| William Cheetham & SON Limited | Administrative & support | 1957 |
| William Cook Defence Limited | Extraterritorial | 2011 |
| William Cook Foundry (TOW Law) Limited | Extraterritorial | 1914 |
| William Cook Intermodal Limited | Manufacturing | 1980 |
| William Cook Leaseholds Limited | Real estate | 2010 |
| William Cook Machining Limited | Extraterritorial | 2015 |
| William Cook Publishing Limited | Information & communication | 2010 |
| William Cook Rail Limited | Manufacturing | 2013 |
| William Cook Stanhope Limited | Manufacturing | 1940 |
| William Elliott Boiler Services Limited | Manufacturing | 1946 |
| William Gosney Limited | Agriculture & fishing | 1965 |
| William H Williams Limited | Administrative & support | 2016 |
| William Howe & SON (Fish Merchants) Limited | Wholesale & retail | 1956 |
| William Hunt & Sons (the Brades) Limited | Extraterritorial | 1997 |
| William Knight Properties Limited | Real estate | 2023 |
| William Marsden & SON Limited | Agriculture & fishing | 1955 |
| William R Craig Associates Limited | Professional & scientific | 2019 |
| William Rowland Metal Finishing Limited | Manufacturing | 1940 |
| William Smith Tool & Steel Company Limited | Extraterritorial | 1997 |
| William Talbot Limited | Real estate | 1954 |
| William Whiteley & Sons (Sheffield) Limited | Manufacturing | 1997 |
| William's Serviced Apartments Ltd | Real estate | 2016 |
| Williams Askew Wealth Management Limited | Financial services | 2014 |
| Williams Electrical & Mechanical Services Limited | Wholesale & retail | 1999 |
| Williams Financial Management Ltd | Financial services | 2012 |
| Williams Property Agency Ltd | Real estate | 2019 |
| Williamson Road Holdings Ltd | Real estate | 2018 |
| Willis Developments UK Limited | Construction | 2007 |
| Williwaw UK Limited | Wholesale & retail | 2003 |
| Willow & Thyme Group Limited | Manufacturing | 2021 |
| Willow & Thyme Home Fragrance Ltd | Wholesale & retail | 2017 |
| Willow Construction (North) Limited | Construction | 2003 |
| Willow Crest Cawood Management Company Limited | Households | 2020 |
| Willow Damp Proofing Ltd | Construction | 2015 |
| Willow FOX Hairdressing Ltd | Other services | 2024 |
| Willow House (Flats Management) Limited | Households | 1987 |
| Willow Properties & Lettings Ltd | Real estate | 2017 |
| Willow Refurb Ltd | Construction | 2024 |
| Willow Tree Cattery Ltd | Other services | 2022 |
| Willow Tree Decor Ltd | Wholesale & retail | 2022 |
| Willow Tree Place (Pond) Ltd | Construction | 2011 |
| Willow Tree Place Management Company Ltd | Real estate | 2011 |
| Willow Ward Technical Limited | Information & communication | 2011 |
| Willowbeck Health Care Limited | Health & social care | 2006 |
| Willowbeck SPV Limited | Health & social care | 2018 |
| Willowhaven Limited | Wholesale & retail | 2025 |
| Willowprop Ltd | Other services | 2026 |
| Willowround Limited | Information & communication | 2018 |
| Wills HI Line Haulage Ltd | Transport & logistics | 2025 |
| Willsbeck Properties Ltd | Real estate | 2018 |
| Willy's Wheels Ltd | Other services | 2021 |
| Wilman Property Ltd | Real estate | 2022 |
| Wilmington Trout Farm Limited | Agriculture & fishing | 2000 |
| Wilshers DEJ Ltd | Professional & scientific | 2019 |
| Wilson and Willow Ltd | Wholesale & retail | 2023 |
| Wilson Benesch Limited | Manufacturing | 1996 |
| Wilson Bros. (Sheffield) Limited | Manufacturing | 1989 |
| Wilson Brothers (Sheffield) Limited | Manufacturing | 2021 |
| Wilson Carlile Centre Limited | Hospitality | 2012 |
| Wilson Elec Ltd | Construction | 2019 |
| Wilson Electrical Mechanical Services Limited | Construction | 2016 |
| Wilson Fire Installations Limited | Construction | 2026 |
| Wilson Granite Installations Limited | Construction | 2019 |
| Wilson Howe Limited | Professional & scientific | 2016 |
| Wilson Laidler & Co Ltd | Construction | 2005 |
| Wilsonaris Ltd | Wholesale & retail | 2025 |
| Wilsonkemp CDS Ltd | Construction | 2019 |
| Wilsons & Co. (Sharrow) Limited | Wholesale & retail | 1993 |
| Wilsonsvapes Ltd | Wholesale & retail | 2021 |
| Wiltoncote Holdings NO.1 Limited | Financial services | 2009 |
| Wiltoncote Limited | Real estate | 1981 |
| Wiltshire Foot and Ankle Ltd | Health & social care | 2024 |
| Wimpton Cottages Limited | Real estate | 2020 |
| Winchester Store Ltd | Wholesale & retail | 2025 |
| Winco Deli Ltd | Hospitality | 2021 |
| Wincro Group Holdings Ltd | Professional & scientific | 2022 |
| Wincro Holdings Limited | Professional & scientific | 2008 |
| Wind Turbine Engineering Services Ltd | Professional & scientific | 2021 |
| Winder Consultancy Ltd | Other services | 2025 |
| Windermore Limited | Real estate | 1976 |
| Windmill Boarding Kennels Limited | Other services | 2014 |
| Windmill Sails Ltd | Wholesale & retail | 2023 |
| Windom Properties Ltd | Real estate | 2023 |
| Window Fitters Mate Limited | Extraterritorial | 1983 |
| Window Machinery Search Ltd | Manufacturing | 2003 |
| Window Timber Hardware Ltd | Wholesale & retail | 2009 |
| Windowcharm Limited | Construction | 2024 |
| Windowspec Limited | Construction | 2009 |
| Windsor Property Developments Ltd | Real estate | 2018 |
| Windy Fields Developments Ltd | Construction | 2026 |
| Windzor’S Bakery Limited | Manufacturing | 2023 |
| Wine Moth Ltd | Information & communication | 2026 |
| Winfive Ltd | Health & social care | 2023 |
| Wingfield Electrical Services Limited | Energy | 2006 |
| WINGFIELD4 Limited | Real estate | 2025 |
| Wingman Consultancy Ltd | Professional & scientific | 2013 |
| Wings & Slice Ltd | Hospitality | 2025 |
| Wings N Sky Travels Ltd | Administrative & support | 2023 |
| Winishiv Limited | Real estate | 2025 |
| Winn Hill 14 Limited | Professional & scientific | 2019 |