| Womentum CIC | Education | 2024 |
| Wonderful Holidays Limited | Administrative & support | 2025 |
| Wonderwall Drylining and Plastering Limited | Construction | 2012 |
| Wongi Design & Build Ltd | Construction | 2011 |
| Wood & Glass Revival Ltd | Manufacturing | 2026 |
| Wood ASH Formes Limited | Manufacturing | 1979 |
| Wood ASH Group Holdings Limited | Financial services | 2021 |
| Wood ASH Press Knives Limited | Manufacturing | 1973 |
| Wood Corner Ltd | Wholesale & retail | 2025 |
| Wood Floors and Accessories Limited | Manufacturing | 1999 |
| Wood Prime Polishing Limited | Construction | 2017 |
| Wood Properties Ltd | Construction | 2019 |
| Woodend Investments Limited | Real estate | 2024 |
| Woodford Living Limited | Real estate | 2026 |
| Woodford Mauger Heritage Limited | Education | 2022 |
| Woodfords Group Ltd | Wholesale & retail | 2024 |
| Woodgrove Care Limited | Health & social care | 1997 |
| Woodhay Properties Limited | Real estate | 2021 |
| Woodix Ltd | Construction | 2026 |
| Woodparadise Limited | Construction | 2013 |
| Woodpecker Group Ltd | Construction | 2016 |
| Woodroom Ltd | Manufacturing | 2020 |
| Woods&Curtis Ltd | Transport & logistics | 2025 |
| Woodward Building Services Limited | Construction | 2002 |
| Woodward Holdings Ltd | Financial services | 2025 |
| Woodworks Design Limited | Construction | 2006 |
| Wool and Threads Ltd | Wholesale & retail | 2024 |
| Work OUT IT Limited | Information & communication | 2024 |
| Workex Limited | Education | 2019 |
| Workforce Capacity Ltd | Administrative & support | 2024 |
| Workmere Limited | Administrative & support | 2025 |
| Workpeach UK Ltd | Administrative & support | 2020 |
| Workwise City Limited | Administrative & support | 2022 |
| World Engine Specialist Ltd | Wholesale & retail | 2024 |
| World Events Management Services UK Ltd | Wholesale & retail | 2022 |
| World of 1DA Ltd | Administrative & support | 2007 |
| World Power Sound Limited | Information & communication | 2023 |
| World Tech Consultants Ltd | Information & communication | 2019 |
| World Trans Travel Ltd | Transport & logistics | 2025 |
| Worldguard K9 Security Ltd | Administrative & support | 2026 |
| Worldline UK Ltd | Wholesale & retail | 2018 |
| WOW Discoveries Ltd | Wholesale & retail | 2023 |
| WOW Pack Ltd | Wholesale & retail | 2023 |
| Woweffect Ltd | Construction | 2026 |
| WP Ferndale Property Ltd | Real estate | 2025 |
| Wpinvest Limited | Real estate | 2022 |
| WPM Electrical Services Ltd | Construction | 2022 |
| WPW Estates Ltd | Real estate | 2025 |
| Wrath Electrical Ltd | Construction | 2026 |
| Wray Construction Services Limited | Professional & scientific | 2022 |
| Wren's Removals Limited | Transport & logistics | 1960 |
| Wrenstone Capital Ltd | Financial services | 2025 |
| Wright's London Electrical Limited | Construction | 2019 |
| Wrights Maintenance Group Limited | Construction | 2024 |
| Wrist Holding UK Limited | Financial services | 2011 |
| WS Build Limited | Construction | 2016 |
| Wscr Limited | Hospitality | 2025 |
| Wsea Properties Limited | Real estate | 2024 |
| WT Operations Ltd | Administrative & support | 2023 |
| WTC Global Limited | Wholesale & retail | 2025 |
| Wtko Engineering Ltd. | Professional & scientific | 2016 |
| WU Tailor Ltd | Other services | 2016 |
| Wumpus Media Limited | Professional & scientific | 2025 |
| WWH Property Management Ltd | Construction | 2025 |
| WWW. Linzishoes Limited | Wholesale & retail | 2009 |
| WYR Property Investments Limited | Real estate | 2023 |
| Wyses Mews Management Limited | Households | 2017 |
| WZ Services Ltd | Information & communication | 2020 |
| X Vida Limited | Information & communication | 2025 |
| X6TRADES Ltd | Wholesale & retail | 2026 |
| Xadtech Limited | Information & communication | 2025 |
| Xanda KRD Ltd | Wholesale & retail | 2025 |
| Xavier-Mustard Investments Ltd | Financial services | 2023 |
| Xbio Limited | Administrative & support | 2017 |
| Xceed Capital Limited | Professional & scientific | 2024 |
| Xceedable Group Ltd | Administrative & support | 2025 |
| Xcel Aerospace Investments Limited | Professional & scientific | 2013 |
| Xcel Aerospace Limited | Manufacturing | 2011 |
| Xcel Aerospace Topco Limited | Professional & scientific | 2013 |
| Xcelentsolutions Ltd | Information & communication | 2019 |
| Xclusivista Limited | Wholesale & retail | 2014 |
| XEL Properties Ltd | Real estate | 2025 |
| Xenprosys Ltd | Information & communication | 2020 |
| Xeon Ventures Limited | Other services | 2024 |
| XEX Holdings Ltd | Professional & scientific | 2019 |
| Xhusi Ltd | Construction | 2024 |
| Ximitech Limited | Health & social care | 2006 |
| Xmechanic Ltd | Information & communication | 2025 |
| Xoshnaw KRD Ltd | Wholesale & retail | 2025 |
| Xpat Physiotherapy & Ventures Ltd | Wholesale & retail | 2025 |
| Xpert Telecom Limited | Information & communication | 2024 |
| Xplore United Company Limited | Wholesale & retail | 2022 |
| XRP Ripple Ltd | Administrative & support | 2023 |
| XS Global Limited | Wholesale & retail | 2017 |
| XS Showband Ltd | Arts & recreation | 2016 |
| Xspan Limited | Real estate | 2006 |
| Xtra Mile Properties Limited | Real estate | 2017 |
| Xtra Options Care Services Ltd | Health & social care | 2018 |
| Xtreme Source Ltd | Transport & logistics | 2018 |
| Xula Ltd | Wholesale & retail | 2025 |