| Wessex Timber Frame & Carpentry Ltd | Construction | 2025 |
| Wessex Towbar Services Ltd | Wholesale & retail | 2009 |
| Wessex Trees Limited | Agriculture & fishing | 2013 |
| West System International Limited | Manufacturing | 2012 |
| West Urology Limited | Health & social care | 2022 |
| Westfield Group UK Limited | Water & waste | 2007 |
| Weston Property Rental Limited | Real estate | 2016 |
| Weston Warmbloods Limited | Agriculture & fishing | 2014 |
| WH Development & Renovation Ltd | Construction | 2018 |
| Whinwhistle Ltd | Manufacturing | 2023 |
| Whispaire Limited | Manufacturing | 1996 |
| White Feather Developments Limited | Construction | 2012 |
| White Heron Partnership Limited | Financial services | 2019 |
| White Horse Family Investments Limited | Financial services | 2025 |
| White Volt Electrical and Renewables Ltd | Construction | 2025 |
| White Wave Web Solutions Limited | Professional & scientific | 2012 |
| Whitefox Design Ltd | Construction | 2020 |
| Wickborne Homes Limited | Construction | 2011 |
| Wicked Sick Holdings Limited | Financial services | 2024 |
| Wicked Sick Limited | Professional & scientific | 2017 |
| Widenet Computer Services Limited | Information & communication | 1998 |
| Widenet Services UK Limited | Extraterritorial | 1999 |
| Wilkie Morrison Sound Production Ltd | Arts & recreation | 2021 |
| Will Case Limited | Other services | 2026 |
| Will Davies Sculpture Ltd | Construction | 2024 |
| Willow Consultants & Technology Ltd | Information & communication | 2025 |
| Wiltshire Joint Solutions Limited | Health & social care | 2011 |
| Winchester Cocoa Company Limited | Manufacturing | 2014 |
| Winchester Fine Furniture Ltd | Wholesale & retail | 2025 |
| Winchester House (Romsey) Management Limited | Real estate | 2005 |
| Windfield Drive Management Company Limited | Households | 2025 |
| Window Painting Specialists Ltd | Administrative & support | 2017 |
| Window Repair Specialists Ltd | Construction | 2012 |
| Windwhistle Farms Limited | Agriculture & fishing | 1993 |
| Winter Medical Limited | Health & social care | 2022 |
| Winterslow Carriage Company Limited | Wholesale & retail | 2011 |
| Winterstoke Financial Management Limited | Professional & scientific | 2003 |
| Winton Healthcare Ltd | Health & social care | 2005 |
| Winton Imed Limited | Extraterritorial | 2004 |
| Wise Choice Financial Management Ltd | Professional & scientific | 2024 |
| Wise Structural Consulting Limited | Professional & scientific | 2012 |
| Wisteria Finance Limited | Professional & scientific | 2022 |
| WIZ Media Ltd | Information & communication | 2020 |
| WIZ Media Retail Ltd | Wholesale & retail | 2021 |
| WMH (2025) Limited | Arts & recreation | 2025 |
| Woodington Fisheries (2020) Ltd | Agriculture & fishing | 2020 |
| Woodmandrabble Ltd | Professional & scientific | 2018 |
| Woodpecker Estates (Southern) Ltd | Real estate | 2024 |
| Woodpeckers Childcare Limited | Health & social care | 2004 |
| Woodpeckers Properties Ltd | Real estate | 2022 |
| Woodworx Group Ltd | Financial services | 2017 |
| Woodworx Property Ltd | Administrative & support | 2025 |
| Woodworx Resort Ltd | Real estate | 2017 |
| Woodyard Mead Residents Management Co Ltd | Households | 2025 |
| Woolwich Central Residents Management Company Limited | Households | 2011 |
| Woolwich Central RTM Company Ltd | Households | 2026 |
| Workrat£ Ltd | Wholesale & retail | 2024 |
| Workspace Networks & Infrastructure Limited | Information & communication | 2025 |
| Woven Realms Ltd | Arts & recreation | 2023 |
| WOW Group Holdings Ltd | Financial services | 2026 |
| WOW Technologies Ltd | Information & communication | 2024 |
| Wren Games Ltd | Information & communication | 2018 |
| Wrist & Watch Co Ltd | Wholesale & retail | 2021 |
| Wyatt Luxury Homes Limited | Construction | 1996 |
| Wyborn Hotels Limited | Construction | 1997 |
| Wyborn Properties Limited | Professional & scientific | 2008 |
| Wynford Properties Limited | Real estate | 2000 |
| Xample Beats Ltd | Wholesale & retail | 2022 |
| Xcapism Learning Ltd | Education | 2020 |
| Xstimo Limited | Professional & scientific | 2023 |
| Yacht Wraps UK Limited | Manufacturing | 2018 |
| Yallingup Anaesthesia Limited | Health & social care | 2013 |
| Yitshak Enterprises Limited | Administrative & support | 2018 |
| YL Labs Ltd | Information & communication | 2025 |
| Your Loyalty Ltd | Information & communication | 2025 |
| Your Sports Education Ltd | Arts & recreation | 2016 |
| Youth in Romsey | Other services | 1997 |
| YS Lyndhurst Limited | Hospitality | 2025 |
| YS Romsey (Opco) Limited | Hospitality | 2025 |
| YS Romsey Limited | Hospitality | 2025 |
| Z Khan's Business Solutions Ltd. | Financial services | 2014 |
| ZAC Z Limited | Manufacturing | 2019 |
| Zaed Hamady Ltd | Health & social care | 2020 |
| ZAZ Art Ltd | Manufacturing | 2017 |
| ZAZ Records Ltd | Information & communication | 2008 |
| Zaza's Storybox Limited | Wholesale & retail | 2018 |
| Zeinex Ltd | Health & social care | 2014 |
| Zero Bridge Limited | Financial services | 2018 |
| ZIG ZAG Embroidery & Printing Limited | Manufacturing | 2018 |
| Zivow Limited | Wholesale & retail | 2025 |
| Zosa Ltd | Other services | 2020 |
| Zxnv Ltd | Real estate | 2021 |
| ZZZ Medical Services Ltd | Health & social care | 2023 |