| Celebration of Being Limited | Administrative & support | 2017 |
| Cemp Construction Ltd | Administrative & support | 2022 |
| Centaur Construction (SW) Limited | Construction | 2019 |
| Centre for Nutritional Excellence Limited | Other services | 1998 |
| Centrego Limited | Administrative & support | 2009 |
| Cerberus Developments Limited | Construction | 2024 |
| Certo Aerospace Limited | Professional & scientific | 2008 |
| Certo Aerospace Technologies Limited | Manufacturing | 2007 |
| CF Digital Ltd | Information & communication | 2022 |
| CFO Assist Ltd | Professional & scientific | 2022 |
| CG Business Solutions Ltd | Information & communication | 2019 |
| Changeability Limited | Professional & scientific | 2015 |
| Chant and Maidstone Limited | Professional & scientific | 2026 |
| Chantwood Consultancy Limited | Financial services | 2008 |
| Chantwood Investments Limited | Real estate | 2007 |
| Chapel Farm (Frome) Ltd | Extraterritorial | 2023 |
| Chapel Hill Park Residents Association Limited | Households | 2003 |
| Charles Holmes Limited | Construction | 2008 |
| Charleston Property Management Limited | Real estate | 2008 |
| Charltons Holdings Ltd | Real estate | 2021 |
| Charltons Property Ltd | Construction | 2016 |
| Chart Court Farms Limited | Hospitality | 1965 |
| Chatter & Chino Ltd | Hospitality | 2025 |
| Cheltenham Scaffolding Ltd | Construction | 2022 |
| Cherrington SV Ltd | Transport & logistics | 2010 |
| Cherry Gardens Equestrian Ltd | Agriculture & fishing | 2025 |
| Choc ET AL Limited | Wholesale & retail | 2019 |
| Chris Johnson Studio Limited | Information & communication | 2017 |
| Chris Martin & Sons Construction Limited | Construction | 2024 |
| Chris Nicholls Siting Services Limited | Transport & logistics | 2014 |
| Chris O'Brien Surveyors Ltd | Professional & scientific | 2022 |
| Chris Potter Consulting Ltd | Professional & scientific | 2015 |
| Chris Woolley Coaching & Consultancy Ltd | Arts & recreation | 2019 |
| Chubby Vegans Limited | Hospitality | 2022 |
| Cifer Data Systems Limited | Manufacturing | 1992 |
| CIL Strategy Consultants Holdings Limited | Professional & scientific | 2017 |
| Cipher.Events Ltd | Arts & recreation | 2026 |
| Circ Manufacturing Limited | Manufacturing | 2019 |
| Circle Instruments Ltd | Professional & scientific | 2020 |
| Cirque Entertainment Limited | Arts & recreation | 2013 |
| City FOX SET Art (SW) Ltd | Arts & recreation | 2023 |
| Cjbrowne Limited | Professional & scientific | 2014 |
| Clanville Reburbishments Limited | Real estate | 2019 |
| Clarior Futura Ltd | Real estate | 2020 |
| Clark Playground Installations Limited | Manufacturing | 2014 |
| Clark Playground Repairs Ltd | Construction | 2024 |
| Clarke & Clarke LLP | | 2006 |
| Claverton Cloches Limited | Manufacturing | 2021 |
| Clay's Orchard Ltd | Agriculture & fishing | 2025 |
| Clearbrook Close Management Limited | Households | 2021 |
| Clearspace Recycling Limited | Water & waste | 2024 |
| Cleartrack Performance Ltd | Professional & scientific | 2012 |
| Climate Live | Arts & recreation | 2020 |
| Climate Stewards | Professional & scientific | 2010 |
| CLS Wiltshire Ltd | Administrative & support | 2019 |
| Cluett's Limited | Professional & scientific | 2010 |
| CMP Complete Ltd | Construction | 2015 |
| Cnslt Limited | Professional & scientific | 2019 |
| Coaching Lane Ltd | Other services | 2007 |
| Coffee House Guitars Limited | Wholesale & retail | 2019 |
| Coker Point Limited | Construction | 2020 |
| Coleman Motorsport Ltd | Administrative & support | 2017 |
| Colenso Capital UK Limited | Financial services | 2019 |
| Collaboration Tools Limited | Professional & scientific | 2008 |
| Collabria Holdings Limited | Financial services | 2025 |
| Collabria Limited | Other services | 2025 |
| Collar Factory Limited | Real estate | 2009 |
| Colostrumco Ltd | Wholesale & retail | 2026 |
| Colour by Rosie Ltd | Other services | 2020 |
| Commerce Chamber District of Frome Limited | Other services | 1997 |
| Comms Control Limited | Arts & recreation | 2015 |
| Communa Ltd | Hospitality | 2024 |
| Community Drivers - Frome CIC | Transport & logistics | 2024 |
| Community Work Limited | Professional & scientific | 2004 |
| Compass Video Limited | Information & communication | 2016 |
| Confirmic Ltd | Information & communication | 2021 |
| Conflict Management & Business Solutions Ltd | Administrative & support | 2023 |
| Connor Construction (South West) Limited | Construction | 2008 |
| Conscious Project Limited | Other services | 2012 |
| Consulty Limited | Other services | 2021 |
| Contemporary Dental Training Ltd | Education | 2021 |
| Cooke Pipework Inspection Ltd | Construction | 2017 |
| Cool Performance Ltd | Wholesale & retail | 2017 |
| Coop Kitchen Ltd | Hospitality | 2018 |
| Cooper and Tanner 1908 Limited | Real estate | 1995 |
| Cooper and Tanner LLP | | 2007 |
| Copeland Housing Limited | Real estate | 2024 |
| COR Collective Ltd | Professional & scientific | 2024 |
| Cornish Building & Scaffolding Services Ltd | Construction | 2012 |
| Corporate. Human. Kind. Ltd | Other services | 2024 |
| Corsham PUB Company Limited | Administrative & support | 2017 |
| Cosmic Monkey Ltd | Manufacturing | 2020 |
| Country Comforts Limited | Hospitality | 2012 |
| Court Farm Adventures Limited | Hospitality | 2023 |
| Coverdale International Limited | Professional & scientific | 1983 |
| Coverdale OD Limited | Professional & scientific | 2016 |
| CPG Electrical Limited | Construction | 2011 |
| Craftbuild Building Services Limited | Construction | 2015 |
| Creative Makers CIC | Education | 2026 |
| Credit Corp Financial Services (UK) Limited | Financial services | 2016 |