| C E Garden Maintenance and Services Ltd | Other services | 2025 |
| C E S Pressure Washing Services Limited | Administrative & support | 2019 |
| C Ferreira Rope Access Limited | Mining & quarrying | 2017 |
| C H & N C Wyatt (Norfolk) Limited | Construction | 1963 |
| C H Eastwood Limited | Professional & scientific | 2021 |
| C House Arts Limited | Wholesale & retail | 2024 |
| C Illingworth Ltd | Health & social care | 2010 |
| C Inat Ltd | Professional & scientific | 2021 |
| C J Webster Electrical Limited | Wholesale & retail | 2012 |
| C Joyner Limited | Financial services | 2015 |
| C Leadbetter Builders Limited | Construction | 2015 |
| C Ledbury Plumbing & Heating Ltd | Construction | 2014 |
| C P (Norwich) Limited | Real estate | 2007 |
| C P Wilkinson Financial Services Ltd | Financial services | 2012 |
| C Pelizer Creative Design Ltd | Arts & recreation | 2018 |
| C R L Contractors Ltd | Construction | 2007 |
| C Ramsay Property Ltd | Real estate | 2022 |
| C Restaurants Ltd | Hospitality | 2020 |
| C S Conversions Limited | Manufacturing | 2012 |
| C Signs & Graphics Limited | Professional & scientific | 2019 |
| C W Atkins Group Limited | Real estate | 2002 |
| C W D Engineering Limited | Professional & scientific | 2003 |
| C W Johnson Limited | Professional & scientific | 2018 |
| C&B Recruitment Ltd | Administrative & support | 2021 |
| C&C Developments (East Anglia) Ltd | Real estate | 2013 |
| C&C Livestocks Ltd | Agriculture & fishing | 2025 |
| C&C Painters (EA) Limited | Construction | 2024 |
| C&C Properties (East Anglia) Ltd | Real estate | 2020 |
| C&C Property Group (Norfolk) Ltd | Real estate | 2026 |
| C&C Property Holdings Ltd | Real estate | 2019 |
| C&C Smiles Ltd | Health & social care | 2024 |
| C&F Bookkeeping & Accountancy Services Limited | Professional & scientific | 2012 |
| C&J Hope Properties Ltd | Construction | 2023 |
| C&K Property Services Ltd | Administrative & support | 2026 |
| C&L Dorner Ltd | Hospitality | 2024 |
| C&L Investment Group Ltd | Wholesale & retail | 2023 |
| C&L Storage Ltd | Real estate | 2022 |
| C&M Solution Ltd | Construction | 2016 |
| C&O Barbers Ltd | Other services | 2020 |
| C&P Care Ltd | Health & social care | 2022 |
| C&R Teamwear Ltd | Wholesale & retail | 2018 |
| C&S Partners UK Limited | Professional & scientific | 2021 |
| C-Cleaning Pro Limited | Administrative & support | 2025 |
| C-Lab Holdings Limited | Financial services | 2021 |
| C. & H. Quick-Mix Limited | Manufacturing | 1965 |
| C. Letlid Company Limited | Real estate | 1977 |
| C.A. Trott (Plant Hire) Limited | Construction | 1967 |
| C.A. Whitaker Limited | Financial services | 2005 |
| C.A.K. Limited | Wholesale & retail | 2010 |
| C.A.N. Fixings Limited | Wholesale & retail | 1988 |
| C.A.S.F Consultancy Ltd | Wholesale & retail | 2025 |
| C.A.S.K Services Limited | Professional & scientific | 2024 |
| C.Bell Property Ltd | Real estate | 2026 |
| C.D.M. Project Services Limited | Construction | 1995 |
| C.E. Bedwell & Sons Limited | | 1974 |
| C.E.J. Services Ltd | Construction | 2007 |
| C.G. Holdings East Anglia Ltd | Financial services | 2015 |
| C.G.C (Norfolk) Ltd | Wholesale & retail | 2010 |
| C.H.S. (Amusements) Limited | Arts & recreation | 1978 |
| C.J. Excel Medical Limited | Health & social care | 2015 |
| C.J.C. LEE (Saxthorpe) Limited | Agriculture & fishing | 1954 |
| C.K.8 Ltd. | Administrative & support | 2002 |
| C.Mtariswa Medical Ltd | Health & social care | 2014 |
| C.N. Flack & Co. Limited | Agriculture & fishing | 1950 |
| C.N.Beck & Sons Limited | Agriculture & fishing | 1961 |
| C.R. Holdings Limited | Professional & scientific | 1999 |
| C.T. Heating (Hingham) Limited | Wholesale & retail | 1979 |
| C.V. Rumsby Limited | Construction | 2003 |
| C.W. Paving Ltd | Construction | 2011 |
| C.W.Author Limited | Information & communication | 2025 |
| C.Wright & SON Gedney Limited | Agriculture & fishing | 1950 |
| C1 Trading Ltd | Wholesale & retail | 2012 |
| C4 Multimedia Ltd | Information & communication | 2005 |
| C41 Corporate Branding Limited | Manufacturing | 2009 |
| Caadio Limited | Manufacturing | 2008 |
| Caap Investments Ltd | Professional & scientific | 2022 |
| Cabana (MB) Holdings Limited | Financial services | 2021 |
| Cabin on the Coast Ltd | Hospitality | 2025 |
| Cable Networking Solutions Ltd | Information & communication | 2017 |
| Cable Sight Ltd | Information & communication | 2017 |
| Cablebarn Limited | Real estate | 1986 |
| Cablerange Limited | Extraterritorial | 2010 |
| Caboodles Salon Supplies Ltd | Administrative & support | 2017 |
| Cachet Building Services Ltd | Construction | 2022 |
| Cactus Norwich Ltd | Hospitality | 2022 |
| CAD Operations Limited | Information & communication | 2011 |
| CAD Property Maintenance Limited | Administrative & support | 2017 |
| Caddow Design and Build Ltd | Construction | 2012 |
| Cade Oilfield Services Limited | Professional & scientific | 2008 |
| Cadeler Crewing Services Limited | Administrative & support | 2008 |
| Cadeler Holdings Limited | Financial services | 2012 |
| Cadeler International Limited | Financial services | 2012 |
| Cadeler Limited | Financial services | 2025 |
| Cadeler UK Limited | Construction | 2007 |
| Cader Corp Ltd | Real estate | 2024 |
| Cadtech Building Services Limited | Real estate | 2010 |
| Cadus Vaults Ltd | Transport & logistics | 2019 |
| Caernarvon Investments Ltd | Real estate | 2019 |
| Cafe 502 Ltd | Hospitality | 2021 |
| Cafe Aroma Foods & Beverages Limited | Hospitality | 2010 |