| Wxllnxss Ltd | Wholesale & retail | 2020 |
| Wychwood Syndicate Ltd | Wholesale & retail | 2025 |
| Wycke Hill Developments Limited | Real estate | 2020 |
| Wyeth Security Services Limited | Administrative & support | 2013 |
| Wyldfield Homes Ltd | Real estate | 2022 |
| Wymak Metals Recycling Ltd | Manufacturing | 2017 |
| Wymak Properties Ltd | Construction | 2024 |
| Wynter Heating Ltd | Construction | 2025 |
| Wynwood Developments Limited | Real estate | 2023 |
| Wynwood Real Estate Ltd | Real estate | 2024 |
| WYS LDN Ltd | Manufacturing | 2017 |
| WZH Holdings Ltd | Financial services | 2023 |
| X Lewis Properties Ltd | Real estate | 2024 |
| X Lewis Services Ltd | Information & communication | 2021 |
| X Property 1 Ltd | Real estate | 2026 |
| X Property 2 Limited | Real estate | 2024 |
| X Property Projects Ventures Ltd | Real estate | 2019 |
| X-Tra X-Press Property Services Ltd | Real estate | 2010 |
| X.F.G. Limited | Wholesale & retail | 2016 |
| X3NA Consults Ltd | Professional & scientific | 2022 |
| Xamba Ltd | Wholesale & retail | 2025 |
| Xanco Facilities Management Ltd | Administrative & support | 2025 |
| Xandor Ltd | Wholesale & retail | 2026 |
| Xangi Ltd | Wholesale & retail | 2025 |
| Xanisys Limited | Wholesale & retail | 2014 |
| Xansa Limited | Information & communication | 2014 |
| Xaris Ltd | Real estate | 2012 |
| XAU USD Ltd | Hospitality | 2026 |
| Xavierstores Ltd | Wholesale & retail | 2023 |
| Xavsa Investments Limited | Financial services | 2017 |
| Xaymaca Music Studio Ltd | Manufacturing | 2025 |
| Xcel Productions Limited | Information & communication | 2011 |
| Xcel Resources Limited | Information & communication | 2011 |
| Xcel Trade Services Limited | Wholesale & retail | 2020 |
| Xcess Consultancy Limited | Information & communication | 2012 |
| Xchange Sales & Lettings Limited | Real estate | 2015 |
| Xcom Ltd | Information & communication | 2015 |
| Xcons Solutions Ltd | Information & communication | 2024 |
| XD Claims Ltd | Financial services | 2026 |
| Xecutive Direct Ltd | Transport & logistics | 2014 |
| Xela Cornwall Limited | Hospitality | 2020 |
| Xeva Design Ltd | Professional & scientific | 2017 |
| Xgeno Solutions Ltd | Information & communication | 2025 |
| Xiao FAN Limited | Professional & scientific | 2015 |
| Xidebuilders Ltd | Construction | 2019 |
| Xlab Innovations Ltd | Professional & scientific | 2025 |
| Xline Architecture Limited | Construction | 2020 |
| XLS Electrical Services Ltd | Construction | 2010 |
| XM Sourcing Hub Ltd | Wholesale & retail | 2023 |
| XMH Limited | Wholesale & retail | 2025 |
| Xolt Ltd | Wholesale & retail | 2020 |
| Xorta Solutions Limited | Wholesale & retail | 2022 |
| Xove Media Ltd | Information & communication | 2025 |
| Xoverx Ltd | Information & communication | 2012 |
| XPAC3 Ltd | Information & communication | 2023 |
| Xperia Motors Ltd | Wholesale & retail | 2015 |
| Xpert Digital Ltd | Information & communication | 2026 |
| Xpert Holdings Limited | Financial services | 2016 |
| Xpert Squad Ltd | Construction | 2024 |
| Xpertz Solution Ltd | Education | 2008 |
| Xponential Coaching Ltd | Professional & scientific | 2020 |
| Xpress Buyer Limited | Wholesale & retail | 2012 |
| Xpress Chauffeurs Ltd | Transport & logistics | 2017 |
| Xpress Packages Ltd | Transport & logistics | 2019 |
| Xpress Parcel Ltd | Transport & logistics | 2023 |
| Xpress Tyres and Service Centre Ltd | Wholesale & retail | 2021 |
| Xpress [SE] Ltd | Transport & logistics | 2021 |
| Xpropertyprojects Ltd | Real estate | 2019 |
| Xprt Subcontractors Limited | Wholesale & retail | 2025 |
| Xtorq Ltd | Wholesale & retail | 2025 |
| Xtractmedia Ltd | Information & communication | 2021 |
| XTREMECOSMETICS4U Ltd | Wholesale & retail | 2019 |
| XTREMEK9 Limited | Manufacturing | 2019 |
| Xuvas Group Ltd | Construction | 2022 |
| XWE Ltd | Information & communication | 2025 |
| Xyris Labs Ltd | Wholesale & retail | 2023 |
| XYZ Investment Group Ltd | Wholesale & retail | 2023 |
| XZS Property Group Ltd | Construction | 2021 |
| Y & U Properties Ltd | Real estate | 2014 |
| Y Autohub Ltd | Wholesale & retail | 2026 |
| Y D a Consultants Ltd | Other services | 2012 |
| Y H Designs Ltd | Professional & scientific | 2019 |
| Y NOT Consult Co. Ltd | Manufacturing | 2026 |
| Y PAL Hospitality Ltd | Wholesale & retail | 2021 |
| Y PAL Limited | Administrative & support | 2023 |
| Y Patel Limited | Wholesale & retail | 2011 |
| Y S M Property Investments Ltd | Construction | 2026 |
| Y Technologies Limited | Information & communication | 2021 |
| Y&F Property Management Limited | Construction | 2024 |
| Y&H Consulting Ltd | Professional & scientific | 2023 |
| Y&H Properties LLP | | 2018 |
| Y&N Patel Ltd | Real estate | 2022 |
| Y&N Services Limited | Wholesale & retail | 2024 |
| Y.K. Holdings London Limited | Professional & scientific | 2012 |
| Y.S Trade Ltd | Manufacturing | 2017 |
| Y1 Developers UK Ltd | Administrative & support | 2016 |
| Y2K Services Limited | Transport & logistics | 2019 |
| Y3 Apex Services Limited | Wholesale & retail | 2020 |
| Yaahvi Limited | Real estate | 2017 |
| Yaar UK TOH Ltd | Arts & recreation | 2021 |