| Wrenbridge (Norfolk) Limited | Construction | 1997 |
| Wrenbridge (WH Way) Limited | Real estate | 2012 |
| Wrenbridge (Woodhouse) Limited | Real estate | 2012 |
| Wrenbridge Developments Ltd | Real estate | 2013 |
| Wrenbridge Limited | Real estate | 2013 |
| Wrenfield Limited | Professional & scientific | 1982 |
| Wrenmoor Consulting Limited | Professional & scientific | 2017 |
| Wright Decorating and Building Services Ltd | Construction | 2013 |
| Wright Design Holdings Limited | Professional & scientific | 2000 |
| Wright Party Wall Surveyors (Cambridge) Ltd | Construction | 2022 |
| Wright-Way Cleaning and Maintenance Services Limited | Administrative & support | 2008 |
| Wrights Cafe Limited | Hospitality | 2019 |
| Wrights Marine Services Ltd | Manufacturing | 2025 |
| Wrightson Corporate Management Limited | Information & communication | 2009 |
| Writemedical Ltd | Professional & scientific | 2013 |
| Writeology Ltd | Administrative & support | 2021 |
| Wrona Engineering Ltd | Manufacturing | 2025 |
| WS Plumbing and Heating Ltd | Construction | 2012 |
| WT Industry Co., Ltd | Extraterritorial | 2023 |
| Wt's Sports Bar Limited | Administrative & support | 2014 |
| Wtbcn Trading Limited | Wholesale & retail | 2017 |
| WTG - UK Consultancy Limited | Education | 2015 |
| Wuka Ltd | Wholesale & retail | 2017 |
| Wuxi Hongyuan Decoration Material Industry Co., Ltd | Manufacturing | 2014 |
| WWG Group Ltd | Financial services | 2026 |
| Wwj&Z Ltd | Information & communication | 2025 |
| WX Enterprises Ltd | Professional & scientific | 2025 |
| WX2 Motorsport Ltd | Wholesale & retail | 2023 |
| WXK UK Import and Export Co., Ltd | Manufacturing | 2025 |
| WXL International Limited | Wholesale & retail | 2026 |
| Wyatt Farm Ltd | Real estate | 2021 |
| Wybract Limited | Financial services | 2014 |
| Wychfield Associates Limited | Professional & scientific | 2018 |
| Wyck Hill Management Company Limited | Households | 2024 |
| Wyck Hill Property LLP | | 2021 |
| Wyld Networks Limited | Information & communication | 2016 |
| Wylde Sky Brewing Ltd | Manufacturing | 2017 |
| Wyse Enterprises Ltd | Education | 2025 |
| Wysing Arts Charity | Arts & recreation | 1994 |
| Wyton Residents Company Limited | Households | 2001 |
| X-Arc Ltd | Wholesale & retail | 2025 |
| X-Biocell Ltd | Professional & scientific | 2010 |
| X-Felt New Material Technology Co., Ltd. | Manufacturing | 2025 |
| X-Sentience Limited | Information & communication | 2020 |
| X. Metas. Capital Ltd | Wholesale & retail | 2021 |
| Xaar 3D Holdings Limited | Financial services | 2018 |
| Xaar Digital Limited | Financial services | 1998 |
| Xaar PLC | Manufacturing | 1997 |
| Xaar Technology Limited | Professional & scientific | 1990 |
| Xaar Trustee Limited | Professional & scientific | 1995 |
| Xaarjet (Overseas) Limited | Other services | 2001 |
| Xaarjet Limited | Manufacturing | 1997 |
| Xairos UK Limited | Manufacturing | 2023 |
| Xampla Ltd | Professional & scientific | 2018 |
| Xanadome Limited | Construction | 2000 |
| Xania Limited | Real estate | 2024 |
| Xanle Trade Ltd | Wholesale & retail | 2024 |
| Xanthos Limited | Information & communication | 2002 |
| Xantipus Ltd | Manufacturing | 2024 |
| XAP Therapeutics Limited | Financial services | 2017 |
| Xaviandrew Ltd | Wholesale & retail | 2024 |
| Xbit Ltd | Information & communication | 2023 |
| Xcalimed Sciences Ltd | Professional & scientific | 2023 |
| Xchill World Limited | Manufacturing | 2025 |
| Xclaro Ltd | Information & communication | 2016 |
| Xeal Tech Ltd | Wholesale & retail | 2023 |
| XEN Quantum Ltd | Professional & scientific | 2025 |
| Xendata Limited | Information & communication | 2001 |
| Xenia's Crafts Ltd | Manufacturing | 2024 |
| Xenity Ltd | Professional & scientific | 2011 |
| Xenonwave Ltd | Professional & scientific | 2003 |
| Xenss Technology Limited | Professional & scientific | 2024 |
| Xerani Ltd | Manufacturing | 2025 |
| Xero Heroes Ltd | Professional & scientific | 2017 |
| Xftl Ltd | Information & communication | 2026 |
| XHM International Limited | Wholesale & retail | 2026 |
| Xiamen Pike Industrial Co., Limited | Extraterritorial | 2013 |
| Xian GE Import and Export Co., Limited | Wholesale & retail | 2023 |
| Xian Noodle Limited | Hospitality | 2021 |
| Xiaojia Limited | Wholesale & retail | 2025 |
| Xikai Ltd | Wholesale & retail | 2023 |
| Xilinx Limited | Administrative & support | 1987 |
| Xilinx Technology Ltd | Information & communication | 2002 |
| XIN Dong WEI Marine Service Limited | Wholesale & retail | 2023 |
| XIN Ping Technology Trade Co., Ltd | Wholesale & retail | 2026 |
| Xinbo Star Co., Ltd | Wholesale & retail | 2017 |
| Xincheng International Trading Co., Ltd | Transport & logistics | 2020 |
| Xinde International Trade Co., Limited | Wholesale & retail | 2023 |
| Xinfenghai Shipping Co., Ltd | Manufacturing | 2019 |
| Xinfu Panda Ltd | Hospitality | 2025 |
| Xingchen Ltd | Administrative & support | 2025 |
| Xingchen Network Limited | Information & communication | 2026 |
| Xingdechang International Trading Co., Ltd | Wholesale & retail | 2023 |
| Xinglin Technology Ltd | Information & communication | 2025 |
| Xingyang Shipping Co., Ltd | Wholesale & retail | 2024 |
| Xinhe Science and Technology Co., Limited | Extraterritorial | 2014 |
| Xinhong Simulation Model Co., Ltd | Wholesale & retail | 2023 |
| Xinjiang Mingsheng International Trade Co., Ltd | Manufacturing | 2025 |
| Xinjiang Silk Road Automobile Import and Export Trade Co., Ltd. | Manufacturing | 2025 |
| Xinjiang Zeji International Trade Co., Ltd | Manufacturing | 2025 |