| Wiggins Consulting Services Ltd | Information & communication | 2022 |
| Wilcro Limited | Wholesale & retail | 2024 |
| Wild 4 Construction Limited | Construction | 2005 |
| Wild Wild Western Wear Limited | Wholesale & retail | 2024 |
| Wild Wood Learning Limited | Real estate | 2026 |
| Will Large Rigging Services Ltd | Manufacturing | 2015 |
| Will TON Limited | Real estate | 2016 |
| William Glass & Company Limited | Professional & scientific | 2002 |
| Willow Gallery Ltd | Wholesale & retail | 2011 |
| Wills Etcetera Ltd | Financial services | 2024 |
| Wimbledon Village Montessori School Ltd | Education | 2017 |
| WIN Real Talisman Limited | Arts & recreation | 2022 |
| Winchfield Landscape Services Ltd | Administrative & support | 2001 |
| Wingtip Aviation Solutions Limited | Transport & logistics | 2017 |
| Winkelmann Countermeasures Limited | | 1981 |
| Wirehive Limited | Information & communication | 2005 |
| Wireless Navitas Limited | Manufacturing | 2018 |
| Wisdom Financial Management Ltd | Professional & scientific | 2017 |
| Wise Civils Ltd | Construction | 2022 |
| Wishy Washy Window Cleaning Limited | Other services | 2024 |
| With Hayley Duncombe Limited | Other services | 2025 |
| Witness Electrical Limited | Construction | 2025 |
| Wizardit Consulting Limited | Information & communication | 2004 |
| WLE Limited | Wholesale & retail | 2008 |
| Wlta Limited | Households | 2004 |
| WMS Express Ltd | Administrative & support | 2002 |
| WOK & Balti Limited | Hospitality | 2010 |
| WOK Kitchen Limited | Hospitality | 2019 |
| Wolf Fit Ltd | Wholesale & retail | 2025 |
| Women's Ballers Club Ltd | Education | 2025 |
| Woodford Stauffer Law Limited | Professional & scientific | 2016 |
| Woodlands (HB) Limited | Financial services | 2026 |
| Woodstreet Childcare & Forest School Limited | Health & social care | 2026 |
| Woodthorpe Properties Limited | Real estate | 2015 |
| Workman-Fowler Structures Ltd | Professional & scientific | 2020 |
| World Trade and Commerce Forum Ltd | Other services | 2017 |
| Worldwide Immigration Ltd | Professional & scientific | 2019 |
| Wraiths World Ltd | Information & communication | 2021 |
| Wrecclesham Tennis Club Limited | Arts & recreation | 1980 |
| Wurx Auto Ltd | Wholesale & retail | 2023 |
| Wyeknott Ltd | Information & communication | 2022 |
| Wyeth Burrell FOX Ltd | Real estate | 2024 |
| Wyeth Burrell Pearce Ltd | Real estate | 2023 |
| Wyeth Burrell Properties Ltd | Real estate | 2021 |
| Wyeth Christman Homes Ltd | Real estate | 2024 |
| Wynderra Limited | Information & communication | 2021 |
| Wyndham Street Management Company Ltd | Households | 2005 |
| X Section Limited | Professional & scientific | 2003 |
| Xchain Technologies Ltd | Financial services | 2023 |
| Xchanging B.V. | | 1999 |
| Xchanging Claims Services Limited | Financial services | 2001 |
| Xchanging Global Insurance Solutions Limited | Information & communication | 1952 |
| Xchanging Global Insurance Systems Limited | Professional & scientific | 1999 |
| Xchanging Holdings Limited | Professional & scientific | 2006 |
| Xchanging UK Limited | Professional & scientific | 1998 |
| Xclusive Aesthetics Ltd | Health & social care | 2016 |
| Xenon Life Sciences Ltd | Professional & scientific | 2021 |
| Xisco Ltd | Wholesale & retail | 2010 |
| Xpanse Limited | Professional & scientific | 2001 |
| Xpanse NO. 2 Limited | Professional & scientific | 2001 |
| XQ Fashion Ltd | Other services | 2024 |
| Y&F Property Investment Limited | Real estate | 2022 |
| YAN Property Investment Limited | Real estate | 2021 |
| Yanki Translation & Tutoring Limited | Professional & scientific | 2021 |
| Yardlease Properties Limited | Construction | 1990 |
| Yashemo Group Ltd | Administrative & support | 2025 |
| Yckh Property Investment Limited | Real estate | 2021 |
| YD Physio Ltd | Other services | 2016 |
| Year END Maintenance Ltd | Other services | 2025 |
| Yellow Cactus Lifestyle Limited | Wholesale & retail | 2018 |
| Yellow Diamond Business Services Limited | Professional & scientific | 2013 |
| Yellow Moon Consultancy Services Limited | Professional & scientific | 2015 |
| Yellow Payments Ltd | Information & communication | 2013 |
| YEM Theatre Productions C.I.C. | Arts & recreation | 2025 |
| Yieldplus.Uk International Trading and Consultancy Ltd | Wholesale & retail | 2018 |
| Yoga Gentle Limited | Other services | 2018 |
| YOGA1 Studios Ltd | Wholesale & retail | 2018 |
| Yogic Foods Ltd | Wholesale & retail | 2025 |
| Yogis Kerala Ayurveda Ltd | Other services | 2014 |
| Yopsi Motors Ltd | Administrative & support | 2024 |
| Yorkgate Limited | Construction | 1993 |
| YOU Asset Management Limited | Financial services | 2007 |
| Young Peoples Enterprise Limited | Hospitality | 2016 |
| Your Admin Hub Ltd | Administrative & support | 2017 |
| Your Beautiful Kitchen Limited | Wholesale & retail | 2018 |
| Your Cave Products Ltd | Wholesale & retail | 2026 |
| Your Choice PVT Limited | Extraterritorial | 2014 |
| Your Complete Services Limited | Construction | 2024 |
| Your Family First Ltd | Financial services | 2026 |
| Your Office Home Office Ltd | Professional & scientific | 2018 |
| Your Preferred Partners Limited | Professional & scientific | 2015 |
| Your Right Hand Finance Team Limited | Extraterritorial | 2007 |
| Yowyo Limited | Professional & scientific | 2013 |
| Yoxou Limited | Professional & scientific | 2023 |
| Ysnr Trading Ltd | Hospitality | 2024 |
| YU Property Investment Ltd | Real estate | 2020 |
| Yugan Technology Ltd. | Information & communication | 2015 |
| Yungdrung CIC | Education | 2025 |
| Zafety Supplies Ltd | Wholesale & retail | 2019 |
| Zero Emission Machinery Limited | Wholesale & retail | 2023 |