| Cadonix Ltd | Information & communication | 2012 |
| Cadover Limited | Professional & scientific | 2025 |
| Caerketton Tech Limited | Information & communication | 2014 |
| Caeruleus Genomics Ltd | Professional & scientific | 2022 |
| Caigate Hybrid Microgrid Limited | Wholesale & retail | 2018 |
| Cairn Agency Limited | Professional & scientific | 2013 |
| Caladite Ltd | Professional & scientific | 2026 |
| Calamy Cleaning Services Limited | Administrative & support | 2016 |
| Calcul HPC Ltd | Information & communication | 2019 |
| Calderon International (U.K.) Limited | Real estate | 2006 |
| Calderwood Family Investment Company Ltd | Financial services | 2017 |
| Caldtech Ltd | Information & communication | 2023 |
| Calebacuity Limited | Professional & scientific | 1991 |
| Calibre Cabling Services Limited | Information & communication | 2017 |
| Calla Purple Couture Ltd | Wholesale & retail | 2024 |
| Callista Ltd | Manufacturing | 2025 |
| Calliste Business Solutions Limited | Professional & scientific | 2009 |
| Calm & Joy Trading Ltd | Wholesale & retail | 2025 |
| Calpe SOL 52 Ltd | Real estate | 2024 |
| Calvary Chapel Oxford Limited | Other services | 2004 |
| Calway Engineering Limited | Manufacturing | 2019 |
| Cambeal Limited | Manufacturing | 1998 |
| Cambria Bridge Store Ltd | Wholesale & retail | 2018 |
| Cambridge International Qualifications Ltd | Education | 2015 |
| Cambridge School of Sports Massage Limited | Education | 2014 |
| Cambridge Technology and Policy Ltd | Professional & scientific | 2006 |
| Camden Costumes Limited | Manufacturing | 2014 |
| Camden Farm Ltd | Hospitality | 2016 |
| Cameo Shades Limited | Professional & scientific | 1984 |
| Camford Consulting Limited | Professional & scientific | 2019 |
| Camp Oxford Ltd | Other services | 2023 |
| Campana Associates Limited | Administrative & support | 2023 |
| Campera Ltd | Professional & scientific | 2024 |
| Camus Capital Ltd | Financial services | 2017 |
| Camypro Limited | Information & communication | 2014 |
| Cam’S Van’S Logistics Ltd | Water & waste | 2025 |
| Canal Cat Films Limited | Professional & scientific | 2007 |
| Canalside Technology Limited | Information & communication | 2019 |
| Cane Osteopathy Limited | Health & social care | 2014 |
| Canfield Industries Limited | Professional & scientific | 1998 |
| Canine and Security Education Centre UK Ltd | Education | 2018 |
| Canivax Limited | Professional & scientific | 2024 |
| Cannasa Limited | Wholesale & retail | 2018 |
| Canning Town Apartments Limited | Real estate | 2023 |
| Canonical Consultancy Ltd | Information & communication | 2011 |
| Canopy Clinical Support Ltd | Information & communication | 2024 |
| Canopy Cuts Limited | Agriculture & fishing | 2024 |
| Canopy Immigration Ltd | Professional & scientific | 2025 |
| Canos Ltd | Manufacturing | 2026 |
| Cantata (EOT) Limited | Administrative & support | 2020 |
| Cantata Limited | Information & communication | 2002 |
| Cantay Estates Limited | Construction | 1998 |
| Cantay Group Limited | Professional & scientific | 1992 |
| Cantay Investments Limited | Real estate | 1964 |
| CAP Coder Limited | Manufacturing | 1987 |
| Capatise Growth Partnership Limited | Financial services | 2023 |
| Cape Build Ltd | Real estate | 2021 |
| Capel Machinery Sales Ltd | Wholesale & retail | 2019 |
| Caper Oxford Ltd | Wholesale & retail | 2023 |
| Capers Bistro Limited | Hospitality | 2004 |
| Capestone UK Ltd | Wholesale & retail | 2025 |
| Capital DRY Cleaner South Ltd | Other services | 2024 |
| Capital Loan Global Group Ltd | Professional & scientific | 2021 |
| Capital Recruiters Ltd | Construction | 2022 |
| Capstone Advisory Ltd | Professional & scientific | 2010 |
| Capstone Global Library Limited | Information & communication | 2008 |
| Capstropical Ltd | Wholesale & retail | 2023 |
| Caption Small Press & Indie Comics Festival CIC | Arts & recreation | 2025 |
| Captive Seven Ltd | Hospitality | 2013 |
| Captured Sparks Limited | Information & communication | 2011 |
| Capturing Hearts Castings Ltd | Health & social care | 2022 |
| Caraleso Ltd | Arts & recreation | 2026 |
| Caraway Properties Limited | Real estate | 1974 |
| Carbine Ltd | Financial services | 2021 |
| Carbohydrate Synthesis Ltd. | Manufacturing | 1997 |
| Carbon Alternatives Limited | Professional & scientific | 2014 |
| Carbon Decoded Limited | Administrative & support | 2013 |
| Carbon Events International Ltd | Transport & logistics | 2019 |
| Carbon FC (Oxford) Ltd | Financial services | 2018 |
| Carbonmind Ltd | Information & communication | 2025 |
| Carburatori Ltd | Wholesale & retail | 2021 |
| Card Medic Limited | Professional & scientific | 2020 |
| Cardea Group Limited | Real estate | 2021 |
| Cardiac Surgery GK Ltd | Health & social care | 2019 |
| Cardiox Limited | Health & social care | 2015 |
| Care Acre Limited | Health & social care | 2019 |
| Care Association Alliance South East Ltd | Other services | 2024 |
| Care at Gloucester Limited | Real estate | 2012 |
| Care HR Ltd | Administrative & support | 2012 |
| Care Time UK Ltd | Administrative & support | 2022 |
| Careflow Medicines Management Ltd | Information & communication | 1980 |
| Carey Midgley Property Limited | Real estate | 2021 |
| Cargo Marine International Insurance Consultants Limited | Financial services | 1998 |
| Carillon Road Consulting Ltd | Information & communication | 2021 |
| Carina Martin Limited | Professional & scientific | 2015 |
| Caring Hands Locum Ltd | Administrative & support | 2023 |
| Caring Physiotherapy Ltd | Health & social care | 2020 |
| Cariol Health Ltd | Health & social care | 2016 |
| Caristo Diagnostics Limited | Health & social care | 2018 |
| Carla Marie Nadin Limited | Real estate | 2024 |