |
| Oi-Shi-Sushi Limited | Private company limited by shares | Live |
| Oi-Shi-Sushi Group Limited | Private company limited by shares | Live |
| Oi-Shi-Sushi (Tai Po) Limited | Private company limited by shares | Live |
| Oisix Hong Kong Company Limited | Private company limited by shares | Live |
| Oiss Brand Limited | | Live |
| ITALY OISTON (H.K.) GROUP LIMITED | Private company limited by shares | Dissolved |
| Oisum Insurance Co., Limited | Private company limited by shares | Dissolved |
| OITA COMPANY LIMITED | Private company limited by shares | Dissolved |
| Oitenta por Oito Limited | Private company limited by shares | Live |
| O.I.T.M. LIMITED | Private company limited by shares | Dissolved |
| OITT HOLDINGS CO., LIMITED | Private company limited by shares | Live |
| OIVO BEAUTY LIMITED | Private company limited by shares | Live |
| OIWA LIMITED | Company limited by guarantee | Live |
| OIWANT DEVELOP CO., LIMITED | Private company limited by shares | Live |
| Oiwe Health Pharmaceutical (HK) Limited | | Live |
| OIWTECH TECHNOLOGY LIMITED | Private company limited by shares | Live |
| USA OIWU MEDICINE GROUP (H.K) COMPANY LIMITED | Private company limited by shares | Dissolved |
| OIYN LIMITED | Private company limited by shares | Live |
| Oizaki Pharmaceutical Co., Limited | | Live |
| Oiziz Limited | | Live |
| OIZO INTERNATIONAL (H.K) COMPANY LIMITED | Private company limited by shares | Live |