| Whitecroft Ventures Ltd | Real estate | 2021 |
| Whitedell Farm LLP | | 2023 |
| Whitelake Recruitment Limited | Administrative & support | 2011 |
| Whitelands Contracting Limited | Water & waste | 2019 |
| WHY NOT? (Brand Consulting) Ltd | Professional & scientific | 2024 |
| Wicker Land Company Limited | Real estate | 2023 |
| Wild Horses Enterprises Limited | Real estate | 2022 |
| Wildart Design & Exhibit Limited | Extraterritorial | 2021 |
| Wildblaze Limited | Administrative & support | 2017 |
| Wildfox Media Limited | Information & communication | 2013 |
| Wildman Property Partners Ltd | Real estate | 2026 |
| Willards Gardens Limited | Administrative & support | 2020 |
| William Diffley Consulting Engineers Limited | Professional & scientific | 2013 |
| William Pritt Ltd | Wholesale & retail | 2016 |
| Willowtree Estates Limited | Construction | 1967 |
| Windermere Rest Home Limited | Health & social care | 2025 |
| Windmill Accounts Ltd | Professional & scientific | 2017 |
| Windmill Construction Services Limited | Construction | 2024 |
| Windmill Virtual Assistants Ltd | Administrative & support | 2020 |
| Wingold Consultancy Ltd | Professional & scientific | 2023 |
| Winners Enterprise Limited | Administrative & support | 2008 |
| Winton KP Properties Ltd | Real estate | 2024 |
| Winvicto Ltd | Information & communication | 2025 |
| Wired Stunts Limited | Arts & recreation | 2017 |
| Wisdom Touch Ltd | Other services | 2019 |
| Wiseair Ltd. | Construction | 2017 |
| Withers Family Limited | Financial services | 2022 |
| Withers Holdings Limited | Financial services | 2026 |
| Wits Limited | Information & communication | 2008 |
| Witts Labour Hire Ltd | Transport & logistics | 2021 |
| Witts Supplies Limited | Professional & scientific | 2020 |
| Wizard Electrical Services Limited | Construction | 2017 |
| Wm.Nankivell & Sons Limited | Manufacturing | 1993 |
| WMP Civils Limited | Construction | 2023 |
| Wokcookin Limited | Hospitality | 2024 |
| Wolfbridge Partners Ltd | Professional & scientific | 2025 |
| Wolsey Property Developments Ltd | Real estate | 2023 |
| Woodcock Hill Management Company Limited | Water & waste | 1997 |
| Wooden APE Ltd | Real estate | 2021 |
| Woodland Lane Residents Association Limited | Households | 1964 |
| Woodlands Place (Croxley Green) Management Company Limited | Households | 2011 |
| Woodoaks Bakehouse and Fermentary CIC | Manufacturing | 2026 |
| Woodward Surveyors Trustees Limited | Administrative & support | 2024 |
| Woodworx Construction Limited | Construction | 1997 |
| Work Matters (HR) Limited | Professional & scientific | 2004 |
| Workplace Fabric Limited | Manufacturing | 2011 |
| World Avenues Ltd. | Administrative & support | 1996 |
| World Holstein Friesian Federation Ltd | Agriculture & fishing | 2008 |
| Worldserv Ltd | Administrative & support | 2018 |
| WOW Monkey Ltd | Arts & recreation | 2022 |
| WPA Consulting Limited | Information & communication | 2025 |
| Wright Builders Ltd | Construction | 2010 |
| WSL Management Ltd | Households | 2023 |
| Wtmr Ltd | Real estate | 2025 |
| Wycam Properties Limited | Households | 1992 |
| Wyzecare Company Limited | Health & social care | 2025 |
| X Algorithmic Limited | Information & communication | 2024 |
| XAL Limited | Wholesale & retail | 2008 |
| Xcaliber Gaming Limited | Professional & scientific | 2011 |
| Xecofy Ltd | Information & communication | 2017 |
| XO Music Ltd | Information & communication | 2021 |
| Xtreme Dynamic Ltd | Professional & scientific | 2023 |
| Xvantage Ltd | Information & communication | 2011 |
| Y Maalo Ltd | Arts & recreation | 2013 |
| Yamarin Consulting Limited | Professional & scientific | 2013 |
| Yappyhour Ltd | Wholesale & retail | 2026 |
| YCI Ltd | Administrative & support | 2017 |
| Year & YJ Links Limited | Hospitality | 2020 |
| Yeomans Keep Management Limited | Households | 1997 |
| YEW Glade (NO.2) Limited | Real estate | 2006 |
| Yindel Limited | Information & communication | 2010 |
| Yoghim Enterprises Limited | Wholesale & retail | 1983 |
| York House School Trust Limited | Education | 1960 |
| Yorke Road School Management Company Limited | Households | 2013 |
| Yorkshire Chinar Limited | Health & social care | 2026 |
| You'Ll Never Drink Alone Limited | Wholesale & retail | 2021 |
| Your Garden Project Limited | Administrative & support | 2014 |
| Your Social Care Ltd | Health & social care | 2018 |
| Yourcoolcottage Ltd | Hospitality | 2017 |
| Youthbuild UK | Construction | 2001 |
| Z.K Topgear Ltd | Wholesale & retail | 2020 |
| ZAR Properties Limited | Real estate | 2018 |
| Zebra Adventures Ltd | Administrative & support | 2020 |
| ZEE Soft Limited | Health & social care | 2015 |
| Zencomm Ltd | Information & communication | 2021 |
| Zenhao Ltd | Information & communication | 2017 |
| Zenith Garden Ltd | Wholesale & retail | 2023 |
| Zera PR Ltd | Professional & scientific | 2026 |
| Zetta Data Consulting Services Ltd | Information & communication | 2023 |
| Zeus Product Design Limited | Professional & scientific | 2007 |
| ZHI Brunel Ltd | Administrative & support | 2016 |
| ZIL Trading Limited | Wholesale & retail | 2025 |
| Zixon Ltd | Professional & scientific | 2013 |
| ZLK Property Ltd | Real estate | 2023 |
| Zolner X Ltd | Administrative & support | 2021 |
| Zoological Medicine Ltd | Professional & scientific | 2006 |
| Zorix Properties Ltd | Real estate | 2025 |
| ZS Aesthetics Ltd | Health & social care | 2017 |
| Zyena Limited | Administrative & support | 2017 |