| Build Craft Projects Ltd | Construction | 2022 |
| Build Group Berkshire Limited | Construction | 2025 |
| Build Operating Systems Ltd | Information & communication | 2026 |
| Build Quality Limited | Construction | 2017 |
| Build to Learn Ltd | Education | 2024 |
| Building Finesse Solution Limited | Construction | 2024 |
| Built by Rebels Limited | Information & communication | 2020 |
| Bulawayo Limited | Health & social care | 2009 |
| Bulb Bidco Limited | Financial services | 2021 |
| Bulb Midco 1 Limited | Financial services | 2021 |
| Bulb Midco 2 Limited | Financial services | 2021 |
| Bulb Topco Limited | Financial services | 2021 |
| Bullet Head Scenes Ltd | Construction | 2021 |
| Bumblebee Marketing Limited | Professional & scientific | 2018 |
| Buntang Homes Ltd | Real estate | 2025 |
| Burger Plus Staines Ltd | Hospitality | 2018 |
| Burhani Trading Limited | Construction | 2014 |
| Burritotakeaway Limited | Hospitality | 2024 |
| Burton Accountancy Ltd | Professional & scientific | 2006 |
| Business Energy Supplies UK Limited | Administrative & support | 2017 |
| Business Technology Support Limited | Wholesale & retail | 1998 |
| Butik Car Ltd | Wholesale & retail | 2019 |
| Buud Ltd | Construction | 2018 |
| Buzz Property Services Ltd | Construction | 2017 |
| BW Reed & SON Limited | Construction | 2010 |
| BW Sports Marketing Limited | Administrative & support | 2022 |
| BWC Academy Ltd | Education | 2023 |
| Bxquk Ltd | Other services | 2022 |
| Byrd House Consulting Limited | Professional & scientific | 2023 |
| C & K Management Consultancy Ltd | Energy | 2017 |
| C & W Landscapes Ltd | Administrative & support | 2010 |
| C and E Brokers Limited | Real estate | 1948 |
| C W Dental Ltd | Health & social care | 2013 |
| C&C Period Property Ltd | Real estate | 2024 |
| C&M IT Ltd | Wholesale & retail | 2026 |
| C&Ms Driving Ltd | Transport & logistics | 2017 |
| C. R. E. Haulage Limited | Transport & logistics | 2003 |
| C.D. Harris Properties Limited | Real estate | 1964 |
| C.M. Taxation Associates Ltd | Professional & scientific | 2010 |
| C.O.D.E. Trans Ltd | Transport & logistics | 2019 |
| C.P Carpentry & Construction Ltd | Construction | 2022 |
| C.R.S.Comfort Ltd | Construction | 2023 |
| C17 (UK) Ltd | Construction | 2023 |
| C2H Online Ltd | Agriculture & fishing | 2019 |
| C3E Cosmos LLP | | 2016 |
| C4 Digital Solutions Ltd | Information & communication | 2025 |
| Cabsy Bracknell Airport Express Ltd | Transport & logistics | 2025 |
| Cache & Store Ltd | Other services | 2021 |
| Cadence Design Systems Limited | Professional & scientific | 1990 |
| Cafe Bistro Ltd | Hospitality | 2023 |
| CAH Consultancy Limited | Professional & scientific | 2025 |
| Calaghan Socials Ltd | Professional & scientific | 2025 |
| Caliburn Estates Ltd | Extraterritorial | 2025 |
| California Chalet & Touring Park Ltd | Arts & recreation | 2014 |
| Calypso IT Limited | Information & communication | 2001 |
| Camelot Construction and Development Ltd | Construction | 2024 |
| Campbell Services Limited | Administrative & support | 2019 |
| Campbell West Assets Ltd | Construction | 2023 |
| Campbell West Electrical Ltd | Construction | 2023 |
| Campbell West Holdings Ltd | Financial services | 2023 |
| Campbell West Mechanical Ltd | Construction | 2017 |
| Camsec Security Ltd | Administrative & support | 2015 |
| Can.D AI Ltd | Information & communication | 2026 |
| Canaan Digital Waymakers Ltd | Information & communication | 2025 |
| Candela Group Ltd | Manufacturing | 2017 |
| Candor Commercial Projects Limited | Construction | 2015 |
| Canfolks Ltd | Wholesale & retail | 2022 |
| Canine Sense Ltd | Agriculture & fishing | 2024 |
| CAO Academy Ltd | Arts & recreation | 2023 |
| Cape Residential Ltd | Hospitality | 2019 |
| Capital Access Floors Limited | Administrative & support | 2014 |
| Capital Leadwork Ltd | Construction | 2026 |
| Capital Safety Global Holdings Limited | Professional & scientific | 2014 |
| Capoeira Wear Ltd | Wholesale & retail | 2021 |
| Car and Home Essentials Limited | Wholesale & retail | 2015 |
| Car Wash Mobile Ltd | Extraterritorial | 2021 |
| Car-Company Limited | Wholesale & retail | 2025 |
| Caramia Agencies Limited | Administrative & support | 1988 |
| Caravankingdom Ltd | Extraterritorial | 2025 |
| Cardiac Arrest Remedial Support Ltd | Health & social care | 2023 |
| Cardiovascular Imaging Solutions Limited | Information & communication | 2003 |
| Care in Your Home Ltd | Health & social care | 2010 |
| Care Without Compromise Limited | Health & social care | 2008 |
| Carecraft Support Limited | Health & social care | 2016 |
| CAREFLEXIBILITY@22 Ltd | Health & social care | 2022 |
| Carehub Services Ltd | Health & social care | 2025 |
| Caresupporttd Ltd | Health & social care | 2024 |
| Carlos Marquez Limited | Administrative & support | 2013 |
| Carls Couriers Ltd | Transport & logistics | 2026 |
| Carnaby IT Limited | Information & communication | 2024 |
| Carniraw Limited | Wholesale & retail | 2021 |
| Carol's Haven Limited | Hospitality | 2026 |
| Carpentry Craft Limited | Extraterritorial | 2014 |
| Carposh Motors Limited | Wholesale & retail | 2025 |
| Carrabeanie Climbing Limited | Arts & recreation | 2021 |
| Carrot Hospitality Ltd | Professional & scientific | 2022 |
| Cars Tree Ltd | Wholesale & retail | 2026 |
| Carshalton Electrical Services Limited | Other services | 2008 |
| Cartizo Ltd | Wholesale & retail | 2025 |
| Carvibe Private Limited | Wholesale & retail | 2024 |