| WPB Supplys Ltd | Wholesale & retail | 2025 |
| Wren & Co Building Ltd | Construction | 2020 |
| Wren Essex Electrical Services Ltd | Other services | 2020 |
| Wren Packaging Limited | Other services | 2013 |
| WS Associates (UK) Ltd | Administrative & support | 1997 |
| WS Partners Limited | Extraterritorial | 2015 |
| Wsr&Mgu Drive Ltd | Transport & logistics | 2025 |
| WSS Digital Ltd | Information & communication | 2011 |
| Wycombe Coin Limited | Arts & recreation | 1980 |
| Wynn Mediation Limited | Administrative & support | 2012 |
| Wynnstay HJD Limited | Hospitality | 2020 |
| X Active Construction Group Limited | Construction | 2023 |
| X-Isle (Essex) Limited | Wholesale & retail | 2005 |
| Xanadu Media Group Ltd | Professional & scientific | 2019 |
| Xavar Limited | Real estate | 2024 |
| Xavier Remi Limited | Real estate | 2024 |
| Xeinadin South Essex Limited | Professional & scientific | 2012 |
| Xenium Lake Ltd | Real estate | 2021 |
| XP Real Estate Limited | Real estate | 2026 |
| Xperformax Ltd | Administrative & support | 2024 |
| Xpress Pest Control Limited | Administrative & support | 2023 |
| XVT Limited | Other services | 2022 |
| Yaden Locke Ltd | Professional & scientific | 2026 |
| YAG Kanani Consulting Limited | Information & communication | 2010 |
| Yaree Limited | Wholesale & retail | 2025 |
| Yasu KOI Ltd | Wholesale & retail | 2025 |
| Yearley Tax Ltd | Professional & scientific | 2018 |
| Yeates Plastering Limited | Construction | 2015 |
| Yellow APE Ltd | Wholesale & retail | 2019 |
| Yellow Bram Limited | Administrative & support | 2019 |
| Yellow Land Limited | Real estate | 2016 |
| Yieldtree Commercial Ltd | Real estate | 2026 |
| Ylli Holdings Limited | Financial services | 2017 |
| Ymoon Limited | Administrative & support | 2015 |
| YO & LI Build Limited | Construction | 2020 |
| Yogabum Limited | Wholesale & retail | 2010 |
| York Lodge (Southend) Management Company Limited | Households | 1987 |
| Young Fincrime Professionals Ltd | Other services | 2024 |
| Your Business Guide Limited | Administrative & support | 2020 |
| Your Financial Compass Ltd | Financial services | 2024 |
| Your Red Dress Ltd | Administrative & support | 2016 |
| Your Space Designed for YOU Ltd | Construction | 2022 |
| Your Viewfinder Ltd | Wholesale & retail | 2025 |
| Yowsun Care Ltd | Health & social care | 2024 |
| Ypool Limited | Administrative & support | 2021 |
| Yumlii Limited | Information & communication | 2026 |
| Z F L Property Limited | Real estate | 2016 |
| Zabar Ltd | Construction | 2025 |
| ZAC Barbers Limited | Other services | 2023 |
| Zain Shah Limited | Real estate | 2018 |
| Zaintop Technical Services Limited | Construction | 2025 |
| Zakida Private Ltd | Real estate | 2002 |
| Zam-Beverages Ltd | Wholesale & retail | 2024 |
| Zama Engineering Consultancy Limited | Professional & scientific | 2025 |
| Zambahola Ltd | Wholesale & retail | 2025 |
| Zanom Ltd | Wholesale & retail | 2022 |
| ZAP Print Ltd | Manufacturing | 2025 |
| Zarct Limited | Hospitality | 2022 |
| Zassy Aesthetics Ltd | Other services | 2024 |
| Zaynu Ltd | Wholesale & retail | 2022 |
| Zayyan Sheikh Ltd | Health & social care | 2018 |
| Zegaal Homes Ltd | Real estate | 2022 |
| Zena Construction Ltd | Construction | 2021 |
| Zezo 1 Ltd | Wholesale & retail | 2025 |
| Ziggurat Communications Limited | Information & communication | 1998 |
| Zimfari Biltong Ltd | Wholesale & retail | 2018 |
| Zinnipops Ltd | Arts & recreation | 2024 |
| Zion Financial Services Ltd | Financial services | 2019 |
| Zion Mortgage Ltd | Financial services | 2023 |
| ZIP Scaffolding Ltd | Construction | 2025 |
| Zishan Brasserie Ltd | Hospitality | 2018 |
| Ziva Logistics Ltd | Transport & logistics | 2025 |
| ZNC Care Limited | Health & social care | 2012 |
| Znth Limited | Information & communication | 2026 |
| Zoff Limited | Real estate | 2019 |
| Zoom Ahead Limited | Other services | 2004 |
| Zouvelou Haematology Services Ltd | Health & social care | 2016 |
| ZPD UK Ltd | Construction | 2009 |
| ZPR Futures Limited | Financial services | 2020 |
| Zubeda Radiology Services Ltd | Health & social care | 2012 |
| Zwip Ltd | Education | 2026 |
| Zydek Limited | Transport & logistics | 2021 |