| Carey Consultancy Ltd | Professional & scientific | 2025 |
| Cargill Farms | | 2001 |
| Cargill Investments | Financial services | 1995 |
| Caria Energy Limited | Information & communication | 2026 |
| Caribqa Limited | Professional & scientific | 2010 |
| Caring Hands (Domiciliary Care) Ltd | Health & social care | 1993 |
| CARING4OTHERS Limited | Health & social care | 2016 |
| Carl Boulton Scaffolding Limited | Construction | 1992 |
| Carl Heffer Associates Limited | Professional & scientific | 2011 |
| Carl Philpott Rhinology Limited | Health & social care | 2014 |
| Carl Wright IT Consulting Ltd | Information & communication | 2020 |
| Carleton Rode Farms Limited | Agriculture & fishing | 1982 |
| Carlmo Ltd | Hospitality | 2018 |
| Carlos Method Fitness Ltd | Arts & recreation | 2023 |
| Carlson Solutions Ltd | Wholesale & retail | 2025 |
| Carlton Financial Planning Ltd | Financial services | 2002 |
| Carlton Hall Gardens Limited | Construction | 2015 |
| Carlton Hall Limited | Health & social care | 2021 |
| Carlton Park Management Company Limited | Households | 2004 |
| Carmelite House (Jarrold) Limited | Real estate | 2005 |
| Carmichaels Fish Merchants Limited | Wholesale & retail | 2002 |
| Carnaby Autism Support Limited | Administrative & support | 2015 |
| Carnaby Creative Limited | Information & communication | 2019 |
| Carnoy-Haynes Ltd | Hospitality | 2024 |
| Carol Key Developments Limited | Construction | 1988 |
| Carolans Cleaning Services Limited | Other services | 2010 |
| Caroline Amudhan Limited | Real estate | 2021 |
| Caroline House Management Limited | Households | 1982 |
| Caromax Limited | Administrative & support | 2012 |
| Carparkers (Anglia) Limited | Administrative & support | 2018 |
| Carpets in Your Home Wirral Limited | Wholesale & retail | 2018 |
| Carr Capital Limited | Real estate | 2026 |
| Carr House Farm Energy Centre Limited | Energy | 2022 |
| Carriages Cottage Ltd | Real estate | 2022 |
| Carrington Close Management Company Limited | Real estate | 2016 |
| Carrow House Creatives CIC | Arts & recreation | 2024 |
| Carrs Property Management Limited | Real estate | 2019 |
| Cars by Appointment Limited | Extraterritorial | 2008 |
| Carscene Limited | Wholesale & retail | 2002 |
| Carsigma Limited | Professional & scientific | 2021 |
| Carson Contractors (EA) Limited | Water & waste | 2024 |
| Carstodian Ltd | Transport & logistics | 2024 |
| Carter and Fisher Property Group Ltd | Real estate | 2026 |
| Carter Concrete Limited | Professional & scientific | 2014 |
| Carter Design Limited | Professional & scientific | 2003 |
| Carter Duffy Limited | Real estate | 2003 |
| Carter Energy Limited | Professional & scientific | 2012 |
| Carter Homes Assured Ltd | Real estate | 2019 |
| Carter Homes Limited | Professional & scientific | 2010 |
| Carter Interiors Limited | Professional & scientific | 2003 |
| Carters Builders (EA) Limited | Construction | 2023 |
| Carters Contractors Limited | Construction | 2000 |
| Carters Heating Services Ltd | Construction | 2018 |
| Cartford (NW) Limited | Construction | 2009 |
| Carton Properties Ltd | Real estate | 2012 |
| Caru Brands Limited | Professional & scientific | 2018 |
| Carvalho International Football Academy Limited | Education | 2019 |
| Carvauk Diagnostics Ltd | Wholesale & retail | 2025 |
| Carvels Lettings Ltd | Real estate | 2013 |
| Cary's Flowers Ltd | Wholesale & retail | 2014 |
| Carys Meadow Management Limited | Real estate | 2011 |
| CAS Ceilings and Interiors Limited | Construction | 2024 |
| Casa Bird Ltd | Real estate | 2023 |
| Cascade Engine Centre Ltd | Transport & logistics | 2024 |
| Cascade Limited | Information & communication | 2017 |
| Casebay Limited | Real estate | 2014 |
| Caskas Limited | Health & social care | 2021 |
| Caskify Limited | Other services | 2022 |
| Caspers Grill & Pizza Ltd | Hospitality | 2019 |
| Cassa Building & Design Ltd | Administrative & support | 2013 |
| Cassandra Andrews Limited | Professional & scientific | 2018 |
| Cassandra Rogers Limited | Other services | 2013 |
| Cast Holdings Limited | Financial services | 2015 |
| Casteillas Limited | Wholesale & retail | 2013 |
| Castell Investments Limited | Financial services | 2006 |
| Castell Nominees Limited | Administrative & support | 1987 |
| Castle Colour Packaging Limited | Manufacturing | 1991 |
| Castle Electrical Services Limited | Manufacturing | 2009 |
| Castle Facilities Management Ltd | Professional & scientific | 2019 |
| Castle Fitness Limited | Arts & recreation | 2014 |
| Castle Homes Lettings Limited | Real estate | 2016 |
| Castle House Management Group Ltd | Households | 2026 |
| Castle Meadow Consultancy Ltd | Extraterritorial | 2021 |
| Castle Promotions Limited | Wholesale & retail | 1998 |
| Castle Reach (King's Lynn) Management Company Limited | Households | 2025 |
| Castlemeadow Care (Suffolk) Holdings Ltd | Health & social care | 2018 |
| Castlemeadow Care Home (Halesworth) Ltd | Health & social care | 2017 |
| Castlemeadow Retirement Living (Halesworth) Ltd | Health & social care | 2017 |
| Castlemeadow Retirement Living (Woodgate) Ltd | Health & social care | 2017 |
| Castlemeadow Retirement Living Phase 2(HALESWORTH) Ltd | Health & social care | 2017 |
| Castles Heating Limited | Construction | 2026 |
| Castleton Meadows Management Company Limited | Households | 2006 |
| Cat IS Loaf Ltd | Wholesale & retail | 2025 |
| Catalyst Farming Limited | Professional & scientific | 2022 |
| Catalyst Technology Marketing Limited | Administrative & support | 2016 |
| Cater Events Ltd | Hospitality | 2023 |
| Caterbase Ltd | Information & communication | 2025 |
| Catercheck Holdings Limited | Extraterritorial | 1999 |
| Catering and Plumbing Services Ltd. | Professional & scientific | 1992 |
| Catering House Limited | Hospitality | 2017 |