| William Bell ( Motors ) Ltd | Wholesale & retail | 2015 |
| William Bell Limited | Wholesale & retail | 2013 |
| William Construct Limited | Manufacturing | 2026 |
| Williams Installations Limited | Construction | 2010 |
| Willow Construction Limited | Construction | 2021 |
| Willow Rise Ltd | Real estate | 2025 |
| Willow Tree Education Limited | Education | 2006 |
| Wilson Douglas Limited | Administrative & support | 2009 |
| Windoor Solutions Ltd | Construction | 2026 |
| Window Cleaning LDN Limited | Administrative & support | 2026 |
| Windscreen Care Limited | Wholesale & retail | 2020 |
| Windsor View Limited | Extraterritorial | 2016 |
| Winerackd Limited | Wholesale & retail | 2014 |
| Winhope Limited | Financial services | 2005 |
| Winhope Travel Limited | Administrative & support | 2025 |
| Winston Close Enterprises Limited | Administrative & support | 2007 |
| Wisley Properties Limited | Real estate | 2021 |
| Witts Furniture Ltd | Wholesale & retail | 2022 |
| Witworkx Ltd | Information & communication | 2021 |
| Wokingham Drains Ltd | Extraterritorial | 2015 |
| Wolf Nation Ltd | Wholesale & retail | 2018 |
| Wolf of Wallstrip Limited | Construction | 2026 |
| Wolfhampcote Builders Limited | Construction | 2020 |
| Wollu Limited | Health & social care | 2018 |
| Wolsey SL Investments Limited | Professional & scientific | 2017 |
| Wolverhampton Prop Ltd | Real estate | 2025 |
| Women in Stem Ltd | Information & communication | 2023 |
| Wonderfin Ltd | Wholesale & retail | 2020 |
| Wonderinvestments Holding Ltd | Financial services | 2020 |
| Wong & LI (UK) Ltd | Real estate | 2013 |
| Wood Farm Close Residents Management Limited | Households | 2015 |
| Wood Lane Properties Limited | Real estate | 2015 |
| Wood Shed Farm Ltd | Transport & logistics | 2022 |
| Wood Wharf Kindergarten Limited | Education | 2021 |
| Woodcroft Residents Association (Stanmore) Limited | Households | 1968 |
| Woodfield Court Residential Management Limited | Real estate | 2015 |
| Woodfield House Properties Limited | Professional & scientific | 1972 |
| Woodford Court Residents Limited | Real estate | 2013 |
| Woodland Developers Ltd | Real estate | 2022 |
| Woodside Property Solutions (London) Limited | Real estate | 2022 |
| Woodside Property Solutions Limited | Real estate | 2019 |
| Woodstock OT Cyber Security Ltd | Information & communication | 2026 |
| Woolfe Properties Ltd | Real estate | 2009 |
| Words in Motion Ltd | Health & social care | 2025 |
| Workfones Limited | Information & communication | 2018 |
| Workham Hotels Limited | Administrative & support | 2023 |
| Workspend Limited | Professional & scientific | 2020 |
| Workwear World Limited | Wholesale & retail | 1993 |
| World Beaters Arts and Culture Limited | Education | 2005 |
| World FED Investments Limited | Real estate | 2021 |
| World Finance Investments Ltd | Financial services | 2023 |
| World Soldiers Limited | Wholesale & retail | 2010 |
| WOW Wellness Limited | Health & social care | 2017 |
| WPI Economics Limited | Professional & scientific | 2016 |
| WRA Associates Ltd | Professional & scientific | 2013 |
| Wrexham Acquisitions Limited | Administrative & support | 2024 |
| Wright Key Removals Ltd | Transport & logistics | 2021 |
| Wrsd Ltd | Administrative & support | 2012 |
| WSL Enterprise Ltd | Real estate | 2017 |
| WTF Technology Limited | Manufacturing | 2001 |
| Wykeham House Limited | Households | 2003 |
| Wylye Valley Gardening Ltd | Administrative & support | 2017 |
| Wynches Consulting Limited | Information & communication | 2012 |
| Wynell Ltd | Construction | 2024 |
| X Facilities Group Limited | Construction | 2024 |
| X Finance Ltd | Financial services | 2020 |
| X-Curve Systems Limited | Other services | 2019 |
| X4 CHK Ltd | Professional & scientific | 2024 |
| Xacuti Spice Limited | Hospitality | 2019 |
| Xcel Bespoke Limited | Administrative & support | 2018 |
| Xcel Concepts Limited | Administrative & support | 2016 |
| Xceptional Design Limited | Professional & scientific | 2013 |
| Xelution Ltd | Information & communication | 2015 |
| Xenia Developments Ltd | Real estate | 2016 |
| Ximtrade (UK) Ltd | Wholesale & retail | 2013 |
| XM Digital Limited | Information & communication | 2018 |
| Xpndr Ltd | Professional & scientific | 2023 |
| Xpronet Inc Limited | Mining & quarrying | 2015 |
| Xsml Limited | Real estate | 2017 |
| XX UN Ltd | Arts & recreation | 2025 |
| XXI Art Holdings Limited | Wholesale & retail | 2020 |
| Xylar Investments Ltd | Real estate | 2022 |
| Y2K Film Productions Limited | Professional & scientific | 1999 |
| YA2 Investments Limited | Other services | 2018 |
| Yadev Comms Ltd | Information & communication | 2025 |
| Yadev's Building Services Limited | Construction | 2016 |
| Yalla Beirut Lounge Limited | Hospitality | 2026 |
| Yamato Investments Limited | Real estate | 2016 |
| Yamuna Indian Limited | Hospitality | 2018 |
| Yanchoglo Limited | Professional & scientific | 2024 |
| Yangu Nyumba Ltd | Real estate | 2024 |
| Yansha Ltd | Financial services | 2026 |
| Yard Food Vibez Ltd | Hospitality | 2021 |
| Yarlington Court Management Company Limited | Households | 2000 |
| Yarlington Court RTM Company Limited | Households | 2019 |
| Yashee Limited | Information & communication | 2016 |
| Yashveee Limited | Wholesale & retail | 2021 |
| Yasmin Karimi Ltd | Wholesale & retail | 2014 |
| Yateley Manor School London Limited | Education | 2023 |
| Yazz Productions Limited | Information & communication | 2002 |