| Chippenham Vehicle Services Limited | Wholesale & retail | 2003 |
| Chippenham Youth Theatre Ltd | Arts & recreation | 2024 |
| Chipside Limited | Information & communication | 2000 |
| Chiptic Ltd | Manufacturing | 2022 |
| Chisholm Consulting Ltd | Professional & scientific | 2017 |
| Chlemsam Limited | Administrative & support | 2008 |
| Chocolate Systems Ltd | Information & communication | 2015 |
| Chris Caravan Services Ltd | Manufacturing | 2023 |
| Chris Smith Physiotherapy Limited | Health & social care | 2016 |
| Chrisalis Properties Limited | Real estate | 2012 |
| Chrome Media Productions Limited | Information & communication | 2005 |
| Chrono Info Limited | Professional & scientific | 2026 |
| Church Farm (Yatton Keynell) Management Limited | Households | 2007 |
| Church Farm Estate Events Limited | Construction | 2022 |
| Church View Croft Developments Ltd | Construction | 2019 |
| CIG Tools Ltd | Manufacturing | 2025 |
| Circuit Design Consultants Limited | Professional & scientific | 1999 |
| Cirel Tech Ltd | Information & communication | 2022 |
| Cirracloud Limited | Information & communication | 2026 |
| Citadel Environmental Solutions UK Limited | Professional & scientific | 2012 |
| Citadel International Security Services Ltd | Other services | 2009 |
| City Dressing Limited | Administrative & support | 2011 |
| City Sales Academy Limited | Education | 2025 |
| Citytv Ltd | Information & communication | 2022 |
| CJH Retail Ltd | Wholesale & retail | 2022 |
| Cjim Holdings Limited | Financial services | 2025 |
| CK Landscaping and Jetwashing Ltd | Construction | 2025 |
| CKA Hand Car Wash Ltd | Administrative & support | 2019 |
| CKA Hand Car Wash Valeting Ltd | Administrative & support | 2026 |
| CL Accounting (SW) LLP | | 2012 |
| Clare Johnston Advisory Limited | Information & communication | 2025 |
| Clarence Court Ltd | Wholesale & retail | 1971 |
| Clarionet Consulting Ltd | Professional & scientific | 2024 |
| Clark Farms Limited | Agriculture & fishing | 2012 |
| Classes Abroad Limited | Education | 2009 |
| Classic Landscapes Limited | Administrative & support | 2005 |
| Classics Traders Ltd | Wholesale & retail | 2021 |
| Claxum Group Ltd | Financial services | 2026 |
| Claxum Ltd. | Information & communication | 2009 |
| Claxum Property Ltd | Real estate | 2026 |
| Clays Away Ltd | Arts & recreation | 2021 |
| Clear Perspective Expert Services Limited | Professional & scientific | 2025 |
| Clearwater Traditional Marketing Ltd | Professional & scientific | 2014 |
| Clever Health Limited | Administrative & support | 2016 |
| Clever Lighting Ltd | Professional & scientific | 2007 |
| Cleverton Consulting Limited | Professional & scientific | 2019 |
| Clientwave Creative Limited | Information & communication | 2019 |
| Clientwave Limited | Information & communication | 2003 |
| Cliff Road View Limited | Real estate | 2025 |
| Clifton Media Holdings Ltd | Information & communication | 2013 |
| Climb (UK) Limited | Extraterritorial | 2011 |
| Clive Anstey Motor Services Limited | Wholesale & retail | 2013 |
| Clive Greenland Photography Limited | Professional & scientific | 2007 |
| Clive Millington Building & Restoration Limited | Construction | 2014 |
| CLO CLO Fragrances Ltd | Wholesale & retail | 2024 |
| Cloak and Daguerre Ltd | Arts & recreation | 2012 |
| Clockswood Consulting Limited | Professional & scientific | 2015 |
| Clockwork Asset Holdings Ltd | Financial services | 2026 |
| Cloth of Gold & Haberdashery Ltd | Wholesale & retail | 2020 |
| Cloudplease Ltd | Information & communication | 2019 |
| Club-Ed Limited | Information & communication | 2022 |
| Clue Content Ltd | Information & communication | 2022 |
| Clutx Ltd | Wholesale & retail | 2025 |
| CMC328 Limited | Hospitality | 2018 |
| CMD Recruitment Limited | Administrative & support | 2014 |
| Coaching Illumination Ltd | Education | 2024 |
| Coaching Your Life Ltd | Other services | 2020 |
| Coachstyle Limited | Wholesale & retail | 1995 |
| Cobblestones 40/49 Management Limited | Households | 1992 |
| Cobuy International Ltd | Financial services | 2020 |
| Coby Transport Ltd | Transport & logistics | 2026 |
| Cocochemistry Limited | Manufacturing | 2017 |
| Coddls Ltd | Wholesale & retail | 2019 |
| Codiun Rail Limited | Extraterritorial | 2022 |
| Coffee Gems Ltd | Manufacturing | 2017 |
| Coffee on the Corner Ltd | Hospitality | 2023 |
| Cogensis Limited | Information & communication | 2010 |
| Cogentus Consulting Limited | Professional & scientific | 2007 |
| Cognichip Ltd | Professional & scientific | 2025 |
| Coldstream Arch Ltd | Other services | 2026 |
| Cole a Y Limited | Wholesale & retail | 2018 |
| Colerne After School Club Limited | Education | 2015 |
| Colerne Preschool Limited | Education | 2019 |
| Colin Coles Limited | Professional & scientific | 2002 |
| Colin J. Romain Surveys Limited | Professional & scientific | 2014 |
| Collaborative Computing Education Ltd | Information & communication | 2026 |
| Collective Communications Ltd | Professional & scientific | 2025 |
| Collins and Collins Decorating Limited | Construction | 2020 |
| Colour Coat (South West) Limited | Other services | 2021 |
| Coma Holdings Ltd | Other services | 2017 |
| Comfort Moves Ltd | Transport & logistics | 2013 |
| Commerce Decisions Limited | Information & communication | 2001 |
| Communitatis Ltd | Administrative & support | 2009 |
| Company Watch Limited | Administrative & support | 1998 |
| Complaints Handling Investigation and Appeals Service Ltd | Professional & scientific | 2023 |
| Complete-Ed Limited | Information & communication | 2015 |
| Compton Arms Ltd | Hospitality | 2018 |
| Compton Services Limited | Administrative & support | 1999 |
| Computer Network Defence Limited | Information & communication | 2004 |
| Computism Ltd | Information & communication | 2020 |