| Buzzhr Limited | Administrative & support | 2025 |
| Bwana Holdings Ltd | Financial services | 2025 |
| Byron James Limited | Administrative & support | 1998 |
| Bytewise Ltd | Information & communication | 2020 |
| C & R Trading House Holdings Limited | Professional & scientific | 2013 |
| C a Hughes Limited | Health & social care | 2012 |
| C for Creations Limited | Real estate | 2017 |
| C Lovibond BSC ACA CTA Limited | Professional & scientific | 1998 |
| C Lovibond BSC FCA CTA Limited | Professional & scientific | 2000 |
| C R M Electrical Limited | Construction | 2000 |
| Cabinate Ltd | Manufacturing | 2026 |
| Cable Wizard Limited | Construction | 2013 |
| Cadmore Media Limited | Information & communication | 2018 |
| Caegwyn Properties Limited | Real estate | 2020 |
| Cafee Aroma Ltd | Hospitality | 2020 |
| Caira Property & Facilities Solutions Ltd | Construction | 2018 |
| Caleb-Hoedl Limited | Extraterritorial | 2017 |
| Calex UK Ltd | Professional & scientific | 2006 |
| Callum Pritchard Racing Ltd | Arts & recreation | 2025 |
| Calman Maclennan Consulting Ltd | Professional & scientific | 2026 |
| CAM Transport Consultancy Ltd | Professional & scientific | 2023 |
| Cambridge Ruskin International College Limited | Education | 2007 |
| Cambridge Sleep Sciences Ltd | Professional & scientific | 2020 |
| Camchia Limited | Administrative & support | 2021 |
| Camel Machinery Limited | Wholesale & retail | 2015 |
| Camel Tyres Limited | Wholesale & retail | 2012 |
| Campbell & Coleman Ltd | Hospitality | 2018 |
| Camphill Benevolent Fund | Health & social care | 2008 |
| CAN DO Martial Arts Ltd | Education | 2018 |
| Cancer RE Ltd | Health & social care | 2024 |
| Cannon Packing and Fulfilment Limited | Manufacturing | 2008 |
| Capital Scaffolding Oxford Ltd | Construction | 2025 |
| Capital Solar Ltd | Construction | 2019 |
| Capitis Homes Ltd | Construction | 2021 |
| Carbon Colour Company Limited | Manufacturing | 1995 |
| Carbon Node Ltd | Information & communication | 2026 |
| Carboncutuk Ltd | Manufacturing | 2023 |
| Cardinal House (Oxford) Limited | Real estate | 1998 |
| Care With Heart Ltd | Health & social care | 2018 |
| Career Atoms Ltd | Extraterritorial | 2020 |
| Caretree Limited | Health & social care | 2008 |
| Carevoice Ltd | Health & social care | 2022 |
| Carfax Media Limited | Information & communication | 2012 |
| Caringplus Healthcare Services Ltd | Health & social care | 2019 |
| Carl Adcock Fencing & Landscaping Ltd | Administrative & support | 2024 |
| Carl COX Racing WFG Ltd | Arts & recreation | 2023 |
| Carnivore Friendly Ltd | Manufacturing | 2026 |
| Cartwheel Software & Quality Consultancy Ltd | Information & communication | 2012 |
| Casa (Oxford) Ltd | Construction | 2024 |
| Caseease Ltd | Administrative & support | 2025 |
| Casewell Consulting Limited | Professional & scientific | 2013 |
| Cashmere Afro Mini Market Ltd | Wholesale & retail | 2024 |
| Caspian Films Ltd | Information & communication | 2018 |
| Cass Structural Ltd | Professional & scientific | 2020 |
| Cassis Consulting and Management Services Limited | Professional & scientific | 1965 |
| Castle BM Developments Limited | Construction | 2011 |
| Castle Management Services Ltd | Real estate | 2017 |
| Catapult Dramatic Rights Limited | Professional & scientific | 2022 |
| Catbrook Ltd | Information & communication | 2013 |
| Causeway Electrical Solutions Ltd | Construction | 2011 |
| Cbhc Developments Limited | Construction | 2024 |
| Cdma & TFW LLP | | 2010 |
| Centurion Property Solutions Limited | Real estate | 2017 |
| Century House Ellesmere Ltd | Health & social care | 2015 |
| Cert Developments Ltd | Construction | 2018 |
| Chadlington Garage Limited | Extraterritorial | 2025 |
| Chais Enterprises Limited | Education | 2021 |
| Chambrai COM Ltd | Information & communication | 2014 |
| Change for Tomorrow Ltd | Professional & scientific | 2010 |
| Chapel House Investments Limited | Financial services | 2014 |
| Chapel House Publishing Oxford Limited | Wholesale & retail | 1997 |
| Chaps Motors Limited | Wholesale & retail | 2020 |
| Charisse Limited | Wholesale & retail | 1996 |
| Charles C. Crapper Engineering Tooling Services Ltd | Professional & scientific | 1997 |
| Charles Crichton Consulting Limited | Information & communication | 2019 |
| Charlie Bishop Racing Limited | Arts & recreation | 2025 |
| Charlie Deutsch Racing Ltd | Arts & recreation | 2022 |
| Chas Winder Ltd | Information & communication | 2025 |
| Chase Construction Oxford Ltd | Construction | 2015 |
| Chekz Group Ltd | Administrative & support | 2025 |
| Chengdu Image Limited | Hospitality | 2017 |
| Chesed HA Limited | Administrative & support | 2021 |
| Chetwode Advisory Services Limited | Administrative & support | 2025 |
| Chevlelu Limited | Professional & scientific | 2015 |
| Children's Planet Ltd | Wholesale & retail | 2018 |
| Chiltern Contract Services Limited | Construction | 2022 |
| Chilterns Retreat Limited | Hospitality | 2013 |
| Chilton House Residents Management Limited | Real estate | 2014 |
| Chimney Lining Company Limited | Construction | 2012 |
| China Court Abingdon Limited | Hospitality | 2024 |
| Chipping Norton Equestrian Limited | Arts & recreation | 2023 |
| Chipping Norton Garage Limited | Wholesale & retail | 2014 |
| Christmas Cribs Limited | Manufacturing | 2002 |
| Christopher J Wilmshurst Limited | Real estate | 2012 |
| Christ’S Hospital of Abingdon Trustee Limited | Professional & scientific | 2025 |
| Chrysalism Developments Ltd | Construction | 2020 |
| Chrysalys CIC | Manufacturing | 2020 |
| Chrysoprase Ltd | Education | 2025 |
| Church Barn Residents' Company Limited | Households | 1995 |
| Church Finance Supplies Holdings Limited | Financial services | 2017 |