| WH Smith PLC | Professional & scientific | 2004 |
| WH Smith Travel 2008 Limited | Professional & scientific | 2008 |
| WH Smith Travel Holdings Limited | Professional & scientific | 2006 |
| WH Smith Travel Limited | Wholesale & retail | 2008 |
| WH Smith US Group Holdings Limited | Financial services | 2018 |
| WH Smith US Retail Holdings Limited | Financial services | 2018 |
| Whanau Property Ltd | Real estate | 2021 |
| Wharf Properties (Wroughton) Limited | Real estate | 1994 |
| Wharf Street Ltd | Real estate | 2019 |
| Wharf Street South Developments Limited | Construction | 2009 |
| What Dogs Want Ltd | Education | 2026 |
| What You'Ve Always Wanted Ltd | Wholesale & retail | 2015 |
| Wheatleys Farm Management Company Limited | Households | 2020 |
| Whelford Pools Fisheries Ltd | Agriculture & fishing | 2018 |
| WHERE2PARK-AI Ltd | Information & communication | 2025 |
| Whim Hospitality Limited | Hospitality | 2020 |
| Whisky 78 Ltd | Wholesale & retail | 2017 |
| Whistledown View Management Company Limited | Households | 2020 |
| White & White Healthcare Ltd | Health & social care | 2024 |
| White Fluffy Cloud Limited | Information & communication | 2012 |
| White Glove Fulfilment Ltd | Transport & logistics | 2013 |
| White Horse Child Care Limited | Professional & scientific | 1989 |
| White Horse Consortium Limited | Construction | 2020 |
| White Horse Ferries Limited | Transport & logistics | 1991 |
| White Horse Games Ltd | Manufacturing | 2023 |
| White Horse Liveries (Alton Barnes) Limited | Arts & recreation | 2015 |
| White Horse Radar Limited | Professional & scientific | 2012 |
| White Horse Steel Installations Ltd | Professional & scientific | 2023 |
| White Lion LUX Limited | Wholesale & retail | 2020 |
| White Pennant Ltd | Financial services | 2010 |
| White Sands Computing Limited | Information & communication | 1999 |
| White Van Rental Limited | Administrative & support | 2026 |
| White-Spaces Cleaning Service Ltd | Administrative & support | 2025 |
| Whiteboard Publishing Ltd | Information & communication | 2015 |
| Whitefield Group (UK) Limited | Wholesale & retail | 2020 |
| Whitefriars Sailing Club Limited | Arts & recreation | 2025 |
| Whitegrove Limited | Hospitality | 2024 |
| Whitehaven Holdings Limited | Wholesale & retail | 2021 |
| Whiteley Aerospace Safety Engineering & Management Limited | Professional & scientific | 2009 |
| Whiteman Clark Ltd | Construction | 2023 |
| Whites Transport Services Limited | Transport & logistics | 1998 |
| Whitewater AI Ltd | Information & communication | 2020 |
| Whitmarsh Brooks Limited | Real estate | 2026 |
| Whitmarsh Lockhart Development Consultancy Ltd | Construction | 2004 |
| Whitmarsh Lockhart LLP | | 2010 |
| Whittle IT Services Ltd | Information & communication | 2026 |
| Whittle Woods Limited | Construction | 2002 |
| Whole System Coaching Ltd | Professional & scientific | 2024 |
| Wholesome Care 247 Limited | Public administration | 2024 |
| WHY NOT Adventures Ltd | Administrative & support | 2024 |
| WHY Windows Limited | | 1988 |
| Wichelstowe Residents' Management Company Limited | Households | 2009 |
| Wicked Wrld Ltd | Wholesale & retail | 2025 |
| Wickfield Properties Limited | Real estate | 2017 |
| Widdon Advisory Limited | Professional & scientific | 2026 |
| Widdon Capital Limited | Financial services | 2026 |
| Widham Engineering Ltd | Professional & scientific | 2026 |
| Wieldy Digital Ltd | Hospitality | 2018 |
| Wiesiek Trans Ltd | Transport & logistics | 2015 |
| Wigmore Star LLP | | 2025 |
| Wild at Lydiard Limited | Hospitality | 2024 |
| Wild Life World Limited | Manufacturing | 1997 |
| Wild Meadow Camping Limited | Hospitality | 2018 |
| Wild Optics Limited | Wholesale & retail | 2010 |
| Wild Thoughts Floristry Ltd | Wholesale & retail | 2020 |
| Wildman (Construction) Limited | Construction | 1984 |
| Wildman Construction (Swindon) Limited | Extraterritorial | 2002 |
| Wildman Property Developments Limited | Construction | 2000 |
| Wildridge and Co Limited | Manufacturing | 2025 |
| Wildwood Landscaping Ltd | Administrative & support | 2024 |
| Will Midlane Psychotherapy Ltd | Administrative & support | 2016 |
| Willenhall Healthcare Surgical Solutions Limited | Administrative & support | 2025 |
| William Arthur Limited | Real estate | 2015 |
| William Export Services Ltd | Other services | 2026 |
| William Marshal IP Limited | Financial services | 2025 |
| Williams Hsqe Services Ltd | Professional & scientific | 2026 |
| Willis Moss Limited | Wholesale & retail | 2007 |
| Willow & Olive Interiors Ltd | Manufacturing | 2017 |
| Willow 2020 Consulting Limited | Professional & scientific | 2019 |
| Willow Endeavours Ltd | Real estate | 2020 |
| Willow Tree Building Services Ltd | Construction | 2018 |
| Willow Tree Wills Ltd | Professional & scientific | 2021 |
| Willowandwhite Ltd | Manufacturing | 2022 |
| Wills & Blair Limited | Professional & scientific | 2015 |
| Wilmers Mews Residents Limited | Households | 2021 |
| Wilorlys Health Care Limited | Public administration | 2022 |
| Wilshire Investments Limited | Real estate | 2019 |
| Wilshire Jones Properties Ltd | Real estate | 2013 |
| Wilson Brothers Properties Limited | Real estate | 1991 |
| Wilson Cleaning Services Ltd | Administrative & support | 2012 |
| Wilson Construction and Maintenance Limited | Construction | 2020 |
| Wilson Harris Associates Limited | Professional & scientific | 2018 |
| Wilson Kimber Homes Ltd | Real estate | 2026 |
| Wilson Tool International [Europe] Limited | Manufacturing | 2006 |
| Wilts Inspection Services Ltd | Professional & scientific | 2025 |
| Wilts Windows Ltd | Other services | 2017 |
| Wiltshire and Avon Cash Registers Limited | Manufacturing | 1997 |
| Wiltshire Angling Limited | Wholesale & retail | 2014 |
| Wiltshire Asphalt Recycling Ltd | Construction | 2022 |
| Wiltshire Bathroom Design Limited | Construction | 2025 |