| Capital Investment Educational Ltd | Other services | 2014 |
| Capital Pizza Limited | Hospitality | 2015 |
| Capital Pizza Realty Limited | Extraterritorial | 2015 |
| Capricorn Controls Holdings Limited | Manufacturing | 2023 |
| Capsaflex Limited | Manufacturing | 2007 |
| Capstone Intelligent Solutions UK Limited | Information & communication | 2012 |
| Capybara Ltd | Information & communication | 2017 |
| Car Body (Banbury) Limited | Wholesale & retail | 1987 |
| Car Parts Garage Ltd | Wholesale & retail | 2020 |
| Carb Zero Consultants Ltd | Professional & scientific | 2026 |
| Carbon Communities Limited | Professional & scientific | 2011 |
| Carbon Composite Solutions Ltd | Manufacturing | 2025 |
| Carbon Consulting Group Ltd | Professional & scientific | 2024 |
| Carbonara Limited | Manufacturing | 2022 |
| Carburettor Holding Ltd | Financial services | 2023 |
| Cards Online Limited | Information & communication | 2017 |
| Carewell Pest Control Limited | Agriculture & fishing | 2025 |
| Carey Investments and Lettings Ltd | Real estate | 2024 |
| Caring Ones Ltd | Health & social care | 2024 |
| Carlos Dean Coaching Ltd | Administrative & support | 2013 |
| Carnegie Construction Ltd | Construction | 2023 |
| Carpetland Ltd | Wholesale & retail | 2022 |
| Carr Marketing Limited | Wholesale & retail | 1991 |
| Carr Media Limited | Information & communication | 2014 |
| Carriage Company (Oxon) Limited | Transport & logistics | 2008 |
| Carta Family Ltd | Professional & scientific | 2025 |
| Carter Mccaw Ltd | Education | 2020 |
| Carterton Holdings Limited | Real estate | 2019 |
| Carterton Homes Ltd | Construction | 2019 |
| Cascade Events Limited | Arts & recreation | 2001 |
| Cashfriday Limited | Extraterritorial | 1990 |
| Cashmore Mortgages Ltd | Financial services | 2024 |
| Castellain Group Limited | Professional & scientific | 2024 |
| Castle Bravo Limited | Professional & scientific | 2012 |
| Castle Farm Chacombe Management Limited | Real estate | 2000 |
| Castle Framing (Banbury) Ltd | Wholesale & retail | 2013 |
| Castle House Agriculture Limited | Agriculture & fishing | 2009 |
| Castle Sales and Marketing Group LLP | | 2023 |
| Castlegate 624 Limited | Professional & scientific | 2010 |
| Castor Business Consulting Ltd | Professional & scientific | 2010 |
| Catherine Wright Limited | Education | 2000 |
| Cathy Hattam Music Ltd | Information & communication | 2023 |
| Catton Communication Ltd | Information & communication | 2012 |
| Catton Consulting Ltd | Information & communication | 2010 |
| Cawrey Construction Limited | Professional & scientific | 1949 |
| Cawrey Ltd | Construction | 1964 |
| CB Events Ltd | Arts & recreation | 2021 |
| CBT Networks Ltd | Health & social care | 2005 |
| CC Banbury Limited | Hospitality | 2021 |
| Ccelectrics Banbury Ltd | Construction | 2016 |
| Ccrescent Limited | Real estate | 2026 |
| CCS Trailers Ltd | Wholesale & retail | 2024 |
| CD Photography Limited | Professional & scientific | 2024 |
| CDR Transport Ltd | Transport & logistics | 2025 |
| Cedar Banbury Limited | Other services | 2019 |
| Cedar Bloxham Ltd | Administrative & support | 2018 |
| Cedar Deddington Limited | Other services | 2016 |
| Cedar Shipston Limited | Other services | 2019 |
| Cellet Marketing & Public Relations Limited | Administrative & support | 2011 |
| Cellet Travel Services Limited | Administrative & support | 1990 |
| Censeatis Limited | Information & communication | 2007 |
| Cent Percent Ltd | Wholesale & retail | 2024 |
| Centa Global Limited | Wholesale & retail | 2020 |
| Centenary Consulting Limited | Professional & scientific | 2025 |
| Centigrade Europe Limited | Professional & scientific | 2010 |
| Central Cabs Banbury Ltd | Transport & logistics | 2025 |
| Central to Business Ltd | Information & communication | 2016 |
| Centraleisure Hire Limited | Administrative & support | 2013 |
| Centraleisure Limited | Wholesale & retail | 2010 |
| Centrespur Corporate Services Limited | Financial services | 1975 |
| Centroplan UK Limited | Construction | 2011 |
| CEO24X7 Limited | Information & communication | 2012 |
| Ceres (Northampton) Limited | Energy | 2013 |
| CES (Europe) Ltd | Wholesale & retail | 2009 |
| CF Hilltop Holdings Limited | Real estate | 2025 |
| CFN London Limited | Manufacturing | 2000 |
| Cfpa-I Limited | Other services | 2018 |
| CGR Composites Ltd | Manufacturing | 2025 |
| CGS Construction Surveying Services Limited | Professional & scientific | 2019 |
| Chacombe Care Ltd | Health & social care | 2022 |
| Chacombe Chimney Services Limited | Construction | 2019 |
| Chacombe Consulting Limited | Professional & scientific | 2016 |
| Chacombe Pre-School Limited | Education | 2006 |
| Chadwick Town Planning Ltd | Professional & scientific | 2021 |
| Chameleon Change Management Limited | Professional & scientific | 2013 |
| Chameleon Management Limited | Professional & scientific | 2009 |
| Champagne Enterprise Limited | Arts & recreation | 2010 |
| Champion Healthcare Limited | Wholesale & retail | 2016 |
| Champion Idea Ltd | Wholesale & retail | 2019 |
| Champion Wellness Ltd | Health & social care | 2023 |
| Chandler Moore Ltd | Real estate | 2019 |
| Changing Faces Facial Aesthetics Limited | Health & social care | 2005 |
| Chaplins Cleaners Ltd | Administrative & support | 2020 |
| Chaplins Commercial Property Maintenance Ltd | Administrative & support | 2023 |
| Charingworth Grange Developments Limited | Construction | 2003 |
| Charles Court Estate Limited | Households | 2020 |
| Charles Joseph Homes Ltd | Construction | 2007 |
| Chart Associates Limited | Construction | 1998 |
| Chase Enterprise Group Limited | Financial services | 2021 |
| Chase Hospitality Limited | Hospitality | 2021 |