| Ultramarine Cie Limited | Private company limited by shares | Live |
| ULTRAMARINE INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| ULTRA-MARINE TRADING COMPANY LIMITED | Private company limited by shares | Live |
| ULTRAMARINE VIEW LIMITED | Private company limited by shares | Dissolved |
| ULTRA-MARK INTERNATIONAL LIMITED | Private company limited by shares | Dissolved |
| ULTRAMATCH TRADING LIMITED | Private company limited by shares | Dissolved |
| UltraMatrix Limited | | Live |
| ULTRAMAX LIMITED | Private company limited by shares | Dissolved |
| ULTRAMAX LIMITED | Private company limited by shares | Live |
| ULTRAMAX INVESTMENT LIMITED | Private company limited by shares | Live |
| ULTRAMEDIX HK LIMITED | Private company limited by shares | Dissolved |
| ULTRA-MERRY LIMITED | Private company limited by shares | Dissolved |
| ULTRAMET LIMITED | Private company limited by shares | Live |
| ULTRAMEX LIMITED | Private company limited by shares | Live |
| ULTRAMICRO ELECTRONICS (HK) CO., LIMITED | Private company limited by shares | Live |
| ULTRAMIROO LIMITED | Private company limited by shares | Live |
| ULTRAMODE CO. LIMITED | Private company limited by shares | Live |
| ULTRAMODERN LIMITED | Private company limited by shares | Dissolved |
| ULTRAMODERN INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| Ultramoist LIMITED | Private company limited by shares | Live |
| Ultramomentum Trading Limited | Private company limited by shares | Live |
| UltraMoney Limited | Private company limited by shares | Live |
| ULTRAMONIC LIMITED | Private company limited by shares | Dissolved |
| ULTRAMONT LIMITED | Private company limited by shares | Dissolved |
| ULTRAMONTANE LIMITED | Private company limited by shares | Dissolved |
| ULTRAMORE LIMITED | Private company limited by shares | Dissolved |
| ULTRANET C & C LIMITED | Private company limited by shares | Dissolved |
| ULTRANK LIMITED | Private company limited by shares | Dissolved |
| Ultrank Development Limited | Private company limited by shares | Live |
| ULTRANK INDUSTRIES LIMITED | Private company limited by shares | Dissolved |
| ULTRANS CARGO EXPRESS COMPANY LIMITED | Private company limited by shares | Dissolved |
| ULTRANS LOGISTIC LIMITED | Private company limited by shares | Dissolved |
| Ultra-Panels Limited | Private company limited by shares | Live |
| ULTRAPEI LIMITED | Private company limited by shares | Live |
| ULTRA-POSH ADVERTISING AND PRODUCTION COMPANY LIMITED | Private company limited by shares | Dissolved |
| ULTRAPOWER LIMITED | Private company limited by shares | Dissolved |
| Ultra-Power Technology Company Limited | Private company limited by shares | Dissolved |
| ULTRA-POWER TECHNOLOGY COMPANY LIMITED | Private company limited by shares | Dissolved |
| ULTRA-POWERFUL LIMITED | Private company limited by shares | Dissolved |
| ULTRAPPED LIMITED | Private company limited by shares | Live |
| ULTRA-PRETTY LIMITED | Private company limited by shares | Dissolved |
| Ultra-pro Beauty Limited | Private company limited by shares | Live |
| ULTRAPRO INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| Ultrapure Limited | | Live |
| UltraRadiant Systems Limited | Private company limited by shares | Live |
| Ultrareach Technology Co., Limited | | Live |
| ULTRA-REGAL LIMITED | Private company limited by shares | Dissolved |
| ULTRARICH LIMITED | Private company limited by shares | Dissolved |
| ULTRARICH CORPORATION LIMITED | Private company limited by shares | Live |
| ULTRARICH JEWELLERY MANUFACTURER LIMITED | Private company limited by shares | Live |
| ULTRART LIMITED | Private company limited by shares | Live |
| ULTRASAFE LIMITED | Private company limited by shares | Live |
| Ultrasaw Hong Kong Limited | Private company limited by shares | Dissolved |
| ULTRASCOPE DEVELOPMENT LIMITED | Private company limited by shares | Dissolved |
| ULTRASHAPE LIMITED | Private company limited by shares | Dissolved |
| ULTRA-SHARP LIMITED | Private company limited by shares | Dissolved |
| Ultrashield Limited | Private company limited by shares | Dissolved |
| ULTRASIA LIMITED | Private company limited by shares | Live |
| ULTRASKY LIMITED | Private company limited by shares | Dissolved |
| ULTRA-SMART LIMITED | Private company limited by shares | Dissolved |
| ULTRA-SMOOTH LIMITED | Private company limited by shares | Live |
| ULTRA-SOLID LIMITED | Private company limited by shares | Dissolved |
| Ultrasolis Limited | | Live |
| ULTRA-SONG KARAOKE SOUND SYSTEM (H.K.) LIMITED | Private company limited by shares | Live |
| ULTRASONIC COMPANY LIMITED | Private company limited by shares | Dissolved |
| ASIA ULTRASONIC LIMITED | Private company limited by shares | Live |
| DICKSON & ULTRASONIC PCB COMPANY LIMITED | Private company limited by shares | Dissolved |
| SANHO ULTRASONIC ENGINEERING LIMITED | Private company limited by shares | Live |
| ULTRASONIC INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| TUNG PO ULTRASONIC TECHNOLOGY COMPANY LIMITED | Private company limited by shares | Live |
| ULTRASONICA LIMITED | Private company limited by shares | Live |
| SJP Ultrasonics Limited | Private company limited by shares | Live |
| Ultrasonics Limited | | Live |
| BRANSON ULTRASONICS (ASIA PACIFIC) CO. LIMITED | Private company limited by shares | Live |
| Cheersonic Ultrasonics Co., Limited | Private company limited by shares | Live |
| ULTRASONICS ENGINEERING CO., LIMITED | Private company limited by shares | Live |
| Pyrocks Ultrasonics Company Limited | | Live |
| PZFlex Ultrasonics Limited | Private company limited by shares | Live |
| RINCO ULTRASONICS (HONG KONG) LIMITED | Private company limited by shares | Live |
| Hong Kong Endoscopic Ultrasonography Society Limited | Company limited by guarantee | Live |
| ULTRASOUND BOOTS (ASIA) LIMITED | Private company limited by shares | Live |
| ULTRASOUND BOOTS LIMITED | Private company limited by shares | Live |
| ULTRA-SOUND DIAGNOSTICS LIMITED | Private company limited by shares | Dissolved |
| Focused Ultrasound Hong Kong Foundation Limited | Company limited by guarantee | Live |
| ULTRASOUND INDUSTRIAL LIMITED | Private company limited by shares | Dissolved |
| ULTRASOUND INTERNATIONAL LIMITED | Private company limited by shares | Dissolved |
| Focused Ultrasound Medical Research Foundation Limited | Company limited by guarantee | Live |
| Focused Ultrasound Surgery Association Limited | Company limited by guarantee | Live |
| Ultrasound Technology Co., Limited | | Live |
| GENERAL ULTRASOUND TECHNOLOGY LIMITED | Private company limited by shares | Live |
| PACIFIC ULTRASOUND TECHNOLOGY LIMITED | Private company limited by shares | Dissolved |
| ULTRASOUND TRADING LIMITED | Private company limited by shares | Live |
| Ultrasound Wondering Inc Limited | Private company limited by shares | Live |
| ULTRASOURCE COMPANY LIMITED | Private company limited by shares | Live |
| Ultraspeed Networks HK Limited | Private company limited by shares | Live |
| ULTRASPEX LIMITED | Private company limited by shares | Dissolved |
| ULTRA-SPLENDID LIMITED | Private company limited by shares | Dissolved |
| ULTRASTABLE LIMITED | Private company limited by shares | Dissolved |
| ULTRASTAR LIMITED | Private company limited by shares | Dissolved |
| Ultrastar HQ Limited | | Live |