| C.E.L. Building Contractors Limited | Construction | 2003 |
| C.H. & E.I. Bambridge & Sons Limited | Agriculture & fishing | 2001 |
| C4TAS Limited | Professional & scientific | 2016 |
| Cadges Farm Consulting Limited | Professional & scientific | 2016 |
| Cafe K&A Ltd | Hospitality | 2026 |
| Caim Ltd | Real estate | 2019 |
| Calite Fitness Ltd | Arts & recreation | 2025 |
| Cally Sanders Property Limited | Real estate | 2024 |
| Cally Sanders Tiling Ltd | Construction | 2022 |
| Cambridge Credentials Limited | Administrative & support | 2015 |
| Cambury Events Ltd | Administrative & support | 2026 |
| Camvac International Ltd | Manufacturing | 2023 |
| Canine Cuts Ltd | Other services | 2026 |
| Canons Kebab Ltd | Hospitality | 2019 |
| Cantium Scientific Limited | Manufacturing | 2003 |
| Capable Core Talent Limited | Administrative & support | 2016 |
| Caper Investments Limited | Real estate | 2007 |
| Carbon M.E. Ltd | Real estate | 2007 |
| Carbon Plantations 2 Limited | Agriculture & fishing | 2022 |
| Carbon Plantations Limited | Agriculture & fishing | 2020 |
| Carbrooke Hall Estate Building Company Limited | Extraterritorial | 2014 |
| Cardsmaate Limited | Wholesale & retail | 2026 |
| Carl A.R. Humphrey (Sales) Limited | Wholesale & retail | 1999 |
| Cars & Vans Ltd | Wholesale & retail | 2022 |
| Casco Maintenance Ltd | Construction | 2026 |
| Cash Building Services Limited | Construction | 2012 |
| Cash Promotion Services Limited | Wholesale & retail | 2023 |
| Castle Detailing Ltd | Professional & scientific | 2012 |
| Castle ST Cafe Ltd | Hospitality | 2021 |
| Cater Cunningham Limited | Financial services | 2010 |
| CAUSE4 Limited | Professional & scientific | 2008 |
| Cbdna Ltd | Wholesale & retail | 2019 |
| CBL Plumbing Ltd | Construction | 2026 |
| Ccdtec Limited | Construction | 2025 |
| CDG Haulage Ltd | Transport & logistics | 2024 |
| CDM 2025 Ltd | Construction | 2025 |
| CDS Safety Solutions Ltd | Professional & scientific | 2016 |
| Centaurea Limited | Agriculture & fishing | 2010 |
| Center of Care Limited | Public administration | 2024 |
| Centre Stage (Holdings) Limited | Financial services | 2026 |
| Centurion Safety Products Ltd | Manufacturing | 1879 |
| CF Automation Ltd | Manufacturing | 2024 |
| CFZ (Arts) Ltd | Arts & recreation | 2024 |
| Chalk Way Maintenance Company Limited | Extraterritorial | 2010 |
| Chalkstone Services Limited | Construction | 2022 |
| Championshipclobber Ltd | Wholesale & retail | 2025 |
| Charlton and Sons Ltd | Construction | 2018 |
| Chas Holt Ecology Ltd. | Professional & scientific | 2018 |
| Chase Moving Limited | Transport & logistics | 2024 |
| Chiller Blinds (Thetford) Limited | Manufacturing | 2016 |
| Chipchop Ltd | Information & communication | 2023 |
| Chipping Hall Barns Limited | Real estate | 2007 |
| Christian Williams Limited | Construction | 2014 |
| CI Services BSE Ltd | Transport & logistics | 2024 |
| Cicek Takeaway Limited | Hospitality | 2023 |
| CIH Plumbing & Heating Ltd | Construction | 2024 |
| Cilamum Ltd | Wholesale & retail | 2024 |
| Cilvatica Ltd | Agriculture & fishing | 2024 |
| Cititech Limited | Information & communication | 2020 |
| City Property Solutions Group Ltd | Construction | 2015 |
| CJ Commercial Ltd | Real estate | 2025 |
| Cktm Ltd | Construction | 2023 |
| Class Construction Ltd | Construction | 2023 |
| Clayland Estates Limited | Construction | 1998 |
| Clayland Homes (Hingham) Limited | Construction | 2016 |
| Clayland Homes (Shipdham) Limited | Construction | 2018 |
| Clayland Homes (South Norfolk) Limited | Construction | 2017 |
| Clayland Homes (South Wootton) Limited | Construction | 2017 |
| Clayland Homes Limited | Construction | 2008 |
| Clayland Land & Planning Limited | Professional & scientific | 2023 |
| Clear BIN Cleaning Limited | Administrative & support | 2021 |
| Clear Glass Cleaning Limited | Administrative & support | 2020 |
| Clear Pathway Consultants Ltd | Construction | 2018 |
| Clear Tender Group Limited | Information & communication | 2026 |
| Clermont Direct Ltd | Wholesale & retail | 2005 |
| Clinical Psychology Centre Ltd | Extraterritorial | 2013 |
| Clockhouse Consultants (Suffolk) Ltd | Professional & scientific | 2019 |
| Clyme Business Solutions Ltd | Professional & scientific | 2024 |
| Co-Dunkall Limited | Construction | 2009 |
| Coaching Young Minds Ltd | Other services | 2023 |
| Commercial Test and Purge Ltd | Other services | 2015 |
| Complete 24/7 Maintenance Ltd | Construction | 2018 |
| Component Solutions for Industry Limited | Manufacturing | 1999 |
| Component Solutions Holdings Limited | Financial services | 2021 |
| Comtek Holdings (UK) Limited | Financial services | 2014 |
| Comtek Ltd | Manufacturing | 2001 |
| Concept Apex Design Ltd | Professional & scientific | 2025 |
| Conway Builders ( Norfolk ) Limited | Construction | 2012 |
| Cooper Heating Services Ltd | Construction | 2023 |
| Cooper's Crew Ltd | Wholesale & retail | 2025 |
| Corderwood Limited | Real estate | 1970 |
| Cornish and Sons Limited | Transport & logistics | 2002 |
| Cosmos Transport Ltd | Transport & logistics | 2025 |
| Cosmos Transporters Ltd | Transport & logistics | 2022 |
| CP Operations Limited | Agriculture & fishing | 2021 |
| CPS Management Pentney 2004 Limited | Water & waste | 2004 |
| CPV Consulting Limited | Professional & scientific | 2007 |
| Craft ICT Limited | Information & communication | 2002 |
| Cranborne House Ltd | Wholesale & retail | 1998 |
| Craneco Lifting Services Limited | Administrative & support | 2023 |