| Conie & Weir Limited | Professional & scientific | 2022 |
| Connect Facilities Management Limited | Professional & scientific | 2020 |
| Connect Training Limited | Extraterritorial | 2015 |
| Connected Power Solutions Ltd | Construction | 2017 |
| Connections 2 Independence Ltd | Health & social care | 2020 |
| Conris Group Limited | Financial services | 2019 |
| Conscious Creator Consultants Ltd | Professional & scientific | 2021 |
| Conservatory Roofing Solutions Ltd | Manufacturing | 2009 |
| CONSOLID8 Logistics Limited | Transport & logistics | 2006 |
| Consort PR Limited | Professional & scientific | 2017 |
| Consortiums Development Ltd | Construction | 2018 |
| Constellation Business Solutions Ltd | Wholesale & retail | 2024 |
| Construction Improvements Limited | Construction | 2025 |
| Consultingfuture.Com Limited | Professional & scientific | 2018 |
| Contingent Services UK Limited | Construction | 2015 |
| Contour Holdings International Limited | Financial services | 2019 |
| Contour Technologies Limited | Financial services | 2019 |
| Contract House Investments Limited | Professional & scientific | 2003 |
| Contractible Ltd | Information & communication | 2026 |
| Controlled Environment Building Association (UK) Ltd | Other services | 1999 |
| Controlled Flow Ltd | Construction | 2018 |
| Convergent Live Ltd | Manufacturing | 2022 |
| Conversion Digital Ltd | Administrative & support | 2018 |
| Conviva Health Limited | Manufacturing | 2016 |
| Cook Logistics Limited | Transport & logistics | 2020 |
| Cook Well Cheltenham Limited | Hospitality | 2024 |
| Cooke Sheet Metal Ltd | Manufacturing | 2015 |
| Cooler Group Ltd | Construction | 2023 |
| Cooling Edge Limited | Administrative & support | 2009 |
| Coolzone Automotive Limited | Wholesale & retail | 2011 |
| Coombe Workshop Ltd | Wholesale & retail | 2018 |
| Cooper James Property Limited | Real estate | 2025 |
| Cooper Residential Developments Ltd | Real estate | 2017 |
| Cooper Richards Developments Ltd | Construction | 2025 |
| Coopers Edge (Gloucester) Management Company Limited | Households | 2007 |
| Coopers Intelligent Buildings Ltd | Information & communication | 2015 |
| Copeland Park (Phase 2) Management Company Limited | Households | 2010 |
| Copper Coach Company Limited | Hospitality | 2023 |
| Coral Developments Limited | Construction | 1990 |
| Coralco Ltd | Real estate | 2019 |
| Cordial AV Ltd | Information & communication | 2013 |
| Core Connections Reformer Ltd | Health & social care | 2025 |
| Core Developments Ltd | Real estate | 2024 |
| Core Facilities Group Ltd | Administrative & support | 2013 |
| Coreinnovateit Ltd | Information & communication | 2024 |
| Corinium Carpets Limited | Construction | 2008 |
| Corkwall Limited | Construction | 2025 |
| Cormen Limited | Health & social care | 2023 |
| Cornelius Lysaght Media Limited | Other services | 2008 |
| Cornell Services Ltd | Financial services | 2013 |
| Cornell Solutions Limited | Financial services | 2022 |
| Corner's Shop Ltd | Wholesale & retail | 2023 |
| Cornerstone ALT. Ltd | Real estate | 2022 |
| Cornerstone Architecture Ltd | Professional & scientific | 2013 |
| Cornerstone Group (Turn) Ltd | Financial services | 2016 |
| Cornerstone Structural Ltd | Professional & scientific | 2021 |
| Cornford Lands Services Ltd | Real estate | 2023 |
| Corotrading Ltd | Hospitality | 2024 |
| Corplex Plastics UK Ltd | Manufacturing | 2004 |
| Corporate Coach Training Limited | Professional & scientific | 2008 |
| Corporate Flight Deck Services Limited | Professional & scientific | 2013 |
| Correct Balance LLP | | 2012 |
| Correia Masonery Ltd | Construction | 2016 |
| Corrmed Limited | Professional & scientific | 2017 |
| Corse Grange Management Company Limited | Households | 2017 |
| Corse Grange Properties Limited | Real estate | 2023 |
| Corston Bespoke Interiors Ltd | Manufacturing | 2023 |
| Coru Coffee Limited | Manufacturing | 2026 |
| Coru Pilates Limited | Arts & recreation | 2025 |
| Corvel Software Ltd | Information & communication | 2020 |
| Cosmas Ltd | Information & communication | 2011 |
| Cosmique Properties Ltd | Real estate | 2016 |
| Cosmo Smart Services Limited | Information & communication | 2015 |
| Cost Services Ltd | Construction | 2025 |
| Cosy Plumbing & Heating Ltd | Construction | 2017 |
| Cosyflame Heating Solutions Limited | Construction | 2021 |
| Cote Ltd | Construction | 2025 |
| Cotswold Aero Club Limited(The) | Transport & logistics | 1933 |
| Cotswold Airport Transfers Ltd | Transport & logistics | 2023 |
| Cotswold Building Services Ltd | Professional & scientific | 2022 |
| Cotswold Burgers Limited | Hospitality | 2022 |
| Cotswold Business Supplies Limited | Wholesale & retail | 2017 |
| Cotswold Caterer Collection Ltd | Hospitality | 2022 |
| Cotswold Chase (Eastcombe) Management Company Limited | Households | 2012 |
| Cotswold Chic Flowers, by Julia Ltd | Wholesale & retail | 2024 |
| Cotswold Chic Ltd | Other services | 2013 |
| Cotswold Childcare Company Limited | Health & social care | 2025 |
| Cotswold Classic Cars Limited | Wholesale & retail | 2012 |
| Cotswold Clothing Ltd | Wholesale & retail | 2026 |
| Cotswold Communities First CIC | Education | 2013 |
| Cotswold Community Care Limited | Health & social care | 2023 |
| Cotswold Computer Medic Limited | Information & communication | 2008 |
| Cotswold Conservation Ltd | Construction | 2026 |
| Cotswold Conservatories (Cheltenham) Limited | Professional & scientific | 2000 |
| Cotswold Consultive Ltd | Professional & scientific | 2024 |
| Cotswold Contractors (Glos) Ltd | Agriculture & fishing | 2019 |
| Cotswold Cookie Company Limited | Extraterritorial | 2001 |
| Cotswold Core Services Ltd | Construction | 2026 |
| Cotswold Countryside Retreats Ltd | Real estate | 2025 |
| Cotswold Craft and Construction LLP | | 2025 |