| WEY2CREATIVE Limited | Information & communication | 2007 |
| Wheelers Mews Limited | Real estate | 2024 |
| Whirly Limited | Real estate | 2005 |
| White Lodge Centre | Education | 1981 |
| Will International Limited | Wholesale & retail | 2002 |
| Williams Cardiology Limited | Health & social care | 2015 |
| Windlebrook Property Management Limited | Households | 2014 |
| Windwheel Ltd | Wholesale & retail | 2021 |
| Winmore International Ltd | Information & communication | 2025 |
| Wise Wave Ventures Ltd | Hospitality | 2017 |
| WLO Services Ltd | Administrative & support | 2026 |
| Wocu Limited | Information & communication | 2008 |
| Wood House Consulting Ltd | Information & communication | 2019 |
| Woodcock Sash Windows Ltd | Manufacturing | 2020 |
| Woodford Building Services Limited | Administrative & support | 2002 |
| Woodward Group Holdings Ltd | Financial services | 2025 |
| Woodward Homes Ltd | Construction | 2023 |
| Wooft Recordings Ltd | Information & communication | 2019 |
| Wordsworth Consulting Limited | Other services | 2015 |
| Worldline Ventures Limited | Real estate | 2024 |
| Worldspan Communications Limited | Wholesale & retail | 1994 |
| WORLDWIDESOLUTIONS21 Ltd | Health & social care | 2021 |
| Wrapped Surrey Ltd | Wholesale & retail | 2026 |
| WRT Electric Ltd | Construction | 2017 |
| Xatrix Group Limited | Financial services | 2023 |
| Xavier Catholic Education Trust | Education | 2016 |
| Xcession Ltd | Information & communication | 2017 |
| XIX Professional Services Ltd | Professional & scientific | 2023 |
| XTP Consultants Limited | Administrative & support | 2010 |
| Y & S Enterprises London Limited | Other services | 2017 |
| Y Consulting Limited | Professional & scientific | 2000 |
| Y.T.D. Ltd | Wholesale & retail | 2006 |
| Yahel Jewellerys Ltd | Wholesale & retail | 2026 |
| Yaroni Wilken Services Limited | Administrative & support | 2026 |
| YDP Services Limited | Construction | 2025 |
| Yeates Property Services Limited | Energy | 2023 |
| Yendell Limited | Information & communication | 1986 |
| YI RAN Limited | Education | 2006 |
| Young People Limited | Financial services | 2013 |
| Your Childcare Business Ltd | Education | 2023 |
| YTD International Investment Limited | Real estate | 2022 |
| YTD Investment Limited | Real estate | 2017 |
| YTD Property Investment Limited | Real estate | 2022 |
| Yusuf Medical Solutions Limited | Health & social care | 2013 |
| Zaha Ventures Limited | Professional & scientific | 2019 |
| Zaha Weybridge Limited | Real estate | 2023 |
| Zaymash Holding Ltd | Administrative & support | 2018 |
| Zayz Limited | Construction | 2026 |
| Zeal Property Services Limited | Real estate | 2015 |
| Zero Nutrition Ltd | Wholesale & retail | 2024 |
| Zest of Mind Ltd | Professional & scientific | 2015 |
| Zetabird Limited | Information & communication | 2022 |
| Zetaloop Limited | Professional & scientific | 2026 |
| Zeus Perspective Information Planning Ltd | Wholesale & retail | 2024 |
| Zibeedo Ltd | Real estate | 2021 |
| Zonco Limited | Manufacturing | 2019 |
| Zuzon Self Storage Ltd | Real estate | 2024 |
| Zvenyika-Mubaiwa Investments Limited | Health & social care | 2016 |
| ZYT Ltd | Professional & scientific | 2024 |
| Zyzaa Limited | Wholesale & retail | 2022 |