| Woodcut Screen Limited | Information & communication | 2023 |
| Woodford Northlands Limited | Households | 2019 |
| Woodhouse Uplyme Management Limited | Households | 2008 |
| Woodlands International IP Ltd | Professional & scientific | 2026 |
| Woodlands International Ltd | Administrative & support | 2018 |
| Woodlark Place Management Company Limited | Households | 2014 |
| Woodlark Way Management Limited | Households | 2021 |
| Woodlore Restoration & Build Ltd | Administrative & support | 2017 |
| Woodrow Horsfall Limited | Professional & scientific | 1995 |
| Woodward Nash Limited | Administrative & support | 2007 |
| Word to Dialogue Limited | Professional & scientific | 2012 |
| Wordjuice Ltd | Information & communication | 2008 |
| Working END Ltd | Information & communication | 2019 |
| World Options International Ltd | Professional & scientific | 2017 |
| World Renewable Energy Network Limited | Education | 1990 |
| World Services Link Ltd | Administrative & support | 2024 |
| Worldwide Shipping & Airfreight Limited | Transport & logistics | 2005 |
| Worplesdon Court Residents Company Limited | Households | 2005 |
| Worthwhile Works CIC | Education | 2024 |
| Worthy Financial Planning Ltd | Financial services | 2012 |
| Worthy Heating and Plumbing Services Limited | Construction | 2006 |
| Worthy Wealth Management Ltd | Financial services | 2014 |
| Woza Afrika Ltd | Wholesale & retail | 2026 |
| WPS24 Ltd | Professional & scientific | 2024 |
| WRC Nuns Road Limited | Arts & recreation | 1994 |
| WRF and Associates Ltd | Construction | 2025 |
| Wright Choice Homes Ltd | Construction | 2025 |
| Writing School Ltd | Information & communication | 2024 |
| WRM Property UK Limited | Real estate | 2025 |
| WT Tax Ltd | Professional & scientific | 2014 |
| WTC Developments Limited | Construction | 2021 |
| Wtspc Limited | Manufacturing | 2006 |
| Wyberton House Limited | Households | 1999 |
| Wychwood Place Management Company Limited | Households | 2021 |
| Wycliffe Investment Limited | Real estate | 1961 |
| Wydelta Limited | Professional & scientific | 2015 |
| Wyfold Court Estate Ltd | Households | 1998 |
| Wykeham House Management Company Limited | Households | 1977 |
| Wylde Bespoke Ltd | Manufacturing | 2025 |
| Wyndward Ltd | Construction | 2022 |
| Wynstan Limited | Real estate | 2017 |
| X Rate Capital Ltd | Financial services | 2024 |
| X-Rm Cloud Services Limited | Information & communication | 2026 |
| X-Rm Limited | Information & communication | 1993 |
| X3M.AI Ltd | Information & communication | 2025 |
| X80 Limited | Information & communication | 2017 |
| Xcare Capital Limited | Administrative & support | 2023 |
| Xcentric Events Limited | Arts & recreation | 2012 |
| Xillia Ltd | Information & communication | 2018 |
| Xperate Limited | Information & communication | 2021 |
| Xpert Heating Services Ltd | Construction | 2013 |
| Xtrashot Limited | Professional & scientific | 2012 |
| Xvertise Limited | Professional & scientific | 2014 |
| Xx-Combinator Limited | Professional & scientific | 2025 |
| Yacht Intelligence Limited | Information & communication | 2010 |
| Yagci Barbers Ltd | Other services | 2025 |
| Yashar Barbers Ltd | Other services | 2025 |
| Yaskai Limited | Construction | 2017 |
| YDC Ltd | Professional & scientific | 2024 |
| Yeatmans Enterprises of Poole Limited | Real estate | 1960 |
| Yellow Moon Yellow Moon Limited | Professional & scientific | 2004 |
| Yeomans Estates Properties Ltd | Real estate | 2026 |
| YES and NO Limited | Information & communication | 2018 |
| Yeti Wall Limited | Real estate | 2025 |
| YEW Hill Limited | Information & communication | 2016 |
| YKW Consultants Ltd | Professional & scientific | 2011 |
| Yoce Ltd | Professional & scientific | 2025 |
| Yougetme Limited | Information & communication | 2022 |
| Young and White Limited | Real estate | 1996 |
| Young and Younger Inns Ltd | Hospitality | 2017 |
| Young's Plumbing and Heating Limited | Construction | 2022 |
| Your Partner for Property Profit Ltd | Real estate | 2016 |
| Youseq Ltd | Professional & scientific | 2018 |
| Zackary Adler Productions Limited | Information & communication | 2018 |
| Zahrada Design Limited | Professional & scientific | 2024 |
| Zala Property Ltd | Real estate | 2022 |
| Zamberetta Ltd | Information & communication | 2024 |
| Zaza Beauty Ltd | Other services | 2024 |
| Zebrafish Management Ltd | Wholesale & retail | 1997 |
| ZED Alpha Ltd | Administrative & support | 2022 |
| Zedra Solutions Ltd | Information & communication | 1999 |
| Zenrock Nominees Ltd | Extraterritorial | 2024 |
| ZEP Associates Limited | Professional & scientific | 2025 |
| Zero Minus One Ltd | Professional & scientific | 2024 |
| Zero Waste Group Limited | Water & waste | 2019 |
| Zest 4 Talent Ltd | Administrative & support | 2022 |
| Zeste Studio Ltd | Professional & scientific | 2013 |
| ZFX Limited | Professional & scientific | 2016 |
| Zilber Property Investment Limited | Professional & scientific | 2025 |
| Zone Garden Ltd | Manufacturing | 2025 |
| ZVC Geological Services Ltd | Mining & quarrying | 2026 |