| Worx Electrical Ltd | Construction | 2018 |
| Worx Innovation Limited | Construction | 2018 |
| Worx Properties Limited | Real estate | 2018 |
| Woven Group of Companies Limited | Wholesale & retail | 2023 |
| WOW Aromatherapy Ltd | Wholesale & retail | 2024 |
| Wowpos Ltd | Information & communication | 2015 |
| Wowtel Ltd | Information & communication | 2016 |
| WP Investments Limited | Real estate | 2002 |
| WPE2 Ltd | Hospitality | 2023 |
| Wrapp Northampton Ltd | Construction | 2022 |
| WRC Properties Limited | Real estate | 2019 |
| Wren Assets Limited | Real estate | 2022 |
| Wreroof.Com Limited | Construction | 2022 |
| Wright Consulting (Biosciences) Limited | Professional & scientific | 2011 |
| Wright OFF Road Limited | Manufacturing | 2010 |
| Wright People Ltd | Other services | 2016 |
| Wright Property Development Limited | Construction | 2014 |
| Wright's Commercials Limited | Wholesale & retail | 2016 |
| Wright's Hire Limited | Transport & logistics | 2016 |
| Wright's Storage Limited | Administrative & support | 2016 |
| Writing Solutions PVT Ltd | Wholesale & retail | 2021 |
| WRJ Transport Ltd | Transport & logistics | 2023 |
| Wroxham Accounting Services Limited | Professional & scientific | 2019 |
| WS & E Limited | Construction | 2025 |
| WS Roofing Ltd | Construction | 2026 |
| WSG Capital Ltd | Real estate | 2025 |
| WSL Industries Ltd | Wholesale & retail | 2005 |
| WSV Holdings Limited | Professional & scientific | 2007 |
| WT Stars Builders Ltd | Construction | 2022 |
| Wtec Limited | Information & communication | 2022 |
| WTH Property Development Limited | Real estate | 2022 |
| WVJ Investment Ltd | Construction | 2020 |
| Wvsourcing Ltd | Arts & recreation | 2020 |
| Ww.Mh Limited | Construction | 2017 |
| WWS OIL & GAS Consultancy UK Ltd | Mining & quarrying | 2017 |
| Www.Dimplesceniza.Com Ltd | Wholesale & retail | 2024 |
| Wxuk Ltd | Professional & scientific | 2024 |
| Wyatt DPB Limited | Professional & scientific | 2007 |
| Wyatt Park Mansions Flats Management Company (Lambeth) Limited | Households | 1984 |
| Wycombe Feather Group Limited | Professional & scientific | 1987 |
| Wycombe Trading Limited | Financial services | 2014 |
| Wykes Estates Limited | Real estate | 2025 |
| Wylie Adair Limited | Professional & scientific | 2007 |
| Wymondley 10 Renewables Holdco Ltd | Professional & scientific | 2023 |
| Wymondley 10 Renewables Ltd | Administrative & support | 2023 |
| X INT Ltd | Professional & scientific | 2025 |
| X Tech Limited | Professional & scientific | 2003 |
| X-Performance Development Limited | Professional & scientific | 2009 |
| X.D.Steelfixing Limited | Construction | 2021 |
| X3 Electrical Ltd | Construction | 2025 |
| X3 Ltd | Wholesale & retail | 2019 |
| Xactima Holdings Limited | Professional & scientific | 2017 |
| Xactima Limited | Professional & scientific | 2013 |
| Xanadu Care Developments Limited | Financial services | 2025 |
| Xanadu Care Group Limited | Administrative & support | 2010 |
| Xanadu Properties (Spain) Limited | Extraterritorial | 2015 |
| Xanadu Towcester Limited | Real estate | 2021 |
| Xandy Productions Limited | Information & communication | 2008 |
| Xanthous 10 Limited | Extraterritorial | 1966 |
| Xanthous 11 Limited | Extraterritorial | 1999 |
| Xanthous 12 Limited | Extraterritorial | 1998 |
| Xanthous 14 Limited | Extraterritorial | 2002 |
| Xanthous 2 Limited | Professional & scientific | 1994 |
| Xanthous 5 Limited | Extraterritorial | 1986 |
| Xanthous 6 Limited | Professional & scientific | 1983 |
| Xanthous 7 Limited | Extraterritorial | 2001 |
| Xanthous 8 Limited | Extraterritorial | 1985 |
| Xanthous 9 Limited | Extraterritorial | 1987 |
| Xavia Medical (UK) Limited | Wholesale & retail | 2023 |
| XB Film Services Limited | Information & communication | 2022 |
| XBW Engineering Limited | Professional & scientific | 2022 |
| Xcam Limited | Manufacturing | 1995 |
| Xchange Communications Limited | Financial services | 2003 |
| XD Taxis Limited | Transport & logistics | 2021 |
| XEC Trvl Ltd | Transport & logistics | 2024 |
| Xelp Ltd | Construction | 2024 |
| XEN Trans Ltd | Transport & logistics | 2013 |
| Xenia Holdings Limited | Hospitality | 2019 |
| Xennox Solutions Limited | Information & communication | 2009 |
| Xflex Limited | Information & communication | 2000 |
| Xhasa Limited | Hospitality | 2009 |
| Xhiko Brickworks Ltd | Construction | 2021 |
| Xiaojdajqda Limited | Construction | 2026 |
| Xicom Systems Limited | Professional & scientific | 1994 |
| XL Markets Ltd | Manufacturing | 2019 |
| XM Technologies Limited | Professional & scientific | 2002 |
| XO Baby Limited | Wholesale & retail | 2020 |
| XP Medical Ltd | Extraterritorial | 2020 |
| XP Recruitment Limited | Administrative & support | 2003 |
| Xpbl Limited | Wholesale & retail | 2026 |
| Xpertees-Uk Ltd | Wholesale & retail | 2013 |
| Xperts Professional Cleaning Services Ltd | Administrative & support | 2025 |
| Xpin Management Limited | Hospitality | 2025 |
| Xplor Off-Grid Ltd | Manufacturing | 2025 |
| XPO Bulk UK Limited | Transport & logistics | 1994 |
| XPO Global Forwarding UK Limited | Transport & logistics | 1981 |
| XPO Holdings UK and Ireland Limited | Professional & scientific | 1993 |
| XPO Holdings UK I Limited | Financial services | 2018 |
| XPO Holdings UK II Limited | Financial services | 2018 |
| XPO Investment UK Limited | Professional & scientific | 1930 |