| West Coast Groundworks & R C Frames Limited | Construction | 2014 |
| West Kent Prison Services LLP | | 2015 |
| West London School of Guitar Limited | Education | 2016 |
| West One International Ltd | Information & communication | 2018 |
| Westcot House Design Ltd | Professional & scientific | 2022 |
| Westwood Grove (Ascot) Management Co Ltd | Households | 2024 |
| Wharfstorm Limited | Hospitality | 2012 |
| Wharram Percy Limited | Administrative & support | 2020 |
| What NOW Associates Limited | Professional & scientific | 2026 |
| Whatshalfway Ltd | Information & communication | 2022 |
| When I MET YOU Management Ltd | Information & communication | 2025 |
| Whisbean Limited | Professional & scientific | 2022 |
| White Star Properties Limited | Professional & scientific | 1999 |
| Whiteacre Limited | Construction | 2004 |
| Whitebeam Ltd | Administrative & support | 2002 |
| Whitecliff Vehicle Services Limited | Wholesale & retail | 2022 |
| Whitefoord Nominees Limited | Professional & scientific | 2010 |
| Whitefox Publishing Limited | Information & communication | 2012 |
| Whites Beaconsfield Limited | Health & social care | 2014 |
| Whitewall Properties Ltd | Real estate | 2020 |
| Whittaker Holdings Limited | Professional & scientific | 1994 |
| Whomp Ltd | Information & communication | 2024 |
| Wickham RYE & Co. Limited | Real estate | 1977 |
| Wide Blue (Perran) Limited | Real estate | 2023 |
| Wideland Limited | Real estate | 2001 |
| Widemarsh Gate Developments Limited | Construction | 1995 |
| Widmoor Finance Limited | Real estate | 1958 |
| Wigndorf Limited | Financial services | 2024 |
| Wild Environmental Limited | Professional & scientific | 2024 |
| Willander Properties Limited | Real estate | 2007 |
| William Philip Holdings Ltd | Financial services | 2024 |
| Willingham House & Co Ltd | Hospitality | 2024 |
| Willow Street Oswestry Ltd | Real estate | 2019 |
| Willowbrook Properties Limited | Real estate | 1993 |
| Willows Vehicle Sales Ltd | Wholesale & retail | 2024 |
| Wilton Park Properties Limited | Real estate | 2020 |
| Windsor END Court Management Company Limited | Households | 1996 |
| Wisdom Developments Limited | Construction | 2016 |
| Witneys Estates Limited | Real estate | 2020 |
| WM Programmes Ltd | Professional & scientific | 2013 |
| Woburn Sands Management Company Limited | Households | 2025 |
| Wolf Point (Residential) Limited | Real estate | 2019 |
| Wolf Point Limited | Real estate | 2003 |
| Wolfe Holdings Limited | Professional & scientific | 2021 |
| Wolfwyse Ltd | Information & communication | 2021 |
| Woodbourne Trading Limited | Professional & scientific | 2025 |
| Woodbridge Developments Ltd | Construction | 2026 |
| Woodcrest Building Services Limited | Construction | 2012 |
| Woodlands Devco Limited | Real estate | 2023 |
| Woodlands Grove (Ottershaw) Management Co Ltd | Households | 2024 |
| Woolf Partners Limited | Professional & scientific | 2022 |
| World Matters Limited | Professional & scientific | 2014 |
| World Natural Resources Limited | Mining & quarrying | 2012 |
| Worldweaver Limited | Information & communication | 1996 |
| WR Mediservices Limited | Health & social care | 2015 |
| Wrightland Partners Limited | Administrative & support | 2011 |
| Wycombe Driving School Ltd | Education | 2003 |
| Wycombe HS Limited | Professional & scientific | 2018 |
| Wycombe Management Services LLP | | 2018 |
| X212 Limited | Financial services | 2021 |
| Xanit Holdings Ltd | Financial services | 2024 |
| XG Finance Consulting Ltd | Professional & scientific | 2019 |
| Xpon Technologies Limited | Information & communication | 2016 |
| XTM International Limited | Information & communication | 2001 |
| Xyzdrycleaners Ltd | Other services | 2025 |
| Yellow Rose Desire Limited | Manufacturing | 2015 |
| Yellow Slice Ltd | Information & communication | 2025 |
| YHA Investments Limited | Financial services | 2022 |
| Yolland Garages Limited | Real estate | 1953 |
| Youclinic Limited | Health & social care | 2007 |
| Your Business Needs ME Ltd | Administrative & support | 2021 |
| Your Digital Profiles Limited | Information & communication | 2024 |
| Your Right to Light.Com Limited | Administrative & support | 2019 |
| Your Spec Ltd | Construction | 2025 |
| Yourstory Coaching Ltd | Professional & scientific | 2021 |
| Yuill Holdings Limited | Financial services | 2018 |
| Zaya Homecare Ltd | Health & social care | 2023 |
| Zbusiness Limited | Administrative & support | 2015 |
| Zeddco Ltd | Real estate | 2019 |
| Zenpro IT Solutions Ltd | Information & communication | 2012 |
| Zerothree Exhibitions Ltd | Administrative & support | 2002 |
| Zetter Trust Company Limited | Administrative & support | 2012 |
| Zing Magic Limited | Information & communication | 2003 |
| Zivtex Limited | Wholesale & retail | 1992 |
| Zychem Technologies Limited | Wholesale & retail | 2013 |
| Ísafjörður Consulting Ltd | Information & communication | 2025 |