| Caminus Limited | Other services | 2019 |
| Campus Court RTM Company Limited | Households | 2025 |
| Canada Rock Developments Ltd | Real estate | 2024 |
| Canary Consultants Ltd | Extraterritorial | 2013 |
| Canary Locums Ltd | Administrative & support | 2014 |
| Canary Tutoring Ltd | Education | 2024 |
| Canary Wharf Productions Ltd | Information & communication | 2011 |
| Canarybox Limited | Other services | 2022 |
| Canaryone Enterprises Limited | Other services | 2022 |
| Candlelight Freehold Limited | Professional & scientific | 2018 |
| Candure Services Ltd | Wholesale & retail | 2010 |
| Candy Delight Ltd | Wholesale & retail | 2025 |
| Candy Floss London Ltd | Hospitality | 2023 |
| Canning Real Estate Ltd | Real estate | 2023 |
| Canopus London Ltd | Construction | 2024 |
| Canopy Films Ltd | Professional & scientific | 2011 |
| Canterbury Corp Ltd | Real estate | 2024 |
| Canvas Couture Ltd | Wholesale & retail | 2024 |
| Canvey UK Properties Ltd | Real estate | 2021 |
| CAP Space Ltd | Construction | 2023 |
| Cape Sun Limited | Real estate | 2022 |
| Cape Ubuntu Consulting Limited | Professional & scientific | 2019 |
| Capel Roofing Limited | Construction | 2018 |
| Capel Waterproofing Ltd | Construction | 2011 |
| Capital & Property Finance Ltd | Other services | 2014 |
| Capital Builders Limited | Construction | 2022 |
| Capital Clarity Accountants Ltd | Professional & scientific | 2022 |
| Capital Commercial Loans Ltd | Financial services | 2026 |
| Capital Crest Services Ltd | Wholesale & retail | 2025 |
| Capital Electric & GAS Ltd | Construction | 2016 |
| Capital Event Hire Ltd | Hospitality | 2026 |
| Capital Finance and Mortgages Ltd | Professional & scientific | 2025 |
| Capital GAS Heating Ltd | Construction | 2004 |
| Capital Gate Investments UK Ltd | Real estate | 2025 |
| Capital Guard Services Ltd | Administrative & support | 2026 |
| Capital Heights Group Ltd | Real estate | 2026 |
| Capital Heights Property Services Ltd | Real estate | 2018 |
| Capital Incorporation Ltd | Wholesale & retail | 2023 |
| Capital Investments Services Limited | Financial services | 2021 |
| Capital Mastercraft Limited | Real estate | 2003 |
| Capital Security UK Limited | Administrative & support | 2024 |
| Capitrad Advisors Limited | Financial services | 2022 |
| Capri's Pizza Limited | Wholesale & retail | 2021 |
| Capricho SA Group Ltd | Hospitality | 2023 |
| Caps Clean Energy Limited | Energy | 2024 |
| Capstone Church | Other services | 2009 |
| Capstone ITS Ltd | Other services | 2019 |
| Capsule Chic Ltd | Wholesale & retail | 2022 |
| Captain Medic Limited | Health & social care | 2019 |
| Car 4 Sale Limited | Wholesale & retail | 2025 |
| Car Brothers Limited | Financial services | 2014 |
| Car Guys London Ltd | Administrative & support | 2024 |
| Car Guyz Ltd | Wholesale & retail | 2023 |
| Car Life London Ltd | Wholesale & retail | 2019 |
| Car Mall Ltd | Wholesale & retail | 2026 |
| Car Pioneers Ltd | Wholesale & retail | 2019 |
| Car Planet Limited | Wholesale & retail | 2018 |
| Car Ride Ltd | Transport & logistics | 2026 |
| Car Windscreens Ltd | Wholesale & retail | 2025 |
| Car-Tronics (Leicester) Limited | Manufacturing | 2004 |
| Cara Engineering Solutions Limited | Construction | 2013 |
| Carat Cartel Limited | Wholesale & retail | 2025 |
| CARBON4U Ltd | Wholesale & retail | 2024 |
| Carbonix Limited | Professional & scientific | 2026 |
| Carcycle Ltd | Wholesale & retail | 2018 |
| Cardiff Roofing & Guttering Limited | Construction | 2026 |
| Cardiff School of Certified Professionals Limited | Education | 2015 |
| Cardiff Transport Services Ltd | Transport & logistics | 2022 |
| Cardigan ST Ltd | Real estate | 2025 |
| Cardiology Echo Ltd | Health & social care | 2024 |
| Cardtest Limited | Other services | 1979 |
| Care & Comfort Ltd | Manufacturing | 2014 |
| Care Airo Limited | Information & communication | 2015 |
| Care and Wellbeing Support Ltd | Health & social care | 2023 |
| Care Avenues (London) Limited | Other services | 2018 |
| Care Billing Limited | Health & social care | 2022 |
| Care Champions London Limited | Extraterritorial | 2018 |
| Care Champions Skills & Training Ltd | Administrative & support | 2024 |
| Care Champions Support Ltd | Administrative & support | 2023 |
| Care Community Project Limited | Health & social care | 2018 |
| Care Gates Services Ltd | Health & social care | 2019 |
| Care Home Solution Ltd | Health & social care | 2021 |
| Care Leaders Group CIC | Administrative & support | 2024 |
| Care Supported Living Ltd | Wholesale & retail | 2025 |
| Care Watch London Limited | Health & social care | 2022 |
| Carebridge Housing Ltd | Administrative & support | 2024 |
| Career Hacks Ltd | Education | 2025 |
| Career Online Ltd | Administrative & support | 2000 |
| Careforyouservice Ltd | Health & social care | 2020 |
| Careinmyhome Herts Ltd | Other services | 2011 |
| Careinmyhome Ltd | Health & social care | 2019 |
| Carelinc Ltd | Information & communication | 2024 |
| Caremark Services Ltd | Administrative & support | 2015 |
| Carepayes Limited | Administrative & support | 2020 |
| Careplus Alliance Ltd | Administrative & support | 2024 |
| Careplus Solutions Limited | Public administration | 2025 |
| Carepro Group Ltd | Professional & scientific | 2000 |
| Carepro Ltd | Administrative & support | 1999 |
| Careshield Limited | Information & communication | 2009 |
| Caresity Ltd | Professional & scientific | 2025 |