| Wetherall Consultancy Ltd | Professional & scientific | 2022 |
| WF11 Ltd | Professional & scientific | 2024 |
| Whelan Brickwork Ltd | Construction | 2019 |
| White Cheetah Limited | Wholesale & retail | 2025 |
| White Dog Woodworking Ltd | Professional & scientific | 2022 |
| White Fence Properties Limited | Real estate | 2000 |
| White Rabbit Communications Ltd | Professional & scientific | 2025 |
| White Rabbit Tattoos and Fine Art Ltd | Arts & recreation | 2024 |
| White Rose Tax Consulting Limited | Professional & scientific | 2018 |
| Whitelight Online Marketing Ltd | Wholesale & retail | 2024 |
| Whizzbyte Consultancy Ltd | Information & communication | 2019 |
| Whytematter Staffing Solutions Ltd | Administrative & support | 2022 |
| Wilbro Limited | Wholesale & retail | 2016 |
| Wild Resources Limited | Agriculture & fishing | 2002 |
| Williams Construction (Anglesey) Ltd | Real estate | 2015 |
| Williams Denton CYF | Professional & scientific | 2002 |
| Wilmslow Road Manchester Limited | Construction | 2020 |
| Wilson Computers Limited | Information & communication | 2018 |
| Wilson Kreative Ltd | Professional & scientific | 2019 |
| Wilson Nesbitt (E&W) | Professional & scientific | 2022 |
| Wilson Nesbitt LLP | | 2021 |
| Wilson Nesbitt Solicitors | Professional & scientific | 2012 |
| Wilson Nesbitt Trustees | Professional & scientific | 2025 |
| Windlesham Financial Management Ltd | Financial services | 2015 |
| Windmill Court (Ballyholme) Ltd | Extraterritorial | 2021 |
| Windmill Events Ltd | Administrative & support | 2018 |
| Windmill Guitars Ltd | Wholesale & retail | 2019 |
| Windows & Conservatories (NI) Limited | Construction | 2018 |
| Windows & Doors N.I. Ltd | Construction | 2022 |
| Windscreens and Motorspares (N.I.) Limited | Wholesale & retail | 1984 |
| Winsome Glam Ltd | Wholesale & retail | 2023 |
| Wise Measures Ltd | Professional & scientific | 2012 |
| Wisedeed Limited | Real estate | 2009 |
| Witfam SPV Limited | Real estate | 2020 |
| WJ AS1 Bristol Limited | Construction | 2023 |
| WJ GQ London Limited | Construction | 2023 |
| WJ HR Wembley Limited | Construction | 2023 |
| WJ NE1 Brighton Limited | Construction | 2025 |
| WJ OR London Limited | Construction | 2026 |
| WJ TB London Limited | Households | 2025 |
| WJ TQ Pbsa Belfast Limited | Construction | 2023 |
| WJ TR Manchester Limited | Construction | 2024 |
| Wolf & Devour Ltd. | Hospitality | 2014 |
| Wolfpark Limited | Extraterritorial | 2011 |
| Women's Alpine Adventure Club C.I.C. | Education | 2023 |
| Wood Fired Shack Bangor Ltd | Hospitality | 2024 |
| Woodland Manor (Helen's Bay) Management Company Limited | Households | 2026 |
| Woodlands Hawthornden Development Limited | Extraterritorial | 1988 |
| Woodstoc Ltd | Wholesale & retail | 2000 |
| Woodvale Cricket and Athletic Association | Arts & recreation | 1925 |
| Worcesterberry Limited | Information & communication | 2014 |
| Working of Bangor Limited | Professional & scientific | 1996 |
| World of Data Limited | Wholesale & retail | 2011 |
| Worth a Call Ltd | Administrative & support | 2024 |
| Worthington Advisory Ltd | Professional & scientific | 2026 |
| WPV Student Holdings Limited | Real estate | 2024 |
| WPV Student Limited | Real estate | 2024 |
| Wraithium Limited | Extraterritorial | 2016 |
| Wright Aero Fit Ltd | Manufacturing | 2025 |
| WWA Holdings Ltd | Wholesale & retail | 2022 |
| WYD Clothing Ltd | Financial services | 2025 |
| WYD T/A Yoursport Ltd | Wholesale & retail | 2025 |
| Wyddfa Limited | Wholesale & retail | 2020 |
| Wylie Practice Ltd | Health & social care | 2018 |
| WYN Hughes Civils Limited | Construction | 2022 |
| Wyn-Jones Real Estate Ltd | Real estate | 2019 |
| X3M Amusements Limited | Arts & recreation | 2026 |
| Xolution Technology Ltd | Information & communication | 2024 |
| Xomni Limited | Administrative & support | 2020 |
| XU and LI Food Limited | Hospitality | 2018 |
| Xzopia Ltd | Information & communication | 2013 |
| Y DYN CIG Cyfyngedig | Extraterritorial | 2003 |
| Y Nŷth Magu Ltd | Health & social care | 2025 |
| YA Filthy Animal Ltd | Other services | 2021 |
| Yanjum Limited | Wholesale & retail | 2024 |
| Yardley Investment Properties Ltd | Real estate | 2025 |
| Yardley Property Development Limited | Construction | 2023 |
| Yarrum Properties Limited | Real estate | 2004 |
| Yellow Bird Media Ltd | Professional & scientific | 2020 |
| Yempact CIC | Education | 2024 |
| Ying Yang Properties Ltd | Real estate | 2025 |
| Yiver Limited | Professional & scientific | 2017 |
| Ymgynghoriaeth Saeth Consultancy Ltd | Professional & scientific | 2025 |
| Ynni Surveys Limited | Professional & scientific | 2025 |
| Yorkshire Coated Stone Limited | Manufacturing | 2024 |
| Young Designs Ltd | Arts & recreation | 2020 |
| Younge Goals Ltd | Health & social care | 2025 |
| Your Empowered Mindset Ltd | Education | 2024 |
| Your Maths Journey Ltd | Education | 2024 |
| Ysgol Glan Aethwy Cyfyngedig | Arts & recreation | 1995 |
| Ysgubor Moelyci CIC | Other services | 2023 |
| Yugen Coffee House Ltd | Hospitality | 2017 |
| Z Cloud Solutions Ltd | Information & communication | 2025 |
| ZAK Walker & Sons Property Management Ltd | Real estate | 2025 |
| Zakani Ltd | Financial services | 2015 |
| Zamzam (Bangor) Ltd | Wholesale & retail | 2015 |
| Zavigo Limited | Information & communication | 2025 |
| ZB1990 Ltd | Manufacturing | 2026 |
| Zebs Place Ltd | Hospitality | 2022 |
| ZEN Bear Ltd | Wholesale & retail | 2019 |