| Compton Mcrae Limited | Wholesale & retail | 2019 |
| Comptons Lane Limited | Households | 2004 |
| Compustack Technologies Limited | Information & communication | 1999 |
| Computer Networking & Cabling Limited | Information & communication | 1993 |
| Comtkt Limited | Information & communication | 2016 |
| Con-Tempo Furniture Limited | Manufacturing | 2018 |
| Concierge Travel Limited | Administrative & support | 2015 |
| Concorba Limited | Manufacturing | 2007 |
| Concrete Building Materials Ltd | Professional & scientific | 2019 |
| Confetti & Lace Limited | Wholesale & retail | 1994 |
| Conficio Product Design Limited | Professional & scientific | 2017 |
| Conholt Park Estate Limited | Real estate | 2018 |
| Coni Consultancy and Investments Limited | Information & communication | 2023 |
| Connaught Street (Management Company) Limited | Real estate | 1981 |
| Connect Recruiting Ltd | Administrative & support | 2024 |
| Connie Sweeney Therapies Limited | Health & social care | 2024 |
| Connolly,Crowther & Hofbauer Limited Liability Partnership | | 2004 |
| Conscientia Consultants Ltd | Professional & scientific | 2012 |
| Consilium Communications Ltd | Professional & scientific | 2012 |
| Construction & Marine Services Limited | Construction | 2004 |
| Construction Engineering & Land Survey Services Limited | Professional & scientific | 1998 |
| Consultant EYE Surgeons Partnership (London) LLP | | 2004 |
| Consultant EYE Surgeons Partnership (Surrey) LLP | | 2007 |
| Consulting at Damerham Limited | Professional & scientific | 2003 |
| Contactreal Limited | Construction | 1988 |
| Container Storage Solutions Limited | Real estate | 2019 |
| Continental Care Limited | Health & social care | 2018 |
| Controlaspect Property Management Limited | Households | 1996 |
| Contxtra Ltd | Information & communication | 2025 |
| Convenus Group Limited | Administrative & support | 2022 |
| Convenus LLP | | 2004 |
| Conveya Services Limited | Information & communication | 2018 |
| Conygar Coppicecrafts Ltd | Agriculture & fishing | 2024 |
| Cool-Merch Ltd | Wholesale & retail | 2016 |
| Cooley Carpentry and Maintenance Ltd | Construction | 2025 |
| Coombe Barns Limited | Hospitality | 2024 |
| Coombe Bissett Village Shop Limited | Real estate | 2007 |
| Cooneen at Work Limited | Wholesale & retail | 1998 |
| Cooper Venus Holdings Ltd | Real estate | 2023 |
| Copano Limited | Real estate | 2014 |
| Copper Fields (Old Newton) Management Company Limited | Real estate | 2023 |
| Copperfields Residents Management Company Limited | Households | 2021 |
| Copse Close Solar Farm Limited | Energy | 2021 |
| Copseys Nursery (Havant) Management Company Limited | Households | 2013 |
| Copthorne Grange Management Company NO 1 Limited | Households | 2010 |
| Copthorne Grange Management Company NO 2 Limited | Households | 2011 |
| Copycloud Pro Services Ltd | Administrative & support | 2026 |
| Copyprint UK Limited | Manufacturing | 1970 |
| Cordage Design Limited | Professional & scientific | 2019 |
| Cordage Development Management Limited | Construction | 2018 |
| Cordage Land & Property Limited | Real estate | 2022 |
| Core Exhibitions Limited | Wholesale & retail | 2019 |
| Coredon Ltd | Professional & scientific | 2026 |
| Corefulness Ltd | Information & communication | 2018 |
| Corill Books Limited | Wholesale & retail | 2018 |
| Corill Solutions Ltd. | Professional & scientific | 2011 |
| Cornelia Care Homes Limited | Health & social care | 2006 |
| Cornelia Holdings Ltd | Real estate | 2024 |
| Corner Pocket Limited | Information & communication | 2004 |
| Cornerstone Vision Limited | Information & communication | 2005 |
| Cornny Drinks Limited | Manufacturing | 2024 |
| Cornwall Property Limited | Professional & scientific | 2006 |
| Corona Electrical Limited | Construction | 2016 |
| Corral Limited | Wholesale & retail | 2011 |
| Cortica Ltd | Construction | 2026 |
| Coruscate Research Ltd | Professional & scientific | 2015 |
| Corvus Communications Limited | Administrative & support | 2001 |
| Coskun Handyman & Construction Ltd | Construction | 2020 |
| Coss Properties Ltd | Real estate | 2024 |
| Costessey Management Company Limited | Households | 2006 |
| Cotefield (Bodicote) Management Company Limited | Households | 2016 |
| Coton House Estate (Rugby) Management Company Limited | Households | 2016 |
| Cotswold Gate (Chipping Norton) Management Company Limited | Households | 2016 |
| Cotswolds Furniture Ltd | Wholesale & retail | 2020 |
| Coultiss Contracting Limited | Construction | 2019 |
| Counterculture Films Ltd | Information & communication | 2024 |
| Country House Building Consultants Limited | Professional & scientific | 2019 |
| County Carpets (Salisbury) Limited | Wholesale & retail | 2023 |
| County Carpets (Warehousing) Limited | Transport & logistics | 2023 |
| Court (Ossett) Management Company Limited | Households | 1992 |
| Court View House Ltd | Construction | 2017 |
| Courtier Limited | Hospitality | 2009 |
| Courtlands Drive Block "J" Management Company Limited | Households | 1991 |
| Courtlands Drive Block "L" Management Company Limited | Households | 1991 |
| Courtlands Drive Block "N" Management Company Limited | Households | 1991 |
| Courtwood Auto Repairs Limited | Wholesale & retail | 2022 |
| Covah Limited | Information & communication | 2016 |
| Coversure Roofing Homes Ltd | Construction | 2026 |
| Coversure Roofing Ltd | Construction | 2024 |
| Cowesfield Farm Ltd | Agriculture & fishing | 2026 |
| COX Family Group Ltd | Financial services | 2025 |
| Cox's Green Management Company Limited | Households | 2020 |
| CPC Building Ltd | Construction | 2021 |
| CPF Management Services Limited | Administrative & support | 2022 |
| CPH & SJH Ltd | Professional & scientific | 2024 |
| CPH Luxe Limited | Professional & scientific | 2016 |
| CPL Architecture Limited | Professional & scientific | 2016 |
| CPR Vehicle Services Ltd | Wholesale & retail | 2012 |
| Cpsr Holdings Limited | Financial services | 1999 |
| CQ Construction Ltd | Construction | 2018 |