| Whitt Bros. Management Limited | Extraterritorial | 2001 |
| WIG WAM Trading Co Limited | Wholesale & retail | 1994 |
| Wigmore Lane Flats NO. 1 (Luton) Limited | Real estate | 1977 |
| Wilder Capital Limited | Real estate | 2026 |
| Willam Court Ltd | Real estate | 2022 |
| Willards Limited | Manufacturing | 2001 |
| Willetts Mews Management Company Limited | Households | 2002 |
| Williams Direct Marketing Limited | Administrative & support | 2000 |
| Willow Management (Hitchin) Limited | Households | 1993 |
| Willowforge Limited | Professional & scientific | 1991 |
| Willscript Limited | Other services | 2001 |
| Wimbledon Village SW19 Limited | Real estate | 2023 |
| Winchfield Limited | Households | 1991 |
| Windscreens UK Ltd | Wholesale & retail | 2008 |
| Windsor Court (Southgate) Management Company (NO.3) Limited | Households | 1968 |
| Winning Solutions Ltd | Professional & scientific | 2001 |
| Winter Innovation Limited | Professional & scientific | 1997 |
| Wire-Cut Technologies Limited | Manufacturing | 1998 |
| Wisepart Productions Limited | Arts & recreation | 2000 |
| Wisepart Theatre Company Limited | Arts & recreation | 1999 |
| Wishstick Limited | Wholesale & retail | 1983 |
| Within Agency Limited | Professional & scientific | 2019 |
| Wonderland Day Nursery Limited | Public administration | 1995 |
| Woodbine Services Limited | Administrative & support | 2007 |
| Woodcote Close (Cheshunt) Limited | Real estate | 1990 |
| Woodhill Building Contractors Limited | Construction | 2024 |
| Woods Commercial Ltd. | Transport & logistics | 2007 |
| Woodsilk Properties Limited | Real estate | 1988 |
| Woodstore Limited | Professional & scientific | 1994 |
| Woollensbrook Group Limited | Financial services | 2018 |
| Woollensbrook Investments Limited | Financial services | 2018 |
| Woollensbrook Swaffham Bulbeck Limited | Construction | 2018 |
| Words and People Limited | Professional & scientific | 2007 |
| Workform Environments Limited | Wholesale & retail | 2007 |
| World Aviation Consultancy Services Limited | Professional & scientific | 1994 |
| World Near ME Limited | Wholesale & retail | 2025 |
| World Sindhi Congress | Other services | 1999 |
| Worldwide Economic Solutions Limited | Mining & quarrying | 2002 |
| Worldwide Security Products Limited | Real estate | 1996 |
| Worth IT Management Limited | Information & communication | 2007 |
| Wren Accounting Limited | Administrative & support | 1997 |
| Wrens Electrical Limited | Construction | 2000 |
| WSP Investments Limited | Real estate | 1955 |
| Wuito Limited | Wholesale & retail | 2026 |
| Wyart and SON Limited | Real estate | 2007 |
| Wyddial Capital Management LLP | | 2023 |
| Xclusv Customs Ltd | Professional & scientific | 2017 |
| Xerion Ltd | Information & communication | 1999 |
| XLT Consulting Ltd | Information & communication | 2007 |
| Y5 Consulting Limited | Professional & scientific | 2024 |
| Yannish Ltd | Other services | 2016 |
| YCS Beauty Ltd | Manufacturing | 2021 |
| Yedi Group Ltd | Financial services | 2024 |
| Yestore Ltd | Wholesale & retail | 2026 |
| Yews Services (UK) Ltd. | Professional & scientific | 1986 |
| Yorkshire Car Park Holdings Ltd | Transport & logistics | 2026 |
| Your Online Therapist Ltd | Health & social care | 2024 |
| Yukon Road Freehold Limited | Extraterritorial | 2005 |
| Yukseldem Ltd | Hospitality | 2024 |
| Yummy Gummys Ltd | Hospitality | 2021 |
| Z Consultancy Limited | Information & communication | 2007 |
| Zacharia International Limited | Real estate | 1987 |
| Zeal Properties & Construction Ltd | Real estate | 2023 |
| Zecari Ltd | Information & communication | 2019 |
| Zemis CIW Ltd | Information & communication | 2021 |
| Zemis Holdings Ltd | Information & communication | 2021 |
| Zenith Hire Ltd | Transport & logistics | 2025 |
| Zorba Film Services Limited | Information & communication | 1998 |