| Westbury Residents' Association Limited | Households | 1993 |
| Westleigh Heights Management Company Limited | Real estate | 2007 |
| Westside Studio Ltd | Information & communication | 2002 |
| Westwoods Joinery Limited | Construction | 2010 |
| WFF Building Ltd | Construction | 2012 |
| What a Life Productions Ltd | Arts & recreation | 2016 |
| What Mums EAT Ltd | Hospitality | 2025 |
| White Willow Homes Ltd | Construction | 2023 |
| Whitecrest Consulting Ltd | Other services | 2026 |
| Whitetop Management Limited | Administrative & support | 2011 |
| Whittaker Designs Limited | Professional & scientific | 2024 |
| Whittle Carpentry Limited | Construction | 2011 |
| Whittle Electrical Services Ltd | Construction | 2021 |
| Whizbe Associates Limited | Construction | 2023 |
| Whizbe Compliance Services Limited | Construction | 2024 |
| Whole Life Therapy Ltd | Health & social care | 2013 |
| Wholesale POS Ltd | Wholesale & retail | 2018 |
| Wilder Utilities Limited | Energy | 2024 |
| Wilkinson Mortgage Advice Limited | Financial services | 2022 |
| William and Ashley Group Ltd | Construction | 2023 |
| Williams Clarke Decorating Limited | Construction | 2016 |
| Willow Transport Solutions Limited | Transport & logistics | 2013 |
| Willy Weston Ltd | Construction | 2017 |
| Wilsons Engineering (S E) Limited | Professional & scientific | 2016 |
| Windors Aluminium Ltd | Construction | 2018 |
| Window Wise (Essex) Limited | Manufacturing | 2009 |
| Windscreen Insurance Services Ltd | Financial services | 2003 |
| Windward Trading Company Ltd | Wholesale & retail | 2011 |
| Wing Tingz Ltd | Hospitality | 2024 |
| Wingcontrol Limited | Wholesale & retail | 2026 |
| Wise CG Ltd | Administrative & support | 2025 |
| Wisteria Court Freehold Company Limited | Other services | 2010 |
| Wisteria Court Residents Management Company Limited | Households | 2009 |
| With Conviction CIC | Health & social care | 2026 |
| With Love, Wilson Limited | Wholesale & retail | 2016 |
| WJT Homes Ltd | Construction | 2021 |
| Women Inspired Ltd | Information & communication | 2014 |
| Wonderlab Hair and Beauty Ltd | Other services | 2011 |
| Woodlands Holiday Cottages Ltd | Real estate | 2007 |
| Woodlyn Estates Ltd | Real estate | 2015 |
| Woods Paving Limited | Administrative & support | 2023 |
| Words on Toast Ltd | Administrative & support | 2020 |
| Workforce Solutions UK Division Ltd | Information & communication | 2024 |
| Worldwide Freight Services Limited | Transport & logistics | 2004 |
| Worrin Estates Limited | Real estate | 2015 |
| Wright and Co Barbers Ltd | Other services | 2024 |
| Wysock-Wright & Co. Limited | Extraterritorial | 2013 |
| Wyvern Community Transport | Transport & logistics | 2005 |
| X42 Limited | Administrative & support | 2016 |
| Xavidan Consulting Limited | Information & communication | 2021 |
| Xaylo Limited | Information & communication | 2020 |
| Xbox ERA Ltd | Information & communication | 2020 |
| Xclusive Lines Ltd | Wholesale & retail | 2022 |
| Xibeo Limited | Manufacturing | 2025 |
| Xin's Property & Services Ltd | Real estate | 2023 |
| XL Creations Limited | Professional & scientific | 2013 |
| XSO Trading Limited | Wholesale & retail | 2023 |
| Y.O.P Ltd | Other services | 2016 |
| Yamo Ltd | Construction | 2025 |
| Yellow Stone Ventures Limited | Real estate | 2021 |
| Yemaji Limited | Health & social care | 2023 |
| Yewjutsu Limited | Education | 2020 |
| YK Music Warehouse Ltd | Information & communication | 2026 |
| YOGA4ALL Group Community Interest Company | Health & social care | 2020 |
| Your Bourse Hosting Ltd | Information & communication | 2015 |
| Your Bourse Limited | Information & communication | 2013 |
| Yourcastle Limited | Construction | 2023 |
| Zachzada Ltd | Administrative & support | 2023 |
| Zarahemla Consulting Limited | Professional & scientific | 2009 |
| Zarahemla Limited | Real estate | 2008 |
| Zarautz Limited | Real estate | 2010 |
| Zeal Property Investments Ltd | Real estate | 2024 |
| Zenith Multi Academy Trust | Education | 2011 |
| Zerons Publications Limited | Information & communication | 2021 |
| Zeus Electrical Installations Ltd | Construction | 2025 |
| Zing Mortgages Essex Ltd | Financial services | 2019 |
| Zing Mortgages Limited | Extraterritorial | 2016 |
| Zizi Events Ltd | Professional & scientific | 2022 |
| Zoeeden Limited | Manufacturing | 2012 |
| ZT Fitness Ltd | Arts & recreation | 2024 |
| Zubba Limited | Information & communication | 2012 |
| Élevé Medical Ltd | Health & social care | 2025 |