| Willdrae Intelligence Ltd | Information & communication | 2025 |
| William Burrows Consulting Limited | Professional & scientific | 2016 |
| William Tarn & Co Limited | Wholesale & retail | 2024 |
| Willy in Wally Ltd | Wholesale & retail | 2022 |
| Wilverley 65 Limited | Extraterritorial | 2014 |
| Wimalasundera Limited | Health & social care | 2010 |
| Wimalasundera Property Limited | Real estate | 2024 |
| Wimbledon Autocare Co. Ltd | Manufacturing | 2008 |
| Wimbledon TV Ltd | Administrative & support | 2017 |
| Windsor Court (Wandsworth) Management Limited | Households | 1983 |
| Winefiner Ltd | Wholesale & retail | 2023 |
| Wings Traders Ltd | Wholesale & retail | 2024 |
| Winis Construction & Trading Ltd | Construction | 2019 |
| Winjit Technologies Private Limited | | 2004 |
| Winkler Heating Ltd | Construction | 2017 |
| Wise Carpentry Ltd | Construction | 2022 |
| Wise Support Ltd. | Health & social care | 2020 |
| Witham Road Residents (Isleworth) Limited | Households | 1982 |
| Withus & More Ltd | Professional & scientific | 2025 |
| Wizer Solutions Ltd | Construction | 2022 |
| Wkff Limited | Transport & logistics | 1987 |
| Wofu ( London) Property Ltd | Real estate | 2023 |
| WOK Express New Malden Ltd | Hospitality | 2025 |
| WOK Feast Limited | Hospitality | 2024 |
| Woknfish Limited | Hospitality | 2026 |
| Wood Production Limited | Construction | 2006 |
| Woodies (Sevan) Limited | Hospitality | 1997 |
| Woodlands Avenue Ltd | Professional & scientific | 2021 |
| Woodstone Building Services Limited | Construction | 2019 |
| Wordmark Limited | Professional & scientific | 2025 |
| Words by Andy Limited | Arts & recreation | 2015 |
| Working Parent Coaching Ltd | Health & social care | 2023 |
| World Metal Trader's Ltd | Wholesale & retail | 2025 |
| WOT Technology Ltd | Information & communication | 2026 |
| WOW Twenty One Limited | Wholesale & retail | 2024 |
| Wurdwot Entertainment Ltd. | Information & communication | 2021 |
| X L Motor Spares Limited | Wholesale & retail | 1989 |
| Xdhair London Beauty Company Limited | Wholesale & retail | 2023 |
| Xground UK Limited | Real estate | 2015 |
| Xiangxuan Limited | Households | 2022 |
| Xiaobao Ltd | Hospitality | 2026 |
| Xmateria Ltd | Information & communication | 2021 |
| Xpress Phone Repairs Ltd | Other services | 2020 |
| Xstek Limited | Information & communication | 2009 |
| Xuan Yuan Limited | Real estate | 2011 |
| Y E Spiritual & Creative Ltd | Arts & recreation | 2025 |
| Y&J Clinic Limited | Health & social care | 2025 |
| Yakibox Limited | Hospitality | 2019 |
| Yalla Salad Limited | Hospitality | 2026 |
| Yami Restaurants Ltd | Hospitality | 2022 |
| Yang Property Ltd | Real estate | 2018 |
| Yang YIN Technologies Ltd | Information & communication | 2023 |
| Yatrick Oukabay Limited | Wholesale & retail | 2023 |
| Yc&P Ltd | Wholesale & retail | 2024 |
| Yeldizlar Ltd | Professional & scientific | 2009 |
| Yellow Bridge Limited | Wholesale & retail | 2023 |
| Yeswecan Ltd | Health & social care | 2017 |
| Yetzer Ltd | Information & communication | 2018 |
| YFA Group Ltd | Professional & scientific | 2012 |
| Yinghua Consulting Services Ltd | Professional & scientific | 2019 |
| Yinglun International Ltd | Professional & scientific | 2024 |
| YJS Global UK Ltd | Administrative & support | 2020 |
| YK Cuisine Limited | Professional & scientific | 2014 |
| YK Development London Ltd | Construction | 2021 |
| YK Property Limited | Real estate | 2025 |
| YL Designbuild Ltd | Construction | 2020 |
| YN Catering Ltd | Hospitality | 2024 |
| Yodi Apps Ltd | Information & communication | 2023 |
| Yoon's Food Ltd | Other services | 2023 |
| Yoonc.Com Limited | Administrative & support | 2017 |
| Yori F&B Ltd | Hospitality | 2021 |
| Yori Partner Ltd | Hospitality | 2020 |
| Yorigo Ltd | Hospitality | 2020 |
| YOU ME Korean Restaurant Limited | Hospitality | 2003 |
| Youforiacake Ltd | Manufacturing | 2026 |
| Young LEE Holdings Ltd | Hospitality | 2023 |
| Young-In Architects Ltd | Professional & scientific | 2013 |
| YS Capital Limited | Wholesale & retail | 2020 |
| Yujian Bespoke Ltd | Administrative & support | 2024 |
| Zaandam Limited | | 1986 |
| Zagadka Ltd | Transport & logistics | 2021 |
| Zagarone Trading Limited | Hospitality | 2016 |
| ZAH Properties Limited | Real estate | 2021 |
| Zahtax Accountants Ltd | Professional & scientific | 2023 |
| Zamucci Limited | Information & communication | 2007 |
| Zana and Partners Ltd | Households | 2025 |
| Zaryon Enterprises Ltd | Construction | 2021 |
| Zaynanawal Ltd | Manufacturing | 2024 |
| Zebari Medical Ltd | Health & social care | 2021 |
| Zein Estates Limited | Construction | 2024 |
| Zelda & Link IT Ltd | Information & communication | 2013 |
| Zenvex Limited | Wholesale & retail | 2026 |
| Zerodotfifty Limited | Professional & scientific | 2020 |
| Zest Holding Construction Limited | Construction | 2026 |
| ZHK PVT Limited | Transport & logistics | 2025 |
| Zhongheng Estate Ltd | Real estate | 2025 |
| ZIC Supermarket Ltd | Wholesale & retail | 2017 |
| Zireta Limited | Real estate | 2025 |
| ZLH Global Ltd | Wholesale & retail | 2024 |
| Zudi Barbers Limited | Other services | 2024 |