| Canwell Coal and Solid Fuel Supplies Limited | Wholesale & retail | 2026 |
| Canwell Consulting Group Limited | Administrative & support | 2017 |
| Canwell Interiors (Cotswolds) Limited | Wholesale & retail | 2022 |
| Capaldi Nicholls Limited | Administrative & support | 2023 |
| Capexsales Limited | Extraterritorial | 2010 |
| Capford Limited | Wholesale & retail | 2018 |
| Capital & Equity PLC | Professional & scientific | 2009 |
| Capital Assets (NE) Ltd | Extraterritorial | 2023 |
| Capital Estate Planning Limited | Professional & scientific | 2001 |
| Capital Scientific Limited | Wholesale & retail | 2021 |
| Capitalh Holdings Ltd | Financial services | 2025 |
| Capp Services Ltd | Information & communication | 2026 |
| Capri Healthcare Ltd | Information & communication | 2019 |
| Capricorn Advisory Services Limited | Professional & scientific | 2020 |
| Capsa Holdings Ltd | Financial services | 2020 |
| Capture Master Ltd | Professional & scientific | 2025 |
| Capturn Limited | Administrative & support | 2016 |
| Caqligroup Limited | Wholesale & retail | 2025 |
| Car Care Autos Limited | Manufacturing | 2004 |
| Car Dent Repair UK Limited | Wholesale & retail | 2022 |
| Car Report Ltd | Professional & scientific | 2022 |
| Car-Mel Capital Limited | Real estate | 2021 |
| Carbrook Limited | Financial services | 2025 |
| Cardbridge Ltd | Other services | 2026 |
| Cardiff Commercial Ltd | Wholesale & retail | 2023 |
| Cardio Ltd | Health & social care | 2024 |
| Cardiodoc Limited | Health & social care | 2023 |
| Cardmin Ltd | Real estate | 2005 |
| Cards and Candy Castle Bromwich Ltd | Wholesale & retail | 2014 |
| Cardwell Marketing Limited | Extraterritorial | 2003 |
| Care & Alliance Ltd | Health & social care | 2022 |
| Care Dont Stop Ltd | Professional & scientific | 2023 |
| Care Families Ltd | Administrative & support | 2019 |
| Care Family Ltd | Administrative & support | 2018 |
| Care Home Podiatry Ltd | Health & social care | 2021 |
| Care Locum Limited | Health & social care | 2017 |
| Care Move Limited | Transport & logistics | 1998 |
| Care Services (UK) Ltd | Health & social care | 2004 |
| Careerville Consulting Limited | Professional & scientific | 2025 |
| Careway Support Services Limited | Health & social care | 2024 |
| Carey Sales and Marketing Limited | Professional & scientific | 2025 |
| Caring Holding Ltd | Financial services | 2022 |
| Caring Kindergartens Limited | Health & social care | 1997 |
| Caring With Compassion Ltd | Extraterritorial | 2024 |
| Caringlove Ltd | Health & social care | 2022 |
| Carl Burnett Design Ltd. | Arts & recreation | 2011 |
| Carleton Forehoe Ltd | Wholesale & retail | 2022 |
| Carlton House Investments (Four Oaks) Limited | Real estate | 1980 |
| Carlton House Investments Limited | Real estate | 1978 |
| Carolblackburn Ltd | Administrative & support | 2023 |
| Caroline LEE Associates Limited | Professional & scientific | 2010 |
| Caron Eyre Limited | Health & social care | 2022 |
| Carousel Photography Limited | Professional & scientific | 2013 |
| Carp Catfish Hunters Europe Ltd | Administrative & support | 2019 |
| Carp Fishing Destinations Ltd | Administrative & support | 2022 |
| Carpenters Canvas Ltd | Construction | 2025 |
| Carplay-Plug UK Services Ltd | Wholesale & retail | 2025 |
| Carr Design Limited | Information & communication | 2005 |
| Carrion Electrical Ltd | Construction | 2024 |
| Carroll Business Consulting Ltd | Professional & scientific | 2005 |
| Carroway Cottage Limited | Wholesale & retail | 2018 |
| Carrwood Funeral Supplies Limited | Extraterritorial | 1994 |
| Carry My Luggage-Com Limited | Transport & logistics | 2004 |
| Cart and Carriage Events Ltd | Hospitality | 2024 |
| Carter Risk Consultancy Limited | Professional & scientific | 2012 |
| Cartwright Properties Limited | Real estate | 2023 |
| Carver & SON Limited | Real estate | 2025 |
| Carver L Anderson Social Impact Ltd | Professional & scientific | 2026 |
| Casa DE Aroma Ltd | Wholesale & retail | 2026 |
| Casablanca Property Ltd | Real estate | 2017 |
| Cascwcs Ltd | Administrative & support | 2022 |
| Case Management Solutions Group Limited | Information & communication | 2019 |
| Cask and Craft Direct Ltd | Wholesale & retail | 2018 |
| Casspenn Ltd | Hospitality | 2023 |
| Cast Iron Baths.Com Limited | Wholesale & retail | 2009 |
| Cast Welfare Ltd | Administrative & support | 2023 |
| Casting Quality Services Limited | Professional & scientific | 2019 |
| Castle Bromwich Dental Services Ltd | Health & social care | 2015 |
| Castle Court Funeral & Limousine Services Limited | Extraterritorial | 1945 |
| Castle Fast Food Ltd | Hospitality | 2018 |
| Castleclark Ltd | Professional & scientific | 2001 |
| Castlegate UK Limited | Administrative & support | 1999 |
| Castlemead Pre-Let Property Limited Partnership | | 2011 |
| Catalyst Housing and Regeneration Ltd | Construction | 2019 |
| Catem Contracting Services Ltd | Information & communication | 2010 |
| Caterpoint Systems Limited | Information & communication | 2001 |
| Catertrader Limited | Wholesale & retail | 2025 |
| Cathedrals' Administration and Finance Association | Other services | 2012 |
| Cathy Brown ABC Limited | Professional & scientific | 2010 |
| Cathylau Company Ltd | Hospitality | 2022 |
| Catra | Financial services | 2016 |
| Caversham Enterprises Limited | Professional & scientific | 2008 |
| Caviar and Chips Ltd | Wholesale & retail | 2017 |
| Cawarden Demolition Co. Limited | Wholesale & retail | 1994 |
| CB & Sons Properties Ltd | Real estate | 2024 |
| CB Building Maintenance and Renovations Limited | Construction | 2024 |
| CB Fire Limited | Professional & scientific | 2018 |
| CB Sceptre Limited | Professional & scientific | 2015 |
| Cboffices Limited | Real estate | 2024 |
| CBS Associates (UK) Limited | Professional & scientific | 2006 |