| Worthy Combe LLP | | 2023 |
| Worx Scaffolding Ltd | Construction | 2022 |
| WPA Health Trustee Limited | Professional & scientific | 2002 |
| WPA Healthcare Practice PLC | Financial services | 2010 |
| WPA Insurance Services Limited | Financial services | 1991 |
| WPA Pension Trustees Limited | Financial services | 2003 |
| WPA Property Services Limited | Real estate | 2017 |
| WPA Protocol PLC | Administrative & support | 1992 |
| Wrangway Holdings Limited | Financial services | 2021 |
| Wraxall Business Management Limited | Information & communication | 2014 |
| Wrencon Developments Limited | Construction | 1987 |
| Wrencon Limited | Construction | 1987 |
| Wright Morgan Holdings Limited | Financial services | 2021 |
| Wright Morgan Ltd | Construction | 2013 |
| Wright Morgan Topco Limited | Financial services | 2025 |
| Wrrex Limited | Real estate | 2021 |
| WSM Business Limited | Administrative & support | 2021 |
| Wsra Steam Rally Ltd | Education | 2023 |
| WSS Investments Ltd | Extraterritorial | 1938 |
| WT Estates Limited | Real estate | 2022 |
| WW Building Co Ltd | Construction | 2013 |
| WWJ Solutions Limited | Professional & scientific | 2026 |
| Wyatt Joinery Limited | Construction | 2003 |
| Wyse Cars Ltd | Transport & logistics | 2017 |
| Wyvern Joinery Limited | Construction | 2018 |
| X3 Location Limited | Information & communication | 2025 |
| X3L Property Limited | Real estate | 2025 |
| Xavier Investments Limited | Financial services | 2021 |
| Xplore Fabrication Ltd | Manufacturing | 2020 |
| Xplore Group Ltd | Manufacturing | 2021 |
| XS Health Ltd | Financial services | 2000 |
| XS Insurance Services Limited | Financial services | 1999 |
| XTN Trading Limited | Wholesale & retail | 2011 |
| Y Cwtch Cafe Limited | Hospitality | 2018 |
| Y Ffynhonnell Ltd | Other services | 2002 |
| Yarani Limited | Hospitality | 2019 |
| Yardland Limited | Real estate | 1999 |
| YAS Solutions Ltd | Professional & scientific | 2025 |
| Yasu Global Limited | Health & social care | 2022 |
| Yates Haulage Limited | Transport & logistics | 2017 |
| Yatton Investment Properties Limited | Construction | 2024 |
| Yatton Rental Properties Limited | Real estate | 2024 |
| YAU YAU Ltd | Wholesale & retail | 2025 |
| Yau&Yeung Limited | Hospitality | 2023 |
| Yealm Supplies Limited | Health & social care | 2000 |
| Yelefant Ltd | Administrative & support | 2019 |
| Yellowstone Homes Ltd | Construction | 2016 |
| Yeoman Gardens (Topsham) Management Company Limited | Households | 2023 |
| Yeovil and South Somerset Liberal Club Company Limited | Real estate | 1893 |
| Yeovil Driver Training Ltd | Education | 2022 |
| Yeti Bureau Ltd | Professional & scientific | 2025 |
| Yetminster Cars & Commercials Limited | Wholesale & retail | 2026 |
| YEW Tree (Group) Limited | Construction | 2004 |
| YEW Tree Fascia (Holdings) Limited | Financial services | 2022 |
| YEW Tree Fascia Company Limited | Extraterritorial | 2013 |
| YEW Tree Insulation Limited | Extraterritorial | 2013 |
| YGV Properties Limited | Construction | 2025 |
| Yofurn Ltd | Wholesale & retail | 2023 |
| Yolk Consulting Limited | Extraterritorial | 2013 |
| Yolo Property SW Ltd | Real estate | 2025 |
| York Mews Management Company Limited | Households | 2005 |
| Yorke Vines Ltd | Wholesale & retail | 2016 |
| Yorkshire Thistle Veterinary Services Limited | Professional & scientific | 2020 |
| YOU Thai Ltd | Hospitality | 2019 |
| Young Somerset | Education | 1997 |
| Your Cloud Accountant Limited | Professional & scientific | 2019 |
| Your Pantry Limited | Wholesale & retail | 2010 |
| Youth Unlimited CIC | Education | 2014 |
| YU Ocean Limited | Hospitality | 2023 |
| Yunice Place Ltd | Wholesale & retail | 2026 |
| Z&A Food Service Ltd | Wholesale & retail | 2026 |
| Zack Blackmore Property Group Limited | Households | 2026 |
| ZAK the VET Ltd | Financial services | 2023 |
| Zarina Szilagyi Limited | Health & social care | 2022 |
| ZD Flooring Ltd | Construction | 2024 |
| ZE Digital Ltd | Administrative & support | 2025 |
| ZEN State Technologies Limited | Information & communication | 2023 |
| Zena COX Consulting Limited | Professional & scientific | 2017 |
| Zero Based Ltd | Information & communication | 2020 |
| Zero F Consulting Limited | Administrative & support | 2025 |
| Zeroism Ltd | Professional & scientific | 2025 |
| Zest for Change Limited | Professional & scientific | 2006 |
| Zest Payroll Solutions Ltd | Administrative & support | 2019 |
| Zhang and Associates Ltd | Professional & scientific | 2026 |
| ZLM 2025 Ltd | Health & social care | 2025 |
| Zmsr Ltd | Health & social care | 2021 |
| Zwanenberg Beheer Limited | Professional & scientific | 2012 |
| Zylstra Medical Limited | Health & social care | 2013 |