| WSN Crayford Limited | Hospitality | 2024 |
| WTF Transport Company Ltd | Transport & logistics | 2024 |
| Wuling Europe Limited | Wholesale & retail | 2026 |
| WWT Solutions Limited | Water & waste | 2024 |
| Www.Money Ltd | Extraterritorial | 2006 |
| Wych Elms Consulting Limited | Professional & scientific | 2022 |
| X123 Ltd | Information & communication | 2026 |
| Xanthosia Limited | Hospitality | 2003 |
| Xcite-Inspire Ltd | Information & communication | 2025 |
| Xenon Recruitment Freelance Limited | Administrative & support | 2024 |
| Xenon Recruitment Limited | Construction | 2019 |
| Xenon Recruitment Professional Services Limited | Administrative & support | 2024 |
| Xeunoiam Ltd | Professional & scientific | 2026 |
| XI Holdings Ltd | Financial services | 2021 |
| XI Leisure Ltd | Arts & recreation | 2021 |
| Xiangli & Co. Ltd | Professional & scientific | 2012 |
| XIN Chen Ltd | Hospitality | 2024 |
| XIX Valeting Ltd | Wholesale & retail | 2020 |
| XL Group Holdings Limited | Wholesale & retail | 2025 |
| XL Quotations Ltd | Information & communication | 2025 |
| Xrgroup Limited | Administrative & support | 2022 |
| Xsquares Holdings Limited | Real estate | 2021 |
| Xtracare Ltd | Real estate | 2005 |
| Xtreme Vortex Limited | Other services | 2017 |
| Xygon Computers Limited | Real estate | 1988 |
| Y M Direct Services Ltd | Health & social care | 2010 |
| Yah-Tech Group Ltd | Information & communication | 2022 |
| Yankoshomes Limited | Real estate | 2023 |
| Yankostech Limited | Information & communication | 2016 |
| Yasin Fikri Limited | Wholesale & retail | 2025 |
| Yates Invest Ltd | Real estate | 2024 |
| Yaww Ltd | Other services | 2018 |
| YB Financial Services Ltd | Administrative & support | 2018 |
| YBM Global Limited | Administrative & support | 2022 |
| Yeah Nice Studio Ltd | Professional & scientific | 2026 |
| Yellow Sage Limited | Education | 2024 |
| Yellowjacket Limited | Administrative & support | 2002 |
| Yelverton GU Ltd | Construction | 2020 |
| Yelverton PS Ltd | Construction | 2020 |
| Yeoman Street Ltd | Construction | 2017 |
| Yeomans M&E Ltd | Manufacturing | 2013 |
| YES Homes Limited | Real estate | 2013 |
| YES Nation Ltd. | Other services | 2024 |
| Yeshua Consultancy Ltd | Information & communication | 2021 |
| Yesod Kombat Ltd | Manufacturing | 2026 |
| Yeye Special Kitchen Limited | Hospitality | 2024 |
| Yhsg Global Limited | Professional & scientific | 2026 |
| YI Atelier Ltd | Manufacturing | 2026 |
| Yida Ltd | Wholesale & retail | 2023 |
| YIN MON Aung Ltd | Health & social care | 2026 |
| YL Contemporary Ltd | Wholesale & retail | 2024 |
| Yocol Trading Service Ltd | Administrative & support | 2013 |
| YOCT2022 Ltd | Hospitality | 2022 |
| Yoh's Pawa Haus Herbal Tea Ltd | Wholesale & retail | 2025 |
| Yolad Homes Limited | Real estate | 2021 |
| Yolan Ltd | Information & communication | 2015 |
| Yorkshire Desserts Ltd | Hospitality | 2016 |
| Yorlet Payments UK Ltd | Information & communication | 2022 |
| YOU Living Limited | Wholesale & retail | 2006 |
| Young Way Limited | Information & communication | 2020 |
| Youngco Fitness Ltd | Arts & recreation | 2026 |
| Younger & Co Ltd | Real estate | 2024 |
| Your Body Vibes Ltd | Wholesale & retail | 2025 |
| Your Building Company Ltd | Construction | 2025 |
| Your Property Accountant Limited | Professional & scientific | 2006 |
| Your Property Ltd | Real estate | 2017 |
| Your Sisters Wardrobe Ltd | Wholesale & retail | 2024 |
| Yourukcompetitions Ltd | Wholesale & retail | 2025 |
| Yous Barber Dartford Ltd | Other services | 2025 |
| Yova Properties Ltd | Transport & logistics | 2025 |
| Yova Technologies Ltd | Information & communication | 2024 |
| YS Cambridge Consulting & Service Ltd | Professional & scientific | 2025 |
| Yshg Limited | Information & communication | 2025 |
| YSS Home Builders Ltd | Construction | 2022 |
| Ytrs Consulting Services Ltd | Information & communication | 2025 |
| Yuli Ltd | Health & social care | 2020 |
| Yuonair Ltd | Information & communication | 2021 |
| YUP! Properties Limited | Real estate | 2024 |
| Yuvam Catering Limited | Hospitality | 2016 |
| YV Shells Ltd | Arts & recreation | 2022 |
| Z & K Fast Food Ltd | Wholesale & retail | 2017 |
| Z Bert Ltd | Manufacturing | 2019 |
| Z Peart Ltd | Professional & scientific | 2026 |
| Z2S Education Pathway Ltd | Administrative & support | 2025 |
| Z4 Health Ltd | Health & social care | 2025 |
| Zaara 1 Limited | Hospitality | 2016 |
| Zabbay Ltd | Wholesale & retail | 2026 |
| Zabeth Homes Ltd | Real estate | 2021 |
| Zack Contractors Ltd | Construction | 2016 |
| Zafer Limited | Real estate | 2024 |
| Zahir Jiwan Ltd | Health & social care | 2011 |
| Zalak Food Ltd | Hospitality | 2023 |
| Zamat Tech Ltd | Wholesale & retail | 2025 |
| Zander Mackenzie Care U.K. Limited | Health & social care | 2020 |
| Zander Mackenzie Ltd | Information & communication | 2011 |
| ZAP Property Ltd | Construction | 2021 |
| Zavi Limited | Administrative & support | 2009 |
| Zaye Ltd | Information & communication | 2021 |
| ZB Business Services Ltd | Administrative & support | 2012 |
| ZB Commercial Ltd | Financial services | 2024 |