| Wildmill Accident Repair Centre (Taunton) Ltd | Wholesale & retail | 2024 |
| Wildmill Group Ltd | Financial services | 2024 |
| Wildsearchpartners Limited | Administrative & support | 2026 |
| Will & Probate Services Limited | Professional & scientific | 1992 |
| William Bird (Properties) Limited | Construction | 1995 |
| William Bird Properties Holdings Limited | Professional & scientific | 1995 |
| Willmass Electrical Limited | Construction | 2023 |
| Willow Appliances Limited | Manufacturing | 2019 |
| Wilson Heyes Associates Limited | Professional & scientific | 1987 |
| Wilson Logistics Limited | Transport & logistics | 2013 |
| Windmill Equestrian Ltd | Agriculture & fishing | 2016 |
| Windmill Farm Equestrian Ltd | Agriculture & fishing | 2016 |
| Window and Door Surgeon Ltd | Construction | 2026 |
| Winner & Krieger Ltd | Extraterritorial | 2012 |
| Winners Bingo Clubs Limited | Financial services | 2005 |
| Winners Estates Limited | Real estate | 2006 |
| Winterton Auctioneers Limited | Other services | 2021 |
| WIP Bar Ltd | Hospitality | 2019 |
| Wivenhoe Gardens Management Company Limited | Households | 2025 |
| WJP Holdings 2025 Limited | Financial services | 2025 |
| WJR Property Holdings Ltd | Real estate | 2024 |
| WKM Ventures Limited | Other services | 2024 |
| WMH 220 Ltd | Professional & scientific | 2003 |
| Wodnorths Ltd | Transport & logistics | 2019 |
| Wojtek Project Management Limited | Construction | 2020 |
| Wolf Workwear Limited | Wholesale & retail | 2025 |
| Wolfsbane HMS Ltd | Wholesale & retail | 2018 |
| Wollaston Properties Limited | Construction | 1957 |
| Woodhouse Farm and Garden CIC | Other services | 2013 |
| Woodland Gates & Garage Doors Ltd | Manufacturing | 2019 |
| Woodley House Limited | Health & social care | 1989 |
| Woodridge House (Weeford) Management Company Limited | Real estate | 2013 |
| Woodstone Systems Ltd | Professional & scientific | 2014 |
| Woodview Motors Limited | Wholesale & retail | 2006 |
| Woody Developments Ltd | Professional & scientific | 2024 |
| Woodys Driver Solutions Limited | Transport & logistics | 2014 |
| Woof and Tumble DDC Limited | Other services | 2025 |
| Woolstitch Ltd | Agriculture & fishing | 2024 |
| Workhaus Limited | Real estate | 2020 |
| Workr Automation Limited | Information & communication | 2026 |
| Workr Engine Limited | Information & communication | 2026 |
| Workr Holdings Limited | Financial services | 2026 |
| Worksco Ltd | Construction | 2019 |
| Workwear & Safety Supplies Limited | Administrative & support | 2019 |
| Workwear UK Connections Limited | Wholesale & retail | 2015 |
| Worth Matravers Ltd | Administrative & support | 2022 |
| Wouldham Ltd | Administrative & support | 2022 |
| WOW International Ltd | Transport & logistics | 2026 |
| WOW Logistics Ltd | Transport & logistics | 2020 |
| WP Watts Ltd | Other services | 2026 |
| WPF Enterprises Ltd | Extraterritorial | 2025 |
| Wrekin Holdings Limited | Professional & scientific | 2003 |
| Wrekin Products Limited | Manufacturing | 1991 |
| Wright People HR Ltd | Professional & scientific | 2018 |
| WS13 Store Limited | Wholesale & retail | 2026 |
| WS14 Animal Services Limited | Professional & scientific | 2025 |
| Wychwood Ventures Limited | Hospitality | 2026 |
| Wyndborne Properties Ltd | Real estate | 2021 |
| Wynter Sign Services and Branding Ltd | Manufacturing | 2022 |
| Wyvern Global Ltd | Information & communication | 2024 |
| X B Carpentry & Building Ltd | Construction | 2019 |
| X-Design (UK) Limited | Wholesale & retail | 2008 |
| X-Traweld Holdings Ltd | Financial services | 2024 |
| X-Traweld Services Ltd | Manufacturing | 2003 |
| X2 Electrical Limited | Construction | 2024 |
| X30 Group Limited | Information & communication | 2015 |
| XAF Limited | Wholesale & retail | 2009 |
| XB Developments Limited | Construction | 2024 |
| XB Group Holdings Limited | Financial services | 2025 |
| XB Real Estate Limited | Real estate | 2022 |
| Xilla Limited | Arts & recreation | 2019 |
| XJ Design Limited | Information & communication | 2013 |
| XK Farrow Ltd | Administrative & support | 2022 |
| Xrella Ltd | Information & communication | 2026 |
| Xternal Design Solutions Limited | Professional & scientific | 2012 |
| Xternal Properties Limited | Real estate | 2022 |
| Xternal Solutions Limited | Other services | 2003 |
| Yamyam Productions Limited | Information & communication | 2023 |
| Yanley Consultants Limited | Professional & scientific | 2016 |
| Yardley Talent Consulting Ltd | Administrative & support | 2020 |
| Yarnell Consultancy Limited | Professional & scientific | 2005 |
| Yaxley Farm Limited | Agriculture & fishing | 1990 |
| Yeether Limited | Information & communication | 2024 |
| Yellow Box Recruitment Ltd | Administrative & support | 2023 |
| Yellow Saturn Limited | Professional & scientific | 2020 |
| Yeomans Developments Ltd | Administrative & support | 2024 |
| YHJ Consulting Ltd | Other services | 2024 |
| Yoley Limited | Information & communication | 2022 |
| Youonit Limited | Information & communication | 2025 |
| Your Future : Mortgage & Protection Ltd | Financial services | 2021 |
| Your Local Family Solicitors Limited | Professional & scientific | 2016 |
| Your Local Roofing Experts Ltd | Construction | 2026 |
| Your Mamahood Ltd | Information & communication | 2025 |
| Youtech Solutions Limited | Information & communication | 2020 |
| Yoxaille Ltd | Construction | 2021 |
| Yummyumptious Limited | Extraterritorial | 2017 |
| Ywpa Limited | Arts & recreation | 2019 |
| Z3 Digital Limited | Administrative & support | 2013 |
| Zahoor Investments Ltd | Real estate | 2021 |
| Zaytoun Spice Limited | Hospitality | 2018 |