| Woodfourd Limited | Financial services | 2020 |
| Woodhouse Interiors Ltd | Construction | 2021 |
| Woodhurst Solutions Limited | Administrative & support | 2016 |
| Woodland Property Limited | Real estate | 2006 |
| Woodland Wilds Ltd | Education | 2019 |
| Woodleigh Flats Limited | Households | 1970 |
| Woodredon House Limited | Real estate | 2024 |
| Woodupp Limited | Manufacturing | 2019 |
| Woolden House Management Limited | Households | 1962 |
| Woolley Heating & Plumbing Limited | Construction | 2026 |
| Workout Limited | Real estate | 2003 |
| Wornword Limited | Wholesale & retail | 2025 |
| Wraith Marketing Limited | Professional & scientific | 2016 |
| Wrapid Paper Limited | Manufacturing | 2015 |
| Wras Management Limited | Households | 1994 |
| Wroths Solutions Ltd | Information & communication | 2014 |
| WS Venture Limited | Hospitality | 2019 |
| WSC Books Ltd | Information & communication | 1998 |
| WT Nova Ltd | Other services | 2019 |
| Wyndhaven Ltd | Construction | 2013 |
| Wysefox Limited | Information & communication | 2025 |
| X a Insulation and Render Ltd | Construction | 2022 |
| X-Clusive Ideas Ltd | Other services | 2018 |
| XA Mattress Limited | Wholesale & retail | 2018 |
| Xavier Property Management (UK) 2021 Limited | Real estate | 2020 |
| Xpert Media Solutions Ltd | Professional & scientific | 2025 |
| Xplorers Trading Limited | Wholesale & retail | 2023 |
| Xpressions of ME Ltd | Wholesale & retail | 2020 |
| Xsure Labs Ltd | Information & communication | 2019 |
| Xtreme Trailers Ltd | Manufacturing | 2024 |
| Y@H Ltd. | Professional & scientific | 2017 |
| Yamatsune UK Ltd | Wholesale & retail | 2017 |
| Yamuk Investments Limited | Real estate | 2022 |
| YAWEH777 Ltd | Health & social care | 2024 |
| YBC London Ltd | Other services | 2022 |
| Yellow Fever Limited | Professional & scientific | 2012 |
| Yellowbus Investments Limited | Administrative & support | 2001 |
| Yelto Limited | Hospitality | 2024 |
| Yenei Tinley Chiropractic Limited | Public administration | 2024 |
| Yewacre Limited | Administrative & support | 2004 |
| YGK Limited | Information & communication | 2013 |
| YMA Bouncy Castles Ltd | Transport & logistics | 2022 |
| YN Management Consultant Ltd | Information & communication | 2011 |
| YO Life Limited | Other services | 2014 |
| Yog-Art Limited | Wholesale & retail | 2024 |
| Yolkstone Limited | Administrative & support | 2004 |
| York Hill Estates Ltd | Real estate | 2017 |
| York Hill Property Investments Ltd | Real estate | 2016 |
| York House (Upper Montagu Street) Limited | Real estate | 1991 |
| Your Brand Mark Ltd | Information & communication | 2021 |
| Your Business Community Limited | Other services | 2014 |
| Your Chauffeur Limited | Transport & logistics | 2017 |
| Your Fitter Ltd | Construction | 2017 |
| Your Game Plan Ltd | Education | 2019 |
| Your Home Removal 1 Ltd | Transport & logistics | 2025 |
| Your Mum's House Management Ltd | Arts & recreation | 2015 |
| Your Space Design and Build Limited | Construction | 2017 |
| YSR Property Management Ltd | Real estate | 2025 |
| Yumi’S World Limited | Wholesale & retail | 2025 |
| Yvmv Studios Ltd | Professional & scientific | 2022 |
| Z & S Enterprises Limited | Professional & scientific | 2013 |
| Z K Invest Ltd | Households | 2024 |
| ZA Hawk Services Ltd | Administrative & support | 2025 |
| Zacharian Nichope Limited | Households | 2025 |
| Zack Consulting Limited | Administrative & support | 2022 |
| Zahin Venture Limited | Wholesale & retail | 2023 |
| Zahra H Limited | Transport & logistics | 2018 |
| Zainab Duty Free Worldwide Ltd | Wholesale & retail | 2006 |
| Zainab Limited | Wholesale & retail | 2000 |
| Zaniah Developments Limited | Information & communication | 2005 |
| Zapptax Limited | Other services | 2017 |
| Zarko (BG) Limited | Transport & logistics | 2016 |
| Zealand Management (UK) Limited | Administrative & support | 2004 |
| ZEN Fit FUN Limited | Public administration | 2025 |
| ZEN Mind Ltd | Health & social care | 2020 |
| ZEN Signs Ltd | Professional & scientific | 2024 |
| Zena Consulting Ltd | Administrative & support | 2024 |
| Zencudo Limited | Information & communication | 2002 |
| Zenith Advisory Ltd | Construction | 2019 |
| Zero-Zero Technologies Ltd | Professional & scientific | 2014 |
| Zerodown Limited | Real estate | 2005 |
| Zesah Holding Limited | Financial services | 2025 |
| Zest (PM) Ltd | Information & communication | 2003 |
| Zest Salad Limited | Hospitality | 2022 |
| Zestplan Limited | Administrative & support | 2007 |
| ZHM Engineering Ltd | Construction | 2023 |
| Znlk Limited | Professional & scientific | 2012 |
| Zodiac Protection Limited | Administrative & support | 2025 |
| Zone Global Limited | Wholesale & retail | 2017 |
| Zone Health and Performance Limited | Health & social care | 2020 |
| ZONE3 London Ltd | Professional & scientific | 2015 |
| Zorani Holdings Ltd | Real estate | 2021 |
| ZR Southall Limited | Construction | 2020 |
| Zsfba Limited | Education | 2025 |
| ZV Electrics Limited | Construction | 2023 |
| ZWH (Modular UK) Ltd | Construction | 2021 |
| Zylo Build Limited | Construction | 2022 |