| Burwell Gift Shop Limited | Wholesale & retail | 2013 |
| Burwell Gifts Limited | Wholesale & retail | 2013 |
| Bushey Ground Holdings Limited | Professional & scientific | 2025 |
| Bushwell Cotswold Academy Ltd | Education | 2025 |
| Business Collective Networking Ltd | Administrative & support | 2026 |
| Business Community Network Ltd | Other services | 2020 |
| Business to Host Ltd | Information & communication | 2019 |
| Busy B Events Limited | Administrative & support | 2006 |
| Butler-Valetschool Limited | Education | 2002 |
| Butlers Staffing Solutions Ltd | Administrative & support | 2024 |
| Butter Ltd | Wholesale & retail | 2024 |
| Buttercross Dental Ltd | Health & social care | 2022 |
| Buttercross Holding Ltd | Administrative & support | 2017 |
| Buttercross Lane (Management Company) Limited | Real estate | 2015 |
| Buzzard Farm Ltd | Agriculture & fishing | 2024 |
| Bwtcontractors Limited | Construction | 2021 |
| BYK Properties Ltd | Real estate | 2021 |
| C J Foggett Ltd | Construction | 2015 |
| C S Stokes and Associates Limited | Professional & scientific | 2009 |
| C&S Barlow Investments Ltd | Agriculture & fishing | 2024 |
| C.A Plastering Limited | Construction | 2020 |
| C.E.F Construction Group Limited | Construction | 2021 |
| C.J. Clarke (Timber Merchants) Limited | Wholesale & retail | 1961 |
| C36 Export Packaging Ltd | Administrative & support | 2019 |
| C9 Enterprises Ltd | Administrative & support | 2025 |
| C9 Solutions Limited | Information & communication | 2018 |
| Cadian Ltd | Manufacturing | 2024 |
| CAF Building Limited | Construction | 2025 |
| Cafe Coco Limited | Extraterritorial | 2005 |
| Cafe V Ltd | Wholesale & retail | 2026 |
| Caffeica Limited | Other services | 1987 |
| Cagnard Consultancy Ltd | Professional & scientific | 2018 |
| Caldecott Chase Management Company Limited | Households | 2006 |
| Caldigit (Europe) Limited | Information & communication | 2017 |
| Caldigit UK Limited | Wholesale & retail | 2010 |
| Calibration Engineering Services Limited | Administrative & support | 2002 |
| Call Sentinel Limited | Professional & scientific | 2026 |
| Calmac Consulting Ltd | Information & communication | 2018 |
| Calobra Digital Limited | Administrative & support | 2024 |
| Cambridge Clear Beauty Limited | Health & social care | 2016 |
| Camerons Accountancy Consultants Limited | Professional & scientific | 2003 |
| Camerons Link Limited | Administrative & support | 2012 |
| Caminoro Consulting Ltd | Professional & scientific | 2025 |
| Campbell Architects Limited | Professional & scientific | 2007 |
| Campden Wine and Spirit Co Ltd | Wholesale & retail | 2021 |
| Camuri Limited | Real estate | 2019 |
| Candlish Limited | Health & social care | 2013 |
| Candour Property Limited | Real estate | 2021 |
| Cani Investments Ltd | Wholesale & retail | 2018 |
| Canntech Ltd | Other services | 2026 |
| Canopy Compute Limited | Financial services | 2026 |
| Cantilever Investments Limited | Financial services | 2017 |
| Cantilever Scaffolding Ltd | Construction | 2022 |
| Capelin Consultants Limited | Professional & scientific | 2022 |
| Capespan International Holdings Limited | Professional & scientific | 1994 |
| Capitalactiv Ltd | Professional & scientific | 2014 |
| Captains Mill Management Company Limited | Households | 2000 |
| Captivating Ltd | Manufacturing | 2017 |
| Carbon&Design Ltd | Professional & scientific | 2011 |
| Carcel Ltd | Health & social care | 2019 |
| Cardinal Cast Slates Ltd | Manufacturing | 1994 |
| Care@Home Oxfordshire Ltd | Health & social care | 2021 |
| Carl James Consulting Limited | Information & communication | 2001 |
| Carlisle Frieda Limited | Professional & scientific | 2024 |
| Carno 1 LLP | | 2017 |
| Carno 2 LLP | | 2007 |
| Carno 2 Windfarm LLP | | 2017 |
| Caroline Singh Limited | Information & communication | 2019 |
| Carpet Options Limited | Wholesale & retail | 1984 |
| Carrick Medical Ventures Limited | Real estate | 2025 |
| Carswell Country Club Limited | Arts & recreation | 2000 |
| Carswell Golf Club Limited | Extraterritorial | 1992 |
| Cartwright Construction Corporation Ltd | Construction | 2023 |
| Caryatid Heritage & Culture Limited | Arts & recreation | 2025 |
| Casa Colectiva Ltd | Administrative & support | 2025 |
| Cashell Construction Ltd | Construction | 2019 |
| Cashflow for Life Ltd | Extraterritorial | 2013 |
| Casper Leaver Limited | Other services | 2005 |
| Cassington Builders Limited | Construction | 1996 |
| Castello Style Limited | Professional & scientific | 2017 |
| Castle Park (Wallingford) Company Limited | Households | 1997 |
| Castle Stone (Oxford) Ltd | Construction | 2025 |
| Castlefairn Forest LLP | | 2015 |
| Catharine Court (Radley) Management Company Limited | Households | 2005 |
| Catherine Matthews Interiors Limited | Professional & scientific | 2012 |
| Catling and Catling Limited | Construction | 1997 |
| CAV (Oxford) Limited | Administrative & support | 2020 |
| CB Cinder Ltd | Professional & scientific | 2021 |
| CB Fabrications Oxford Limited | Professional & scientific | 2024 |
| CB Integrated Professional Services (UK) Ltd | Agriculture & fishing | 2021 |
| CBX Consultancy Limited | Professional & scientific | 2022 |
| CC Harwell Limited | Construction | 2022 |
| CC Lime Walk Limited | Construction | 2022 |
| CC Watlington Limited | Construction | 2022 |
| CDN Distribution Ltd | Wholesale & retail | 2024 |
| Ceejay Carpets Limited | Construction | 2020 |
| Celer Technologies Limited | Professional & scientific | 2012 |
| Cellfusion Animal Health Limited | Other services | 2017 |
| Central Capital CC Ltd | Real estate | 2025 |
| Central Chauffeurs CC Ltd | Transport & logistics | 2023 |