| Woolston Place Management Company Limited | Households | 2012 |
| Wootton Bassett Barbers Limited | Other services | 2012 |
| Wootton Bassett Carnival Limited | Other services | 2007 |
| Wootton Bassett RFC Limited | Hospitality | 2015 |
| Wootton Bassett Service Station Limited | Wholesale & retail | 1981 |
| Worbey Soft Strip Demolition Services UK Ltd | Construction | 2015 |
| Worcestershire Stone Worktops Ltd | Manufacturing | 2022 |
| Work of Fiction Ltd | Professional & scientific | 2018 |
| Work Points UK Limited | Professional & scientific | 2004 |
| Workhorse Ltd | Information & communication | 2015 |
| Workline Recruitment Ltd | Administrative & support | 2025 |
| Workout Enterprises Limited | Administrative & support | 1988 |
| World Athlete Combat League Limited | Arts & recreation | 2025 |
| World of Clowns Ltd | Arts & recreation | 2021 |
| World of Craft Ltd | Wholesale & retail | 2023 |
| World Welding Alloys Limited | Wholesale & retail | 1982 |
| World Women and Youth Organisation | Health & social care | 2014 |
| Worldbelts Limited | Wholesale & retail | 2008 |
| Worldwide Biorecyclables Limited | Water & waste | 2007 |
| Worthy Carpentry Academy Ltd | Manufacturing | 2026 |
| Worthy Swimming LLP | | 2024 |
| Woulfe Investments Ltd | Real estate | 2018 |
| Wovana Homes Limited | Real estate | 2023 |
| WOW Global Game Entertainment Ltd | Wholesale & retail | 2023 |
| Wowpro Ltd | Wholesale & retail | 2025 |
| WP Gardens & Landscapes Limited | Administrative & support | 2022 |
| WP Shopfitting Limited | Construction | 2019 |
| WPK Limited | Hospitality | 2017 |
| Wrag Barn Management Ltd | Arts & recreation | 2008 |
| Wrap by Design Ltd | Wholesale & retail | 2022 |
| Wrdeup Festival C.I.C. | Arts & recreation | 2016 |
| Wrenswood Owners Company Limited | Households | 1983 |
| Wrenswood Properties Ltd | Real estate | 2025 |
| Wrgl 07697692 Limited | Extraterritorial | 2011 |
| Wright Engineering Management Ltd | Professional & scientific | 2014 |
| Wright-Cooper Consultancy Ltd | Administrative & support | 2011 |
| Write on the Money Ltd | Professional & scientific | 2022 |
| Written by Lyds Ltd | Other services | 2022 |
| Wrong Shoes Theatre Company CIC | Education | 2021 |
| Wroughton Building Contractors Limited | Construction | 2001 |
| Wroughton Investments Ltd | Real estate | 1998 |
| WST Consulting Ltd | Professional & scientific | 2025 |
| WTP117 Ltd | Real estate | 2022 |
| WUS Europe Limited | Wholesale & retail | 2009 |
| WW Occasion Cars Ltd | Administrative & support | 2015 |
| Wyck Hill Change Ltd | Information & communication | 2024 |
| Wylde Hearts Co. Ltd | Information & communication | 2025 |
| Wyse Data Tech Ltd | Information & communication | 2020 |
| Wyvern Health Limited | Health & social care | 2019 |
| X R Jiang Technical Services Limited | Information & communication | 2025 |
| X7 Services Limited | Wholesale & retail | 2016 |
| Xama Technologies Limited | Information & communication | 2018 |
| Xamitex Ltd | Health & social care | 2023 |
| Xavalanche Music Limited | Information & communication | 2021 |
| Xavico Autoworks Limited | Wholesale & retail | 2026 |
| Xavico Motors Limited | Wholesale & retail | 2025 |
| Xcellytics Ltd | Professional & scientific | 2026 |
| Xcidr Ltd | Information & communication | 2025 |
| Xelapex Care Services Ltd | Health & social care | 2026 |
| Xelapex Cleaning Services Ltd | Transport & logistics | 2025 |
| Xevis Connect Ltd | Wholesale & retail | 2022 |
| Xintec Limited | Information & communication | 2026 |
| Xintra Group Limited | Information & communication | 2025 |
| Xirtec Limited | Manufacturing | 2016 |
| Xoxo Beverages UK Ltd | Manufacturing | 2021 |
| Xpat Limited | Financial services | 2002 |
| Xperience Delivered Ltd | Other services | 2022 |
| XPF Ltd | Arts & recreation | 2018 |
| Xpress Training Limited | Professional & scientific | 2024 |
| XS Distribution Limited | Wholesale & retail | 2013 |
| Xyber-X Ltd | Administrative & support | 2024 |
| Y & K Services Ltd | Professional & scientific | 2022 |
| Y & L Retail Ltd | Wholesale & retail | 2021 |
| Y Felin International Limited | Information & communication | 2017 |
| Y&L Catering Co. Ltd | Hospitality | 2024 |
| Y9ERS Telcom Ltd | Information & communication | 2023 |
| YA & Co Accountants Ltd | Professional & scientific | 2016 |
| YA Precision PAY Ltd | Administrative & support | 2017 |
| Yaanafeo Limited | Health & social care | 2021 |
| YAK & Sun Ltd | Wholesale & retail | 2026 |
| YAK the Himalayan Kitchen Takeaway Ltd | Hospitality | 2024 |
| YANI14 Limited | Administrative & support | 2018 |
| Yanimak Fashion Limited | Manufacturing | 2025 |
| Yankai Ltd | Health & social care | 2025 |
| Yara Motor Group Limited | Wholesale & retail | 2025 |
| Yared Transport Limited | Transport & logistics | 2024 |
| Yarek's Joinery Ltd | Manufacturing | 2018 |
| Yasars Barber Ltd | Other services | 2026 |
| Yashica Technologies Limited | Information & communication | 2014 |
| Yatri Mortgages Ltd | Financial services | 2023 |
| Yaya Financial Services Limited | Professional & scientific | 2026 |
| YD Investment Property Holdings Ltd | Real estate | 2025 |
| YE Olde Forge Ltd | Information & communication | 2018 |
| YE Semiconductor Solutions Ltd | Professional & scientific | 2021 |
| Ye-Ar Pro Partners Ltd | Wholesale & retail | 2023 |
| Yellow Custard Limited | Wholesale & retail | 2021 |
| Yellow Heating and Plumbing Ltd | Construction | 2024 |
| Yellow Kitten Ltd | Real estate | 2023 |
| Yellow Present Ltd | Wholesale & retail | 2026 |
| Yellow Tiles Ltd | Professional & scientific | 2025 |