| HydroSeal Limited | Private company limited by shares | Dissolved |
| HYDROSEAL CANADA LIMITED | Private company limited by shares | Live |
| HYDROSEAL CANADA PIPING SYSTEMS CO., LIMITED | Private company limited by shares | Live |
| HYDROSEAL CANADA PRODUCT MANAGEMENT LIMITED | Private company limited by shares | Dissolved |
| HYDROSEAL CORPORATION LIMITED | Private company limited by shares | Live |
| HYDROSOFT LIMITED | Private company limited by shares | Live |
| Hydrosonic Limited | Private company limited by shares | Live |
| HYDROSPA LIMITED | Private company limited by shares | Live |
| HydroSpotless Company Limited | Private company limited by shares | Live |
| HYDROSTAR HK LIMITED | Private company limited by shares | Live |
| USA HYDRO-STOP (CHINA) LIMITED | Private company limited by shares | Live |
| HYDROSUN CANADA LIMITED | Private company limited by shares | Live |
| HYDROTEC CO., LIMITED | Private company limited by shares | Dissolved |
| HYDROTEC HYDRAULIC TECHNOLOGY LIMITED | Private company limited by shares | Dissolved |
| HYDROTECH R & D LIMITED | Private company limited by shares | Dissolved |
| HYDRO-TECH LIMITED | Private company limited by shares | Live |
| HYDROTEK COMPANY LIMITED | Private company limited by shares | Dissolved |
| JUST WALK ANIMAL HYDROTHERAPY COMPANY LIMITED | Private company limited by shares | Live |
| Asia Pacific Hydrotherapy Rehabilitation Research Center Limited | Private company limited by shares | Live |
| HYDROHEALTH COLON HYDROTHERAPY LIMITED | Private company limited by shares | Live |
| WATER-CUBE INT'L HYDROTHERAPY PLAN MANAGE GROUP (HK) LIMITED | Private company limited by shares | Dissolved |
| Hong Kong Hydro-therapy Tutor Association Limited | Company limited by guarantee | Live |
| INT'L SWIMMING POOL HYDROTHERAPY GROUP LIMITED | Private company limited by shares | Dissolved |
| OASIS HYDROTHERAPY SYSTEMS LIMITED | Private company limited by shares | Live |
| Germany Slow Old Hydrotherapy Electrical Co., Limited | | Live |
| HydroTide Company Limited | Private company limited by shares | Live |
| Hydroverse Company Limited | | Live |
| HYDROVICTOR HONG KONG LIMITED | Private company limited by shares | Dissolved |
| HydroWealth Trading Limited | | Live |
| HYDROWEAR ASIA LIMITED | Private company limited by shares | Live |
| Hydrowise Limited | Private company limited by shares | Live |
| Hydroworks Limited | Private company limited by shares | Live |
| HydroWorld LIMITED | Private company limited by shares | Live |
| HydroX Group Limited | | Live |
| HYDROX (HK) LIMITED | Private company limited by shares | Dissolved |
| HYDROX TECHNOLOGY LIMITED | Private company limited by shares | Dissolved |
| HYDROXY LIMITED | Private company limited by shares | Live |
| HYDRUS HK LIMITED | | Live |
| Hydsoft Co., Limited | Private company limited by shares | Live |
| Hydsoft International Limited | | Live |
| HYDTRADE CO., LIMITED | Private company limited by shares | Live |
| HYDY Operations (HK) Limited | | Live |
| HYE. LIMITED | Private company limited by shares | Live |
| H.Y.E. ENTERPRISE LIMITED | Private company limited by shares | Dissolved |
| HYEFF LIMITED | | Live |
| HYEIN CO., LIMITED | Private company limited by shares | Live |
| HYEIN TRADING LIMITED | Private company limited by shares | Live |
| HYELE LIMITED | | Live |
| Hyen Cyber Limited | Private company limited by shares | Live |
| hyena films Limited | Private company limited by shares | Live |
| HYENA GLOBAL COMPANY LIMITED | Private company limited by shares | Live |
| Hyence Limited | | Live |
| H&Y(Engineering)Headhunter Limited | Private company limited by shares | Live |
| HYERST SPORTS CO., LIMITED | Private company limited by shares | Live |
| HYES LIMITED | Private company limited by shares | Live |
| HYETTA LIMITED | Private company limited by shares | Dissolved |
| HYFAT TRADING LIMITED | Private company limited by shares | Dissolved |
| HYFATRON ELECTRONIC COMPANY LIMITED | Private company limited by shares | Live |
| HYFEEL TECHNOLOGY LIMITED | Private company limited by shares | Live |
| Hyflux Utility WWT (BC) Limited | Private company limited by shares | Live |
| Hyflux Utility WT (GCL) Limited | Private company limited by shares | Live |
| Hyflux Utility WWT (GY) Limited | Private company limited by shares | Live |
| Hyflux Utility WTP (GY) Limited | Private company limited by shares | Live |
| Hyflux Utility (HLD) Limited | Private company limited by shares | Live |
| HYFLUX LIGHTING (HONG KONG) LIMITED | Private company limited by shares | Live |
| Hyflux Utility (LP) Limited | Private company limited by shares | Live |
| Hyflux Utility WT (LY) Limited | Private company limited by shares | Live |
| Hyflux Utility WT (MG) Limited | Private company limited by shares | Live |
| Hyflux Utility WWT (MG) Limited | Private company limited by shares | Live |
| Hyflux Utility (TJ) Limited | Private company limited by shares | Live |
| Hyflux Utility (TY) Limited | Private company limited by shares | Live |
| Hyflux Utility WWTP (GY) Limited | Private company limited by shares | Live |
| Hyflux Utility (WX) Limited | Private company limited by shares | Live |
| Hyflux Utility (YK) Limited | Private company limited by shares | Live |
| Hyflux Utility WWT (YKG) Limited | Private company limited by shares | Live |
| Hyflux Utility WT (YKG) Limited | Private company limited by shares | Live |
| Hyflux Utility WWT (YL) Limited | Private company limited by shares | Live |
| Hyflux Utility (YL) Limited | Private company limited by shares | Live |
| Hyflux Utility WT (YL) Limited | Private company limited by shares | Live |
| HYFORM LIMITED | Private company limited by shares | Dissolved |
| HYfortune International Trade Limited | Private company limited by shares | Live |
| QUANZHOU HYFS INDUSTRY AND TRADE CO., LIMITED | Private company limited by shares | Live |
| HYFUNG TRADING COMPANY (H.K.) LIMITED | Private company limited by shares | Dissolved |
| HYFUS INTERNATIONAL LIMITED | Private company limited by shares | Live |
| HYGAIN INDUSTRIAL CO., LIMITED | Private company limited by shares | Live |
| HYGEA COMPANY LIMITED | Private company limited by shares | Live |
| Hygeatec Company Limited | Private company limited by shares | Live |
| Hygeatec HK Limited | | Live |
| HYGEE LIMITED | Private company limited by shares | Live |
| HK Hygee. Limited | | Live |
| HYGEIA LIMITED | Private company limited by shares | Dissolved |
| HYGEIA LIMITED | | Live |
| Hygeia Bio-technology Company Limited | Private company limited by shares | Live |
| HYGEIA ELECTRONIC LIMITED | Private company limited by shares | Live |
| HYGEIA ELECTRONICS CO., LIMITED | Private company limited by shares | Live |
| HYGEIA FASHION COMPANY LIMITED | Private company limited by shares | Live |
| Hygeia sally United Health Group.hk Limited | Private company limited by shares | Live |
| Hygeia Healthcare(HK) Co., Limited | Private company limited by shares | Live |
| HYGEIA LAND (HONG KONG) TRADING LIMITED | Private company limited by shares | Dissolved |
| HONG KONG HYGEIA PHARMACEUTICAL LIMITED | Private company limited by shares | Live |