| Branchtide Limited | Agriculture & fishing | 2005 |
| Branchtide Properties Limited | Real estate | 2019 |
| Branchtide Retreat Ltd | Real estate | 2026 |
| Bray Lifts Ltd | Construction | 2007 |
| Braymore Estates Ltd | Construction | 2025 |
| Breckenridge Holdings Ltd | Financial services | 2026 |
| Bretton Vehicle Repairs Ltd | Wholesale & retail | 2025 |
| Brice Tech Advisory Ltd | Extraterritorial | 2023 |
| Bridge Court South RTM Company Ltd | Households | 2018 |
| Bridget Siddle VA Limited | Administrative & support | 2024 |
| Brightbeech Developments Limited | Construction | 2015 |
| Brightbeech Group Limited | Extraterritorial | 2016 |
| Brightbeech Investments LLP | | 2009 |
| Brightbeech Property Limited | Real estate | 2011 |
| Brightbeech Westbury Limited | Real estate | 2017 |
| Brighter Steps Consultancy Ltd | Professional & scientific | 2023 |
| Broadlands Wealth Limited | Financial services | 2025 |
| Bromanco Ltd | Professional & scientific | 2012 |
| Bronze Horse Partners LLP | | 2009 |
| Brook Farm Buildings Limited | Administrative & support | 2013 |
| Brooklyn Car Finance Ltd | Wholesale & retail | 2021 |
| Brookwood Property Limited | Construction | 2019 |
| Broomco (3602) Limited | Professional & scientific | 2004 |
| BRS Holdings EOT Limited | Administrative & support | 2024 |
| BRS Holdings Limited | Extraterritorial | 2000 |
| Bruce-Chwatt Ltd | Information & communication | 2015 |
| Bruce-Payne Anaesthetics Ltd | Health & social care | 2020 |
| Bryces Farms Limited | Agriculture & fishing | 1965 |
| Bryher Surgical Limited | Health & social care | 2019 |
| Brymed Limited | Health & social care | 2019 |
| Btmw Trading Ltd | Wholesale & retail | 2024 |
| Buda Investments Limited | Real estate | 2006 |
| Budds Lane Limited | Extraterritorial | 1996 |
| Bugle Design Ltd | Professional & scientific | 2024 |
| Build Pass Ltd | Professional & scientific | 2018 |
| Buildingis (Holdings) Limited | Financial services | 2020 |
| Bukata Ltd | Health & social care | 2015 |
| Burchell Medical Services Limited | Health & social care | 2021 |
| Burn & Burn Installations Ltd | Construction | 2026 |
| Burnet House RTM Company Limited | Households | 2013 |
| Burnside (Bramshaw) Limited | Professional & scientific | 2011 |
| Burton Health and Lifestyle Services Limited | Health & social care | 2024 |
| Burwood Broadcast Limited | Information & communication | 1994 |
| Business Finance Match Limited | Financial services | 2005 |
| Butlers Mortgages Limited | Financial services | 2024 |
| Butteridge Rise Management Limited | Households | 2001 |
| Byte Service Center Limited | Other services | 2009 |
| C & L Partnership Limited | Financial services | 2018 |
| C & M Communications Consultants Limited | Information & communication | 1989 |
| C & W Medical Limited | Health & social care | 2024 |
| C a House Mortgages Ltd | Financial services | 2019 |
| C Bowden Traditional Decorating Services Limited | Construction | 2014 |
| C E G Medical Limited | Health & social care | 2017 |
| C K Composites Ltd | Manufacturing | 2023 |
| C&H Concierge Services Ltd | Professional & scientific | 2021 |
| C&L Collective Ltd | Hospitality | 2025 |
| Cadbury Engineering Ltd | Manufacturing | 2014 |
| Cadence Safety Consulting Ltd | Professional & scientific | 2024 |
| Cadoux-Hudson Holdings Limited | Extraterritorial | 2025 |
| Caesar WEK Ltd | Health & social care | 2023 |
| Cafe Coffee Corner Ltd | Hospitality | 2024 |
| Cainark Consultancy Ltd | Other services | 2025 |
| Cainark Dog Training Limited | Education | 2022 |
| Cajo Anaesthetics Ltd | Health & social care | 2022 |
| Cajo Medical LLP | | 2024 |
| Calgary Developments Ltd | Construction | 2012 |
| Calpe Financial Solutions Limited | Financial services | 2005 |
| Cambridge Knee Consultants LLP | | 2026 |
| Cambridge Knee Limited | Health & social care | 2012 |
| Campbell Pools Limited | Wholesale & retail | 2010 |
| Camper Charter Limited | Administrative & support | 2025 |
| Cancer Specialists Limited | Health & social care | 2012 |
| Candi Group Holdings Limited | Financial services | 2026 |
| Capital Homes & Construction Limited | Construction | 2004 |
| Capital Homes & Developments Limited | Construction | 2001 |
| Capture 81 Ltd | Information & communication | 2024 |
| Car Accident Repair Centre (Romsey) Limited | Wholesale & retail | 2015 |
| Car Craft Engineering Limited | Wholesale & retail | 2008 |
| Carabella Trading Limited | Wholesale & retail | 2014 |
| Carbon Neutral Printing Limited | Administrative & support | 2016 |
| Carers Together | Health & social care | 2008 |
| Carettapool Ltd | Construction | 2024 |
| Carlo's Ices and Tea Rooms Limited | Hospitality | 2010 |
| Carmen Gore Ltd | Real estate | 2019 |
| Carmichael Close Residents Company Limited | Households | 2002 |
| Caroline Court Management (Southampton) Company Limited | Households | 1989 |
| Caroline Mcguiness Private Practice Ltd | Health & social care | 2021 |
| Caroline's T Shirts Limited | Wholesale & retail | 2005 |
| Carstead Motors Ltd | Wholesale & retail | 2025 |
| Carta Homes Limited | Construction | 2018 |
| CAS Medical Services Limited | Health & social care | 2022 |
| Case Engineering (Hampshire) Limited | Professional & scientific | 2012 |
| Casey & Sons Limited | Construction | 2016 |
| Cassel Medical Limited | Health & social care | 2018 |
| Casterbridge Surgical Limited | Health & social care | 2024 |
| Catfish-Pro Limited | Wholesale & retail | 2004 |
| Cattol Ltd | Extraterritorial | 2024 |
| Catton Medical Limited | Health & social care | 2026 |
| Cavendish House Residents RTM Company Ltd | Households | 2025 |
| Caxton House Investments Limited | Construction | 2014 |